Bis(2,9-diphenyl-1,10-phenanthroline)copper(I): a copper complex with a long-lived charge-transfer excited state

The title compound, Cu(dpp)2+(dpp = 2,9-diphenyl-1,10-phenanthroline), exhibits long-lived emission at room temperature in solution, and in contrast with copper(I) complexes of less bulky ligands, the emission persists in polar media; a water soluble derivative of Cu(dpp)2+ is luminescent at room temperature in aqueous solution and undergoes efficient redox photochemistry in the presence of electron acceptors.