Abstract
An unsymmetrical calix[4]-bis-crown ether having both conventional crown-6 and dibenzocrown-6 rings in a fixed 1,3-alternate conformation was synthesized with good yield by the reaction of a monocyclic calix[4]crown-6 with dibenzodimesylate in the presence of cesium carbonate. The cesium ion selectivity among alkali metal ions increased compared to symmetrical calix[4]-bis-crown-6. The solid state structure of the ligand-cesium complex illustrates a 1:2 complex ratio. On the contrary, in solution, e.g., extraction equilibrium and 1 H NMR experiment gave a 1:1 complex ratio. From the result of the chemical shift change upon metal ion complex, the cesium ion seems to prefer the dibenzocrown loop to the conventional crown-6 ring.
Original language | English |
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Pages (from-to) | 183-187 |
Number of pages | 5 |
Journal | Journal of Inclusion Phenomena |
Volume | 40 |
Issue number | 3 |
DOIs | |
Publication status | Published - 2001 Jul |
Externally published | Yes |
Keywords
- Calix[4]-bis-crown
- Calixarene
- Complexation
- Crown ether
- Crystal structure
ASJC Scopus subject areas
- Food Science
- Chemistry(all)
- Condensed Matter Physics