engleski

Rational design of porous organic materials based on azo, azoxy and azodioxy linkages for the selective adsorption of CO2 over N2

The rising emissions of CO2 have a dramatic impact on the environment, such as global warming and sea level rising. Porous organic materials based on nitrogen-nitrogen linkages recently emerged as a suitable alternative for the selective adsorption of CO2 over N2. In comparison to amorphous azo-linked covalent organic polymers, it was shown that self-addition polymerizations of polynitroso monomers resulted in crystalline materials due to reversible dimerization reaction of nitroso compounds to cis- or transazodioxides, thus allowing a self- correction of errors during polymerization. Recently, we have focused on the synthesis and application of new functional nitrogen-nitrogen linked porous organic materials. Prior to the synthesis, a comprehensive computational approach including calculation of binding energies, visualization of electrostatic potential maps and using GCMC simulations to obtain adsorption isotherms and density plots was performed using model systems constructed between four different connectors (trisubstituted amine, benzene, pyridine and triazine) and three different nitrogen-nitrogen linkages (azo, azoxy and azodioxy). Such approach provides us with complementary data not accessible through experiments and help us to better understand structural characteristics regarding the efficient and selective adsorption of gases. Different type of stackings between 2D layers made of hexagonal pores may directly affect the adsorption properties of the predicted porous frameworks. Preliminary studies indicated that azodioxy linkages can promote adsorption of CO2 in comparison with other investigated nitrogen- nitrogen linkages having the same arrangement of layers. The results of the computational study were also tested against the experimentally obtained data to verify the potential of the selected nitrogen-nitrogen linked porous organic materials for the selective binding of CO2 over N2.

covalent organic materials, molecular mechanics, DFT, binding energy, CO2 adsorption, gas separation

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