Tetrazole‐Functionalized Zirconium Metal‐Organic Cages for Efficient C2H2/C2H4 and C2H2/CO2 Separations

• Published in: Angewandte Chemie International Edition 2021-08, Vol.60 (32), p.17338-17343
• Main Authors: Fan, Weidong, Peh, Shing Bo, Zhang, Zhaoqiang, Yuan, Hongye, Yang, Ziqi, Wang, Yuxiang, Chai, Kungang, Sun, Daofeng, Zhao, Dan
• Format: Article
• Language: English
• Subjects: Cages; Carbon dioxide; Complications; Density functional theory; DFT calculations; Gas separation; isoreticular chemistry; metal-organic cages; Porous materials; Synthesis; tetrazole functionalization; Tetrazoles; Zirconium
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.202102585

Isoreticular functionalization is a well‐elucidated strategy for pore environment tuning and the basis of gas separation performance in extended frameworks. The extension of this approach to discrete porous molecules such as metal‐organic cages (MOCs) is conceptually straightforward but hindered by synthetic complications, especially stability concerns. We report the successful isoreticular functionalization of a zirconium MOC with tetrazole moiety by bottom‐up synthesis. The title compound (ZrT‐1‐tetrazol) shows promising C2H2/CO2 and C2H2/C2H4 separation performance, as demonstrated by adsorption isotherms, breakthrough experiments, and density functional theory calculations. The design analogy between MOFs and highly stable MOCs may guide the synthesis of novel porous materials for challenging separation applications. We report the use of isoreticular chemistry to synthesize a tetrazole‐functionalized metal‐organic cage (ZrT‐1‐tetrazol) with the same structure of ZrT‐1 and ZrT‐1‐NH2. The adsorption capacity of ZrT‐1‐tetrazol for C2H2 increases by 130 % (298 K) compared with ZrT‐1‐NH2, and it exhibits promising C2H2/CO2 and C2H2/C2H4 separation performance.