Bb. De et al., SYNTHESIS OF CATALYTICALLY ACTIVE POLYMER-BOUND TRANSITION-METAL COMPLEXES FOR SELECTIVE EPOXIDATION OF OLEFINS, Macromolecules, 27(6), 1994, pp. 1291-1296
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.