A new Co(II) metal–organic framework with enhanced CO2 adsorption and separation performance
The new functional ligand 5-(1H-pyrazole-4-carboxamido)isophthalic acid (H3L) reacts with CoSO4·7H2O to form a new three-dimensional metal–organic framework, [Co4(HL2−)4(DMF)2(H2O)2]n·solvent (1) with a new (3,6)-connected topology. 1 exhibits one-dimensional polar channels with approximate dimensions of 6.0 × 8.0 Å2 decorated with accessible functional sites. These sites contribute to enhanced CO2 uptake (103.2 cm3 g−1 at 273 K and 1 bar) and CO2/CH4 selectivity (7.25 for CO2/CH4 = 50:50; 8.59 for CO2/CH4 = 5:95) at 298 K and 1 bar. DFT calculations were also performed to elucidate the binding sites. These results suggest that complex 1 is an attractive candidate for CO2 adsorption and separation.