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Espectroscopía de RMN de polarización nuclear dinámica de sólidos microcristalinos
Aaron J Rossini1, Alexandre Zagdoun, Franziska Hegner
1Centre de RMN a Tres Hauts Champs, Université de Lyon (CNRS/ENS Lyon/UCB Lyon 1), 69100 Villeurbanne, France.
Journal of the American Chemical Society
|September 13, 2012
Resumen
La RMN de estado sólido de polarización nuclear dinámica (DNP) mejora la sensibilidad a los sólidos orgánicos microcristalinos en más de 60 veces. Este avance permite la adquisición rápida de espectros de RMN de estado sólido detallados para muestras inalteradas.
Área de la Ciencia:
- Espectroscopia de resonancia magnética nuclear de estado sólido (RMN) Espectroscopia de resonancia magnética nuclear de estado sólido (RMN) Espectroscopia de resonancia magnética nuclear de estado sólido (RMN) Espectroscopia de resonancia magnética nuclear de estado sólido
- La polarización nuclear dinámica (DNP, por sus siglas en inglés)
- Ciencia de los materiales Ciencia de los materiales.
Sus antecedentes:
- La espectroscopia de RMN en estado sólido es crucial para caracterizar los sólidos orgánicos microcristalinos.
- Lograr una alta sensibilidad en RMN de estado sólido es a menudo un desafío, lo que limita el análisis rápido.
- La polarización nuclear dinámica (DNP) es una técnica conocida para mejorar la sensibilidad de la señal de RMN.
Objetivo del estudio:
- Aplicar la polarización nuclear dinámica (DNP) a sólidos orgánicos microcristalinos en polvo para mejorar la sensibilidad.
- Investigar el mecanismo de transferencia de polarización en RMN de estado sólido mejorada con DNP.
- Demostrar la capacidad para la adquisición rápida de espectros de RMN en estado sólido de sólidos orgánicos inalterados.
Principales métodos:
- La glucosa microcristalina, el sulfatiazol y el paracetamol fueron impregnados con una solución de bis-nitróxido biradical (bCTbK).
- Los disolventes orgánicos fueron elegidos como no disolventes para preservar el estado sólido de las muestras.
- Los experimentos de RMN de estado sólido mejorados con DNP se llevaron a cabo a 9,4 T y ~ 105 K.
Principales resultados:
- Las mejoras de sensibilidad del orden de 100 se lograron utilizando DNP.
- Se obtuvieron mejoras sustanciales de la DNP (ε ≈ 60) para la glucosa y el sulfatiazol.
- El estudio demostró la capacidad de adquirir espectros de correlación (13)C-(13)C rápidamente en abundancia isotópica natural.
Conclusiones:
- DNP es una técnica poderosa para mejorar significativamente la sensibilidad de la RMN en estado sólido para sólidos orgánicos microcristalinos.
- La difusión de espín protón-protón transmite efectivamente una polarización mejorada a distancias de micrómetros en sólidos dopados.
- Este método ofrece un enfoque general para mejorar la eficiencia de los experimentos de RMN en estado sólido en materiales orgánicos.
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