Video Experimental Relacionado
Updated: Feb 2, 2026
10:00
Hydrogen Production and Utilization in a Membrane Reactor
Published on: March 10, 2023
3.2K
Trans-hidrogenación, gem-hidrogenación y trans-hidrometalización de las alquinas: un informe provisional sobre un
1Max-Planck-Institut für Kohlenforschung , D-45470 Mülheim /Ruhr, Germany.
Journal of the American Chemical Society
|November 14, 2018
Resumen
Los catalizadores de rutenio permiten la transhidrogenación directa de los alquinos, formando E-alquenos. Una nueva vía de hidrogenación de gemas también crea complejos de carbenos metálicos, expandiendo las posibilidades catalíticas.
Área de la Ciencia:
- Química organometálica
- Catálisis
- Síntesis orgánica
Sus antecedentes:
- La hidrogenación tradicional catalizada por metales incluye la entrega cis de H2 a sustratos insaturados.
- Este estudio desafía el mecanismo canónico de cis-adición en la semirreducción de alquinos.
Objetivo del estudio:
- Investigar las vías de hidrogenación no convencionales utilizando catalizadores basados en [Cp*Ru].
- Explorar nuevos modos de reactividad, incluida la hidrogenación de gemas y la transhidrogenación de alquinas.
- Demostrar la aplicabilidad más amplia de estos principios en reacciones de transición relacionadas.
Principales métodos:
- Se han utilizado catalizadores basados en [Cp*Ru] para las transformaciones de alquinos.
- Estudios computacionales empleados para aclarar los mecanismos y las barreras de reacción.
- Se han investigado las reacciones de transhidroboración, transhidrosilación, transhidrogemilación y transhidrostanciación.
Principales resultados:
- Descubrió la trans-hidrogenación directa de alquinas internas que producen E-alquenos a través de σ-complejos y metaciclopropenos.
- Identificó una nueva vía de hidrogenación de gemas donde ambos átomos de H se agregan a un solo carbono, formando complejos de carbenos metálicos.
- Se han demostrado barreras energéticas similares para las vías trans y gem, con una selectividad controlable por sustituyentes polares.
- Se extendió el principio de la trans-adición a la hidroboración, la hidrosilación, la hidrogermilación y la hidrostanciación.
Conclusiones:
- La transhidrogenación catalítica y la hidrogenación de gemas representan transformaciones fundamentalmente nuevas en la química organometálica.
- Estas reacciones robustas exhiben una excelente compatibilidad de grupo funcional y han demostrado ser efectivas en la síntesis de productos naturales complejos.
- Los principios subyacentes de la transición son aplicables a través de una serie de procesos catalíticos relacionados.
Más Videos Relacionados
Videos de Conceptos Relacionados
00:26Hydrogen Bonds
133.3K
Hydrogen bonds are weak attractions between atoms that have formed other chemical bonds. One of these atoms is electronegative, like oxygen, and has a partial negative charge. The other is a hydrogen atom that has bonded with another electronegative atom and has a partial positive charge.
Hydrogen Bonds Control the World!
Because hydrogen has very weak electronegativity when it binds with a strongly electronegative atom, such as oxygen or nitrogen, electrons in the bond are unequally shared....
Hydrogen Bonds Control the World!
Because hydrogen has very weak electronegativity when it binds with a strongly electronegative atom, such as oxygen or nitrogen, electrons in the bond are unequally shared....
133.3K
01:04Hydrogen Bonds
14.4K
A hydrogen bond is formed when a weakly positive hydrogen atom already bonded to one electronegative atom (for example, the oxygen in the water molecule) is attracted to another electronegative atom from another polar molecule, such as water (H2O), hydrogen fluoride (HF), or ammonia (NH3). The huge electronegativity difference between the H atom (2.1) and the atom to which it is bonded (4.0 for an F atom, 3.5 for an O atom, or 3.0 for an N atom), combined with the very small size of an H atom...
14.4K
02:10Reduction of Alkynes to trans-Alkenes: Sodium in Liquid Ammonia
10.6K
Alkynes can be reduced to trans-alkenes using sodium or lithium in liquid ammonia. The reaction, known as dissolving metal reduction, proceeds with an anti addition of hydrogen across the carbon–carbon triple bond to form the trans product. Since ammonia exists as a gas (bp = −33°C) at room temperature, the reaction is carried out at low temperatures using a mixture of dry ice (sublimes at −78°C) and acetone.
When dissolved in liquid ammonia, an alkali metal, such as sodium,...
When dissolved in liquid ammonia, an alkali metal, such as sodium,...
10.6K
02:24Reduction of Alkynes to cis-Alkenes: Catalytic Hydrogenation
9.1K
Introduction
Like alkenes, alkynes can be reduced to alkanes in the presence of transition metal catalysts such as Pt, Pd, or Ni. The reaction involves two sequential syn additions of hydrogen via a cis-alkene intermediate.
Like alkenes, alkynes can be reduced to alkanes in the presence of transition metal catalysts such as Pt, Pd, or Ni. The reaction involves two sequential syn additions of hydrogen via a cis-alkene intermediate.
9.1K
02:37Disubstituted Cyclohexanes: cis-trans Isomerism
14.2K
Depending upon the different spatial orientation of the substituents, the disubstituted cycloalkanes exhibit two types of stereoisomers. The cis isomers have the substituents on the same side of the ring, whereas the trans isomers have the substituents on the opposite sides. These stereoisomers exhibit different physical properties and cannot be interconverted without breaking the carbon-carbon bonds.
In cyclohexane, the substituents can occupy different positions generating distinct isomers....
In cyclohexane, the substituents can occupy different positions generating distinct isomers....
14.2K
02:13Reduction of Alkenes: Catalytic Hydrogenation
14.1K
Alkenes undergo reduction by the addition of molecular hydrogen to give alkanes. Because the process generally occurs in the presence of a transition-metal catalyst, the reaction is called catalytic hydrogenation.
Metals like palladium, platinum, and nickel are commonly used in their solid forms — fine powder on an inert surface. As these catalysts remain insoluble in the reaction mixture, they are referred to as heterogeneous catalysts.
The hydrogenation process takes place on the...
Metals like palladium, platinum, and nickel are commonly used in their solid forms — fine powder on an inert surface. As these catalysts remain insoluble in the reaction mixture, they are referred to as heterogeneous catalysts.
The hydrogenation process takes place on the...
14.1K