Estudio mecanístico de la reacción fotoquímica de complejos tricarbonilos de renio generadores de oxígeno singlete o liberadores de monóxido de carbono
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2021
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es
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Universidad Andrés Bello
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Licencia CC
Licencia CC
Resumen
Los compuestos de renio Re(I) con ligandos diiminas han concitado especial
interés debido a la gran cantidad de aplicaciones que se han ido descubriendo
durante las últimas décadas, tanto en aplicaciones ambientales, como medicinales.
Existe gran cantidad de información acerca del comportamiento fotofísico de
complejos de Re(I) durante los últimos años, sin embargo se encuentran pocos
reportes de generación de fotoproductos o de especies reactivas, lo cual podría
tener aplicaciones prácticas en síntesis, remediación o Terapia Fotodinámica
(PDT). Complejos de Re(I) con ligando híbrido P,N-bidentado como el 2-piridil difenilfosfina, se han preparado con propósitos sintéticos o catalíticos. Nuestro
grupo recientemente sintetizó y caracterizó las propiedades fotofísicas de complejos
tricarbonilos de Re(I) con ligandos fosfina-imina: [P,N-{(C6H5)2(C5H4N)P}Re(CO)3Br]
(RePNBr), [P,N-{(C6H5)2(C5H4N)P}Re(CO)3(O-CF3SO3)] (RePNTfO) and [P,N-
{(C6H5)2(C5H4N)NHP}Re(CO)3Br] (RePNNBr) (Esquema 1), pero su
comportamiento fotoquímico no había sido explorado.
Por lo anterior es de suma importancia conocer cuál es su mecanismo de
fotodegradación, ya que que abre un camino para el entendimiento de su
comportamiento y la mejor aplicación posterior de sus propiedades.
Para lograr entender este mecanismo se utilizó el estudio fotoquímico, irradiando
los compuestos y por medio del cambio en sus espectros de absorción, obtener
parámetros termodinámicos que nos orienten a dilucidar como ocurre este proceso
fotodegradativo. Los resultados de la entropía del complejo activado nos llevan a
proponer un camino en donde se produce una fotoisomerización del complejo y/o
una fotodimerización.
Rhenium compounds have attracted special interest due to the large number of applications that have been discovered the last decades, both in environmental and medicinal applications. A great amount of research related to ReI -diimine complexes has been developed during the last decade, however the photoproduct or reactive species generation, remain mostly unexplored, which could also have potential use in practical applications such as synthesis, remediation or photodynamic therapy (PDT). Rhenium(I) complexes with hybrid P,N-bidentate ligands, like 2-pyridyl diphenylphosphine, have been prepared for synthetic or catalytic purposes. Our group have recently reported the syntheses and photophysical properties of rhenium(I) tricarbonyl complexes with a phosphine-imine ligand: [P,N- {(C6H5)2(C5H4N)P}Re(CO)3Br] (RePNBr), [P,N-{(C6H5)2(C5H4N)P}Re(CO)3(O CF3SO3)] (RePNTfO) and [P,N-{(C6H5)2(C5H4N)NHP}Re(CO)3Br] (RePNNBr) (Scheme 1), but their photochemical behavior were unexplored. Therefore, it is very important to know how its photodegradation mechanism is going on, which opens a way to be able to understand its performance and the subsequent improvement of these applications. In order to understand this mechanism, photochemical tools were used, such as irradiating the compounds and by means of their absorption spectra, to obtain thermodynamic parameters that guide us to elucidate how this photodegradative process occurs.
Rhenium compounds have attracted special interest due to the large number of applications that have been discovered the last decades, both in environmental and medicinal applications. A great amount of research related to ReI -diimine complexes has been developed during the last decade, however the photoproduct or reactive species generation, remain mostly unexplored, which could also have potential use in practical applications such as synthesis, remediation or photodynamic therapy (PDT). Rhenium(I) complexes with hybrid P,N-bidentate ligands, like 2-pyridyl diphenylphosphine, have been prepared for synthetic or catalytic purposes. Our group have recently reported the syntheses and photophysical properties of rhenium(I) tricarbonyl complexes with a phosphine-imine ligand: [P,N- {(C6H5)2(C5H4N)P}Re(CO)3Br] (RePNBr), [P,N-{(C6H5)2(C5H4N)P}Re(CO)3(O CF3SO3)] (RePNTfO) and [P,N-{(C6H5)2(C5H4N)NHP}Re(CO)3Br] (RePNNBr) (Scheme 1), but their photochemical behavior were unexplored. Therefore, it is very important to know how its photodegradation mechanism is going on, which opens a way to be able to understand its performance and the subsequent improvement of these applications. In order to understand this mechanism, photochemical tools were used, such as irradiating the compounds and by means of their absorption spectra, to obtain thermodynamic parameters that guide us to elucidate how this photodegradative process occurs.
Notas
Unidad de Investigación (Licenciado en Química)
Financiado por FONDECYT 1200903 FONDECYT 1160749 UNAB DI-1253-16/R
Financiado por FONDECYT 1200903 FONDECYT 1160749 UNAB DI-1253-16/R
Palabras clave
Compuestos de Renio, Fotoquímica