Nuclear hyperfine coupling interactions in the rotational spectra of the linear and bent isomers of HF–N 2O

Abstract

The rotational spectra of six isotopomers of the linear and bent isomers of HF–N 2O have been collected in the 7–18 GHz region with a Fourier transform microwave spectrometer. The nuclear hyperfine structure in the spectra produced by HF spin–spin coupling interaction and nuclear quadrupole coupling interactions due to the D nucleus of DF and the 14 N nuclei of N 2O have been resolved and analyzed. In the linear isomer, H in HF is bonded to the terminal N in N 2O. The NF bond lengths are 2.9808(2) Å for the HF-containing isotopomers and 2.9732(2) Å for the DF-containing isotopomers. The zero point angles are 23.1° for HF and 31–34° for N 2O. The hyperfine constants suggest that the HF bond is lengthened by 0.0105 Å upon complexation and that the electric field gradients of the two nitrogen nuclei in N 2O are perturbed differently in the complex. In the bent isomer, the hydrogen bond is formed between HF and O in N 2O. The intermolecular distances are 3.4942(2) Å for the HF-containing isotopomers and 3.4436(2) Å for the DF-containing isotopomers, with HF and N 2O forming angles of 34° and 46°, respectively, with the intermolecular axis. The nuclear quadrupole coupling constants of the two nitrogen nuclei do not indicate electric field gradient perturbation in this isomer.