Mechanistic insights into the Nb2O5 and niobium phosphate catalyzed in situ condensation of a fluorescent halochromic assembly

[EN] Solid niobium oxides (Nb2O5 center dot nH(2)O) 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 fro...

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Detalles Bibliográficos
Autores: Impellizzeri, Stefania, Simoncelli, Sabrina, Fasciani, Chiara, Hallett-Tapley, Geniece L., Hodgson, Gregory K., Scaiano, Juan C., Marín García, Mª Luisa|||0000-0002-9789-8894
Tipo de recurso: artículo
Fecha de publicación:2015
País:España
Institución:Universitat Politècnica de València (UPV)
Repositorio:RiuNet. Repositorio Institucional de la Universitat Politécnica de Valéncia
Idioma:inglés
OAI Identifier:oai:riunet.upv.es:10251/65016
Acceso en línea:https://riunet.upv.es/handle/10251/65016
Access Level:acceso abierto
Palabra clave:Molecular switches
Intrazeolite photochemistry
Memory
Oxide
Acidity
QUIMICA ORGANICA
QUIMICA ANALITICA
Descripción
Sumario:[EN] Solid niobium oxides (Nb2O5 center dot nH(2)O) 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).