Synthesis, structural characterization, and luminescence studies of gold(I) and gold(III) complexes with a triphosphine ligand

We have synthesized a series of trinuclear and tetranuclear gold(I) complexes [(mu-dpmp)(AuX)(3)] (dpmp = bis(diphenylphosphinomethyl)phenylphosphine X = Cl (1), C6F5 (2)), [Au-3(mu-dpmp)(2)] (CF3SO3)(3) (3), and [Au-4(mu-dpmp)(2)Cl-2](CF3SO3)(2) (4). Complex 4 displays a rhomboidal geometry for the gold atoms with short gold-gold distances of 3.1025(11) and 3.1059(14) Angstrom. We have also prepared the mononuclear and dinuclear gold(III) complexes [(mu-dpmp){Au(C6F5)(3)}(n)] (n = 1 (5), 2 (6)). The crystal structure of 5 has been determined by X-ray diffraction studies, which show that gold is coordinated to the central phosphorus although two isomers are observed in solution. Treatment of 6 with gold(I) derivatives affords trinuclear mixed-valence gold(I)-gold(III) [(mu-dpmp)-{Au(C6F5)(3)}(2)(AuX)] (X = Cl (7), C6F5 (8)). The luminescent properties of these complexes in the solid state have been studied. Likewise, it has been found that the gold(I) complexes are luminescent but not so the gold(III) or mixed-valence complexes.