Epoxidation of olefins catalyzed by manganese(II) complexes of Schiff base ligand having N2O coordination

Three mononuclear manganese(II) complexes having two N2O coordination spheres have been examined as catalysts for epoxidation of (E)-stilbene and styrene using Phi and NaOCl as terminal oxidants in four different solvents. The catalytic efficiency of the complexes are observed to be influenced not only by their own structural features but also by the nature of terminal oxidant, substrate as well as the solvents. Epoxidation proceeds with the formation of two different intermediates, O=Mn(IV)(L)(X) and Cl-O-Mn(II)(L)(X) [X=NO3/SCN/N(CN)(2)], in presence of PhIO and NaOCl respectively. Amongst the solvents, acetonitrile is found to be the most suitable.