Synthesis Of Chiral Salen Mn(Ⅲ) Complexes Supported On Aminated ZSPP By A Axial Methord And Their Catalytic Asymmetric Epoxidation Of Olefins

Zirconium oligo-chloromethyl-polystyrenylphosphonate-phosphate(ZSPP) is a new type of organic-inorganic hybrids material developed by our group. This kind of organic-inorganic hybrid heterogeneous catalysts shows high thermal stability, good catalytic activities and excellent reusability as solid acid catalysts.Chiral Salen Mn(III) complex axially immobilized on modified ZSPP was prepared by covalent grafting and its catalytic activities on epoxidation of unfunctional olefins were investigated.In this work, we are pursuing our studies in this untapped area and aminomethyl-zirconium oligo-styrenyl phosphonate hydrogen phosphate was prepared by the reaction of ZCMSPP with diamines and then homogeneous chiral Salen Mn(III) was grafted onto modified ZSPP by a axial coordination immobilize mode, so a new type of heterogeneous chiral Salen Mn(III) catalysts was obtained. All the supported heterogeneous chiral Salen Mn(III) complexes prepared were characterized by FT-IR, diffusion reflection UV-Vis, AAS, N₂ volumetric adsorption, SEM, TEM and TG. The NaClO and m-CPBA were used as oxidant for asymmetric epoxidation of styrene,α-methylstyrene and indene respectively. The factors, such as amount of catalyt, co-catalyst, the reaction time, the reaction temperature and axial length were investigated for asymmetric epoxidation of styrene. These supported chiral catalysts showed a little lower chiral induction (ee, 72%) and conversion (Yield, 56%) for asymmetric epoxidation of styrene in presence of NMO as axial ligands with m-CPB A as oxidant. The catalysts were easily recovered by filtration and could be reused at least five times with little loss of activity and enantioselectivity.