Anionic chromogenic chemosensors highly selective for fluoride or cyanide based on 4-(4-Nitrobenzylideneamine)phenol

• Autor(a) principal: Nicoleti,Celso R.
• Data de Publicação: 2012
• Outros Autores: Marini,Vanderléia G., Zimmermann,Lizandra M., Machado,Vanderlei G.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Journal of the Brazilian Chemical Society (Online)
• Texto Completo: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0103-50532012000800011
• topic: anionic chromogenic chemosensor; displacement assay; naked-eye detection; anion sensing; calix[4]pyrrole

4-(4-Nitrobenzylideneamine)phenol was used in two strategies allowing the highly selective detection of F- and CN-. Firstly, the compound in acetonitrile acts as a chromogenic chemosensor based on the idea that more basic anions cause its deprotonation (colorless solution), generating a colored solution containing phenolate. The discrimination of CN- over F- was obtained by adding 1.4% water to acetonitrile: water preferentially solvates F-, leaving the CN- free to deprotonate the compound. Another strategy involved an assay comprised of the competition between phenolate dye and the analyte for calix[4]pyrrole in acetonitrile, a receptor highly selective for F-. Phenolate and calix[4]pyrrole form a hydrogen-bonded complex, which changes the color of the medium. On the addition of various anions, only F- was able to restore the original color corresponding to phenolate in solution due to the fact that the anion dislodges phenolate from the complexation site.