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(Ctriple bond; length of mdashCR)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-(FcCtriple bond; length of mdashC)-4-MeC6H3PPh2}Au(Ctriple bond; length of mdashCFc)] (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.