Real‐space crystal structure solution. Crystal and molecular structure of laminarabiose octaacetate, C28H38O19
Real‐space crystal structure solution. Crystal and molecular structure of laminarabiose octaacetate, C28H38O19
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层状二糖八乙酸酯 C28H38O19 的晶体和分子结构的实空间晶体结构溶液。
DOI：
10.1107/s0108768185002099
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发表时间：
1985
期刊：
影响因子：
--
通讯作者：
V. Tran
中科院分区：
文献类型：
--
作者：
S. Pérez;C. Vergelati;V. Tran
在分子内和分子间堆积能完全最小化的基础上对晶体结构的阐明已应用于层状阿拉伯糖八乙酸酯。【水晶数据：Mr = 678.6，正交晶系，P212~21，a = 10.379（2），B = 22.943（7），c=14.599（4）A，Z=4，V=3476.4~ 3，Din= 1.30（1），Dx = 1.297 Mgm-3，h（Cu Ka）= 1.54178 A，/z（Cu Ka）=0.91 mm -3，F（000）= 1432，室温，对于1660个观察到的独立反射，最终R = 0.095。两个D-葡萄糖残基具有4C-吡喃糖构象，并以fl-（1 ~ 3）连接。糖苷键的构象角β和β分别为-81.1 °和134.8 °。目前的工作建立在一个明确的方式构象分析理论应用于阐明晶体结构的基础。看来，在晶体中的分子间的相互作用，可以很好地近似处理与分子内的势函数。当与适当的X射线数据相结合时，可以在没有高度精确的势函数的情况下推导出晶体构象。与聚合物晶体学中所面临的问题相比，在聚合物晶体学中，填充参数的数量减少了，找到一个好的起点可能是与所提出的方法相关的基本困难。一旦一个合理的位置 * propre-du CNRS，associate 6 ~ l 'Universit 6 Scientific et M6 dicale de Grenoble，France. f现住址：Aluminatoire de Stockage et de Conservation des Den 6 es Alimentaires，INRA，Centre de Recherche de南特，Chemin de la G6 raudi 6 re，44072南特，法国。已经发现的分子，最小化程序允许一个处理一个合理数量的参数，但只产生几个可能的结构模型。在这个阶段，最好的填充模型必须针对X射线结构振幅进行检查。
The elucidation of a crystal structure on the basis of complete minimization of intramolecular and intermolecular energy of packing has been applied to laminarabiose octaacetate. [Crystal data: Mr = 678.6, orthorhombic, P212~21, a = 10.379 (2), b = 22.943 (7), c=14.599 (4) A, Z=4, V=3476.4~ 3, Din= 1.30 (1), Dx = 1.297 Mgm -3, h(Cu Ka)= 1.54178 A, /z(Cu Ka)=0.91 mm -~, F(000)= 1432, room temperature, final R = 0.095 for 1660 observed independent reflexions.] The two D-glucose residues have the 4C~ pyranose conformation and are fl-(1 ~ 3) linked. The conformational angles ~p and ~ at the glycosidic linkage have the values -81.1 and 134.8 ° respectively. The present work establishes in an unambiguous manner the foundation of conformational analysis theory applied to the elucidation of crystal structures. It appears that intermolecular interactions in the crystal can be treated in good approximation with the intramolecular potential functions. When coupled with appropriate X-ray data, crystalline conformations may be deduced without highly refined potential functions. As compared to what is faced in polymer crystallography, where the number of packing parameters is reduced, finding a good starting point may represent the essential difficulty associated with the proposed methodology. Once a reasonable location * Laboratoire Propre du CNRS, associ6 ~ l'Universit6 Scientifique et M6dicale de Grenoble, France. f Present address: Laboratoire de Stockage et de Conservation des Denr6es Alimentaires, INRA, Centre de Recherche de Nantes, Chemin de la G6raudi6re, 44072 Nantes, France. has been found for the molecule, the minimization procedure allows one to handle a reasonable number of parameters and yet yields only a few possible structural models. At this stage, the best packing models have to be checked against X-ray structure amplitudes.