Two Stable Sodalite-Cage-Based MOFs for Highly Gas Selective Capture and Conversion in Cycloaddition Reaction.

Stable metal-organic frameworks, containing periodically arranged nanosized cages or pores and active Lewis acid-base sites, are considered ideal candidates for efficient heterogeneous catalysis. Herein, based on the light of reticular chemistry design principles, the ingenious assembly of two pyridine N-rich multifunctional triangular linkers, H 3 TBA [3,5-di (1h-tetrazol-5-yl) benzoic acid] and H 2 TZI [5-(1H-tetrazol-5-yl)isophthalic acid], with Mn II formed PCP-33(Mn) and PCP-34(Mn), respectively. PCP-33(Mn) and PCP-34(Mn) are typical sod topology zeolitic metal-organic frameworks (ZMOFs) with hierarchical tetragonal micropores and metal organic polyhedral sodalite-like cages. The inner walls of these cages are modified by open metal sites Mn II and Lewis acid-base sites of halide ions and N pyridine atoms. The characteristics of the cages' structures make two MOFs exhibit high surface area and a small window, which promote their outstanding gas capture ability (C 2 H 2 , 131.8 cm 3 g -1 ; CO 2 , 77.9 cm 3 g -1 at 273 K) and selective separation performance (C 2 H 2 /CH 4 , 226.2, CO 2 /CH 4 , 50.3 at 298 K), and are also suitable as catalytic reactors for metal/solvent-free chemical fixation of CO 2 with epoxides to achieve high-efficiency CO 2 conversion. Furthermore, they are greatly recyclable for several cycles while retaining their structural rigidity and catalytic activity.