Computational studies on the adsorption of CO₂ in the flexible perfluorinated metal-organic framework zinc 1,2-bis(4-pyridyl)ethane tetrafluoroterephthalate

Carbon dioxide adsorption sites within the flexible metal-organic framework (MOF) zinc 1,2-bis(4-pyridyl)ethane tetrafluoroterephthalate (Znbpetpa) were investigated using density functional theory (DFT) and canonical Monte Carlo (MC) calculations. Two types of sites with different heats of adsorption were found by using DFT and confirmed by the MC results. Expansion of the cavities occurred simultaneously with gas uptake and the process of "breathing" within the MOF was identified. The presence of such a mechanism makes the understanding of this structure useful in tuning the design of MOFs for permanent trapping of gases.