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Synthesis, Isomerization and Electrocatalytic Properties of Thiolate‐Bridged Dicobalt Hydride Complexes with Different Substituents
Author(s) -
Wang Chunlong,
Li Jianzhe,
Yang Dawei,
Tong Peng,
Sun Puhua,
Wang Baomin,
Qu Jingping
Publication year - 2020
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.202000369
Subject(s) - chemistry , isomerization , hydride , protonation , cyclic voltammetry , catalysis , nuclear magnetic resonance spectroscopy , ligand (biochemistry) , medicinal chemistry , proton nmr , stereochemistry , nmr spectra database , crystallography , metal , electrochemistry , spectral line , organic chemistry , ion , electrode , biochemistry , receptor , physics , astronomy
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 ‐C 5 Me 5 ) were successfully synthesized. Interaction of complexes 1 or 3 with HBF 4 resulted in oxidative addition to give the corresponding thiolate‐bridged Co III Co III hydride bridged complexes 4[BF 4 ] and 5[BF 4 ] . 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[BF 4 ] can irreversibly convert into minor unsym ‐ 4[BF 4 ] at 30 °C evidenced by time‐dependent 1 H NMR spectroscopy. Surprisingly, two isomers of 5[BF 4 ] 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[BF 4 ] exhibits better catalytic activity, which highlights the importance of the flexibility of the auxiliary ligand.