Structural and Electronic Features of o-Phenylenediamido Complexes of Group 6 Metals in Different Oxidation States

Reported complexes of general formula L 4 M(phenylenediamido-o), where M is a metal of group 6 in various oxidation states (VI, IV, II and 0), are analyzed. The possible structural deviations from the most symmetric pseudo-octahedral structure (the one with the chelate in the equatorial plane) are evaluated, case by case, in view of their electronic origin. The analysis is based on systematic DFT calculations and their qualitative MO interpretation based on perturbation theory concepts.