CO2 and Iodine Uptake Properties of Co(II)-Coordination Polymer Constructed from Tetracarboxylic Acid and Flexible Bis(imidazole) Linker

A new coordination polymer, formulated as {[Co2(μ8-abtc)­(betib)]·DMF} n (1) (abtc, 3,3′,5,5′-azobenzenetetracarboxylate; betib, 1,4-bis­(2-ethylimidazol-1-yl)­butane), was synthesized with 3,3′,5,5′-azobenzenetetracarboxylic acid and flexible betib ligand. Complex 1 was immersed in methanol to obtain {[Co2(μ8-abtc)­(betib)]·H2O} n (2). The complexes were characterized by IR spectra, elemental analyses, single-crystal and powder X-ray diffractions, and thermal analyses. X-ray results demonstrated that complexes 1 and 2 had a porous 3D framework with sqc5381 net. Complex 2 was activated at 105 °C (2a), and CO2 and iodine adsorption properties of 2a were studied. The CO2 uptake capacity of 2a was 52.94 cm3/g (10.40%). Moreover, complex 2a encapsulated 30.34 and 21.98% iodine in the vapor phase and solution, respectively, which corresponded to 1.975 and 1.42 molecules of iodine per formula unit, respectively.