How important are dispersion interactions to the strength of aromatic stacking interactions in solution?
How important are dispersion interactions to the strength of aromatic stacking interactions in solution?
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DOI：
10.1039/c5sc01370d
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发表时间：
2015-01-01
期刊：
影响因子：
8.4
通讯作者：
Shimizu, Ken D.
中科院分区：
文献类型：
--
作者：
Hwang, Jungwun;Dial, Brent E.;Shimizu, Ken D.
在这项研究中，使用一个小分子模型系统实验评估了伦敦色散力对溶液中芳香族堆积相互作用强度的贡献。设计了一系列分子扭转天平，通过构象平衡测量分子内的堆积相互作用。为了探索分散项的重要性，系统地增加了其中一个芳香族表面(苯、萘、菲、联苯、二苯乙烯和二苯乙炔)的大小和极化率。在校正了疏溶剂、连接基和静电取代基的影响后，发现在溶液中由极化率引起的变化比在真空中的类似计算研究要小一个数量级。这些结果表明，在溶液中，色散项是芳香族堆积相互作用的一小部分，而不是在真空中起主导作用。
In this study, the contributions of London dispersion forces to the strength of aromatic stacking interactions in solution were experimentally assessed using a small molecule model system. A series of molecular torsion balances were designed to measure an intramolecular stacking interaction via a conformational equilibrium. To probe the importance of the dispersion term, the size and polarizability of one of the aromatic surfaces were systematically increased (benzene, naphthalene, phenanthrene, biphenyl, diphenylethene, and diphenylacetylene). After correcting for solvophobic, linker, and electrostatic substituent effects, the variations due to polarizability were found to be an order of magnitude smaller in solution than in comparison to analogous computational studies in vacuo. These results suggest that in solution the dispersion term is a small component of the aromatic stacking interaction in contrast to their dominant role in vacuo.