中国科学院化学所吴海臣团队报道了纳米笼内的单分子交换揭示π -π相互作用的起源。相关研究成果发表在2024年3月27日出版的《美国化学会杂志》。

芳香环之间的吸引相互作用，也称为π–π相互作用，已经被广泛使用了几十年。然而，由于难以通过实验测量π-系统之间的弱相互作用，π–π相互作用的起源仍然存在争议。

该文中，研究人员构建了一个复杂的系统，通过蛋白质纳米孔内的分子交换过程，准确比较苯丙氨酸衍生物之间的π–π相互作用的强度。基于结合强度的定量比较，发现在大多数情况下，π–π相互作用主要由色散引力驱动，静电相互作用起次要作用并趋于排斥。然而，在电子效应特别强的情况下，静电感应可能超过分散力，成为π-系统之间相互作用的主要驱动力。

该项研究的结果不仅加深了我们对π-堆积的理解，而且对π–π相互作用发挥关键作用的领域也有潜在的意义。

附：英文原文

Title: Single-Molecule Exchange inside a Nanocage Provides Insights into the Origin of π–π Interactions

Author: Wenying Hao, Bingyuan Guo, Jianchuan Liu, Qianyuan Ren, Shumu Li, Qian Li, Ke Zhou, Lei Liu, Hai-Chen Wu

Issue&Volume: March 27, 2024

Abstract: The attractive interactions between aromatic rings, also known as π–π interactions, have been widely used for decades. However, the origin of π–π interactions remains controversial due to the difficulties in experimentally measuring the weak interactions between π-systems. Here, we construct an elaborate system to accurately compare the strength of the π–π interactions between phenylalanine derivatives via molecular exchange processes inside a protein nanopore. Based on quantitative comparison of binding strength, we find that in most cases, the π–π interaction is primarily driven by dispersive attraction, with the electrostatic interaction playing a secondary role and tending to be repulsive. However, in cases where electronic effects are particularly strong, electrostatic induction may exceed dispersion forces to become the primary driving force for interactions between π-systems. The results of this study not only deepen our understanding of π-stacking but also have potential implications in areas where π–π interactions play a crucial role.

DOI: 10.1021/jacs.4c03159

Source: https://pubs.acs.org/doi/abs/10.1021/jacs.4c03159