Cyclopentadienyl Cobalt Complexes as Precatalysts for Electrocatalytic Hydrogen Evolution. Issue 20 (31st May 2017)

• Record Type: Journal Article
• Authors: Waldie, Kate M.; Kim, Sung‐Kwan; Ingram, Andrew J.; Waymouth, Robert M.
• Is Part Of: European journal of inorganic chemistry. Issue 20(2017)
• Page Start: 2755
• Page End: 2761
• Publication Date: 2017-05-31
• Subjects: Hydrogen -- Cobalt -- Proton reduction -- Electrochemistry; Chemistry, Inorganic -- Periodicals; Organometallic chemistry -- Periodicals; Bioinorganic chemistry -- Periodicals; Solid state chemistry -- Periodicals; 546
• DOI: 10.1002/ejic.201700188
• Languages: English
• ISSNs: 1434-1948

Abstract

Abstract : Electrocatalytic hydrogen evolution is reported with a series of dicationic cobalt complexes [CpCo(N ^ N)(CH3 CN)](ClO4 )2 (Cp = cyclopentadienyl; N ^ N = bipyridine, pyrazolylpyridine, phenylazopyridine) using N, N ‐dimethylformamidinium buffer as the proton source in acetonitrile. The catalytic current profiles obtained for each complex are very similar to each other with overpotentials ranging from 1.2 to 1.4 V, which suggests a common active catalytic species. Further electrochemical studies demonstrate that these complexes are unstable under electrocatalytic conditions: the bidentate nitrogen ligand is readily lost upon reduction in the presence of acid, initially generating [CpCo(CH3 CN)3 ] +, which undergoes further decomposition to surface‐adsorbed species that are responsible for the observed electrocatalysis. Abstract : A series of dicationic cobalt complexes undergoes ligand loss and further transformations under acidic conditions at reducing potentials, leading to the deposition of adsorbed species on the electrode surface. These heterogeneous deposits are active for electrocatalytic proton reduction in acetonitrile.