Video Experimental Relacionado
Updated: Jun 9, 2026
09:45
A Protocol for Safe Lithiation Reactions Using Organolithium Reagents
Published on: November 12, 2016
Caracterización experimental y estudio computacional de dianiones de litio quelados con C,N únicos
Jocelyn M Gruver1, Scott P West, David B Collum
1Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853-1301, USA.
Journal of the American Chemical Society
|September 9, 2010
Resumen
Los investigadores identificaron la estructura de un nuevo dilitio dianión C,N-quelado. Esta estructura única y ordenada es clave para su función en la formación de enlaces oxidativos carbono-nitrógeno.
Área de la Ciencia:
- Química organometálica Química orgánica de los metales.
- Química supramolecular de las moléculas.
Sus antecedentes:
- Los compuestos quelados C,N son importantes intermediarios en la síntesis orgánica.
- Comprender la estructura de las especies reactivas es crucial para controlar las reacciones químicas.
Objetivo del estudio:
- Para dilucidar la estructura de un único C,N-quelado dilitio dianión.
- Investigar la relación entre la estructura del dianión y su reactividad.
Principales métodos:
- Espectroscopía de Resonancia Magnética Nuclear (RMN) Espectroscopía de Resonancia Magnética Nuclear (RMN) Espectroscopía de Resonancia Magnética Nuclear (RMN) Espectroscopía de Resonancia Magnética Nuclear (RMN) Espectroscopía de Resonancia Magnética Nuclear (RMN) Espectroscopía de Resonancia Magnética Nuclear (RMN) Espectroscopía de Resonancia Magnética Nuclear (RMN) Espectroscopía de Resonancia Magnética Nuclear (RMN) Espectroscopía de Resonancia Magnética Nuclear (RMN).
- Técnicas de química computacional (por ejemplo, cálculos de DFT).
Principales resultados:
- El dilitio dianión quelado con C,N existe como una especie monomérica solvatada.
- Se determinó una estructura altamente ordenada para el dianion.
- Se propone que las características estructurales influyan en su reactividad.
Conclusiones:
- Se ha establecido la estructura precisa del dilitio dianion.
- La estructura ordenada es potencialmente vital para su papel en la formación de enlaces oxidativos C-N.
Videos de Conceptos Relacionados
01:19Complexation Equilibria: The Chelate Effect
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...
02:51Metal-Ligand Bonds
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...
01:22EDTA: Chemistry and Properties
Polydentate ligands are most widely used in complexometric titrations because they form more stable complexes with the metal ions than mono- or bidentate ligands due to the chelate effect. Examples of polydentate ligands are ethylenediaminetetraacetic acid (EDTA), crown ethers, and cryptands. The most important feature of optimal polydentate ligands is the ability to form 1:1 complexes in a single-step process. Amino carboxylic acid derivatives are frequently used as complexing agents. EDTA is...
00:56Extraction: Advanced Methods
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 formed in...
02:58Crystal Field Theory - Octahedral Complexes
Crystal Field Theory
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...
02:42Valence Bond Theory
Coordination compounds and complexes exhibit different colors, geometries, and magnetic behavior, depending on the metal atom/ion and ligands from which they are composed. In an attempt to explain the bonding and structure of coordination complexes, Linus Pauling proposed the valence bond theory, or VBT, using the concepts of hybridization and the overlapping of the atomic orbitals. According to VBT, the central metal atom or ion (Lewis acid) hybridizes to provide empty orbitals of suitable...