Dalton Transactions

doi: 10.1039/D2DT90106Dpmid: N/A

doi: 10.1039/D2DT90107Bpmid: N/A

De, Diptiman; Sahoo, Prithidipa

doi: 10.1039/d2dt00994cpmid: 35726742

Metalorganic frameworks (MOFs) are porous crystalline materials consisting of one-, two-, or three-dimensional networks created by metal ions/clusters and multidentate organic linkers through coordination bonding. MOFs are one of the most favorable candidates for biological applications such as wound dressings, cardiac prosthesis, tissue engineering, bioimaging, and drug delivery and as cancer theranostic systems due to their high surface area and porosity for the high loading of therapeutic agents and facile modification of their physical (e.g., pore size and shape) and chemical properties. Drug delivery involves the administration of drugs using a suitable carrier for achieving treatment without unwanted side effects. In the last few years, several types of MOFs have been synthesized including Zn-based MOFs, MIL series MOFs, and Zr-based MOFs and evaluated for their use in different biomedical fields, especially drug delivery. After Fe, zinc is the second most available element in the body, and hence Zn-based MOFs can be considered enduring platforms for various biomedical uses, especially drug delivery applications. MIL series composites and Zr-based biomaterials are also suggested for several biomedical applications due to their good mechanical properties, biocompatibility, and bioactivity. This review highlights the different types of Zn-based and MIL series MOFs that have been used as suitable pH-responsive drug delivery systems and summarizes the Zr-based MOFs that have been used as suitable pH-responsive or reverse pH-responsive drug delivery systems and also discuss their drug-releasing phenomenon at different pH ranges.

Zhang, Yi-Pin; Zheng, You-Xuan

doi: 10.1039/d2dt01582jpmid: 35737413

Materials with circularly polarized luminescence properties have attracted wide attention in recent years. One of the most important applications of these materials is for circularly polarized organic light emitting diodes (CP-OLEDs), which have potential application in 3D displays. Chiral conjugated polymers, small organic molecules and metal complexes have already been employed as emitters for CP-OLEDs. Benefiting from the ability to harvest both singlet and triplet excitons, chiral phosphorescent metal complexes always show outstanding device performance. In this article we briefly discuss the recent progress, current challenges and out look of chiral phosphorescent metal complexes.

Fontana, Liniquer A.; Rigolin, Vitor H.; Ribeiro, Marcos A.; Barros, Wdeson P.; Megiatto, Jackson D.

doi: 10.1039/d2dt01095jpmid: 35708623

We report a synthetic strategy that allows for the preparation of sterically encumbered heteroleptic Ru(ii)porphyrinates with the desired configuration of stable/inert and weak/labile axial ligands to direct reactions between substrates to exclusively occur at the sterically encumbered face. To demonstrate the method, we describe the synthesis of a strapped-Ru(ii)porphyrinate bearing a stable/inert triphenylphosphine (PPh3) bulky axial ligand coordinated exo to the central cavity and a weak/labile methanol molecule coordinated at the internal axial position. With this axial ligand configuration, the reported Ru(ii)porphyrinate exclusively promotes carbene transfer reactions to olefins through the central cavity, which has been verified by the selective formation of cycloprane-linked [2]rotaxanes.

Dong, Wenjing; Yang, Dawei; Mei, Tao; Wang, Baomin; Qu, Jingping

doi: 10.1039/d2dt01534jpmid: 35722932

A well-defined thiolate-bridged cobaltruthenium complex is demonstrated to reversibly bind N2 by modulation of the auxiliary phosphine ligand, which is evidenced by time-dependent 1H NMR spectroscopy at different temperatures. Notably, this heterobimetallic system represents the first example that can realize N2 coordination on a sulfur-rich CoRu cooperative scaffold.

Komuro, Takashi; Mochizuki, Daiki; Hashimoto, Hisako; Tobita, Hiromi

doi: 10.1039/d2dt01227hpmid: 35735002

Unsaturated 16-electron iridium and rhodium complexes bearing a silyl-bipyridine-based SiNN-pincer ligand (BpySiNN) were synthesised and characterised by X-ray crystallography and NMR spectroscopy. The iridium-BpySiNN complex facilitated the catalytic C(sp2)H borylation of arenes to give arylboronate esters in high yields (93%) under mild conditions (40 C).

