Metal–acetylene complexes. II. Acetylene complexes of nickel, palladium, and platinum

The preparations of complexes of the type L 2 M(RC 2 R′) (where L = Ph 3 P, M = Ni, Pd, Pt, R = R′ = CF 3 ; L = Ph 3 P, M = Ni, Pt, R = R′ = Ph, and R = Ph, R′ = Me; L = Ph 3 P, M = Pd, Pt, R = R′ = COOMe; and R = R′ = CF 3 , M = Pd, Pt, L = n-Bu 3 P, Mc 2 PhP) are described. From their nuclear magnetic resonance spectra these complexes appear to be approximately planar in solution. The V C≡C observed in their infrared spectra indicate strong bonding of the acetylene to the metal.A new approach to the bonding in metal–acetylene complexes is proposed which can be extended to other π-complexes and which allows some predictions to be made.