Mechanism of Nucleophilic Fluorination Facilitated by a Pyrene‐tagged Ionic Liquids: Synergistic Effects of Pyrene–Metal Cation π‐Interactions

Bulletin of the Korean Chemical Society

Byeong Ki Min¹  SungSik Lee² 

[1] Department of Applied Chemistry Kyung Hee University Gyeonggi 17104 Republic of Korea;Department of Chemistry and Chemical Engineering Inha University Incheon 402751 Republic of Korea

关键词: Mechanism;    Fluorination;    Pyrene;    Ionic Liquid 1‐;    Butyl‐;    3‐;    methylimidazolium;   

DOI  :  10.1002/bkcs.11548

学科分类：化学（综合）

来源: Korean Chemical Society

【 摘 要 】

We examine the mechanism of SN2 fluorination promoted by a pyrene‐tagged ionic liquid (PIL). Comparison is made for contact ion‐pair (CIP) vs. solvent‐separated ion‐pair (SSIP) mechanism by calculating the Gibbs free energies of pre‐reaction complexes and Gibbs free energies of activation G‡ for both processes. We find that the CIP mechanism is preferred for [PIL + MF + C3H7OMs] (M = Cs, K) system. SN2 fluorination of the [1‐Butyl‐3‐methylimidazolium (bmim)‐CsF] system is also studied in order to estimate the efficacy of PIL vs. more conventional ionic liquid [bmim][OMs]. The better promotion of the reaction by PIL is attributed to π interactions between the metal cation and pyrene, giving G‡ that is smaller (by approximately 1.3 kcal/mol) than that for the [bmim‐CsF] system, in excellent agreement with experimental observations.

【 授权许可】

Unknown