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 Fe2(CO)9 with [(Ph2PCH2Me2Si)3CH] in tetrahydrofuran at elevated temperature resulted in the isolation of [M(CO)3{(Ph2PCH2Me2Si)3CH}] (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, 1H and 31P 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+).