Chemical Reactions at Isolated Single-Sites Inside Metal–Organic Frameworks

Yuemin Wang; Christof Wöll

doi:10.1007/s10562-018-2432-2

Chemical Reactions at Isolated Single-Sites Inside Metal–Organic Frameworks

Wang, Yuemin; Wöll, Christof 2018-06-02 00:00:00 Keywords Metal–organic frameworks · Thin films · Single-site catalysts · Infrared spectroscopy · Defects · Active sites 1 Introduction Metal–organic frameworks (MOFs, also known as porous * Yuemin Wang coordination polymers or PCPs) are an emerging class of [email protected] porous materials of a hybrid organic/inorganic nature that * Christof Wöll combine the properties of both organic and inorganic porous [email protected] materials [1–7]. MOFs are typically stable up to tempera- Institute of Functional Interfaces, Karlsruhe Institute tures above 250 °C (in some cases, e.g., ZIF-8 [8], maximum of Technology, 76344 Eggenstein-Leopoldshafen, Germany Vol.:(0123456789) 1 3 2202 Y. Wang, C. Wöll temperatures as high as 550 °C can be tolerated). They vacancies, play a crucial role in the catalytic process [32]. exhibit a high degree of crystallinity and have large surface Recently, it has become evident that MOFs may feature a areas. The maximum degree of porosity and the size of the variety of intrinsic structural defects and the correspond- pores clearly exceed those of zeolites. In early 2017, the ing (intentional) defect engineering is a powerful strategy number of characterised MOFs was estimated to be 70,000 for advanced control of MOF chemical properties (Fig. 1) [9]. [33, 34]. The defect engineered MOFs (DEMOFs), synthe- Due to these unique chemical and physical properties sized by tailoring of linkers and/or metal ions, have shown MOF materials have opened up new perspectives in a variety modified physical and chemical properties [33– 48]. Both of different fields, ranging from gas storage and separation to local, isolated defects [modified CUS (mCUS)] and large- chemical sensing, catalysis, and drug delivery [10–21]. With scale defects (e.g. missing nodes, mesopores, Fig. 1) can be respect to applications in heterogeneous catalysis, different formed in DEMOFs and these defects can have important aspects must be considered. First, after adding additional consequences for their applications in catalysis. Further- coupling units (e.g., carboxylic acids or pyridine-units), more, MOF materials can serve as a host matrix (support) molecules active in homogeneous catalysis can be incorpo- for loading of catalytic components such as metal or metal rated into MOFs, thus providing a strategy to unite homo- oxide nanoparticles. These confined NPs inside MOFs may geneous and heterogeneous catalysis. Second, even without show unique properties which are significantly different further functionalization, many MOFs already show inter- from conventional supported catalysts. esting catalytic properties originating from the presence of In addition to MOF powders, the standard form of MOFs coordinatively unsaturated metal sites (CUS) at the nodes. obtained by the conventional solvothermal synthesis, a num- Such CUS sites are reactive for various chemical reactions. ber of methods have been developed to fabricate monolithic, A particular advantage of such sites in MOFs is that, com- crystalline, and highly oriented MOF thin films (SURMOFs) pared to oxide-supported metal nanoparticles (NPs), these [49–58]. Among them, the kinetically controlled layer-by- metal cations are highly dispersed within the framework of layer (lbl) or liquid phase epitaxy (LPE) growth process MOFs and thus serve as isolated, “single atom” catalytic has been extensively applied to produce well-defined SUR - sites. Accordingly, the interest in porous MOF materials as MOFs with a high degree of crystalline order, both vertical potential catalysts (in particular single-site catalysts [22]) and parallel to the substrate surface [59–64]. The highly- has intensified [22– 31]. ordered SURMOFs not only retain the intrinsic properties While in some MOFs CUS-sites are an intrinsic property of the corresponding MOFs, but also allow the design of of the MOF lattice itself, in other cases such undercoordi- architectures that cannot be achieved using MOF powders nated sites are absent in the ideal structure and only occur and to supplement their applicability as chemical sensors, as a result of defect formation within the framework mate- smart membranes, electronic and optoelectronic devices, rial. In the case of heterogeneous catalysis, e.g., on oxide as well as in catalytic coatings [65–68]. More importantly, surfaces, it is well known that defect sites, such as oxygen SURMOFs deposited on conducting substrates (e.g., Au) Fig. 1 Defect-engineered MOFs (DEMOFs). The modulation of the represent perfect and defect metal sites, respectively; the green high- defect structure on the micro and meso-scale by defect linker doping lighted unit indicates the parent micropores. Reproduced with per- of the framework is shown. The blue and short red sticks represent mission from Ref. [33]. Copyright 2014 American Chemical Society perfect and defective linkers, respectively; the yellow and black balls 1 3 Chemical Reactions at Isolated Single-Sites Inside Metal–Organic Frameworks 2203 can serve as model systems for a thorough study of MOF structure characterization of catalysts. However, a reliable properties by employing virtually all surface-sensitive tech- characterization of metal species in MOFs, and particularly niques developed in Surface Science because the charging those at defect sites in DEMOFs, is a challenge. Characteri- problems often hampering the analysis of bulk MOF sam- zation with electron microscopy, for example, is extremely ples are largely reduced. difficult since MOF materials contain organic ligands Overall, the extremely high structural and compositional which can be easily damaged by the high energy electrons design ability of MOF materials holds promise for their employed in TEM. Only very recently, Zhang et al. [83] have application in catalysis, including photocatalysis and electro- reported the high-quality atomic-resolution TEM images catalysis. The reactive properties of MOFs can vary signifi- of UiO-66 by developing a suite of methods to overcome cantly depending on the modification of both metal centers the experimental obstacles. Alternatively, MOFs can be and organic linkers as well as loading of metal/oxide NPs. characterized by spectroscopic techniques such as electron In this short report, we will highlight recent advances paramagnetic resonance, X-ray spectroscopy (XPS, EXAFS, in the field of MOF catalytic applications, with the main XANES) and infrared spectroscopy (FTIR). Furthermore, emphasis being on isolated, single active sites in perfect theoretical modeling of MOFs is required to properly inter- and defect-engineered MOFs, as well as for MOF thin films pret the experimental results. and SURMOFs. We will focus on structural and electronic properties as well as chemical reactivity of the selected MOF 2.1 Pristine MOFs systems based on fundamental investigations conducted primarily by our group and our collaboration partners. For The Cu-based HKUST-1 ([Cu btc ], btc = benzene-1,3,5- 3 2 other more general information about applications of MOFs tricarboxylate) is a prototypical MOF and has been used in catalysis and other fields we refer the reader to numerous in many studies [84]. This MOF contains so-called paddle- excellent review papers published recently (see e.g., [22, wheel units, where 4 carboxylate groups are bound to a 65–82]). Cu -dimer. In this interesting catalytic unit, the metal ions We will initially discuss the chemical reactions catalyzed are under-coordinated and can bind additional molecular by perfect and defect-engineered MOFs (e.g., Cu-HKUST-1, species (e.g., CO, H O, pyridine) at the axial position of the Ru-HKUST-1) using a combined experimental and theoreti- paddle-wheel units. Indeed, the CO oxidation reaction can cal approach. This section will be followed by a brief review be catalyzed by HKUST-1 at ambient pressure and elevated of the chemical nature and catalytic activity of SURMOF temperatures [85, 86]. In order to gain deeper insights into thin films. The next sections will focus on homochiral MOFs the active sites and reaction mechanisms, this system was as well as on metal and metal–oxide NPs embedded inside systematically investigated by using high-resolution ultra- MOFs. Finally, the enormous potential of SURMOF-based high vacuum infrared spectroscopy (UHV-FTIRS) in con- materials with respect to electrocatalysis will be highlighted. junction with density functional theory (DFT) calculations [87]. The sophisticated UHV-FTIRS apparatus combines a vacuum FTIR spectrometer (Bruker Vertex 80v) with a 2 Coordinatively Undercoordinated multi-chamber UHV system (Prevac), which not only ena- Single Active Sites in Pristine bles in situ transmission IR experiments on MOF powders and Defect‑Engineered MOFs (DEMOFs) supported on an inert metal mesh, but also allows the record- ing of IR reflection absorption spectroscopy (IRRAS) data To date, MOF materials have been extensively investigated, using a grazing incidence geometry on SURMOF thin films. and tremendous effort has been dedicated to their synthesis, This methodology has been demonstrated to be an invaluable properties and applications. However, a thorough atomic- tool to monitor chemical and photochemical reactions on the level understanding of structural and electronic properties surface of metal oxide powders [32]. 2+ −1 of the isolated, single active metal sites (CUS and mCUS) As shown in Fig. 2, the intrinsic Cu CUS (2179 cm ) as well as the structure–activity relationship continues to be was identified as the predominant species in HKUST-1, a major challenge; many crucial issues remain unanswered. while a small amount of native Cu defects were detected −1 This lack of information is due to the great complexity of as minor species (2125 cm , a few percent), in line with nanostructured MOFs, especially for DEMOFs in the pres- the observation for HKUST-1 thin films (see below in the ence of the different types of defects described below. A section of SURMOFs) [88]. Upon exposure to O , the UHV- comprehensive and fundamental understanding of active FTIRS data provide direct spectroscopic evidence for a sur- metal sites requires state-of-the-art analytical techniques prisingly high catalytic activity of Cu–MOFs (HKUST-1 that are suitable to probe the local chemical environments. and MOF-14, [Cu btb ], btb = 1,2,3-benzenetrisbenzoate). 3 2 Microscopic techniques [e.g., high-resolution transmis- Clearly, the presence of dioxygen leads to CO oxidation sion electron microscopy (HRTEM)] are powerful tools for even at temperatures as low as 105 K. The spectroscopic 1 3 2204 Y. Wang, C. Wöll Fig. 2 a UHV-FTIR spectra obtained after exposing [Cu btc ] cules adsorb on opposing paddle-wheel units in the iso configuration; 2 3 (HKUST-1) first to CO and subsequently to O at 105 K for differ -the O molecule is located (symmetrically) between these fragments 2 2 ent times (top). Intensity of the IR bands as a function of time for (top). Resulting structure: two C O molecules adsorb on different different CO species in the presence of molecular oxygen at 105 K paddle-wheel units (bottom). Reproduced with permission from Ref. (bottom). b Structure of HKUST-1. c Schematic representation of the [87]. Copyright 2012 John Wiley and Sons hypothetical reaction mechanism. Starting structure: two CO mole- information demonstrated that this reaction takes place only very interesting. Such modifications, of the general type 2+ on the intrinsic Cu CUS, whereas, rather unexpectedly, [M (btc) ], can be obtained by incorporating Mo [94], 3 2 the Cu defect sites are inactive for the low-temperature CO Cr [95], or Zn [96] into the parent MOF structure. These oxidation. On the basis of the high-level quantum chemical HKUST-1 analogues possess coordinatively unsaturated calculations, a concerted mechanism was proposed, whereby metal dimers at axial positions of paddle-wheel units where the impinging O molecule is activated in the presence of adsorption and chemical reactions may take place. More pre-adsorbed CO and interacts simultaneously with two iso- challenging is the synthesis of HKUST-1 analogues where carbonyl species at neighboring CUS to yield two C O mol- the central pair consists of metal ions in different charge ecules (see Fig. 2). Notably, this mechanism differs entirely states, thus yielding heterovalent paddle-wheel units. Such from those reported to occur in the case of CO oxidation mixed-valence MOFs are expected to show redox activities on metal oxides or on oxide-supported metal NPs (see e.g., [97, 98] and electric conducting properties [99, 100] that [89–93]). could be applicable to a porous electrode for batteries, fuel From a catalytic point of view, isostructural MOF vari- cells, capacitors, etc. ants of HKUST-1 where Cu is replaced by other metals are 1 3 Chemical Reactions at Isolated Single-Sites Inside Metal–Organic Frameworks 2205 In contrast to all other known [M (btc) ] frameworks that energies (see Fig. 3). These findings suggest that similar 3 2 II,II II,III are based on M units, the Ru–MOF, [Ru (btc) Cl ], complexity must be taken into explicit account for many 2 3 2 1.5 II,III exhibits mixed-valence R u paddle-wheel units with two other mixed valence MOFs with intrinsically low-coordi- 2+ 3+ differently charged metal centers (Ru and Ru ), which nated metal sites (CUS), which has not yet been accom- are stabilized by additional counter ions Cl (or in general plished in accurate detail. − − other X species such as OH ) to obtain an overall charge- neutral framework [101]. The combined results of UHV- 2.2 DEMOFs: Organic Linker Engineering FTIRS measurements using CO and CO as probe molecules and of accurate DFT calculations revealed that the structural The above discussion of MOF catalytic properties focuses and electronic properties of mixed-valence Ru–MOFs were mainly on reactant adsorption and reactive transformations much more complex than expected, and a straightforward occurring at CUS exposed at the metal ion nodes of the assignment of the observed IR bands was impossible. Two framework. However, the restricted specificity and the con- kinds of CO species bound to Ru cation sites were iden- fined coordination space of native CUS impose significant tified based on the isotopic substitution and temperature- limitations, and many MOF-types (e.g., layer-pillared MOFs 16 −1 dependent IR data (Fig. 3). The C O band at 2171 cm where Cu-paddlewheel-bound, 2D planes are stacked using, −1 18 (2120 cm for C O) was attributed to a weakly bonded e.g., bi-pyridine units) do not contain coordinatively unsatu- 16 −1 CO species, whereas the low-lying C O band at 2137 cm rated sites. In analogy to heterogeneous catalysts (e.g., metal −1 18 (2085 cm for C O) originated from a CO species with an oxides and supported metal NPs), where defects are known enhanced binding energy. A reasonable assignment, leading to be the active sites in catalysis [102], it is interesting to to the best-match between DFT calculations on both model also consider defects in MOFs. As shown in Fig. 2, reduced systems and experimental data, is based on the assumption Cu species were observed to occur as intrinsic defects (with that one of the Cl counter ions is transferred to a neighbor- a density of a few percent) in HKUST-1. ing paddle-wheel, forming an anionic secondary building Such defects should be absent in the perfect MOF lattice, unit blocked by two Cl counterions. As a consequence, the and, indeed, more sophisticated MOF fabrication methods II,III other positively charged paddle-wheel with a Ru dimer have been shown to reduce the concentrations of structural exposes two “free” CUS, where two different Ru–CO spe- imperfections [103], which can act as color centers [104]. cies could be formed with different frequencies and binding For “real” MOFs, however, the concentration of defects may Fig. 3 Temperature-dependent UHV-FTIR spectra obtained after and CO coordinated benzoate Ru-dimer paddle wheel systems as 16 18 exposing the clean Ru–MOF to a C O and b C O at 90 K and then models for local structures of Ru–MOF (atom coloring: ruthenium, 16 18 elevating the temperatures. a, b, (A) exposure to CO/ C O at 90 K; green; chlorine, magenta; carbon, black; oxygen, red; hydrogen, and heated to (B) 100 K, (C) 110 K, (D) 120 K, (E) 130 K, (F) 140 K, white). Reproduced with permission from Ref. [101]. Copyright 2013 (G) 150 K, (H) 160 K, (I) 170 K, (J) 180 K, and (K) 190 K. c Com- American Chemical Society puted model systems of CO adsorption for different scenarios of Cl 1 3 2206 Y. Wang, C. Wöll be sizeable, yielding different types of unsaturated sites numbers. Consequently, more CO molecules can adsorb to which strongly affect the chemical and physical properties of Cu mCUS with a higher binding energy with respect to 2+ 2+ these porous materials [105–112]. In this context, the inten- the parent Cu /Cu nodes, as confirmed by temperature- tional and controlled introduction of various defects into dependent IR analysis [33]. MOF frameworks is of great importance for rational design In addition to the local coordinatively undercoordinated of MOF materials with desired specific properties [33– 48]. metal sites created by integrating fragmented linkers with A particularly elegant way to introduce defects into MOFs one coupling unit missing (type A: mCUS, see Fig. 5), lattice is by use of “defective” linkers [33, 38, 45]. By adjusting defects corresponding to the complete absence of metal ions the concentration of these modified linkers relative to the (type B: node vacancies) could be formed by raising the dop- regular ones the defect concentration can be precisely tuned. ing concentration of defect linkers in DEMOFs. The coex- Such DEMOFs are of a more complex nature compared to istence of defects of both types A and B in Cu–DEMOFs the (more or less) “defect-free” reference materials due to was demonstrated by the combined UHV-FTIRS and XPS the structural heterogeneity resulting from the incorpora- approach [113]. The node vacancies are directly related to tion of the defect linkers or metal ions. A comprehensive the formation of functionalized mesopores, or large-scale experimental characterization in conjunction with theory is defects, in DEMOFs (Fig. 1) [33]. Hupp and coworkers required for a fundamental understanding of the defects in have reported that the introduction of node vacancies (type DEMOFs. In the case of HKUST-1 ([Cu btc ]; Cu-BTC), B defects) into HKUST-1 can finely tune the sorption prop- 3 2 Marx et al. demonstrated defect engineering of CUS via the erties of MOFs [114]. These results revealed the structural solvothermal synthesis with carefully chosen fragmented modulations in DEMOFs at two different length scales in a linkers [38]. In the resulting framework, the trivalent single step, which overcame restrictions of active site speci- 3− btc linker was partially replaced by divalent pyridine- ficity and the confined coordination spaces at the isolated, 2− 3,5-dicarboxylate (pydc ). Such linker substitution was single metal centers. expected to yield reduced Cu CUS at the defect-modified The multivariate nature of DEMOFs represents a new paddlewheel unit. However, the expected change of the oxi- dimension of tailoring functions. In catalysis, both pristine dation state for the copper species was not detected based on and mixed-linker Cu–MOFs showed high catalytic activity the XANES and EXAFS results in Ref. [38]. It is worth not- toward low-temperature hydroxylation of aromatic com- ing that the pristine HKUST-1, in the form of both powders pounds, while the product selectivity was significantly modi- 2− [33, 87] and thin films (SURMOFs) [88], features intrinsi- fied in the presence of pydc linkers [38]. We have further cally reduced Cu sites as the minority species, the amount investigated CO oxidation and alcohol oxidation reactions of which depends on the synthesis, oxidative or reductive within defect-engineered HKUST-1 by IR spectroscopy. treatment, and the activation conditions. Whereas the reduced Cu species are inactive for the low- Fischer and coauthors reported a series of defect-engi- temperature CO oxidation, methanol oxidation occurs at + 2+ neered HKUST-1 via systematic and controlled framework mixed-valence Cu /Cu metal nodes (mCUS), indicating incorporation of various types of defect linkers Lx (L1-L4, special catalytic properties of DEMOFs due to the coexist- see Fig. 4a) using the mixed-linker solid-solution approach ence of low-coordinated Cu CUS (i.e., more electron-rich 2− as a novel synthesis strategy [33]. To gain more detailed sites) and the adjacent defect linkers (pydc ) as functional- insights into the local environments of the mCUS, UHV- ized groups [33]. FTIR spectroscopy was employed to monitor the chemisorp- The same kind of defect engineering has been reported for tion and thermal desorption of CO on different DEMOFs the mixed-valence [Ru btc ] structural analogue of HKUST- 3 2 (Fig. 4). A large number of Cu-related CO bands were 1, where defects were introduced in a controlled manner by a observed which varied in shape and intensity depending on mixed-component (native btc and defect linkers) solid-solu- the nature and density of the defect linkers L1–L4. These tion approach to yield Ru–DEMOFs [36, 37]. The high-level findings revealed the existence of copper species with vari- spectroscopic characterization using primarily UHV-FTIRS ous chemical and structural environments. The assignment and X-ray based techniques (XPS, XANES, XRD) demon- of the CO vibrations was assisted by quantum mechanical/ strated the successful incorporation of various defect linkers molecular mechanical (QM/MM) calculations. The com- that, however, did not reduce the overall integrity and robust- bined results from UHV-FTIRS, XPS, and theory provided ness of the framework in a substantial way [36, 37]. Depend- solid evidence for the simultaneous and controllable modi- ing on the nature and concentration of fragmented linkers, fication of the electronic properties and the proximate coor - both defects of type A and type B (Fig. 5) were detected. δ+ dination space at the metal centers (mCUS) upon incorpo- The type A defects feature reduced R u (0 < δ < 2) sites at ration of defect linkers (see Fig. 4c) [33]. The doping of the modified metal nodes resulting from the fragmented or HKUST-1 with Lx led to the formation of reduced Cu / missing linkers. The formation of node vacancies (defects 2+ Cu paddlewheel units (nodes) with lowered coordination B) was facilitated by the doping with 5-X-isophthalic acids 1 3 Chemical Reactions at Isolated Single-Sites Inside Metal–Organic Frameworks 2207 + 2+ Fig. 4 A Defect Linker concept for DEMOFs: illustration of increas- mixed valence defect Cu /Cu (btc) (pydc) being typical for sample 2− 3− 2− ing defect degree by Lx incorporation, i.e. btc /Lx exchange. DEMOFs (L4) is shown and energetically feasible binding modes for The defect linkers L1–L3 were chosen as benzene-1,3-dicarboxylates one to three coordinated (adsorbed) CO molecules are given (only 2− with various functional groups at 5-position (L1: nidc , –NO ; L2: the QM system is shown for clarity, Cu, brown; C, black; O, red; N, 2− 2− cydc ; –CN; L3: h ydc , –OH) and L4 was pyridine-3,5-dicarbox- blue; H, white) together with computed (scaled) CO stretching nor- 2− −1 ylate (pydc ). B UHV-FTIR spectra obtained after exposing repre- mal mode frequencies (cm ). (e) For comparison the defect is shown sentative DEMOF samples ([Cu (btc) (Lx) ]) with different defect in a close-up, indicating the embedding of the QM system in the MM 3 2−d d linkers L1–L4 to various amounts of CO at 90 K. C QM/MM com- environment. Reproduced with permission from Ref. [33]. Copyright puted binding modes of CO. (a–d) The QM/MM model for a local 2014 American Chemical Society 1 3 2208 Y. Wang, C. Wöll work [36, 37] revealed that the Ru–DEMOFs, synthesized by controlled incorporation of different kinds of defect link - ers, exhibited unusual reactivity for the CO conversion to CO in a dark environment. This reaction does not occur at the “defect-free” Ru-HKUST-1, as supported by the UHV- FTIRS data (Fig. 6) which showed only C O -related IR −1 12 −1 13 bands at 2335 cm ( CO ) and 2272 cm ( CO ). How- 2 2 2− ever, the introduction of pydc defect linkers led to the −1 appearance of low-frequency bands at 2040 and 2000 cm δ+ assigned to CO bound to modified Ru CUS, which were accompanied by a gradual decrease of CO signals. These findings led to the conclusion that the low-temperature (90 K) conversion of C O to CO is driven by strong interac- δ+ tions with reduced R u CUS (i.e., more electron-rich sites) in Ru–DEMOFs. As a result, the enhanced charge transfer from Ru3d to the C O 2π antibonding orbital can facilitate 2 u δ− the formation of chemisorbed C O species that may act as an intermediate to finally give rise to CO. The reactivity Fig. 5 Scheme of different defect types in the [M (BTC) ] (HKUST- of Ru–DEMOFs toward the C O conversion depended not 3 2 1, M = Cu, Ru) family as well as the regular paddlewheel units. The δ+ only on the concentration of reduced Ru , but also on the purple sphere in defect type B stands for a vacancy of the missing nature of defect linkers. The pydc linkers further promoted metal node. Reproduced with permission from Ref. [113]. Copyright the activation of CO due to the presence of basic pyridyl 2017 John Wiley and Sons δ+ N sites in proximity to the reactive Ru mCUS (possible formation of pyridyl N O species [121]), while the 5-OH- (5-X-ip, X = OH, H, NH , Br) linkers where the functional ip-doped Ru–DEMOFs showed much lower reactivity as groups X are much smaller than carboxylate or non-coordi- compared to pydc-doped materials [37]. nating groups (e.g., H). The presence of type B defects in Furthermore, the pydc-modified Ru–DEMOFs, pre- Ru–DEMOFs led to enhanced porosity yielding mesopores, treated with hydrogen at 423 K, exhibited dramatically as was observed for Cu–DEMOFs (see Fig. 1) [33]. enhanced activity and selectivity for olefin hydrogenation MOF-based materials have shown great competency for versus the competing isomerization side reaction [36]. the photocatalytic or electrocatalytic reduction of CO to This outcome was attributed to the efficient formation of CO and other value-added chemicals [115–120]. Our recent Ru–H species via a heterolytic, base-assisted activation δ+ Fig. 6 a UHV-FTIR spectra (the regions of C O and CO vibrations) ing reduced and lower-coordinated Ru reactive centers and func- obtained after exposing the parent and defect-engineered Ru–MOFs tionalized defect linkers. Reproduced with permission from Ref. [36]. to CO at 90 K. b Structure of the defect-engineered Ru–MOFs show- Copyright 2014 John Wiley and Sons 1 3 Chemical Reactions at Isolated Single-Sites Inside Metal–Organic Frameworks 2209 of dihydrogen at the cooperative active centers including potential to be similarly modified in a controlled manner δ+ 2− reduced Ru mCUS and with the adjacent p ydc serving by the choice of the functionalized defect linkers. as a suitable base ligand. The Ru–H species were iden- tified by the characteristic vibrations at 1956–1975 and 2.3 Mixed‑Metal DEMOFs: Metal Node Engineering −1 2057–2076 cm [36]. The proposed reaction mechanism is described in Fig. 7, where the formation of Ru–H is Along with the linker modification in DEMOFs as discussed most likely the rate-determining step [36]. above, the chemical nature of MOF materials can also be The simultaneous presence of two types of defects A precisely tuned by partial metal substitution at framework and B markedly affected the catalytic activities of 5-X- nodes. The latter approach has been employed to synthe- ip (X = OH, H, NH , Br) engineered Ru–DEMOFs [37]. size mixed-metal DEMOFs with the partial substitution of δ+ 2+ 2+ The reduced Ru sites (type A) were responsible for the intrinsic Cu centers in HKUST-1 by Zn and other met- enhanced catalytic performance for ethylene dimerization als of 3d-row (Mn, Fe, Co) that have similar effective ionic 2+ due to the redox properties of Ru mCUS, as observed for radii and are thus closely related with Cu in coordination RhCa-X Zeolite catalysts [122]. Regarding the Paar–Knorr chemistry [123, 124]. The corresponding DEMOFs showed pyrrole synthesis, the Ru–DEMOFs showed much higher enhanced selective sorption of O resulting from the incor- catalytic activity for the conversion of phenylamine to poration of second metal ions into the framework [123]. The pyrrole, as compared to the parent Ru–MOF. Again, this doping with metals of the Pd group is of special interest transformation was attributed to the presence of type A due to their novel catalytic activity for numerous reactions. δ+ defects, where the reduced Ru mCUS (single active However, the introduction of metals of the 4d or 5d row is sites) are bound to the O atom of the carbonyl group and more challenging because the presence of these metal ions facilitate nucleophilic attack by the ion-pair of the amino makes 3D crystal formation difficult due to kinetic reasons group of the phenylamine [37]. Interestingly, an increase [125, 126]. in the density of incorporated 5-OH-ip led to a decrease Recently, the mixed metal Pd@[Cu Pdx(btc) ] with 3−x 2 n of the yield of pyrrole [37]. This result could be explained various levels of doping with Pd were obtained via one-pot in terms of the gradual dominance of defects B at higher synthesis [127]. The XPS results provided evidence for the 2+ doping levels; the formation of node vacancies eliminated simultaneous introduction of Pd -doped framework nodes δ+ 0 part of the reactive Ru centers, thus accounting for the and Pd NPs embedded into MOFs. As shown in Fig. 8, reduced catalytic activity of Ru–DEMOFs. three Pd 3d doublets (3d and 3d ) were resolved in the 5/2 3/2 Overall, our results demonstrated the controlled incor- deconvoluted Pd3d core-level spectra. The two doublets poration of various defect linkers into isoreticular Cu- and at 338.9/344.2 eV (Pd1) and 337.9/343.2 eV (Pd2) were 2+ Ru–MOFs (HKUST-1). The structural, electronic, and ascribed to Pd species, revealing the successful incorpo- 2+ reactive properties of Cu–DEMOFs and Ru–DEMOFs ration of Pd into the framework of Cu-HKUST-1 leading varied strongly depending on the density and nature of to the formation of Cu–Pd and/or Pd–Pd paddlewheels. The the fragmented linkers. Other [M (btc) ] compounds have doublet at 335.8/341.0 eV (Pd3) is characteristic for metallic 3 2 Fig. 7 Olefin hydrogena- tion involving base-assisted heterolytic splitting of H over defect-engineered Ru–MOFs. Note that the pydc linker in DEMOFs offers a basic pyridyl- N atom in the proximity of the reactive Ru centers. Reproduced with permission from Ref. [36]. Copyright 2014 John Wiley and Sons 1 3 2210 Y. Wang, C. Wöll Fig. 8 a Deconvoluted XPS data of Pd@[Cu Pd (btc) ] 3−x x 2 n MOFs with various doping levels of Pd in HKUST-1. b Simultaneous incorporation 2+ 2+ 0 of Pd /M nodes and Pd NPs dispersion into MOF. The 2+ Pd sites in such designed MOFs play an important role in enhancing the catalytic activity of the hydrogenation of p-nitrophenol with NaBH to p-aminophenol. Reproduced with permission from Ref. [127]. Copyright 2016 Royal Society of Chemistry Pd species; its relative concentration increased as the dop- predominantly responsible for the observed high catalytic ing level of Pd increased, indicating the simultaneous load- activity [127]. ing of Pd NPs into the framework. Along with the DEMOFs in HKUST-1 topology, intrin- 2+ 0 Both Pd -containing MOFs [128–130] and Pd @MOFs sic and intentionally created atomic-level defects in other [131–134] exhibited superior catalytic performance for typi- types of MOFs (e.g., Zr–MOFs (UiO-66, UiO-67) [45, 47, cal palladium-catalyzed reactions such as the Suzuki C–C 135–138], NU-125 [139], MOF-69 [35], MIL-53 [35]) have coupling and hydrogenation. The Pd@[Cu Pd (btc) ] been the subject of numerous experimental investigations. 