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相关概念视频

Photochemical Electrocyclic Reactions: Stereochemistry01:26

Photochemical Electrocyclic Reactions: Stereochemistry

1.9K
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
1.9K
Thermal and Photochemical Electrocyclic Reactions: Overview01:26

Thermal and Photochemical Electrocyclic Reactions: Overview

2.5K
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.
2.5K
Pericyclic Reactions: Introduction01:17

Pericyclic Reactions: Introduction

8.6K
Pericyclic reactions are organic reactions that occur via a concerted mechanism without generating any intermediates. The reactions proceed through the movement of electrons in a closed loop to form a cyclic transition state, where rearrangement of the σ and π bonds yields specific products.
Pericyclic reactions can be classified into three categories: electrocyclic reactions, cycloaddition reactions, and sigmatropic rearrangements. Electrocyclic reactions and sigmatropic...
8.6K
Thermal Electrocyclic Reactions: Stereochemistry01:17

Thermal Electrocyclic Reactions: Stereochemistry

2.1K
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.
2.1K
π Molecular Orbitals of 1,3-Butadiene01:24

π Molecular Orbitals of 1,3-Butadiene

10.2K
Conjugated dienes have lower heats of hydrogenation than cumulated and isolated dienes, making them more stable. The enhanced stabilization of conjugated systems can be understood from their π molecular orbitals.
The simplest conjugated diene is 1,3-butadiene: a four-carbon system where each carbon is sp2-hybridized and has an unhybridized p orbital that contains an unpaired electron. According to molecular orbital theory, atomic orbitals combine to form molecular orbitals such that the number...
10.2K
Stability of Conjugated Dienes01:28

Stability of Conjugated Dienes

3.8K
Introduction
A comparison of the enthalpies of hydrogenation of dienes reveals that conjugated dienes release less heat on hydrogenation, rendering them more stable than their nonconjugated analogs.
3.8K

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Updated: Oct 9, 2025

Effect of Bending on the Electrical Characteristics of Flexible Organic Single Crystal-based Field-effect Transistors
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Effect of Bending on the Electrical Characteristics of Flexible Organic Single Crystal-based Field-effect Transistors

Published on: November 7, 2016

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高性能有机电子材料通过扭曲二胺

Cedric Schaack1, Austin M Evans1, Fay Ng1

  • 1Department of Chemistry, Columbia University, Havemeyer Mail Code 3130, 3000 Broadway, New York, New York 10027, United States.

Journal of the American Chemical Society
|December 23, 2021
PubMed
概括

将平面二烯二胺 (PDI) 分子扭曲成3D形状可以增强有机电子设备. 这种结构修改通过改变光学和电子特性来提高光伏,光探测器和电池的性能.

科学领域:

  • 有机电子材料科学
  • 先进的功能性有机分子

背景情况:

  • 二胺 (PDI) 是有机电子的基本组成部分.
  • 传统的PDI设计侧重于平面结构,以促进对面堆叠.
  • 现有的PDI架构限制了设备的性能潜力.

研究的目的:

  • 探索PDI核心对材料性能和设备性能的影响.
  • 在基于PDI的系统中展示引入扭曲的可靠方法.
  • 为下一代有机电子产品展示3D PDI结构的潜力.

主要方法:

  • 合成和描述扭曲的PDI分子,寡合物和聚合物.
  • 研究这些扭曲材料的结构特性关系.
  • 制造和测试包含扭曲的PDI的有机电子设备.

主要成果:

  • 与平面类型相比,扭曲的PDI具有独特的光学和电子特性.
  • 碗形的扭曲会产生高效的单片裂变材料.
  • 像一样的扭曲会产生强烈的棉花效应.
  • 3D PDI结构显著提高了有机光伏,光探测器和电池的性能.

结论:

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Using Cyclic Voltammetry, UV-Vis-NIR, and EPR Spectroelectrochemistry to Analyze Organic Compounds
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Low Pressure Vapor-assisted Solution Process for Tunable Band Gap Pinhole-free Methylammonium Lead Halide Perovskite Films
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Using Cyclic Voltammetry, UV-Vis-NIR, and EPR Spectroelectrochemistry to Analyze Organic Compounds
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Using Cyclic Voltammetry, UV-Vis-NIR, and EPR Spectroelectrochemistry to Analyze Organic Compounds

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Low Pressure Vapor-assisted Solution Process for Tunable Band Gap Pinhole-free Methylammonium Lead Halide Perovskite Films
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  • 非平面,扭曲的PDI结构提供了卓越的光电子特性.
  • 扭曲的PDI的三维性质是提高设备性能的关键.
  • 这项研究为设计高性能有机电子材料开辟了新的途径.