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- Title
Ditopic receptors of hexaamide derivatives derived from hexahomotrioxacalix[3]arene triacetic acid.
- Authors
Yamato, Takehiko; Rahman, Shofiur; Zeng Xi; Kitajima, Fumika; Jeong Tae Gil
- Abstract
The lower rim functionalized hexahomotrioxacalix[3]arene hexaamide 7 having an amino acid moiety with cone conformation was synthesized from triol 1 by a stepwise reaction. The different extractability for alkali metal ions, transition metal ions, and alkylammonium ions from water into dichloromethane was discussed. Owing to the strong intramolecular hydrogen bond between the neighboring NH and CO groups in hexaamide 7, its affinity to metal cations was weakened. Hexaamide 7 shows a single selectivity to n-BuNH3+. The anion complexation of hexaamide 7 was also studied by 1H NMR titration experiments. Hexaamide 7 binds halides through the intermolecular hydrogen bond among the NH hydrogens of the amide in a 1:1 fashion in CDCl3. Thus, hexaamide 7 serves as a heteroditopic receptor that can complex with halides (Cl–, Br–) and n-BuNH3+ at the same time. The association constants calculated from the chemical shift changes of the amide protons are Ka = 536 ± 32 (mol/L)–1 for Cl– and Ka = 230 ± 17 (mol/L)–1 for Br–.
- Subjects
AROMATIC compounds; IONS; ELECTRONS; ORGANIC compounds; ORGANIC acids; HYDROGEN bonding; PHYSICAL &; theoretical chemistry; MOLECULAR association
- Publication
Canadian Journal of Chemistry, 2006, Vol 84, Issue 1, p58
- ISSN
0008-4042
- Publication type
Article
- DOI
10.1139/V05-260