Polar Acylamide Functionalized Porous Cu-MOFs for Sustainable and Selective Carbon Dioxide Sorption and Separation at Ambient and High Pressure

Abstract

Metal–organic frameworks with suitable voids and polar functional group are expectant candidates for their excellent carbon dioxide uptake. Herein, two new polar acylamide-functionalized three-dimensional Cu(II)-MOFs have been synthesized, namely, {[Cu2(4-pmi)(glut)2]·(H2O)8}n (1) and {[Cu(4-pmi)(2-ntp)]·(H2O)4}n (2) (4-pmi = pyridine-4-yl-methylene-isonicotinohydrazide, glut = glutarate, and 2-ntp = 2-nitroterephthalate). The dehydrated framework of these two materials demonstrates a moderately high carbon dioxide uptake at ambient pressure (1 bar and 195 K) and high pressure (20 bar and 273 K) for both compounds, 1 and 2. Excitingly, high pressure carbon dioxide sorption of these two compounds, 1 and 2, shows high uptake of 187 and 233 cc/g, respectively. Here, the favorable pore-centric orientation of the acylamide functional group and interaction with the quadruplolar carbon dioxide molecule make such unprecedented results of carbon dioxide sorption. These compounds will be an appropriate commander for their potential application of selective and sustainable carbon dioxide scavenging from industrial flue gas and natural gas.