3−x x 2 n 2+ MOFs featuring both incorporated Pd nodes and loaded The defects of type A (reduced metal centers with more open Pd NPs show substantially enhanced catalytic activity coordination environments) were generated either by a direct toward the aqueous-phase hydrogenation of p-nitrophenol synthesis strategy or by post-synthesis approaches. In addi- with NaBH to p-aminophenol, as contrasted with the pris- tion, Brozek and Dinca reported the fabrication of a series of tine Cu–MOFs (HKUST-1). Furthermore, it was evident mixed-metal MOF-5 analogues via isomorphous substitution 2+ 2+ that the Pd species play a key role in this reaction and are at the Zn O cornerstone (see Fig. 9), where the Zn species 1 3 Chemical Reactions at Isolated Single-Sites Inside Metal–Organic Frameworks 2211 varied depending on the quality of MOF thin films that could be controlled in a straightforward fashion [142]. As discussed above for MOF powders, the defect-engineered SURMOFs can be fabricated by controlled introduction of defects using different strategies such as fragmented linker incorporation [33, 38], or thermal treatment [39, 143]. It is expected that the intentional creation of defects inside SURMOFs has important consequences for tuning the electronic structure and catalytic properties of MOF materials. 2+ Fig. 9 Isomorphous substitution of Zn by other metal cations at the The lbl method can also be used to fabricate MOF mem- Zn O cornerstone of MOF-5. Reproduced with permission from Ref. branes. The ability to separate different molecules allows [140]. Copyright 2013 American Chemical Society the integration of size-exclusion principles to MOF-based catalysts. The first SURMOF-based monolithic membrane 2+ was fabricated by Shekhah et al. [144] and was reported to were partially replaced by metal cations with the same (Cr , 2+ 2+ 3+ 3+ 3+ Mn, Fe ) or different oxidation states (Ti, V, Cr be well-suited for the separation of small molecules, e.g., H, N CO, CO, CH , as well as other small hydrocarbons. with Cl as counter-ion) [140]. Furthermore, the approach 2 2, 2 4 of partial post-synthetic metal exchange was employed to A more recent study has demonstrated the use of MOF- based membranes for the natural gas purification and high- produce mixed Al/Fe-MIL-53, Zr/Ti-UiO-66 as well as Zr/ Hf-UiO-66 MOFs featuring mixed metal nodes in the frame- value industrial separations such as butane isomers [145]. Furthermore, it has been shown that the unique opportuni- work [141]. Overall, these different types of defects have been shown to account for the high reactivity of MOF cata- ties to functionalize MOFs permits numerous interesting, membrane-related functionalities, including membranes lysts for a number of catalytic reactions [40]. The controlled incorporation of MOFs with defects of different types and where the permeability and selectivity can be switched on by light [146, 147]. As shown in Fig. 11, the photoswitch- concentrations represents a novel approach for the predic- tive rational design of MOF-based single-site catalysts at able SURMOF membrane was fabricated by assembling linkers decorated with photoresponsive azobenzene-side- the atomic level. groups into the framework, where the precise control of the cis/trans azobenzene ratio by controlled irradiation times 3 MOF Thin Films Grown with ultraviolet or visible light allows for a continuous tun- ing of the separation of molecular mixtures [146]. Since this by the Layer‑by‑Layer Method approach can also be applied to fabricate large-area (larger than 20 cm × 20 cm) membranes [148], and also by apply- Employing the lbl or LPE method, established by Wöll and coworkers [59], to fabricate crystalline, monolithic MOF ing spray-methods, it is, in principle, suited for a continuous coating process. thin films, or SURMOFs [65] affords interesting oppor - tunities for MOF applications in catalysis. In addition to With respect to catalysis, a particularly interesting aspect of SURMOFs is the possibility to combine two different providing well-defined SURMOF substrates which can be applied for chemical transformations as observed for MOF types of chemically active MOFs into one multilayer thin film or membrane by using heteroepitaxy. This approach bulk powders, the lbl method can be used to introduce differ - ent types of defects in SURMOFs, e.g. at internal interfaces allows the creation of tandem catalysts where two different catalytically active components can be incorporated into one in hetero-multilayer structures [65]. In addition, interstitial sites can be created by loading guest species, including single, monolithic thin film (or membrane). The close proximity of two different catalytically active metal or oxide NPs or nanoclusters (NCs), inside the parent SURMOF materials. species which can be realized by a programmed lbl approach is important in the context of reaction cascades with short- An instructive example are HKUST-1 SURMOFs grown on an MHDA/Au substrates (see Fig. 10). The experimen- lived intermediates. In addition, a number of different cata- lysts may interfere, e.g., one catalyst affects the action of tal data from UHV-FTIRS and XPS were interpreted using electronic structure calculation and allowed to derive a the other, or leads to decomposition of the second catalyst. Avoiding these unwanted effects can be achieved by anchor - rather consistent picture [88]. The results showed consist- ently the presence of a small amount (~ 4%) of reduced ing the active species within a three-dimensional porous network. As opposed to just mixing the two catalysts in a Cu species in the pristine HKUST-1 thin film. Upon heat- ing, the temperature-induced creation of Cu defects was liquid, embedding the two different catalysts in a MOF will maintain their individual activities. clearly observed (Fig. 10). The density of intrinsic defects 1 3 2212 Y. Wang, C. Wöll Fig. 10 a Schematic drawing of HKUST-1 grown on an MHDA/ Au substrate. b XP spectra of HKUST-1 SURMOF at dif- ferent temperatures. c UHV- IRRAS spectra of CO adsorbed on activated HKUST-1 SURMOF at 110 K. The sample was annealed at 350 and 420 K. Reproduced with permission from Ref. [88]. Copyright 2012 John Wiley and Sons One of the first demonstrations of such tandem catalysts catalyzed by the Mn-porphyrin to yield epoxide as the realized by the lbl approach are porphyrin-based SUR- reactive intermediate. In a second step, the proximally MOFs. In the paper by Hupp and coworkers [149], a two- sited Zn-porphyrin facilitates the insertion of C O into component SURMOF was grown on a correspondingly the epoxide, giving rise to the cyclic carbonate as the final functionalized substrate (see Fig. 12). This hybrid system product (Fig. 12d). comprising two different metallo-porphyrins (ZnMn-RPM) The technological impact of such tandem catalysts can was shown to be active toward the epoxidation of olefin be improved substantially by realizing them in the form of substrates (Mn-porphyrin) and for epoxide opening (Zn- thin membranes through which the reactants are passed. porphyrin). Although this system could not yet be realized This technology will combine size-exclusion properties in the form of a membrane, this tandem SURMOF thin with catalytic activities. A particular advantage of the layer yielded catalytic turnover numbers which were sub- molecular framework-based approach for catalyst design stantially higher than the corresponding bulk MOF materi- is that the influence of the introduction of additional side- als [149]. The reaction studies in this case was a tandem groups to the MOF–ligands on the chemical activities can reaction consisting of first methoxy-styrene epoxidation be explored in a relatively straightforward fashion. In most 1 3 Chemical Reactions at Isolated Single-Sites Inside Metal–Organic Frameworks 2213 Fig. 11 a Schematic illustra- tion of tunable, remote-con- trollable molecular selectivity by a photoswitchable MOF membrane. b SEM cross- section image of the SURMOF membrane on the mesoporous a-Al O . c The structure of 2 3 Cu (AzoBPDC) (AzoBiPyB) 2 2 with the azobenzene groups. The transition between trans and cis states can be tuned by irradiation with 365 and 455 nm light, respectively. Reproduced with permission from Ref. [146]. Copyright 2016 Springer Nature cases, adding additional functionalities (e.g. OH, –NH , We would like to conclude this section on MOF thin films –CH , etc.) to a ligand will not change the overall structure by pointing out that SURMOFs are also well-suited to study of the MOF. transport phenomena occurring in these framework materi- This approach has been used to improve the efficiency als in a systematic fashion. One example are so-called sur- of a UiO-66 based catalyst for phosphate ester hydrolysis, face barriers, which are relevant for most porous materials. where a rate enhancement of up to 20 times was observed for By using a quartz-crystal microbalance (QCM) based setup, UiO-66 after modification by amino (NH ) moieties that act Heinke et al. could demonstrate that in case of HKUST-I, as a proton-transfer agent during the catalysis cycle [150]. these surface-barriers are not an intrinsic property of MOFs The particular advantage of MOFs in this context is the but result from surface imperfections originating from water- ability to integrate functional units into a porous framework induced corrosion [152]. material without changing the overall architecture of the MOF, which allows tuning of the chemical activity without affecting diffusivities, etc.. Additionally, the catalytic perfor - 4 Homochiral MOFs and Enantioselective mance of MOF materials could also be tuned via the incor- Asymmetric Catalysis poration of inorganic groups containing metal centers as side-groups [22]. This procedure was termed post-synthetic Kim and coworkers reported the first homochiral MOF metalation (PSMet) as the additional catalytically-active (POST-1) that catalyzes a transesterification reaction in an metal moieties can only be added post-synthetically [151]. enantioselective manner [153]. Since this seminal work, The same decoration strategies of MOF–ligands also apply homochiral MOFs have been extensively investigated with to MOF thin films, which enable the multifunctional proper - the aim to rationally fabricate and engineer MOFs mate- ties of SURMOFs to be adjusted in a controlled manner (see rials for heterogeneous asymmetric catalysis. These kinds e.g. the photoswitchable SURMOF membrane depicted in of MOFs can be obtained via distinct strategies such as Fig. 11 [146]). introduction of achiral active centers during synthesis, 1 3 2214 Y. Wang, C. Wöll Fig. 12 a The porphyrinic dipyridine pillar used in the construction of the ZnMn- RMP MOF containing a Mn atom, which can be used as an epoxidation catalyst, and b the porphyrinic tetracarboxylic acid strut used to make the 2D sheets of the ZnMn-RPM MOF containing a Zn atom, which can act as an epoxide-opening catalyst. c Crystallographically- derived representation of a unit cell of the ZnMn-RPM framework. d Schematic repre- sentation of tandem catalysis of ZnMn-RPM for the synthesis of cyclic carbonate. Reproduced with permission from Ref. [149]. Copyright 2016 John Wiley and Sons post-synthetic modification of homochiral MOFs, or incor - in Fig. 13, nanosized homochiral titanium oxo-clusters poration of asymmetric catalysts directly into the framework (Ti–MOCs) were embedded into HKUST-1 frameworks by [154–160]. The substantial potential of homochiral MOFs in using the LPE lbl method [170]. The resulting Ti–MOC@ enantioselective asymmetric catalytic reactions has been dis- HKUST-1 metacrystal was quite efficient regarding enan - cussed by a number of different groups [25, 155, 161–166]. tiomer recognition and separation. Although the combina- Tremendous efforts have been dedicated to homochiral tion of enantiomer-selectivity with catalytically activities MOF powder materials. However, investigations of the cor- in MOF thin films has not been explored, we consider the responding MOF membranes and thin films (SURMOFs) potential of this direction to be enormous, in particular, are few. Only recently, Wöll, Fischer and coworkers reported when combined with membranes. the fabrication of a series of enantiopure metal-camphorate frameworks (MCamFs) deposited on a quartz crystal micro- balance (QCM) substrate via an in situ LPE lbl approach by 5 Metal and Oxide Nanoparticles Embedded changing the metal nodes and/or linker molecules in succes- within MOFs sive deposition cycles [167–170]. Enantioselectivity with regard to the diffusion of different enantiomers into a MOF In the previous paragraphs, we have demonstrated the great thin film can be modulated by using linkers of different chi- potential of MOFs for catalytic performance and it is far rality [167, 168]. In addition, a thorough study of isoreticu- from being fully exploited. But even more possibilities exist lar chiral SURMOFs with identical stereogenic centers but to add further dimensions to the application of MOFs in different pore dimensions demonstrated that the pore sizes catalysis. A particularly important one is the impregnation must be adjusted to achieve the highest enantioselectivity of MOFs with NCs or NPs. Under mild conditions (tem- in chiral nanoporous materials [169]. Furthermore, chiral perature below 250–550 °C, depending on type of MOF), metal–organic nanoclusters (MOCs) can be loaded into the the porous molecular frameworks are sufficiently stable to achiral MOFs, again, achieving a high selectivity between prevent sintering or agglomeration of embedded, catalyti- the diffusivity of different enantiomers [170]. As shown cally active particles, the most severe problems encountered 1 3 Chemical Reactions at Isolated Single-Sites Inside Metal–Organic Frameworks 2215 inside MOFs accounted for the high catalytic activity for liq- uid-phase aerobic oxidation of alcohols (see Fig. 14d). The nano-sized bimetallic alloys are known to show enhanced catalytic performance in numerous reactions as compared to their monometallic counterparts. However, the exclusive encapsulation of bimetallic NPs with tunable com- positions into MOFs is challenging [174–179]. More recently, the embedding of core–shell PdPt and RuPt nano-alloys into Zr-based MOFs (UiO-66 and its derivatives) was realized by template synthesis [180]. The resulting bimetallic core–shell NPs exhibited substrate specic fi size-selectivity and signifi - cantly enhanced catalytic activity for the hydrogenation of nitrobenzene compared to pure Pt loaded UiO-66 [181]. The catalytic performance of MOF materials can also be tuned in a controllable way by encapsulation of vari- ous metal oxide NPs [182–185]. The surface structure and reactivity of nanostructured ZnO particles, embedded into ZIF-8 via chemical vapor infiltration followed by oxidative annealing, were characterized by UHV-FTIRS using C O as a probe molecule [185]. In contrast to pure ZnO NPs exposing mainly non-polar (10–10) surfaces, the confined ZnO NPs inside ZIF-8 were dominated by polar O–ZnO and Zn–ZnO facets as well as defect sites, which were highly reactive for CO activation. The isolated metal oxides (e.g., ZnO, T iO, Fe O ) stabilized within the MOF matrix 2 2 3 showed enhanced multifunctional (catalytic, magnetic, opti- cal) properties and have promising applications in catalysis, photocatalysis, and other fields such as electronic devices and sensors [182–185]. In comparison to MOF bulk powders, much less informa- tion is available for the loading of MOF thin films (SUR - Fig. 13 a Structure of the R–Ti–MOC clusters. b Schematic presenta- MOFs) with metal or metal oxide NPs. Recently, Wöll and tion of in situ lbl growth of enantiopure Ti–MOC-loaded HKUST-1 coworkers reported the first fabrication of Bi O NPs encap- 2 3 thin film using LPE approach. Reproduced with permission from Ref. sulated into HKUST-1 thin films via a novel approach, in [170]. Copyright 2016 American Chemical Society which bismuth-triphenyl was used to create small bismuth oxide particles into the MOF pores [186]. Also in this case the size of the largest Bi O clusters slightly exceeded that when exploiting the high chemical activity of such small 2 3 particles for chemical transformations. of the MOF pores. The size distribution could be narrowed down substantially and at the same time shifted to lower Several strategies exist with regard to loading metal, metal oxide or other chemically active NPs into the MOFs. One of values by adding amino groups acting as nucleation centers to the MOF linkers. Without changing the MOF architecture, the first papers in this area used metal containing precursors to realize small Pd-clusters embedded in the MOF [171]. In this lattice constant, and topology, these additional amino groups acted as nucleation centers, thus achieving a much narrower case, the liberation of the metal atoms was achieved by either exposure to high pressures of H or by irradiation with light. size distribution. Such bismuth oxide particles are highly active in photocatalysis, as demonstrated by the photodegra- It is noteworthy that the palladium clusters were substantially larger than the pores of the MOFs (Fig. 14 case b) [171]. In a dation of nuclear fast red (NFR, C H NO SNa) dye [186]. 14 8 7 similar manner, Au NPs were loaded into different MOF mate- rials (e.g., ZIFs [172], MOF-5 [173]) and distributed homo- 6 SURMOFs and Electrocatalysis geneously over the MOF matrix matching with the cavities (Fig. 14 case c) as conr fi med by HRTEM observations. The Thin MOF films deposited on an electrode also exhibit size distribution and shape of embedded NPs was controlled by the framework structure and the functional groups at the interesting properties in electrochemistry and electroca- talysis [187, 188]. In particular, monolithic, pinhole-free linkers. The homogeneous distribution of confined Au NPs 1 3 2216 Y. Wang, C. Wöll Fig. 14 Top: three characteristic cases of microstructures for NPs narrow size distribution matching with the cavities and homogene- supported by MOFs. a Particles typically larger than the cavity size ously distributed over the volume of MOF. Bottom: d schematic view with a preferred anchoring close to the outer surface of the MOF. b of liquid phase alcohol oxidation with the Au@ZIF-8 material; Both Particles evenly distributed throughout the volume of the MOF crys- benzyl alcohol (BA) and methyl benzoate (MB) are able to access the tal but still exhibiting a broad size distribution with an average par- pores and can diffuse through the network. Reproduced with permis- ticle size exceeding the dimensions of the pores. c Particles with a sion from Ref. [172]. Copyright 2010 American Chemical Society SURMOFs, MOF thin films prepared using the lbl-process In addition to the demonstration of the suitability of SUR- (see Sect. 3, above) exhibited a great potential with respect MOFs for electrochemistry (see above), exciting properties to electrochemistry [189–191]. Although the application of toward photovoltaics (construction of MOF thin film based SURMOFs, both empty and after loading with electroactive solar cells [193, 194]) have been demonstrated. compounds such as ferrocene, has been quite successful, applications in electrocatalysis have been less common. In a recent paper by Liu, Wöll, Sun, and coworkers [192], 7 Summary and Outlook a monolithic, pinhole-free Re-based SURMOF was grown on a conductive, transparent substrate (fluorinated tin oxide, The selected examples of MOF chemical activity discussed or FTO) and exhibited well-defined electrochemical proper - in this short review clearly demonstrate the great potential ties. As demonstrated by the X-ray diffraction (XRD) data, of these porous framework materials for catalysis. Active the MOF films were highly oriented, with the [001] direc- sites can be introduced into these crystalline coordination tion perpendicular to the substrate. These SURMOFs were networks using a broad variety of strategies, and MOFs can shown to be highly effective in the electrocatalytic conver - be used for catalysis either as powders or in the form of sion of CO to CO. The faradaic efficiency found in these thin films (SURMOFs), with the possibility to also fabricate experiments was astonishingly high, amounting to 93 ± 5%. catalytically active membranes. The combined experimental Furthermore, the current densities which could be achieved and theoretical results presented above for selected systems for these high-quality monolithic coatings were found to provided deep, fundamental insights into the structural, elec- −2 be larger than 2 mA cm , thus exceeding the densities tronic and reactive properties of active sites in pristine and recorded for MOF thin films prepared using other methods defect-engineered MOFs (DEMOFs). Depending on the sys- by at least one order of magnitude. tem, isolated, coordinatively unsaturated metal sites (CUS) Although few applications have so far been reported are either an intrinsic component of the perfect system or for photo-electrocatalysis of MOF thin films (e.g., MOFs can be introduced by e.g. defect engineering or by loading as photosensitizers on T iO nanowires for water splitting with suitable guest species, thus creating the potential to fab- [193]), we also foresee enormous potential in this direction. ricate single-site catalysts [22]. The catalytic performance of 1 3 Chemical Reactions at Isolated Single-Sites Inside Metal–Organic Frameworks 2217 CuI[4,4′,4″,4‴-tetracyanotetraphenylmethane]BF .xC H NO . MOFs can be significantly enhanced by tailoring of organic 4 6 5 2 J Am Chem Soc 112:1546–1554 linkers and/or metal cations via defect-engineering strategies 2. Kitagawa S, Matsuyama S, Munakata M, Emori T (1991) in a controlled manner. The resulting DEMOFs are of highly Synthesis and crystal structures of novel one-dimensional I – I complex nature due to the presence of different types of polymers, [{M(bpen)X} ][M = Cu , X = PF ; M = A g , X = ∞ 6 ClO ; bpen = trans-1,2-bis(2-pyridyl)ethylene] and [{Cu(bpen) defects including mCUS (type A: reduced metal centers with (CO)(CH CN)(PF )} ]. J Chem Soc-Dalton Trans. https ://doi. 3 6 ∞ more open coordination space) and node vacancies (type B: org/10.1039/DT991 00028 69. missing metal centers). The defects of type A, together with 3. Gardner GB, Venkataraman D, Moore JS, Lee S (1995) Spon- the proximate functionalized defect linker, were proven to taneous assembly of a hinged coordination network. Nature 374:792–795 play a key role in the catalytic activity of DEMOFs. The 4. Yaghi OM, Li HL (1995) Hydrothermal synthesis of a metal- chemical and physical properties of MOF materials can be organic framework containing large rectangular channels. J Am further precisely modified by adding organic or metal-con- Chem Soc 117:10401–10402 taining functional groups or by embedding of metal, alloy 5. Riou D, Ferey G (1998) Hybrid open frameworks (Mil-N). Part 3 - crystal structures of the Ht and Lt forms of MIL-7: a new or metal oxide NPs into frameworks. vanadium propylenediphosphonate with an open-framework. MOF-based materials, especially MOF thin films coated influence of the synthesis temperature on the oxidation state on various supports, hold also great promise for the appli- of vanadium within the same structural type. J Mater Chem cation in electrocatalysis as well as in photocatalysis and 8:2733–2735 6. O’Keeffe M, Eddaoudi M, Li HL, Reineke T, Yaghi OM (2000) can be utilized in various environment and energy-related Frameworks for extended solids: geometrical design principles. reactions such as water splitting and CO reduction. J Solid State Chem 152:3–20 Although the unique catalytic activities of MOF and 7. Kitagawa S, Kitaura R, Noro S (2004) Functional porous coor- SURMOF materials for various chemical reactions, a thor- dination polymers. Angew Chem-Int Ed 43:2334–2375 8. Park KS, Ni Z, Cote AP, Choi JY, Huang RD, Uribe-Romo FJ, ough atomic-level understanding of the active centers inside Chae HK, O’Keeffe M, Yaghi OM (2006) Exceptional chemical MOFs has not yet been achieved. Many important issues and thermal stability of zeolitic imidazolate frameworks. Proc (e.g., the structure–activity relationships) remain to be a Natl Acad Sci USA 103:10186–10191 substantial challenge. This lack of information results from 9. Moghadam PZ, Li A, Wiggin SB, Tao A, Maloney AGP, Wood PA, Ward SC, Fairen-Jimenez D (2017) Development of a the structural complexity in pristine and defect-engineered cambridge structural database subset: a collection of metal- MOFs and SURMOFs. Overall, it is mandatory to perform organic frameworks for past, present, and future. Chem Mater comprehensive fundamental studies by combining high- 29:2618–2625 level microscopic (e.g. HRTEM [83]) and spectroscopic 10. Kreno LE, Leong K, Farha OK, Allendorf M, Van Duyne RP, Hupp JT (2012) Metal-organic framework materials as chemical (e.g. vibrational spectroscopy and X-ray based techniques) sensors. Chem Rev 112:1105–1125 characterizations in conjunction with theory. In this context, 11. Li JR, Sculley J, Zhou HC (2012) Metal-organic frameworks for MOF thin films are excellent model systems which allow separations. Chem Rev 112:869–932 the application of standard methods developed in Surface 12. Murray LJ, Dinca M, Long JR (2009) Hydrogen storage in metal- organic frameworks. Chem Soc Rev 38:1294–1314 Science. 13. Corma A, Garcia H, Xamena F (2010) Engineering metal organic frameworks for heterogeneous catalysis. Chem Rev Acknowledgements We acknowledge financial support from the Ger - 110:4606–4655 man Research Foundation (DFG), as well as from the “Science and 14. Ferey G (2008) Hybrid porous solids: past, present, future. Chem Technology of Nanosystems” Programme (Project No. 432202). Soc Rev 37:191–214 15. Cohen SM (2012) Postsynthetic methods for the functionalization Open Access This article is distributed under the terms of the Crea- of metal-organic frameworks. Chem Rev 112:970–1000 tive Commons Attribution 4.0 International License (http://creat iveco 16. Long JR, Yaghi OM (2009) The pervasive chemistry of metal- mmons.or g/licenses/b y/4.0/), which permits unrestricted use, distribu- organic frameworks. Chem Soc Rev 38:1213–1214 tion, and reproduction in any medium, provided you give appropriate 17. Chen BL, Liang CD, Yang J, Contreras DS, Clancy YL, Lobko- credit to the original author(s) and the source, provide a link to the vsky EB, Yaghi OM, Dai S (2006) A microporous metal-organic Creative Commons license, and indicate if changes were made. framework for gas-chromatographic separation of alkanes. Angew Chem-Int Ed 45:1390–1393 18. Bloch ED, Queen WL, Krishna R, Zadrozny JM, Brown CM, Long JR (2012) Hydrocarbon separations in a metal-organic framework with open iron(II) coordination sites. Science References 335:1606–1610 19. Talin AA, Centrone A, Ford AC, Foster ME, Stavila V, Haney P, 1. Hoskins BF, Robson R (1990) Design and Construc - Kinney RA, Szalai V, El Gabaly F, Yoon HP, Leonard F, Allen- tion of a new class of scaffolding-like materials compris- dorf MD (2014) Tunable electrical conductivity in metal-organic ing infinite polymeric frameworks of 3-D-linked molec- framework thin-film devices. Science 343:66–69 ular rods—a reappraisal of the Zn(Cn) and Cd(Cn) 20. Furukawa S, Reboul J, Diring S, Sumida K, Kitagawa S (2014) 2 2 structures and the synthesis and structure of the dia- Structuring of metal-organic frameworks at the mesoscopic/mac- I II mond-related frameworks [N(CH ) ][Cu Zn (CN) ] and roscopic scale. Chem Soc Rev 43:5700–5734 3 4 4 1 3 2218 Y. Wang, C. Wöll 21. Schneemann A, Bloch ED, Henke S, Llewellyn PL, Long JR, 39. Vermoortele F, Bueken B, Le Bars G, Van de Voorde B, Van- Fischer RA (2015) Influence of solvent-like sidechains on the dichel M, Houthoofd K, Vimont A, Daturi M, Waroquier M, adsorption of light hydrocarbons in metal-organic frameworks. Van Speybroeck V, Kirschhock C, De Vos DE (2013) Synthe- Chem-Eur J 21:18764–18769 sis modulation as a tool to increase the catalytic activity of 22. Rogge SMJ, Bavykina A, Hajek J, Garcia H, Olivos-Suarez AI, metal-organic frameworks: the unique case of UiO-66(Zr). J Sepulveda-Escribano A, Vimont A, Clet G, Bazin P, Kapteijn F, Am Chem Soc 135:11465–11468 Daturi M, Ramos-Fernandez EV, Xamena F, Van Speybroeck V, 40. Canivet J, Vandichel M, Farrusseng D (2016) Origin of highly Gascon J (2017) Metal-organic and covalent organic frameworks active metal-organic framework catalysts: defects? defects! as single-site catalysts. Chem Soc Rev 46:3134–3184 Dalton Trans 45:4090–4099 23. Lee J, Farha OK, Roberts J, Scheidt KA, Nguyen ST, Hupp JT 41. Liu YY, Klet RC, Hupp JT, Farha O (2016) Probing the cor- (2009) Metal-organic framework materials as catalysts. Chem relations between the defects in metal-organic frameworks and Soc Rev 38:1450–1459 their catalytic activity by an epoxide ring-opening reaction. 24. Farrusseng D, Aguado S, Pinel C (2009) Metal-organic Chem Commun 52:7806–7809 frameworks: opportunities for catalysis. Angew Chem-Int Ed 42. Slater B, Wang ZR, Jiang SX, Hill MR, Ladewig BP (2017) 48:7502–7513 Missing linker defects in a homochiral metal-organic frame- 25. Yoon M, Srirambalaji R, Kim K (2012) Homochiral metal- work: tuning the chiral separation capacity. J Am Chem Soc organic frameworks for asymmetric heterogeneous catalysis. 