Reactivity of an Acetylenephosphino Gold(III) Precursor:  Addition to the Triple Bond or Formation of Alkynyl Derivatives

We have synthesized the gold(III) complex Au(C₆F₅)₃(PPh₂CCH) (1), containing an acetylene moiety. Reactions with sodium alkoxides lead chemoselectively and regioselectively to gold(III) complexes containing the new ligand (2-alkoxyethenyl)diphenylphosphine or (2,2-dialkoxyethyl)diphenylphosphine, via a single or double alcohol addition to the acetylenephosphine fragment. Reaction of complex 1 with gold(I) or silver(I) acetylacetonato derivatives affords di-, tri-, or tetranuclear alkynylphosphino complexes, namely Au^III(C₆F₅)₃(PPh₂CC)M^I(PPh₃) (M = Au, Ag), {Au^III(C₆F₅)₃(PPh₂CC)}₂Au^I, and {Au^III(C₆F₅)₃(PPh₂CC)Au^I}₂(μ-PPh₂CH₂CH₂PPh₂). The crystal structures of Au(C₆F₅)₃(PPh₂CH₂CH(OMe)₂) and Au^III(C₆F₅)₃(PPh₂CC)Au^I(PPh₃) have been determined by X-ray diffraction studies. Luminescence studies in the solid state show that only the tetranuclear derivative is luminescent at room temperature.