Preparation, Characterization And Catalysis Of Chiral Iridium, Ruthenium And Rhodium Catalysts Supported On Bifunctional Mesoporous Silicon Materials

Imidazolium-Based organic-inorganic hybrid silica (1BOIHS) has the advantageof simple preparation，easy modification. As a compound having a double supportfeatures, which itself has the role of phase transfer catalysis in the catalytic reaction,having a more favorable effect in heterogeneous catalytic reactions involved as well.In addition, the material also has high thermodynamic stability，while a large numberof surface hydroxyl groups，a catalyst to facilitate the modification andimmobilization. Hydroxy and mostly located in the surface of the material，the moreextensive and uniform distribution of active sites on these characteristics of theprepared solid catalyst carrier, a material having an open lamellar microstructureconducive substrates to the catalytically active centers, while the product is alsobeneficial to enhance stereoselectivity. Periodic mesoporous organosilica (PMO) has alarger surface area and pore volume, pore size and arranged in an orderly andcontrollable pore size distribution, high thermodynamic and mechanical stability,PMO material has its specific properties such as has high hydrophobicity, theysignificantly promote the conversion of the organic functional group in the innersurface of the silica. Advantages of these two materials based on various aspects, wedesigned and synthesized two types of supported catalysts and explored theirrespective catalytic properties.(1) Preparation and catalytic properties of rhodium imidazolium-Basedorganic-inorganic hybrid silica as a carrier immobilized chiral precursor three kinds ofheterogeneous catalysts (Cp*IrTsDPEN, Cp*RhTsDACH and ArRuTsDPEN) to givethree kinds of homogeneous catalysts and they exhibit higher catalytic activity andenantioselectivity. Systematic study of the catalyst for catalyzing the aromatic ketoneand the like, one asymmetric hydrogen transfer reactions in the aqueous phase in thecatalytic activity and stereoselectivity which has equal performance with a homogeneous catalyst or even better, more importantly, heterogeneous catalysts3caneasily be recycled and catalyze asymmetric hydrogen transfer acetophenone10timesby centrifugation and remain good catalytic activity and stereoselectivity.Demonstrate its broad prospects and potential applications in catalysis synthesis.(2) Synthesis of a Periodic mesoporous organosilica PMO (1) as a carirer immobilizedchiral precursors S/Olefin-Rh catalyst to obtain a heterogeneous catalystS/Olefin-Rh-PMO (3)，showing a homogeneous catalyst with relatively high catalyticactivity and enantioselectivity. And by characterizing proved homogeneous catalystsS/Olefin-Rh has been successfully immobilized on mesoporous PMO silica (1). Moreimportantly, the more important is the heterogeneous catalyst S/Olefin-Rh-PMO (3) in1,4-addition reactions can be easily recovered by centrifugation and re-use of theheterogeneous catalyst was repeated eight times more practical, but also exhibitsexcellent activity and enantioselectivity, showing its broad prospects in the catalyticsynthesis and potential applications.