Olefin Epoxidation catalysed by Manganese(III) Schiff Base Complexes : Evidence of Oxomanganese(IV) Formation

School of Studies in Chemistry, Jiwaji University Gwalior-474 011 Manuscript received 5 May 1994, accepted 4 April 1995 Expoxidation of cyclohexene shows that ligands with N4 system are better catalyst. Epoxide yield decreases with increase in catalyst concentration. Competitive epoxidation of cyloolefins using 0.001 mmol catalyst shows that breaking of olefin-catalyst complex is the rate-determining step, while 0.01 mmol catalyst suggests that formation of oxomanganese is the rate-determining step. cis-Stilbene gave a mixture of cis- and trans-epoxides. Norbornene gave only exo-epoxide. Nonionic surfactant catalyses the norbornene epoxidation and pyridine addition improves the yield. Epr, ir and cyclic voltammetry support the formation of oxomanganese(IV) species as one of the oxidising species