Synthesis, structure and gas adsorption properties of a stable microporous Cu-based metal-organic framework assembled from a T-shaped pyridyl dicarboxylate ligand

摘要

A three-dimensional microporous metal-organic framework assembled from a T-shaped pyridyl dicarboxylate ligand, 4'-(pyridin-4-yl)-1,1'-biphenyl-3,5-dicarboxylic acid (H2PBPD), has been successfully synthesized via solvothermal reaction with copper(II) nitrate. Compound 1 was characterized by X-ray single-crystal diffraction, elemental analysis, IR spectroscopy and thermogravimetric analyses. Single-crystal X-ray diffraction analysis indicates that compound 1 is a (3,6)-connected three-dimensional framework with the point symbol {4(2)center dot 6} 2{4(4)center dot 6(2)center dot 8(6)center dot 10(3)}. In the framework of this compound, there exist two large metal-ligand cages. Stability tests show that compound 1 keeps its crystal structure after being soaked in several organic solvents or calcined at 250 degrees C under air atmosphere. The N-2 adsorption at 77 K shows that compound 1 is microporous with a BET surface area of 1682 m(2) g(-1). Compound 1 possesses high adsorption capacities for CO2 (114 cm(3) g(-1), 273 K) under ambient pressure. The test of CO2 cyclic adsorption and regeneration of 1 shows that it has a stable CO2 adsorption capacity and no obvious weight change after doing this ten times.