title: The Interactions between Imidazolium-Based Ionic Liquids and Stable Nitroxide Radical Species: A Theoretical Study.
abstract: In this work, the interactions between imidazolium-based ionic liquids and some stable radicals based on 2,2,6,6-tetramethylpiperidine-1-yloxyl (TEMPO) have been systematically investigated using density functional theory calculations at the level of M06-2x. Several different substitutions, such as hydrogen bonding formation substituent (OH) and ionic substituents (N(CH3)3(+) and OSO3(-)), are presented at the 4-position of the spin probe, which leads to additional hydrogen bonds or ionic interactions between these substitutions and ionic liquids. The interactions in the systems of the radicals containing ionic substitutions with ionic liquids are predicted much stronger than those in the systems of neutral radicals, resulting in a significant reduction of the mobility of ionic radicals in ionic liquids. To further understand the nature of these interactions, the natural bond order, atoms in molecules, noncovalent interaction index, electron density difference, energy decomposition analysis, and charge decomposition analysis schemes were employed. The additional ionic interactions between ionic radicals and counterions in ionic liquids are dominantly contributed from the electrostatic term, while the orbital interaction plays a major role in other interactions. The results reported herein are important to understand radical processes in ionic liquids and will be very useful in the design of task-specific ionic liquids to make the processes more efficient.
authors.affiliation: Key Laboratory for Advanced Materials and School of Chemistry & Molecular Engineering, East China University of Science and Technology , Shanghai 200237, China.
authors.forename: Shaoze
authors.initials: S
authors.lastname: Zhang
authors.affiliation: Drug Discovery and Design Center, Shanghai Institute of Materia Medica, Chinese Academy of Sciences , Shanghai, 201203, China.|University of Chinese Academy of Sciences , No. 19A Yuquan Road, Beijing, 100049, China.
authors.forename: Guimin
authors.initials: G
authors.lastname: Wang
authors.affiliation: Key Laboratory for Advanced Materials and School of Chemistry & Molecular Engineering, East China University of Science and Technology , Shanghai 200237, China.
authors.forename: Yunxiang
authors.initials: Y
authors.lastname: Lu
authors.affiliation: Drug Discovery and Design Center, Shanghai Institute of Materia Medica, Chinese Academy of Sciences , Shanghai, 201203, China.|University of Chinese Academy of Sciences , No. 19A Yuquan Road, Beijing, 100049, China.
authors.forename: Weiliang
authors.initials: W
authors.lastname: Zhu
authors.affiliation: Key Laboratory for Advanced Materials and School of Chemistry & Molecular Engineering, East China University of Science and Technology , Shanghai 200237, China.
authors.forename: Changjun
authors.initials: C
authors.lastname: Peng
authors.affiliation: Key Laboratory for Advanced Materials and School of Chemistry & Molecular Engineering, East China University of Science and Technology , Shanghai 200237, China.
authors.forename: Honglai
authors.initials: H
authors.lastname: Liu