Theoretical Study of the Pseudo-Jahn−Teller Effect in the Edge-Sharing Bioctahedral Complex Mo2(DXylF)2(O2CCH3)2(μ2-O)2

Abstract

A study of the D(2h) to C(2h) pseudo-Jahn-Teller distortion in the edge-sharing bioctahedral complex Mo(2)(DXylF)(2)(O(2)CCH(3))(2)(mu(2)-O)(2) is presented. We have performed extensive density functional theory (DFT) and complete active space self-consistent field (CASSCF) calculations. For both the full target complex and a model derived by replacing xylyl and methyl groups with hydrogens we observe that the central Mo(2)(mu(2)-O)(2) motif displays C(2h) rather than D(2h) symmetry. Analytical CASSCF frequency calculations prove that the rhomboidal distortion of the complex from D(2h) to C(2h) is due to a vibronic mixing of the ground electronic state and a low-lying pidelta* excited state.