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Espectroscopia de fotoelectrones UV de los indoles BN: análisis de la estructura electrónica experimental y

Anna Chrostowska¹, Senmiao Xu, Audrey Mazière

¹Department of Chemistry, Boston College , Chestnut Hill, Massachusetts 02467, United States.

Journal of the American Chemical Society

|August 5, 2014

Resumen

Este estudio analiza los análogos indólicos de boro-nitrógeno (BN) utilizando espectroscopia UV-fotoelectrónica y química computacional. El isosterismo BN impacta la estructura electrónica y la reactividad de manera diferente en los sistemas bicíclicos en comparación con los monocíclicos.

Área de la Ciencia:

Química Física es la química física.
Química computacional es la química computacional.
La espectroscopia es una técnica de espectroscopia.

Sus antecedentes:

Los derivados del indole son cruciales en la química medicinal y la ciencia de los materiales.
Comprender la estructura electrónica del indol es esencial para predecir sus propiedades.
El isosterismo de boro-nitrógeno (BN) ofrece una ruta para modificar los sistemas aromáticos.

Objetivo del estudio:

Para investigar la estructura electrónica de dos isósteros BN del indole.
Para comparar sus propiedades con el indole natural utilizando métodos experimentales y computacionales.
Para evaluar el impacto del isosterismo BN/CC en el núcleo indólico.

Principales métodos:

Espectroscopia de fotoelectrones UV (UV-PES) en fase gaseosa con radiación He I.
Cálculos de la Teoría Funcional de Densidad (DFT) para la estructura electrónica.
Análisis de las energías de ionización, los momentos dipolo, la absorción UV-vis, y la sustitución aromática electrofílica.

Principales resultados:

Las primeras energías de ionización: indol (7,9 eV), indol BN externo I (7,9 eV), el indol BN fundido II (8,05 eV).
Momentos dipolo: indole (2.177 D) > indole BN fundido II (1.512 D) > indole BN externo I (0.543 D). • El momento dipolo es el mismo que el momento dipolo. • El momento dipolo es el mismo que el momento dipolo.
Absorción frente a los rayos UV (λmax): el indole II de BN fundido (292 nm) > el indole I de BN externo (282 nm) > el indole (270 nm).
Tendencia de reactividad: BN fundido indole II > indole > BN externo indole I.
La introducción de BN reduce la aromaticidad en el sistema de electrones 6π.

Conclusiones:

El isosterismo BN altera significativamente la estructura electrónica y la reactividad del núcleo de indol.
Las tendencias observadas difieren de las de los sistemas monocíclicos, lo que requiere una evaluación específica del sistema.
Los efectos de isosterismo BN/CC no son universalmente transferibles y requieren una evaluación individual.

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