Selective oxidation of olefins within organic dye cation-exchanged zeolites

Abstract

This paper reports selectivity in the products during single oxygen mediated oxidation of olefins included within dye-exchanged X and Y zeolites. Singlet oxygen is generated within a zeolite by irradiating a thiazine dye exchanged into zeolites. Oxazine and thiazine dye molecules can be readily exchanged for alkali cations present in the interior of faujasite (X and Y) zeolites. Depending on the status of hydration, these dye molecules exist either in monomeric or dimeric forms. We show here that when a thiazine dye molecule is present in its monomeric form within a zeolite, it serves as an excellent singlet oxygen sensitizer. Utilizing zeolite supercages as `active reaction cavities`, we have directed the reactive oxygen toward a particular face of the olefin and obtained a high selectivity in the products of oxidation.