多孔s区金属MOFs材料的孔洞调控及吸附性能研究

Based on the advantages such as low atomic weight, high abundance, being friendly to environment and so on,partial s-block metal centers (alkali metal centers: Li+, Na+ and K+; alkaline earth metal centers: Be2+, Mg2+ and Ca2+) are new candidates for the construction of porous metal-organic frameworks (MOFs) with the merits of high efficiency, low cost, being environmental-friendly. The key problem, how to implement the designability, adjustability and decoration of the pore size, shape and chirality in order to achieve the high efficiency, selectivity and specificity of the sorption property of porous materials, are urgent to be solved at present. In this project, a series of bulky multi-carboxylate ligands with low symmetry will be designed, synthesized and applied with s-block metal centers to construct porous MOFs. Then, we will study the effect of the conformation of the ligand backbone, the numbers and space position of functional groups on the pore size, shape and chirality and reveal the regulation rules between them. Furthermore, the sorption properties of porous MOFs will be investigated and we will expound on the structure-properties relationship between pore structural characteristics and sorption property by combining the Grand Canonieal Monte Carlo simulations. These will provide the theoretical basis in order to find the more effective materials for gas storage and separation.

部分s区金属元素具有密度小、储量丰富和对环境友好等诸多优点，有望利用其构筑高效、经济和环保的多孔MOFs材料。但如何实现此类多孔材料中孔洞尺寸、形貌或手性的可设计性、可调节性及可修饰性，以达到材料吸附功能的高效性、选择性和专一性仍然是当前急需解决的关键问题。本项目拟设计和合成系列具有大骨架、低对称性的多羧酸配体，与s区金属离子结合，构筑得到一系列多孔s区金属MOFs材料；揭示配体骨架构象、官能团数量和空间位置等因素对孔洞尺寸、形状或手性的调控规律；测试多孔材料的气体吸附性能，结合巨正则系综蒙特卡罗模拟计算方法，阐明孔道结构特征与吸附性能之间的构效关系，为寻找有效的气体储存和分离材料提供理论依据。

本项目按计划执行，采用多种具有不同体积的三元羧酸配体，与s区Li+、Na+、Mg2+和Ca2+金属离子成功组装了一系列结构新颖的s区多孔MOFs材料。揭示了配体骨架、合成条件等因素对孔洞尺寸和形状的调控规律，并对其中具有高物理化学稳定性的多孔s区MOFs进行了气体吸附性能研究，得到了对该领域研究具有实际指导意义的实验结果和科学规律。本项目取得了以下几项代表性成果：1）系统分析了配体臂长对多孔MOF孔道大小及形状的影响；2）首次利用超临界干燥仪成功将CO2分子包结到多孔MOF的孔道中，阐明了MOF材料的CO2吸附行为；3）合成了首例具有六次对称性通道型介孔MOF，并可用于制成循环使用的超级电容器电极材料；4）利用可预知的大体积金属SBUs，通过调整配体的对称性合成得到一个具有双形通道型微/介孔MOF，其对过渡和稀土金属离子展现出不同的反应性，并分别实现了对母体MOF材料吸附及荧光性能的优化。在本项目资助下，发表了SCI收录论文15篇，获得授权发明专利1项，公开授权发明专利3项，培养硕士研究生4人，毕业2人。