Synthesis and Characterization of Imidazolium Salts with the Weakly Coordinating [B(C₆F₅)₄]^– Anion

Abstract

Graphical Abstract Synthesis and Characterization of Imidazolium Salts with the Weakly Coordinating [B(C6F5)4]– Anion

Cationic polymerization of isobutylene by AlCl3 in n‐hexane and toluene at mild temperatures

“…According to the vinyl contents shown in Table 2, the presence of ether strongly contributed to the increase of the vinyl content. Dibutyl ether in association with AlCl 3 favors the increase of the exo‐olefin terminal groups, as expected, due to good stabilization of the carbenium ions 32,46 . Moreover, the ether plays an important role in chain transfer for the formation of exo‐olefin groups because the terminal double bonds derived from the chain reaction generate the protonation and the propagation of the monomer 15 .…”

“…The vinyl contents shown in Table 3 for polymerizations performed with the initial temperature of 30°C displayed a similar behavior to those described in Table 2 for reactions conducted with the initial temperature of 10°C. As the formation of the catalyst complex between ether and AlCl 3 stabilizes the carbenium ions, the vinyl contents increase and polymer yield decreases in the presence of ether, 32,46 as clearly shown in Table 3. The highest vinyl content (around 35 mol%) was obtained in the presence of mixtures of n ‐hexane and toluene, and co‐initiated by ether and water.…”

“…Dibutyl ether in association with AlCl 3 favors the increase of the exo-olefin terminal groups, as expected, due to good stabilization of the carbenium ions. 32,46 Moreover, the ether plays an important role in chain transfer for the formation of exo-olefin groups because the terminal double bonds derived from the chain reaction generate the protonation and the propagation of the monomer. 15 The maximum vinyl content (around 30%) was obtained when toluene was the solvent and the reaction was initiated by ether, with or without water (R7 and R8).…”

Ion Pairs of Weakly Coordinating Cations and Anions: Synthesis and Application for Sulfide to Sulfoxide Oxidations

“…Recently it has been demonstrated that a reduced ion pairing interaction leads to an increased nucleophilicity of perrhenate [59,60] and polyoxomolybdate [61,62] anions, rendering anion-based activation of H 2 O 2 and oxidation of olefins and sulfides possible. Additionally, the synthesis of imidazolium salts containing the [B(C 6 F 5 ) 4 ] − anion showing a weak cation-anion interaction was reported [63]. The tetrafluoroborate anion is also capable of activating hydrogen peroxide by forming hydrogen bonds, which leads to the oxidation of sulfides [65].…”