...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Crystal growth & design >Polymorphic Crystallization and Thermodynamic Phase Transition between the Polymorphs of a Photochromic Diarylethene
【24h】

Polymorphic Crystallization and Thermodynamic Phase Transition between the Polymorphs of a Photochromic Diarylethene

机译：光致变色二芳基乙烯的多晶型物之间的多晶型结晶和热力学相变

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

We synthesized a photochromic diarylethene, 1,2-bis(2-methyl-5-(4-hexyloxyphenyl)-3-thienyl)perfluorocyclopentene (1a), and found that it has two types of crystals, a needle-like alpha-crystal and a plate-like beta-crystal. From X-ray crystallographic analysis, the space groups of the alpha- and beta-crystals were determined to be P1 and C2/c, respectively. The molecular conformation and packing of two crystal forms are quite different. The alpha- and beta-crystals can be obtained individually by recrystallization from acetone at different temperatures. The solvent-mediated phase transition from the a-crystal to the beta-crystal was found to occur in the acetone solution at room temperature. Moreover, the thermodynamic phase transition from alpha-form to beta-form was found to take place above 88 degrees C, as confirmed by differential scanning calorimetry measurement, optical microscopic observation under crossed Nicols, and powder X-ray diffraction measurement. The phase transition from alpha-form to beta-form was also observed at 78 degrees C by photochromic reaction of 1a, and the phase transition proceeded from the UV irradiated part to the nonirradiated part.
机译：我们合成了一种光致变色的二芳基乙烯，1,2-双（2-甲基-5-（4-己氧基氧基苯基）-3-噻吩基）全氟环戊烯（1a），发现它具有两种晶体，一种针状的α晶体。和板状的β晶体。通过X射线晶体学分析，确定α和β晶体的空间群分别为P1和C2 / c。两种晶体形式的分子构象和堆积非常不同。通过在不同温度下从丙酮中重结晶，可以分别获得α和β晶体。发现在室温下在丙酮溶液中发生溶剂介导的从α-晶体到β-晶体的相变。此外，发现由α-型向β-型的热力学相变发生在88℃以上，这通过差示扫描量热法测量，在交叉尼科耳斯下的光学显微镜观察以及粉末X射线衍射测量来证实。通过1a的光致变色反应，在78℃下也观察到了从α形式到β形式的相变，并且相变从UV照射部分向非照射部分进行。

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