Video Experimental Relacionado
Updated: Jun 9, 2026
06:44
From Molecules to Materials: Engineering New Ionic Liquid Crystals Through Halogen Bonding
Published on: March 24, 2018
Mecanismo de la halogenación selectiva por SyrB2: un estudio computacional de estudio
Tomasz Borowski1, Holger Noack, Mariusz Radoń
1Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, ul. Niezapominajek 8, 30-239 Kraków, Poland. ncborows@cyf-kr.edu.pl
Journal of the American Chemical Society
|August 27, 2010
Resumen
Los estudios computacionales revelan que la halogenasa SyrB2 utiliza estereoisómeros de una especie de oxoferril en la cloración. El mecanismo de reacción implica la escisión de C-H y la transferencia rápida de ligandos, favoreciendo la cloración para el sustrato nativo.
Área de la Ciencia:
- La bioquímica es la bioquímica.
- Química computacional es la química computacional.
- Enzimología Enzimología.
Sus antecedentes:
- Las halogenasas dependientes del α-cetoglutarato son enzimas que catalizan las reacciones de cloración.
- SyrB2 es una enzima representativa en esta clase, crucial para la comprensión de los mecanismos de la halogenasa.
Objetivo del estudio:
- Para dilucidar el mecanismo de reacción de la cloración de SyrB2 utilizando métodos computacionales.
- Para identificar la naturaleza de las especies de oxoferril experimentalmente observadas.
Principales métodos:
- Modelado macromolecular utilizando acoplamiento molecular.
- Investigaciones de la Teoría Funcional de la Densidad (DFT).
- Cálculos CASPT2 para el análisis del estado de giro.
Principales resultados:
- Se identificaron dos especies de oxoferril como estereoisómeros que difieren en la coordinación de ligandos.
- Ambos estereoisómeros Fe(IV) O se descomponen en radicales intermedios Fe(III) Cl(OH) /carbono a través de la escisión del enlace C-H.
- Se determinó que la transferencia de ligando en el paso de rebote es rápida y dependiente del sustrato, favoreciendo la cloración para L-Thr.
Conclusiones:
- El mecanismo de cloración incluye intermediarios estereoisoméricos Fe(IV) O.
- La reacción continúa en la superficie de energía potencial del quinteto después de la formación de Fe(IV) O.
- La estereoquímica y la proximidad del ligando dictan la eficiencia de la cloración.
![The Synthesis of [Sn10(Si(SiMe3)3)4]2- Using a Metastable Sn(I) Halide Solution Synthesized via a Co-condensation Technique](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F54498.jpg&w=3840&q=50)
Videos de Conceptos Relacionados
02:36Regioselectivity and Stereochemistry of Hydroboration
A significant aspect of hydroboration–oxidation is the regio- and stereochemical outcome of the reaction.
Hydroboration proceeds in a concerted fashion with the attack of borane on the π bond, giving a cyclic four-centered transition state. The –BH2 group is bonded to the less substituted carbon and –H to the more substituted carbon. The concerted nature requires the simultaneous addition of –H and –BH2 across the same face of the alkene giving syn stereochemistry.
Hydroboration proceeds in a concerted fashion with the attack of borane on the π bond, giving a cyclic four-centered transition state. The –BH2 group is bonded to the less substituted carbon and –H to the more substituted carbon. The concerted nature requires the simultaneous addition of –H and –BH2 across the same face of the alkene giving syn stereochemistry.
02:46Halogenation of Alkenes
Halogenation is the addition of chlorine or bromine across the double bond in an alkene to yield a vicinal dihalide. The reaction occurs in the presence of inert and non-nucleophilic solvents, such as methylene chloride, chloroform, or carbon tetrachloride.
Consider the bromination of cyclopentene. Molecular bromine is polarized in the proximity of the π electrons of cyclopentene. An electrophilic bromine atom adds across the double bond, forming a cyclic bromonium ion intermediate.
Consider the bromination of cyclopentene. Molecular bromine is polarized in the proximity of the π electrons of cyclopentene. An electrophilic bromine atom adds across the double bond, forming a cyclic bromonium ion intermediate.
02:17Regioselectivity of Electrophilic Additions to Alkenes: Markovnikov's Rule
If a set of reactants can yield multiple constitutional isomers, but one of the isomers is obtained as the major product, the reaction is said to be regioselective. In such reactions, bond formation or breaking is favored at one reaction site over others.
The hydrohalogenation of an unsymmetrical alkene can yield two haloalkane products, depending on which vinylic carbon takes up the halogen. However, one product usually predominates, where hydrogen adds to the vinylic carbon bearing the...
The hydrohalogenation of an unsymmetrical alkene can yield two haloalkane products, depending on which vinylic carbon takes up the halogen. However, one product usually predominates, where hydrogen adds to the vinylic carbon bearing the...
01:26Radical Substitution: Hydrogenolysis of Alkyl Halides with Tributyltin Hydride
Radical substitution reactions can be used to remove functional groups from molecules. The hydrogenolysis of alkyl halides is one such reaction, where the weak Sn–H bond in tributyltin hydride reacts with alkyl halides to form alkanes. Here, the reagent Bu3SnH yields tributyltin halide as a byproduct.
The bonds formed in this reaction are stronger than the bonds broken, making it energetically favorable. The reaction follows a radical chain mechanism similar to radical halogenation reactions,...
The bonds formed in this reaction are stronger than the bonds broken, making it energetically favorable. The reaction follows a radical chain mechanism similar to radical halogenation reactions,...
02:26Preparation and Reactions of Sulfides
Sulfides are the sulfur analog of ethers, just as thiols are the sulfur analog of alcohol. Like ethers, sulfides also consist of two hydrocarbon groups bonded to the central sulfur atom. Depending upon the type of groups present, sulfides can be symmetrical or asymmetrical. Symmetrical sulfides can be prepared via an SN2 reaction between 2 equivalents of an alkyl halide and one equivalent of sodium sulfide.
02:26SN2 Reaction: Transition State
An SN2 reaction of an alkyl halide is a single-step process in which bond formation between the nucleophile and the substrate and bond breaking between the substrate and the halide occurs simultaneously through a transition state without forming an intermediate.
When the nucleophile approaches the electrophilic carbon with its lone pairs, the halide acts as a leaving group and moves away with the electron-pair bonded to the carbon. Dotted partial bonds represent the bonds being formed or broken...
When the nucleophile approaches the electrophilic carbon with its lone pairs, the halide acts as a leaving group and moves away with the electron-pair bonded to the carbon. Dotted partial bonds represent the bonds being formed or broken...