Tuning the interaction strength and the adsorption of CO2 in metal organic frameworks by functionalization of the organic linkers

The interaction strength of CO2 with a set of fourteen, strategically selected, functional groups was investigated by performing MP2 calculations. These functional groups potentially can be incorporated in MOF linkers. Initially, the energetically most favorable intermolecular structures for each of the CO2 functional group complexes were found, starting from several different initial configurations of CO2 over the functional groups. Among the functional groups that were considered, the highest interaction energy (-5.4 kcal/mol) with CO2 was found for phenyl hydrogen sulfate (OSO3H), which is almost 2 times larger than the corresponding binding energy for benzene (-2.9 kcal/mol). Electrostatic potential maps of the functionalized benzenes and electron redistribution density plots of the corresponding complexes with CO2 were generated to understand the nature of the interaction of CO2 with the functionalized benzenes. Additionally, we tried to find any correlations between the obtained binding energies and the geometrical parameters of the CO2 functional group complexes. The best functional groups were tested for their ability to capture CO2 at 298 K for a wide pressure range by performing GCMC simulations. (C) 2016 Elsevier Inc. All rights reserved.