139:18322–18327 Chem Rev 112:1196–1231 43. Yuan SA, Zou LF, Qin JS, Li JL, Huang L, Feng LA, Wang XA, 26. Valvekens P, Vermoortele F, De Vos D (2013) Metal-organic Bosch M, Alsalme A, Cagin T, Zhou HC (2017) Construction of frameworks as catalysts: the role of metal active sites. Catal hierarchically porous metal-organic frameworks through linker Sci Technol 3:1435–1445 labilization. Nat Commun 8:10 27. Dhakshinamoorthy A, Garcia H (2014) Metal-organic frame- 44. Park J, Wang ZYU, Sun LB, Chen YP, Zhou HC (2012) Intro- works as solid catalysts for the synthesis of nitrogen-containing duction of functionalized mesopores to metal-organic frame- heterocycles. Chem Soc Rev 43:5750–5765 works via metal-ligand-fragment coassembly. J Am Chem Soc 28. Liu JW, Chen LF, Cui H, Zhang JY, Zhang L, Su CY (2014) 134:20110–20116 Applications of metal-organic frameworks in heterogeneous 45. Wu H, Chua YS, Krungleviciute V, Tyagi M, Chen P, Yildi- supramolecular catalysis. Chem Soc Rev 43:6011–6061 rim T, Zhou W (2013) Unusual and highly tunable missing- 29. Gao C, Wang J, Xu HX, Xiong YJ (2017) Coordination chem- linker defects in zirconium metal-organic framework UiO-66 istry in the design of heterogeneous photocatalysts. Chem Soc and their important effects on gas adsorption. J Am Chem Soc Rev 46:2799–2823 135:10525–10532 30. Huang YB, Liang J, Wang XS, Cao R (2017) Multifunctional 46. Cliffe MJ, Wan W, Zou XD, Chater PA, Kleppe AK, Tucker metal-organic framework catalysts: synergistic catalysis and MG, Wilhelm H, Funnell NP, Coudert FX, Goodwin AL (2014) tandem reactions. Chem Soc Rev 46:126–157 Correlated defect nanoregions in a metal-organic framework. Nat 31. Zhu L, Liu XQ, Jiang HL, Sun LB (2017) Metal-organic Commun 5:8 frameworks for heterogeneous basic catalysis. Chem Rev 47. Gutov OV, Hevia MG, Escudero-Adan EC, Shafir A (2015) 117:8129–8176 Metal-organic framework (MOF) defects under control: insights 32. Wang YM, Wöll C (2017) IR Spectroscopic investigations of into the missing linker sites and their implication in the reactivity chemical and photochemical reactions on metal oxides: bridg- of zirconium-based frameworks. Inorg Chem 54:8396–8400 ing the materials gap. Chem Soc Rev 46:1875–1932 48. Trickett CA, Gagnon KJ, Lee S, Gandara F, Burgi HB, Yaghi OM 33. Fang ZL, Durholt JP, Kauer M, Zhang WH, Lochenie C, Jee (2015) Definitive molecular level characterization of defects in B, Albada B, Metzler-Nolte N, Poppl A, Weber B, Muhler M, UiO-66 crystals. Angew Chem-Int Ed 54:11162–11167 Wang YM, Schmid R, Fischer RA (2014) Structural complex- 49. Kanaizuka K, Haruki R, Sakata O, Yoshimoto M, Akita Y, Kita- ity in metal-organic frameworks: simultaneous modification of gawa H (2008) Construction of highly oriented crystalline sur- open metal sites and hierarchical porosity by systematic doping face coordination polymers composed of copper dithiooxamide with defective linkers. J Am Chem Soc 136:9627–9636 complexes. J Am Chem Soc 130:15778–15779 34. Fang ZL, Bueken B, De Vos DE, Fischer RA (2015) Defect- 50. Zacher D, Shekhah O, Wöll C, Fischer RA (2009) Thin films of engineered metal-organic frameworks. Angew Chem-Int Ed metal-organic frameworks. Chem Soc Rev 38:1418–1429 54:7234–7254 51. Shekhah O, Liu J, Fischer RA, Wöll C (2011) MOF thin films: 35. Ravon U, Savonnet M, Aguado S, Domine ME, Janneau E, existing and future applications. Chem Soc Rev 40:1081–1106 Farrusseng D (2010) Engineering of coordination polymers 52. Betard A, Fischer RA (2012) Metal-organic framework thin films: for shape selective alkylation of large aromatics and the role from fundamentals to applications. Chem Rev 112:1055–1083 of defects. Microporous Mesoporous Mater 129:319–329 53. Bradshaw D, Garai A, Huo J (2012) Metal-organic framework 36. Kozachuk O, Luz I, Xamena F, Noei H, Kauer M, Albada HB, growth at functional interfaces: thin films and composites for Bloch ED, Marler B, Wang YM, Muhler M, Fischer RA (2014) diverse applications. Chem Soc Rev 41:2344–2381 Multifunctional, defect-engineered metal-organic frameworks 54. Otsubo K, Kitagawa H (2014) Metal-organic framework thin with ruthenium centers: sorption and catalytic properties. films with well-controlled growth directions confirmed by X-ray Angew Chem-Int Ed 53:7058–7062 study. APL Mater 2:11 37. Zhang WH, Kauer M, Halbherr O, Epp K, Guo PH, Gonzalez 55. Li WJ, Tu M, Cao R, Fischer RA (2016) Metal-organic frame- MI, Xiao DJ, Wiktor C, Xamena F, Wöll C, Wang YM, Muhler work thin films: electrochemical fabrication techniques and M, Fischer RA (2016) Ruthenium metal-organic frameworks corresponding applications & perspectives. J Mater Chem A with different defect types: influence on porosity, sorption, and 4:12356–12369 catalytic properties. Chem-Eur J 22:14297–14307 56. Zhuang JL, Terfort A, Wöll C (2016) Formation of oriented and 38. Marx S, Kleist W, Baiker A (2011) Synthesis, structural prop- patterned films of metal-organic frameworks by liquid phase epi- erties, and catalytic behavior of Cu-BTC and mixed-linker taxy: a review. Coord Chem Rev 307:391–424 57. Edler KJ, Yang B (2013) Formation of mesostructured thin films Cu-BTC-Pydc in the oxidation of benzene derivatives. J Catal at the air-liquid interface. Chem Soc Rev 42:3765–3776 281:76–87 1 3 Chemical Reactions at Isolated Single-Sites Inside Metal–Organic Frameworks 2219 58. Qiu SL, Xue M, Zhu GS (2014) Metal-organic framework mem- 77. Adil K, Belmabkhout Y, Pillai RS, Cadiau A, Bhatt PM, Assen branes: from synthesis to separation application. Chem Soc Rev AH, Maurin G, Eddaoudi M (2017) Gas/vapour separation using 43:6116–6140 ultra-microporous metal-organic frameworks: insights into the 59. Shekhah O, Wang H, Kowarik S, Schreiber F, Paulus M, Tolan structure/separation relationship. Chem Soc Rev 46:3402–3430 M, Sternemann C, Evers F, Zacher D, Fischer RA, Wöll C (2007) 78. Rubio-Martinez M, Avci-Camur C, Thornton AW, Imaz I, Step-by-step route for the synthesis of metal-organic frameworks. Maspoch D, Hill MR (2017) New synthetic routes towards MOF J Am Chem Soc 129:15118–15119 production at scale. Chem Soc Rev 46:3453–3480 60. Munuera C, Shekhah O, Wang H, Wöll C, Ocal C (2008) The 79. Cao XH, Tan CL, Sindoro M, Zhang H (2017) Hybrid micro-/ controlled growth of oriented metal-organic frameworks on func- nano-structures derived from metal-organic frameworks: prepa- tionalized surfaces as followed by scanning force microscopy. ration and applications in energy storage and conversion. Chem Phys Chem Chem Phys 10:7257–7261 Soc Rev 46:2660–2677 61. Shekhah O, Wang H, Zacher D, Fischer RA, Wöll C (2009) 80. Easun TL, Moreau F, Yan Y, Yang SH, Schroder M (2017) Struc- Growth mechanism of metal-organic frameworks: insights into tural and dynamic studies of substrate binding in porous metal- the nucleation by employing a step-by-step route. Angew Chem- organic frameworks. Chem Soc Rev 46:239–274 Int Ed 48:5038–5041 81. Yu JM, Xie LH, Li JR, Ma YG, Seminario JM, Balbuena PB 62. Shekhah O, Wang H, Paradinas M, Ocal C, Schupbach B, Terfort (2017) CO capture and separations using MOFs: computational A, Zacher D, Fischer RA, Wöll C (2009) Controlling interpen- and experimental studies. Chem Rev 117:9674–9754 etration in metal-organic frameworks by liquid-phase epitaxy. 82. Schoedel A, Li M, Li D, O’Keeffe M, Yaghi OM (2016) Struc- Nat Mater 8:481–484 tures of metal-organic frameworks with rod secondary building 63. Darbandi M, Arslan HK, Shekhah O, Bashir A, Birkner A, units. Chem Rev 116:12466–12535 Wöll C (2010) Fabrication of free-standing ultrathin films of 83. Zhang DL, Zhu YH, Liu LM, Ying XR, Hsiung CE, Sougrat porous metal-organic frameworks by liquid-phase epitaxy and R, Li K, Han Y (2018) Atomic-resolution transmission electron subsequent delamination. Phys Status Solidi-Rapid Res Lett microscopy of electron beam-sensitive crystalline materials. Sci- 4:197–199 ence 359:675 64. Fischer RA, Wöll C (2009) Layer-by-layer liquid-phase epitaxy 84. Chui SSY, Lo SMF, Charmant JPH, Orpen AG, Williams ID of crystalline coordination polymers at surfaces. Angew Chem- (1999) A chemically functionalizable nanoporous material Int Ed 48:6205–6208 [Cu (TMA) (H O) ] . Science 283:1148–1150. 3 2 2 3 n 65. Liu JX, Wöll C (2017) Surface-supported metal-organic frame- 85. Ye JY, Liu CJ (2011) Cu-3(Btc)(2): CO oxidation over MOF work thin films: fabrication methods, applications, and chal- based catalysts. Chem Commun 47:2167–2169 lenges. Chem Soc Rev 46:5730–5770 86. Zhao YG, Padmanabhan M, Gong QH, Tsumori N, Xu Q, Li 66. Falcaro P, Ricco R, Doherty CM, Liang K, Hill AJ, Styles MJ J (2011) CO catalytic oxidation by a metal organic framework (2014) MOF positioning technology and device fabrication. containing high density of reactive copper sites. Chem Commun Chem Soc Rev 43:5513–5560 47:6377–6379 67. Stavila V, Talin AA, Allendorf MD (2014) MOF-based electronic 87. Noei H, Amirjalayer S, Muller M, Zhang XN, Schmid R, Muhler and optoelectronic devices. Chem Soc Rev 43:5994–6010 M, Fischer RA, Wang YM (2012) Low-temperature CO oxida- 68. Stassen I, Burtch N, Talin A, Falcaro P, Allendorf M, Ameloot R tion over Cu-based metal-organic frameworks monitored by (2017) An updated roadmap for the integration of metal-organic using FTIR spectroscopy. ChemCatChem 4:755–759 frameworks with electronic devices and chemical sensors. Chem 88. St Petkov P, Vayssilov GN, Liu JX, Shekhah O, Wang YM, Wöll Soc Rev 46:3185–3241 C, Heine T (2012) Defects in MOFs: a thorough characterization. 69. Yang QH, Xu Q, Jiang HL (2017) Metal-organic frameworks ChemPhysChem 13:2025–2029 meet metal nanoparticles: synergistic effect for enhanced cataly - 89. Haruta M, Kobayashi T, Sano H, Yamada N (1987) Novel gold sis. Chem Soc Rev 46:4774–4808 catalysts for the oxidation of carbon-monoxide at a temperature 70. Kitao T, Zhang YY, Kitagawa S, Wang B, Uemura T (2017) far below 0-degrees-C. Chem Lett 16:405–408 Hybridization of MOFs and polymers. Chem Soc Rev 90. Haruta A (2003) When gold is not noble: catalysis by nanopar- 46:3108–3133 ticles. Chem Rec 3:75–87 71. Chen LY, Luque R, Li YW (2017) Controllable design of tunable 91. Schubert MM, Hackenberg S, van Veen AC, Muhler M, Plzak nanostructures inside metal-organic frameworks. Chem Soc Rev V, Behm RJ (2001) CO oxidation over supported gold catalysts- 46:4614–4630 "inert” and “active” support materials and their role for the oxy- 72. Medishetty R, Zareba JK, Mayer D, Samoc M, Fischer RA (2017) gen supply during reaction. J Catal 197:113–122 Nonlinear optical properties, upconversion and lasing in metal- 92. Freund HJ, Meijer G, Schee ffl r M, Schlogl R, Wolf M (2011) CO organic frameworks. Chem Soc Rev 46:4976–5004 oxidation as a prototypical reaction for heterogeneous processes. 73. Li X, Liu YX, Wang J, Gascon J, Li JS, Van der Bruggen B Angew Chem-Int Ed 50:10064–10094 (2017) Metal-organic frameworks based membranes for liquid 93. Over H, Muhler M (2003) Catalytic Co oxidation over ruthe- separation. Chem Soc Rev 46:7124–7144 nium—bridging the pressure gap. Prog Surf Sci 72:3–17 74. Lustig WP, Mukherjee S, Rudd ND, Desai AV, Li J, Ghosh SK 94. Kramer M, Ulrich SB, Kaskel S (2006) Synthesis and proper- (2017) Metal-organic frameworks: functional luminescent and ties of the metal-organic framework Mo (BTC) (TUDMOF-1). 3 2 photonic materials for sensing applications. Chem Soc Rev J Mater Chem 16:2245–2248. 46:3242–3285 95. Murray LJ, Dinca M, Yano J, Chavan S, Bordiga S, Brown 75. Bobbitt NS, Mendonca ML, Howarth AJ, Islamoglu T, Hupp CM, Long JR (2010) Highly-selective and reversible O bind- JT, Farha OK, Snurr RQ (2017) Metal-organic frameworks for ing in Cr (1,3,5-benzenetricarboxylate) . J Am Chem Soc 3 2 the removal of toxic industrial chemicals and chemical warfare 132:7856–7857. agents. Chem Soc Rev 46:3357–3385 96. Feldblyum JI, Liu M, Gidley DW, Matzger AJ (2011) Recon- 76. Lian XZ, Fang Y, Joseph E, Wang Q, Li JL, Banerjee S, Lol- ciling the discrepancies between crystallographic porosity and lar C, Wang X, Zhou HC (2017) Enzyme-MOF (metal-organic guest access as exemplified by Zn-HKUST-1. J Am Chem Soc framework) composites. Chem Soc Rev 46:3386–3401 133:18257–18263 1 3 2220 Y. Wang, C. Wöll 97. Ferey G, Millange F, Morcrette M, Serre C, Doublet ML, Grene- metal-organic frameworks and its effects on gas uptake proper - che JM, Tarascon JM (2007) Mixed-valence Li/Fe-based metal- ties. Inorg Chem 53:6914–6919 organic frameworks with both reversible redox and sorption 115. S. Diercks C, Liu Y, Cordova K, M. Yaghi O (2018) The role of properties. Angew Chem-Int Ed 46:3259–3263 reticular chemistry in the design of CO reduction catalysts. Nat 98. Combelles C, Ben Yahia M, Pedesseau L, Doublet ML (2011) Mater 17:301–307. Fe-II/Fe-III mixed-valence state induced by Li-insertion into the 116. Wang C, Xie ZG, deKrafft KE, Lin WL (2011) Doping metal-organic-framework MIL53(Fe): a DFT + U study. J Power metal-organic frameworks for water oxidation, carbon diox- Sources 196:3426–3432 ide reduction, and organic photocatalysis. J Am Chem Soc 99. Takaishi S, Hosoda M, Kajiwara T, Miyasaka H, Yamashita M, 133:13445–13454 Nakanishi Y, Kitagawa Y, Yamaguchi K, Kobayashi A, Kita- 117. Ryu UJ, Kim SJ, Lim HK, Kim H, Choi KM, Kang JK (2017) gawa H (2009) Electroconductive porous coordination polymer Synergistic interaction of Re complex and amine functionalized Cu[Cu(pdt) ] composed of donor and acceptor building units. multiple ligands in metal-organic frameworks for conversion of Inorg Chem 48:9048–9050. carbon dioxide. Sci Rep 7:8 100. Kobayashi Y, Jacobs B, Allendorf MD, Long JR (2010) Conduc- 118. Choi KM, Kim D, Rungtaweevoranit B, Trickett CA, Barmanbek tivity, doping, and redox chemistry of a microporous dithiolene- JTD, Alshammari AS, Yang PD, Yaghi OM (2017) Plasmon- based metal-organic framework. Chem Mater 22:4120–4122 enhanced photocatalytic CO conversion within metal organic 101. Noei H, Kozachuk O, Amirjalayer S, Bureekaew S, Kauer M, frameworks under visible light. J Am Chem Soc 139:356–362. Schmid R, Marler B, Muhler M, Fischer RA, Wang YM (2013) 119. Kornienko N, Zhao YB, Kiley CS, Zhu CH, Kim D, Lin S, Chang CO adsorption on a mixed-valence ruthenium metal-organic CJ, Yaghi OM, Yang PD (2015) Metal-organic frameworks for framework studied by UHV-FTIR spectroscopy and DFT calcu- electrocatalytic reduction of carbon dioxide. J Am Chem Soc lations. J Phys Chem C 117:5658–5666 137:14129–14135 102. Xu MC, Noei H, Fink K, Muhler M, Wang YM, Wöll C (2012) 120. Hod I, Sampson MD, Deria P, Kubiak CP, Farha OK, Hupp JT The surface science approach for understanding reactions on (2015) Fe-porphyrin-based metal-organic framework films as oxide powders: the importance of IR spectroscopy. Angew high-surface concentration, heterogeneous catalysts for electro- Chem-Int Ed 51:4731–4734 chemical reduction of CO . ACS Catal 5:6302–6309. 103. Gu ZG, Pfriem A, Hamsch S, Breitwieser H, Wohlgemuth J, 121. Jain SL, Sain B (2002) Ruthenium catalyzed oxidation of tertiary Heinke L, Gliemann H, Wöll C (2015) Transparent films of nitrogen compounds with molecular oxygen: an easy access to metal-organic frameworks for optical applications. Microporous N-oxides under mild conditions. Chem Commun 10:1040–1041 Mesoporous Mater 211:82–87 122. Bass JS, Kevan L (1990) Electron-spin-resonance and elec- 104. Muller K, Fink K, Schottner L, Koenig M, Heinke L, Wöll C tron-spin echo spectroscopic studies of paramagnetic rhodium (2017) Defects as color centers: the apparent color of metal- species produced in RhCa-X zeolite during ethylene dimeriza- 2+ organic frameworks containing Cu -based paddle-wheel units. tion - evidence for a sigma-bonded intermediate. J Phys Chem ACS Appl Mater Interfaces 9:37463–37467. 94:1483–1489 105. Shoaee M, Agger JR, Anderson MW, Attfield MP (2008) Crys- 123. Sava Gallis DF, Parkes MV, Greathouse JA, Zhang XY, Nenoff tal form, defects and growth of the metal organic framework TM (2015) Enhanced O selectivity versus N by partial metal 2 2 Hkust-1 revealed by atomic force microscopy. CrystEngComm substitution in Cu-BTC. Chem Mater 27:2018–2025. 10:646–648 124. Gul-E-Noor F, Jee B, Mendt M, Himsl D, Poppl A, Hartmann 106. Cairns AB, Goodwin AL (2013) Structural disorder in molecular M, Haase J, Krautscheid H, Bertmer M (2012) Formation of framework materials. Chem Soc Rev 42:4881–4893 mixed metal Cu Zn (Btc)(2) frameworks with different zinc 3–X x 2+ 107. Chizallet C, Lazare S, Bazer-Bachi D, Bonnier F, Lecocq V, contents: incorporation of Zn into the metal-organic frame- Soyer E, Quoineaud AA, Bats N (2010) Catalysis of transes- work structure as studied by solid-state NMR. J Phys Chem C terification by a nonfunctionalized metal-organic framework: 116:20866–20873. acido-basicity at the external surface of ZIF-8 probed by FTIR 125. Nickerl G, Stoeck U, Burkhardt U, Senkovska I, Kaskel S and Ab initio calculations. J Am Chem Soc 132:12365–12377 (2014) A catalytically active porous coordination polymer 108. Xamena F, Cirujano FG, Corma A (2012) An Unexpected bifunc- based on a dinuclear rhodium paddle-wheel unit. J Mater Chem tional acid base catalysis in Irmof-3 for Knoevenagel condensa- A 2:144–148 tion reactions. Microporous Mesoporous Mater 157:112–117 126. Teo JM, Coghlan CJ, Evans JD, Tsivion E, Head-Gordon M, 109. Bunck DN, Dichtel WR (2013) Mixed linker strategies for Sumby CJ, Doonan CJ (2016) Hetero-bimetallic metal-organic organic framework functionalization. Chem-Eur J 19:818–827 polyhedra. Chem Commun 52:276–279 110. Park TH, Hickman AJ, Koh K, Martin S, Wong-Foy AG, San- 127. Zhang WH, Chen ZH, Al-Naji M, Guo PH, Cwik S, Halbherr O, ford MS, Matzger AJ (2011) Highly dispersed palladium(II) in a Wang YM, Muhler M, Wilde N, Glaser R, Fischer RA (2016) defective metal-organic framework: application to C–H activa- Simultaneous introduction of various palladium active sites into tion and functionalization. J Am Chem Soc 133:20138–20141 MOF via one-pot synthesis: Pd@Cu Pd (BTC)(2)(N). Dalton 3–X x 111. Diring S, Furukawa S, Takashima Y, Tsuruoka T, Kitagawa S Trans 45:14883–14887. (2010) Controlled multiscale synthesis of porous coordination 128. Xamena F, Abad A, Corma A, Garcia H (2007) MOFs as cata- polymer in nano/micro regimes. Chem Mater 22:4531–4538 lysts: activity, reusability and shape-selectivity of a Pd-contain- 112. Al-Janabi N, Fan XL, Siperstein FR (2016) Assessment of ing MOF. J Catal 250:294–298 2+ 0 MOF’s Quality: quantifying defect content in crystalline porous 129. Schuster S, Klemm E, Bauer M (2012) The Role of Pd /Pd in materials. J Phys Chem Lett 7:1490–1494 hydrogenation by Pd(2-Pymo)(2)(N): an X-ray absorption and 113. Zhang WH, Kauer M, Guo PH, Kunze S, Cwik S, Muhler M, IR spectroscopic study. Chem-Eur J 18:15831–15837 Wang YM, Epp K, Kieslich G, Fischer RA (2017) Impact of 130. Opelt S, Krug V, Sonntag J, Hunger M, Klemm E (2012) synthesis parameters on the formation of defects in HKUST-1. Investigations on stability and reusability of Pd(2-Pymo)(2) Eur J Inorg Chem 2017:925–931 (N) as hydrogenation catalyst. Microporous Mesoporous Mater 114. Barin G, Krungleviciute V, Gutov O, Hupp JT, Yildirim T, 147:327–333 Farha OK (2014) Defect creation by linker fragmentation in 1 3 Chemical Reactions at Isolated Single-Sites Inside Metal–Organic Frameworks 2221 131. Sabo M, Henschel A, Froede H, Klemm E, Kaskel S (2007) Solu- metal-organic frameworks with visible light. Chem-Eur J tion infiltration of palladium into MOF-5: synthesis, physisorp- 23:5434–5438 tion and catalytic properties. J Mater Chem 17:3827–3832 148. Hurrle S, Friebe S, Wohlgemuth J, Wöll C, Caro J, Heinke L 132. Gole B, Sanyal U, Banerjee R, Mukherjee PS (2016) High load- (2017) Sprayable, large-area metal-organic framework films and ing of Pd nanoparticles by interior functionalization of MOFs for membranes of varying thickness. Chem-Eur J 23:2294–2298 heterogeneous catalysis. Inorg Chem 55:2345–2354 149. Beyzavi MH, Vermeulen NA, Zhang KN, So M, Kung CW, 133. Wang C, Zhang HY, Feng C, Gao ST, Shang NZ, Wang Z (2015) Hupp JT, Farha OK (2016) Liquid-phase epitaxially grown Multifunctional Pd@MOF core-shell nanocomposite as highly metal-organic framework thin films for efficient tandem cataly - active catalyst for p-nitrophenol reduction. Catal Commun sis through site-isolation of catalytic centers. ChemPlusChem 72:29–32 81:708–713 134. Yuan BZ, Pan YY, Li YW, Yin BL, Jiang HF (2010) A highly 150. Katz MJ, Moon SY, Mondloch JE, Beyzavi MH, Stephenson CJ, active heterogeneous palladium catalyst for the Suzuki- Hupp JT, Farha OK (2015) Exploiting parameter space in MOFs: Miyaura and Ullmann coupling reactions of aryl chlorides in A 20-fold enhancement of phosphate-ester hydrolysis with UiO- aqueous media. Angew Chem-Int Ed 49:4054–4058 66-NH . Chem Sci 6:2286–2291 135. Oien S, Wragg D, Reinsch H, Svelle S, Bordiga S, Lamberti 151. Evans JD, Sumby CJ, Doonan CJ (2014) Post-synthetic metala- C, Lillerud KP (2014) Detailed structure analysis of atomic tion of metal-organic frameworks. Chem Soc Rev 43:5933–5951 positions and defects in zirconium metal-organic frameworks. 152. Heinke L, Gu ZG, Wöll C (2014) The surface barrier phenom- Cryst Growth Des 14:5370–5372 enon at the loading of metal-organic frameworks. Nat Commun 136. Shearer GC, Chavan S, Ethiraj J, Vitillo JG, Svelle S, Olsbye 5:4562 U, Lamberti C, Bordiga S, Lillerud KP (2014) Tuned to per- 153. Seo JS, Whang D, Lee H, Jun SI, Oh J, Jeon YJ, Kim K (2000) fection: ironing out the defects in metal-organic framework A homochiral metal-organic porous material for enantioselective UiO-66. Chem Mater 26:4068–4071 separation and catalysis. Nature 404:982–986 137. Shearer GC, Chavan S, Bordiga S, Svelle S, Olsbye U, Lillerud 154. Evans OR, Ngo HL, Lin WB (2001) Chiral porous solids KP (2016) Defect engineering: tuning the porosity and compo- based on lamellar lanthanide phosphonates. J Am Chem Soc sition of the metal-organic framework Uio-66 via modulated 123:10395–10396 synthesis. Chem Mater 28:3749–3761 155. Wu CD, Hu A, Zhang L, Lin WB (2005) Homochiral porous 138. Shearer GC, Vitillo JG, Bordiga S, Svelle S, Olsbye U, Lillerud metal-organic framework for highly enantioselective heterogene- KP (2016) Functionalizing the defects: postsynthetic ligand ous asymmetric catalysis. J Am Chem Soc 127:8940–8941 exchange in the metal organic framework UiO-66. Chem Mater 156. Cho SH, Ma BQ, Nguyen ST, Hupp JT, Albrecht-Schmitt TE 28:7190–7193 (2006) A metal-organic framework material that functions as an 139. Karagiaridi O, Vermeulen NA, Klet RC, Wang TC, Moghadam enantioselective catalyst for olefin epoxidation. Chem Commun PZ, Al-Juaid SS, Stoddart JF, Hupp JT, Farha OK (2015) Func- 24:2563–2565 tionalized defects through solvent-assisted linker exchange: 157. Banerjee M, Das S, Yoon M, Choi HJ, Hyun MH, Park SM, Seo synthesis, characterization, and partial postsynthesis elabora- G, Kim K (2009) Postsynthetic modification switches an achi- tion of a metal-organic framework containing free carboxylic ral framework to catalytically active homochiral metal-organic acid moieties. Inorg Chem 54:1785–1790 porous materials. J Am Chem Soc 131:7524–7525 3+ 2+/3+ 2+/3+ 2+ 140. Brozek CK, Dinca M (2013) T i-, V-, Cr-, Mn -, 158. Ma LQ, Falkowski JM, Abney C, Lin WB (2010) A series of iso- 2+ and Fe -substituted MOF-5 and redox reactivity in Cr- and reticular chiral metal-organic frameworks as a tunable platform Fe-MOF-5. J Am Chem Soc 135:12886–12891 for asymmetric catalysis. Nat Chem 2:838–846 141. Kim M, Cahill JF, Fei HH, Prather KA, Cohen SM (2012) Post- 159. Lun DJ, Waterhouse GIN, Telfer SG (2011) A general thermola- synthetic ligand and cation exchange in robust metal-organic bile protecting group strategy for organocatalytic metal-organic frameworks. J Am Chem Soc 134:18082–18088 frameworks. J Am Chem Soc 133:5806–5809 142. Gu ZG, Heinke L, Wöll C, Neumann T, Wenzel W, Li Q, Fink 160. Dang DB, Wu PY, He C, Xie Z, Duan CY (2010) Homochiral K, Gordan OD, Zahn DRT (2015) Experimental and theoretical metal-organic frameworks for heterogeneous asymmetric cataly- investigations of the electronic band structure of metal-organic sis. J Am Chem Soc 132:14321–14323 frameworks of HKUST-1 Type. Appl Phys Lett 107:5 161. Ma LQ, Abney C, Lin WB (2009) Enantioselective catalysis 143. Wang ZB, Sezen H, Liu JX, Yang CW, Roggenbuck SE, Pei- with homochiral metal-organic frameworks. Chem Soc Rev kert K, Froba M, Mavrantonakis A, Supronowicz B, Heine T, 38:1248–1256 Gliemann H, Wöll C (2015) Tunable coordinative defects in 162. Dybtsev DN, Nuzhdin AL, Chun H, Bryliakov KP, Talsi EP, UHM-3 surface-mounted MOFs for gas adsorption and separa- Fedin VP, Kim K (2006) A homochiral metal-organic material tion: a combined experimental and theoretical study. Micropo- with permanent porosity, enantioselective sorption properties, rous Mesoporous Mater 207:53–60 and catalytic activity. Angew Chem-Int Ed 45:916–920 144. Shekhah O, Swaidan R, Belmabkhout Y, du Plessis M, Jacobs 163. Li G, Yu WB, Ni J, Liu TF, Liu Y, Sheng EH, Cui Y (2008) T, Barbour LJ, Pinnau I, Eddaoudi M (2014) The liquid phase Self-assembly of a homochiral nanoscale metallacycle from a epitaxy approach for the successful construction of ultra-thin metallosalen complex for enantioselective separation. Angew and defect-free ZIF-8 membranes: pure and mixed gas trans- Chem-Int Ed 47:1245–1249 port study. Chem Commun 50:2089–2092 164. Nickerl G, Henschel A, Grunker R, Gedrich K, Kaskel S (2011) 145. Liu GP, Chernikova V, Liu Y, Zhang K, Belmabkhout Y, Chiral metal-organic frameworks and their application in asym- Shekhah O, Zhang C, Yi SL, Eddaoudi M, Koros WJ (2018) metric catalysis and stereoselective separation. Chem Ing Tech Mixed matrix formulations with MOF molecular sieving for 83:90–103 key energy-intensive separations. Nat Mater 17:283–289 165. Liu Y, Xuan WM, Cui Y (2010) Engineering homochiral metal- 146. Wang ZB, Knebel A, Grosjean S, Wagner D, Brase S, Wöll organic frameworks for heterogeneous asymmetric catalysis and C, Caro J, Heinke L (2016) Tunable molecular separation by enantioselective separation. Adv Mater 22:4112–4135 nanoporous membranes. Nat Commun 7:7 166. Gu ZG, Zhan CH, Zhang J, Bu XH (2016) Chiral chemistry of 147. Muller K, Knebel A, Zhao FL, Bleger D, Caro J, Heinke metal-camphorate frameworks. Chem Soc Rev 45:3122–3144 L (2017) Switching thin films of azobenzene-containing 1 3 2222 Y. Wang, C. Wöll 167. Liu B, Shekhah O, Arslan HK, Liu JX, Wöll C, Fischer RA 181. Zhang WN, Lu G, Cui CL, Liu YY, Li SZ, Yan WJ, Xing C, (2012) Enantiopure metal-organic framework thin films: ori - Chi YR, Yang YH, Huo FW (2014) A family of metal-organic ented SURMOF growth and enantioselective adsorption. Angew frameworks exhibiting size-selective catalysis with encapsulated Chem-Int Ed 51:807–810 noble-metal nanoparticles. Adv Mater 26:4056–4060 168. Gu ZG, Burck J, Bihlmeier A, Liu JX, Shekhah O, Weidler PG, 182. Lu G, Li SZ, Guo Z, Farha OK, Hauser BG, Qi XY, Wang Y, Azucena C, Wang ZB, Heissler S, Gliemann H, Klopper W, Wang X, Han SY, Liu XG, DuChene JS, Zhang H, Zhang QC, Ulrich AS, Wöll C (2014) Oriented circular dichroism analysis Chen XD, Ma J, Loo SCJ, Wei WD, Yang YH, Hupp JT, Huo of chiral surface-anchored metal-organic frameworks grown by FW (2012) Imparting functionality to a metal-organic framework liquid-phase epitaxy and upon loading with chiral guest com- material by controlled nanoparticle encapsulation. Nat Chem pounds. Chem-Eur J 20:9879–9882 4:310–316 169. Gu ZG, Grosjean S, Brase S, Wöll C, Heinke L (2015) Enanti- 183. Zhan WW, Kuang Q, Zhou JZ, Kong XJ, Xie ZX, Zheng LS oselective adsorption in homochiral metal-organic frameworks: (2013) Semiconductor@metal-organic framework core-shell the pore size influence. Chem Commun 51:8998–9001 heterostructures: a case of ZnO@ZIF-8 nanorods with selective 170. Gu ZG, Fu H, Neumann T, Xu ZX, Fu WQ, Wenzel W, Zhang photoelectrochemical response. J Am Chem Soc 135:1926–1933 L, Zhang J, Wöll C (2016) Chiral porous metacrystals: employ- 184. Li XY, Pi YH, Hou QQ, Yu H, Li Z, Li YW, Xiao J (2018) Amor- ing liquid-phase epitaxy to assemble enantiopure metal-organic phous TiO @NH -MIL-125(Ti) homologous MOF-encapsulated 2 2 nanoclusters into molecular framework pores. ACS Nano heterostructures with enhanced photocatalytic activity. Chem 10:977–983 Commun 54:1917–1920 171. Hermes S, Schroter MK, Schmid R, Khodeir L, Muhler M, 185. Esken D, Noei H, Wang YM, Wiktor C, Turner S, Van Tendeloo Tissler A, Fischer RW, Fischer RA (2005) Metal@Mof: load- G, Fischer RA (2011) Zno@Zif-8: stabilization of quantum ing of highly porous coordination polymers host lattices by confined ZnO nanoparticles by a zinc methylimidazolate frame- metal organic chemical vapor deposition. Angew Chem-Int Ed work and their surface structural characterization probed by CO 44:6237–6241 adsorption. J Mater Chem 21:5907–5915. 172. Esken D, Turner S, Lebedev OI, Van Tendeloo G, Fischer RA 186. Guo W, Chen Z, Yang CW, Neumann T, Kuebel C, Wenzel W, (2010) Au@ZIFs: stabilization and encapsulation of cavity-size Welle A, Pfleging W, Shekhah O, Wöll C, Redel E (2016) Bi O 2 3 matching gold clusters inside functionalized zeolite imidazolate nanoparticles encapsulated in surface mounted metal-organic frameworks, Zifs. Chem Mater 22:6393–6401 framework thin films. Nanoscale 8:6468–6472 173. Muller M, Turner S, Lebedev OI, Wang YM, van Tendeloo G, 187. Domenech A, Garcia H, Domenech-Carbo MT, Xamena F (2007) Fischer RA (2011) Au@MOF-5 and Au/MOx@MOF-5 (M = Electrochemistry of metal-organic frameworks: a description Zn, Ti; X = 1, 2): preparation and microstructural characterisa- from the voltammetry of microparticles approach. J Phys Chem tion. Eur J Inorg Chem 2011:1876–1887 C 111:13701–13711 174. Hermannsdorfer J, Friedrich M, Miyajima N, Albuquerque RQ, 188. Babu KF, Kulandainathan MA, Katsounaros I, Rassaei L, Bur- Kummel S, Kempe R (2012) Ni/Pd@Mil-101: synergistic cataly- rows AD, Raithby PR, Marken F (2010) Electrocatalytic activ- sis with cavity-conform Ni/Pd nanoparticles. Angew Chem-Int ity of basolite (Tm) F300 metal-organic-framework structures. Ed 51:11473–11477 Electrochem Commun 12:632–635 175. Zhu QL, Li J, Xu Q (2013) Immobilizing metal nanoparticles to 189. Dragasser A, Shekhah O, Zybaylo O, Shen C, Buck M, Wöll C, metal-organic frameworks with size and location control for opti- Schlettwein D (2012) Redox mediation enabled by immobilised mizing catalytic performance. J Am Chem Soc 135:10210–10213 centres in the pores of a metal-organic framework grown by liq- 176. Huang YB, Zhang YH, Chen XX, Wu DS, Yi ZG, Cao R (2014) uid phase epitaxy. Chem Commun 48:663–665 Bimetallic alloy nanocrystals encapsulated in ZIF-8 for synergis- 190. Mugnaini V, Tsotsalas M, Bebensee F, Grosjean S, Shahnas A, tic catalysis of ethylene oxidative degradation. Chem Commun Brase S, Lahann J, Buck M, Wöll C (2014) Electrochemical 50:10115–10117 investigation of covalently post-synthetic modified surgel coat- 177. Zhou JJ, Wang P, Wang CX, Goh YT, Fang Z, Messersmith ings. Chem Commun 50:11129–11131 PB, Duan HW (2015) Versatile core-shell nanoparticle@metal- 191. Liu JX, Paradinas M, Heinke L, Buck M, Ocal C, Mugnaini organic framework nanohybrids: exploiting mussel-inspired V, Wöll C (2016) Film quality and electronic properties of a polydopamine for tailored structural Integration. ACS Nano surface-anchored metal-organic framework revealed by using a 9:6951–6960 multi-technique approach. ChemElectroChem 3:713–718 178. Chen LY, Chen XD, Liu HL, Li YW (2015) Encapsulation of 192. Ye L, Liu JX, Gao Y, Gong CH, Addicoat M, Heine T, Wöll C, mono- or bimetal nanoparticles inside metal-organic frame- Sun LC (2016) Highly oriented MOF thin film-based electro- works via in situ incorporation of metal precursors. Small catalytic device for the reduction of CO to CO exhibiting high 11:2642–2648 faradaic efficiency. J Mater Chem A 4:15320–15326. 179. Rosler C, Esken D, Wiktor C, Kobayashi H, Yamamoto T, Mat- 193. Zhang LP, Cui P, Yang HB, Chen JZ, Xiao FX, Guo YY, Liu Y, sumura S, Kitagawa H, Fischer RA (2014) Encapsulation of Zhang WN, Huo FW, Liu B (2016) Metal-organic frameworks as bimetallic nanoparticles into a metal-organic framework: prepa- promising photosensitizers for photoelectrochemical water split- ration and microstructure characterization of Pd/Au@ZIF-8. Eur ting. Adv Sci 3:6 J Inorg Chem 2014:5514–5521 194. Liu JX, Zhou WC, Liu JX, Howard I, Kilibarda G, Schlabach S, 180. Rosler C, Dissegna S, Rechac VL, Kauer M, Guo PH, Turner S, Coupry D, Addicoat M, Yoneda S, Tsutsui Y, Sakurai T, Seki Ollegott K, Kobayashi H, Yamamoto T, Peeters D, Wang YM, S, Wang ZB, Lindemann P, Redel E, Heine T, Wöll C (2015) Matsumura S, Van Tendeloo G, Kitagawa H, Muhler M, Xamena Photoinduced charge-carrier generation in epitaxial MOF thin F, Fischer RA (2017) Encapsulation of bimetallic metal nano- films: high efficiency as a result of an indirect electronic band particles into robust zirconium-based metal-organic frameworks: gap? Angew Chem-Int Ed 54:7441–7445 evaluation of the catalytic potential for size-selective hydrogena- tion. Chem-Eur J 23:3583–3594 1 3 http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Catalysis Letters Springer Journals http://www.deepdyve.com/lp/springer-journals/chemical-reactions-at-isolated-single-sites-inside-metal-organic-oeDZmWdDvg

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References (206)

B. Hoskins, R. Robson (1990)
Design and construction of a new class of scaffolding-like materials comprising infinite polymeric frameworks of 3D-linked molecular rods. A reappraisal of the zinc cyanide and cadmium cyanide structures and the synthesis and structure of the diamond-related frameworks [N(CH3)4][CuIZnII(CN)4] and Cu
Journal of the American Chemical Society, 112
Sven Rogge, A. Bavykina, Julianna Hajek, H. García, A. Olivos-Suarez, A. Sepúlveda-Escribano, A. Vimont, G. Clet, P. Bazin, F. Kapteijn, M. Daturi, E. Ramos‐Fernández, F. Xamena, V. Speybroeck, J. Gascón (2017)
Metal–organic and covalent organic frameworks as single-site catalysts
Chemical Society Reviews, 46
Jiamei Yu, Linhua Xie, Jianrong Li, Yuguang Ma, J. Seminario, P. Balbuena (2017)
CO2 Capture and Separations Using MOFs: Computational and Experimental Studies.
