Guillaumont M, Fourré I, Pilmé J, Halbert S, Gérard H. Triggering Electron Transfer in Co(I) Dimers: Computational Evidences for a Reversible Disproportionation Mechanism.
Chemphyschem 2021;
22:788-795. [PMID:
33529486 DOI:
10.1002/cphc.202000965]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Revised: 02/01/2021] [Indexed: 11/09/2022]
Abstract
An inner-sphere disproportionation mechanism of the Co(I) precursor CoCl(PPh3 )3 is described through a Density Functional Theory study. The essential role of oleylamine in this process is unravelled. A detailed analysis of the electronic structure of Cobalt dimers of the general formula Co2 Cl2 Ln (L=NH3 and PH3 ) demonstrates that electron transfer is triggered by asymetric coordination of amine and phosphine to stabilize a mixed-valence Co(II)-Co(0) dimer. This is consistent with the HSAB statement that both amine and phosphine ligands are required to stabilize the reaction products, respectively Co(II) and Co(0) centers. We propose a quasi-athermic multi-step disproportionation mechanism with low activation barriers where the electron transfer goes through simple ligand exchanges between Co.
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