Enhanced thermodynamic and kinetic stability of calix[4]arene dimers locked in the cone conformation.
J Org Chem
; 69(18): 6115-20, 2004 Sep 03.
Article
em En
| MEDLINE
| ID: mdl-15373497
ABSTRACT
Wide rim tetraurea derivatives (2a,b) have been prepared from a calix[4]arene rigidified in the cone conformation by two diethyleneglycol ether bridges between adjacent oxygens. In comparison to the analogous tetraurea derivatives (3a,b) of a tetrapentoxy calix[4]arene, 2a,b show an increased thermodynamic stability in mixtures of CDCl(3) and DMSO-d(6). Their kinetic stability as expressed by the rate of guest exchange (benzene or cyclohexane against the solvent benzene-d(6)) is also strongly increased by factors of 30-38. Noticeable differences for the inclusion of selected guests are found.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Fenóis
/
Ureia
/
Calixarenos
Idioma:
En
Ano de publicação:
2004
Tipo de documento:
Article