具有介孔结构的有机金属催化剂合成及其不对称催化反应研究

【作者】 姚美；

【导师】 刘国华；

【作者基本信息】 上海师范大学 ， 有机化学， 2008， 硕士

【摘要】 具有介孔结构的纳米材料SBA-15作为一类新型载体材料广泛应用于手性配体和金属催化剂的负载化。这不仅解决了昂贵手性配体和金属催化剂的分离和再利用的问题;更重要的是,可以利用介孔金属催化剂的孔道的限域效应改善催化手性中的催化微环境,提高不对称催化的活性和光学选择性。因此,研究具有介孔结构的纳米金属催化剂为开拓高效手性催化和手性分离提供新的契机。我们以后嫁接法把有机金属络合物嫁接到载体SBA-15上,合成了具有介孔结构的手性Ru和Ir催化剂,并系统研究了介孔金属催化剂的表面性质、纳米孔结构、金属催化中心对材料催化性能的影响。在潜手性芳香酮的不对称转移反应中,催化剂Ru-SBA-15/（R,R）-DPEN6得到很高的活性（ >99%yields ）和立体选择性（>98%ee）。催化剂Ir-SBA-15/（R,R）-DPEN6在40atmH₂下,对各种芳香酮的不对称氢化反应中,展示了优秀的催化活性（>95%）和立体选择性（>99%）。合成的催化剂易回收和重复使用达七次,且没有明显影响催化活性和选择性。更多还原

【Abstract】 Mesoporous structure of the SBA-15 nanomaterials as a new type of supported materials widely used in chiral ligands and supported metal catalyst .It does not only solve the expensive chiral ligands and metal catalyst separation and reuse issues; But also we can use the limiting space of the channels in mesoporous metal catalysts to improve catalytic domain of chiral catalysts in the micro-environment and improve asymmetric catalytic activity and enantio- selectivity.Mesoporous silica-supported chiral Ru and Ir catalysts with highly ordered dimensional-hexagonal mesostructure was prepared by postgrafting organometallic complex on SBA-15.we study the influences of the surface properties,the mesostructures and the metals of chiral complex on the catalytic performance of the materials.During asymmetric transfer hydrogenation of aromatic ketones ,the mesoporous silica-supported chiral Ru catalyst exhibited high catalytic activity (more than 99% conversions) and excellent enantioselectivity (up to more than 98% ee).During asymmetric hydrogenation of various aromatic ketones under 40atm H2, the mesoporous silica-supported chiral iridium catalyst exhibited high catalytic activity (more than 95% conversions) and excellent enantioselectivity (up to more than 99% ee). Such catalysts could be recovered easily and used repetitively seven times without significantly affecting the catalytic activity and the enantioselectivity.更多还原