Center for Computational Molecular Science and Technology, School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, 30332-0400, United States.
J Phys Chem A. 2012 Dec 6;116(48):11920-6. doi: 10.1021/jp305700k. Epub 2012 Nov 27.
π-π interactions are integral to many areas of chemistry, biochemistry, and materials science. Here we use electronic structure theory to analyze how π-π interactions change as the π-systems are curved in model complexes based on coronene and corannulene dimers. Curvature redistributes electronic charge in the π-cloud and creates a dipole moment in these systems, leading to enhanced intermolecular electrostatic interactions in the concave-convex (nested) geometries that are the focus of this work. Curvature of both monomers also has a geometric effect on the interaction by decreasing the average C-C distance between monomers and by increasing the magnitude of both favorable London dispersion interactions and unfavorable exchange-repulsion interactions. Overall, increasing curvature in nested π-π interactions leads to more favorable interaction energies regardless of the native state of the monomers, except at short distances where the most highly curved systems are less favorable as exchange repulsion terms begin to dominate the interaction.
π-π 相互作用是化学、生物化学和材料科学许多领域的基础。在这里，我们使用电子结构理论来分析π-π 相互作用如何随着基于冠状二聚体和corannulene 二聚体的模型复合物中π 体系的弯曲而变化。弯曲在π 云中重新分配电子电荷，并在这些系统中产生偶极矩，导致在我们研究的焦点——凹凸（嵌套）几何形状中增强了分子间的静电相互作用。单体的弯曲也通过降低单体之间的平均 C-C 距离和增加有利的伦敦色散相互作用和不利的交换排斥相互作用的大小对相互作用具有几何效应。总的来说，增加嵌套的 π-π 相互作用的曲率会导致更有利的相互作用能，而不管单体的固有状态如何，除了在短距离处，最弯曲的系统由于交换排斥项开始主导相互作用而变得不太有利。
