Softening the donor set for light-emitting electrochemical cells: [Ir(ppy)2(N^N)]+, [Ir(ppy)2(P^P)]+ and [Ir(ppy)2(P^S)]+ salts

The syntheses and solution characterizations of [Ir(ppy)2(1)][PF6] (1 = 4,4′-di(2-furanyl)-6,6′-dimethyl-2,2′-bipyridine), [Ir(ppy)2(dppe)][PF6] (dppe = 1,2-bis(diphenylphosphino)ethane), [Ir(ppy)2(2)][PF6] (2 = 1,2-bis(diphenylphosphino)benzene) and [Ir(ppy)2(3)][PF6] (3 = 2-diphenylphosphinothioanisole) are reported. Solutions of the iridium(III) complexes incorporating 1, 2 and dppe are photoluminescent, but [Ir(ppy)2(3)][PF6] is non-emissive. The single crystal structures of [Ir(ppy)2(1)][PF6]·2CH2Cl2, [Ir(ppy)2(dppe)][PF6], 4[Ir(ppy)2(2)][PF6]·3CH2Cl2 and [Ir(ppy)2(3)][PF6] have been determined, and the role of inter-ligand face-to-face π-stacking (a means of suppressing emission quenching) in the [Ir(ppy)2(dppe)]+, [Ir(ppy)2(2)]+ and [Ir(ppy)2(3)]+ cations is assessed.

Graphical abstractThe syntheses, solution characterization and solid state structures of four [Ir(ppy)2L][PF6] complexes in which L is a chelating N^N, P^P or P^S are reported. The role of inter-ligand face-to-face π-stacking in the complexes containing P^P or P^S ligands is discussed.Figure optionsDownload full-size imageDownload as PowerPoint slide