Porous MOF with Highly Efficient Selectivity and Chemical Conversion for CO2

A new Co­(II)-based MOF, {[Co2(tzpa)­(OH)­(H2O)2]·DMF}n (1) (H3tzpa = 5-(4-(tetrazol-5-yl)­phenyl)­isophthalic acid), was constructed by employing a tetrazolyl-carboxyl ligand H3tzpa. 1 possesses 1D tubular channels that are decorated by μ3–OH groups, uncoordinated carboxylate O atoms, and open metal centers generated by the removal of coordinated water molecules, leading to high CO2 adsorption capacity and significantly selective capture for CO2 over CH4 and CO in the temperature range of 298–333 K. Moreover, 1 shows the chemical stability in acidic and basic aqueous solutions. Grand canonical Monte Carlo simulations identified multiple CO2-philic sites in 1. In addition, the activated 1 as the heterogeneous Lewis and Brønsted acid bifunctional catalyst facilitates the chemical fixation of CO2 coupling with epoxides into cyclic carbonates under ambient conditions.本研究采用四唑-羧酸配体H₃tzpa（5-(4-(四唑-5-基)苯基)间苯二甲酸），构筑了一例基于二价钴（Co(II)）的金属有机框架（Metal-Organic Framework, MOF）{[Co₂(tzpa)(OH)(H₂O)₂]·N,N-二甲基甲酰胺（DMF）}ₙ（1）。该配合物1具有一维管状孔道，孔道内壁由μ3-羟基桥基、未配位的羧酸氧原子以及脱去配位水分子后形成的开放金属位点修饰，在298~333 K温度区间内展现出优异的二氧化碳（CO₂）吸附性能，且相较于甲烷（CH₄）与一氧化碳（CO），对二氧化碳具备显著的选择性捕获能力。除此之外，该配合物1在酸性及碱性水溶液中均具有良好的化学稳定性。巨正则蒙特卡洛（Grand canonical Monte Carlo）模拟证实，该配合物1中存在多个亲二氧化碳位点。进一步而言，经活化脱除配位水分子后的样品1作为非均相路易斯-布朗斯特酸双功能催化剂，可在常温常压条件下高效催化二氧化碳与环氧化物的环加成固定反应，生成环状碳酸酯产物。