Synthesis and design of novel tetranuclear and dinuclear gold(I) phosphine acetylide complexes. First X-ray crystal structures of a tetranuclear ([Au-4(tppb)(C CPh)(4)]) and a related dinuclear ([Au-2(dppb)(C CPh)(2)]) complex

Reaction of [Au(C=CR)](infinity) with dppb and tppb in CH2Cl2 afforded the corresponding luminescent Au-2(dppb)(C=CR)(2) and Au-4(tppb)(C=CR)(4) (dppb = 1,4-bis(diphenylphosphino)benzene; tppb = 1,2,4, 5-tetrakis(diphenylphosphino)benzene; R = C6H13, Ph, 4-MeO-Ph); their photophysical properties have been studied, and the X-ray crystal structures of Au-2(dppb)(C=CP)(2) (2) and Au-4(tppb)(C=CPh)(4) (5) have been determined. Close Au ... Au contacts are present in 5, which twisted the six-membered ring that comprises the PAu2PC2 unit. Such a structure is reminiscent of a distorted anthracene-like unit containing Au atoms as part of the heterocycle, owing to the auriophilicity which brings the Au atoms into close contact.