手性MOFs催化外消旋仲醇的氧化动力学拆分

Oxidative kinetic resolution (OKR) of racemic secondary alcohols is one of the significant methods to obtain optically pure secondary alcohols. In this work, to improve the stability of MOF based catalyst and facilitate homogeneous catalyst separation and reutilization, series of novel chiral metal-organic framework (MOF) catalysts are designed and developed for OKR of racemic secondary alcohols. With several chiral ligands (L1, L2, L3) and metal ions (Zn2+, Co2+, Cu2+, Zr2+, etc.), chiral MOF catalysts with different structures and configurations could be obtained. With 1-phenyl ethanol as model substrate, the influence of catalyst structure, configuration, and pore size on OKR reactions would be investigated to screen chiral MOF catalyst of best catalytic performance. Different oxidants especially green ones such as O2, H2O2 would be tried to test the oxidation performance for comparison. Factors including reaction temperature, solvent type and polarity, catalyst loading, pH value of reaction system would be studied to determine optimum reaction parameters. Furthermore, the catalyst system would be applied to various secondary alcohols to examine the utility and generality of this methodology. Based on this, the influence of steric effect, conjugative effect, and pore limitation effect of chiral MOF catalysts on catalytic performance will be investigated in detail. The role of catalyst and the mechanism of OKR process would be explored and confirmed.

外消旋仲醇的氧化动力学拆分是获得光学纯仲醇的有效方法之一。为了提高MOF催化剂的稳定性并解决均相催化剂与产物的分离以及循环使用问题，本课题拟采用不同的手性配体（L1，L2，L3）和中心金属盐（Zn2+，Co2+，Cu2+，Zr2+等）制备出多种不同结构与构型的手性MOFs催化剂，用于仲醇的氧化动力学拆分。以简单易得的1-苯基乙醇的氧化动力学拆分为模型反应，研究不同结构、构型、孔尺寸催化剂的催化效果；对比多种氧化剂特别是绿色氧化剂O2、H2O2的氧化效果，研究反应温度、溶剂极性、催化剂用量、体系pH值等因素对催化性能的影响，确定反应最佳工艺条件；改变仲醇取代基的种类，研究手性MOF催化剂对氧化动力学拆分反应的普适性；以不同结构、构型、孔尺寸的手性MOFs催化的反应，研究催化剂空间位阻效应、共轭效应、孔限制效应等因素对催化效果的影响，探索反应过程中催化剂的作用机制。

近年来，金属有机骨架材料(MOFs) 由于具有较高的比表面积、丰富的拓扑结构、可调变的孔尺寸等优点，在气体吸附与分离、药物传递、光学、电学以及催化等领域表现出具有潜在的应用价值。特别是在催化领域方面，发展尤为迅猛，其较高的催化活性和绿色可重复回收性深受科学家们的青睐。本项目设计合成了三种基于MOF的高效催化剂：以UiO系列金属有机骨架为前驱体，利用双溶剂还原法制备得到Pd@UiO复合材料，用于催化膦氧取代联烯芳基醚与炔烃的偶联反应，高效构建了膦氧取代的共轭烯炔类化合物，并探讨可能的反应机理；设计合成了不同比例的Bi2MoO6/NH2-MIL-125(Ti)复合催化剂用于光催化降解有机污染物研究，协同作用使光生载流子在两组分间实现高效分离，降低光生载流子的复合率；以沸石咪唑类金属有机框架ZIF-67为前驱体，在氮气氛围下热解得到了核壳结构Pd-Co/CN@SiO2复合材料，用于芳硝基化合物、烯烃、肉桂醛及其衍生物的常温常压加氢反应，有着广阔的工业应用前景。本项目分别研究了MOF作为载体、复合催化剂及金属/碳骨架模板参与催化的多种方法，对于设计新型基于MOF的高效催化剂具有重要的指导价值。