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

The hydrogen-bonded heterodimer 7-oxabicyclo[2.2.1]heptane ... HCl (OBH ... HCl) has been investigated using a molecular beam Fourier-transform microw ave spectrometer. The ground state rotational spectra of the OBH ... (HCl)- Cl-35, OBH ... (HCl)-Cl-37 and OBH ... (DCl)-Cl-35 isotopomers have been st udied in the frequency range 6-18.5 GHz. Spectral analysis gave rotational, quartic centrifugal distortion constants and the complete Cl-nuclear quadr upole coupling tensor for all isotopomers. A C-s symmetry has been establis hed 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 phi between the OBH C-2 axis and the O ... H bond direction were found to be 1.764(29) Angstrom and 129.7(37)degrees, respectively. A small deviation of the linea rity of the atoms O ... H-Cl involved in the hydrogen bond, theta = 7(4)deg rees, was observed. Ab initio calculations were also performed to complemen t the experimental work.