Observation and Properties of the Hydrogen-Bonded Heterodimer Tetrahydrothiophene···HCl

Abstract

The ground-state rotational spectra of five isotopic species, C4H832S···H35Cl, C4H832S···H37Cl, C4H832S··· D35Cl, C4H832S···D37Cl, and C4H834S···H35Cl, of a hydrogen-bonded dimer between tetrahydrothiophene and hydrogen chloride have been measured in the frequency range 6−18.5 GHz using a molecular beam Fourier transform microwave spectrometer. Spectral analysis gave rotational, quartic centrifugal distortion and Cl−nuclear quadrupole coupling constants for each isotopomer. The rotational and quadrupole coupling constants have been interpreted in terms of a geometry in which hydrogen chloride lies on the plane bisector to the CSC angle of tetrahydrothiophene. The angle between the S···Cl internuclear line and the line bisecting the CSC angle was found to be 86.6(7)° and the distance r(S···Cl) = 3.48(3) Å. The deviation of the atoms S···H−Cl involved in the hydrogen bond from a collinear arrangement (θ = 0°) was estimated to be θ ∼ 14°.