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Updated: May 19, 2026
09:26
Synthesis and Characterization of Supramolecular Colloids
Published on: April 22, 2016
多乙烯六边形的光触发可逆的超分子转化
Shangjun Chen1, Li-Jun Chen, Hai-Bo Yang
1Key Laboratory for Advanced Materials and Institute of Fine Chemicals, East China University of Science and Technology, Shanghai 200237, PR China.
Journal of the American Chemical Society
|August 14, 2012
概括
研究人员使用自组装创建了新的光色六角形. 这些超分子结构精确地控制形状,大小和光色单元,使可逆光触发转变成为可能.
科学领域:
- 超分子化学 超分子化学
- 材料科学 材料科学 材料科学
- 摄影化学的使用.
背景情况:
- 控制人工超分子中的结构转变是很困难的.
- 开发响应性和精确设计的超分子系统是一个关键的挑战.
研究的目的:
- 构建一个新的多乙烯六角形家族.
- 为了实现对形状,尺寸和光色单位数量的精确控制.
- 开发具有光响应性质的超分子系统.
主要方法:
- 采用了协调驱动的自组装.
- 合成多乙烯基乙烯构建块.
- 由此产生的高分子六角形的特征.
主要成果:
- 一个新的多乙烯六边形家族成功构建.
- 对六角形状,尺寸和光色单元的整合实现了精确的控制.
- 六角动物表现出对光刺激的高度敏感性和响应性.
结论:
- 开发的多乙烯六边形可以精确控制超分子结构.
- 这些系统允许由光照射引发的定量,可逆转换.
- 这项工作推动了对光敏感的人造超分子材料的设计.
相关概念视频
01:26Thermal and Photochemical Electrocyclic Reactions: Overview
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.
01:26Photochemical Electrocyclic Reactions: Stereochemistry
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
Selection Rules: Photochemical Activation
01:12Cycloaddition Reactions: MO Requirements for Photochemical Activation
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.
01:17Thermal Electrocyclic Reactions: Stereochemistry
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.
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.
![[3,3] Sigmatropic Rearrangement of 1,5-Dienes: Cope Rearrangement](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2Ffiles%2Fmedia%2Fscience-education%2Fscience-education-thumbs%2F12422.jpg&w=3840&q=75)
01:21[3,3] Sigmatropic Rearrangement of 1,5-Dienes: Cope Rearrangement
The Cope rearrangement is classified as a [3,3] sigmatropic shift in 1,5-dienes, leading to a more stable, isomeric 1,5-diene. The reaction involves a concerted movement of six electrons, four from two π bonds and two from a σ bond, via an energetically favorable chair-like transition state.
![[4+2] Cycloaddition of Conjugated Dienes: Diels–Alder Reaction](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2Ffiles%2Fmedia%2Fscience-education%2Fscience-education-thumbs%2F12417.jpg&w=3840&q=75)
01:16[4+2] Cycloaddition of Conjugated Dienes: Diels–Alder Reaction
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.