Cuprophilicity: Spectroscopic and Structural Evidence for Cu−Cu Bonding Interactions in Luminescent Dinuclear Copper(I) Complexes with Bridging Diphosphane Ligands

The unequivocal assignment of the 3 dσ*→4 pσ metal–metal transition by spectroscopic methods and structural studies reveals the existence of CuI⋅⋅⋅CuI interactions, or cuprophilicity, in discrete binuclear CuI complexes with bridging diphosphane ligands (see picture). It is also shown that the metal–ligand influenced states may dominate the luminescence of the CuI centers.