UC Davis

Five new crystalline gold(I) complexes β-Au2(μ-dppm)2Br2·2CH2Cl2 (1), [Au2(μ- dppm)2Br]Br·2CH2Cl2 (2), [Au2(μ-dppm)2Br](PF6) (3), [Au2(μ-dppm)2Cl](BPh4)·3CH2Cl2 (4) and [Au2(μ-dppm)2]Cl(AsF6)·2CH2Cl2 (5) (where dppm is bis(diphenylphosphino)methane) have been prepared and structurally characterized by single crystal X-ray diffraction. Colorless β-Au2(μ-dppm)2Br2·2CH2Cl2 (1) has centrosymmetric structure with two three-coordinate gold(I) ions held in close proximity by the dppm ligands. Crystals of [Au2(μ- dppm)2Br]Br·2CH2Cl2 (2), [Au2(μ-dppm)2Br](PF6) (3), and [Au2(μ-dppm)2Cl](BPh4)·3CH2Cl2 (4) have a cation with an unusual arrangement that binds a two-coordinate gold(I) ion to a three-coordinate gold(I) ion through an aurophilic interaction. Whereas Au2(μ-dppm)2Cl(BPh4)·3CH2Cl2 (4) has a chloride ion bound to only one of the gold ions in the complex, [Au2(μ-dppm)2]Cl(AsF6)·2CH2Cl2 (5) has an ion paired chloride ion that is symmetrically disposed between the two gold ions at a rather long distance. Each complex displays luminescence under UV irradiation.