Ab initio calculation on oxomanganese porphine chloride; relevance to its oxidizing capacity†

The minimal basis-set gradient-SCF calculations on the title molecule are reported with a view to elucidating its electronic structure and contributing towards a better understanding of its catalytic capacity in epoxidation reactions. It has been found, within C4v symmetry, that the oxygen is predominantly π-bonded to the metal atom in a closed-shell spin state of the complex. The availability of low-lying unoccupied Mn d π-O pπ molecular orbitals provides a plausible explanation for the oxygen insertion in epoxidation reactions.