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Polarización nuclear dinámica en estado sólido a 9,4 y 18,8 T desde 100 K hasta la temperatura ambiente

Moreno Lelli¹, Sachin R Chaudhari¹, David Gajan¹

¹Institut de Sciences Analytiques, Centre de RMN à Très Hauts Champs, Université de Lyon (CNRS/ENS Lyon/UCB Lyon 1) , 69100 Villeurbanne, France.

Journal of the American Chemical Society

|November 12, 2015

Resumen

Los experimentos de resonancia magnética nuclear (RMN) de alta sensibilidad que utilizan la polarización nuclear dinámica (DNP) ahora son posibles a temperaturas más altas. Los investigadores lograron mejoras significativas de (1) H DNP a 240 K utilizando un disolvente específico, lo que permitió nuevas aplicaciones.

Área de la Ciencia:

Espectroscopia de resonancia magnética nuclear (RMN) en estado sólido
Técnicas de polarización nuclear dinámica (DNP)
Ciencias de los materiales y química física

Sus antecedentes:

La polarización nuclear dinámica (DNP) mejora significativamente la sensibilidad de la señal de RMN.
Los métodos actuales de DNP suelen estar restringidos a bajas temperaturas (≤ 100 K).
El DNP a temperatura más alta es crucial para aplicaciones más amplias, especialmente en la ciencia biológica y de los materiales.

Objetivo del estudio:

Investigar la viabilidad de lograr una polarización nuclear dinámica eficiente (DNP) a temperaturas elevadas.
Explorar el uso de disolventes y biradicales específicos para el DNP a alta temperatura.
Aplicar DNP a alta temperatura para el seguimiento de la dinámica molecular en compuestos farmacéuticos sólidos.

Principales métodos:

Utilizó el TEKPol biradical disuelto en orto-terfenilo (OTP) como un sistema de disolvente.
Se han realizado experimentos de DNP con efecto cruzado (1) H en un rango de temperatura de 100-300 K.
Realizó experimentos con fuerzas de campo magnético de 9.4 y 18.8 Tesla.
Aplicó DNP para estudiar las transiciones dinámicas moleculares en sólidos de Ambroxol e Ibuprofeno.

Principales resultados:

Se obtienen mejoras de DNP de efecto cruzado (1) H superiores a 80 a 240 K.
Se observó una disminución relativamente lenta de la potenciación de DNP por encima de la temperatura de transición de vidrio (Tg = 243 K) de OTP.
(1) Se obtuvieron mejoras de H DNP de 1520 a temperatura ambiente.
Se han monitorizado con éxito las transiciones dinámicas moleculares en Ambroxol e Ibuprofeno utilizando el método DNP desarrollado.

Conclusiones:

Se puede lograr un DNP eficiente a alta temperatura seleccionando sistemas de disolventes adecuados, como el orto-terfenilo (OTP).
El método desarrollado permite realizar estudios de RMN mejorados con DNP a temperaturas significativamente superiores a los límites convencionales.
Esta técnica proporciona una herramienta valiosa para investigar la dinámica molecular en materiales en estado sólido farmacéuticamente relevantes en condiciones cercanas al ambiente.

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