Conformational Equilibria of 2-Methoxypyridine...CO2. Cooperative and Competitive Tetrel and Weak Hydrogen Bonds

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 N-I/N-II approximate to 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.

Automated summary

The rotational spectrum of 2-methoxypyridine...CO2 reveals the presence of two stable isomers stabilized by various weak interactions, with a relative population ratio of approximately 2.5. The study emphasizes the importance of multiple interactions in CO2 adsorbents, as opposed to few but strong interactions for enhanced performance. Discussions on non-covalent interactions within isomers are based on Bader's quantum theory of atoms in molecules and Johnson's non-covalent interaction analyses.