Luminescent mononuclear mixed ligand complexes of copper(i) with 5-phenyl-2,2′-bipyridine and triphenylphosphine

Reaction of 5-phenyl-2,2′-bipyridine (L) with a mixture of CuI or [Cu(CH3CN)4]BF4 and PPh3 leads to [CuL(PPh3)I] (1) and [CuL(PPh3)2]BF4 (2). While solid state emission of L is due to the ligand-centerd π → π* transition, luminescence of 1 and 2 was assigned to a (M + X)LCT and MLCT excited states, respectively.