Du, Weixin; Liu, Yufeng; Sun, Junjun; Wang, Haiying; Yang, Guoping; Zhang, Dongdi

doi: 10.1039/d2dt01332kpmid: 35678129

Functionalization with belt lanthanide groups allows for the crystallization and structural characterization of homometallic selenotantalates, CsK[Ln(H2O)6Se4(TaO2)6(OH)3O18]nH2O (Ln = Eu/Gd, n = 14 (STD-Eu, STD-Gd) and Ln = Lu, n = 12 (STD-Lu)). The basket-shaped {Se4(TaO2)6} archetype is assembled in a simple one-pot reaction of Na2SeO3 and K8[Ta6O19]17H2O in acidic aqueous medium (pH 2) and in the presence of hydrogen peroxide. This unit has been proven to be an effective precursor for the preparation of a range of new POMs containing the {Se4(TaO2)6} unit. The lanthanide derivatives STD-Eu, STD-Gd and STD-Lu have been fully characterized with single-crystal X-ray diffraction, IR spectroscopy, TG analysis and PXRD in the solid state. The photoluminescence and lifetime decay behaviours of STD-Eu have been studied at room temperature, and the photoluminescence spectrum displays the characteristic emission of the Eu3+ cation. In addition, the catalytic activities of STD-Eu, STD-Gd and STD-Lu on the reaction of phthalic anhydride with phenylamines have been investigated. STD-Eu shows good catalytic activities for imidation reactions.

Aldrich, Kelly E.; Popov, Ivan A.; Root, Harrison D.; Batista, Enrique R.; Greer, Samuel M.; Kozimor, Stosh A.; Lilley, Laura M.; Livshits, Maksim Y.; Mocko, Veronika; Janicke, Michael T.; Scott, Brian L.; Stein, Benjamin W.; Yang, Ping

doi: 10.1039/d1dt03887gpmid: 35739082

Developing chelators that strongly and selectively bind rare-earth elements (Sc, Y, La, and lanthanides) represents a longstanding fundamental challenge in inorganic chemistry. Solving these challenges is becoming more important because of increasing use of rare-earth elements in numerous technologies, ranging from paramagnets to luminescent materials. Within this context, we interrogated the complexation chemistry of the scandium(III) (Sc3+) trication with the hexadentate 1,4,7-triazacyclononane-1,4,7-triacetic acid (H3NOTA) chelator. This H3NOTA chelator is often regarded as an underperformer for complexing Sc3+. A common assumption is that metalation does not fully encapsulate Sc3+ within the NOTA3− macrocycle, leaving Sc3+ on the periphery of the chelate and susceptible to demetalation. Herein, we developed a synthetic approach that contradicted those assumptions. We confirmed that our procedure forced Sc3+ into the NOTA3− binding pocket by using single crystal X-ray diffraction to determine the Na[Sc(NOTA)(OOCCH3)] structure. Density functional theory (DFT) and 45Sc nuclear magnetic resonance (NMR) spectroscopy showed Sc3+ encapsulation was retained when the crystals were dissolved. Solution-phase and DFT studies revealed that [Sc(NOTA)(OOCCH3)]1− could accommodate an additional H2O capping ligand. Thermodynamic properties associated with the Sc-OOCCH3 and Sc-H2O capping ligand interactions demonstrated that these capping ligands occupied critical roles in stabilizing the [Sc(NOTA)] chelation complex.

G, Abigail Jennifer; Gao, Yang; Schreckenbach, Georg; Varathan, Elumalai

doi: 10.1039/d2dt01142epmid: 35703365

The separation of minor actinides in their dioxocation (i.e., actinyl) form in high-valence oxidation states requires efficient ligands for their complexation. In this work, we evaluate the complexation properties of actinyls including americyl, curyl, berkelyl, and californyl in their pentavalent and hexavalent oxidation states with the dipyriamethyrin ligand (L) using density functional theory calculations. The calculated bond parameters show shorter AnOyl bonds with covalent character and longer An–N bonds with ionic character. The bonding between the actinyl cation and the ligand anion shows a flow of charges from the ligand to actinyl in all [AnV/VIO2–L]1−/0 complexes. However, across the series, backdonation of charges from the metal to the ligand becomes prominent and stabilizes the complexes. The thermodynamic parameters in the gas phase and solution suggest that the complex formation reaction is spontaneous for [CfV/VIO2–L]1−/0 complexes and spontaneous at elevated temperatures (>298.15 K) for all other complexes. Spin–orbit corrections have a quantitative impact while the overall trend remains the same. Energy decomposition analysis (EDA) reveals that the interaction between actinyl and the ligand is mainly due to electrostatic contributions that decrease from Am to Cf along with an increase in orbital contributions due to the backdonation of charges from the actinyl metal center to the ligand that greatly stabilizes the Cf complex. The repulsive Pauli energy contribution is observed to increase in the case of [AnVO2–L]1− complexes from Am to Cf while a decrease is observed among [AnVIO2–L]0 complexes, showing minimum repulsion in [CfVIO2–L]0 complex formation. Overall, the hexavalent actinyl complexes show greater stability (increasing from Am to Cf) than their pentavalent counterparts.