Jove
Visualize
Contáctanos

Videos de Conceptos Relacionados

Photochemical Electrocyclic Reactions: Stereochemistry01:26

Photochemical Electrocyclic Reactions: Stereochemistry

2.1K
The absorption of UV–visible light by conjugated systems causes the promotion of an electron from the ground state to the excited state. Consequently, photochemical electrocyclic reactions proceed via the excited-state HOMO rather than the ground-state HOMO. Since the ground- and excited-state HOMOs have different symmetries, the stereochemical outcome of electrocyclic reactions depends on the mode of activation; i.e., thermal or photochemical.
Selection Rules: Photochemical Activation
2.1K
Thermal and Photochemical Electrocyclic Reactions: Overview01:26

Thermal and Photochemical Electrocyclic Reactions: Overview

2.8K
Electrocyclic reactions are reversible reactions. They involve an intramolecular cyclization or ring-opening of a conjugated polyene. Shown below are two examples of electrocyclic reactions. In the first reaction, the formation of the cyclic product is favored. In contrast, in the second reaction, ring-opening is favored due to the high ring strain associated with cyclobutene formation.
2.8K
Cycloaddition Reactions: MO Requirements for Photochemical Activation01:12

Cycloaddition Reactions: MO Requirements for Photochemical Activation

2.5K
Some cycloaddition reactions are activated by heat, while others are initiated by light. For example, a [2 + 2] cycloaddition between two ethylene molecules occurs only in the presence of light. It is photochemically allowed but thermally forbidden.
2.5K
Diels–Alder Reaction Forming Bridged Bicyclic Products: Stereochemistry01:29

Diels–Alder Reaction Forming Bridged Bicyclic Products: Stereochemistry

5.3K
Diels–Alder reactions between cyclic dienes locked in an s-cis configuration and dienophiles yield bridged bicyclic products.
5.3K
[4+2] Cycloaddition of Conjugated Dienes: Diels–Alder Reaction01:16

[4+2] Cycloaddition of Conjugated Dienes: Diels–Alder Reaction

12.0K
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.
12.0K
Thermal Electrocyclic Reactions: Stereochemistry01:17

Thermal Electrocyclic Reactions: Stereochemistry

2.4K
The stereochemistry of electrocyclic reactions is strongly influenced by the orbital symmetry of the polyene HOMO. Under thermal conditions, the reaction proceeds via the ground-state HOMO.
Selection Rules: Thermal Activation
Conjugated systems containing an even number of π-electron pairs undergo a conrotatory ring closure. For example, thermal electrocyclization of (2E,4E)-2,4-hexadiene, a conjugated diene containing two π-electron pairs, gives trans-3,4-dimethylcyclobutene.
2.4K

También podría leer

Artículos Relacionados

Artículos vinculados a este trabajo por autores compartidos, revista y gráfico de citas.

Ordenar por
Same author

Hybrid Plasmonic Nanostructures Using π-Conjugated Systems for Molecularly Imprinted Polymers.

Nano letters·2026
Same author

Synthesis, Photophysical, and Chiroptical Properties of Optically Active BINOL-Boranil Enantiomers.

ACS omega·2026
Same author

Reversible Self-assembly of a Viologen-based Supramolecular Gel Network under Electrochemical Control.

Chemistry (Weinheim an der Bergstrasse, Germany)·2025
Same author

Two-State, Nonvolatile Memristors and Light-Assisted Logic-In Operation from Diarylethene-Based Single-Molecule Junctions.

Journal of the American Chemical Society·2025
Same author

Synthesis, Photophysical Properties, and Ab Initio Calculations of Dual Solution-Solid-State-Emitting Ethynyl-Extended Boranil Complexes.

The Journal of organic chemistry·2025
Same author

π-Expansion as gateway to viologen-based pimers.

