双极诱导的多态形式的转基因-2-基环乙碳酸与几乎相同的单元细胞
Alajos Kálmán1, László Fábián, Gyula Argay
1Institute of Chemistry, Chemical Research Center, Hungarian Academy of Sciences, P.O. Box 17, Budapest 114, H-1525, Hungary. akalman@chemres.hu
Journal of the American Chemical Society
|January 8, 2003
概括
跨-2-基环乙碳酸的多态体表现出微妙的结构差异,导致独特的晶体堆叠和二极管安排. 纯I型晶体不能被隔离,因为它们与II型晶体相互透.
科学领域:
- 晶体学 晶体学是指结晶学.
- 固态化学 固态化学
背景情况:
- 有机分子中的多态性在材料科学中提出了挑战.
- 了解晶体包装对于预测材料特性至关重要.
研究的目的:
- 为了研究跨-2-基环乙碳酸的多态体之间的结构差异.
- 为了阐明晶体结构和双极行为之间的关系.
主要方法:
- 用X射线晶体学来确定晶体结构.
- 空间组和格子参数的分析.
- 研究结网和分子结构的研究.
主要成果:
- 对于两个多态体,相同的格子参数,模仿等态.
- 不同的空间组 (形式II的Pna21,形式I的Pn21a) 决定了晶体包装.
- 形式II表现出反平行层堆叠,取消单元细胞二极体.
- 形式I显示平行层堆叠,与反平行域取消双极.
- 在域边界观察到的形式I中的形式II的交叉生长.
结论:
- 由于与II形式的联合结晶,不能分离出trans-2-hydroxycycloheptanecarboxylic酸的纯I形式.
- 在晶体之间,II形式与I形式的比例会有所不同,这会影响宏观性质.
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