Novel Spiro-Derivatives of 1,3-Thiazine Molecular Crystals: Structural and Thermodynamic Aspects

Crystal structures of 10 spiro-derivatives of 1,3-thiazine were determined by X-ray diffraction technique. Molecular conformational states, packing architecture, and hydrogen bond networks were studied using graph set notations. Selected compounds were grouped within two classes with chains and dimer crystal structure organization. The sublimation thermodynamic aspects of the spiro-derivatives of 1,3-thiazine were investigated via temperature dependence of vapor pressure using the transpiration method. Thermophysical study of fusion processes of the molecular crystals was carried out and relationships between thermodynamic characteristics of sublimation (fusion) processes and crystal structure parameters were obtained. The influence of various molecular fragments on packing crystal energy was analyzed.