SYNTHESIS OF CATALYTICALLY ACTIVE POLYMER-BOUND TRANSITION-METAL COMPLEXES FOR SELECTIVE EPOXIDATION OF OLEFINS

Catalytically active metal-complexing polymers containing Mn(III) moie ties were synthesized for use in the selective epoxidation of olefins. For this purpose two different monomers, 1b and 2b, bearing the Mn(II I)-Salen moiety (known to be a good candidate for catalyzing olefin ep oxidation) were synthesized and subsequently copolymerized with ethyle ne glycol dimethacrylate, producing insoluble cross-linked polymer net works possessing a macroporous morphology. Metal-containing polymers w ere also obtained by chemical modification of cross-linked polymers be aring the Salen units (obtained by polymerizing 1a and 2a). The cataly tic activities of all these polymers were evaluated during epoxidation of olefins. The polymers were able to catalyze the epoxidation of a v ariety of olefins at room temperature in the presence of iodosylbenzen e (PhIO) as the terminal oxidant. The rates of epoxidations using thes e polymeric catalysts were relatively slow compared to that of the cor responding homogeneous system. However, the epoxidation reactions were selective with predominant formation of the desired epoxides over oth er side oxidation products. No significant influence of the spacer len gth between the polymer backbone and metal-complexing sites on the rat e of epoxidation was observed.