合成,结构和异常扭曲的五角星的分辨率
Jun Lu1, Douglas M Ho, Nancy J Vogelaar
1Department of Chemistry, Princeton University, Princeton, NJ 08544, USA.
Journal of the American Chemical Society
|December 21, 2006
概括
高度扭曲的多环芳,9,10,11,20,21,22-hexaphenyltetrabenzo[a,c,l,n]pentacene (2) 和其二甲基衍生物 (2m),进行了合成和表征. 这些化合物表现出极端的扭曲和高光学活性,在室温下慢慢的种族化.
科学领域:
- 有机化学 有机化学
- 材料科学 材料科学 材料科学
- 超分子化学 超分子化学
背景情况:
- 多环芳 (PAHs) 是有机电子学和材料科学中的基本构件.
- 在PAH中实现高度的分子扭曲是具有挑战性的,但对于调整它们的光物理和电子性质至关重要.
- 在扭曲的PAH中理解结构属性关系可以导致新的功能材料.
研究的目的:
- 为了合成新型,高度扭曲的多环芳,特别是9,10,11,20,21,22-hexaphenyltetrabenzo[a,c,l,n]pentacene (2) 和其二甲基衍生物 (2m).
- 描述这些合成化合物的结构,光物理和手术性能.
- 研究种族化动态,并将实验结果与计算预测进行比较.
主要方法:
- 通过1,3-二二[9,10-c]与比沙林等效物的反应合成,然后进行脱氧.
- 用X射线晶体学来详细确定扭曲分子结构的结构.
- 基拉尔色谱用于反体分辨率和特定旋转的测量.
- 变量温度的种族化研究和计算建模.
主要成果:
- 成功合成了9,10,11,20,21,22-hexaphenyltetrabenzo[a,c,l,n]pentacene (2) 和其二甲基衍生物 (2m),它们是具有强色光的明亮红色固体.
- X射线结构显示这些化合物是已知的最高度扭曲的多环芳化合物,端到端的扭曲高达144度.
- 纯的反体表现出极高的特定旋转 ([alpha]D = 7400度为2,5600度为2m),但在室温下经历缓慢的种族化 (DeltaG++rac = 24 kcal/mol).
- 实验数据与有关几何学和种族化障碍的计算研究非常一致.
结论:
- 这项研究提出了一种具有显著结构和手术特性的高度扭曲PAHs的新类.
- 极端扭曲和高光学活性表明了PAH设计的新前沿.
- 观察到的种族化屏障为这些复杂分子的动态行为提供了洞察力.
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