Mechanistic differences between “reductive” and “oxidative” heterolysis of metal–carbon σ bonds

Abstract

Volumes of activation, ΔV^‡, for the heterolysis reactions of copper complexes with metal–carbon σ bonds, viz. [(H₂O)₅Cu^III–R]²⁺ (R = CH₂CO₂⁻ or CHCl₂⁻) and [LCu^II–R]⁺ (L = 2,5,8,11-tetramethyl-2,5,8,11-tetraazadodecane; R = CH₂CO₂⁻), were determined using high pressure pulse-radiolysis techniques. In addition, the volume of activation for the bimolecular decomposition of [LCu^II–CH₃]⁺ was determined. The results reveal the different roles of the solvent (water) in the transition states for oxidative and reductive heterolysis reactions.