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Title: | Kinetico-Mechanistic Studies on a Reactive Organocopper(II) Complex: Cu−C Bond Homolysis versus Heterolysis |
Author: | Gonzálvez, Miguel A. Williams, Craig M. Martínez López, Manuel, 1957- Bernhardt, Paul V. |
Keywords: | Reaccions químiques Cinètica química Chemical reactions Chemical kinetics |
Issue Date: | 6-Mar-2023 |
Publisher: | American Chemical Society |
Abstract: | Organocopper(II) reagents are an unexplored frontier of copper catalysis. Despite being proposed as reactive intermediates, an understanding of the stability and reactivity of the CuII-C bond has remained elusive. Two main pathways can be considered for the cleavage mode of a CuII-C bond: homolysis and heterolysis. We recently showed how organocopper(II) reagents can react with alkenes via radical addition, a homolytic pathway. In this work, the decomposition of the complex [CuIILR]+ [L = tris(2- dimethylaminoethyl)amine, Me6tren, R = NCCH2-] in the absence and presence of an initiator (RX, X = Cl, Br) was evaluated. When no initiator was present, first-order CuII-C bond homolysis occurred producing [CuIL]+ and succinonitrile, via radical termination. When an excess of the initiator was present, a subsequent formation of [CuIILX]+ via a second-order reaction was found, which results from the reaction of [CuIL]+ with RX following homolysis. However, when Brønsted acids (R′-OH: R′ = H, Me, Ph, PhCO) were present, heterolytic cleavage of the CuII-C bond produced [CuIIL(OR′)]+ and MeCN. Kinetic studies were undertaken to obtain the thermal (ΔH⧧, ΔS⧧) and pressure (ΔV⧧) activation parameters and deuterium kinetic isotopic effects, which provided an understanding of the strength of the CuII-C bond and the nature of the transition state for the reactions involved. These results reveal possible reaction pathways for organocopper(II) complexes relevant to their applications as catalysts in C-C bond forming reactions. |
Note: | Versió postprint del document publicat a: https://doi.org/10.1021/acs.inorgchem.3c00127 |
It is part of: | Inorganic Chemistry, 2023, vol. 62, num. 11, p. 4662-4671 |
URI: | http://hdl.handle.net/2445/195844 |
Related resource: | https://doi.org/10.1021/acs.inorgchem.3c00127 |
ISSN: | 0020-1669 |
Appears in Collections: | Articles publicats en revistes (Química Inorgànica i Orgànica) |
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