ИСТИНА

The first part of my talk covers the experimental results of studies of molecular ferroelectrics based on pyridinium salts. The para-ferroelectric transition in those compounds is accompanied by the structural phase transformation, resulting in the change of the disorder degree of pyridinium cation and complex oxide-base anions. The pressure effect on such organic materials have been studied by means of neutron and X-ray diffraction, Raman and NMR spectroscopy. The most emphases are directed on pressure induced evolution of ferroelectric phases of such molecular crystals. As logical extension of abovementioned investigations, the recent results of high-pressure studies of complex organic pharmaceutical components are presented. The results of pressure induced polymorphic transitions in resorcinol, chlorpropamide and fluconazole crystals are reported. In the talk the most attention are focused on effect on polymorphic transformations from specific of pressure experiments conditions like as pressurisation ratio, additional temperature treatment, recrystallization process.