Spectroscopic and Electrochemical Studies of Group 6 and 8 Transition Metal Carbonyl Derivatives of tris{(diphenylphosphinomethyl)dimethylsilyl}methane

Abstract

A new series of transition metal carbonyl complexes of tris{(diphenylphosphinomethyl)dimethylsilyl}methane are described in this work. Treatment of M(CO) 6 (M = Cr, W, Mo) and Fe 2 (CO) 9 with [(Ph 2 PCH 2 Me 2 Si) 3 CH] in tetrahydrofuran at elevated temperature resulted in the isolation of [M(CO) 3 {(Ph 2 PCH 2 Me 2 Si) 3 CH}] (M = Cr(1), Mo(2), W(3), Fe(4)) in good yield. These complexes have been characterized by elemental analysis, conductivity measurements, mass spectrometry, with IR, electronic, 1 H and 31 P NMR spectroscopy, and cyclic voltammetry. The data suggest that complexes 1, 2, 3, and 4 have octahedral geometry around the metal atom with tridentate coordination of the ligand. Electrochemical studies of 1, 2, 3, and 4 using cyclic voltammetry indicate quasireversible metal centered oxidation (E •/ −1.217 V(1), −1.218 V(2), −1.166 V(3), and −1.258 V(4) versus Ag/Ag + ) and ligand reductions (0.292 V, 0.170 V, −0.331 V, and 0.338 V versus Ag/Ag + ).