Multifunctional Cd(II) Metal–Organic Framework with Abundant Lewis Acidic and Basic Sites: Selective Gas Adsorption and Separation, CO2 Catalytic Fixation, and Fluorescence Recognition of Uric Acid

The development of new porous materials for the selective adsorption and fixation of CO 2, as well as the selective capture of C 2 H 2, is essential for environmental protection and energy security. Herein, a versatile coordination polymer, {[Cd(btbpa)(H 2 O)]·3H 2 O·4NMP·DMA} n ( Cd-btbpa, H 2 btbpa = 4,4′-bis(1 H -1,2,4-triazole-1-yl)-[1,1′-biphenyl]-3,3′-dicarboxylic acid), has been prepared, which not only exhibits good chemical and thermal stability but also possesses adaptive nanochannels. Gas uptake studies disclosed the selective adsorption properties of MOF Cd-btbpa for CO 2 and C 2 H 2 over other gases (N 2, CH 4, C 2 H 4, and C 2 H 6 ), contributing to a record-high IAST selectivity of ca. 3905 (50/50 of CO 2 /CH 4, v/v). The adsorption selectivity values for C 2 H 2 /C 2 H 4 and CO 2 /N 2 at 298 K are 2.14 and 41.79, respectively. Breakthrough experiments were carried out to confirm its practical application value for CO 2 /CH 4, CO 2 /N 2, and C 2 H 2 /C 2 H 4 separation. In addition, it can drive heterogeneous cycloaddition of CO 2 with various epoxides under mild conditions (75 °C, 1 atm) and boost the yield of produced cyclic carbonates almost to 100% for the epoxides such as 1,2-epoxybutane and epichlorohydrin. Besides, Cd-btbpa shows excellent recognition ability for uric acid (UA) with high K SV (3.9378 × 10 4 M –1 ) and sensitivity (LOD: 0.14 μM).