Experimental and Density Functional Theory Studies on the Adsorption Behavior of Selected Gas Molecules on Mg(II) Coordination Polymer Constructed with 1,3,5-Benzenetricarboxylates

An optimized structure of Mg(H2BTC)2(H2O)2, 2 derived from Mg(II)-1,3,5-benzenetricarboxylates with the composition Mg(H2BTC)2(H2O)4, 1 (CCDC 1998471) by elimination of two coordinated aqua ligand, was used to adsorbed selected gas molecules. The adsorption behavior of selected gas molecules (N2, NO2, NO, NH3, H2, O2, CO, CO2) on the optimized structure was investigated using the density functional theory (DFT). Different adsorption configurations screened had favorable adsorption energies while retaining their initial molecular geometries and the gas molecules are said to be physically adsorbed. The quantum chemical descriptors for the adsorbed molecules were studied and analyzed. The density of states (DOS) and the partial density of states (PDOS) calculated for the different adsorption configurations showed that NO2, CO, CO2 interacted strongly with the Mg(H2BTC)2(H2O)2 complex, while the interactions of NH3, NO, H2 and O2 were found to be weak. Overall, the coordination polymer Mg(H2BTC)2(H2O)2 has proven to be good material for storage of gases.