Ruthenium complexes are good epoxidation catalysts, 4 which form high valent oxo-ruthenium species as active intermediates in the oxygen transfer process. Ruthenium complexes with nitrogen based ligands 5 have been extensively studied in recent years to develop new catalysts with better selectivity and several co-oxidants have been employed to get the best results. Clearly, the ideal oxidant would be molecular oxygen since it is least expensive and also ...