Video Experimental Relacionado
Updated: Jun 30, 2026
09:53
Predicting Catalyst Extrudate Breakage Based on the Modulus of Rupture
Published on: May 13, 2018
Conocimiento mecanicista de las reacciones de fragmentación de los complejos de titanapinacolato
Jesudoss V Kingston1, Oleg V Ozerov, Sean Parkin
1Department of Chemistry, University of Kentucky, Lexington, Kentucky 40506-0055, USA.
Journal of the American Chemical Society
|October 10, 2002
Resumen
Los complejos de titanapinacolato se someten a reacciones de escisión de enlaces C-C con alquinos y cetonas. La fragmentación se produce a través de la disociación reversible, seguida de una reacción con el sustrato, ofreciendo información sobre las reacciones de formación de enlaces C-C.
Área de la Ciencia:
- Química organometálica Química orgánica de los metales.
- Los complejos de titanio son complejos de titanio.
- Mecanismos de reacción Mecanismos de reacción
Sus antecedentes:
- Los intermediarios metallapinacolatos son cruciales en las reacciones de formación de enlaces C-C como el acoplamiento pinacol y la química McMurry.
- Los complejos de titanapinacolatos, específicamente (DMSC) Ti ((OCAr ((2) Car ((2) O), se investigan por su reactividad.
Objetivo del estudio:
- Para investigar las reacciones entre los complejos de titanapinacolate y las alquinas terminales o cetonas aromáticas.
- Para dilucidar el mecanismo de las reacciones de fragmentación de los complejos de titanapinacolate.
Principales métodos:
- Síntesis y caracterización de complejos de titanapinacolate utilizando métodos espectroscópicos y cristalografía de rayos X.
- Análisis cinético de la reacción entre un complejo específico de titanapinacolate y un alquino.
Principales resultados:
- Las reacciones implican la ruptura del enlace C-C del titanaciclo, produciendo complejos del oxatitanaciclo y cetona libre.
- Los estudios cinéticos indican un mecanismo de preequilibrio que implica la disociación reversible del complejo de titanapinacolate.
- Caracterización de los nuevos complejos 2-oxatitanaciclopent-4-eno y 2-oxatitanacicloheptadieno.
Conclusiones:
- Los complejos de titanapinacolate se fragmentan a través de un mecanismo de preequilibrio, disuadiéndose en especies reactivas de titanio.
- Esta vía de fragmentación proporciona conocimientos mecanicistas relevantes para la formación de enlaces C-C mediados por metallapinacolate.
- El estudio amplía la comprensión de las transformaciones orgánicas mediadas por el titanio.
Videos de Conceptos Relacionados
03:06Reaction Mechanisms
Chemical reactions often occur in a stepwise fashion, involving two or more distinct reactions taking place in a sequence. A balanced equation indicates the reacting species and the product species, but it reveals no details about how the reaction occurs at the molecular level. The reaction mechanism (or reaction path) provides details regarding the precise, step-by-step process by which a reaction occurs.
For instance, the decomposition of ozone appears to follow a mechanism with two steps:
For instance, the decomposition of ozone appears to follow a mechanism with two steps:
02:35Free-Radical Chain Reaction and Polymerization of Alkenes
The conversion of alkenes to macromolecules called polymers is a reaction of high commercial importance. The structure of the polymer is defined by a repeating unit, while the terminal groups are considered insignificant. The average degree of polymerization represents the number of repeating units in the polymer molecule and is denoted by the subscript n.
01:20Mass Spectrometry: Molecular Fragmentation Overview
The ionization of a molecule into a molecular ion inside the mass spectrometer causes instability in the molecule's structure due to the loss of an electron. This eventually leads to the fragmentation or breaking of some bonds in the molecule. The fragmentation occurs predominantly at specific bonds to yield relatively stable fragments.
One type of fragmentation pattern is the cleavage of a single bond in the molecular ion. The cleavage leads to a radical and a cation. The cleavage can occur at...
One type of fragmentation pattern is the cleavage of a single bond in the molecular ion. The cleavage leads to a radical and a cation. The cleavage can occur at...
01:13Olefin Metathesis Polymerization: Overview
Recently, the development of olefin metathesis polymerization advanced the field of polymer synthesis. Simply put, the reorganization of substituents on their double bonds between two olefins in the presence of a catalyst is known as the olefin metathesis reaction. The use of metathesis reaction for polymer synthesis is called olefin metathesis polymerization.
Ruthenium-based Grubbs catalyst is the most commonly used catalyst for olefin metathesis polymerization. Grubbs catalyst consists of a...
Ruthenium-based Grubbs catalyst is the most commonly used catalyst for olefin metathesis polymerization. Grubbs catalyst consists of a...
01:23Mass Spectrometry: Aromatic Compound Fragmentation
Upon ionization, aromatic compounds generate a molecular ion that is observed as a prominent peak in their mass spectra. For example, the molecular ion peak for benzene appears at a mass-to-charge ratio of 78, while toluene is observed at a mass-to-charge ratio of 92. The molecular ion benzene is highly stable and does not readily undergo further fragmentation due to the significant amount of energy required to disrupt the aromatic stability of the benzene ring. In contrast, the molecular ion...
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.