Chemical reviews, 117 14
Maryiam Shöâeè, J. Agger, Michael Anderson, M. Attfield (2008)
Crystal form, defects and growth of the metal organic framework HKUST-1 revealed by atomic force microscopy
CrystEngComm, 10
Yangyang Liu, Rachel Klet, J. Hupp, O. Farha (2016)
Probing the correlations between the defects in metal-organic frameworks and their catalytic activity by an epoxide ring-opening reaction.
Chemical communications, 52 50
K. Edler, Bin Yang (2013)
Formation of mesostructured thin films at the air-liquid interface.
Chemical Society reviews, 42 9
S. Jain, B. Sain (2002)
Ruthenium catalyzed oxidation of tertiary nitrogen compounds with molecular oxygen: an easy access to N-oxides under mild conditions.
Chemical communications, 10
I. Stassen, N. Burtch, A. Talin, P. Falcaro, M. Allendorf, R. Ameloot (1970)
Reports of Meetings
Medicine, Science and the Law, 10
S. Hermes, M. Schröter, R. Schmid, L. Khodeir, M. Muhler, A. Tissler, R. Fischer, R. Fischer (2005)
Metal@MOF: loading of highly porous coordination polymers host lattices by metal organic chemical vapor deposition.
Angewandte Chemie, 44 38
W. Guo, Zhi Chen, Chengwu Yang, T. Neumann, C. Kübel, W. Wenzel, A. Welle, Wilhelm Pfleging, O. Shekhah, C. Wöll, E. Redel (2016)
Bi₂O₃ nanoparticles encapsulated in surface mounted metal-organic framework thin films.
Nanoscale, 8 12
Greig Shearer, J. Vitillo, S. Bordiga, S. Svelle, U. Olsbye, K. Lillerud (2016)
Functionalizing the Defects: Postsynthetic Ligand Exchange in the Metal Organic Framework UiO-66
Chemistry of Materials, 28
Petko Petkov, G. Vayssilov, Jinxuan Liu, O. Shekhah, Yuemin Wang, C. Wöll, T. Heine (2012)
Defects in MOFs: a thorough characterization.
Chemphyschem : a European journal of chemical physics and physical chemistry, 13 8
Chui, Lo, Charmant, Orpen, Williams (1999)
A chemically functionalizable nanoporous material
Science, 283 5405
WenHua Zhang, Max Kauer, Olesia Halbherr, Konstantin Epp, P. Guo, Miguel Gonzalez, D. Xiao, C. Wiktor, Francesc Xamena, C. Wöll, Yuemin Wang, M. Muhler, R. Fischer (2016)
Ruthenium Metal-Organic Frameworks with Different Defect Types: Influence on Porosity, Sorption, and Catalytic Properties.
Chemistry, 22 40
D. Lun, Geoffrey Waterhouse, S. Telfer (2011)
A general thermolabile protecting group strategy for organocatalytic metal-organic frameworks.
Journal of the American Chemical Society, 133 15
A. Dragässer, O. Shekhah, Olexandra Zybaylo, Cai Shen, M. Buck, C. Wöll, D. Schlettwein (2012)
Redox mediation enabled by immobilised centres in the pores of a metal-organic framework grown by liquid phase epitaxy.
Chemical communications, 48 5
Jinxuan Liu, C. Wöll (2017)
Surface-supported metal-organic framework thin films: fabrication methods, applications, and challenges.
Chemical Society reviews, 46 19
Nadeen Al-Janabi, Xiaolei Fan, F. Siperstein (2016)
Assessment of MOF's Quality: Quantifying Defect Content in Crystalline Porous Materials.
The journal of physical chemistry letters, 7 8
Carl Brozek, M. Dincǎ (2013)
Reactivity in Cr- and Fe-MOF‑5
J. Feldblyum, Ming Liu, D. Gidley, A. Matzger (2011)
Reconciling the discrepancies between crystallographic porosity and guest access as exemplified by Zn-HKUST-1.
Journal of the American Chemical Society, 133 45
K. Adil, Y. Belmabkhout, Renjith Pillai, A. Cadiau, P. Bhatt, Ayalew Assen, G. Maurin, M. Eddaoudi (2017)
Gas/vapour separation using ultra-microporous metal-organic frameworks: insights into the structure/separation relationship.
Chemical Society reviews, 46 11
Banglin Chen, C. Liang, Jun Yang, D. Contreras, Yvette Clancy, E. Lobkovsky, O. Yaghi, S. Dai (2006)
A microporous metal-organic framework for gas-chromatographic separation of alkanes.
Angewandte Chemie, 45 9
K. Otsubo, H. Kitagawa (2014)
Metal–organic framework thin films with well-controlled growth directions confirmed by x-ray study
APL Materials, 2
J. Seo, D. Whang, Hyoyoung Lee, S. Jun, Jinho Oh, Youngjin Jeon, Kimoon Kim (2000)
A homochiral metal–organic porous material for enantioselective separation and catalysis
Nature, 404
Olga Karagiaridi, Nicolaas Vermeulen, Rachel Klet, Timothy Wang, Peyman Moghadam, S. Al-Juaid, J. Stoddart, J. Hupp, O. Farha, O. Farha (2015)
Functionalized defects through solvent-assisted linker exchange: synthesis, characterization, and partial postsynthesis elaboration of a metal-organic framework containing free carboxylic acid moieties.
Inorganic chemistry, 54 4
D. Bunck, William Dichtel (2013)
Mixed linker strategies for organic framework functionalization.
Chemistry, 19 3
Chuande Wu, A. Hu, Lin Zhang, Wenbin Lin (2005)
A homochiral porous metal-organic framework for highly enantioselective heterogeneous asymmetric catalysis.
Journal of the American Chemical Society, 127 25
C. Chizallet, Sandrine Lazare, Delphine Bazer-Bachi, F. Bonnier, V. Lecocq, Emmanuel Soyer, A. Quoineaud, N. Bats (2010)
Catalysis of transesterification by a nonfunctionalized metal-organic framework: acido-basicity at the external surface of ZIF-8 probed by FTIR and ab initio calculations.
Journal of the American Chemical Society, 132 35
Lu Ye, Jinxuan Liu, Yan Gao, Chenghuan Gong, M. Addicoat, T. Heine, C. Wöll, Licheng Sun (2016)
Highly oriented MOF thin film-based electrocatalytic device for the reduction of CO2 to CO exhibiting high faradaic efficiency
Journal of Materials Chemistry, 4
Chun Wang, Haiyan Zhang, Cheng Feng, Shutao Gao, Ningzhao Shang, Zhi Wang (2015)
Multifunctional Pd@MOF core–shell nanocomposite as highly active catalyst for p-nitrophenol reduction
Catalysis Communications, 72
M. Beyzavi, Nicolaas Vermeulen, Kainan Zhang, Monica So, Monica So, Chung‐Wei Kung, J. Hupp, O. Farha, O. Farha (2016)
Liquid-Phase Epitaxially Grown Metal-Organic Framework Thin Films for Efficient Tandem Catalysis Through Site-Isolation of Catalytic Centers.
ChemPlusChem, 81 8
C. Diercks, Yuzhong Liu, K. Cordova, O. Yaghi (2018)
The role of reticular chemistry in the design of CO2 reduction catalysts
Nature Materials, 17
Mingchun Xu, H. Noei, K. Fink, M. Muhler, Yuemin Wang, C. Wöll (2012)
The surface science approach for understanding reactions on oxide powders: the importance of IR spectroscopy.
Angewandte Chemie, 51 19
Leslie Murray, M. Dincǎ, J. Long (2009)
Hydrogen storage in metal-organic frameworks.
Chemical Society reviews, 38 5
G. Férey (2008)
Hybrid porous solids: past, present, future.
Chemical Society reviews, 37 1
H. Freund, G. Meijer, M. Scheffler, R. Schlögl, Martin Wolf (2011)
CO oxidation as a prototypical reaction for heterogeneous processes.
Angewandte Chemie, 50 43
Jingrui Ye, Chang‐jun Liu (2011)
Cu3(BTC)2: CO oxidation over MOF based catalysts.
Chemical communications, 47 7
BF Hoskins, R Robson (1990)
Design and Construction of a new class of scaffolding-like materials comprising infinite polymeric frameworks of 3-D-linked molecular rods—a reappraisal of the Zn(Cn)2 and Cd(Cn)2 structures and the synthesis and structure of the diamond-related frameworks [N(CH3)4][CuIZnII(CN)4] and CuI[4,4′,4″,4‴-tetracyanotetraphenylmethane]BF4.xC6H5NO2
J Am Chem Soc, 112
Y. Shibuta, S. Sakane, Eisuke Miyoshi, Shinpei Okita, T. Takaki, M. Ohno (2017)
Heterogeneity in homogeneous nucleation from billion-atom molecular dynamics simulation of solidification of pure metal
Nature Communications, 8
Gokhan Barin, V. Krungleviciute, O. Gutov, J. Hupp, T. Yildirim, O. Farha (2014)
Defect creation by linker fragmentation in metal-organic frameworks and its effects on gas uptake properties.
Inorganic chemistry, 53 13
F. Gul-E-Noor, Bettina Jee, Matthias Mendt, Dieter Himsl, A. Pöppl, M. Hartmann, J. Haase, H. Krautscheid, M. Bertmer (2012)
Formation of Mixed Metal Cu3–xZnx(btc)2 Frameworks with Different Zinc Contents: Incorporation of Zn2+ into the Metal–Organic Framework Structure as Studied by Solid-State NMR
Journal of Physical Chemistry C, 116
J. Hermannsdörfer, M. Friedrich, N. Miyajima, R. Albuquerque, S. Kümmel, R. Kempe (2012)
Ni/Pd@MIL-101: synergistic catalysis with cavity-conform Ni/Pd nanoparticles.
Angewandte Chemie, 51 46
H. Noei, Olesia Kozachuk, Saeed Amirjalayer, S. Bureekaew, Max Kauer, R. Schmid, B. Marler, M. Muhler, R. Fischer, Yuemin Wang (2013)
CO Adsorption on a Mixed-Valence Ruthenium Metal–Organic Framework Studied by UHV-FTIR Spectroscopy and DFT Calculations
Journal of Physical Chemistry C, 117
Georg Nickerl, Ulrich Stoeck, U. Burkhardt, I. Senkovska, S. Kaskel (2014)
A catalytically active porous coordination polymer based on a dinuclear rhodium paddle-wheel unit
Journal of Materials Chemistry, 2
S. Furukawa, J. Reboul, Stéphane Diring, K. Sumida, S. Kitagawa (2014)
Structuring of metal-organic frameworks at the mesoscopic/macroscopic scale.
Chemical Society reviews, 43 16
H. Over, M. Muhler (2003)
Catalytic CO oxidation over ruthenium––bridging the pressure gap
Progress in Surface Science, 72
Yan Liu, Weimin Xuan, Yong Cui (2010)
Engineering Homochiral Metal‐Organic Frameworks for Heterogeneous Asymmetric Catalysis and Enantioselective Separation
Advanced Materials, 22
Alexander Schoedel, Mian Li, Dan Li, M. O'Keeffe, O. Yaghi (2016)
Structures of Metal-Organic Frameworks with Rod Secondary Building Units.
Chemical reviews, 116 19
Silvana Hurrle, Sebastian Friebe, J. Wohlgemuth, C. Wöll, J. Caro, L. Heinke (2017)
Sprayable, Large-Area Metal-Organic Framework Films and Membranes of Varying Thickness.
Chemistry, 23 10
Eric Bloch, W. Queen, R. Krishna, Joseph Zadrozny, C. Brown, J. Long (2012)
Hydrocarbon Separations in a Metal-Organic Framework with Open Iron(II) Coordination Sites
Science, 335
S. Schuster, E. Klemm, M. Bauer (2012)
The role of Pd2+/Pd0 in hydrogenation by [Pd(2-pymo)2]n: an X-ray absorption and IR spectroscopic study.
Chemistry, 18 49
K. Park, Z. Ni, A. Côté, Jae Choi, Ru-Dan Huang, F. Uribe-Romo, H. Chae, M. O'Keeffe, O. Yaghi (2006)
Exceptional chemical and thermal stability of zeolitic imidazolate frameworks
Proceedings of the National Academy of Sciences, 103
M. Kim, J. Cahill, Honghan Fei, K. Prather, Seth Cohen (2012)
Postsynthetic ligand and cation exchange in robust metal-organic frameworks.
Journal of the American Chemical Society, 134 43
M. Haruta, Tetsuhiko Kobayashi, H. Sano, N. Yamada (1987)
Novel Gold Catalysts for the Oxidation of Carbon Monoxide at a Temperature far Below 0 °C
Chemistry Letters, 16
Liping Zhang, Ping Cui, Hongbin Yang, Jiazang Chen, Fang‐Xing Xiao, Yuanyuan Guo, Ye Liu, Weina Zhang, F. Huo, B. Liu (2015)
Metal–Organic Frameworks as Promising Photosensitizers for Photoelectrochemical Water Splitting
Advanced Science, 3
Zhenlan Fang, B. Bueken, Dirk De Vos, R. Fischer (2015)
Defect-Engineered Metal–Organic Frameworks
Angewandte Chemie (International Ed. in English), 54
Georg Nickerl, Antje Henschel, Ronny Grünker, Kristina Gedrich, S. Kaskel (2011)
Chiral Metal‐Organic Frameworks and Their Application in Asymmetric Catalysis and Stereoselective Separation
Chemie Ingenieur Technik, 83
M. Sabo, Antje Henschel, H. Fröde, E. Klemm, S. Kaskel (2007)
Solution infiltration of palladium into MOF-5: synthesis, physisorption and catalytic properties
Journal of Materials Chemistry, 17
Jeongyong Lee, O. Farha, John Roberts, K. Scheidt, S. Nguyen, J. Hupp (2009)
Metal-organic framework materials as catalysts.
Chemical Society reviews, 38 5
M. Banerjee, Sunirban Das, M. Yoon, H. Choi, M. Hyun, Se Park, G. Seo, Kimoon Kim (2009)
Postsynthetic modification switches an achiral framework to catalytically active homochiral metal-organic porous materials.
Journal of the American Chemical Society, 131 22
P. Falcaro, R. Riccò, C. Doherty, K. Liang, A. Hill, M. Styles (2014)
MOF positioning technology and device fabrication.
Chemical Society reviews, 43 16
X. Li, Yuxin Liu, Jing Wang, J. Gascón, Jiansheng Li, B. Bruggen (2017)
Metal-organic frameworks based membranes for liquid separation.
Chemical Society reviews, 46 23
Zhengbang Wang, H. Sezen, Jinxuan Liu, Chengwu Yang, Stephanie Roggenbuck, Katharina Peikert, M. Fröba, A. Mavrandonakis, Barbara Supronowicz, T. Heine, H. Gliemann, C. Wöll (2015)
Tunable coordinative defects in UHM-3 surface-mounted MOFs for gas adsorption and separation: A combined experimental and theoretical study
Microporous and Mesoporous Materials, 207
Z. Gu, Cai‐Hong Zhan, Jian Zhang, X. Bu (2016)
Chiral chemistry of metal-camphorate frameworks.
Chemical Society reviews, 45 11
Sabine Opelt, Verena Krug, Jannick Sonntag, M. Hunger, E. Klemm (2012)
Investigations on stability and reusability of [Pd(2-pymo)2]n as hydrogenation catalyst
Microporous and Mesoporous Materials, 147
S. Qiu, Ming Xue, G. Zhu (2014)
Metal-organic framework membranes: from synthesis to separation application.
Chemical Society reviews, 43 16
Jinhee Park, Zhiyong Wang, Lin-Bing Sun, Ying-Pin Chen, Hongcai Zhou (2012)
Introduction of functionalized mesopores to metal-organic frameworks via metal-ligand-fragment coassembly.
Journal of the American Chemical Society, 134 49
Jin‐Liang Zhuang, A. Terfort, C. Wöll (2016)
Formation of oriented and patterned films of metal–organic frameworks by liquid phase epitaxy: A review
Coordination Chemistry Reviews, 307
Yonggang Zhao, M. Padmanabhan, Qihan Gong, Nobuko Tsumori, Qiang Xu, Jing Li (2011)
CO catalytic oxidation by a metal organic framework containing high density of reactive copper sites.
Chemical communications, 47 22
M. Hirscher, B. Panella (2007)
HYDROGEN STORAGE IN METALORGANIC TRAMEWORKS
, 56
A. Talin, A. Centrone, A. Ford, M. Foster, V. Stavila, P. Haney, R. Kinney, V. Szalai, F. Gabaly, H. Yoon, F. Léonard, M. Allendorf (2014)
Tunable Electrical Conductivity in Metal-Organic Framework Thin-Film Devices
Science, 343
Daniel Esken, H. Noei, Yuemin Wang, C. Wiktor, S. Turner, G. Tendeloo, R. Fischer (2011)
ZnO@ZIF-8: stabilization of quantum confined ZnO nanoparticles by a zinc methylimidazolate framework and their surface structural characterization probed by CO2 adsorption
Journal of Materials Chemistry, 21
Jiajing Zhou, Peng Wang, Chenxu Wang, Yi Goh, Z. Fang, P. Messersmith, Hongwei Duan (2015)
Versatile Core-Shell Nanoparticle@Metal-Organic Framework Nanohybrids: Exploiting Mussel-Inspired Polydopamine for Tailored Structural Integration.
ACS nano, 9 7
M. Haruta (2003)
When gold is not noble: catalysis by nanoparticles.
Chemical record, 3 2
Christopher Trickett, Kevin Gagnon, Seungkyu Lee, F. Gándara, H. Bürgi, O. Yaghi (2015)
Definitive molecular level characterization of defects in UiO-66 crystals.
Angewandte Chemie, 54 38
Marta Rubio-Martínez, Ceren Avci-Camur, A. Thornton, I. Imaz, D. Maspoch, M. Hill (2017)
New synthetic routes towards MOF production at scale.
Chemical Society reviews, 46 11
Liqing Ma, C. Abney, Wenbin Lin (2009)
Enantioselective catalysis with homochiral metal-organic frameworks.
Chemical Society reviews, 38 5
A. Bétard, R. Fischer (2012)
Metal-organic framework thin films: from fundamentals to applications.
Chemical reviews, 112 2
F. Xamena, F. Cirujano, A. Corma (2012)
An unexpected bifunctional acid base catalysis in IRMOF-3 for Knoevenagel condensation reactions
Microporous and Mesoporous Materials, 157
T. Park, A. Hickman, Kyoungmoo Koh, Stephen Martin, A. Wong-Foy, M. Sanford, A. Matzger (2011)
Highly dispersed palladium(II) in a defective metal-organic framework: application to C-H activation and functionalization.
Journal of the American Chemical Society, 133 50
R. Medishetty, Jan Zaręba, David Mayer, M. Samoć, R. Fischer (2017)
Nonlinear optical properties, upconversion and lasing in metal-organic frameworks.
Chemical Society reviews, 46 16
Liyu Chen, Xiaodong Chen, Hongli Liu, Yingwei Li (2015)
Encapsulation of Mono- or Bimetal Nanoparticles Inside Metal-Organic Frameworks via In situ Incorporation of Metal Precursors.
Small, 11 22
M. Yoon, Renganathan Srirambalaji, Kimoon Kim (2012)
Homochiral metal-organic frameworks for asymmetric heterogeneous catalysis.
Chemical reviews, 112 2
A. Schneemann, Eric Bloch, Sebastian Henke, P. Llewellyn, J. Long, R. Fischer (2015)
Influence of Solvent-Like Sidechains on the Adsorption of Light Hydrocarbons in Metal-Organic Frameworks.
Chemistry, 21 51
Cheng Wang, Zhigang Xie, K. Dekrafft, Wenbin Lin (2011)
Doping metal-organic frameworks for water oxidation, carbon dioxide reduction, and organic photocatalysis.
Journal of the American Chemical Society, 133 34
T. Easun, F. Moreau, Yong Yan, Sihai Yang, M. Schröder (2017)
Structural and dynamic studies of substrate binding in porous metal-organic frameworks.
Chemical Society reviews, 46 1
Lauren Kreno, Kirsty Leong, O. Farha, M. Allendorf, R. Duyne, J. Hupp (2012)
Metal-organic framework materials as chemical sensors.
Chemical reviews, 112 2
O. Yaghi, Hailian Li (1995)
Hydrothermal Synthesis of a Metal-Organic Framework Containing Large Rectangular Channels
Journal of the American Chemical Society, 117
K. Kanaizuka, R. Haruki, O. Sakata, M. Yoshimoto, Y. Akita, H. Kitagawa (2008)
Construction of highly oriented crystalline surface coordination polymers composed of copper dithiooxamide complexes.
Journal of the American Chemical Society, 130 47
Z. Gu, Hao Fu, T. Neumann, Zonghui Xu, W. Fu, W. Wenzel, Lei Zhang, Jian Zhang, C. Wöll (2016)
Chiral Porous Metacrystals: Employing Liquid-Phase Epitaxy to Assemble Enantiopure Metal-Organic Nanoclusters into Molecular Framework Pores.
ACS nano, 10 1
Bizhen Yuan, Yingyi Pan, Yingwei Li, Biaolin Yin, Huanfeng Jiang (2010)
A highly active heterogeneous palladium catalyst for the Suzuki-Miyaura and Ullmann coupling reactions of aryl chlorides in aqueous media.
Angewandte Chemie, 49 24
L. Heinke, Z. Gu, C. Wöll (2014)
The surface barrier phenomenon at the loading of metal-organic frameworks
Nature Communications, 5
Greig Shearer, S. Chavan, J. Ethiraj, J. Vitillo, S. Svelle, U. Olsbye, C. Lamberti, S. Bordiga, K. Lillerud (2014)
Tuned to Perfection: Ironing Out the Defects in Metal–Organic Framework UiO-66
Chemistry of Materials, 26
William Lustig, S. Mukherjee, Nathan Rudd, Aamod Desai, Jing Li, S. Ghosh (2017)
Metal-organic frameworks: functional luminescent and photonic materials for sensing applications.
Chemical Society reviews, 46 11
Idan Hod, Matthew Sampson, P. Deria, C. Kubiak, O. Farha, J. Hupp (2015)
Fe-Porphyrin-Based Metal–Organic Framework Films as High-Surface Concentration, Heterogeneous Catalysts for Electrochemical Reduction of CO2
ACS Catalysis, 5
O. Shekhah, Hui Wang, Denise Zacher, R. Fischer, C. Wöll (2009)
Growth mechanism of metal-organic frameworks: insights into the nucleation by employing a step-by-step route.
Angewandte Chemie, 48 27
Peyman Moghadam, Aurelia Li, S. Wiggin, Andi Tao, Andrew Maloney, P. Wood, S. Ward, D. Fairen-jimenez (2017)
Development of a Cambridge Structural Database Subset: A Collection of Metal-Organic Frameworks for Past, Present, and Future
Chemistry of Materials, 29
D. Riou, G. Férey (1998)
Hybrid open frameworks (MIL-n). Part 3 Crystal structures of the HT and LT forms of MIL-7 : a new vanadium propylenediphosphonate with an open-framework. Influence of the synthesis temperature on the oxidation state of vanadium within the same structural type
Journal of Materials Chemistry, 8
A. Doménech, H. García, §. Doménech-Carbó, Francesc Llabrés-i-Xamena‡ (2007)
Electrochemistry of Metal−Organic Frameworks: A Description from the Voltammetry of Microparticles Approach
Journal of Physical Chemistry C, 111
S. Kitagawa, R. Kitaura, S. Noro (2004)
Functional porous coordination polymers.
Angewandte Chemie, 43 18
ClO 4 -; bpen = trans-1,2-bis(2-pyridyl)ethylene] and [{Cu(bpen) (CO)(CH 3 CN
O. Gutov, Miguel Hevia, Eduardo Escudero‐Adán, A. Shafir (2015)
Metal-Organic Framework (MOF) Defects under Control: Insights into the Missing Linker Sites and Their Implication in the Reactivity of Zirconium-Based Frameworks.
Inorganic chemistry, 54 17
Liyu Chen, R. Luque, Yingwei Li (2017)
Controllable design of tunable nanostructures inside metal-organic frameworks.
Chemical Society reviews, 46 15
V. Mugnaini, M. Tsotsalas, F. Bebensee, S. Grosjean, A. Shahnas, S. Bräse, J. Lahann, M. Buck, C. Wöll (2014)
Electrochemical investigation of covalently post-synthetic modified SURGEL coatings.
Chemical communications, 50 76
Xiehong Cao, Chaoliang Tan, Melinda Sindoro, Hua Zhang (2017)
Hybrid micro-/nano-structures derived from metal-organic frameworks: preparation and applications in energy storage and conversion.
Chemical Society reviews, 46 10
Bo Liu, O. Shekhah, H. Arslan, Jinxuan Liu, C. Wöll, R. Fischer (2012)
Enantiopure metal-organic framework thin films: oriented SURMOF growth and enantioselective adsorption.
Angewandte Chemie, 51 3
N. Kornienko, Yingbo Zhao, Christopher Kley, Chenhui Zhu, Dohyung Kim, Song Lin, Christopher Chang, O. Yaghi, P. Yang (2015)
Metal-organic frameworks for electrocatalytic reduction of carbon dioxide.
