CO2 Adsorption in Fe-2(dobdc): A Classical Force Field Parameterized from Quantum Mechanical Calculations

Abstract

Carbon dioxide adsorption isotherms have been computed for the metal-organic framework (MOF) Fe-2(dobdc), where dobdc(4-) = 2,5-dioxido-1,4-benzenedicarboxylate. A force field derived from quantum mechanical calculations has been used to model adsorption isotherms within a MOF. Restricted open-shell Moller-Plesset second-order perturbation theory (ROMP2) calculations have been performed to obtain interaction energy curves between a CO2 molecule and a cluster model of Fe-2(dobdc). The force field parameters have been optimized to best reproduced these curves and used in Monte Carlo simulations to obtain CO2 adsorption isotherms. The experimental loading of CO2 adsorbed within Fe-2(dobdc) was reproduced quite accurately. This parametrization scheme could easily be utilized to predict isotherms of various guests inside this and other similar MOFs not yet synthesized.