N lone-pair⋯π interaction: a rotational study of chlorotrifluoroethylene⋯ammonia

Abstract

The rotational spectra of four isotopologues of the adduct C₂F₃Cl–NH₃ show that NH₃ is bound to the partner molecule through a (N)lone-pair⋯π interaction. Ammonia is located in proximity to the C2 atom (the one linked to two fluorine atoms), with the C2⋯N distance = 2.987(2) Å. The nuclear hyperfine structure due to the quadrupole coupling effects of ³⁵Cl/³⁷Cl and ¹⁴N nuclei has been fully resolved. The ¹⁴N quadrupole coupling constants allow estimating the effective orientation of NH₃ in the complex.