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Estudios espectroscópicos de RMN de estado sólido 67Zn y cálculos orbitales moleculares ab initio en un análogo
Andrew S Lipton1, Catherine Bergquist, Gerard Parkin
1Macromolecular Structure & Dynamics Directorate, WR Wiley Environmental Molecular Sciences Laboratory, Richland, Washington 99352, USA.
Journal of the American Chemical Society
|March 27, 2003
Resumen
La espectroscopia de RMN de estado sólido 67Zn a baja temperatura reveló que la constante de acoplamiento cuádrupolo en los complejos de zinc aumenta con la electronegatividad del sustituyente. Este hallazgo ayuda a comprender los sitios activos del zinc, como en la anhidrase carbónica.
Área de la Ciencia:
- Química Inorgánica La Química Inorgánica es la química inorgánica.
- Espectroscopia de RMN en estado sólido.
- Química organometálica Química orgánica de los metales.
Sus antecedentes:
- Los ligandos Tris ((pyrazolyl) hidroborato son versátiles en la estabilización de los centros metálicos.
- Los complejos de zinc juegan un papel crucial en los sistemas biológicos, especialmente en enzimas como la anhidrase carbónica.
- La espectroscopia de RMN de estado sólido proporciona información detallada sobre el entorno electrónico de los núcleos cuádrupolares.
Objetivo del estudio:
- Para investigar las propiedades electrónicas de los complejos de zinc con diferentes sustituyentes utilizando RMN en estado sólido.
- Para correlacionar los datos espectroscópicos con la electronegatividad del sustituyente.
- Para modelar el sitio activo de la anidrasa carbónica utilizando métodos computacionales.
Principales métodos:
- Se empleó la espectroscopia de RMN 67Zn de estado sólido a baja temperatura.
- Síntesis y caracterización de los complejos de zinc tris (pyrazolyl) hidroborato [Tp (but, Me) ] ZnX (X = Br, Cl, OH).
- Cálculos computacionales de tensores de gradiente de campo eléctrico para complejos de modelos.
Principales resultados:
- La constante de acoplamiento cuádruple (Cq) para el zinc mostró un aumento monotónico con la electronegatividad del sustituyente X (Br < Cl << OH).
- Los datos experimentales de RMN para [Tp(Pero,Me) ]ZnOH fueron consistentes con los resultados computacionales.
- Los cálculos sobre un complejo de hidróxido de zinc de metilimidazol, que modela la anhidrase carbónica, mostraron un buen acuerdo con los valores experimentales y calculados.
Conclusiones:
- El entorno electrónico del centro de zinc es sensible a la naturaleza del sustituto unido.
- La RMN 67Zn de estado sólido es una herramienta valiosa para sondear estructuras electrónicas en complejos organometálicos.
- El estudio proporciona información sobre la química de coordinación del zinc relevante para los sistemas biológicos.
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