Allosteric bindings of thiacalix[4]arene-based receptors with 1,3-alternate conformation having two different side arms

  • Carol Pérez-Casas
  • Shofiur Rahman
  • Nazneen Begum
  • Zeng Xi
  • Takehiko Yamato
Original Article


A novel ditopic receptor possessing two complexation sites such as crown ether and 2-pyridylmethyl groups bearing 1,3-alternate conformation based on thiacalix[4]arene was prepared. The binding behaviors with Li+ and Ag+ have been examined by 1H NMR titration experiment. The exclusive formation of mononuclear complexes of 1,3-alternate-5 with Li+ and Ag+ was observed even though the formation of the heterogeneous dinuclear complexes was expected. The decomplexation of Li+ from the crown moiety of 1:1 complex 1,3-alternate-5⊃Li+ to form the Ag+⊂1,3-alternate-5 complex by addition of AgSO3CF3 clearly shows that pyridyl moiety works as an efficient switch-off of the recognition ability of the crown moiety. We have also developed the construction of hydrogen-bonding self-assembly heterodimeric systems based on bis(4-pyridyl) and dicarboxylic acid thiacalix[4]arene derivatives in 1,3-alternate conformation. Their supramolecular behaviors are studied by 1H NMR titration experiments with K+ and Ag+ ions. Although the values of the dimerization constants are relatively small, the stability of the dimers is strong enough to overcome only small conformational changes upon complex formation.


Thiacalix[4]arenas Crownethers Conformation Metal complexation Allosteric effect Hydrogen bond Self-assembly Heterodimeric systems 



We would like to thank the OTEC at Saga University for financial support.


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Copyright information

© Springer Science+Business Media B.V. 2007

Authors and Affiliations

  • Carol Pérez-Casas
    • 1
  • Shofiur Rahman
    • 1
  • Nazneen Begum
    • 1
  • Zeng Xi
    • 1
  • Takehiko Yamato
    • 1
  1. 1.Department of Applied Chemistry, Faculty of Science and EngineeringSaga UniversitySaga-shiJapan

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