Nature of M–Ge Bonds in the Metallogermylene Complexes of Chromium, Molybdenum, and Tungsten [(η5-C5H5)(CO)3M{GeN(SiMe3)R}] and [(η5-C5H5)(CO)3M{GeN(Ph)R}] (R = Ph, Mesityl (Mes)): A Theoretical Study

Abstract

Geometry and bond energy analysis of M–Ge bonds in the terminal metallogermylenes of chromium, molybdenum, and tungsten [(η5-C5H5)(CO)3M{GeN(SiMe3)R}] and [(η5-C5H5)(CO)3M{GeN(Ph)R}] (R = Ph, mesityl (Mes)) were investigated by DFT methods (BP86, PBE, and PW91) and the DFT-D3_BJ level of theory. The calculated geometric parameters of the molybdenum–aminogermylene complexes are in excellent agreement with the available experimental values. The M–Ge bonds in these complexes are essentially M–Ge single bonds. The optimized Ge–N bond distances are slightly smaller than those expected for a single bond on the basis of covalent radii predictions. The bent coordination geometries at germanium (M–Ge–N bond angles in the range 115.3–118.5°) in these complexes are consistent with the presence of a divalent Ge(II) atom, which is singly bonded to a transition metal and the nitrogen of the NRR′ groups. In all studied complexes, the π-bonding contributions to the total M–Ge bonds are significantly smaller (∼17–18%) tha...