Journal of the American Chemical Society, 137 44
Shuai Yuan, L. Zou, Jun-sheng Qin, Jialuo Li, Lan Huang, Liang Feng, Xuan Wang, Mathieu Bosch, A. Alsalme, T. Çagin, Hongcai Zhou (2017)
Construction of hierarchically porous metal–organic frameworks through linker labilization
Nature Communications, 8
O. Evans, H. Ngo, Wenbin Lin (2001)
Chiral porous solids based on lamellar lanthanide phosphonates.
Journal of the American Chemical Society, 123 42
K. Müller, K. Fink, Ludger Schöttner, Meike Koenig, L. Heinke, C. Wöll (2017)
Defects as Color Centers: The Apparent Color of Metal-Organic Frameworks Containing Cu2+-Based Paddle-Wheel Units.
ACS applied materials & interfaces, 9 42
Z. Gu, L. Heinke, C. Wöll, T. Neumann, W. Wenzel, Qiang Li, K. Fink, O. Gordan, D. Zahn (2015)
Experimental and theoretical investigations of the electronic band structure of metal-organic frameworks of HKUST-1 type
Applied Physics Letters, 107
D. Farrusseng, S. Aguado, C. Pinel (2009)
Metal-organic frameworks: opportunities for catalysis.
Angewandte Chemie, 48 41
Z. Gu, J. Bürck, Angela Bihlmeier, Jinxuan Liu, O. Shekhah, P. Weidler, C. Azucena, Zhengbang Wang, S. Heissler, H. Gliemann, W. Klopper, A. Ulrich, C. Wöll (2014)
Oriented circular dichroism analysis of chiral surface-anchored metal-organic frameworks grown by liquid-phase epitaxy and upon loading with chiral guest compounds.
Chemistry, 20 32
Denise Zacher, O. Shekhah, C. Wöll, R. Fischer (2009)
Thin films of metal-organic frameworks.
Chemical Society reviews, 38 5
Qihao Yang, Qiang Xu, Hai‐Long Jiang (2017)
Metal-organic frameworks meet metal nanoparticles: synergistic effect for enhanced catalysis.
Chemical Society reviews, 46 15
Christoph Rösler, Stefano Dissegna, Víctor Rechac, Max Kauer, P. Guo, S. Turner, Kevin Ollegott, Hirokazu Kobayashi, Tomokazu Yamamoto, D. Peeters, Yuemin Wang, S. Matsumura, G. Tendeloo, H. Kitagawa, M. Muhler, F. Xamena, R. Fischer (2017)
Encapsulation of Bimetallic Metal Nanoparticles into Robust Zirconium-Based Metal-Organic Frameworks: Evaluation of the Catalytic Potential for Size-Selective Hydrogenation.
Chemistry, 23 15
K. Müller, A. Knebel, Fangli Zhao, D. Bléger, J. Caro, L. Heinke (2017)
Switching Thin Films of Azobenzene-Containing Metal-Organic Frameworks with Visible Light.
Chemistry, 23 23
Seth Cohen (2012)
Postsynthetic methods for the functionalization of metal-organic frameworks.
Chemical reviews, 112 2
F. Xamena, A. Abad, A. Corma, H. García (2007)
MOFs as catalysts: Activity, reusability and shape-selectivity of a Pd-containing MOF
Journal of Catalysis, 250
Y. Kobayashi, B. Jacobs, M. Allendorf, J. Long (2010)
Conductivity, Doping, and Redox Chemistry of a Microporous Dithiolene-Based Metal−Organic Framework
Chemistry of Materials, 22
M. Kramer, U. Schwarz, S. Kaskel (2006)
Synthesis and properties of the metal-organic framework Mo3(BTC)2 (TUDMOF-1)
Journal of Materials Chemistry, 16
V. Stavila, A. Talin, M. Allendorf (2014)
MOF-based electronic and opto-electronic devices.
Chemical Society reviews, 43 16
Daliang Zhang, Yihan Zhu, Lingmei Liu, Xiangrong Ying, Chia-En Hsiung, R. Sougrat, Kun Li, Yu Han (2018)
Atomic-resolution transmission electron microscopy of electron beam–sensitive crystalline materials
Science, 359
UnJin Ryu, Sang Kim, Hyung-Kyu Lim, Hyungjun Kim, K. Choi, J. Kang (2017)
Synergistic interaction of Re complex and amine functionalized multiple ligands in metal-organic frameworks for conversion of carbon dioxide
Scientific Reports, 7
Olesia Kozachuk, I. Luz, Francesc Llabrés i Xamena, H. Noei, Max Kauer, H. Albada, Eric Bloch, B. Marler, Yuemin Wang, M. Muhler, R. Fischer (2014)
Multifunctional, defect-engineered metal-organic frameworks with ruthenium centers: sorption and catalytic properties.
Angewandte Chemie, 53 27
Guang Lu, Shaozhou Li, Zhen Guo, O. Farha, B. Hauser, X. Qi, Yi Wang, Xin Wang, Sanyang Han, Xiaogang Liu, J. DuChene, Hua Zhang, Qichun Zhang, Xiaodong Chen, Jan Ma, Say Loo, W. Wei, Yanhui Yang, J. Hupp, F. Huo (2012)
Imparting functionality to a metal-organic framework material by controlled nanoparticle encapsulation.
Nature chemistry, 4 4
MJ Katz, SY Moon, JE Mondloch, MH Beyzavi, CJ Stephenson, JT Hupp, OK Farha (2015)
Exploiting parameter space in MOFs: A 20-fold enhancement of phosphate-ester hydrolysis with UiO-66-NH2
Chem Sci, 6
Jianrong Li, J. Sculley, Hongcai Zhou (2012)
Metal-organic frameworks for separations.
Chemical reviews, 112 2
S. Øien, D. Wragg, H. Reinsch, S. Svelle, S. Bordiga, C. Lamberti, K. Lillerud (2014)
Detailed Structure Analysis of Atomic Positions and Defects in Zirconium Metal‒Organic Frameworks
Crystal Growth & Design, 14
Liqing Ma, J. Falkowski, C. Abney, Wenbin Lin (2010)
A series of isoreticular chiral metal-organic frameworks as a tunable platform for asymmetric catalysis.
Nature chemistry, 2 10
S Kitagawa, S Matsuyama, M Munakata, T Emori (1991)
Synthesis and crystal structures of novel one-dimensional polymers, [{M(bpen)X}∞][M = CuI, X = PF6 –; M = AgI, X = ClO4 –; bpen = trans-1,2-bis(2-pyridyl)ethylene] and [{Cu(bpen)(CO)(CH3CN)(PF6)}∞]
J Chem Soc-Dalton Trans
Gao Li, Weibin Yu, Jia Ni, Taifeng Liu, Yan Liu, Enhong Sheng, Yong Cui (2008)
Self-assembly of a homochiral nanoscale metallacycle from a metallosalen complex for enantioselective separation.
Angewandte Chemie, 47 7
G. Gardner, D. Venkataraman, Jeffrey Moore, Stephen Lee (1995)
Spontaneous assembly of a hinged coordination network
Nature, 374
Yuan-Jun Huang, Yao Zhang, Xuxing Chen, Dongshuang Wu, Z. Yi, R. Cao (2014)
Bimetallic alloy nanocrystals encapsulated in ZIF-8 for synergistic catalysis of ethylene oxidative degradation.
Chemical communications, 50 70
Stéphane Diring, S. Furukawa, Y. Takashima, T. Tsuruoka, S. Kitagawa (2010)
Controlled Multiscale Synthesis of Porous Coordination Polymer in Nano/Micro Regimes
Chemistry of Materials, 22
Jesse Teo, Campbell Coghlan, J. Evans, Ehud Tsivion, M. Head‐Gordon, C. Sumby, C. Doonan (2016)
Hetero-bimetallic metal-organic polyhedra.
Chemical communications, 52 2
M. O'Keeffe, M. Eddaoudi, Hailian Li, T. Reineke, O. Yaghi (2000)
Frameworks for Extended Solids: Geometrical Design Principles
IEEE Journal of Solid-state Circuits, 152
Daniel Esken, S. Turner, O. Lebedev, G. Tendeloo, R. Fischer (2010)
Au@ZIFs: Stabilization and Encapsulation of Cavity-Size Matching Gold Clusters inside Functionalized Zeolite Imidazolate Frameworks, ZIFs
Chemistry of Materials, 22
O. Shekhah, Jinxuan Liu, R. Fischer, C. Wöll (2011)
MOF thin films: existing and future applications.
Chemical Society reviews, 40 2
M O’Keeffe, M Eddaoudi, HL Li, T Reineke, OM Yaghi (2000)
Frameworks for extended solids: geometrical design principles
J Solid State Chem, 152
M. Schubert, S. Hackenberg, A. Veen, M. Muhler, V. Plzak, R. Behm (2001)
CO Oxidation over Supported Gold Catalysts—“Inert” and “Active” Support Materials and Their Role for the Oxygen Supply during Reaction
Journal of Catalysis, 197
Jiewei Liu, Lianfen Chen, H. Cui, Jianyong Zhang, Li Zhang, C. Su (2014)
Applications of metal-organic frameworks in heterogeneous supramolecular catalysis.
Chemical Society reviews, 43 16
Bappaditya Gole, Udishnu Sanyal, R. Banerjee, P. Mukherjee (2016)
High Loading of Pd Nanoparticles by Interior Functionalization of MOFs for Heterogeneous Catalysis.
Inorganic chemistry, 55 5
O. Shekhah, Hui Wang, M. Paradinas, C. Ocal, Björn Schüpbach, A. Terfort, Denise Zacher, R. Fischer, C. Wöll (2009)
Controlling interpenetration in metal-organic frameworks by liquid-phase epitaxy.
Nature materials, 8 6
J. Canivet, Matthias Vandichel, Matthias Vandichel, D. Farrusseng (2016)
Origin of highly active metal-organic framework catalysts: defects? Defects!
Dalton transactions, 45 10
Gongpin Liu, V. Chernikova, Yang Liu, Kuang Zhang, Y. Belmabkhout, O. Shekhah, Chen Zhang, Shouliang Yi, M. Eddaoudi, W. Koros (2018)
Mixed matrix formulations with MOF molecular sieving for key energy-intensive separations
Nature Materials, 17
A. Dhakshinamoorthy, H. García (2014)
Metal-organic frameworks as solid catalysts for the synthesis of nitrogen-containing heterocycles.
Chemical Society reviews, 43 16
J. Long, O. Yaghi (2009)
The pervasive chemistry of metal-organic frameworks.
Chemical Society reviews, 38 5
Jinxuan Liu, Wencai Zhou, Jianxi Liu, I. Howard, G. Kilibarda, S. Schlabach, Damien Coupry, M. Addicoat, S. Yoneda, Yusuke Tsutsui, T. Sakurai, S. Seki, Zhengbang Wang, P. Lindemann, E. Redel, T. Heine, C. Wöll (2015)
Photoinduced Charge-Carrier Generation in Epitaxial MOF Thin Films: High Efficiency as a Result of an Indirect Electronic Band Gap?
Angewandte Chemie, 54 25
H. Noei, Saeed Amirjalayer, Maike Müller, Xiaoning Zhang, R. Schmid, M. Muhler, R. Fischer, Yuemin Wang (2012)
Low‐Temperature CO Oxidation over Cu‐Based Metal–Organic Frameworks Monitored by using FTIR Spectroscopy
ChemCatChem, 4
WenHua Zhang, Max Kauer, P. Guo, S. Kunze, Stefan Cwik, M. Muhler, Yuemin Wang, Konstantin Epp, G. Kieslich, R. Fischer (2017)
Impact of synthesis parameters on the formation of defects in HKUST‐1
European Journal of Inorganic Chemistry, 2017
K. Choi, Dohyung Kim, Bunyarat Rungtaweevoranit, Christopher Trickett, Jesika Barmanbek, A. Alshammari, P. Yang, O. Yaghi (2017)
Plasmon-Enhanced Photocatalytic CO(2) Conversion within Metal-Organic Frameworks under Visible Light.
Journal of the American Chemical Society, 139 1
D. Dybtsev, A. Nuzhdin, Hyungphil Chun, K. Bryliakov, Evgeniy Talsi, V. Fedin, Kimoon Kim (2006)
A homochiral metal-organic material with permanent porosity, enantioselective sorption properties, and catalytic activity.
Angewandte Chemie, 45 6
C. Combelles, M. Yahia, L. Pédesseau, M. Doublet (2011)
FeII/FeIII mixed-valence state induced by Li-insertion into the metal-organic-framework Mil53(Fe): A DFT+U study
Journal of Power Sources, 196
Xizhen Lian, Yu Fang, E. Joseph, Qi Wang, Jialuo Li, Sayanti Banerjee, Christina Lollar, Xuan Wang, Hongcai Zhou (2017)
Enzyme-MOF (metal-organic framework) composites.
Chemical Society reviews, 46 11
A. Cairns, A. Goodwin (2013)
Structural disorder in molecular framework materials.
Chemical Society reviews, 42 12
Maike Müller, S. Turner, O. Lebedev, Yuemin Wang, G. Tendeloo, R. Fischer (2011)
2 ) : Preparation and Microstructural Characterisation
Li Zhu, Xiao-Qin Liu, Hai‐Long Jiang, Linbing Sun (2017)
Metal-Organic Frameworks for Heterogeneous Basic Catalysis.
Chemical reviews, 117 12
R. Fischer, C. Wöll (2009)
Layer-by-layer liquid-phase epitaxy of crystalline coordination polymers at surfaces.
Angewandte Chemie, 48 34
J. Bass, L. Kevan (1990)
Electron spin resonance and electron spin echo spectroscopic studies of paramagnetic rhodium species produced in RhCa-X zeolite during ethylene dimerization: evidence for a .sigma.-bonded intermediate
The Journal of Physical Chemistry, 94
Weina Zhang, Guang Lu, Chenlong Cui, Yayuan Liu, Shaozhou Li, Wenjin Yan, Chong Xing, Y. Chi, Yanhui Yang, F. Huo (2014)
A Family of Metal‐Organic Frameworks Exhibiting Size‐Selective Catalysis with Encapsulated Noble‐Metal Nanoparticles
Advanced Materials, 26
S. Takaishi, Miyuki Hosoda, T. Kajiwara, H. Miyasaka, M. Yamashita, Yasuyuki Nakanishi, Y. Kitagawa, K. Yamaguchi, A. Kobayashi, H. Kitagawa (2009)
Electroconductive porous coordination polymer Cu[Cu(pdt)2] composed of donor and acceptor building units.
Inorganic chemistry, 48 19
Pieterjan Valvekens, F. Vermoortele, D. Vos (2013)
Metal–organic frameworks as catalysts: the role of metal active sites
Catalysis Science & Technology, 3
D. Bradshaw, A. Garai, J. Huo (2012)
Metal-organic framework growth at functional interfaces: thin films and composites for diverse applications.
Chemical Society reviews, 41 6
WenHua Zhang, Zhihao Chen, Majd Al‐Naji, P. Guo, Stefan Cwik, Olesia Halbherr, Yuemin Wang, M. Muhler, N. Wilde, R. Gläser, R. Fischer (2016)
Simultaneous introduction of various palladium active sites into MOF via one-pot synthesis: Pd@[Cu3-xPdx(BTC)2]n.
Dalton transactions, 45 38
Camilla Sharkey, M. Fujimoto, N. Lord, Seunggwan Shin, D. Mckenna, Anton Suvorov, Gavin Martin, S. Bybee (2017)
Overcoming the loss of blue sensitivity through opsin duplication in the largest animal group, beetles
Scientific Reports, 7
Ugo Ravon, Marie Savonnet, S. Aguado, M. Domine, E. Janneau, D. Farrusseng (2010)
Engineering of coordination polymers for shape selective alkylation of large aromatics and the role of defects
Microporous and Mesoporous Materials, 129
Jianxi Liu, M. Paradinas, L. Heinke, M. Buck, C. Ocal, V. Mugnaini, C. Wöll (2016)
Film Quality and Electronic Properties of a Surface‐Anchored Metal‐Organic Framework Revealed by using a Multi‐technique Approach
, 3
Yuan–Biao Huang, Jun Liang, Xusheng Wang, R. Cao (2017)
Multifunctional metal-organic framework catalysts: synergistic catalysis and tandem reactions.
Chemical Society reviews, 46 1
Wenwen Zhan, Q. Kuang, Jianzhang Zhou, Xiang‐Jian Kong, Zhaoxiong Xie, Lan-Sun Zheng (2013)
Semiconductor@metal-organic framework core-shell heterostructures: a case of ZnO@ZIF-8 nanorods with selective photoelectrochemical response.
Journal of the American Chemical Society, 135 5
S. Chui, S. Lo, J. Charmant, A. Orpen, Ian Williams (1999)
A chemically functionalizable nanoporous material (Cu3(TMA)2(H2O)3)n
Science, 283
M. Darbandi, H. Arslan, O. Shekhah, A. Bashir, A. Birkner, C. Wöll (2010)
Fabrication of free‐standing ultrathin films of porous metal‐organic frameworks by liquid‐phase epitaxy and subsequent delamination
physica status solidi (RRL) – Rapid Research Letters, 4
Stefan Marx, W. Kleist, A. Baiker (2011)
Synthesis, structural properties, and catalytic behavior of Cu-BTC and mixed-linker Cu-BTC-PyDC in the oxidation of benzene derivatives
Journal of Catalysis, 281
Takashi Kitao, Yuanyuan Zhang, S. Kitagawa, Bo Wang, T. Uemura (2017)
Hybridization of MOFs and polymers.
Chemical Society reviews, 46 11
Christoph Rösler, Daniel Esken, C. Wiktor, Hirokazu Kobayashi, Tomokazu Yamamoto, S. Matsumura, H. Kitagawa, R. Fischer (2014)
Encapsulation of Bimetallic Nanoparticles into a Metal–Organic Framework: Preparation and Microstructure Characterization of Pd/Au@ZIF‐8
European Journal of Inorganic Chemistry, 2014
Yuemin Wang, C. Wöll (2017)
IR spectroscopic investigations of chemical and photochemical reactions on metal oxides: bridging the materials gap.
Chemical Society reviews, 46 7
Weijin Li, M. Tu, R. Cao, R. Fischer (2016)
Metal–organic framework thin films: electrochemical fabrication techniques and corresponding applications & perspectives
Journal of Materials Chemistry, 4
Benjamin Slater, Zeru Wang, Shanxue Jiang, M. Hill, B. Ladewig (2017)
Missing Linker Defects in a Homochiral Metal-Organic Framework: Tuning the Chiral Separation Capacity.
Journal of the American Chemical Society, 139 50
K. Babu, M. Kulandainathan, I. Katsounaros, Liza Rassaei, Andrew Burrows, P. Raithby, F. Marken (2010)
Electrocatalytic activity of BasoliteTM F300 metal-organic-framework structures
Electrochemistry Communications, 12
G. Férey, F. Millange, M. Morcrette, C. Serre, M. Doublet, J. Greneche, J. Tarascon (2007)
Mixed-valence li/fe-based metal-organic frameworks with both reversible redox and sorption properties.
Angewandte Chemie, 46 18
I. Stassen, N. Burtch, A. Talin, P. Falcaro, M. Allendorf, R. Ameloot (2017)
An updated roadmap for the integration of metal-organic frameworks with electronic devices and chemical sensors.
Chemical Society reviews, 46 11
Qi Zhu, Jun Li, Qiang Xu (2013)
Immobilizing metal nanoparticles to metal-organic frameworks with size and location control for optimizing catalytic performance.
Journal of the American Chemical Society, 135 28
Zhengbang Wang, A. Knebel, S. Grosjean, D. Wagner, S. Bräse, C. Wöll, J. Caro, L. Heinke (2016)
Tunable molecular separation by nanoporous membranes
Nature Communications, 7
Leslie Murray, M. Dincǎ, J. Yano, S. Chavan, S. Bordiga, C. Brown, J. Long (2010)
Highly-selective and reversible O2 binding in Cr3(1,3,5-benzenetricarboxylate)2.
Journal of the American Chemical Society, 132 23
Xiyi Li, Y. Pi, Qingqing Hou, Hao Yu, Zhong Li, Yingwei Li, Jing Xiao (2018)
Amorphous TiO2@NH2-MIL-125(Ti) homologous MOF-encapsulated heterostructures with enhanced photocatalytic activity.
Chemical communications, 54 15
Hui Wu, Y. Chua, V. Krungleviciute, M. Tyagi, Ping Chen, T. Yildirim, Wei Zhou (2013)
Unusual and highly tunable missing-linker defects in zirconium metal-organic framework UiO-66 and their important effects on gas adsorption.
Journal of the American Chemical Society, 135 28
N. Bobbitt, Matthew Mendonca, Ashlee Howarth, Timur Islamoglu, J. Hupp, O. Farha, O. Farha, R. Snurr (2017)
Metal-organic frameworks for the removal of toxic industrial chemicals and chemical warfare agents.
Chemical Society reviews, 46 11
Michael Katz, Su-Young Moon, Joseph Mondloch, M. Beyzavi, C. Stephenson, J. Hupp, J. Hupp, O. Farha, O. Farha (2015)
Exploiting parameter space in MOFs: a 20-fold enhancement of phosphate-ester hydrolysis with UiO-66-NH2 † †Electronic supplementary information (ESI) available. See DOI: 10.1039/c4sc03613a Click here for additional data file.
Chemical Science, 6
F. Vermoortele, B. Bueken, G. Bars, B. Voorde, M. Vandichel, Kristof Houthoofd, A. Vimont, M. Daturi, M. Waroquier, V. Speybroeck, C. Kirschhock, D. Vos (2013)
Synthesis modulation as a tool to increase the catalytic activity of metal-organic frameworks: the unique case of UiO-66(Zr).
Journal of the American Chemical Society, 135 31
Zhenlan Fang, Johannes Dürholt, Max Kauer, WenHua Zhang, C. Lochenie, Bettina Jee, Bauke Albada, N. Metzler‐Nolte, A. Pöppl, Birgit Weber, M. Muhler, Yuemin Wang, R. Schmid, R. Fischer (2014)
Structural complexity in metal-organic frameworks: simultaneous modification of open metal sites and hierarchical porosity by systematic doping with defective linkers.
Journal of the American Chemical Society, 136 27
Greig Shearer, S. Chavan, S. Bordiga, S. Svelle, U. Olsbye, K. Lillerud (2016)
Defect Engineering: Tuning the Porosity and Composition of the Metal–Organic Framework UiO-66 via Modulated Synthesis
Chemistry of Materials, 28
So-Hye Cho, Baoqing Ma, S. Nguyen, J. Hupp, T. Albrecht‐Schmitt (2006)
A metal-organic framework material that functions as an enantioselective catalyst for olefin epoxidation.
Chemical communications, 24
Carl Brozek, M. Dincǎ (2013)
Ti(3+)-, V(2+/3+)-, Cr(2+/3+)-, Mn(2+)-, and Fe(2+)-substituted MOF-5 and redox reactivity in Cr- and Fe-MOF-5.
Journal of the American Chemical Society, 135 34
M. Cliffe, W. Wan, X. Zou, P. Chater, A. Kleppe, M. Tucker, H. Wilhelm, N. Funnell, François-Xavier Coudert, A. Goodwin (2014)
Correlated Defect Nano-Regions in a Metal–Organic Framework
Nature communications, 5
O. Shekhah, Hui Wang, S. Kowarik, F. Schreiber, M. Paulus, M. Tolan, C. Sternemann, F. Evers, Denise Zacher, R. Fischer, C. Wöll (2007)
Step-by-step route for the synthesis of metal-organic frameworks.
Journal of the American Chemical Society, 129 49
C. Munuera, O. Shekhah, Hui Wang, C. Wöll, C. Ocal (2008)
The controlled growth of oriented metal-organic frameworks on functionalized surfaces as followed by scanning force microscopy.
Physical chemistry chemical physics : PCCP, 10 48
D. Dang, Pengyan Wu, Cheng He, Z. Xie, Chunying Duan (2010)
Homochiral metal-organic frameworks for heterogeneous asymmetric catalysis.
Journal of the American Chemical Society, 132 41
M Muller, S Turner, OI Lebedev, YM Wang, G Tendeloo, RA Fischer (2011)
Au@MOF-5 and Au/MOx@MOF-5 (M = Zn, Ti; X = 1, 2): preparation and microstructural characterisation
Eur J Inorg Chem, 2011
O. Shekhah, Raja Swaidan, Y. Belmabkhout, Marike Plessis, T. Jacobs, L. Barbour, I. Pinnau, M. Eddaoudi (2014)
The liquid phase epitaxy approach for the successful construction of ultra-thin and defect-free ZIF-8 membranes: pure and mixed gas transport study.
Chemical communications, 50 17
A. Corma, H. García, F. Xamena (2010)
Engineering metal organic frameworks for heterogeneous catalysis.
Chemical reviews, 110 8
Z. Gu, S. Grosjean, S. Bräse, C. Wöll, L. Heinke (2015)
Enantioselective adsorption in homochiral metal-organic frameworks: the pore size influence.
Chemical communications, 51 43
J. Evans, C. Sumby, C. Doonan (2014)
Post-synthetic metalation of metal-organic frameworks.
Chemical Society reviews, 43 16
Chao Gao, Jin Wang, Hangxun Xu, Y. Xiong (2017)
Coordination chemistry in the design of heterogeneous photocatalysts.
