Metallo Porphyrins are widely used in catalysis. In the present study ab initio calculations have been used to study the epoxidation of ethylene by a manganese porphyrin.
Gas phase calculations on a simplified manganese porphyrin molecule were performed to determine the charge distribution, multiplicity and geometry of the ground state.
Hartree-Fock calculations predict that the first intermediate ( manganese-oxo-chloro-porphyrin) has the oxygen-forming a bridge between the manganese and one of the nitrogen atoms.
Further calculations demonstrate that the ethene molecule approaches the manganese-oxo-chloro-porphyrin intermediate perpendicular to the oxygen-nitrogen bridge resulting in the formation of an Manganese(III)-epoxide-chloro-porphyrin intermediate.