Readily accessible mesoporous silica nanoparticles supported chiral urea-amine bifunctional catalysts for enantioselective reactions |
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Authors: | Yaşar Gök İrem Tutkum Aykut Halil Zeki Gök |
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Affiliation: | 1. Department of Biomedical Engineering, Bucak Faculty of Technology, Burdur Mehmet Akif Ersoy University, Burdur, Turkey;2. Department of Biomedical Engineering, Bucak Faculty of Technology, Burdur Mehmet Akif Ersoy University, Burdur, Turkey Contribution: Investigation, Methodology |
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Abstract: | The main objective of this study is to develop readily accessible and recyclable solid catalysts for enantioselective reactions. To achieve this, magnetic MCM-41 and non-magnetic SBA-15 mesoporous supports were prepared, then mesoporous silica supported chiral urea-amine bifunctional catalysts were synthesized by grafting of chiral urea-amine ligand onto SBA-15 and magnetic MCM-41. The magnetic and non-magnetic supports and so-prepared solid catalysts were characterized by using different methods such as N2 sorption measurements, Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscope-energy dispersive X-ray analysis (FESEM-EDX), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). Results showed that (1R, 2R) or (1S, 2S)-1,2-diphenylethane-1,2-diamine was successively immobilized onto magnetic MCM-41 and SBA-15 pores. The heterogeneous chiral solid catalysts and their homogenous counterparts exhibited high activities both enantioselective transfer hydrogenation reaction (up to 99% conversion and 65% ee) and enantioselective Michael reaction (up to 98% conversion and 26% ee). Moreover, the SBA-15 supported solid catalysts were separated from the reaction mixture by simple filtration, whereas the magnetic MCM-41 supported solid catalysts were separated by simple magnetic decantation and reused in three consecutive catalytic experiments. |
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Keywords: | chirality enantioselectivity heterogeneous catalysis mesoporous materials |
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