Sulfonamide Molecular Crystals: Structure, Sublimation Thermodynamic Characteristics, Molecular Packing, Hydrogen Bonds Networks

The crystal structures of ten sulfonamides have been determined by X-ray diffraction. On the basis of our previous data, the obtained results and literature data crystal properties including molecular conformational states, packing architecture, and hydrogen bond networks were comparatively analyzed using graph set notations. Conformational flexibility of the bridge connecting two phenyl rings was studied. It was found out that the most frequently occurring graphs for compounds with a single hydrogen bond are infinite chains with four atoms included. The molecular packing architecture of the selected crystals may be conditionally divided into three different groups. The idea underlying such classification is the difference in structure and composition of molecular layers that can be singled out for most packings. The influence of various molecular fragments on crystal lattice energy was analyzed. A correlation between melting points and fragmental molecular interactions in the crystal lattices was obtained. The thermodynamic aspects of the sulfonamide sublimation were studied by determining the temperature dependence of vapor pressure using the transpiration method. A correlation between the Gibbs energy of the sublimation process and the melting points was found. Besides, a regression equation was derived to describe the correlation between the sublimation entropy terms and crystal density data calculated from X-ray diffraction results.