...
  • 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, crystal engineering and materials >The phase transitions of 4-aminopyridine-based indolocarbazoles: twinning, local- and pseudosymmetry
【24h】

The phase transitions of 4-aminopyridine-based indolocarbazoles: twinning, local- and pseudosymmetry

机译：基于4-氨基吡啶的吲哚脱石的相转变：孪生，局部和假寡糖

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 phase transitions and polymorphism of three 4-aminopyridine-based indolocarbazole analogues are analyzed with respect to symmetry relationships and twinning. Seven polymorphs were structurally characterized using singlecrystal diffraction. 5NICz (the indolo[3,2,1-jk]carbazole derivative with the C atom in the 5-position replaced by N) crystallizes as a P2_1/a high-temperature (270 K) polymorph and as a Pca2_1 low-temperature (150 K) polymorph. Even though their space-group symmetry is not related by a group-subgroup relationship, the local symmetries of both belong to the same order-disorder (OD) groupoid family. Both are polytypes of a maximum degree of order and are twinned by point operations of the other polytype. 2NICz (C atom in the 2- position replaced by N) likewise crystallizes in a high-temperature (Pcca, 280 K) polymorph and a low-temperature (P2_1/c, 150 K) polymorph. Here, the spacegroup symmetries are related by a group-subgroup relationship. The lowtemperature phase is twinned by the point operations lost on cooling. The crystal structure of bulk 2,5NICz (N-substitution at the 2- and 5-positions) was unrelated to 2NICz and 5NICz and no phase transition was observed. Isolated single crystals of a different polymorph of 2,5NICz, isotypic with 2NICz, were isolated. However, the analogous phase transition in this case takes place at distinctly higher temperatures (> 300 K).
机译：相对于对称性关系和孪生分析了三种4-氨基吡啶基吲哚咔唑类似物的相转变和多态性。使用单次衍射衍射在结构上表征七种多晶型物。 5nicZ（Indolo [3,2,1-JK]咔唑衍生物在用N代替的5位中的C原子衍生物作为P2_1 / A高温（270k）多晶型物结晶，并作为PCA2_1低温（ 150 k）多晶型物。尽管它们的空间组对称性与组子组关系无关，但两者的局部对称属于相同的订单 - 无序（OD）Galoid系列。两者都是最大订单程度的多型，并通过其他多型点操作孪生。 2-替代的2-替代的2-位的CNOROM）同样在高温（PCCA，280K）多晶型物和低温（P2_1 / C，150K）多晶型物中结晶。这里，空间群体对称性由组子组关系相关。低温阶段由冷却时损失的点操作孪生。体积2,5,2,5（2-和5-位）的晶体结构与2nicZ和5nicZ无关，并且没有观察到相转变。分离出2,5 anci，同种型与2nicz的不同多晶型不同的单一晶体，被隔离。然而，在这种情况下类似相位过渡在明显较高的温度（> 300k）中进行。

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