Synthesis, Isomerization and Electrocatalytic Properties of Thiolate‐Bridged Dicobalt Hydride Complexes with Different Substituents. Issue 28 (21st July 2020)

• Record Type: Journal Article
• Authors: Wang, Chunlong; Li, Jianzhe; Yang, Dawei; Tong, Peng; Sun, Puhua; Wang, Baomin; Qu, Jingping
• Is Part Of: European journal of inorganic chemistry. Issue 28(2020)
• Page Start: 2757
• Page End: 2764
• Publication Date: 2020-07-21
• Subjects: Cobalt -- S‐Ligands -- Biomimetic synthesis -- Electrochemistry; Chemistry, Inorganic -- Periodicals; Organometallic chemistry -- Periodicals; Bioinorganic chemistry -- Periodicals; Solid state chemistry -- Periodicals; 546
• DOI: 10.1002/ejic.202000369
• Languages: English
• ISSNs: 1434-1948

Abstract

Abstract : Through different pathways, two unsaturated thiolate‐bridged Co II Co II complexes [Cp*Co(µ‐SR)2 CoCp*] (1, R = Ph; 3, R = i Pr, Cp* = η 5 ‐C5 Me5 ) were successfully synthesized. Interaction of complexes 1 or 3 with HBF4 resulted in oxidative addition to give the corresponding thiolate‐bridged Co III Co III hydride bridged complexes 4[BF4 ] and 5[BF4 ] . 1 H NMR spectroscopic results indicate there exist two conformational isomers after protonation, in which the substituents on the thiolate ligands arranged in a symmetric or unsymmetric geometry. Interestingly, major sym ‐4[BF4 ] can irreversibly convert into minor unsym ‐4[BF4 ] at 30 °C evidenced by time‐dependent 1 H NMR spectroscopy. Surprisingly, two isomers of 5[BF4 ] remain a dynamic equilibrium from –80 to 30 °C corroborated by variable‐temperature 1 H NMR spectra. Furthermore, these thiolate‐bridged dicobalt hydride complexes are proved to be catalysts for electrocatalytic proton reduction by cyclic voltammetry. Notably, complex 5[BF4 ] exhibits better catalytic activity, which highlights the importance of the flexibility of the auxiliary ligand. Abstract : A fascinating dynamic equilibrium of conformational isomerization was observed in an alkyl thiolate‐bridged dicobalt hydride complex, which is proved to be a catalyst for proton reduction to hydrogen evolution.