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Radicales de línea estrecha solubles en agua para la polarización nuclear dinámica
Olesya Haze1, Björn Corzilius, Albert A Smith
1Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA.
Journal of the American Chemical Society
|August 25, 2012
Resumen
Los investigadores desarrollaron nuevos radicales orgánicos solubles en agua para la polarización nuclear dinámica (DNP). Estos agentes basados en BDPA ofrecen mejoras significativas de sensibilidad en RMN, avanzando la tecnología de agentes de polarización.
Área de la Ciencia:
- Química orgánica es la química orgánica.
- Espectroscopia de resonancia magnética Espectroscopia de resonancia magnética
- Ciencia de los materiales Ciencia de los materiales.
Sus antecedentes:
- La polarización nuclear dinámica (DNP, por sus siglas en inglés) mejora la sensibilidad de la RMN utilizando agentes polarizantes.
- Los agentes de polarización de línea estrecha existentes, como los radicales de tritilo, tienen limitaciones.
- El desarrollo de radicales orgánicos estables y solubles en agua es crucial para aplicaciones más amplias de DNP.
Objetivo del estudio:
- Para sintetizar y caracterizar radicales orgánicos estables en el aire y solubles en agua basados en el núcleo 1,3-bis (difenileno) -2-fenilallil (BDPA).
- Para evaluar el rendimiento de un derivado sulfonado (SA-BDPA) como agente polarizador para el DNP de efecto sólido (SE DNP).
- Para comparar la eficacia de los radicales basados en BDPA con los agentes de tipo tritilo existentes.
Principales métodos:
- Síntesis del núcleo de BDPA y su derivado sulfonado (SA-BDPA).
- Espectroscopia de resonancia paramagnética de electrones (EPR) para determinar el ancho de línea.
- Experimentos de polarización nuclear dinámica de efecto sólido (SE DNP, por sus siglas en inglés).
- Espectroscopia de Resonancia Magnética Nuclear (RMN) de ángulo giratorio mágico de alto campo (MAS) para mediciones de mejora de sensibilidad.
Principales resultados:
- Sintetizó con éxito radicales orgánicos basados en BDPA, estables en el aire y altamente solubles en agua.
- SA-BDPA demostró un ancho de línea EPR estrecho (<30 MHz a 5 T) en soluciones concentradas.
- Logró una mejora de sensibilidad de 110 en experimentos de RMN MAS de campo alto utilizando SA-BDPA.
- Los radicales basados en BDPA mostraron facilidad de síntesis y altas mejoras máximas.
Conclusiones:
- Los radicales orgánicos basados en BDPA, particularmente SA-BDPA, son agentes polarizadores efectivos para el SE DNP.
- Estos nuevos radicales ofrecen ventajas significativas sobre los agentes de tipo tritilo en términos de síntesis y rendimiento.
- Los radicales desarrollados representan un gran avance en los materiales para la espectroscopia de RMN de alto campo.
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