Chemical Society reviews, 46 10
D. Gallis, Marie Parkes, J. Greathouse, Xiaoyi Zhang, T. Nenoff (2015)
Enhanced O2 selectivity versus N2 by partial metal substitution in Cu-BTC
Chemistry of Materials, 27
Z. Gu, A. Pfriem, Sebastian Hamsch, H. Breitwieser, J. Wohlgemuth, L. Heinke, H. Gliemann, C. Wöll (2015)
Transparent films of metal-organic frameworks for optical applications
Microporous and Mesoporous Materials, 211
S. Kitagawa, S. Matsuyama, M. Munakata, T. Emori (1991)
Synthesis and crystal structures of novel one-dimensional polymers, [{M(bpen)X}∞][M = CuI, X = PF6–; M = AgI, X = ClO4–; bpen =trans-1,2-bis(2-pyridyl)ethylene] and [{Cu(bpen)(CO)(CH3CN)(PF6)}∞]
Journal of The Chemical Society-dalton Transactions

Publisher: Springer Journals
Copyright: Copyright © 2018 by The Author(s)
Subject: Chemistry; Catalysis; Industrial Chemistry/Chemical Engineering; Organometallic Chemistry; Physical Chemistry
ISSN: 1011-372X
eISSN: 1572-879X
DOI: 10.1007/s10562-018-2432-2
Publisher site: See Article on Publisher Site

Abstract

Keywords Metal–organic frameworks · Thin films · Single-site catalysts · Infrared spectroscopy · Defects · Active sites 1 Introduction Metal–organic frameworks (MOFs, also known as porous * Yuemin Wang coordination polymers or PCPs) are an emerging class of [email protected] porous materials of a hybrid organic/inorganic nature that * Christof Wöll combine the properties of both organic and inorganic porous [email protected] materials [1–7]. MOFs are typically stable up to tempera- Institute of Functional Interfaces, Karlsruhe Institute tures above 250 °C (in some cases, e.g., ZIF-8 [8], maximum of Technology, 76344 Eggenstein-Leopoldshafen, Germany Vol.:(0123456789) 1 3 2202 Y. Wang, C. Wöll temperatures as high as 550 °C can be tolerated). They vacancies, play a crucial role in the catalytic process [32]. exhibit a high degree of crystallinity and have large surface Recently, it has become evident that MOFs may feature a areas. The maximum degree of porosity and the size of the variety of intrinsic structural defects and the correspond- pores clearly exceed those of zeolites. In early 2017, the ing (intentional) defect engineering is a powerful strategy number of characterised MOFs was estimated to be 70,000 for advanced control of MOF chemical properties (Fig. 1) [9]. [33, 34]. The defect engineered MOFs (DEMOFs), synthe- Due to these unique chemical and physical properties sized by tailoring of linkers and/or metal ions, have shown MOF materials have opened up new perspectives in a variety modified physical and chemical properties [33– 48]. Both of different fields, ranging from gas storage and separation to local, isolated defects [modified CUS (mCUS)] and large- chemical sensing, catalysis, and drug delivery [10–21]. With scale defects (e.g. missing nodes, mesopores, Fig. 1) can be respect to applications in heterogeneous catalysis, different formed in DEMOFs and these defects can have important aspects must be considered. First, after adding additional consequences for their applications in catalysis. Further- coupling units (e.g., carboxylic acids or pyridine-units), more, MOF materials can serve as a host matrix (support) molecules active in homogeneous catalysis can be incorpo- for loading of catalytic components such as metal or metal rated into MOFs, thus providing a strategy to unite homo- oxide nanoparticles. These confined NPs inside MOFs may geneous and heterogeneous catalysis. Second, even without show unique properties which are significantly different further functionalization, many MOFs already show inter- from conventional supported catalysts. esting catalytic properties originating from the presence of In addition to MOF powders, the standard form of MOFs coordinatively unsaturated metal sites (CUS) at the nodes. obtained by the conventional solvothermal synthesis, a num- Such CUS sites are reactive for various chemical reactions. ber of methods have been developed to fabricate monolithic, A particular advantage of such sites in MOFs is that, com- crystalline, and highly oriented MOF thin films (SURMOFs) pared to oxide-supported metal nanoparticles (NPs), these [49–58]. Among them, the kinetically controlled layer-by- metal cations are highly dispersed within the framework of layer (lbl) or liquid phase epitaxy (LPE) growth process MOFs and thus serve as isolated, “single atom” catalytic has been extensively applied to produce well-defined SUR - sites. Accordingly, the interest in porous MOF materials as MOFs with a high degree of crystalline order, both vertical potential catalysts (in particular single-site catalysts [22]) and parallel to the substrate surface [59–64]. The highly- has intensified [22– 31]. ordered SURMOFs not only retain the intrinsic properties While in some MOFs CUS-sites are an intrinsic property of the corresponding MOFs, but also allow the design of of the MOF lattice itself, in other cases such undercoordi- architectures that cannot be achieved using MOF powders nated sites are absent in the ideal structure and only occur and to supplement their applicability as chemical sensors, as a result of defect formation within the framework mate- smart membranes, electronic and optoelectronic devices, rial. In the case of heterogeneous catalysis, e.g., on oxide as well as in catalytic coatings [65–68]. More importantly, surfaces, it is well known that defect sites, such as oxygen SURMOFs deposited on conducting substrates (e.g., Au) Fig. 1 Defect-engineered MOFs (DEMOFs). The modulation of the represent perfect and defect metal sites, respectively; the green high- defect structure on the micro and meso-scale by defect linker doping lighted unit indicates the parent micropores. Reproduced with per- of the framework is shown. The blue and short red sticks represent mission from Ref. [33]. Copyright 2014 American Chemical Society perfect and defective linkers, respectively; the yellow and black balls 1 3 Chemical Reactions at Isolated Single-Sites Inside Metal–Organic Frameworks 2203 can serve as model systems for a thorough study of MOF structure characterization of catalysts. However, a reliable properties by employing virtually all surface-sensitive tech- characterization of metal species in MOFs, and particularly niques developed in Surface Science because the charging those at defect sites in DEMOFs, is a challenge. Characteri- problems often hampering the analysis of bulk MOF sam- zation with electron microscopy, for example, is extremely ples are largely reduced. difficult since MOF materials contain organic ligands Overall, the extremely high structural and compositional which can be easily damaged by the high energy electrons design ability of MOF materials holds promise for their employed in TEM. Only very recently, Zhang et al. [83] have application in catalysis, including photocatalysis and electro- reported the high-quality atomic-resolution TEM images catalysis. The reactive properties of MOFs can vary signifi- of UiO-66 by developing a suite of methods to overcome cantly depending on the modification of both metal centers the experimental obstacles. Alternatively, MOFs can be and organic linkers as well as loading of metal/oxide NPs. characterized by spectroscopic techniques such as electron In this short report, we will highlight recent advances paramagnetic resonance, X-ray spectroscopy (XPS, EXAFS, in the field of MOF catalytic applications, with the main XANES) and infrared spectroscopy (FTIR). Furthermore, emphasis being on isolated, single active sites in perfect theoretical modeling of MOFs is required to properly inter- and defect-engineered MOFs, as well as for MOF thin films pret the experimental results. and SURMOFs. We will focus on structural and electronic properties as well as chemical reactivity of the selected MOF 2.1 Pristine MOFs systems based on fundamental investigations conducted primarily by our group and our collaboration partners. For The Cu-based HKUST-1 ([Cu btc ], btc = benzene-1,3,5- 3 2 other more general information about applications of MOFs tricarboxylate) is a prototypical MOF and has been used in catalysis and other fields we refer the reader to numerous in many studies [84]. This MOF contains so-called paddle- excellent review papers published recently (see e.g., [22, wheel units, where 4 carboxylate groups are bound to a 65–82]). Cu -dimer. In this interesting catalytic unit, the metal ions We will initially discuss the chemical reactions catalyzed are under-coordinated and can bind additional molecular by perfect and defect-engineered MOFs (e.g., Cu-HKUST-1, species (e.g., CO, H O, pyridine) at the axial position of the Ru-HKUST-1) using a combined experimental and theoreti- paddle-wheel units. Indeed, the CO oxidation reaction can cal approach. This section will be followed by a brief review be catalyzed by HKUST-1 at ambient pressure and elevated of the chemical nature and catalytic activity of SURMOF temperatures [85, 86]. In order to gain deeper insights into thin films. The next sections will focus on homochiral MOFs the active sites and reaction mechanisms, this system was as well as on metal and metal–oxide NPs embedded inside systematically investigated by using high-resolution ultra- MOFs. Finally, the enormous potential of SURMOF-based high vacuum infrared spectroscopy (UHV-FTIRS) in con- materials with respect to electrocatalysis will be highlighted. junction with density functional theory (DFT) calculations [87]. The sophisticated UHV-FTIRS apparatus combines a vacuum FTIR spectrometer (Bruker Vertex 80v) with a 2 Coordinatively Undercoordinated multi-chamber UHV system (Prevac), which not only ena- Single Active Sites in Pristine bles in situ transmission IR experiments on MOF powders and Defect‑Engineered MOFs (DEMOFs) supported on an inert metal mesh, but also allows the record- ing of IR reflection absorption spectroscopy (IRRAS) data To date, MOF materials have been extensively investigated, using a grazing incidence geometry on SURMOF thin films. and tremendous effort has been dedicated to their synthesis, This methodology has been demonstrated to be an invaluable properties and applications. However, a thorough atomic- tool to monitor chemical and photochemical reactions on the level understanding of structural and electronic properties surface of metal oxide powders [32]. 2+ −1 of the isolated, single active metal sites (CUS and mCUS) As shown in Fig. 2, the intrinsic Cu CUS (2179 cm ) as well as the structure–activity relationship continues to be was identified as the predominant species in HKUST-1, a major challenge; many crucial issues remain unanswered. while a small amount of native Cu defects were detected −1 This lack of information is due to the great complexity of as minor species (2125 cm , a few percent), in line with nanostructured MOFs, especially for DEMOFs in the pres- the observation for HKUST-1 thin films (see below in the ence of the different types of defects described below. A section of SURMOFs) [88]. Upon exposure to O , the UHV- comprehensive and fundamental understanding of active FTIRS data provide direct spectroscopic evidence for a sur- metal sites requires state-of-the-art analytical techniques prisingly high catalytic activity of Cu–MOFs (HKUST-1 that are suitable to probe the local chemical environments. and MOF-14, [Cu btb ], btb = 1,2,3-benzenetrisbenzoate). 3 2 Microscopic techniques [e.g., high-resolution transmis- Clearly, the presence of dioxygen leads to CO oxidation sion electron microscopy (HRTEM)] are powerful tools for even at temperatures as low as 105 K. The spectroscopic 1 3 2204 Y. Wang, C. Wöll Fig. 2 a UHV-FTIR spectra obtained after exposing [Cu btc ] cules adsorb on opposing paddle-wheel units in the iso configuration; 2 3 (HKUST-1) first to CO and subsequently to O at 105 K for differ -the O molecule is located (symmetrically) between these fragments 2 2 ent times (top). Intensity of the IR bands as a function of time for (top). Resulting structure: two C O molecules adsorb on different different CO species in the presence of molecular oxygen at 105 K paddle-wheel units (bottom). Reproduced with permission from Ref. (bottom). b Structure of HKUST-1. c Schematic representation of the [87]. Copyright 2012 John Wiley and Sons hypothetical reaction mechanism. Starting structure: two CO mole- information demonstrated that this reaction takes place only very interesting. Such modifications, of the general type 2+ on the intrinsic Cu CUS, whereas, rather unexpectedly, [M (btc) ], can be obtained by incorporating Mo [94], 3 2 the Cu defect sites are inactive for the low-temperature CO Cr [95], or Zn [96] into the parent MOF structure. These oxidation. On the basis of the high-level quantum chemical HKUST-1 analogues possess coordinatively unsaturated calculations, a concerted mechanism was proposed, whereby metal dimers at axial positions of paddle-wheel units where the impinging O molecule is activated in the presence of adsorption and chemical reactions may take place. More pre-adsorbed CO and interacts simultaneously with two iso- challenging is the synthesis of HKUST-1 analogues where carbonyl species at neighboring CUS to yield two C O mol- the central pair consists of metal ions in different charge ecules (see Fig. 2). Notably, this mechanism differs entirely states, thus yielding heterovalent paddle-wheel units. Such from those reported to occur in the case of CO oxidation mixed-valence MOFs are expected to show redox activities on metal oxides or on oxide-supported metal NPs (see e.g., [97, 98] and electric conducting properties [99, 100] that [89–93]). could be applicable to a porous electrode for batteries, fuel From a catalytic point of view, isostructural MOF vari- cells, capacitors, etc. ants of HKUST-1 where Cu is replaced by other metals are 1 3 Chemical Reactions at Isolated Single-Sites Inside Metal–Organic Frameworks 2205 In contrast to all other known [M (btc) ] frameworks that energies (see Fig. 3). These findings suggest that similar 3 2 II,II II,III are based on M units, the Ru–MOF, [Ru (btc) Cl ], complexity must be taken into explicit account for many 2 3 2 1.5 II,III exhibits mixed-valence R u paddle-wheel units with two other mixed valence MOFs with intrinsically low-coordi- 2+ 3+ differently charged metal centers (Ru and Ru ), which nated metal sites (CUS), which has not yet been accom- are stabilized by additional counter ions Cl (or in general plished in accurate detail. − − other X species such as OH ) to obtain an overall charge- neutral framework [101]. The combined results of UHV- 2.2 DEMOFs: Organic Linker Engineering FTIRS measurements using CO and CO as probe molecules and of accurate DFT calculations revealed that the structural The above discussion of MOF catalytic properties focuses and electronic properties of mixed-valence Ru–MOFs were mainly on reactant adsorption and reactive transformations much more complex than expected, and a straightforward occurring at CUS exposed at the metal ion nodes of the assignment of the observed IR bands was impossible. Two framework. However, the restricted specificity and the con- kinds of CO species bound to Ru cation sites were iden- fined coordination space of native CUS impose significant tified based on the isotopic substitution and temperature- limitations, and many MOF-types (e.g., layer-pillared MOFs 16 −1 dependent IR data (Fig. 3). The C O band at 2171 cm where Cu-paddlewheel-bound, 2D planes are stacked using, −1 18 (2120 cm for C O) was attributed to a weakly bonded e.g., bi-pyridine units) do not contain coordinatively unsatu- 16 −1 CO species, whereas the low-lying C O band at 2137 cm rated sites. In analogy to heterogeneous catalysts (e.g., metal −1 18 (2085 cm for C O) originated from a CO species with an oxides and supported metal NPs), where defects are known enhanced binding energy. A reasonable assignment, leading to be the active sites in catalysis [102], it is interesting to to the best-match between DFT calculations on both model also consider defects in MOFs. As shown in Fig. 2, reduced systems and experimental data, is based on the assumption Cu species were observed to occur as intrinsic defects (with that one of the Cl counter ions is transferred to a neighbor- a density of a few percent) in HKUST-1. ing paddle-wheel, forming an anionic secondary building Such defects should be absent in the perfect MOF lattice, unit blocked by two Cl counterions. As a consequence, the and, indeed, more sophisticated MOF fabrication methods II,III other positively charged paddle-wheel with a Ru dimer have been shown to reduce the concentrations of structural exposes two “free” CUS, where two different Ru–CO spe- imperfections [103], which can act as color centers [104]. cies could be formed with different frequencies and binding For “real” MOFs, however, the concentration of defects may Fig. 3 Temperature-dependent UHV-FTIR spectra obtained after and CO coordinated benzoate Ru-dimer paddle wheel systems as 16 18 exposing the clean Ru–MOF to a C O and b C O at 90 K and then models for local structures of Ru–MOF (atom coloring: ruthenium, 16 18 elevating the temperatures. a, b, (A) exposure to CO/ C O at 90 K; green; chlorine, magenta; carbon, black; oxygen, red; hydrogen, and heated to (B) 100 K, (C) 110 K, (D) 120 K, (E) 130 K, (F) 140 K, white). Reproduced with permission from Ref. [101]. Copyright 2013 (G) 150 K, (H) 160 K, (I) 170 K, (J) 180 K, and (K) 190 K. c Com- American Chemical Society puted model systems of CO adsorption for different scenarios of Cl 1 3 2206 Y. Wang, C. Wöll be sizeable, yielding different types of unsaturated sites numbers. Consequently, more CO molecules can adsorb to which strongly affect the chemical and physical properties of Cu mCUS with a higher binding energy with respect to 2+ 2+ these porous materials [105–112]. In this context, the inten- the parent Cu /Cu nodes, as confirmed by temperature- tional and controlled introduction of various defects into dependent IR analysis [33]. MOF frameworks is of great importance for rational design In addition to the local coordinatively undercoordinated of MOF materials with desired specific properties [33– 48]. metal sites created by integrating fragmented linkers with A particularly elegant way to introduce defects into MOFs one coupling unit missing (type A: mCUS, see Fig. 5), lattice is by use of “defective” linkers [33, 38, 45]. By adjusting defects corresponding to the complete absence of metal ions the concentration of these modified linkers relative to the (type B: node vacancies) could be formed by raising the dop- regular ones the defect concentration can be precisely tuned. ing concentration of defect linkers in DEMOFs. The coex- Such DEMOFs are of a more complex nature compared to istence of defects of both types A and B in Cu–DEMOFs the (more or less) “defect-free” reference materials due to was demonstrated by the combined UHV-FTIRS and XPS the structural heterogeneity resulting from the incorpora- approach [113]. The node vacancies are directly related to tion of the defect linkers or metal ions. A comprehensive the formation of functionalized mesopores, or large-scale experimental characterization in conjunction with theory is defects, in DEMOFs (Fig. 1) [33]. Hupp and coworkers required for a fundamental understanding of the defects in have reported that the introduction of node vacancies (type DEMOFs. In the case of HKUST-1 ([Cu btc ]; Cu-BTC), B defects) into HKUST-1 can finely tune the sorption prop- 3 2 Marx et al. demonstrated defect engineering of CUS via the erties of MOFs [114]. These results revealed the structural solvothermal synthesis with carefully chosen fragmented modulations in DEMOFs at two different length scales in a linkers [38]. In the resulting framework, the trivalent single step, which overcame restrictions of active site speci- 3− btc linker was partially replaced by divalent pyridine- ficity and the confined coordination spaces at the isolated, 2− 3,5-dicarboxylate (pydc ). Such linker substitution was single metal centers. expected to yield reduced Cu CUS at the defect-modified The multivariate nature of DEMOFs represents a new paddlewheel unit. However, the expected change of the oxi- dimension of tailoring functions. In catalysis, both pristine dation state for the copper species was not detected based on and mixed-linker Cu–MOFs showed high catalytic activity the XANES and EXAFS results in Ref. [38]. It is worth not- toward low-temperature hydroxylation of aromatic com- ing that the pristine HKUST-1, in the form of both powders pounds, while the product selectivity was significantly modi- 2− [33, 87] and thin films (SURMOFs) [88], features intrinsi- fied in the presence of pydc linkers [38]. We have further cally reduced Cu sites as the minority species, the amount investigated CO oxidation and alcohol oxidation reactions of which depends on the synthesis, oxidative or reductive within defect-engineered HKUST-1 by IR spectroscopy. treatment, and the activation conditions. Whereas the reduced Cu species are inactive for the low- Fischer and coauthors reported a series of defect-engi- temperature CO oxidation, methanol oxidation occurs at + 2+ neered HKUST-1 via systematic and controlled framework mixed-valence Cu /Cu metal nodes (mCUS), indicating incorporation of various types of defect linkers Lx (L1-L4, special catalytic properties of DEMOFs due to the coexist- see Fig. 4a) using the mixed-linker solid-solution approach ence of low-coordinated Cu CUS (i.e., more electron-rich 2− as a novel synthesis strategy [33]. To gain more detailed sites) and the adjacent defect linkers (pydc ) as functional- insights into the local environments of the mCUS, UHV- ized groups [33]. FTIR spectroscopy was employed to monitor the chemisorp- The same kind of defect engineering has been reported for tion and thermal desorption of CO on different DEMOFs the mixed-valence [Ru btc ] structural analogue of HKUST- 3 2 (Fig. 4). A large number of Cu-related CO bands were 1, where defects were introduced in a controlled manner by a observed which varied in shape and intensity depending on mixed-component (native btc and defect linkers) solid-solu- the nature and density of the defect linkers L1–L4. These tion approach to yield Ru–DEMOFs [36, 37]. The high-level findings revealed the existence of copper species with vari- spectroscopic characterization using primarily UHV-FTIRS ous chemical and structural environments. The assignment and X-ray based techniques (XPS, XANES, XRD) demon- of the CO vibrations was assisted by quantum mechanical/ strated the successful incorporation of various defect linkers molecular mechanical (QM/MM) calculations. The com- that, however, did not reduce the overall integrity and robust- bined results from UHV-FTIRS, XPS, and theory provided ness of the framework in a substantial way [36, 37]. Depend- solid evidence for the simultaneous and controllable modi- ing on the nature and concentration of fragmented linkers, fication of the electronic properties and the proximate coor - both defects of type A and type B (Fig. 5) were detected. δ+ dination space at the metal centers (mCUS) upon incorpo- The type A defects feature reduced R u (0 < δ < 2) sites at ration of defect linkers (see Fig. 4c) [33]. The doping of the modified metal nodes resulting from the fragmented or HKUST-1 with Lx led to the formation of reduced Cu / missing linkers. The formation of node vacancies (defects 2+ Cu paddlewheel units (nodes) with lowered coordination B) was facilitated by the doping with 5-X-isophthalic acids 1 3 Chemical Reactions at Isolated Single-Sites Inside Metal–Organic Frameworks 2207 + 2+ Fig. 4 A Defect Linker concept for DEMOFs: illustration of increas- mixed valence defect Cu /Cu (btc) (pydc) being typical for sample 2− 3− 2− ing defect degree by Lx incorporation, i.e. btc /Lx exchange. DEMOFs (L4) is shown and energetically feasible binding modes for The defect linkers L1–L3 were chosen as benzene-1,3-dicarboxylates one to three coordinated (adsorbed) CO molecules are given (only 2− with various functional groups at 5-position (L1: nidc , –NO ; L2: the QM system is shown for clarity, Cu, brown; C, black; O, red; N, 2− 2− cydc ; –CN; L3: h ydc , –OH) and L4 was pyridine-3,5-dicarbox- blue; H, white) together with computed (scaled) CO stretching nor- 2− −1 ylate (pydc ). B UHV-FTIR spectra obtained after exposing repre- mal mode frequencies (cm ). (e) For comparison the defect is shown sentative DEMOF samples ([Cu (btc) (Lx) ]) with different defect in a close-up, indicating the embedding of the QM system in the MM 3 2−d d linkers L1–L4 to various amounts of CO at 90 K. C QM/MM com- environment. Reproduced with permission from Ref. [33]. Copyright puted binding modes of CO. (a–d) The QM/MM model for a local 2014 American Chemical Society 1 3 2208 Y. Wang, C. Wöll work [36, 37] revealed that the Ru–DEMOFs, synthesized by controlled incorporation of different kinds of defect link - ers, exhibited unusual reactivity for the CO conversion to CO in a dark environment. This reaction does not occur at the “defect-free” Ru-HKUST-1, as supported by the UHV- FTIRS data (Fig. 6) which showed only C O -related IR −1 12 −1 13 bands at 2335 cm ( CO ) and 2272 cm ( CO ). How- 2 2 2− ever, the introduction of pydc defect linkers led to the −1 appearance of low-frequency bands at 2040 and 2000 cm δ+ assigned to CO bound to modified Ru CUS, which were accompanied by a gradual decrease of CO signals. These findings led to the conclusion that the low-temperature (90 K) conversion of C O to CO is driven by strong interac- δ+ tions with reduced R u CUS (i.e., more electron-rich sites) in Ru–DEMOFs. As a result, the enhanced charge transfer from Ru3d to the C O 2π antibonding orbital can facilitate 2 u δ− the formation of chemisorbed C O species that may act as an intermediate to finally give rise to CO. The reactivity Fig. 5 Scheme of different defect types in the [M (BTC) ] (HKUST- of Ru–DEMOFs toward the C O conversion depended not 3 2 1, M = Cu, Ru) family as well as the regular paddlewheel units. The δ+ only on the concentration of reduced Ru , but also on the purple sphere in defect type B stands for a vacancy of the missing nature of defect linkers. The pydc linkers further promoted metal node. Reproduced with permission from Ref. [113]. Copyright the activation of CO due to the presence of basic pyridyl 2017 John Wiley and Sons δ+ N sites in proximity to the reactive Ru mCUS (possible formation of pyridyl N O species [121]), while the 5-OH- (5-X-ip, X = OH, H, NH , Br) linkers where the functional ip-doped Ru–DEMOFs showed much lower reactivity as groups X are much smaller than carboxylate or non-coordi- compared to pydc-doped materials [37]. nating groups (e.g., H). The presence of type B defects in Furthermore, the pydc-modified Ru–DEMOFs, pre- Ru–DEMOFs led to enhanced porosity yielding mesopores, treated with hydrogen at 423 K, exhibited dramatically as was observed for Cu–DEMOFs (see Fig. 1) [33]. enhanced activity and selectivity for olefin hydrogenation MOF-based materials have shown great competency for versus the competing isomerization side reaction [36]. the photocatalytic or electrocatalytic reduction of CO to This outcome was attributed to the efficient formation of CO and other value-added chemicals [115–120]. Our recent Ru–H species via a heterolytic, base-assisted activation δ+ Fig. 6 a UHV-FTIR spectra (the regions of C O and CO vibrations) ing reduced and lower-coordinated Ru reactive centers and func- obtained after exposing the parent and defect-engineered Ru–MOFs tionalized defect linkers. Reproduced with permission from Ref. [36]. to CO at 90 K. b Structure of the defect-engineered Ru–MOFs show- Copyright 2014 John Wiley and Sons 1 3 Chemical Reactions at Isolated Single-Sites Inside Metal–Organic Frameworks 2209 of dihydrogen at the cooperative active centers including potential to be similarly modified in a controlled manner δ+ 2− reduced Ru mCUS and with the adjacent p ydc serving by the choice of the functionalized defect linkers. as a suitable base ligand. The Ru–H species were iden- tified by the characteristic vibrations at 1956–1975 and 2.3 Mixed‑Metal DEMOFs: Metal Node Engineering −1 2057–2076 cm [36]. The proposed reaction mechanism is described in Fig. 7, where the formation of Ru–H is Along with the linker modification in DEMOFs as discussed most likely the rate-determining step [36]. above, the chemical nature of MOF materials can also be The simultaneous presence of two types of defects A precisely tuned by partial metal substitution at framework and B markedly affected the catalytic activities of 5-X- nodes. The latter approach has been employed to synthe- ip (X = OH, H, NH , Br) engineered Ru–DEMOFs [37]. size mixed-metal DEMOFs with the partial substitution of δ+ 2+ 2+ The reduced Ru sites (type A) were responsible for the intrinsic Cu centers in HKUST-1 by Zn and other met- enhanced catalytic performance for ethylene dimerization als of 3d-row (Mn, Fe, Co) that have similar effective ionic 2+ due to the redox properties of Ru mCUS, as observed for radii and are thus closely related with Cu in coordination RhCa-X Zeolite catalysts [122]. Regarding the Paar–Knorr chemistry [123, 124]. The corresponding DEMOFs showed pyrrole synthesis, the Ru–DEMOFs showed much higher enhanced selective sorption of O resulting from the incor- catalytic activity for the conversion of phenylamine to poration of second metal ions into the framework [123]. The pyrrole, as compared to the parent Ru–MOF. Again, this doping with metals of the Pd group is of special interest transformation was attributed to the presence of type A due to their novel catalytic activity for numerous reactions. δ+ defects, where the reduced Ru mCUS (single active However, the introduction of metals of the 4d or 5d row is sites) are bound to the O atom of the carbonyl group and more challenging because the presence of these metal ions facilitate nucleophilic attack by the ion-pair of the amino makes 3D crystal formation difficult due to kinetic reasons group of the phenylamine [37]. Interestingly, an increase [125, 126]. in the density of incorporated 5-OH-ip led to a decrease Recently, the mixed metal Pd@[Cu Pdx(btc) ] with 3−x 2 n of the yield of pyrrole [37]. This result could be explained various levels of doping with Pd were obtained via one-pot in terms of the gradual dominance of defects B at higher synthesis [127]. The XPS results provided evidence for the 2+ doping levels; the formation of node vacancies eliminated simultaneous introduction of Pd -doped framework nodes δ+ 0 part of the reactive Ru centers, thus accounting for the and Pd NPs embedded into MOFs. As shown in Fig. 8, reduced catalytic activity of Ru–DEMOFs. three Pd 3d doublets (3d and 3d ) were resolved in the 5/2 3/2 Overall, our results demonstrated the controlled incor- deconvoluted Pd3d core-level spectra. The two doublets poration of various defect linkers into isoreticular Cu- and at 338.9/344.2 eV (Pd1) and 337.9/343.2 eV (Pd2) were 2+ Ru–MOFs (HKUST-1). The structural, electronic, and ascribed to Pd species, revealing the successful incorpo- 2+ reactive properties of Cu–DEMOFs and Ru–DEMOFs ration of Pd into the framework of Cu-HKUST-1 leading varied strongly depending on the density and nature of to the formation of Cu–Pd and/or Pd–Pd paddlewheels. The the fragmented linkers. Other [M (btc) ] compounds have doublet at 335.8/341.0 eV (Pd3) is characteristic for metallic 3 2 Fig. 7 Olefin hydrogena- tion involving base-assisted heterolytic splitting of H over defect-engineered Ru–MOFs. Note that the pydc linker in DEMOFs offers a basic pyridyl- N atom in the proximity of the reactive Ru centers. Reproduced with permission from Ref. [36]. Copyright 2014 John Wiley and Sons 1 3 2210 Y. Wang, C. Wöll Fig. 8 a Deconvoluted XPS data of Pd@[Cu Pd (btc) ] 3−x x 2 n MOFs with various doping levels of Pd in HKUST-1. b Simultaneous incorporation 2+ 2+ 0 of Pd /M nodes and Pd NPs dispersion into MOF. The 2+ Pd sites in such designed MOFs play an important role in enhancing the catalytic activity of the hydrogenation of p-nitrophenol with NaBH to p-aminophenol. Reproduced with permission from Ref. [127]. Copyright 2016 Royal Society of Chemistry Pd species; its relative concentration increased as the dop- predominantly responsible for the observed high catalytic ing level of Pd increased, indicating the simultaneous load- activity [127]. ing of Pd NPs into the framework. Along with the DEMOFs in HKUST-1 topology, intrin- 2+ 0 Both Pd -containing MOFs [128–130] and Pd @MOFs sic and intentionally created atomic-level defects in other [131–134] exhibited superior catalytic performance for typi- types of MOFs (e.g., Zr–MOFs (UiO-66, UiO-67) [45, 47, cal palladium-catalyzed reactions such as the Suzuki C–C 135–138], NU-125 [139], MOF-69 [35], MIL-53 [35]) have coupling and hydrogenation. The Pd@[Cu Pd (btc) ] been the subject of numerous experimental investigations. 