Publikationsrepositorium - Helmholtz-Zentrum Dresden-Rossendorf
1 PublikationAromatic and aliphatic hydrocarbon hydroxylation via a formally Ni(IV)=O oxidant
Heim, P.; Gericke, R.; Spedalotto, G.; Lovisari, M.; Farquhar, E. R.; McDonald, A. R.
Abstract
The reaction of (NMe₄)₂[Ni(II)(LPh)(OAc)] (1[OAc], LPh = 2,2’,2’’-nitrilo-tris-(N-phenylacetamide); OAc = acetate) with 3-chloroperoxybenzoic acid (m-CPBA) resulted in the formation of a self-hydroxylated Ni(III)- phenolate complex, 2, where one of the phenyl groups of LPh underwent hydroxylation. 2 was characterised by UV-Vis, EPR, and XAS spectroscopies and ESI-MS. 2 decayed to yield a previously characterised Ni(II)-phenolate complex, 3. We postulate that self-hydroxylation was mediated by a formally Ni(IV)=O oxidant, formed from the reaction of 1[OAc] with m-CPBA, which undergoes electrophilic aromatic substitution to yield 2. This is supported by an analysis of the kinetic and thermodynamic properties of the reaction of 1[OAc] with m-CPBA. Addition of exogenous hydrocarbon substrates intercepted the selfhydroxylation process, producing hydroxylated products, providing further support for the formally Ni(IV)=O entity. This study demonstrates that the reaction between Ni(II) salts and m-CPBA can lead to potent metal-based oxidants, in contrast to recent studies demonstrating carboxyl radical is a radical free-chain reaction initiator in Ni(II)/m-CPBA hydrocarbon oxidation catalysis.
Keywords: hydrocarbon hydroxylation; nickel; XANES/EXAFS; electron paramagnetic resonance; quantum chemical calculation
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Dalton Transactions 52(2023), 2663-2671
DOI: 10.1039/D2DT03949D
Cited 1 times in Scopus
Permalink: https://www.hzdr.de/publications/Publ-36510