Synthesis and catalytic property of poly(styrene- co-divinylbenzene) supported ruthenium(III)-2-aminopyridyl complexes

Abstract

Chloromethylated styrene-divinylbenzene copolymer beads with 8 and 14% cross-link were chemically modified by a reaction with 2-aminopyridine leading to the incorporation of nitrogen ligating sites on the surface of the polymer. These polymeric ligands, on treatment with a solution of ruthenium(III) chloride, gave the corresponding metal complex. The polymer supported Ru(III) complexes were characterized by elemental analysis, FT-IR, diffuse reflectance, SEM and DTA-TGA methods. The epoxidation of cis-cyclooctene, cyclohexene and styrene was investigated using the supported metal catalysts in presence of tert-butyl hydroperoxide as the terminal oxidant. Cis-cyclooctene gave the corresponding epoxide in a maximum yield of 51% whereas in case of styrene both styrene oxide and secondary oxidation product benzaldehyde were obtained in a combined yield of 95% under similar conditions. Surprisingly with cyclohexene as substrate the major product was 2-cyclohexene-1-one (64%) compared to the epoxide (2 %).