Microwave spectroscopic and computational analyses of the phenylacetylene�methanol complex: insights into intermolecular interactions

Gupta, S and Cummings, CN and Walker, NR and Arunan, E (2024) Microwave spectroscopic and computational analyses of the phenylacetylene�methanol complex: insights into intermolecular interactions. In: Physical Chemistry Chemical Physics .

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Abstract

The microwave spectra of five isotopologues of phenylacetylene�methanol complex, C6H5CCH�CH3OH, C6H5CCH�CH3OD, C6H5CCH�CD3OD, C6H5CCD�CH3OH and C6H5CCH�13CH3OH, have been observed through Fourier transform microwave spectroscopy. Rotational spectra unambiguously unveil a specific structural arrangement characterised by dual interactions between the phenylacetylene and methanol. CH3OH serves as a hydrogen bond donor to the acetylenic �-cloud while concurrently accepting a hydrogen bond from the ortho C-H group of the PhAc moiety. The fitted rotational constants align closely with the structural configuration computed at the B3LYP-D3/aug-cc-pVDZ level of theory. The transitions of all isotopologues exhibit doublets owing to the methyl group's internal rotation within the methanol molecule. Comprehensive computational analyses, including natural bond orbital (NBO) analysis, atoms in molecules (AIM) theory, and non-covalent interactions (NCI) index plots, reveal the coexistence of both O-H�� and C-H�O hydrogen bonds within the complex. Symmetry adapted perturbation theory with density functional theory (SAPT-DFT) calculations performed on the experimentally determined geometry provide an insight into the prominent role of electrostatic interactions in stabilising the overall structural arrangement. © 2024 The Royal Society of Chemistry.

Item Type:	Journal Article
Publication:	Physical Chemistry Chemical Physics
Publisher:	Royal Society of Chemistry
Additional Information:	The copyright for this article belongs to Royal Society of Chemistry.
Keywords:	Aromatic hydrocarbons; Complexation; Computation theory; Density functional theory; Hydrogen bonds; Microwave spectroscopy; Molecules; Perturbation techniques, Computational analysis; Hydrogen bond donors; Intermolecular interactions; Isotopologues; Microwave spectrum; Phenylacetylenes; Rotational constants; Rotational spectra; Structural arrangement; Structural configurations, Methanol
Department/Centre:	Division of Chemical Sciences > Inorganic & Physical Chemistry
Date Deposited:	18 Dec 2024 09:47
Last Modified:	18 Dec 2024 09:47
URI:	http://eprints.iisc.ac.in/id/eprint/85869

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