Halide abstraction competes with oxidative addition in the reactions of aryl halides with [Ni(PMenPh(3-n))4]

Funes-Ardoiz, Ignacio and Nelson, David J. and Maseras, Feliu (2017) Halide abstraction competes with oxidative addition in the reactions of aryl halides with [Ni(PMenPh(3-n))4]. Chemistry - A European Journal, 23 (66). pp. 16728-16733. ISSN 1521-3765 (https://doi.org/10.1002/chem.201702331)

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Abstract

Density functional theory (DFT) calculations have been used to study the oxidative addition of aryl halides to complexes of the type [Ni(PMenPh(3-n))4], revealing the crucial role of an open shell singlet transition state for halide abstraction. The formation of NiI versus NiII has been rationalised through the study of three different pathways: (i) halide abstraction by [Ni(PMenPh(3-n))3], via an open shell singlet transition state; (ii) SN2-type oxidative addition to [Ni(PMenPh(3-n))3], followed by phosphine dissociation; and (iii) oxidative addition to [Ni(PMenPh(3-n))2]. For the case of [Ni(PMe3)4], a microkinetic model was used to show that these data are consistent with the experimentally-observed ratios of NiI and NiII. Importantly, [Ni(PMenPh(3-n))2] complexes often have little if any role in the oxidative addition reaction because they are relatively high in energy. The behaviour of [Ni(PR3)4] complexes in catalysis is therefore likely to differ considerably from those based on diphosphine ligands in which two coordinate Ni0 complexes are the key species undergoing oxidative addition.

ORCID iDs

Funes-Ardoiz, Ignacio, Nelson, David J. ORCID logoORCID: https://orcid.org/0000-0002-9461-5182 and Maseras, Feliu;
CORE (COnnecting REpositories)