| Autor: |
Guillon, Jean, Sonnet, Pascal, Malval, Jean-Pierre, Massip, Stéphane, Gosse, Isabelle, Léger, Jean-Michel, Lapouyade, René, Rochette, Jacques, Monti, Jean-Pierre, Jarry, Christian |
| Předmět: |
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| Zdroj: |
Supramolecular Chemistry; Oct2002, Vol. 14 Issue 5, p437, 15p |
| Abstrakt: |
The preparation of new 25,27-bis(alkyloxy)calix[4]arenes-crown-6 in the cone, partial-cone and 1,3-alternate conformation is reported. We have also investigated the alkylation of the cone monoalkylated calix[4]arene-crown-6 achieved using Cs 2 CO 3 . This reaction afforded a mixture of cone and partial-cone calix[4]arenes-crown-6 having an alkyl chain anti or syn to the polyether ring. Conformations have been probed using 1 H, 13 C, 2D-NMR and NOESY analysis, and using X-ray crystallography. Extraction experiments using a two-phase solvent method involving cesium picrate were performed for these newly synthesized conformers. They reveal and confirm the strong preference for the 1,3-alternate conformers. The affinity of 1,3-alternate calixarenes for Cs + has been assessed by complexation measurements (log β ) using a spectrophotometric technique. No significant Cs + extraction difference was observed in relation to the nature of the alkyl chains on the aromatic rings. 1 H NMR studies of the 1,3-alternate calixarene Cs + complexes confirms the cation's spacial position between the two aromatic rings, due to cation-π interactions. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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