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Published on: August 13, 2020
Conformational Equilibria of 2-Methoxypyridine⋅⋅⋅CO2 : Cooperative and Competitive Tetrel and Weak Hydrogen Bonds
Wanying Cheng1, Yang Zheng1, Sven Herbers1
1Department of Chemistry, School of Chemistry and Chemical Engineering, Chongqing University, No.55 Daxuecheng South Rd., Shapingba, 401331, Chongqing, China.
Abstract:
The rotational spectrum of 2-methoxypyridine⋅⋅⋅CO2 was recorded and analysed employing a cavity-based Fourier transform microwave spectrometer, complemented with quantum chemical calculations which predicted three possible isomers within energies less than 1000 cm-1 . The two most stable isomers were observed in the pulsed jet, which are stabilized by a network of C⋅⋅⋅N/O tetrel and C-H⋅⋅⋅O weak hydrogen bonds. The relative population ratio of the two detected isomers was estimated to be NI /NII ≈2.5. The competition and cooperation of the present non-covalent interactions in both isomers are discussed within the framework of Bader's quantum theory of atoms in molecules and Johnson's non-covalent interaction analyses. The study shows, that when looking for CO2 adsorbents, one might prefer candidates with multiple interactions in one site over candidates with few but strong interactions.
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