Papanikolaou, M. G., Elliott, A., McAllister, J. , Gallos, J. K., Keramidas, A. D., Kabanos, T. A., Sproules, S. and Miras, H. N. (2020) Electrocatalytic hydrogen production by dinuclear cobalt(ii) compounds containing redox-active diamidate ligands: a combined experimental and theoretical study. Dalton Transactions, 49(44), pp. 15718-15730. (doi: 10.1039/D0DT02617D) (PMID:33146215)
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Abstract
The chiral dicobalt(II) complex [CoII2(μ2-L)2] (1) (H2L = N2,N6-di(quinolin-8-yl)pyridine-2,6-dicarboxamide) and its tert-butyl analogue [CoII2(μ2-LBu)2] (2) were synthesized and structurally characterized. Addition of one equivalent of AgSbF6 to the dichloromethane solution of 1 and 2 resulted in the isolation of the mixed-valent dicobalt(III,II) species [CoIIICoII(μ2-L)2]SbF6 (3) and [CoIIICoII(μ2-LBu)2]SbF6 (4). Homovalent 1 and 2 exhibited catalytic activity towards proton reduction in the presence of acetic acid (AcOH) as the substrate. The complexes are stable in solution while their catalytic turnover frequency is estimated at 10 and 34.6 h−1 molcat−1 for 1 and 2, respectively. Calculations reveal one-electron reduction of 1 is ligand-based, preserving the dicobalt(II) core and activating the ligand toward protonation at the quinoline group. This creates a vacant coordination site that is subsequently protonated to generate the catalytically ubiquitous Co(III) hydride. The dinuclear structure persists throughout where the distal Co(II) ion modulates the reactivity of the adjacent metal site by promoting ligand redox activity through spin state switching.
Item Type: | Articles |
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Additional Information: | The research work was supported by the Hellenic Foundation for Research and Innovation (HFRI) under the HFRI PhD Fellowship grant (Fellowship Number: 1213). |
Status: | Published |
Refereed: | Yes |
Glasgow Author(s) Enlighten ID: | Sproules, Dr Stephen and Moiras, Professor Haralampos and Elliott, Mr Alexander and McAllister, Mr James |
Authors: | Papanikolaou, M. G., Elliott, A., McAllister, J., Gallos, J. K., Keramidas, A. D., Kabanos, T. A., Sproules, S., and Miras, H. N. |
College/School: | College of Science and Engineering > School of Chemistry |
Journal Name: | Dalton Transactions |
Publisher: | Royal Society of Chemistry |
ISSN: | 1477-9226 |
ISSN (Online): | 1477-9234 |
Published Online: | 28 October 2020 |
Copyright Holders: | Copyright © 2020 The Royal Society of Chemistry |
First Published: | First published in Dalton Transactions 49(44):15718-15730 |
Publisher Policy: | Reproduced under a Creative Commons License |
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