Probing the effects of steric bulk on the solution-phase behaviour and redox chemistry of cobalt-diimine complexes

Symes, M. D. and Wilson, C. (2018) Probing the effects of steric bulk on the solution-phase behaviour and redox chemistry of cobalt-diimine complexes. Supramolecular Chemistry, 30(9), pp. 742-750. (doi:10.1080/10610278.2017.1373195)

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Abstract

Cobalt-diimine complexes are important structural and redox-active elements in supramolecular assemblies. However, functionalisation of the diimine ligand adjacent to the N-donor atoms can affect dramatically the types of Co-diimine complexes that can form and their redox activity. Herein, we compare the solution phase and redox chemistry of Co(II) complexes with 1,10-phenanthroline, 5,5′-dimethyl-2,2′-bipyridine and 2,9-dimethyl-1,10-phenanthroline (neocuproine). In acetonitrile solutions containing Co(NO3)2 and neocuproine, the dominant species is the mono-diimine complex [Co(neocuproine)(NO3)(CH3CN)2]+. This complex cannot be oxidised, either electrochemically nor with iodine. We rationalise this behaviour by considering the steric constraints placed upon the metal centre by the bulky methyl substituents on the neocuproine ligand. Furthermore, from solutions of [Co(neocuproine)(NO3)(CH3CN)2]+, crystals of formula [Co(neocuproine)2(NO3)]+·[Co(neocuproine)(NO3)3]− can be obtained. We believe that this work will guide the development of Co-diimine supramolecular assemblies by highlighting the extent to which substituents close to the N-donor atoms affect which species form in solution, and their likely redox activity.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Wilson, Dr Claire and Symes, Dr Mark
Authors: Symes, M. D., and Wilson, C.
College/School:College of Science and Engineering > School of Chemistry
Journal Name:Supramolecular Chemistry
Publisher:Taylor and Francis
ISSN:1061-0278
ISSN (Online):1029-0478
Published Online:08 September 2017
Copyright Holders:Copyright © 2017 Informa UK Limited, trading as Taylor & Francis Group
First Published:First published in Supramolecular Chemistry 30(9):742-750
Publisher Policy:Reproduced in accordance with the copyright policy of the publisher
Data DOI:10.5525/gla.researchdata.449

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
714601Driving energetically uphill processes using metal-ligand coordination complexesMark SymesThe Royal Society (ROYSOC)UF150104CHEM - CHEMISTRY