Analysis of reaction in Organic Crystals

为了分析有机晶体中发生的化学反应，我们采用x射线晶体结构分析、热分析、理论计算、结晶等方法对各类固相反应进行了结构研究。在我们小组的众多项目中，衍射仪的开发对于通过时间分辨衍射实验分析晶体晶格的动态结构变化尤为重要。我们研制的一种衍射仪是带温度控制装置的成像板二维衍射仪。另一种是气体放大型探测器（MSGC），面积为50x50mm，对一个衍射图样火焰的分辨时间为20 msec。在存储器中可以一次积累250个衍射图案的火焰，使用这种探测器将大大提高时间分辨率。有机晶体动态结构分析的实际结果有：二乙基苯衍生物的固相聚合反应、与甲基氧羰基乙基轴向配体的钴胺配合物的结晶态外消旋反应、香豆素与酒石酸配合物的手性晶体外消旋反应、N-（2,4-二硝基苯）-o-茴香胺的相变。核苷酸晶体的结构转变，加上结晶水的缺失和添加，等等。在此基础上，提出了一种新的计算方法——从头开始对逼近的势函数形式，并将其包含在新的公共计算机程序中。

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.