Angewandte Chemie International Edition

doi: 10.1002/anie.202382611pmid: N/A

Hasegawa, Hiroki; Sakamaki, Daisuke; Fujiwara, Hideki

doi: 10.1002/anie.202302498pmid: 37139930

In this work, we aimed to develop a dicyanomethyl radical that undergoes both reversible C−C bond formation/dissociation and metal‐ligand coordination reactions to combine dynamic covalent chemistry (DCC) based on organic radicals with coordination chemistry. We have previously reported a dicyanomethyl radical conjugated with a triphenylamine (1⋅) that exhibits a monomer/dimer equilibrium between the σ‐bonded dimer (12). We designed and synthesized a novel dicyanomethyl radical with a pyridyl group as a coordination point (2⋅) by replacing the phenyl group of 1⋅ with a 3‐pyridyl group. We showed that 2⋅ is also in an equilibrium with the σ‐bonded dimer (22) in solution and has suitable thermodynamic parameters for application in DCC. 22 coordinates to PdCl2 in a 2 : 2 ratio to selectively form a metallamacrocycle (22)2(PdCl2)2, and its structure was clarified by single crystal X‐ray analysis. Variable‐temperature NMR, ESR, and electronic absorption measurements revealed that (22)2(PdCl2)2 also undergoes the reversible C−C bond formation/dissociation reaction. Ligand‐exchange experiment showed that 22 was liberated from (22)2(PdCl2)2 by the addition of another ligand with a higher affinity for PdII. This work demonstrated that DCC based on dicyanomethyl radicals works orthogonally to metal‐ligand coordination reactions.

Cai, Chao; Liu, Kang; Zhang, Long; Li, Fangbiao; Tan, Yao; Li, Pengcheng; Wang, Yanqiu; Wang, Maoyu; Feng, Zhenxing; Motta Meira, Debora; Qu, Wenqiang; Stefancu, Andrei; Li, Wenzhang; Li, Hongmei; Fu, Junwei; Wang, Hui; Zhang, Dengsong; Cortés, Emiliano; Liu, Min

Zhang, Shucong; Tan, Chunhui; Yan, Ruipeng; Zou, Xifei; Hu, Fei‐Long; Mi, Yan; Yan, Cheng; Zhao, Shenlong

doi: 10.1002/anie.202302795pmid: 37046392

Efficient bifunctional electrocatalysts for hydrogen and oxygen evolution reactions are key to water electrolysis. Herein, we report a built‐in electric field (BEF) strategy to fabricate heterogeneous nickel phosphide‐cobalt nanowire arrays grown on carbon fiber paper (Ni2P‐CoCH/CFP) with large work function difference (ΔΦ) as bifunctional electrocatalysts for overall water splitting. Impressively, Ni2P‐CoCH/CFP exhibits a remarkable catalytic activity for hydrogen and oxygen evolution reactions to obtain 10 mA cm−2, respectively. Moreover, the assembled lab‐scale electrolyzer driven by an AAA battery delivers excellent stability after 50 h electrocatalysis with a 100 % faradic efficiency. Computational calculations combining with experiments reveal the interface‐induced electric field effect facilitates asymmetrical charge distributions, thereby regulating the adsorption/desorption of the intermediates during reactions. This work offers an avenue to rationally design high‐performance heterogeneous electrocatalysts.

Long, Jinguo; Zhao, Ruihua; Cheng, Gui‐Juan; Fang, Xianjie

doi: 10.1002/anie.202304543pmid: 37102634

We herein describe a palladium‐catalyzed hydrocyanation of propiolamides for the stereodivergent synthesis of trisubstituted acrylonitriles. This synthetic method tolerated various primary, secondary and tertiary propiolamides. The cautious selection of a suitable ligand is essential to the success of this stereodivergent process. Control experiments indicate the intermediacy of E‐acrylonitriles, which lead to Z‐acrylonitriles via isomerization. The density functional theory calculations suggests that the bidentate ligand L2 enables a feasible cyclometallation/isomerization pathway for the E to Z isomerization, while the monodentate ligand L1 inhibits the isomerization, leading to divergent stereoselectivity. The usefulness of this method can be demonstrated by the readily derivatization of products to give various E‐ and Z‐trisubstituted alkenes. In addition, the E‐ and Z‐acrylonitrile products have also been successfully employed in cycloaddition reactions.

