Video Experimental Relacionado
Updated: Jun 21, 2026
09:22
Self-assembling Morphologies Obtained from Helical Polycarbodiimide Copolymers and Their Triazole Derivatives
Published on: February 7, 2017
Activación de enlaces, adición de sustrato y catálisis por un monómero bis-isocianuro aislable de dos coordenadas
Liezel A Labios1, Matthew D Millard, Arnold L Rheingold
1Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, Mail Code 0358, La Jolla, California 92093-0358, USA.
Journal of the American Chemical Society
|July 28, 2009
Resumen
Se sintetizó un nuevo complejo de isocyanuro de bis-paladio de dos coordenadas estables, Pd, CNAr, Dipp2)), fue sintetizado. Este complejo es activo en la adición oxidativa y las reacciones de acoplamiento cruzado, mostrando una reactividad única con varios sustratos.
Área de la Ciencia:
- Química organometálica Química orgánica de los metales.
- Catalización con el paladio.
- Los complejos de isocianuros.
Sus antecedentes:
- Los complejos de paladio zerovalente son cruciales en la catálisis.
- Los complejos estables de paladio de baja coordinación son sintéticamente difíciles.
- Los isocyanuros son ligandos versátiles en la química de la coordinación.
Objetivo del estudio:
- Para sintetizar y caracterizar un nuevo complejo de dos coordenadas de paladio ((0) bis-isocianuro.
- Para investigar la reactividad y las aplicaciones catalíticas de este nuevo complejo.
- Explorar las propiedades electrónicas y estructurales del sistema de isocyanuro de paladio.
Principales métodos:
- Síntesis a través de la reducción de metal de magnesio de un precursor divalente de paladio.
- Caracterización utilizando una temperatura variable (1)H RMN y espectroscopia FTIR.
- Estudios de reactividad que incluyen adición oxidativa, acoplamiento Suzuki-Miyaura y reacciones con sustratos insaturados.
- Análisis computacional utilizando la teoría funcional de la densidad (DFT).
Principales resultados:
- Aislamiento del primer monómero estable de dos coordenadas de paladio (((0) bis-isocianuro, Pd (((CNAr (((Dipp2)) (((2).
- Demostración del intercambio rápido de ligandos sin formación de tris-isocianuro.
- Pd ((CNAr ((Dipp2)) exhibe actividad en adición oxidativa (por ejemplo, con cloruro de bencilo, bromuro de mesitilo) y en las reacciones de acoplamiento cruzado Suzuki-Miyaura.
- Reacciones únicas con talio (I) triflato, oxígeno (formando un complejo peroxo) y nitrosobenzeno (formando un complejo Pd (II)).
Conclusiones:
- Pd ((CNAr ((Dipp2)) representa un avance significativo en la química del paladio de baja coordenada estable.
- El complejo sirve como un catalizador eficaz para importantes transformaciones orgánicas.
- La reactividad inusual, que incluye un cambio de valencia formal en la reacción con nitrosobenzeno, destaca la naturaleza electrónica única del complejo.
Videos de Conceptos Relacionados
00:57Cationic Chain-Growth Polymerization: Mechanism
The cationic polymerization mechanism consists of three steps: initiation, propagation, and termination. In the initiation step of the polymerization process, the π bond of a monomer gets protonated by the Lewis acid catalyst, which is formed from boron trifluoride and water. The protonation of the π bond generates a carbocation stabilized by the electron‐donating group. In the propagation step, the π bond of the second monomer acts as a nucleophile and attacks the generated carbocation,...
01:20Anionic Chain-Growth Polymerization: Overview
The polymerization process that involves carbanion as an intermediate is called anionic polymerization. It is also a type of addition or chain-growth polymerization. Anionic polymerization gets initiated by a strong nucleophile such as an organolithium or a Grignard reagent. The most commonly used initiator for anionic polymerization is butyl lithium. Monomers involved in anionic polymerization must possess a vinyl group bonded to one or two electron-withdrawing groups. For instance,...
01:16Cycloaddition Reactions: MO Requirements for Thermal Activation
Thermal cycloadditions are reactions where the source of activation energy needed to initiate the reaction is provided in the form of heat. A typical example of a thermally-allowed cycloaddition is the Diels–Alder reaction, which is a [4 + 2] cycloaddition. In contrast, a [2 + 2] cycloaddition is thermally forbidden.
01:04Anionic Chain-Growth Polymerization: Mechanism
The mechanism for anionic chain-growth polymerization involves initiation, propagation, and termination steps. In the initiation step, a nucleophilic anion, such as butyl lithium, initiates the polymerization process by attacking the π bond of the vinylic monomer. As a result, a carbanion, stabilized by the electron‐withdrawing group, is generated. The resulting carbanion acts as a Michael donor in the propagation step and attacks the second vinylic monomer, which acts as a Michael acceptor.
01:14Electrophilic 1,2- and 1,4-Addition of X2 to 1,3-Butadiene
Electrophilic addition of halogens to alkenes proceeds via a cyclic halonium ion to form a 1,2-dihalide or a vicinal dihalide.
![[4+2] Cycloaddition of Conjugated Dienes: Diels–Alder Reaction](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2Ffiles%2Fmedia%2Fscience-education%2Fscience-education-thumbs%2F12417.jpg&w=3840&q=75)
01:16[4+2] Cycloaddition of Conjugated Dienes: Diels–Alder Reaction
The Diels–Alder reaction is an example of a thermal pericyclic reaction between a conjugated diene and an alkene or alkyne, commonly referred to as a dienophile. The reaction involves a concerted movement of six π electrons, four from the diene and two from the dienophile, forming an unsaturated six-membered ring. As a result, these reactions are classified as [4+2] cycloadditions.