Video Experimental Relacionado

Updated: Jun 5, 2026

Accessing Valuable Ligand Supports for Transition Metals: A Modified, Intermediate Scale Preparation of 1,2,3,4,5-Pentamethylcyclopentadiene

Accessing Valuable Ligand Supports for Transition Metals: A Modified, Intermediate Scale Preparation of 1,2,3,4,5-Pentamethylcyclopentadiene

Published on: March 20, 2017

Hidritos catiónicos de alquil aluminio complejo de zirconoceno: identificación espectroscópica por RMN, determinación

Steven M Baldwin¹, John E Bercaw, Lawrence M Henling

¹Arnold and Mabel Beckman Laboratories of Chemical Synthesis, California Institute of Technology, Pasadena, California 91125, United States.

Journal of the American Chemical Society

|January 20, 2011

Resumen

Los complejos de dicloruro de circonoceno reaccionan con los alquilos de aluminio para formar nuevas especies de hidruro catiónico. Estas especies están implicadas en la catálisis de polimerización de olefinas, destacando su importancia en los sistemas catalizadores.

Área de la Ciencia:

Química organometálica Química orgánica de los metales.
La catálisis es la catálisis.
La ciencia de los polímeros es la ciencia de los polímeros.

Sus antecedentes:

Los complejos de circonoceno son cruciales en la polimerización de las olefinas.
Comprender las especies activas en estos sistemas catalíticos es esencial para la optimización.

Objetivo del estudio:

Para sintetizar y caracterizar los nuevos complejos de hidruro de circonoceno catiónico.
Para investigar la reactividad de estos complejos con los alquilos de aluminio.
Para aclarar el papel de estas especies en la polimerización activada por metilalumoxano.

Principales métodos:

Reacción del dicloruro de ansa-zirconoceno con el hidruro de diisobutilaluminio y el tetraquiso de tritilo ((perfluorofenil) borato.
Espectroscopia de RMN para elucidación estructural.
Cristalografía de rayos X para la determinación estructural.
Investigando las reacciones con varios alquilos de aluminio (por ejemplo, ClAl{i}Bu{2}, AlMe{3}).

Principales resultados:

Síntesis del complejo de hidruro catiónico [(SBI) Zr ((μ-H) ((3) ((Al ((i) Bu ((2)) ((2))) ((+)).
Caracterización del catión hidruro mediante RMN y cristalografía de rayos X. Caracterización del catión hidruro mediante RMN y cristalografía de rayos X.
Observación de reacciones reversibles con ClAl (i) Bu (ii) formando cationes con dicloro puente.
Formación de especies mezcladas de alquilo y metilo puentes tras la reacción con AlMe (((3).
Demostración de que el catión hidruro predomina en equilibrio con el AlMe(3).

Conclusiones:

Se pueden sintetizar y caracterizar nuevos complejos de hidruro de circonoceno catiónico.
Estos cationes hidruro son intermediarios clave en las reacciones con los alquilos de aluminio.
Los hallazgos implican el catión hidruro como una especie crucial en la catálisis de polimerización de olefinas.

Más Videos Relacionados

The Synthesis, Characterization and Reactivity of a Series of Ruthenium N-triphosPh Complexes

The Synthesis, Characterization and Reactivity of a Series of Ruthenium N-triphos^Ph Complexes

Published on: April 10, 2015

Co-localizing Kelvin Probe Force Microscopy with Other Microscopies and Spectroscopies: Selected Applications in Corrosion Characterization of Alloys

Co-localizing Kelvin Probe Force Microscopy with Other Microscopies and Spectroscopies: Selected Applications in Corrosion Characterization of Alloys

Published on: June 27, 2022

Videos de Conceptos Relacionados

Electrophilic Addition to Alkynes: Halogenation

Electrophilic Addition to Alkynes: Halogenation

Introduction
Halogenation is another class of electrophilic addition reactions where a halogen molecule gets added across a π bond. In alkynes, the presence of two π bonds allows for the addition of two equivalents of halogens (bromine or chlorine). The addition of the first halogen molecule forms a trans-dihaloalkene as the major product and the cis isomer as the minor product. Subsequent addition of the second equivalent yields the tetrahalide.

Structural Isomerism

Structural Isomerism

Isomerism in Complexes
Isomers are different chemical species that have the same chemical formula. Structural isomerism of coordination compounds can be divided into two subcategories, the linkage isomers and coordination-sphere isomers.
Linkage isomers occur when the coordination compound contains a ligand that can bind to the transition metal center through two different atoms. For example, the CN− ligand can bind through the carbon atom or through the nitrogen atom. Similarly, SCN− can be...

Regioselectivity and Stereochemistry of Acid-Catalyzed Hydration

Regioselectivity and Stereochemistry of Acid-Catalyzed Hydration

The rate of acid-catalyzed hydration of alkenes depends on the alkene's structure, as the presence of alkyl substituents at the double bond can significantly influence the rate.

Ionic Crystal Structures

Ionic Crystal Structures

Ionic crystals consist of two or more different kinds of ions that usually have different sizes. The packing of these ions into a crystal structure is more complex than the packing of metal atoms that are the same size.
Most monatomic ions behave as charged spheres, and their attraction for ions of opposite charge is the same in every direction. Consequently, stable structures for ionic compounds result (1) when ions of one charge are surrounded by as many ions as possible of the opposite...

Alkenes via Reductive Coupling of Aldehydes or Ketones: McMurry Reaction

Alkenes via Reductive Coupling of Aldehydes or Ketones: McMurry Reaction

The radical dimerization of ketones or aldehydes gives vicinal diols through a pinacol coupling reaction. However, the behavior of titanium metals used for the reaction as a source of electrons is unusual. When the reaction is carried out in the presence of titanium, diols can be isolated at low temperatures. Else titanium further reacts with diols, forming alkenes through the McMurry reaction.

Aldehydes and Ketones with HCN: Cyanohydrin Formation Mechanism

Aldehydes and Ketones with HCN: Cyanohydrin Formation Mechanism

Cyanohydrins are formed when cyanide nucleophiles and carbonyl compounds like aldehydes and ketones react. A strong base, the cyanide ion, catalyzes cyanohydrin formation. The ions are generated from HCN under aqueous conditions. Once the cyanide ions are generated, the first step involves the nucleophilic attack of the cyanide ions on the electrophilic carbonyl carbon. This attack shifts the π electrons from the C=O to the oxygen atom forming the alkoxide ion intermediate. The alkoxide anion...