Hydrated cation-π interactions of π-electrons with hydrated Li+, Na+, and K+ cations

Liuhua Mu; Yizhou Yang; Jian Liu; Wei Du; Jige Chen; Guosheng Shi; Haiping Fang

doi:10.1039/d1cp01609a

Hydrated cation-π interactions of π-electrons with hydrated Li⁺, Na⁺, and K⁺ cations

Phys Chem Chem Phys. 2021 Jul 14;23(27):14662-14670. doi: 10.1039/d1cp01609a.

Authors

Liuhua Mu¹, Yizhou Yang², Jian Liu³, Wei Du¹, Jige Chen⁴, Guosheng Shi⁵, Haiping Fang⁶

Affiliations

¹ Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China and University of Chinese Academy of Sciences, Beijing 100049, China.
² Department of Physics, East China University of Science and Technology, Shanghai 200237, China. fanghaiping@sinap.ac.cn.
³ School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China.
⁴ Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China and Shanghai Synchrotron Radiation Facility, Zhangjiang Laboratory, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai, 201204, China.
⁵ Shanghai Applied Radiation Institute and State Key Lab. Advanced Special Steel, Shanghai University, Shanghai 200444, China. gsshi@shu.edu.cn.
⁶ Department of Physics, East China University of Science and Technology, Shanghai 200237, China. fanghaiping@sinap.ac.cn and Shanghai Synchrotron Radiation Facility, Zhangjiang Laboratory, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai, 201204, China.

PMID: 34213518
DOI: 10.1039/d1cp01609a

Abstract

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.