Photophysical properties and crystal structures of luminescent phenylethynylgold(I) complexes of alkyl and aryl isocyanides

Abstract

Several phenylethynylgold(I) complexes were prepared by treating [{Au(CC–Ph)}_∞] with 2,5-diisocyano-2,5-dimethylhexane (L¹), (1,8-diisocyano-p-menthane (L²) and 2,6-dimethylphenyl isocyanide in dichloromethane. The intermolecular Au ⋯ Au separations established by X-ray crystal analyses are 3.329(4), 3.565(2) and 3.485(3)Å for the crystals of [(Au(CCPh)(CNC₆H₃Me₂-2,6)], [{Au(CCPh)}₂L¹] and [{Au(CCPh)}₂L²] respectively. These gold(I) complexes have long-lived and emissive ³(ππ*) excited states in fluid solutions at room temperature. The photoredox properties of [Au(CCPh)(CNC₆H₃Me₂-2,6)] have been studied by Stern–Volmer quenching experiments, and its excited-state redox potential E°(Au⁺–Au⁰*) is –1.62(1) V vs. saturated sodium chloride calomel electrode.