Selective Oxygenation of Olefins with Hydrogen Peroxide Catalyzed by Iron(II) Bipyridine Included in NaY Zeolite under Visible Light Irradiation

A novel visible light photocatalyst of iron(II) bipyridine complex encapsulated within NaY zeolite for selective oxygenation of styrene with high turnover (1800) and high benzaldehyde selectivity (86%) using hydrogen peroxide as the oxidant under ambient conditions was explored. This photocatalyst was also effective for the oxidation of other olefins, such as 4-cyanostyrene, 4-methoxystyrene, 3-methylstyrene, 1,1-diphenylethylene, cis-stilbene, trans-stilbene, trans--methylstyrene, -methylstyrene, triph- enylethylene, 1-octene, 2-octene, cyclohexene and cyclooctene, into the corresponding aldehydes, ketones or olefin oxides. The study shows that the photooxygenation of styrene occurs within the supercages of zeolite Y, the products benzaldehyde and formaldehyde escape into the solution after reaction, leading to high turnovers. Based on the experimental results, the photooxidation mechanism is also discussed.