Characterizing hydrogen and tetrel bonds in clusters of CO 2 with carboxylic acids

• Published in: Physical chemistry chemical physics : PCCP Vol. 23; no. 31; pp. 16915 - 16922
• Main Authors: Li, Weixing, Melandri, Sonia, Evangelisti, Luca, Calabrese, Camilla, Vigorito, Annalisa, Maris, Assimo
• Format: Journal Article
• Language: English
• Published: 12.08.2021
• ISSN: 1463-9076; 1463-9084
• DOI: 10.1039/D1CP02568F

The interaction between carbon dioxide and planar carboxylic acids has been investigated through the analysis of the microwave spectrum of the acrylic acid·CO 2 complex and quantum chemical modeling of the R–COOH·(CO 2 ) 1,16 clusters, where R = H, CH 2 CH. As regards the 1 : 1 compounds, two species, involving the s- cis and s- trans conformers of acrylic acid were observed. For both of them, a similar bidentate interaction arises between the carbonyl group of CO 2 and the carboxylic group of the organic acid, leading to the formation of a planar six-membered ring. The binding energy is estimated to be D e ≃ 21 kJ mol −1 , 1/3 being the energy contributions of the tetrel to hydrogen bonds, respectively. In the 1 : 16 clusters, the ring arrangement is broken, allowing for the interaction of the acid with several CO 2 molecules. The CO 2 molecules completely surround formic acid, whereas, in the case of acrylic acid, they tend to avoid the allyl chain.