“…16,17 One of the most intensively studied types of complexes is the copper(I) species having a 2,9-disubstituted 1,10-phenanthroline ligand and a diphosphine ligand. 18 We previously reported a series of copper complexes (1a, 2a, and 3a shown in Scheme 1) bearing dmp (= 2,9dimethyl-1,10-phenanthlorine) and a diphosphine ligand. 19 Armaroli et al reported that a complex [Cu(dmpp)(DPEphos)] + , where dmpp and DPEphos are 2,9-dimethyl-4,7-diphenyl-1,10phenanthroline and 2,2′-bis(diphenylphosphino)diphenyl ether, respectively, shows high-quantum yield luminescence in solution.…”