Jove
Visualize
联系我们

相关概念视频

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

您也可能阅读

相关文章

通过共同作者、期刊和引用图与本文相关的文章。

排序
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
关于 JoVE
概览领导团队博客JoVE 帮助中心
作者
出版流程编辑委员会范围与政策同行评审常见问题投稿
图书馆员
用户评价订阅访问资源图书馆顾问委员会常见问题
研究
JoVE JournalMethods CollectionsJoVE Encyclopedia of Experiments存档
教育
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab Manual教师资源中心教师网站
使用条款与条件
隐私政策
政策

相关实验视频

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

基于二甲的分子结合中的高效光开关

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
概括

沉积了薄薄的二甲基乙烯聚合物,形成了分子结. 这些结点在光诱导切换时显示出显著的导电性变化,证明了分子电子的潜力.

科学领域:

  • 材料科学
  • 分子电子
  • 有机化学

背景情况:

  • 乙烯寡聚物 (Oligo(DAE)) 是光色分子,在分子电子学中具有潜在的应用.
  • 控制分子结合的导电性对于设备的开发至关重要.

研究的目的:

  • 制造和特征固态分子连接使用薄层的diarylethene oligomers.
  • 为了研究这些分子结合的光交换导率.

主要方法:

  • 在玻璃碳和黄金电极上电化学沉积.
  • 使用电化学,XPS和AFM进行表征.
  • 用C-AFM尖端和不同层厚度 (2-3 nm和8-9 nm) 制造分子连接.

主要成果:

  • 成功地沉积和特征化的薄层.
  • 在开放式 (高度电阻) 和封闭式 (导电性) 之间进行光诱导的切换.
  • 在3纳米连接处实现了2-3的ON/OFF比,在9纳米连接处达到200-400的比.

结论:

  • 乙烯寡合物分子连接具有可光切换导电性.
  • 接口厚度会影响开启/关闭的比率,更厚的接口会显示出更高的比率.

更多相关视频

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

相关实验视频

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
  • 在分子开关和记忆器件中的应用方面,Oligo (DAE) 分子连接具有前景.