Structure and non-covalent interactions of 1,3-difluoropropane and its complex with water explored by rotational spectroscopy and quantum chemical calculations.

1,3-difluoropropane and its complex with water were characterized by using Fourier transform microwave spectroscopy with the aid of quantum chemical calculations. Rotational spectra of the monomer were extended to the ¹³C isotopologues which lead to a precise structural determination of the two observed conformers. For the 1,3-difluoropropane-water complex, the most stable isomer has been observed and assigned in the supersonic jet expansion. In the observed isomer, water acts as a proton donor and a proton acceptor forming one O–H⋯F weak hydrogen bond and two C–H⋯O weak hydrogen bonds, respectively. The measurements on the three ¹³C, ¹⁸O, and deuterated water allowed determination of the skeleton structure and evaluation of the weak hydrogen bond parameters. Quantum theory of atoms in molecules, non-covalent interaction, and symmetry-adapted perturbation theory analyses were performed to reveal the nature of the intermolecular non-covalent interactions. [ABSTRACT FROM AUTHOR]