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Updated: Apr 29, 2026

Synthesis of Programmable Main-chain Liquid-crystalline Elastomers Using a Two-stage Thiol-acrylate Reaction
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Synthesis of Programmable Main-chain Liquid-crystalline Elastomers Using a Two-stage Thiol-acrylate Reaction

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加熱/冷却の刺激は,偽エナチオメリックアミノメチレンヘリセンのオリゴーマー3つの状態の分子スイッチングを誘導します:可逆的な非均衡の熱力学プロセス

Masanori Shigeno1, Yo Kushida, Masahiko Yamaguchi

  • 1Department of Organic Chemistry, Graduate School of Pharmaceutical Sciences, Tohoku University , Aoba, Sendai 980-8578, Japan.

Journal of the American Chemical Society
|May 14, 2014
PubMed
まとめ

擬似抗酸化ヘリケンは,温度によって相互変換する3つの異なる状態 (A,B,C) を表し,ヒステリシスや凍結のような複雑な熱力学的行動を示す. これらの分子は,非均衡系を理解するために不可欠な,可逆的な構造的なスイッチングを示します.

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Determination of the Photoisomerization Quantum Yield of a Hydrazone Photoswitch09:33

Determination of the Photoisomerization Quantum Yield of a Hydrazone Photoswitch

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High-Contrast and Fast Photorheological Switching of a Twist-Bend Nematic Liquid Crystal06:24

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関連する概念動画

[3,3] Sigmatropic Rearrangement of 1,5-Dienes: Cope Rearrangement01:21

[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.
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Thermal Sigmatropic Reactions: Overview01:16

Thermal Sigmatropic Reactions: Overview

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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Thermal 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.
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Regioselectivity and Stereochemistry of Acid-Catalyzed Hydration02:34

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The rate of acid-catalyzed hydration of alkenes depends on the alkene's structure, as the presence of alkyl substituents at the double bond can significantly influence the rate.
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Cycloaddition Reactions: MO Requirements for Photochemical Activation01:12

Cycloaddition 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.
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Cycloaddition Reactions: MO Requirements for Thermal Activation01:16

Cycloaddition Reactions: MO Requirements for Thermal Activation

Thermal cycloadditions are reactions where the source of activation energy needed to initiate the reaction is provided in the form of heat. A typical example of a thermally-allowed cycloaddition is the Diels–Alder reaction, which is a [4 + 2] cycloaddition. In contrast, a [2 + 2] cycloaddition is thermally forbidden.
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