Isomerism and reactivity of nickel(ii) acetylacetonate bis(thiosemicarbazone) complexes.

Author(s) Bilyj, J.K.; Riley, M.J.; Bernhardt, P.V.
Journal Dalton Trans
Date Published 2018 Feb 06
Abstract

The complexation of nickel(ii) with acetylacetonate bis(thiosemicarbazone) NS ligands with varying substituents has revealed that two isomers can exist independently in solution. These isomers differ according to the formation of either a 5,6,5-membered (symmetric) or a 4,7,5-membered (asymmetric) chelate ring arrangement. These two isomers have distinctly different properties. The symmetric complex (sym-[Ni(acacR)]) is unstable in the presence of air and slowly converts to the oxidised analogue sym-[Ni(acacRO)] with a carbonyl group installed at the apical C-atom. The mechanism of this O-atom transfer reaction is still unclear but kinetic and spectroelectrochemical experiments in addition to Density Functional Theory calculations have identified a single electron oxidised Ni-ligand radical complex as a key intermediate. By contrast the asymmetric complex, asym-[Ni(acacR)] is inert to ligand oxidation.

DOI 10.1039/c7dt04337f
ISSN 1477-9234
Citation Bilyj JK, Riley MJ, Bernhardt PV. Isomerism and reactivity of nickel(ii) acetylacetonate bis(thiosemicarbazone) complexes. Dalton Trans. 2018;47(6):2018-2030.

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