Conformational control of electron-rich calix[6]arene skeleton by paraquat recognition

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• 作者：Shigehisa Akine^a ; ^b ; ^{akine@chem.tsukuba.ac.jp} ; Daisuke Kusama^a ; Tatsuya Nabeshima^a ; ^b ; ^{nabesima@chem.tsukuba.ac.jp}
• 关键词：Calixarene ; Molecular recognition ; Host&ndash ; guest complex ; Conformational isomers ; Structural conversion
• 刊名：Tetrahedron Letters
• 出版年：2013
• 出版时间：16 January, 2013
• 年：2013
• 卷：54
• 期：3
• 页码：205-209
• 全文大小：467 K

文摘

Calix[6]arene derivatives having electron-donating groups were designed and synthesized for the recognition of electron-deficient organic guests. These compounds exhibited relatively well-resolved ¹H NMR spectra while most calix[6]arene derivatives reported previously showed broad spectra. The ¹H NMR spectra clearly indicated that the studied calix[6]arene derivatives adopted a 1,2,3-alternate conformation as the dominant conformation. The hydroxy derivative formed a host-guest complex with paraquat molecule, in which the calix[6]arene framework exclusively adopted a cone conformation. Thus, an efficient conformational conversion from the 1,2,3-alternate to the cone conformation took place upon the host-guest complexation.