Synthesis of two new Mo(II) organometallic catalysts immobilized on POSS for application in olefin oxidation reactions

Abstract

The purpose of this work was the preparation and characterization of two new catalysts POSS-ATZAc-[Mo(η3-C3H5)Br(CO)2] (POSS-Mo-I) and POSS-ATZAc-[Mo(CO)3Br2] (POSS-Mo-II). The new heterogeneous catalysts were characterized by several techniques and used as catalysts for the epoxidation of olefins, presenting high catalytic activity. To study and optimize the syntheses of the heterogeneous catalysts, immobilization experiments of the [Mo(η3-C3H5)Br(CO)2(NCMe)2] and [Mo(CO)3Br2(NCMe)2] organometallic complexes on the modified polyhedral oligomeric silsesquioxane were performed. The sorption properties of the modified silsesquioxane showed to be dependent of the contact time, concentration and temperature. Catalysts were tested in the epoxidation of six olefins and compared with homogeneous species [Mo(η3-C3H5)Br(CO)2(ATZAc)] (Mo-I) and [Mo(CO)3Br2(ATZAc)] (Mo-II). To the best of our knowledge, this paper is the first that has reported the preparation and characterization of two new heterogeneous catalysts, as well as the comparison with homogeneous species for catalytic epoxidation of olefins.