Mechanistic differences between "reductive" and "oxidative" heterolysis of metal-carbon G bonds

Volumes of activation, A V, for the heterolysis reactions of copper complexes with metal-carbon a bonds, rfc. [(H2O)5Cum-R]2t (R = CH2C(V or CHCV) and [LCuII-R]t (L = 2,5,8,1 l-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 [LCun-CHj]+ was determined. The results reveal the different roles of the solvent (water) in the transition states for oxidative and reductive heterolysis reactions.