Theoretical Study of the Distortion from Regular Tetrahedral Structure of M(NH2)4 Complexes

Abstract

Theoretical study on tetrakis-amido complexes (M(NR2)4, M = Ti, V, Cr, and Mo; R = H, Me) is presented. At first a rough investigation of the potential energy surface indicates that all stationary points are of S4 or D2 symmetry depending on the coupled rotations of the NR2 groups. Qualitative correlation diagrams are calculated within S4 or D2 symmetry constraint between two limiting structures of D2d symmetry. DFT (B3LYP) calculations on these two paths are presented for unsubstituted complexes (R = H) and the various minima are optimized and characterized. These results are discussed in the light of the correlation diagrams. Finally, optimization of the different minima has been performed on substituted species (R = Me) and the theoretical results are shown to be in good agreement with the experimental structural determination when available.