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

The syntheses and solution characterizations of [Ir(ppy)(2)(1)[PF6] (1 =4,4`-di(2-furany1)-6,6`-dimethy12,2`-bipyridine), [Ir(ppy)(2)(dppe)1[PF6] (dppe =1,2-bis(diphenylphosphino)ethane), [Ir(ppy)(2)(2)][PF6] (2 =1,2-bis(diphenylphosphino)benzene) and [Ir(PPY)2(3)1[PF6] (3 = 2-diphenylphosphinothioanisole) are reported. Solutions of the iridium(Ill) 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]center dot 2CH(2)Cl(2). [Ir-(ppy)(2)(dppe)][PF6]. 4[1r(ppy)(2)(2][PF6]center dot 3CH(2)Cl(2) and [Ir(ppy)(2)(3)][PF6] have been determined, and the role of inter-ligand face-to-face It-stacking (a means of suppressing emission quenching) in the [Ir(ppy)(2)(ppy)(2)(dppe)](+), [Ir(ppy)(2)(2)](+) and [Ir(ppy)(2)(3)](+) cations is assessed.