Video Experimental Relacionado
Updated: Jan 19, 2026
10:09
Synthesis and Characterization of Amphiphilic Gold Nanoparticles
Published on: July 2, 2019
18.1K
Influencia trans de los ligandos en la oxidación de los complejos de oro
Yangyang Yang1, Lukas Eberle1, Florian F Mulks1
1Organisch-Chemisches Institut , Heidelberg University , Im Neuenheimer Feld 270 , 69120 Heidelberg , Germany.
Journal of the American Chemical Society
|September 27, 2019
Resumen
Los complejos de oro (I) se someten a adición oxidativa a través de un intermediario de tri o tetra coordenadas. Los ligandos de fosfina que donan débilmente mejoran la accesibilidad del oro, aumentando las tasas de adición oxidativa y confirmando el papel crítico de la influencia trans.
Área de la Ciencia:
- Química organometálica
- Catálisis
- Química computacional
Sus antecedentes:
- Los complejos de oro (I) son clave en las reacciones de adición oxidativa.
- El mecanismo difiere de otros metales de transición tardía, que carecen de una comprensión clara.
- La reactividad está influenciada por el número de coordinación y las propiedades del ligando.
Objetivo del estudio:
- Investigar el papel del oro en la accesibilidad al centro en la adición oxidativa.
- Para correlacionar las propiedades del ligando, específicamente la influencia trans, con la reactividad.
- Para aclarar el mecanismo de adición oxidativa a los complejos de oro.
Principales métodos:
- Estudio computacional de la geometría compleja de (Phen) R3PAu (I) NTf2.
- Análisis cinético de la adición oxidativa mediante el uso de reactivos de yodo hipervalentes alquiniles.
- Correlación de las velocidades de reacción con el parámetro de sustitución de Hammett (ρ).
Principales resultados:
- La accesibilidad de los ligandos a la coordinación tri o tetra es crítica para la adición oxidativa.
- Los ligandos de fosfina que donan σ débilmente promueven la tricoordinación y aumentan las tasas de adición oxidativa.
- Un parámetro de Hammett positivo (ρ = 3,75) indica una alta sensibilidad a la influencia trans.
Conclusiones:
- La influencia trans de los ligandos de la fosfina dicta la accesibilidad del centro de oro.
- Los ligandos con una pequeña influencia trans aceleran la adición oxidativa a los complejos de oro.
- Comprender este mecanismo es crucial para diseñar reacciones eficientes catalizadas por oro.
Más Videos Relacionados
Videos de Conceptos Relacionados
02:51Metal-Ligand Bonds
24.0K
The hemoglobin in the blood, the chlorophyll in green plants, vitamin B-12, and the catalyst used in the manufacture of polyethylene all contain coordination compounds. Ions of the metals, especially the transition metals, are likely to form complexes.
In these complexes, transition metals form coordinate covalent bonds, a kind of Lewis acid-base interaction in which both of the electrons in the bond are contributed by a donor (Lewis base) to an electron acceptor (Lewis acid). The Lewis acid in...
In these complexes, transition metals form coordinate covalent bonds, a kind of Lewis acid-base interaction in which both of the electrons in the bond are contributed by a donor (Lewis base) to an electron acceptor (Lewis acid). The Lewis acid in...
24.0K
01:09Complexation Equilibria: Factors Influencing Stability of Complexes
804
In complexation reactions, metal cations are the electron pair acceptors, and the ligands are the electron pair donors. The stability of the metal complexes depends primarily on the complexing ability of the central metal ion and the nature of the ligands. Generally, the complexing ability of the metal ion depends on the size and charge of the ion. As the metal ion size increases, the stability of the metal complexes decreases, provided that the valency of the metal ion and the ligands remain...
804
02:57Coordination Number and Geometry
18.9K
For transition metal complexes, the coordination number determines the geometry around the central metal ion. Table 1 compares coordination numbers to molecular geometry. The most common structures of the complexes in coordination compounds are octahedral, tetrahedral, and square planar.
18.9K
01:19Complexation Equilibria: The Chelate Effect
1.2K
In complexation reactions, metal atoms or cations interact with ligands to form donor-acceptor adducts called metal complexes. Ligands that bind through one donor site are monodentate, ligands with two donor sites are bidentate, and those with more than two donor sites are polydentate ligands. For example, ethylene diamine is a bidentate ligand that binds through two nitrogen donor atoms, forming a five-membered ring. EDTA is a polydentate ligand that binds through four oxygen and two nitrogen...
1.2K
00:43Complexometric Titration: Ligands
2.2K
Different monodentate and polydentate ligands are used as complexing agents in complexometric titration reactions. The formation of complexes by mono- and bidentate ligands involves two or more intermediate steps, limiting their use as complexing agents. In comparison, polydentate ligands can form complexes with metal ions in a single-step process, facilitating sharper end points. This means polydentate ligands, such as amino carboxylic acid derivatives, are most commonly employed in...
2.2K
00:56Extraction: Advanced Methods
1.1K
Metal ions can be separated from one another by complexation with organic ligands–the chelating agent– to form uncharged chelates. Here, the chelating agent must contain hydrophobic groups and behave as a weak acid, losing a proton to bind with the metal. Since most organic ligands used in this process are insoluble or undergo oxidation in the aqueous phase, the chelating agent is initially added to the organic phase and extracted into the aqueous phase. The metal-ligand complex is...
1.1K