A porous Zn(II)-coordination polymer based on tetracarboxylic acid exhibiting selective CO2 adsorption and iodine uptake

A porous Zn(II)-coordination polymer, {[Zn2(μ8-abtc)(betib)]•DMF}n (1), was solvothermally synthesized with 3,3′,5,5′-azobenzenetetracarboxylate (abtc4-) and 1,4-bis(imidazol-1-yl)butane (betib) ligands and {[Zn2(μ8-abtc)(betib)]•H2O}n (2) was obtained through immersing of 1 in methanol. Compounds 1 and 2 were structurally characterized by various techniques. Both compounds displayed 3D porous framework with 3,6-connected sqc5381 net. Compound 2a obtaining at 140oC from 2 exhibited gas and iodine adsorption properties. Interestingly, the compound adsorbed selectively CO2 with the uptake capacity of 54.02 cm3 g-1 (13.26 %) over N2 (5.43 cm3 g-1) and CH4 (14.53 cm3 g-1) at 273 K. The compound also adsorbed the iodine with the weights of 19.99 % and 30.26 % in solution and vapor phase, respectively. Single crystal X-ray result and Raman spectra showed the presence of 1D iodine chains in the pores of framework.