Elucidating the non-covalent interactions in thiazole–carbon dioxide complexes through rotational spectroscopy and theoretical computations

Abstract

The complexes formed between thiazole and carbon dioxide were studied to probe the non-covalent bonding properties between carbon dioxide and a heteroaromatic ring. The rotational spectra of the thiazole–CO₂ complex were analyzed using a supersonic jet Fourier transform microwave spectrometer in conjunction with theoretical calculations. A rotational spectrum corresponding to the global minimum of the thiazole–CO₂ complex was identified. The observed structure of the complex is stabilized by a C⋯N tetrel-bond, with additional stability provided by a C–H⋯O hydrogen bond. The computational analysis of the thiazole–(CO₂)₂ and thiazole–(CO₂)₃ complexes demonstrated the notable impact of C⋯N interactions on aggregation, with the significance of interactions between CO₂ molecules increasing with the number of CO₂ molecules present. NCI analysis, NBO analysis, and SAPT analysis were utilized to elucidate the properties of non-covalent interactions between thiazole and CO₂, as well as those among CO₂ molecules.