Bonding and the role of electrostatics in driving C-C bond formation in high valent organocopper compounds.

The electronic structures and contrasting reactivity of [Cu(CF 3 ) 4 ] - and [Cu(CF 3 ) 3 (CH 3 )] - were probed using coupled cluster and ab initio valence bond calculations. The Cu-C bonds in these complexes were found to be charge shift bonds. A key finding is that electrostatics likely prevent [Cu(CF 3 ) 4 ] - from accessing a productive transition state for C-C bond formation while promote one for [Cu(CF 3 ) 3 (CH 3 )] - . These results therefore highlight essential design criteria for Cu-mediated C-C/C-heteroatom bond formation.