Optimizing Fe‐Based Metal‐Organic Frameworks through Ligand Conformation Regulation for Efficient Dye Adsorption and C<sub>2</sub>H<sub>2</sub>/CO<sub>2</sub> Separation
Xiurong Zhang, Weidong Fan, Weifeng Jiang, Yue Li, Yutong Wang, Ming‐Yue Fu, Daofeng Sun
Abstract
Abstract Regulating the structure of metal‐organic frameworks (MOFs) by adjusting the ligands reasonably is expected to enhance the interaction of MOFs on special molecules/ions, which has significant application value for the selective adsorption of guest molecules. Herein, two tricarboxylic ligands H 3 L−Cl and H 3 L−NH 2 were designed and synthesized based on the ligand H 3 TTCA by replacing part of the benzene rings with C=C bonds and modifying the chlorine and amino groups on the 4‐position of the benzene ring. Two 3D Fe‐MOFs ( UPC‐60‐Cl and UPC‐60‐NH 2 ) with the new topology types were constructed. As the C=C bonds of the ligands have flexible torsion angles, UPC‐60‐Cl features three types of irregular 2D channels, while UPC‐60‐NH 2 has a cage with two types of windows on the surface. The synergistic effect of unique channels and modification of functional groups endows UPC‐60‐Cl and UPC‐60‐NH 2 with high adsorption capacity for organic dyes. Compound UPC‐60‐Cl shows high adsorption capacity for CV (147.2 mg g −1 ), RHB (100.3 mg g −1 ), and MO (220.9 mg g −1 ), whereas UPC‐60‐NH 2 exhibits selective adsorption of MO (158.7 mg g −1 ). Meanwhile, based on the diverse pore structure and modification of active sites, UPC‐60‐Cl and UPC‐60‐NH 2 show the selective separation of equimolar C 2 H 2 /CO 2 . Therefore, reasonable regulation of organic ligands plays a significant role in guiding the structure diversification and performance improvement of MOFs.