Dispersion, solvent and metal effects in the binding of gold cations to alkynyl ligands: implications for Au(I) catalysis

The coordination modes of the [Au(PPh3)]+ cation to metal alkynyl complexes have been investigated. On addition to ruthenium, a vinylidene complex, [Ru([small eta]5-C5H5)(PPh3)2([double bond, length as m-dash]C[double bond, length as m-dash]CPh{AuPPh3})]+, is obtained while addition to a gold(iii) compound gives di- and trinuclear gold complexes depending on the conditions employed. In the trinuclear species, a gold(i) cation is sandwiched between two gold(iii) alkynyl complexes, suggesting that coordination of multiple C-C triple bonds to gold is facile.