• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Chemistry: A European journal >Chiral supramolecular assemblies of a squaraine dye in solution and thin films: Concentration-, temperature-, and solvent-induced chirality inversion
【24h】

Chiral supramolecular assemblies of a squaraine dye in solution and thin films: Concentration-, temperature-, and solvent-induced chirality inversion

机译：溶液和薄膜中Squaraine染料的手性超分子组件：浓度 - ，温度和溶剂诱导的手性倒置

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 prepared novel cholesterol-appended squaraine dye 1 and model squaraine dye 2 and investigated their aggregation behavior in solution and thin films using photophysical, chiroptical, and microscopic techniques. Investigations on the dependence of aggregation on solvent composition (good/poor, CHCl3/CH3CN) demonstrated that squaraine dye 1 forms two novel H-type chiral supramolecular assemblies with opposite chirality at different good/poor solvent compositions. Model compound 2 formed J-type achiral assemblies under similar conditions. The supramolecular assembly of 1 observed at lower fractions of the poor solvent could be assigned to the thermodynamically stable form, while a kinetically controlled assembly is formed at higher fractions of the poor solvent. This assignment is evidenced by temperature- and concentration-dependent experiments. With increasing temperature, the chirality of the kinetically controlled aggregate was lost and, on cooling, the aggregate with the opposite chirality was formed. On further heating and cooling the aggregates thus formed resulted in no significant changes in chirality, that is they are thermodynamically stable. Similarly, at lower concentrations, the thermodynamically stable form exists, but at higher concentration aggregation was found to proceed with kinetic control. Based on these observations it can be assumed that formation of the kinetically controlled assembly might be largely dependent on the presence of the nonpolar cholesterol moiety as well as the amount of poor solvent present. However, under solvent-free conditions, structurally different aggregates were observed when drop cast from solutions containing monomer, whereas a left-handed CD signal corresponding to the thermodynamically controlled assemblies was observed from pre-aggregated solutions.
机译：我们准备了新型胆固醇附加的Squaraine染料1和模型Squaraine染料2，并使用光药，奇光学和微观技术研究了溶液和薄膜中的聚集行为。对聚集对溶剂组合物（良好/差，CHCL3 / CH3CN）的研究表明，Squaraine染料1形成两种新的H型手性超分子组件，其具有不同良好/差的溶剂组合物的相对血管性。模型化合物2在类似条件下形成了J型成型组件。在较低溶剂的较低级分中观察到的1的超分子组件可以分配给热力学稳定的形式，同时在较差的溶剂的较高级分中形成动力学控制的组件。这种分配通过温度和浓度依赖性实验证明。随着温度的增加，动力学控制的聚集体的手性丢失，在冷却时，形成具有相反的细胞性的聚集体。在进一步加热和冷却的情况下，由此形成的聚集体导致手性无程度的显着变化，即它们是热力学上稳定的。类似地，在较低浓度下，存在热力学稳定的形式，但发现在较高的浓度聚集下，发现进行动力学控制。基于这些观察结果，可以假设动力学控制的组件的形成可能在很大程度上取决于非极性胆固醇部分的存在以及存在的不良溶剂的量。然而，在无溶剂条件下，当从含有单体的溶液浇注时，观察到结构不同的聚集体，而从预聚合的溶液中观察到与热力学控制的组件相对应的左手CD信号。

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