Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China and University of Chinese Academy of Sciences, Beijing 100049, China.
Department of Physics, East China University of Science and Technology, Shanghai 200237, China.
Phys Chem Chem Phys. 2021 Jul 14;23(27):14662-14670. doi: 10.1039/d1cp01609a.
Cation-π interactions are essential for many chemical, biological, and material processes, and these processes usually involve an aqueous salt solution. However, there is still a lack of a full understanding of the hydrated cation-π interactions between the hydrated cations and the aromatic ring structures on the molecular level. Here, we report a molecular picture of hydrated cation-π interactions, by using the calculations of density functional theory (DFT). Specifically, the graphene sheet can distort the hydration shell of the hydrated K+ to interact with K+ directly, which is hereafter called water-cation-π interactions. In contrast, the hydration shell of the hydrated Li+ is quite stable and the graphene sheet interacts with Li+ indirectly, mediated by water molecules, which we hereafter call the cation-water-π interactions. The behavior of hydrated cations adsorbed on a graphene surface is mainly attributed to the competition between the cation-π interactions and hydration effects. These findings provide valuable details of the structures and the adsorption energy of hydrated cations adsorbed onto the graphene surface.
阳离子-π 相互作用对于许多化学、生物和材料过程都是至关重要的，而这些过程通常涉及含有盐的水溶液。然而，我们仍然缺乏对水合阳离子与芳香环结构之间在分子水平上的水合阳离子-π 相互作用的全面理解。在这里，我们通过使用密度泛函理论（DFT）的计算，报告了水合阳离子-π 相互作用的分子图像。具体来说，石墨烯片可以扭曲水合 K+的水合壳，使其直接与 K+相互作用，我们将其称为水-阳离子-π 相互作用。相比之下，水合 Li+的水合壳非常稳定，石墨烯片通过水分子间接地与 Li+相互作用，我们将其称为阳离子-水-π 相互作用。吸附在石墨烯表面上的水合阳离子的行为主要归因于阳离子-π 相互作用和水合作用之间的竞争。这些发现提供了有关吸附在石墨烯表面上水合阳离子的结构和吸附能的有价值的细节。
