...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Acta Crystallographica, Section B. Structural Science >Experimental and predicted crystal structures of Pigment Red 168 and other dihalogenated anthanthrones
【24h】

Experimental and predicted crystal structures of Pigment Red 168 and other dihalogenated anthanthrones

机译：颜料红168和其他二卤代蒽酮的晶体结构的实验和预测

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

The crystal structures of 4,10-dibromo-anthanthrone (Pigment Red 168; 4,10-dibromo-dibenzo[def,mno]chrysene-6,12-dione), 4,10-dichloro- and 4,10-diiodo-anthanthrone have been determined by single-crystal X-ray analyses. The dibromo and diiodo derivatives crystallize in P2_1/c, Z = 2, the dichloro derivative in P1?, Z = 1. The molecular structures are almost identical and the unit-cell parameters show some similarities for all three compounds, but the crystal structures are neither isotypic to another nor to the unsubstituted anthanthrone, which crystallizes in P2_1/c, Z = 8. In order to explain why the four anthanthrone derivatives have four different crystal structures, lattice-energy minimizations were performed using anisotropic atom-atom model potentials as well as using the semi-classical density sums (SCDS-Pixel) approach. The calculations showed the crystal structures of the dichloro and the diiodo derivatives to be the most stable ones for the corresponding compound; whereas for dibromo-anthanthrone the calculations suggest that the dichloro and diiodo structure types should be more stable than the experimentally observed structure. An experimental search for new polymorphs of dibromo-anthanthrone was carried out, but the experiments were hampered by the remarkable insolubility of the compound. A metastable nanocrystalline second polymorph of the dibromo derivative does exist, but it is not isostructural to the dichloro or diiodo compound. In order to determine the crystal structure of this phase, crystal structure predictions were performed in various space groups, using anisotropic atom-atom potentials. For all low-energy structures, X-ray powder patterns were calculated and compared with the experimental diagram, which consisted of a few broad lines only. It turned out that the crystallinity of this phase was not sufficient to determine which of the calculated structures corresponds to the actual structure of this nanocrystalline polymorph.
机译：4,10-二溴-蒽醌（颜料红168; 4,10-二溴-二苯并[def，mno] chrysene-6,12-dione），4,10-二氯-和4,10-二碘-的晶体结构蒽醌已通过单晶X射线分析确定。二溴和二碘代衍生物在P2_1 / c中结晶，Z = 2，在P1？中，二氯衍生物，Z =1。分子结构几乎相同，并且所有三种化合物的晶胞参数都显示出一些相似性，但是晶体结构在P2_1 / c，Z = 8中结晶时，既没有同种异型，也没有未取代的蒽酮的同型异构体。为了解释为什么四种蒽酮衍生物具有四种不同的晶体结构，使用各向异性原子-原子模型势进行了晶格能最小化以及使用半经典密度和（SCDS-Pixel）方法。计算表明，二氯和二碘代衍生物的晶体结构是相应化合物最稳定的晶体结构。而对于二溴-蒽醌，计算表明二氯和二碘结构类型应比实验观察到的结构更稳定。进行了对新的二溴蒽醌多晶型物的实验研究，但由于该化合物的显着不溶性而使实验受阻。确实存在二溴衍生物的亚稳态纳米晶体第二多晶型物，但它与二氯或二碘化合物不是同构的。为了确定该相的晶体结构，使用各向异性原子-原子电势在各种空间组中进行了晶体结构预测。对于所有低能结构，都计算了X射线粉末模式并将其与仅由几条粗线组成的实验图进行比较。结果表明，该相的结晶度不足以确定所计算的结构中的哪一个与该纳米晶多晶型物的实际结构相对应。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号