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Estudio de temperatura variable de la simetría de los enlaces de hidrógeno en el monoanión
Charles L Perrin1, Kathryn D Burke
1Department of Chemistry, University of California-San Diego , La Jolla, California 92093-0358, United States.
Journal of the American Chemical Society
|February 18, 2014
Resumen
Se estudió la simetría del enlace de hidrógeno en el monoanión ciclohexeno-1,2-dicarboxilato. Los resultados indican que existe como una mezcla de tautómeros que se interconvierten rápidamente, no una sola estructura simétrica.
Área de la Ciencia:
- Química orgánica es la química orgánica.
- Química Física es la química física.
- La espectroscopia es una técnica de espectroscopia.
Sus antecedentes:
- Comprender la simetría del enlace de hidrógeno es crucial en el enlace químico.
- El monoanión ciclohexeno-1,2-dicarboxilato presenta un sistema modelo para el estudio del tautomerismo.
Objetivo del estudio:
- Para determinar la simetría del enlace de hidrógeno en el hidrógeno ciclohexeno-1,2-dicarboxilato monoanión.
- Para investigar el comportamiento dependiente de la temperatura de los efectos de perturbación isotópica.
Principales métodos:
- Se empleó la espectroscopia de resonancia magnética nuclear (RMN).
- Se utilizó la perturbación isotópica utilizando oxígeno-18 ((18) O) para sondear los cambios químicos.
- Los experimentos se llevaron a cabo en cloroformo.
Principales resultados:
- La disminución de la temperatura condujo a un aumento de las separaciones de desplazamiento químico (18) inducidas por O (13) C tanto en los carbonos carboxilo como ipso.
- El aumento observado en los carbonos ipso se alinea con un efecto del isótopo (18) O en la acidez del ácido carboxílico.
Conclusiones:
- El monoanión ciclohexeno-1,2-dicarboxilato existe como una mezcla de tautómeros en equilibrio rápido.
- La dependencia de temperatura observada contradice una sola estructura simétrica con mecanismos de acoplamiento vibratorio específicos.
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