ZEOLITE-ENCAPSULATED MN(II) COMPLEXES AS CATALYSTS FOR SELECTIVE ALKENE OXIDATION

COMPLEXES of manganese(II) with bipyridine (bpy) have the potential to act as catalysts for oxidation of alkanes and alkenes when the comple x is oxidized in acidic conditions(1-6). But their catalytic activity in solution is limited by their catalase activity(7)-their tendency to decompose H2O2. Because of their polynuclear nature such complexes ca nnot induce epoxidation of alkenes, and other epoxidation catalysts su ffer from self-oxidation and side reactions(8-11). Moreover, all of th ese homogeneous catalytic processes require phase-transfer conditions. Here we report that, when encapsulated in the supercages of zeolites X and Y, cis-[Mn(bpy)(2)](2+) complexes can catalyse selective epoxida tion of alkenes without complications from competing processes such as self-oxidation or catalase activity. Epoxidation of cycloalkenes is f ollowed by acid-catalysed ring-opening, carbon-carbon bond cleavage an d formation of alkenedioic acids (Fig. 1). All of the various intermed iates in the process can be obtained selectively by controlling the re action conditions and zeolite acidity. Thus this supramolecular system provides a clean, one-step heterogeneous catalytic route to useful in dustrial products.