DFT studies on the reaction pathway of the catalytic olefin epoxidation with CpMoCF3 dioxo and oxo-peroxo complexes

A comparative gas-phase density functional theory (DFT) study of the catalytic epoxidation of olefins with the possible intermediates [CpMoVI(CF3)(O)(2)] and CpMoVI(CF3)(OO)(O) is presented. The main focus is the identification of the catalytic active species and relevant transition states. Apparently the peroxo-oxo compound is catalytically more active. The influence of the oxidant, tert-butyl hydroperoxide (TBHP), is also considered. The most likely intermediates (postulated by an experimental study) are compared with respect to their occurrence at the potential energy surface and thus the most feasible pathways for the epoxidation of ethene with an excess of TBHP under Mo-O catalysis are examined. (C) 2013 Elsevier B.V. All rights reserved.