Synthesis and design of novel tetranuclear and dinuclear gold(I) phosphine acetylide complexes. First X-ray crystal structures of a tetranuclear ([Au4(tppb)(C≡CPh)4]) and a related dinuclear ([Au2(dppb)(C≡CPh)2]) complex

Abstract

Reaction of [Au(C≡CR)]∞ with dppb and tppb in CH2Cl2 afforded the corresponding luminescent Au2(dppb)(C≡CR)2 and Au4(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 Au2(dppb)(C≡CPh)2 (2) and Au4(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.