Neutral and Cationic Gold(I) Complexes with π-Conjugated Phosphasilene Ligands

A series of neutral and cationic Au(I) complexes incorporating π-conjugated phosphasilene ligands stabilized by the bulky 1,1,3,3,5,5,7,7-octa-R-substituted s-hydrindacen-4-yl (Rind) groups have been synthesized. X-ray crystallographic studies show the η1-coordination mode of the phosphasilene ligand, accommodating the linear trans two-coordinate geometry around the gold center. While the metal coordination slightly enhances the intensity of the strong π–π* absorption of the phosphasilene chromophores, the phosphashilene π-conjugation is not extended through the Au atom.