Synthesis, Characterization, and Reactivity of Cationic Gold(I) α-Diimine Complexes

A series of cationic gold(I) α-diimine complexes of the type [(NHC)Au(α-diimine)]X or [(PPh3)Au(α-diimine)]X, where NHC = IPr, α-diimine = BIAN-dipp, X = PF6 (1); X = BF4 (2); X = SbF6 (3); NHC = ItBu, α-diimine = BIAN-dipp, X = PF6 (4); X = BF4 (5); NHC = IMes, α-diimine = BIAN-dipp, X = PF6 (6); PPh3, α-diimine = BIAN-dipp, X = PF6 (7); NHC = IPr, α-diimine = DAB-Mes, X = PF6 (8, 10) bearing an N-heterocyclic carbene (NHC) or a phosphine ligand, have been synthesized and characterized by NMR spectroscopy and single crystal X-ray diffraction. The stability of the new complexes and their catalytic activity for the intermolecular addition of the indole nucleophilic carbon to 1,6-enyne were also investigated.