伦敦分散在多环芳香堆叠中的溶剂衰减
Alex Elmi1, Krzysztof M Bąk1, Scott L Cockroft1
1EaStCHEM School of Chemistry, University of Edinburgh, Joseph Black Building, Edinburgh, EH9 3FJ, U.K.
Angewandte Chemie (International ed. in English)
|July 23, 2024
概括
溶剂竞争显著减少了伦敦分散力在分子识别中的影响. 实验表明堆积能量在溶液中很弱,与气相计算不同,突出了利用分散的挑战.
科学领域:
- 物理化学 物理化学
- 超分子化学 超分子化学
- 化学物理 化学物理
背景情况:
- 伦敦分散力在分子识别中至关重要,但受溶剂相互作用的影响.
- 在溶液相分子识别中量化分散的能量贡献是具有挑战性的,因为溶剂竞争.
研究的目的:
- 在分子识别过程中实验性地确定和解构伦敦分散的能量贡献.
- 调查溶剂竞争对堆叠能量的影响,通过不同的接触面积和溶剂特性.
主要方法:
- 利用分子平衡来实验测量烯和烯系统之间的堆叠能量.
- 多样化堆叠接触面积,并使用不同的溶剂 (CS2,CD2Cl2) 来评估溶剂衰减.
- 将实验数据与包括分散项在内的计算计算相关联.
主要成果:
- 溶液中的实验堆叠能量是微弱不利的 (+0.5到+4.6kJ/mol),与气相计算 (-27kJ/mol) 相反.
- 堆叠倾向随着接触面积的增加以及在较低散量极化性的溶剂中增加,这表明分散竞争减少.
- 每单位面积的实验堆叠能量明显低于计算的气相值,在溶液中,值从-0.02到-0.05 kJ/mol/Å2不等.
结论:
- 溶剂竞争强烈减弱,但不会完全取消,在分子识别中分散的能量效益.
- 由于具有竞争力的溶剂相互作用,利用分散力用于溶液中的分子识别仍然是一个重大挑战.
- 了解和量化溶剂对分散的影响对于设计有效的分子识别系统至关重要.
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