3−x x 2 n 2+ MOFs featuring both incorporated Pd nodes and loaded The defects of type A (reduced metal centers with more open Pd NPs show substantially enhanced catalytic activity coordination environments) were generated either by a direct toward the aqueous-phase hydrogenation of p-nitrophenol synthesis strategy or by post-synthesis approaches. In addi- with NaBH to p-aminophenol, as contrasted with the pris- tion, Brozek and Dinca reported the fabrication of a series of tine Cu–MOFs (HKUST-1). Furthermore, it was evident mixed-metal MOF-5 analogues via isomorphous substitution 2+ 2+ that the Pd species play a key role in this reaction and are at the Zn O cornerstone (see Fig. 9), where the Zn species 1 3 Chemical Reactions at Isolated Single-Sites Inside Metal–Organic Frameworks 2211 varied depending on the quality of MOF thin films that could be controlled in a straightforward fashion [142]. As discussed above for MOF powders, the defect-engineered SURMOFs can be fabricated by controlled introduction of defects using different strategies such as fragmented linker incorporation [33, 38], or thermal treatment [39, 143]. It is expected that the intentional creation of defects inside SURMOFs has important consequences for tuning the electronic structure and catalytic properties of MOF materials. 2+ Fig. 9 Isomorphous substitution of Zn by other metal cations at the The lbl method can also be used to fabricate MOF mem- Zn O cornerstone of MOF-5. Reproduced with permission from Ref. branes. The ability to separate different molecules allows [140]. Copyright 2013 American Chemical Society the integration of size-exclusion principles to MOF-based catalysts. The first SURMOF-based monolithic membrane 2+ was fabricated by Shekhah et al. [144] and was reported to were partially replaced by metal cations with the same (Cr , 2+ 2+ 3+ 3+ 3+ Mn, Fe ) or different oxidation states (Ti, V, Cr be well-suited for the separation of small molecules, e.g., H, N CO, CO, CH , as well as other small hydrocarbons. with Cl as counter-ion) [140]. Furthermore, the approach 2 2, 2 4 of partial post-synthetic metal exchange was employed to A more recent study has demonstrated the use of MOF- based membranes for the natural gas purification and high- produce mixed Al/Fe-MIL-53, Zr/Ti-UiO-66 as well as Zr/ Hf-UiO-66 MOFs featuring mixed metal nodes in the frame- value industrial separations such as butane isomers [145]. Furthermore, it has been shown that the unique opportuni- work [141]. Overall, these different types of defects have been shown to account for the high reactivity of MOF cata- ties to functionalize MOFs permits numerous interesting, membrane-related functionalities, including membranes lysts for a number of catalytic reactions [40]. The controlled incorporation of MOFs with defects of different types and where the permeability and selectivity can be switched on by light [146, 147]. As shown in Fig. 11, the photoswitch- concentrations represents a novel approach for the predic- tive rational design of MOF-based single-site catalysts at able SURMOF membrane was fabricated by assembling linkers decorated with photoresponsive azobenzene-side- the atomic level. groups into the framework, where the precise control of the cis/trans azobenzene ratio by controlled irradiation times 3 MOF Thin Films Grown with ultraviolet or visible light allows for a continuous tun- ing of the separation of molecular mixtures [146]. Since this by the Layer‑by‑Layer Method approach can also be applied to fabricate large-area (larger than 20 cm × 20 cm) membranes [148], and also by apply- Employing the lbl or LPE method, established by Wöll and coworkers [59], to fabricate crystalline, monolithic MOF ing spray-methods, it is, in principle, suited for a continuous coating process. thin films, or SURMOFs [65] affords interesting oppor - tunities for MOF applications in catalysis. In addition to With respect to catalysis, a particularly interesting aspect of SURMOFs is the possibility to combine two different providing well-defined SURMOF substrates which can be applied for chemical transformations as observed for MOF types of chemically active MOFs into one multilayer thin film or membrane by using heteroepitaxy. This approach bulk powders, the lbl method can be used to introduce differ - ent types of defects in SURMOFs, e.g. at internal interfaces allows the creation of tandem catalysts where two different catalytically active components can be incorporated into one in hetero-multilayer structures [65]. In addition, interstitial sites can be created by loading guest species, including single, monolithic thin film (or membrane). The close proximity of two different catalytically active metal or oxide NPs or nanoclusters (NCs), inside the parent SURMOF materials. species which can be realized by a programmed lbl approach is important in the context of reaction cascades with short- An instructive example are HKUST-1 SURMOFs grown on an MHDA/Au substrates (see Fig. 10). The experimen- lived intermediates. In addition, a number of different cata- lysts may interfere, e.g., one catalyst affects the action of tal data from UHV-FTIRS and XPS were interpreted using electronic structure calculation and allowed to derive a the other, or leads to decomposition of the second catalyst. Avoiding these unwanted effects can be achieved by anchor - rather consistent picture [88]. The results showed consist- ently the presence of a small amount (~ 4%) of reduced ing the active species within a three-dimensional porous network. As opposed to just mixing the two catalysts in a Cu species in the pristine HKUST-1 thin film. Upon heat- ing, the temperature-induced creation of Cu defects was liquid, embedding the two different catalysts in a MOF will maintain their individual activities. clearly observed (Fig. 10). The density of intrinsic defects 1 3 2212 Y. Wang, C. Wöll Fig. 10 a Schematic drawing of HKUST-1 grown on an MHDA/ Au substrate. b XP spectra of HKUST-1 SURMOF at dif- ferent temperatures. c UHV- IRRAS spectra of CO adsorbed on activated HKUST-1 SURMOF at 110 K. The sample was annealed at 350 and 420 K. Reproduced with permission from Ref. [88]. Copyright 2012 John Wiley and Sons One of the first demonstrations of such tandem catalysts catalyzed by the Mn-porphyrin to yield epoxide as the realized by the lbl approach are porphyrin-based SUR- reactive intermediate. In a second step, the proximally MOFs. In the paper by Hupp and coworkers [149], a two- sited Zn-porphyrin facilitates the insertion of C O into component SURMOF was grown on a correspondingly the epoxide, giving rise to the cyclic carbonate as the final functionalized substrate (see Fig. 12). This hybrid system product (Fig. 12d). comprising two different metallo-porphyrins (ZnMn-RPM) The technological impact of such tandem catalysts can was shown to be active toward the epoxidation of olefin be improved substantially by realizing them in the form of substrates (Mn-porphyrin) and for epoxide opening (Zn- thin membranes through which the reactants are passed. porphyrin). Although this system could not yet be realized This technology will combine size-exclusion properties in the form of a membrane, this tandem SURMOF thin with catalytic activities. A particular advantage of the layer yielded catalytic turnover numbers which were sub- molecular framework-based approach for catalyst design stantially higher than the corresponding bulk MOF materi- is that the influence of the introduction of additional side- als [149]. The reaction studies in this case was a tandem groups to the MOF–ligands on the chemical activities can reaction consisting of first methoxy-styrene epoxidation be explored in a relatively straightforward fashion. In most 1 3 Chemical Reactions at Isolated Single-Sites Inside Metal–Organic Frameworks 2213 Fig. 11 a Schematic illustra- tion of tunable, remote-con- trollable molecular selectivity by a photoswitchable MOF membrane. b SEM cross- section image of the SURMOF membrane on the mesoporous a-Al O . c The structure of 2 3 Cu (AzoBPDC) (AzoBiPyB) 2 2 with the azobenzene groups. The transition between trans and cis states can be tuned by irradiation with 365 and 455 nm light, respectively. Reproduced with permission from Ref. [146]. Copyright 2016 Springer Nature cases, adding additional functionalities (e.g. OH, –NH , We would like to conclude this section on MOF thin films –CH , etc.) to a ligand will not change the overall structure by pointing out that SURMOFs are also well-suited to study of the MOF. transport phenomena occurring in these framework materi- This approach has been used to improve the efficiency als in a systematic fashion. One example are so-called sur- of a UiO-66 based catalyst for phosphate ester hydrolysis, face barriers, which are relevant for most porous materials. where a rate enhancement of up to 20 times was observed for By using a quartz-crystal microbalance (QCM) based setup, UiO-66 after modification by amino (NH ) moieties that act Heinke et al. could demonstrate that in case of HKUST-I, as a proton-transfer agent during the catalysis cycle [150]. these surface-barriers are not an intrinsic property of MOFs The particular advantage of MOFs in this context is the but result from surface imperfections originating from water- ability to integrate functional units into a porous framework induced corrosion [152]. material without changing the overall architecture of the MOF, which allows tuning of the chemical activity without affecting diffusivities, etc.. Additionally, the catalytic perfor - 4 Homochiral MOFs and Enantioselective mance of MOF materials could also be tuned via the incor- Asymmetric Catalysis poration of inorganic groups containing metal centers as side-groups [22]. This procedure was termed post-synthetic Kim and coworkers reported the first homochiral MOF metalation (PSMet) as the additional catalytically-active (POST-1) that catalyzes a transesterification reaction in an metal moieties can only be added post-synthetically [151]. enantioselective manner [153]. Since this seminal work, The same decoration strategies of MOF–ligands also apply homochiral MOFs have been extensively investigated with to MOF thin films, which enable the multifunctional proper - the aim to rationally fabricate and engineer MOFs mate- ties of SURMOFs to be adjusted in a controlled manner (see rials for heterogeneous asymmetric catalysis. These kinds e.g. the photoswitchable SURMOF membrane depicted in of MOFs can be obtained via distinct strategies such as Fig. 11 [146]). introduction of achiral active centers during synthesis, 1 3 2214 Y. Wang, C. Wöll Fig. 12 a The porphyrinic dipyridine pillar used in the construction of the ZnMn- RMP MOF containing a Mn atom, which can be used as an epoxidation catalyst, and b the porphyrinic tetracarboxylic acid strut used to make the 2D sheets of the ZnMn-RPM MOF containing a Zn atom, which can act as an epoxide-opening catalyst. c Crystallographically- derived representation of a unit cell of the ZnMn-RPM framework. d Schematic repre- sentation of tandem catalysis of ZnMn-RPM for the synthesis of cyclic carbonate. Reproduced with permission from Ref. [149]. Copyright 2016 John Wiley and Sons post-synthetic modification of homochiral MOFs, or incor - in Fig. 13, nanosized homochiral titanium oxo-clusters poration of asymmetric catalysts directly into the framework (Ti–MOCs) were embedded into HKUST-1 frameworks by [154–160]. The substantial potential of homochiral MOFs in using the LPE lbl method [170]. The resulting Ti–MOC@ enantioselective asymmetric catalytic reactions has been dis- HKUST-1 metacrystal was quite efficient regarding enan - cussed by a number of different groups [25, 155, 161–166]. tiomer recognition and separation. Although the combina- Tremendous efforts have been dedicated to homochiral tion of enantiomer-selectivity with catalytically activities MOF powder materials. However, investigations of the cor- in MOF thin films has not been explored, we consider the responding MOF membranes and thin films (SURMOFs) potential of this direction to be enormous, in particular, are few. Only recently, Wöll, Fischer and coworkers reported when combined with membranes. the fabrication of a series of enantiopure metal-camphorate frameworks (MCamFs) deposited on a quartz crystal micro- balance (QCM) substrate via an in situ LPE lbl approach by 5 Metal and Oxide Nanoparticles Embedded changing the metal nodes and/or linker molecules in succes- within MOFs sive deposition cycles [167–170]. Enantioselectivity with regard to the diffusion of different enantiomers into a MOF In the previous paragraphs, we have demonstrated the great thin film can be modulated by using linkers of different chi- potential of MOFs for catalytic performance and it is far rality [167, 168]. In addition, a thorough study of isoreticu- from being fully exploited. But even more possibilities exist lar chiral SURMOFs with identical stereogenic centers but to add further dimensions to the application of MOFs in different pore dimensions demonstrated that the pore sizes catalysis. A particularly important one is the impregnation must be adjusted to achieve the highest enantioselectivity of MOFs with NCs or NPs. Under mild conditions (tem- in chiral nanoporous materials [169]. Furthermore, chiral perature below 250–550 °C, depending on type of MOF), metal–organic nanoclusters (MOCs) can be loaded into the the porous molecular frameworks are sufficiently stable to achiral MOFs, again, achieving a high selectivity between prevent sintering or agglomeration of embedded, catalyti- the diffusivity of different enantiomers [170]. As shown cally active particles, the most severe problems encountered 1 3 Chemical Reactions at Isolated Single-Sites Inside Metal–Organic Frameworks 2215 inside MOFs accounted for the high catalytic activity for liq- uid-phase aerobic oxidation of alcohols (see Fig. 14d). The nano-sized bimetallic alloys are known to show enhanced catalytic performance in numerous reactions as compared to their monometallic counterparts. However, the exclusive encapsulation of bimetallic NPs with tunable com- positions into MOFs is challenging [174–179]. More recently, the embedding of core–shell PdPt and RuPt nano-alloys into Zr-based MOFs (UiO-66 and its derivatives) was realized by template synthesis [180]. The resulting bimetallic core–shell NPs exhibited substrate specic fi size-selectivity and signifi - cantly enhanced catalytic activity for the hydrogenation of nitrobenzene compared to pure Pt loaded UiO-66 [181]. The catalytic performance of MOF materials can also be tuned in a controllable way by encapsulation of vari- ous metal oxide NPs [182–185]. The surface structure and reactivity of nanostructured ZnO particles, embedded into ZIF-8 via chemical vapor infiltration followed by oxidative annealing, were characterized by UHV-FTIRS using C O as a probe molecule [185]. In contrast to pure ZnO NPs exposing mainly non-polar (10–10) surfaces, the confined ZnO NPs inside ZIF-8 were dominated by polar O–ZnO and Zn–ZnO facets as well as defect sites, which were highly reactive for CO activation. The isolated metal oxides (e.g., ZnO, T iO, Fe O ) stabilized within the MOF matrix 2 2 3 showed enhanced multifunctional (catalytic, magnetic, opti- cal) properties and have promising applications in catalysis, photocatalysis, and other fields such as electronic devices and sensors [182–185]. In comparison to MOF bulk powders, much less informa- tion is available for the loading of MOF thin films (SUR - Fig. 13 a Structure of the R–Ti–MOC clusters. b Schematic presenta- MOFs) with metal or metal oxide NPs. Recently, Wöll and tion of in situ lbl growth of enantiopure Ti–MOC-loaded HKUST-1 coworkers reported the first fabrication of Bi O NPs encap- 2 3 thin film using LPE approach. Reproduced with permission from Ref. sulated into HKUST-1 thin films via a novel approach, in [170]. Copyright 2016 American Chemical Society which bismuth-triphenyl was used to create small bismuth oxide particles into the MOF pores [186]. Also in this case the size of the largest Bi O clusters slightly exceeded that when exploiting the high chemical activity of such small 2 3 particles for chemical transformations. of the MOF pores. The size distribution could be narrowed down substantially and at the same time shifted to lower Several strategies exist with regard to loading metal, metal oxide or other chemically active NPs into the MOFs. One of values by adding amino groups acting as nucleation centers to the MOF linkers. Without changing the MOF architecture, the first papers in this area used metal containing precursors to realize small Pd-clusters embedded in the MOF [171]. In this lattice constant, and topology, these additional amino groups acted as nucleation centers, thus achieving a much narrower case, the liberation of the metal atoms was achieved by either exposure to high pressures of H or by irradiation with light. size distribution. Such bismuth oxide particles are highly active in photocatalysis, as demonstrated by the photodegra- It is noteworthy that the palladium clusters were substantially larger than the pores of the MOFs (Fig. 14 case b) [171]. In a dation of nuclear fast red (NFR, C H NO SNa) dye [186]. 14 8 7 similar manner, Au NPs were loaded into different MOF mate- rials (e.g., ZIFs [172], MOF-5 [173]) and distributed homo- 6 SURMOFs and Electrocatalysis geneously over the MOF matrix matching with the cavities (Fig. 14 case c) as conr fi med by HRTEM observations. The Thin MOF films deposited on an electrode also exhibit size distribution and shape of embedded NPs was controlled by the framework structure and the functional groups at the interesting properties in electrochemistry and electroca- talysis [187, 188]. In particular, monolithic, pinhole-free linkers. The homogeneous distribution of confined Au NPs 1 3 2216 Y. Wang, C. Wöll Fig. 14 Top: three characteristic cases of microstructures for NPs narrow size distribution matching with the cavities and homogene- supported by MOFs. a Particles typically larger than the cavity size ously distributed over the volume of MOF. Bottom: d schematic view with a preferred anchoring close to the outer surface of the MOF. b of liquid phase alcohol oxidation with the Au@ZIF-8 material; Both Particles evenly distributed throughout the volume of the MOF crys- benzyl alcohol (BA) and methyl benzoate (MB) are able to access the tal but still exhibiting a broad size distribution with an average par- pores and can diffuse through the network. Reproduced with permis- ticle size exceeding the dimensions of the pores. c Particles with a sion from Ref. [172]. Copyright 2010 American Chemical Society SURMOFs, MOF thin films prepared using the lbl-process In addition to the demonstration of the suitability of SUR- (see Sect. 3, above) exhibited a great potential with respect MOFs for electrochemistry (see above), exciting properties to electrochemistry [189–191]. Although the application of toward photovoltaics (construction of MOF thin film based SURMOFs, both empty and after loading with electroactive solar cells [193, 194]) have been demonstrated. compounds such as ferrocene, has been quite successful, applications in electrocatalysis have been less common. In a recent paper by Liu, Wöll, Sun, and coworkers [192], 7 Summary and Outlook a monolithic, pinhole-free Re-based SURMOF was grown on a conductive, transparent substrate (fluorinated tin oxide, The selected examples of MOF chemical activity discussed or FTO) and exhibited well-defined electrochemical proper - in this short review clearly demonstrate the great potential ties. As demonstrated by the X-ray diffraction (XRD) data, of these porous framework materials for catalysis. Active the MOF films were highly oriented, with the [001] direc- sites can be introduced into these crystalline coordination tion perpendicular to the substrate. These SURMOFs were networks using a broad variety of strategies, and MOFs can shown to be highly effective in the electrocatalytic conver - be used for catalysis either as powders or in the form of sion of CO to CO. The faradaic efficiency found in these thin films (SURMOFs), with the possibility to also fabricate experiments was astonishingly high, amounting to 93 ± 5%. catalytically active membranes. The combined experimental Furthermore, the current densities which could be achieved and theoretical results presented above for selected systems for these high-quality monolithic coatings were found to provided deep, fundamental insights into the structural, elec- −2 be larger than 2 mA cm , thus exceeding the densities tronic and reactive properties of active sites in pristine and recorded for MOF thin films prepared using other methods defect-engineered MOFs (DEMOFs). Depending on the sys- by at least one order of magnitude. tem, isolated, coordinatively unsaturated metal sites (CUS) Although few applications have so far been reported are either an intrinsic component of the perfect system or for photo-electrocatalysis of MOF thin films (e.g., MOFs can be introduced by e.g. defect engineering or by loading as photosensitizers on T iO nanowires for water splitting with suitable guest species, thus creating the potential to fab- [193]), we also foresee enormous potential in this direction. ricate single-site catalysts [22]. The catalytic performance of 1 3 Chemical Reactions at Isolated Single-Sites Inside Metal–Organic Frameworks 2217 CuI[4,4′,4″,4‴-tetracyanotetraphenylmethane]BF .xC H NO . MOFs can be significantly enhanced by tailoring of organic 4 6 5 2 J Am Chem Soc 112:1546–1554 linkers and/or metal cations via defect-engineering strategies 2. Kitagawa S, Matsuyama S, Munakata M, Emori T (1991) in a controlled manner. The resulting DEMOFs are of highly Synthesis and crystal structures of novel one-dimensional I – I complex nature due to the presence of different types of polymers, [{M(bpen)X} ][M = Cu , X = PF ; M = A g , X = ∞ 6 ClO ; bpen = trans-1,2-bis(2-pyridyl)ethylene] and [{Cu(bpen) defects including mCUS (type A: reduced metal centers with (CO)(CH CN)(PF )} ]. J Chem Soc-Dalton Trans. https ://doi. 3 6 ∞ more open coordination space) and node vacancies (type B: org/10.1039/DT991 00028 69. missing metal centers). The defects of type A, together with 3. Gardner GB, Venkataraman D, Moore JS, Lee S (1995) Spon- the proximate functionalized defect linker, were proven to taneous assembly of a hinged coordination network. Nature 374:792–795 play a key role in the catalytic activity of DEMOFs. The 4. Yaghi OM, Li HL (1995) Hydrothermal synthesis of a metal- chemical and physical properties of MOF materials can be organic framework containing large rectangular channels. J Am further precisely modified by adding organic or metal-con- Chem Soc 117:10401–10402 taining functional groups or by embedding of metal, alloy 5. Riou D, Ferey G (1998) Hybrid open frameworks (Mil-N). Part 3 - crystal structures of the Ht and Lt forms of MIL-7: a new or metal oxide NPs into frameworks. vanadium propylenediphosphonate with an open-framework. MOF-based materials, especially MOF thin films coated influence of the synthesis temperature on the oxidation state on various supports, hold also great promise for the appli- of vanadium within the same structural type. J Mater Chem cation in electrocatalysis as well as in photocatalysis and 8:2733–2735 6. O’Keeffe M, Eddaoudi M, Li HL, Reineke T, Yaghi OM (2000) can be utilized in various environment and energy-related Frameworks for extended solids: geometrical design principles. reactions such as water splitting and CO reduction. J Solid State Chem 152:3–20 Although the unique catalytic activities of MOF and 7. Kitagawa S, Kitaura R, Noro S (2004) Functional porous coor- SURMOF materials for various chemical reactions, a thor- dination polymers. Angew Chem-Int Ed 43:2334–2375 8. Park KS, Ni Z, Cote AP, Choi JY, Huang RD, Uribe-Romo FJ, ough atomic-level understanding of the active centers inside Chae HK, O’Keeffe M, Yaghi OM (2006) Exceptional chemical MOFs has not yet been achieved. Many important issues and thermal stability of zeolitic imidazolate frameworks. Proc (e.g., the structure–activity relationships) remain to be a Natl Acad Sci USA 103:10186–10191 substantial challenge. This lack of information results from 9. Moghadam PZ, Li A, Wiggin SB, Tao A, Maloney AGP, Wood PA, Ward SC, Fairen-Jimenez D (2017) Development of a the structural complexity in pristine and defect-engineered cambridge structural database subset: a collection of metal- MOFs and SURMOFs. Overall, it is mandatory to perform organic frameworks for past, present, and future. Chem Mater comprehensive fundamental studies by combining high- 29:2618–2625 level microscopic (e.g. HRTEM [83]) and spectroscopic 10. Kreno LE, Leong K, Farha OK, Allendorf M, Van Duyne RP, Hupp JT (2012) Metal-organic framework materials as chemical (e.g. vibrational spectroscopy and X-ray based techniques) sensors. Chem Rev 112:1105–1125 characterizations in conjunction with theory. In this context, 11. Li JR, Sculley J, Zhou HC (2012) Metal-organic frameworks for MOF thin films are excellent model systems which allow separations. Chem Rev 112:869–932 the application of standard methods developed in Surface 12. Murray LJ, Dinca M, Long JR (2009) Hydrogen storage in metal- organic frameworks. Chem Soc Rev 38:1294–1314 Science. 13. Corma A, Garcia H, Xamena F (2010) Engineering metal organic frameworks for heterogeneous catalysis. Chem Rev Acknowledgements We acknowledge financial support from the Ger - 110:4606–4655 man Research Foundation (DFG), as well as from the “Science and 14. Ferey G (2008) Hybrid porous solids: past, present, future. Chem Technology of Nanosystems” Programme (Project No. 432202). Soc Rev 37:191–214 15. Cohen SM (2012) Postsynthetic methods for the functionalization Open Access This article is distributed under the terms of the Crea- of metal-organic frameworks. Chem Rev 112:970–1000 tive Commons Attribution 4.0 International License (http://creat iveco 16. Long JR, Yaghi OM (2009) The pervasive chemistry of metal- mmons.or g/licenses/b y/4.0/), which permits unrestricted use, distribu- organic frameworks. Chem Soc Rev 38:1213–1214 tion, and reproduction in any medium, provided you give appropriate 17. Chen BL, Liang CD, Yang J, Contreras DS, Clancy YL, Lobko- credit to the original author(s) and the source, provide a link to the vsky EB, Yaghi OM, Dai S (2006) A microporous metal-organic Creative Commons license, and indicate if changes were made. framework for gas-chromatographic separation of alkanes. Angew Chem-Int Ed 45:1390–1393 18. Bloch ED, Queen WL, Krishna R, Zadrozny JM, Brown CM, Long JR (2012) Hydrocarbon separations in a metal-organic framework with open iron(II) coordination sites. Science References 335:1606–1610 19. Talin AA, Centrone A, Ford AC, Foster ME, Stavila V, Haney P, 1. Hoskins BF, Robson R (1990) Design and Construc - Kinney RA, Szalai V, El Gabaly F, Yoon HP, Leonard F, Allen- tion of a new class of scaffolding-like materials compris- dorf MD (2014) Tunable electrical conductivity in metal-organic ing infinite polymeric frameworks of 3-D-linked molec- framework thin-film devices. Science 343:66–69 ular rods—a reappraisal of the Zn(Cn) and Cd(Cn) 20. Furukawa S, Reboul J, Diring S, Sumida K, Kitagawa S (2014) 2 2 structures and the synthesis and structure of the dia- Structuring of metal-organic frameworks at the mesoscopic/mac- I II mond-related frameworks [N(CH ) ][Cu Zn (CN) ] and roscopic scale. Chem Soc Rev 43:5700–5734 3 4 4 1 3 2218 Y. Wang, C. Wöll 21. Schneemann A, Bloch ED, Henke S, Llewellyn PL, Long JR, 39. Vermoortele F, Bueken B, Le Bars G, Van de Voorde B, Van- Fischer RA (2015) Influence of solvent-like sidechains on the dichel M, Houthoofd K, Vimont A, Daturi M, Waroquier M, adsorption of light hydrocarbons in metal-organic frameworks. Van Speybroeck V, Kirschhock C, De Vos DE (2013) Synthe- Chem-Eur J 21:18764–18769 sis modulation as a tool to increase the catalytic activity of 22. Rogge SMJ, Bavykina A, Hajek J, Garcia H, Olivos-Suarez AI, metal-organic frameworks: the unique case of UiO-66(Zr). J Sepulveda-Escribano A, Vimont A, Clet G, Bazin P, Kapteijn F, Am Chem Soc 135:11465–11468 Daturi M, Ramos-Fernandez EV, Xamena F, Van Speybroeck V, 40. Canivet J, Vandichel M, Farrusseng D (2016) Origin of highly Gascon J (2017) Metal-organic and covalent organic frameworks active metal-organic framework catalysts: defects? defects! as single-site catalysts. Chem Soc Rev 46:3134–3184 Dalton Trans 45:4090–4099 23. Lee J, Farha OK, Roberts J, Scheidt KA, Nguyen ST, Hupp JT 41. Liu YY, Klet RC, Hupp JT, Farha O (2016) Probing the cor- (2009) Metal-organic framework materials as catalysts. Chem relations between the defects in metal-organic frameworks and Soc Rev 38:1450–1459 their catalytic activity by an epoxide ring-opening reaction. 24. Farrusseng D, Aguado S, Pinel C (2009) Metal-organic Chem Commun 52:7806–7809 frameworks: opportunities for catalysis. Angew Chem-Int Ed 42. Slater B, Wang ZR, Jiang SX, Hill MR, Ladewig BP (2017) 48:7502–7513 Missing linker defects in a homochiral metal-organic frame- 25. Yoon M, Srirambalaji R, Kim K (2012) Homochiral metal- work: tuning the chiral separation capacity. J Am Chem Soc organic frameworks for asymmetric heterogeneous catalysis. 