Interaction Energies of CO₂·Amine Complexes: Effects of Amine Substituents

Abstract

To focus on the identification of potential alternative amine carbon capture compounds, CO(2) with methyl, silyl, and trifluoromethyl monosubstituted and disubstituted amine compounds were studied. Interaction energies of these CO(2)·amine complexes were determined via two methods: (a) an ab initio composite method, the correlation consistent composite approach (ccCA), to determine interaction energies and (b) density functional theories, B3LYP/aug-cc-pVTZ and B97D/aug-cc-pVTZ. Substituent effects on the interaction energies were examined by interchanging electron donating and electron withdrawing substituents on the amine compounds. The calculations suggested two different binding modes, hydrogen bonding and acid-base interactions, which arise from the modification of the amine substituents, echoing previous work by our group on modeling protein·CO(2) interactions. Recommendations have been noted for the development of improved amine scrubber complexes.

Insights into the interactions of CO2 with amines: a DFT benchmark study

“…The interaction between CO 2 and amines has been investigated experimentally and theoretically. [8][9][10][11][12][13][14][15][16] Overall, however, there is still some debate regarding the reaction mechanism. The following question remains: does the reaction involve a zwitterion intermediate or a concerted carbamate ion formation?…”

“…13 Previous computations of the interaction energy between CO 2 and amines have been performed almost exclusively using the B3LYP functional. [11][12][13][14][15][16][17][18] It is known, however, that for certain systems, B3LYP does not give the highest quality DFT results compared to higher-level calculation methods, such as the methods including dispersion correction. [19][20][21][22][23][24] Interestingly, even a previous benchmark study on the CO 2 -NH 3 interaction focused on the B3LYP functional as the method of choice.…”

Electronic Interactions in Iminophosphorane Superbase Complexes with Carbon Dioxide

“…It is interesting to extend the comparison to other computations in the literature reported for ED–EA complexes with CO 2 . Compared to amines, for instance, which have been widely investigated for the purpose of carbon dioxide capture, the CH 3 NPH 3 iminophosphorane displays a larger interaction energy with CO 2 and a shorter intermolecular distance. , Jorgensen et al, in particular, studied the complexes with ammonia, methylamine, and dimethylamine. According to their results, the C···N distance amounts 3.0–2.98 Å at the B3LYP/aug-cc-pVTZ level and the interaction energy (calculated as the difference in formation enthalpies at 298 K) around −1 kcal/mol in the three cases (at the same theoretical level).…”

Theoretical Study of the Formation of Complexes Between CO and Nitrogen Heterocycles

“…As a first step to study these families as carbon dioxide sorbents we consider worthwhile to explore, the feasibility of the formation of adducts between the above-mentioned heterocycles and CO 2 from a theoretical point of view. Previous theoretical works have already studied complexes with aminoacids [18,19], amines [4,20], and aromatic compounds such as benzene [21,23], pyrrole and pyridine [23] and other N-containing heterocycles [24]. DFT underestimates the interaction energies between CO 2 and electron donor systems [24].…”