Synthesis, Conformations and Inclusion Properties of Hexahomotrioxacalix[3]arene Triamide Derivatives having Hydrogen-bonding Groups |
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Authors: | Takehiko Yamato Fenglei Zhang |
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Institution: | (1) Department of Applied Chemistry, Faculty of Science and Engineering, Saga University, Honjo-machi 1, Saga-shi, Saga, 840-8502, Japan. |
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Abstract: | The lower rim functionalizedhexahomotrioxacalix3]arene triamide derivatives4a and 4b were synthesized from triol 1by a stepwise reaction. Extraction data for alkalimetal ions, transition metal ions, and alkyl ammoniumions from water into dichloromethane are discussed.Due to the strong intramolecular hydrogen bondingbetween the neighboring NH and CO groups, theiraffinities to metal cations were weakened.cone-4a shows a single selectivity ton-BuNH3
plus while partial-cone-4aalmost has no affinity to cations. The anioncomplexation of cone-4a was studied by1H NMR titration experiments. cone-4abinds halides through the intermolecular hydrogenbonding among the NH hydrogens of amide in a 1 : 1fashion in CDCl3. The association constantscalculated from these changes in chemical shifts ofthe amide protons are Ka = 8520 M-1for Cl-1 and Ka = 1720 M-1 forBr-1. cone-4a shows a preference forCl-1 complexation over Br- complexation. Incontrast, cone-4b has good selectivity andaffinity to Agplus cation. A good Job plot proves1:1 coordination of cone-4b withAgplus cation. The complexation mode of cone-4a with n-BuNH3Cl and cone-4b with AgSO3CF3 were also demonstrated by 1H NMR titration in CDCl3. |
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Keywords: | macrocycles calixarenes hexahomotrioxacalix[3]arenes conformations ionophores host properties molecular recognition ammonium ion extraction |
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