Bonding in the ground state and excited states of copper-alkene complexes

Abstract

The ground state and 1B2 excited state of Cu(C2H4)+ and of CuX(C2H4) (X = F, Cl) have been investigated by the Hartree-Fock-Slater (HFS) method. The main metal-ligand interactions in the ground state are ethene π → Cu 4s donation and Cu 3dπ → ethene π* backdonation, which have comparable contributions to the metal-ligand bond strength. The excitation of CuX(C2H4) does not involve an alkene π → metal charge transfer (LMCT), but instead is metal 3d → alkene π* charge transfer (MLCT) in character. The implications for the photochemistry of olefin-copper(I) complexes are discussed.