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Efectos de sustitución en las interacciones de enlaces de hidrógeno CH: Relaciones de energía libre lineales e
Blakely W Tresca1, Ryan J Hansen1, Calvin V Chau1
1Department of Chemistry & Biochemistry and the Materials Science Institute, University of Oregon , Eugene, Oregon 97403-1253, United States.
Journal of the American Chemical Society
|November 6, 2015
Resumen
Este estudio investiga experimentalmente los enlaces de hidrógeno arilo-CH (HBs) y los efectos de los sustituyentes. Los resultados revelan que los parámetros electrostáticos dominan, pero el tipo de anión influye únicamente en la fuerza de HB en la solución.
Área de la Ciencia:
- Química supramolecular
- Química orgánica
- Química computacional
Sus antecedentes:
- Los enlaces de hidrógeno arilo CH (HB) son cruciales en biología molecular, catálisis y química supramolecular.
- La comprensión de los efectos de los sustituyentes sobre la fuerza y la selectividad de CH HB es vital para las aplicaciones.
- Los estudios anteriores se centraron en el análisis computacional, careciendo de validación experimental de los efectos de los sustituyentes.
Objetivo del estudio:
- Investigar sistemáticamente los efectos de los sustituyentes en un enlace de hidrógeno arilo-CH único de forma experimental.
- Para correlacionar los datos de unión experimentales con parámetros de sustitución computacionales y empíricos.
- Explorar la influencia de los aniones en la relación estructura-actividad de los CH HBs en solución.
Principales métodos:
- Utilizó donantes de urea dentro de una cavidad de unión supramolecular para dirigir un CH HB específico.
- Constantes de asociación determinadas experimentalmente para varios donantes de urea sustituidos.
- Efectos de sustitución analizados utilizando cálculos de potencial electrostático computacional (ESP) y parámetros empíricos (σm, σp).
Principales resultados:
- Las constantes de asociación experimentales demostraron una clara relación con las modificaciones de los sustituyentes.
- Los estudios DFT computacionales confirmaron el predominio de las interacciones electrostáticas en la fuerza de CH HB.
- Se observó una nueva dependencia de los efectos sustitutivos en la naturaleza del contraanión en solución.
Conclusiones:
- Este trabajo proporciona la primera validación experimental de los efectos de los sustituyentes sobre el arilo CH HBs.
- Las contribuciones electrostáticas son clave, alineándose con las predicciones teóricas.
- La dependencia aniónica descubierta ofrece nuevas ideas para el diseño de sistemas basados en CH HB.
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