Mechanistic Insights into the Nb2O5 Catalyzed In Situ Condensation of a Fluorescent Halochromic Assembly

Solid niobium oxides (Nb2O5·nH2O) and niobium phosphate were used as heterogeneous acid catalysts to promote the condensation between a switchable oxazine and a fluorescent coumarin in an aprotic solvent. The catalysts were found to promote the generation of an active methylene from the enamine-base...

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Detalles Bibliográficos
Autores: Impellizzeri, Stefania, Simoncelli, Sabrina, Fasciani, Chiara, Marin, M. Luisa, Hallett Tapley, Geniece L., Hodgson, Gregory K., Scaiano, Juan C.
Tipo de recurso: artículo
Estado:Versión publicada
Fecha de publicación:2014
País:Argentina
Institución:Consejo Nacional de Investigaciones Científicas y Técnicas
Repositorio:CONICET Digital (CONICET)
Idioma:inglés
OAI Identifier:oai:ri.conicet.gov.ar:11336/4101
Acceso en línea:http://hdl.handle.net/11336/4101
Access Level:acceso abierto
Palabra clave:Catalysis
Niobium Oxides
Oxazine
Single Molecule
https://purl.org/becyt/ford/1.4
https://purl.org/becyt/ford/1
Descripción
Sumario:Solid niobium oxides (Nb2O5·nH2O) and niobium phosphate were used as heterogeneous acid catalysts to promote the condensation between a switchable oxazine and a fluorescent coumarin in an aprotic solvent. The catalysts were found to promote the generation of an active methylene from the enamine-based portion of the oxazine, which was followed by a nucleophilic attack on the aldehyde functionality of the coumarin reagent. In the resulting system, the emission of the conjugated fluorophore can be observed at 670 nm and, thus, the processes occurring at the catalyst surface can be monitored in real time by total internal reflection fluorescence microscopy (TIRFM).