139:18322–18327 Chem Rev 112:1196–1231 43. Yuan SA, Zou LF, Qin JS, Li JL, Huang L, Feng LA, Wang XA, 26. Valvekens P, Vermoortele F, De Vos D (2013) Metal-organic Bosch M, Alsalme A, Cagin T, Zhou HC (2017) Construction of frameworks as catalysts: the role of metal active sites. Catal hierarchically porous metal-organic frameworks through linker Sci Technol 3:1435–1445 labilization. Nat Commun 8:10 27. Dhakshinamoorthy A, Garcia H (2014) Metal-organic frame- 44. Park J, Wang ZYU, Sun LB, Chen YP, Zhou HC (2012) Intro- works as solid catalysts for the synthesis of nitrogen-containing duction of functionalized mesopores to metal-organic frame- heterocycles. Chem Soc Rev 43:5750–5765 works via metal-ligand-fragment coassembly. J Am Chem Soc 28. Liu JW, Chen LF, Cui H, Zhang JY, Zhang L, Su CY (2014) 134:20110–20116 Applications of metal-organic frameworks in heterogeneous 45. Wu H, Chua YS, Krungleviciute V, Tyagi M, Chen P, Yildi- supramolecular catalysis. Chem Soc Rev 43:6011–6061 rim T, Zhou W (2013) Unusual and highly tunable missing- 29. Gao C, Wang J, Xu HX, Xiong YJ (2017) Coordination chem- linker defects in zirconium metal-organic framework UiO-66 istry in the design of heterogeneous photocatalysts. Chem Soc and their important effects on gas adsorption. J Am Chem Soc Rev 46:2799–2823 135:10525–10532 30. Huang YB, Liang J, Wang XS, Cao R (2017) Multifunctional 46. Cliffe MJ, Wan W, Zou XD, Chater PA, Kleppe AK, Tucker metal-organic framework catalysts: synergistic catalysis and MG, Wilhelm H, Funnell NP, Coudert FX, Goodwin AL (2014) tandem reactions. Chem Soc Rev 46:126–157 Correlated defect nanoregions in a metal-organic framework. Nat 31. Zhu L, Liu XQ, Jiang HL, Sun LB (2017) Metal-organic Commun 5:8 frameworks for heterogeneous basic catalysis. Chem Rev 47. Gutov OV, Hevia MG, Escudero-Adan EC, Shafir A (2015) 117:8129–8176 Metal-organic framework (MOF) defects under control: insights 32. Wang YM, Wöll C (2017) IR Spectroscopic investigations of into the missing linker sites and their implication in the reactivity chemical and photochemical reactions on metal oxides: bridg- of zirconium-based frameworks. Inorg Chem 54:8396–8400 ing the materials gap. Chem Soc Rev 46:1875–1932 48. Trickett CA, Gagnon KJ, Lee S, Gandara F, Burgi HB, Yaghi OM 33. Fang ZL, Durholt JP, Kauer M, Zhang WH, Lochenie C, Jee (2015) Definitive molecular level characterization of defects in B, Albada B, Metzler-Nolte N, Poppl A, Weber B, Muhler M, UiO-66 crystals. Angew Chem-Int Ed 54:11162–11167 Wang YM, Schmid R, Fischer RA (2014) Structural complex- 49. Kanaizuka K, Haruki R, Sakata O, Yoshimoto M, Akita Y, Kita- ity in metal-organic frameworks: simultaneous modification of gawa H (2008) Construction of highly oriented crystalline sur- open metal sites and hierarchical porosity by systematic doping face coordination polymers composed of copper dithiooxamide with defective linkers. J Am Chem Soc 136:9627–9636 complexes. J Am Chem Soc 130:15778–15779 34. Fang ZL, Bueken B, De Vos DE, Fischer RA (2015) Defect- 50. Zacher D, Shekhah O, Wöll C, Fischer RA (2009) Thin films of engineered metal-organic frameworks. Angew Chem-Int Ed metal-organic frameworks. Chem Soc Rev 38:1418–1429 54:7234–7254 51. Shekhah O, Liu J, Fischer RA, Wöll C (2011) MOF thin films: 35. Ravon U, Savonnet M, Aguado S, Domine ME, Janneau E, existing and future applications. Chem Soc Rev 40:1081–1106 Farrusseng D (2010) Engineering of coordination polymers 52. Betard A, Fischer RA (2012) Metal-organic framework thin films: for shape selective alkylation of large aromatics and the role from fundamentals to applications. Chem Rev 112:1055–1083 of defects. Microporous Mesoporous Mater 129:319–329 53. Bradshaw D, Garai A, Huo J (2012) Metal-organic framework 36. Kozachuk O, Luz I, Xamena F, Noei H, Kauer M, Albada HB, growth at functional interfaces: thin films and composites for Bloch ED, Marler B, Wang YM, Muhler M, Fischer RA (2014) diverse applications. Chem Soc Rev 41:2344–2381 Multifunctional, defect-engineered metal-organic frameworks 54. Otsubo K, Kitagawa H (2014) Metal-organic framework thin with ruthenium centers: sorption and catalytic properties. films with well-controlled growth directions confirmed by X-ray Angew Chem-Int Ed 53:7058–7062 study. APL Mater 2:11 37. Zhang WH, Kauer M, Halbherr O, Epp K, Guo PH, Gonzalez 55. Li WJ, Tu M, Cao R, Fischer RA (2016) Metal-organic frame- MI, Xiao DJ, Wiktor C, Xamena F, Wöll C, Wang YM, Muhler work thin films: electrochemical fabrication techniques and M, Fischer RA (2016) Ruthenium metal-organic frameworks corresponding applications & perspectives. J Mater Chem A with different defect types: influence on porosity, sorption, and 4:12356–12369 catalytic properties. Chem-Eur J 22:14297–14307 56. Zhuang JL, Terfort A, Wöll C (2016) Formation of oriented and 38. Marx S, Kleist W, Baiker A (2011) Synthesis, structural prop- patterned films of metal-organic frameworks by liquid phase epi- erties, and catalytic behavior of Cu-BTC and mixed-linker taxy: a review. Coord Chem Rev 307:391–424 57. Edler KJ, Yang B (2013) Formation of mesostructured thin films Cu-BTC-Pydc in the oxidation of benzene derivatives. J Catal at the air-liquid interface. Chem Soc Rev 42:3765–3776 281:76–87 1 3 Chemical Reactions at Isolated Single-Sites Inside Metal–Organic Frameworks 2219 58. Qiu SL, Xue M, Zhu GS (2014) Metal-organic framework mem- 77. Adil K, Belmabkhout Y, Pillai RS, Cadiau A, Bhatt PM, Assen branes: from synthesis to separation application. Chem Soc Rev AH, Maurin G, Eddaoudi M (2017) Gas/vapour separation using 43:6116–6140 ultra-microporous metal-organic frameworks: insights into the 59. Shekhah O, Wang H, Kowarik S, Schreiber F, Paulus M, Tolan structure/separation relationship. Chem Soc Rev 46:3402–3430 M, Sternemann C, Evers F, Zacher D, Fischer RA, Wöll C (2007) 78. Rubio-Martinez M, Avci-Camur C, Thornton AW, Imaz I, Step-by-step route for the synthesis of metal-organic frameworks. Maspoch D, Hill MR (2017) New synthetic routes towards MOF J Am Chem Soc 129:15118–15119 production at scale. Chem Soc Rev 46:3453–3480 60. Munuera C, Shekhah O, Wang H, Wöll C, Ocal C (2008) The 79. Cao XH, Tan CL, Sindoro M, Zhang H (2017) Hybrid micro-/ controlled growth of oriented metal-organic frameworks on func- nano-structures derived from metal-organic frameworks: prepa- tionalized surfaces as followed by scanning force microscopy. ration and applications in energy storage and conversion. Chem Phys Chem Chem Phys 10:7257–7261 Soc Rev 46:2660–2677 61. Shekhah O, Wang H, Zacher D, Fischer RA, Wöll C (2009) 80. Easun TL, Moreau F, Yan Y, Yang SH, Schroder M (2017) Struc- Growth mechanism of metal-organic frameworks: insights into tural and dynamic studies of substrate binding in porous metal- the nucleation by employing a step-by-step route. Angew Chem- organic frameworks. Chem Soc Rev 46:239–274 Int Ed 48:5038–5041 81. Yu JM, Xie LH, Li JR, Ma YG, Seminario JM, Balbuena PB 62. Shekhah O, Wang H, Paradinas M, Ocal C, Schupbach B, Terfort (2017) CO capture and separations using MOFs: computational A, Zacher D, Fischer RA, Wöll C (2009) Controlling interpen- and experimental studies. Chem Rev 117:9674–9754 etration in metal-organic frameworks by liquid-phase epitaxy. 82. Schoedel A, Li M, Li D, O’Keeffe M, Yaghi OM (2016) Struc- Nat Mater 8:481–484 tures of metal-organic frameworks with rod secondary building 63. Darbandi M, Arslan HK, Shekhah O, Bashir A, Birkner A, units. Chem Rev 116:12466–12535 Wöll C (2010) Fabrication of free-standing ultrathin films of 83. Zhang DL, Zhu YH, Liu LM, Ying XR, Hsiung CE, Sougrat porous metal-organic frameworks by liquid-phase epitaxy and R, Li K, Han Y (2018) Atomic-resolution transmission electron subsequent delamination. Phys Status Solidi-Rapid Res Lett microscopy of electron beam-sensitive crystalline materials. Sci- 4:197–199 ence 359:675 64. Fischer RA, Wöll C (2009) Layer-by-layer liquid-phase epitaxy 84. Chui SSY, Lo SMF, Charmant JPH, Orpen AG, Williams ID of crystalline coordination polymers at surfaces. Angew Chem- (1999) A chemically functionalizable nanoporous material Int Ed 48:6205–6208 [Cu (TMA) (H O) ] . Science 283:1148–1150. 3 2 2 3 n 65. Liu JX, Wöll C (2017) Surface-supported metal-organic frame- 85. Ye JY, Liu CJ (2011) Cu-3(Btc)(2): CO oxidation over MOF work thin films: fabrication methods, applications, and chal- based catalysts. Chem Commun 47:2167–2169 lenges. Chem Soc Rev 46:5730–5770 86. Zhao YG, Padmanabhan M, Gong QH, Tsumori N, Xu Q, Li 66. Falcaro P, Ricco R, Doherty CM, Liang K, Hill AJ, Styles MJ J (2011) CO catalytic oxidation by a metal organic framework (2014) MOF positioning technology and device fabrication. containing high density of reactive copper sites. Chem Commun Chem Soc Rev 43:5513–5560 47:6377–6379 67. Stavila V, Talin AA, Allendorf MD (2014) MOF-based electronic 87. Noei H, Amirjalayer S, Muller M, Zhang XN, Schmid R, Muhler and optoelectronic devices. Chem Soc Rev 43:5994–6010 M, Fischer RA, Wang YM (2012) Low-temperature CO oxida- 68. Stassen I, Burtch N, Talin A, Falcaro P, Allendorf M, Ameloot R tion over Cu-based metal-organic frameworks monitored by (2017) An updated roadmap for the integration of metal-organic using FTIR spectroscopy. ChemCatChem 4:755–759 frameworks with electronic devices and chemical sensors. Chem 88. St Petkov P, Vayssilov GN, Liu JX, Shekhah O, Wang YM, Wöll Soc Rev 46:3185–3241 C, Heine T (2012) Defects in MOFs: a thorough characterization. 69. Yang QH, Xu Q, Jiang HL (2017) Metal-organic frameworks ChemPhysChem 13:2025–2029 meet metal nanoparticles: synergistic effect for enhanced cataly - 89. Haruta M, Kobayashi T, Sano H, Yamada N (1987) Novel gold sis. Chem Soc Rev 46:4774–4808 catalysts for the oxidation of carbon-monoxide at a temperature 70. Kitao T, Zhang YY, Kitagawa S, Wang B, Uemura T (2017) far below 0-degrees-C. Chem Lett 16:405–408 Hybridization of MOFs and polymers. Chem Soc Rev 90. Haruta A (2003) When gold is not noble: catalysis by nanopar- 46:3108–3133 ticles. Chem Rec 3:75–87 71. Chen LY, Luque R, Li YW (2017) Controllable design of tunable 91. Schubert MM, Hackenberg S, van Veen AC, Muhler M, Plzak nanostructures inside metal-organic frameworks. Chem Soc Rev V, Behm RJ (2001) CO oxidation over supported gold catalysts- 46:4614–4630 "inert” and “active” support materials and their role for the oxy- 72. Medishetty R, Zareba JK, Mayer D, Samoc M, Fischer RA (2017) gen supply during reaction. J Catal 197:113–122 Nonlinear optical properties, upconversion and lasing in metal- 92. Freund HJ, Meijer G, Schee ffl r M, Schlogl R, Wolf M (2011) CO organic frameworks. Chem Soc Rev 46:4976–5004 oxidation as a prototypical reaction for heterogeneous processes. 73. Li X, Liu YX, Wang J, Gascon J, Li JS, Van der Bruggen B Angew Chem-Int Ed 50:10064–10094 (2017) Metal-organic frameworks based membranes for liquid 93. Over H, Muhler M (2003) Catalytic Co oxidation over ruthe- separation. Chem Soc Rev 46:7124–7144 nium—bridging the pressure gap. Prog Surf Sci 72:3–17 74. Lustig WP, Mukherjee S, Rudd ND, Desai AV, Li J, Ghosh SK 94. Kramer M, Ulrich SB, Kaskel S (2006) Synthesis and proper- (2017) Metal-organic frameworks: functional luminescent and ties of the metal-organic framework Mo (BTC) (TUDMOF-1). 3 2 photonic materials for sensing applications. Chem Soc Rev J Mater Chem 16:2245–2248. 46:3242–3285 95. Murray LJ, Dinca M, Yano J, Chavan S, Bordiga S, Brown 75. Bobbitt NS, Mendonca ML, Howarth AJ, Islamoglu T, Hupp CM, Long JR (2010) Highly-selective and reversible O bind- JT, Farha OK, Snurr RQ (2017) Metal-organic frameworks for ing in Cr (1,3,5-benzenetricarboxylate) . J Am Chem Soc 3 2 the removal of toxic industrial chemicals and chemical warfare 132:7856–7857. agents. Chem Soc Rev 46:3357–3385 96. Feldblyum JI, Liu M, Gidley DW, Matzger AJ (2011) Recon- 76. Lian XZ, Fang Y, Joseph E, Wang Q, Li JL, Banerjee S, Lol- ciling the discrepancies between crystallographic porosity and lar C, Wang X, Zhou HC (2017) Enzyme-MOF (metal-organic guest access as exemplified by Zn-HKUST-1. J Am Chem Soc framework) composites. Chem Soc Rev 46:3386–3401 133:18257–18263 1 3 2220 Y. Wang, C. Wöll 97. Ferey G, Millange F, Morcrette M, Serre C, Doublet ML, Grene- metal-organic frameworks and its effects on gas uptake proper - che JM, Tarascon JM (2007) Mixed-valence Li/Fe-based metal- ties. Inorg Chem 53:6914–6919 organic frameworks with both reversible redox and sorption 115. S. Diercks C, Liu Y, Cordova K, M. Yaghi O (2018) The role of properties. Angew Chem-Int Ed 46:3259–3263 reticular chemistry in the design of CO reduction catalysts. Nat 98. Combelles C, Ben Yahia M, Pedesseau L, Doublet ML (2011) Mater 17:301–307. Fe-II/Fe-III mixed-valence state induced by Li-insertion into the 116. Wang C, Xie ZG, deKrafft KE, Lin WL (2011) Doping metal-organic-framework MIL53(Fe): a DFT + U study. J Power metal-organic frameworks for water oxidation, carbon diox- Sources 196:3426–3432 ide reduction, and organic photocatalysis. J Am Chem Soc 99. Takaishi S, Hosoda M, Kajiwara T, Miyasaka H, Yamashita M, 133:13445–13454 Nakanishi Y, Kitagawa Y, Yamaguchi K, Kobayashi A, Kita- 117. Ryu UJ, Kim SJ, Lim HK, Kim H, Choi KM, Kang JK (2017) gawa H (2009) Electroconductive porous coordination polymer Synergistic interaction of Re complex and amine functionalized Cu[Cu(pdt) ] composed of donor and acceptor building units. multiple ligands in metal-organic frameworks for conversion of Inorg Chem 48:9048–9050. carbon dioxide. Sci Rep 7:8 100. Kobayashi Y, Jacobs B, Allendorf MD, Long JR (2010) Conduc- 118. Choi KM, Kim D, Rungtaweevoranit B, Trickett CA, Barmanbek tivity, doping, and redox chemistry of a microporous dithiolene- JTD, Alshammari AS, Yang PD, Yaghi OM (2017) Plasmon- based metal-organic framework. Chem Mater 22:4120–4122 enhanced photocatalytic CO conversion within metal organic 101. Noei H, Kozachuk O, Amirjalayer S, Bureekaew S, Kauer M, frameworks under visible light. J Am Chem Soc 139:356–362. Schmid R, Marler B, Muhler M, Fischer RA, Wang YM (2013) 119. Kornienko N, Zhao YB, Kiley CS, Zhu CH, Kim D, Lin S, Chang CO adsorption on a mixed-valence ruthenium metal-organic CJ, Yaghi OM, Yang PD (2015) Metal-organic frameworks for framework studied by UHV-FTIR spectroscopy and DFT calcu- electrocatalytic reduction of carbon dioxide. J Am Chem Soc lations. J Phys Chem C 117:5658–5666 137:14129–14135 102. Xu MC, Noei H, Fink K, Muhler M, Wang YM, Wöll C (2012) 120. Hod I, Sampson MD, Deria P, Kubiak CP, Farha OK, Hupp JT The surface science approach for understanding reactions on (2015) Fe-porphyrin-based metal-organic framework films as oxide powders: the importance of IR spectroscopy. Angew high-surface concentration, heterogeneous catalysts for electro- Chem-Int Ed 51:4731–4734 chemical reduction of CO . ACS Catal 5:6302–6309. 103. Gu ZG, Pfriem A, Hamsch S, Breitwieser H, Wohlgemuth J, 121. Jain SL, Sain B (2002) Ruthenium catalyzed oxidation of tertiary Heinke L, Gliemann H, Wöll C (2015) Transparent films of nitrogen compounds with molecular oxygen: an easy access to metal-organic frameworks for optical applications. Microporous N-oxides under mild conditions. Chem Commun 10:1040–1041 Mesoporous Mater 211:82–87 122. Bass JS, Kevan L (1990) Electron-spin-resonance and elec- 104. Muller K, Fink K, Schottner L, Koenig M, Heinke L, Wöll C tron-spin echo spectroscopic studies of paramagnetic rhodium (2017) Defects as color centers: the apparent color of metal- species produced in RhCa-X zeolite during ethylene dimeriza- 2+ organic frameworks containing Cu -based paddle-wheel units. tion - evidence for a sigma-bonded intermediate. J Phys Chem ACS Appl Mater Interfaces 9:37463–37467. 94:1483–1489 105. Shoaee M, Agger JR, Anderson MW, Attfield MP (2008) Crys- 123. Sava Gallis DF, Parkes MV, Greathouse JA, Zhang XY, Nenoff tal form, defects and growth of the metal organic framework TM (2015) Enhanced O selectivity versus N by partial metal 2 2 Hkust-1 revealed by atomic force microscopy. CrystEngComm substitution in Cu-BTC. Chem Mater 27:2018–2025. 10:646–648 124. Gul-E-Noor F, Jee B, Mendt M, Himsl D, Poppl A, Hartmann 106. Cairns AB, Goodwin AL (2013) Structural disorder in molecular M, Haase J, Krautscheid H, Bertmer M (2012) Formation of framework materials. Chem Soc Rev 42:4881–4893 mixed metal Cu Zn (Btc)(2) frameworks with different zinc 3–X x 2+ 107. Chizallet C, Lazare S, Bazer-Bachi D, Bonnier F, Lecocq V, contents: incorporation of Zn into the metal-organic frame- Soyer E, Quoineaud AA, Bats N (2010) Catalysis of transes- work structure as studied by solid-state NMR. J Phys Chem C terification by a nonfunctionalized metal-organic framework: 116:20866–20873. acido-basicity at the external surface of ZIF-8 probed by FTIR 125. Nickerl G, Stoeck U, Burkhardt U, Senkovska I, Kaskel S and Ab initio calculations. J Am Chem Soc 132:12365–12377 (2014) A catalytically active porous coordination polymer 108. Xamena F, Cirujano FG, Corma A (2012) An Unexpected bifunc- based on a dinuclear rhodium paddle-wheel unit. J Mater Chem tional acid base catalysis in Irmof-3 for Knoevenagel condensa- A 2:144–148 tion reactions. Microporous Mesoporous Mater 157:112–117 126. Teo JM, Coghlan CJ, Evans JD, Tsivion E, Head-Gordon M, 109. Bunck DN, Dichtel WR (2013) Mixed linker strategies for Sumby CJ, Doonan CJ (2016) Hetero-bimetallic metal-organic organic framework functionalization. Chem-Eur J 19:818–827 polyhedra. Chem Commun 52:276–279 110. Park TH, Hickman AJ, Koh K, Martin S, Wong-Foy AG, San- 127. Zhang WH, Chen ZH, Al-Naji M, Guo PH, Cwik S, Halbherr O, ford MS, Matzger AJ (2011) Highly dispersed palladium(II) in a Wang YM, Muhler M, Wilde N, Glaser R, Fischer RA (2016) defective metal-organic framework: application to C–H activa- Simultaneous introduction of various palladium active sites into tion and functionalization. J Am Chem Soc 133:20138–20141 MOF via one-pot synthesis: Pd@Cu Pd (BTC)(2)(N). Dalton 3–X x 111. Diring S, Furukawa S, Takashima Y, Tsuruoka T, Kitagawa S Trans 45:14883–14887. (2010) Controlled multiscale synthesis of porous coordination 128. Xamena F, Abad A, Corma A, Garcia H (2007) MOFs as cata- polymer in nano/micro regimes. Chem Mater 22:4531–4538 lysts: activity, reusability and shape-selectivity of a Pd-contain- 112. Al-Janabi N, Fan XL, Siperstein FR (2016) Assessment of ing MOF. J Catal 250:294–298 2+ 0 MOF’s Quality: quantifying defect content in crystalline porous 129. Schuster S, Klemm E, Bauer M (2012) The Role of Pd /Pd in materials. J Phys Chem Lett 7:1490–1494 hydrogenation by Pd(2-Pymo)(2)(N): an X-ray absorption and 113. Zhang WH, Kauer M, Guo PH, Kunze S, Cwik S, Muhler M, IR spectroscopic study. Chem-Eur J 18:15831–15837 Wang YM, Epp K, Kieslich G, Fischer RA (2017) Impact of 130. Opelt S, Krug V, Sonntag J, Hunger M, Klemm E (2012) synthesis parameters on the formation of defects in HKUST-1. Investigations on stability and reusability of Pd(2-Pymo)(2) Eur J Inorg Chem 2017:925–931 (N) as hydrogenation catalyst. Microporous Mesoporous Mater 114. Barin G, Krungleviciute V, Gutov O, Hupp JT, Yildirim T, 147:327–333 Farha OK (2014) Defect creation by linker fragmentation in 1 3 Chemical Reactions at Isolated Single-Sites Inside Metal–Organic Frameworks 2221 131. Sabo M, Henschel A, Froede H, Klemm E, Kaskel S (2007) Solu- metal-organic frameworks with visible light. Chem-Eur J tion infiltration of palladium into MOF-5: synthesis, physisorp- 23:5434–5438 tion and catalytic properties. J Mater Chem 17:3827–3832 148. Hurrle S, Friebe S, Wohlgemuth J, Wöll C, Caro J, Heinke L 132. Gole B, Sanyal U, Banerjee R, Mukherjee PS (2016) High load- (2017) Sprayable, large-area metal-organic framework films and ing of Pd nanoparticles by interior functionalization of MOFs for membranes of varying thickness. Chem-Eur J 23:2294–2298 heterogeneous catalysis. Inorg Chem 55:2345–2354 149. Beyzavi MH, Vermeulen NA, Zhang KN, So M, Kung CW, 133. Wang C, Zhang HY, Feng C, Gao ST, Shang NZ, Wang Z (2015) Hupp JT, Farha OK (2016) Liquid-phase epitaxially grown Multifunctional Pd@MOF core-shell nanocomposite as highly metal-organic framework thin films for efficient tandem cataly - active catalyst for p-nitrophenol reduction. Catal Commun sis through site-isolation of catalytic centers. ChemPlusChem 72:29–32 81:708–713 134. Yuan BZ, Pan YY, Li YW, Yin BL, Jiang HF (2010) A highly 150. Katz MJ, Moon SY, Mondloch JE, Beyzavi MH, Stephenson CJ, active heterogeneous palladium catalyst for the Suzuki- Hupp JT, Farha OK (2015) Exploiting parameter space in MOFs: Miyaura and Ullmann coupling reactions of aryl chlorides in A 20-fold enhancement of phosphate-ester hydrolysis with UiO- aqueous media. Angew Chem-Int Ed 49:4054–4058 66-NH . Chem Sci 6:2286–2291 135. Oien S, Wragg D, Reinsch H, Svelle S, Bordiga S, Lamberti 151. Evans JD, Sumby CJ, Doonan CJ (2014) Post-synthetic metala- C, Lillerud KP (2014) Detailed structure analysis of atomic tion of metal-organic frameworks. Chem Soc Rev 43:5933–5951 positions and defects in zirconium metal-organic frameworks. 152. Heinke L, Gu ZG, Wöll C (2014) The surface barrier phenom- Cryst Growth Des 14:5370–5372 enon at the loading of metal-organic frameworks. Nat Commun 136. Shearer GC, Chavan S, Ethiraj J, Vitillo JG, Svelle S, Olsbye 5:4562 U, Lamberti C, Bordiga S, Lillerud KP (2014) Tuned to per- 153. Seo JS, Whang D, Lee H, Jun SI, Oh J, Jeon YJ, Kim K (2000) fection: ironing out the defects in metal-organic framework A homochiral metal-organic porous material for enantioselective UiO-66. Chem Mater 26:4068–4071 separation and catalysis. Nature 404:982–986 137. Shearer GC, Chavan S, Bordiga S, Svelle S, Olsbye U, Lillerud 154. Evans OR, Ngo HL, Lin WB (2001) Chiral porous solids KP (2016) Defect engineering: tuning the porosity and compo- based on lamellar lanthanide phosphonates. J Am Chem Soc sition of the metal-organic framework Uio-66 via modulated 123:10395–10396 synthesis. Chem Mater 28:3749–3761 155. Wu CD, Hu A, Zhang L, Lin WB (2005) Homochiral porous 138. Shearer GC, Vitillo JG, Bordiga S, Svelle S, Olsbye U, Lillerud metal-organic framework for highly enantioselective heterogene- KP (2016) Functionalizing the defects: postsynthetic ligand ous asymmetric catalysis. J Am Chem Soc 127:8940–8941 exchange in the metal organic framework UiO-66. Chem Mater 156. Cho SH, Ma BQ, Nguyen ST, Hupp JT, Albrecht-Schmitt TE 28:7190–7193 (2006) A metal-organic framework material that functions as an 139. Karagiaridi O, Vermeulen NA, Klet RC, Wang TC, Moghadam enantioselective catalyst for olefin epoxidation. Chem Commun PZ, Al-Juaid SS, Stoddart JF, Hupp JT, Farha OK (2015) Func- 24:2563–2565 tionalized defects through solvent-assisted linker exchange: 157. Banerjee M, Das S, Yoon M, Choi HJ, Hyun MH, Park SM, Seo synthesis, characterization, and partial postsynthesis elabora- G, Kim K (2009) Postsynthetic modification switches an achi- tion of a metal-organic framework containing free carboxylic ral framework to catalytically active homochiral metal-organic acid moieties. Inorg Chem 54:1785–1790 porous materials. J Am Chem Soc 131:7524–7525 3+ 2+/3+ 2+/3+ 2+ 140. Brozek CK, Dinca M (2013) T i-, V-, Cr-, Mn -, 158. Ma LQ, Falkowski JM, Abney C, Lin WB (2010) A series of iso- 2+ and Fe -substituted MOF-5 and redox reactivity in Cr- and reticular chiral metal-organic frameworks as a tunable platform Fe-MOF-5. J Am Chem Soc 135:12886–12891 for asymmetric catalysis. Nat Chem 2:838–846 141. Kim M, Cahill JF, Fei HH, Prather KA, Cohen SM (2012) Post- 159. Lun DJ, Waterhouse GIN, Telfer SG (2011) A general thermola- synthetic ligand and cation exchange in robust metal-organic bile protecting group strategy for organocatalytic metal-organic frameworks. J Am Chem Soc 134:18082–18088 frameworks. J Am Chem Soc 133:5806–5809 142. Gu ZG, Heinke L, Wöll C, Neumann T, Wenzel W, Li Q, Fink 160. Dang DB, Wu PY, He C, Xie Z, Duan CY (2010) Homochiral K, Gordan OD, Zahn DRT (2015) Experimental and theoretical metal-organic frameworks for heterogeneous asymmetric cataly- investigations of the electronic band structure of metal-organic sis. J Am Chem Soc 132:14321–14323 frameworks of HKUST-1 Type. Appl Phys Lett 107:5 161. Ma LQ, Abney C, Lin WB (2009) Enantioselective catalysis 143. Wang ZB, Sezen H, Liu JX, Yang CW, Roggenbuck SE, Pei- with homochiral metal-organic frameworks. Chem Soc Rev kert K, Froba M, Mavrantonakis A, Supronowicz B, Heine T, 38:1248–1256 Gliemann H, Wöll C (2015) Tunable coordinative defects in 162. Dybtsev DN, Nuzhdin AL, Chun H, Bryliakov KP, Talsi EP, UHM-3 surface-mounted MOFs for gas adsorption and separa- Fedin VP, Kim K (2006) A homochiral metal-organic material tion: a combined experimental and theoretical study. Micropo- with permanent porosity, enantioselective sorption properties, rous Mesoporous Mater 207:53–60 and catalytic activity. Angew Chem-Int Ed 45:916–920 144. Shekhah O, Swaidan R, Belmabkhout Y, du Plessis M, Jacobs 163. Li G, Yu WB, Ni J, Liu TF, Liu Y, Sheng EH, Cui Y (2008) T, Barbour LJ, Pinnau I, Eddaoudi M (2014) The liquid phase Self-assembly of a homochiral nanoscale metallacycle from a epitaxy approach for the successful construction of ultra-thin metallosalen complex for enantioselective separation. Angew and defect-free ZIF-8 membranes: pure and mixed gas trans- Chem-Int Ed 47:1245–1249 port study. Chem Commun 50:2089–2092 164. Nickerl G, Henschel A, Grunker R, Gedrich K, Kaskel S (2011) 145. Liu GP, Chernikova V, Liu Y, Zhang K, Belmabkhout Y, Chiral metal-organic frameworks and their application in asym- Shekhah O, Zhang C, Yi SL, Eddaoudi M, Koros WJ (2018) metric catalysis and stereoselective separation. Chem Ing Tech Mixed matrix formulations with MOF molecular sieving for 83:90–103 key energy-intensive separations. Nat Mater 17:283–289 165. Liu Y, Xuan WM, Cui Y (2010) Engineering homochiral metal- 146. Wang ZB, Knebel A, Grosjean S, Wagner D, Brase S, Wöll organic frameworks for heterogeneous asymmetric catalysis and C, Caro J, Heinke L (2016) Tunable molecular separation by enantioselective separation. Adv Mater 22:4112–4135 nanoporous membranes. Nat Commun 7:7 166. Gu ZG, Zhan CH, Zhang J, Bu XH (2016) Chiral chemistry of 147. Muller K, Knebel A, Zhao FL, Bleger D, Caro J, Heinke metal-camphorate frameworks. Chem Soc Rev 45:3122–3144 L (2017) Switching thin films of azobenzene-containing 1 3 2222 Y. Wang, C. Wöll 167. Liu B, Shekhah O, Arslan HK, Liu JX, Wöll C, Fischer RA 181. Zhang WN, Lu G, Cui CL, Liu YY, Li SZ, Yan WJ, Xing C, (2012) Enantiopure metal-organic framework thin films: ori - Chi YR, Yang YH, Huo FW (2014) A family of metal-organic ented SURMOF growth and enantioselective adsorption. Angew frameworks exhibiting size-selective catalysis with encapsulated Chem-Int Ed 51:807–810 noble-metal nanoparticles. Adv Mater 26:4056–4060 168. Gu ZG, Burck J, Bihlmeier A, Liu JX, Shekhah O, Weidler PG, 182. Lu G, Li SZ, Guo Z, Farha OK, Hauser BG, Qi XY, Wang Y, Azucena C, Wang ZB, Heissler S, Gliemann H, Klopper W, Wang X, Han SY, Liu XG, DuChene JS, Zhang H, Zhang QC, Ulrich AS, Wöll C (2014) Oriented circular dichroism analysis Chen XD, Ma J, Loo SCJ, Wei WD, Yang YH, Hupp JT, Huo of chiral surface-anchored metal-organic frameworks grown by FW (2012) Imparting functionality to a metal-organic framework liquid-phase epitaxy and upon loading with chiral guest com- material by controlled nanoparticle encapsulation. Nat Chem pounds. Chem-Eur J 20:9879–9882 4:310–316 169. Gu ZG, Grosjean S, Brase S, Wöll C, Heinke L (2015) Enanti- 183. Zhan WW, Kuang Q, Zhou JZ, Kong XJ, Xie ZX, Zheng LS oselective adsorption in homochiral metal-organic frameworks: (2013) Semiconductor@metal-organic framework core-shell the pore size influence. Chem Commun 51:8998–9001 heterostructures: a case of ZnO@ZIF-8 nanorods with selective 170. Gu ZG, Fu H, Neumann T, Xu ZX, Fu WQ, Wenzel W, Zhang photoelectrochemical response. J Am Chem Soc 135:1926–1933 L, Zhang J, Wöll C (2016) Chiral porous metacrystals: employ- 184. Li XY, Pi YH, Hou QQ, Yu H, Li Z, Li YW, Xiao J (2018) Amor- ing liquid-phase epitaxy to assemble enantiopure metal-organic phous TiO @NH -MIL-125(Ti) homologous MOF-encapsulated 2 2 nanoclusters into molecular framework pores. ACS Nano heterostructures with enhanced photocatalytic activity. Chem 10:977–983 Commun 54:1917–1920 171. Hermes S, Schroter MK, Schmid R, Khodeir L, Muhler M, 185. Esken D, Noei H, Wang YM, Wiktor C, Turner S, Van Tendeloo Tissler A, Fischer RW, Fischer RA (2005) Metal@Mof: load- G, Fischer RA (2011) Zno@Zif-8: stabilization of quantum ing of highly porous coordination polymers host lattices by confined ZnO nanoparticles by a zinc methylimidazolate frame- metal organic chemical vapor deposition. Angew Chem-Int Ed work and their surface structural characterization probed by CO 44:6237–6241 adsorption. J Mater Chem 21:5907–5915. 172. Esken D, Turner S, Lebedev OI, Van Tendeloo G, Fischer RA 186. Guo W, Chen Z, Yang CW, Neumann T, Kuebel C, Wenzel W, (2010) Au@ZIFs: stabilization and encapsulation of cavity-size Welle A, Pfleging W, Shekhah O, Wöll C, Redel E (2016) Bi O 2 3 matching gold clusters inside functionalized zeolite imidazolate nanoparticles encapsulated in surface mounted metal-organic frameworks, Zifs. Chem Mater 22:6393–6401 framework thin films. Nanoscale 8:6468–6472 173. Muller M, Turner S, Lebedev OI, Wang YM, van Tendeloo G, 187. Domenech A, Garcia H, Domenech-Carbo MT, Xamena F (2007) Fischer RA (2011) Au@MOF-5 and Au/MOx@MOF-5 (M = Electrochemistry of metal-organic frameworks: a description Zn, Ti; X = 1, 2): preparation and microstructural characterisa- from the voltammetry of microparticles approach. J Phys Chem tion. Eur J Inorg Chem 2011:1876–1887 C 111:13701–13711 174. Hermannsdorfer J, Friedrich M, Miyajima N, Albuquerque RQ, 188. Babu KF, Kulandainathan MA, Katsounaros I, Rassaei L, Bur- Kummel S, Kempe R (2012) Ni/Pd@Mil-101: synergistic cataly- rows AD, Raithby PR, Marken F (2010) Electrocatalytic activ- sis with cavity-conform Ni/Pd nanoparticles. Angew Chem-Int ity of basolite (Tm) F300 metal-organic-framework structures. Ed 51:11473–11477 Electrochem Commun 12:632–635 175. Zhu QL, Li J, Xu Q (2013) Immobilizing metal nanoparticles to 189. Dragasser A, Shekhah O, Zybaylo O, Shen C, Buck M, Wöll C, metal-organic frameworks with size and location control for opti- Schlettwein D (2012) Redox mediation enabled by immobilised mizing catalytic performance. J Am Chem Soc 135:10210–10213 centres in the pores of a metal-organic framework grown by liq- 176. Huang YB, Zhang YH, Chen XX, Wu DS, Yi ZG, Cao R (2014) uid phase epitaxy. Chem Commun 48:663–665 Bimetallic alloy nanocrystals encapsulated in ZIF-8 for synergis- 190. Mugnaini V, Tsotsalas M, Bebensee F, Grosjean S, Shahnas A, tic catalysis of ethylene oxidative degradation. Chem Commun Brase S, Lahann J, Buck M, Wöll C (2014) Electrochemical 50:10115–10117 investigation of covalently post-synthetic modified surgel coat- 177. Zhou JJ, Wang P, Wang CX, Goh YT, Fang Z, Messersmith ings. Chem Commun 50:11129–11131 PB, Duan HW (2015) Versatile core-shell nanoparticle@metal- 191. Liu JX, Paradinas M, Heinke L, Buck M, Ocal C, Mugnaini organic framework nanohybrids: exploiting mussel-inspired V, Wöll C (2016) Film quality and electronic properties of a polydopamine for tailored structural Integration. ACS Nano surface-anchored metal-organic framework revealed by using a 9:6951–6960 multi-technique approach. ChemElectroChem 3:713–718 178. Chen LY, Chen XD, Liu HL, Li YW (2015) Encapsulation of 192. Ye L, Liu JX, Gao Y, Gong CH, Addicoat M, Heine T, Wöll C, mono- or bimetal nanoparticles inside metal-organic frame- Sun LC (2016) Highly oriented MOF thin film-based electro- works via in situ incorporation of metal precursors. Small catalytic device for the reduction of CO to CO exhibiting high 11:2642–2648 faradaic efficiency. J Mater Chem A 4:15320–15326. 179. Rosler C, Esken D, Wiktor C, Kobayashi H, Yamamoto T, Mat- 193. Zhang LP, Cui P, Yang HB, Chen JZ, Xiao FX, Guo YY, Liu Y, sumura S, Kitagawa H, Fischer RA (2014) Encapsulation of Zhang WN, Huo FW, Liu B (2016) Metal-organic frameworks as bimetallic nanoparticles into a metal-organic framework: prepa- promising photosensitizers for photoelectrochemical water split- ration and microstructure characterization of Pd/Au@ZIF-8. Eur ting. Adv Sci 3:6 J Inorg Chem 2014:5514–5521 194. Liu JX, Zhou WC, Liu JX, Howard I, Kilibarda G, Schlabach S, 180. Rosler C, Dissegna S, Rechac VL, Kauer M, Guo PH, Turner S, Coupry D, Addicoat M, Yoneda S, Tsutsui Y, Sakurai T, Seki Ollegott K, Kobayashi H, Yamamoto T, Peeters D, Wang YM, S, Wang ZB, Lindemann P, Redel E, Heine T, Wöll C (2015) Matsumura S, Van Tendeloo G, Kitagawa H, Muhler M, Xamena Photoinduced charge-carrier generation in epitaxial MOF thin F, Fischer RA (2017) Encapsulation of bimetallic metal nano- films: high efficiency as a result of an indirect electronic band particles into robust zirconium-based metal-organic frameworks: gap? Angew Chem-Int Ed 54:7441–7445 evaluation of the catalytic potential for size-selective hydrogena- tion. Chem-Eur J 23:3583–3594 1 3

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Chemical Reactions at Isolated Single-Sites Inside Metal–Organic Frameworks

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Chemical Reactions at Isolated Single-Sites Inside Metal–Organic Frameworks

Chemical Reactions at Isolated Single-Sites Inside Metal–Organic Frameworks

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