Structure and intermolecular interactions in selected binary solutions studied by X-ray methods

• The results of X-ray structural studies of liquid chloroanisole and 10% solutions of chloroanisole in 1,4-dimethylbenzene are presented.
• There was existence of spheres of intermolecular ordering in the studied solutions.
• Measurements were carried out at a temperature of 293 K.
• The presence of short-range ordering reaching about 20 Å in the molecular liquids studied has been proved.
• The packing coefficient of the chloroanisoles accordingly are about 63%.

The results of X-ray structural studies of liquid chloroanisole C6H4OCH3Cl and 10% solutions of chloroanisole in 1,4-dimethylbenzene C8H10 are presented. It is the first paper on an X-ray diffraction study of the liquid solutions of chloroanisole. The X-ray measurements were made at 293 K for the scattering angle range 2ΘΘ varying from 6° to 120°. Averaged scattered X-ray angular distributions I¯(S) were determined. The angular distributions of the intensity of X-ray scattered by 10% solutions of chloroanisole in 1,4-dimethylbenzene were compared to the angular distributions obtained for liquid ortho-, meta- and para  -chloroanisole. The differential radial distribution functions of electron density 4πr2∑j,knK¯j[ρk(r)−ρ0] were numerically found using the Fourier analysis from a modified Warren, Krutter and Morningstar equation. To the maxima of DRDFs, interatomic and intermolecular distances were assigned. The use of short-wave radiation from an X-ray tube with a molybdenum anode permitted determination of the spheres of intermolecular ordering in the studied liquids and their solutions. The experimental results were used to plot models of the most highly probable mutual disposition of the molecules in liquid chloroanisole and their solutions. The benzene rings of two molecules are situated in parallel plane what results in antiparallel setting of the dipole moments of the chloroanisole molecules. X-ray structural analysis was applied to determine the packing coefficients of chloroanisole molecules. The results obtained in this paper confirm the specific structural properties of the solutions studied.