基于分子笼构筑单元的金属有机骨架及其气体分离性能研究

In recent years, the study of metal-organic frameworks (MOFs) is attracting broad interest of scientists working in fields of chemistry and materials science due to their potential applications in gas storage and separation, catalysis, sensing, and so on. Even if a significant advance in this topic, the rational design and synthesis of these molecule-based materials with specific structures and/or desired properties/functions for particular applications is still challenging to date. On the basis of our previous work in related topics, this project is going to study a new class of MOFs with molecular metal-organic polyhedral (MOPs) cages acting as building unites. Our motivation is to obtain several series of novel porous adsorbent materials for specific gas adsorption and separations. Particularly, we focus on the design and construction of MOFs materials for CO2 capture and H2 purification. By designing at the molecular level, we firstly synthesize organic ligands, and then use them to construct MOFs under suitable conditions, which insure the given coordination linkage of metal ions or clusters and organic ligands. Three strategies are proposed to construct these new classes of MOFs with distinct features: 1) stepwise syntheis from MOPs; 2) one-pot synthesis based on pre-desinged MOPs units; and 3) functionalized Zr(IV)-based MOFs. In this project, we study the preparation conditions of these MOFs, their structures and pore properties, and their performances in CO2/N2，CO2/CH4 and H2/CO2 selective adsorption and separations. We investigate the influences of ligand modifications on the structures and properties/functions of resulting MOFs, the impact of special organic functional groups in pore surface of MOFs on their gas adsorption properties, the relationship between pore properties and gas separation performances of resulting MOFs, as well as their stability and recycling etc. We explore the general rules behind constructing this specific class of MOFs and their applications in the field of gas adsorption and separation; and further understand the mechanism of gas selective adsorption of these materials and the relationship between different factors contributing to the final selectivities. Results from this project would also be important in guiding the design and synthesis of other porous materials for particular applications, such as gas separations.

近年来，金属有机骨架的研究受到极大关注，但设计合成具有特定结构和功能的这类材料仍极具挑战性。本项目拟在申请人近年科研工作的基础上，研究一类以分子笼为超构筑单元的金属有机骨架材料，以期获得具有良好气体分离能力的新型多孔材料。以气体分离（主要是CO2捕获和H2纯化）功效为导向，从分子层次设计入手，以配体合成及其与金属离子特定配位构筑为出发点，通过三种不同策略设计合成各具特色的这类材料。研究它们的合成条件、结构特征、微孔性质、CO2/N2，CO2/CH4，H2/CO2等选择性吸附与分离功能；配体微调对所得化合物结构和功能的影响；特殊功能团对气体吸附所起的作用；材料孔性质与吸附分离表现的关系；及材料的稳定性等。探索构筑这类分子基材料的一般规律及其在吸附领域中的应用；并进一步深入理解气体选择性吸附的内在机理和各因素的平衡关系等。相关研究成果也将对探索其它微孔材料的定向设计与合成具有重要指导意义。

金属有机骨架（MOF）材料近年来受到极大关注。目前这一领域的研究重点包括功能导向的结构调控、性能研究及实际应用探索等。本项目通过配体设计合成了几例结构新颖的核壳型金属有机多面体（MOP）分子笼化合物，同时，以MOP和其它一些优选构筑单元合成了系列含有MOP构筑单元的MOFs。一些MOFs在水甚至酸碱水溶液中具有极高的结构稳定性，表现出良好的选择性气体吸附性能，或对水中抗生素和硝基爆炸物极灵敏的检测能力。此外，提出了一种简单通用的原位自组装模板剂法，成功制备了20多种稳定的多级孔MOF材料，为MOF材料孔内传质慢，大分子分离和催化功能受限等问题提供潜在解决思路。除MOFs设计合成及吸附分离研究外，项目研究内容还在MOF（或MOP）膜制备及膜分离和色谱分离方面进行了拓展。发展了配位驱动原位自组装法制备MOF杂化膜，获得了多种高质量的新型杂化膜，部分膜具有良好的大分子纳滤性能，有极大的应用前景。也发展了取向纳米阵列辅助成膜方法，可控制备了多种气体分离性能良好的MOF薄膜。将高稳定UiO-66，MIL-53(Al)等MOFs制备成HPLC柱，用于苯系物、多环芳烃、邻苯二甲酸酯等体系的分离，效果良好。在本项目资助下，研究结果迄今共发表学术论文38篇，其中SCI收录论文35篇（影响因子大于10的一区论文9篇），部分论文发表在Nature Commun., J. Am. Chem. Soc.，Angew. Chem. Inter. Ed.，Energy Environ. Sci.，Adv. Mater., Chem. Soc. Rev.等期刊上；参编专著章节2章，申请中国发明专利5项，其中1项已授权。项目执行期间，获国家自然科学二等奖1项（第2完成人），获中国石油和化学工业联合会青年科技突出贡献奖、侯德榜化工科技青年奖、茅以升北京青年科技奖等；项目负责人入选国家百千万人才工程、中青年科技创新领军人才等；培养博士后4名、博士生6名、硕士生8名。