New generation of ionic liquids (ILs) based on 1,8-diazobicylo [5,4,0] undec-7-ene, (DBU), is applied as the solvent in organic reactions [1]. In this work, by using a theoretical procedure, we investigated four different DBU-based ILs consisting of DBU as a cation and four different imidazole derivatives as the anions. The results showed that the bond length of the N-C decreases at the transition state, showing that CO2 is absorbed by the ILs. Natural bond orbital (NBO) analysis showed a strong charge transfer between the N atom of the imidazole anion and C atom of the CO2, confirming CO2 absorption. On the basis of the results, DBU superbase and DBU derivative-based ILs are good candidates for CO2 absorption because of high basicity. Finally, DBU based ILs have an excellent ability for CO2 capturing, which is important in chemical industries.

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