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Un catión de estanilio tricoordinado libre y libre.
Joseph B Lambert1, Lijun Lin, Shahar Keinan
1Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, USA.
Journal of the American Chemical Society
|June 6, 2003
Resumen
Este estudio revela un catión de estabilidad de estaño tricoordinado libre, Tris ((2,4,6-triisopropilfenil) stannylium, confirmado por métodos de rayos X y DFT. La investigación aclara su estructura y enlace únicos, avanzando en la química de la organotina.
Área de la Ciencia:
- Química organometálica Química orgánica de los metales.
- Química Inorgánica La Química Inorgánica es la química inorgánica.
- Química del estado sólido.
Sus antecedentes:
- Los cationes de estaño tricoordinados son especies raras y altamente reactivas.
- Comprender su estructura y unión es crucial para desarrollar nuevas metodologías sintéticas.
- Estudios anteriores a menudo han involucrado cationes de estaño transitorios o solvados.
Objetivo del estudio:
- Para sintetizar y caracterizar una estabilidad, cation libre tricoordinado de estaño.
- Para dilucidar las propiedades estructurales y electrónicas de la Tris (2,4,6-triisopropilfenil) catión de estanilo.
- Para investigar las posibles interacciones agósticas y confirmar la estructura electrónica del catión.
Principales métodos:
- Difracción de rayos X monocristalino para determinar el arreglo atómico preciso.
- Cálculos de la Teoría Funcional de Densidad (DFT) para el análisis estructural y electrónico.
- Espectroscopia de Resonancia Magnética Nuclear (RMN), específicamente RMN 119Sn, para sondear el entorno del estaño.
Principales resultados:
- La estructura de rayos X confirmó un catión de estaño libre y tricoordinado sin coordinación de disolvente o contraanión.
- Los cálculos de DFT apoyaron la estructura observada y descartaron la unión agóstica entre los grupos isopropílicos y el átomo de estaño.
- El desplazamiento químico calculado de 119Sn mostró una excelente concordancia con el valor experimental, validando la estructura electrónica.
Conclusiones:
- El borato de tris ((2,4,6-triisopropilfenilo) estanilio tetráquico ((pentafluorofenilo) representa un raro ejemplo de un catión de estabilidad de estaño tricoordinado aislable.
- Los voluminosos grupos triisopropilfenilo protegen eficazmente el centro de estaño, evitando la coordinación no deseada.
- Este trabajo proporciona información valiosa sobre la química fundamental de los compuestos organotínicos hipervalentes.
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