Modulation of the strength of weak S-H⋯O hydrogen-bond: Spectroscopic study of the complexes of 2-flurothiophenol with methanol and ethanol.

Autor:	Metya S; Department of Chemistry, Indian Institute of Science Education and Research Pune, Dr. Homi Bhabha Road, Pashan, Pune 411008, India., Roy S; Department of Chemistry, Indian Institute of Science Education and Research Pune, Dr. Homi Bhabha Road, Pashan, Pune 411008, India., Mandal S; Department of Chemistry, Indian Institute of Science Education and Research Pune, Dr. Homi Bhabha Road, Pashan, Pune 411008, India., Huang QR; Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, Taiwan., Kuo JL; Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, Taiwan., Das A; Department of Chemistry, Indian Institute of Science Education and Research Pune, Dr. Homi Bhabha Road, Pashan, Pune 411008, India.
Jazyk:	angličtina
Zdroj:	The Journal of chemical physics [J Chem Phys] 2024 Jun 14; Vol. 160 (22).
DOI:	10.1063/5.0208086
Abstrakt:	Spectroscopic exploration of sulfur-centered hydrogen bonding involving a thiol group (S-H) as the hydrogen bond donor is scarce in the literature. Herein, we have investigated 1:1 complexes of 2-fluorothiophenol (2-FTP) with methanol (MeOH) and ethanol (EtOH) in the gas phase to examine the physical characteristics and strength of the S-H⋯O hydrogen bond. Structures, conformations, and the strength of the S-H⋯O interaction are investigated by measuring the electronic and Infrared (IR) spectra of the two complexes employing resonant two-photon ionization, UV-UV hole-burning, and IR-UV double resonance spectroscopic techniques combined with quantum chemical calculations. Three conformers of 2-FTP⋯MeOH and two conformers of 2-FTP⋯EtOH have been detected in the experiment. A comparison of the IR spectra obtained from the experiment with those of the low-energy conformers of 2-FTP⋯MeOH and 2-FTP⋯EtOH predicted from the theory confirms that all the observed conformers of the two complexes are primarily S-H⋯O hydrogen bonded. The IR red-shifts found in the S-H stretching frequencies in 2-FTP⋯MeOH and 2-FTP⋯EtOH concerning that in 2-FTP are ∼76 and ∼88 cm-1, respectively, which are much larger than that was reported earlier in the 2-FTP⋯H2O complex (30 cm-1). The strength and physical nature of different noncovalent interactions, including the S-H⋯O hydrogen bond existing in the complexes, are further analyzed using natural bond orbital analysis, quantum theory of atoms in molecules, and localized molecular orbital-energy decomposition analysis. The current investigation reveals that the S-H⋯O hydrogen bond can be strengthened by judicial choices of the hydrogen bond acceptors of higher proton affinities. (© 2024 Author(s). Published under an exclusive license by AIP Publishing.)
Databáze:	MEDLINE
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