Cyclophane-shaped ionic liquids with planar chirality: effects of bridge unit on thermal properties and chirality-recognition ability

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• 作者：Tomohisa Noguchi^a ; Chunji Li^a ; Daisuke Sasaki^a ; Kuniyo Yamada^b ; Kazuhiko Saigo^c ; Yasuhiro Ishida^b ; ^{y-ishida@riken.jp" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Chirality recognition ; Cyclophanes ; Imidazolium salts ; Ionic liquids ; Planar chirality
• 刊名：Tetrahedron
• 出版年：2016
• 出版时间：17 March 2016
• 年：2016
• 卷：72
• 期：11
• 页码：1493-1504
• 全文大小：1080 K

文摘

Six types of cyclophane-shaped imidazolium salts with planar chirality were synthesized in stereopure forms. The cyclophanes were based on a 2-methylimidazolium unit, the two nitrogen atoms of which were connected by a bridge unit with systematically changed structure. Most salts of the chiral cations with fluorinated imide/amide counter anions existed as ionic liquids from −30 °C to >270 °C, the properties and chirality-recognition ability of which were thoroughly investigated. The imidazolium cation with a hydroxymethyl side chain showed the best chirality-recognition ability and was successfully applied as an NMR enantio-differentiating agent and a chiral stationary phase for gas chromatography.