摘要:
The mixed ligand complexes Cr-III(dpa)(L)Cl and Fe-III(dpa)(L)(H2O)(x)Cl (where dpa = dipicolinic acid, L = ethylenediamine, 2,2-bipyridine or 1,10-phenanthroline, n = 1 or 2) were synthesized and characterized by elemental analysis and spectral, magnetic, conductance and electrochemical studies. The complexes were evaluated for their activity as catalysts for the epoxidation of olefins. The chromium complexes catalyzed epoxidation of olefins, viz., norbornene, cis-cyclooctene, styrene and cyclohexene with iodosylbenzene, to give corresponding epoxides. Oxidation of cyclohexene gave allylic oxidation products besides the epoxide. The iron complexes were nearly inactive as epoxidation catalysts under these conditions. Spectrophotometric and electrochemical measurements were used to deduce the cause of low catalytic activity.