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Efectos de las interacciones intermoleculares débiles en el isomerismo molecular de las cadenas metálicas de
Rasmus D Poulsen1, Jacob Overgaard, Alexander Schulman
1Department of Chemistry, University of Aarhus, DK-8000 Aarhus, Denmark.
Journal of the American Chemical Society
|May 15, 2009
Resumen
El isomerismo de la estructura cristalina en los complejos de cobalto está influenciado por las moléculas de disolventes y el empaque de cristales. El análisis de Hirshfeld revela diferencias en las interacciones intermoleculares que afectan las disposiciones moleculares y la unión metal-metal.
Área de la Ciencia:
- Química Inorgánica La química inorgánica es la química inorgánica.
- Química del estado sólido.
- La cristalografía es una técnica de cristalografía.
Sus antecedentes:
- Los complejos de cobalto de cadena lineal, Co ((3) ((dipiridilamida)) ((4) Cl ((2) x nCH ((2) Cl ((2), exhiben estructuras simétricas o no simétricas basadas en el contenido de disolvente intersticial.
- Comprender los factores que rigen estas variaciones estructurales es crucial para predecir y controlar las propiedades de los materiales.
Objetivo del estudio:
- Investigar las razones detrás de la formación de estructuras de cadenas metálicas simétricas versus no simétricas en complejos de cobalto.
- Analizar el papel de las interacciones intermoleculares y el empaque de cristales en la influencia del isomerismo molecular.
Principales métodos:
- Análisis de superficie de Hirshfeld de las interacciones intermoleculares.
- Determinación de la densidad de carga utilizando 100(1) K datos de difracción de rayos X.
- Difracción de rayos X de sincrotrón de cristal único a temperaturas variables (20, 150, 300 K).
Principales resultados:
- Se observaron diferencias significativas en las interacciones intermoleculares entre solvados simétricos y no simétricos a través del análisis de Hirshfeld, lo que indica la influencia del empaque de cristales.
- El análisis topológico reveló un enlace directo metal-metal entre los átomos de cobalto (Co(1) -Co(2) y Co(2) -Co(3)).
- Los átomos de cobalto exhiben distintos entornos electrónicos y cargas topológicas, con Co(3) mostrando más interacciones iónicas y participación en el cruce de espín.
Conclusiones:
- Los efectos de envasado de cristales, influenciados por el contenido de disolventes, juegan un papel importante en la determinación del isomerismo molecular de estos complejos de cobalto.
- El enlace directo metal-metal existe dentro de las cadenas de cobalto, con diversos grados de covalencia y carácter iónico.
- La transición de cruce de espín en Co(3) está vinculada a ocupaciones específicas del orbital d e influye en las longitudes de enlace con la temperatura.
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