Chemical science·2025
JoVE
x logofacebook logolinkedin logoyoutube logo
ACERCA DE JoVE
Visión GeneralLiderazgoBlogCentro de Ayuda JoVE
AUTORES
Proceso de PublicaciónConsejo EditorialAlcance y PolíticasRevisión por ParesPreguntas FrecuentesEnviar
BIBLIOTECARIOS
TestimoniosSuscripcionesAccesoRecursosConsejo Asesor de BibliotecasPreguntas Frecuentes
INVESTIGACIÓN
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchivo
EDUCACIÓN
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualCentro de Recursos para ProfesoresSitio de Profesores
Términos y Condiciones de Uso
Política de Privacidad
Políticas

Video Experimental Relacionado

Updated: Dec 24, 2025

Determination of the Photoisomerization Quantum Yield of a Hydrazone Photoswitch
09:33

Determination of the Photoisomerization Quantum Yield of a Hydrazone Photoswitch

Published on: February 7, 2022

3.8K

Fotointerruptor de alta eficiencia en las uniones moleculares basadas en diarilethene

Imen Hnid1, Denis Frath1, Frederic Lafolet1

  • 1Université de Paris, ITODYS, CNRS, UMR 7086, 15 rue J-A de Baïf, 75205 Paris Cedex 13, France.

Journal of the American Chemical Society
|April 14, 2020
PubMed
Resumen

Se depositaron finas capas de oligómeros de diarileteno y se formaron uniones moleculares. Estas uniones mostraron cambios significativos de conductividad en la conmutación inducida por la luz, lo que demuestra el potencial de la electrónica molecular.

Más Videos Relacionados

A 'Plug and Play' Method to Create Water-dispersible Nanoassemblies Containing an Amphiphilic Polymer, Organic Dyes and Upconverting Nanoparticles
12:51

A 'Plug and Play' Method to Create Water-dispersible Nanoassemblies Containing an Amphiphilic Polymer, Organic Dyes and Upconverting Nanoparticles

Published on: November 14, 2015

10.3K
Novel Techniques for Observing Structural Dynamics of Photoresponsive Liquid Crystals
10:35

Novel Techniques for Observing Structural Dynamics of Photoresponsive Liquid Crystals

Published on: May 29, 2018

9.1K

Videos de Experimentos Relacionados

Last Updated: Dec 24, 2025

Determination of the Photoisomerization Quantum Yield of a Hydrazone Photoswitch
09:33

Determination of the Photoisomerization Quantum Yield of a Hydrazone Photoswitch

Published on: February 7, 2022

3.8K
A 'Plug and Play' Method to Create Water-dispersible Nanoassemblies Containing an Amphiphilic Polymer, Organic Dyes and Upconverting Nanoparticles
12:51

A 'Plug and Play' Method to Create Water-dispersible Nanoassemblies Containing an Amphiphilic Polymer, Organic Dyes and Upconverting Nanoparticles

Published on: November 14, 2015

10.3K
Novel Techniques for Observing Structural Dynamics of Photoresponsive Liquid Crystals
10:35

Novel Techniques for Observing Structural Dynamics of Photoresponsive Liquid Crystals

Published on: May 29, 2018

9.1K

Área de la Ciencia:

  • Ciencias de los materiales
  • La electrónica molecular
  • Química orgánica

Sus antecedentes:

  • Los oligómeros de diarileteno (oligo ((DAE)) son moléculas fotocrómicas con aplicaciones potenciales en la electrónica molecular.
  • El control de la conductividad en las uniones moleculares es crucial para el desarrollo de dispositivos.

Objetivo del estudio:

  • Fabricar y caracterizar las uniones moleculares en estado sólido utilizando finas capas de oligómeros de diarileteno.
  • Para investigar la conductividad fotoswitchable de estas uniones moleculares.

Principales métodos:

  • Deposición electroquímica de oligo (DAE) en electrodos de carbono vidrioso y oro.
  • Caracterización mediante electroquímica, XPS y AFM.
  • Fabricación de uniones moleculares con puntas C-AFM y diferentes espesores de capa (2-3 nm y 8-9 nm).

Principales resultados:

  • El éxito de la deposición y la caracterización de las capas delgadas de oligo (DAE).
  • Se ha demostrado la conmutación inducida por la luz entre formas abiertas (altamente resistentes) y cerradas (conductivas).
  • Se logran relaciones de encendido/apagado de 2-3 para las uniones de 3 nm y de 200-400 para las uniones de 9 nm.

Conclusiones:

  • Las uniones moleculares de oligómeros de diarileno exhiben una conductividad fotointercambiable.
  • El grosor de las uniones influye en la relación encendido/apagado, y las uniones más gruesas muestran proporciones más altas.
  • Las uniones moleculares de oligo ((DAE) son prometedoras para aplicaciones en interruptores moleculares y dispositivos de memoria.