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Desde un complejo paramagnético, mononuclear supersulfidonickel (II) hasta un dímer diamagnético con un enlace de dos
Shenglai Yao1, Carsten Milsmann, Eckhard Bill
1Metalorganics and Inorganic Materials, Institute of Chemistry, Technische Universität Berlin, Strasse des 17, Juni 135, Sekr. C2, D-10623 Berlin, Germany.
Journal of the American Chemical Society
|September 23, 2008
Resumen
Los investigadores sintetizaron el primer complejo de supersulfuro de níquel (II) aislable, que incluye el elusivo S2-. ligando. el ligando. el ligando. Este complejo paramagnético se dimeriza para formar una especie diamagnética con un enlace único de cuatro enlaces de azufre.
Área de la Ciencia:
- Química Inorgánica La Química Inorgánica es la química inorgánica.
- Química organometálica Química orgánica de los metales.
- Química del azufre Química del azufre
Sus antecedentes:
- El ligando supersulfuro (S2^2-) es altamente reactivo y difícil de aislar en complejos de coordinación estables.
- Estudios anteriores se han centrado en formas transitorias o menos caracterizadas de complejos de supersulfuro.
- Comprender la química de coordinación de los ligandos de azufre es crucial para la catálisis y la ciencia de los materiales.
Objetivo del estudio:
- Para sintetizar y caracterizar el primer níquel aislable "de lado" (II) complejo de supersulfuro.
- Investigar las propiedades estructurales y electrónicas del complejo de supersulfuro sintetizado y su dimero.
- Para explorar la reactividad del complejo de supersulfuro en las reacciones de transferencia de azufre.
Principales métodos:
- Síntesis por oxidación fácil de un precursor del níquel con azufre elemental.
- Caracterización estructural utilizando análisis de difracción de rayos X.
- Análisis espectroscópico que incluye 1H RMN, EPR y magnetometría SQUID.
- Estudios computacionales utilizando cálculos de la Teoría Funcional de la Densidad (DFT).
Principales resultados:
- Síntesis exitosa del primer níquel aislable "de lado" (II) complejo de supersulfuro (1).
- Demostración de la dimerización voluntaria del complejo paramagnético supersulfuro (1) a un dímer diamagnético (1(2) con un enlace de cuatro azufre y dos electrones.
- Evidencia de las capacidades de transferencia de azufre del complejo supersulfuro a los ligandos de fosfina y precursores de níquel, formando complejos disulfuro (3).
Conclusiones:
- El estudio informa de la estabilización y aislamiento del esquivo ligando S2^2- en un complejo de níquel (II).
- El comportamiento de la dimerización destaca nuevos modos de unión para los ligandos de polisulfuro.
- El complejo de supersulfuro sintetizado sirve como un valioso precursor para los complejos de disulfuro y las reacciones de transferencia de azufre.
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