Analysis of reaction in Organic Crystals

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In order to analyze the chemical reactions occur in the organic crystals, we have proceeded the structural studies on the various types of solid state reactions by means of X-ray crystal structure analysis, thermalanalysis, theoretical calculation, crystallization and so on. Among the many projects in our group, the development of the diffractometers were especially important for the analysis of the dynamic structural changes in the crystal ttice by the time-resolved diffraction experiments. One of the diffractometers we have developed is the imaging plate two-dimensional diffractometer with temperature control equipment. Another one is a gas-amplification type detector (MSGC) with the area size of 50x50mm and resolution time of 20 msec for one flame of diffraction pattern. 250 flames of diffraction patterns are possible to be accumulated in the memory at once, a time-resolution will be greatly improved by the use of this detector. The practical results for the dynamic structural analysis in the organic crystals are, solid state polymerization in diacethylenylbenzene derivatives, crystalline-state racemization reaction in the cobaloxime complexes with the axial ligand of methyoxycarbonylethyl, racemization of the chiral crystals of cumarin and tartaric acid complexes, phase transition of N- (2,4-dinitrophenyl) -o-anisidine, structure transition of nucleotide crystal coupled with the deletion and addition of crystalline waters, and so on. Moreover, new calculation method was developed in the form of the potential function of ab initio pair-approximation, which is included in the new computer program for public use.