Group 6 metal carbonyl complexes of a family of bulky phosphines: spectroscopic and structural studies of chromium(0)-,molybdenum(0)- and tungsten(0)-pentacarbonylsilylphosphines

Abstract

The synthesis and spectroscopic data of six Group 6 metal complexes with the silylphosphine ligands, P(C₆H₅){Si(CH₃)₃}₂ and P(H){Si(CH₃)₃}₂ are reported. The crystal structures of M(P{R}{TMS}₂)(CO)₅, M = Cr, Mo, W; R = C₆H₅ and M = Cr; R = H, are reported. All the compounds exhibit the expected structures consisting of an octahedral geometry of five carbonyl ligands and one silylphosphine ligand around the metal center. Analysis of the spectroscopic and structural data, including the previously reported P{Si(CH₃)₃}₃ ligand, indicate the steric bulk of the ligands decreases and the sigma-donating ability increases in the series P{Si(CH₃)₃}₃ < P(C₆H₅){Si(CH₃)₃}₂ < P(H){Si(CH₃)₃}₂.