Xie, Luting; Xu, Kui; Sun, Wenlu; Fan, Yingzhu; Zhang, Junyu; Zhang, Yixiao; Zhang, Hui; Chen, Jun; Shen, Yanbin; Fu, Fang; Kong, Huabin; Wu, Guan; Wu, Jihuai; Chen, Liwei; Chen, Hongwei

Kawashiro, Midori; Mori, Tatsuya; Ito, Masato; Ando, Naoki; Yamaguchi, Shigehiro

doi: 10.1002/anie.202305891pmid: N/A

Ong, Whitney S. Y.; Ji, Ke; Pathiranage, Vishaka; Maydew, Caden; Baek, Kiheon; Villones, Rhiza Lyne E.; Meloni, Gabriele; Walker, Alice R.; Dodani, Sheel C.

doi: 10.1002/anie.202302304pmid: 37059690

Detection of anions in complex aqueous media is a fundamental challenge with practical utility that can be addressed by supramolecular chemistry. Biomolecular hosts such as proteins can be used and adapted as an alternative to synthetic hosts. Here, we report how the mutagenesis of the β‐bulge residues (D137 and W138) in mNeonGreen, a bright, monomeric fluorescent protein, unlocks and tunes the anion preference at physiological pH for sulfate, resulting in the turn‐off sensor SulfOFF‐1. This unprecedented sensing arises from an enhancement in the kinetics of binding, largely driven by position 138. In line with these data, molecular dynamics (MD) simulations capture how the coordinated entry and gating of sulfate into the β‐barrel is eliminated upon mutagenesis to facilitate binding and fluorescence quenching.

Wang, Chuan‐Zhe; Chen, Jie; Li, Qiao‐Hong; Wang, Guan‐E; Ye, Xiao‐Liang; Lv, Jia; Xu, Gang

doi: 10.1002/anie.202302996pmid: 37106275

Pore size plays a critical role in determining the performance of metal‐organic frameworks (MOFs) in catalysis, sensing, and gas storage or separation. However, revealing the pore‐size/property relationship remains extremely challenging because ideal structure models possessing different pore sizes but having the same components are lacking. In this work, a solvent‐coordination directed structure swelling method was developed for modulating the ratio between the large and narrow pore phases of a flexible MOF, MIL‐88B. Pore‐size‐dependent gas sensitivity and selectivity were studied for the first time in the MIL‐88B samples. The optimized MIL‐88B‐20 % sample showed one of the best sensing performances among all the reported MOF‐based H2S‐sensing materials. This work not only provides a method to synthesize ideal structure models for revealing the relationship between pore‐size and properties, but also may inspire the development of high‐performance gas sensing materials.

Wrogemann, Jens Matthies; Lüther, Marco Joes; Bärmann, Peer; Lounasvuori, Mailis; Javed, Ali; Tiemann, Michael; Golnak, Ronny; Xiao, Jie; Petit, Tristan; Placke, Tobias; Winter, Martin

doi: 10.1002/anie.202303111pmid: 37069123

Faradaic reactions including charge transfer are often accompanied with diffusion limitation inside the bulk. Conductive two‐dimensional frameworks (2D MOFs) with a fast ion transport can combine both—charge transfer and fast diffusion inside their porous structure. To study remaining diffusion limitations caused by particle morphology, different synthesis routes of Cu‐2,3,6,7,10,11‐hexahydroxytriphenylene (Cu3(HHTP)2), a copper‐based 2D MOF, are used to obtain flake‐ and rod‐like MOF particles. Both morphologies are systematically characterized and evaluated for redox‐active Li+ ion storage. The redox mechanism is investigated by means of X‐ray absorption spectroscopy, FTIR spectroscopy and in situ XRD. Both types are compared regarding kinetic properties for Li+ ion storage via cyclic voltammetry and impedance spectroscopy. A significant influence of particle morphology for 2D MOFs on kinetic aspects of electrochemical Li+ ion storage can be observed. This study opens the path for optimization of redox active porous structures to overcome diffusion limitations of Faradaic processes.