Interaction of Gold Acetylides with Gold(I) or Silver(I) Cations

Structures and properties of complexes between (trimethylphosphino)gold acetylides and another (trimethylphosphino)gold cation have been studied in the light of the possible "dual activation" reaction mode in gold catalysis. Silver salts are often used as cocatalysts in gold catalysis; therefore, also mixed complexes of acetylides with (trimethylphosphino)gold(I) and silver(I) cations have been investigated. Energy-resolved collision-induced dissociation experiments, ion spectroscopy, and density functional theory calculations show that the gold and silver cations preferentially coordinate to the gold acetylides rather than to neutral CC triple bonds in diyne-type substrates. The effect of the binding of two metal cations to acetylides with respect to nucleophilic additions is discussed.