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Cambio conformacional fotoinducido de azobenzenos enantiopuros controlados por un sulfóxido
M Carmen Carreño1, Isabel García, Irene Núñez
1Departamento de Química Orgánica (C-I), Universidad Autónoma de Madrid, Cantoblanco, 28049-Madrid, Spain. carmen.carrenno@uam.es
Journal of the American Chemical Society
|May 15, 2007
Resumen
Los azobenzenos sulfóxido quiral actúan como interruptores moleculares, demostrando la transferencia de quiralidad y cambios conformacionales distintos tras la fotoisomerización. Estas propiedades permiten aplicaciones de conmutación molecular fotocontroladas.
Área de la Ciencia:
- Química orgánica es la química orgánica.
- Química supramolecular de las moléculas.
- La fotoquímica es la fotoquímica.
Sus antecedentes:
- Los azobenzenos son ampliamente utilizados como interruptores moleculares fotorresponsivos.
- La quiralidad en los interruptores moleculares puede introducir funcionalidades avanzadas.
- Los grupos sulfóxidos ofrecen centros estereogénicos y propiedades electrónicas únicas.
Objetivo del estudio:
- Para sintetizar azobenzenos enantiopuros con sustituyentes de orto/meta p-tolylsulfoxide. para la síntesis de azobenzenos enantiopuros con sustituyentes de orto/meta p-tolylsulfoxide. para la síntesis de azobenzenos enantiopuros con sustituyentes de orto/meta p-tolylsulfoxide.
- Para investigar su comportamiento de fotoisomerización y sus propiedades quirales.
- Para explorar su potencial como interruptores moleculares fotocontrolados.
Principales métodos:
- Síntesis regioselectiva de los derivados del azobenzeno.
- Estudios de fotoisomerización utilizando UV-vis y dicroísmo circular (CD).
- Análisis estructural mediante RMN y cromatografía líquida quiral de alto rendimiento (HPLC).
Principales resultados:
- Síntesis exitosa de dos series de azobenzenos enantiopuros con grupos sulfóxidos.
- Observación de la transferencia de quiralidad del sulfóxido al sistema azo, dependiente de los isómeros.
- La RMN reveló distintas conformaciones en forma de U (cis-3) y en forma de S (cis-7).
- Diferencias significativas en las rotaciones ópticas específicas para los isómeros trans y cis.
Conclusiones:
- El grupo sulfóxido juega un doble papel en la fotoisomerización y el control de la conformación.
- Se forman distintas entidades quirales en estados fotostacionarios.
- Estos azobenzenos son prometedores para aplicaciones de conmutación molecular fotocontrolada.
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