The rotational spectra and structure of the jet-cooled heterodimer 7-oxabicyclo[2.2.1]heptane···HCl

Abstract

The hydrogen-bonded heterodimer 7-oxabicyclo[2.2.1]heptane···HCl (OBH···HCl) has been investigated using a molecular beam Fourier-transform microwave spectrometer. The ground state rotational spectra of the OBH···H³⁵Cl, OBH···H³⁷Cl and OBH···D³⁵Cl isotopomers have been studied in the frequency range 6–18.5 GHz. Spectral analysis gave rotational, quartic centrifugal distortion constants and the complete Cl-nuclear quadrupole coupling tensor for all isotopomers. A C_s symmetry has been established for the complex where the hydrogen chloride lies on the plane bisector to the COC angle of OBH. The distance r(O···H) and the angle φ between the OBH C₂ axis and the O···H bond direction were found to be 1.764(29) Å and 129.7(37)°, respectively. A small deviation of the linearity of the atoms O···H–Cl involved in the hydrogen bond, θ = 7(4)°, was observed. Ab initio calculations were also performed to complement the experimental work.