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Updated: Jun 10, 2025

Reactive Vapor Deposition of Conjugated Polymer Films on Arbitrary Substrates
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Published on: January 17, 2018

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立或躺的thiophene在表面上决定了反应的差异

Hongchao Wang1,2,3, Youjie Wang4, Caiyan Zheng4

  • 1School of Chemical Engineering and Technology, Tianjin University, Tianjin 300350, People's Republic of China.

The journal of physical chemistry letters
|October 14, 2024
PubMed
概括

2,3,4,5-tetrabromothiophene在金属表面的吸附配置决定了反应结果. 选择不同的金属基板可以控制分子方向,影响表面反应和材料合成.

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Thermal Electrocyclic Reactions: Stereochemistry

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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.
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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.
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Sigmatropic rearrangements are a class of pericyclic reactions in which a σ bond migrates from one part of a π system to another. These are intramolecular rearrangements where the total number of σ and π bonds remain unchanged.
Sigmatropic shifts are classified based on an order term [i, j ], where i and j indicate the number of atoms across which each end of the σ bond migrates. Below are examples of a [3,3] sigmatropic shift in...
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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.
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