Alkynyl derivatives of gold complexes containing C6H3-5-Me-2-EPh2 (E = P, As) ligands

Au₂Cl₂{μ-2,2′-Ph₂As(5,5′-Me₂C₆H₃C₆H₃)AsPh₂}] reacts with phenylacetylene or ethynylferrocene to give the corresponding digold(I) bis(alkynyl) derivatives Au₂(CCR)₂{μ-2,2′-Ph₂As(5,5′-Me₂C₆H₃C₆H₃)AsPh₂}] R = Ph (4), Fc (5)]. In contrast, products resulting from the reaction with 1,3- or 1,4-diethynylbenzene (deb) depend markedly on the dichlorodigold(I) complex to ligand ratio. When an excess of alkyne is used, the expected bis(alkynyl) complexes Au₂X₂{μ-2,2′-Ph₂As(5,5′-Me₂C₆H₃C₆H₃)AsPh₂}] X = 1,3-deb (6), 1,4-deb (7)] are obtained, but when using a 1:1 molar ratio poorly soluble, presumably polymeric, species are formed. Attempts to prepare a digold(II) bis(alkynyl) derivative by treatment of Au₂Cl₂(μ-C₆H₃-5-Me-2-PPh₂)₂] with ethynylferrocene in the presence of NaOMe gives a mixture of species, the recrystallization of which yielded a crystal of {2-(FcCC)-4-MeC₆H₃PPh₂}Au(CCFc)] (1). The reaction of Au₂Cl₂(μ-C₆H₃-5-Me-2-AsPh₂)₂] with phenylacetylene, 1,3- or 1,4-deb gives a mixture of unidentified products.