内分子基芳香化:扩展 [9] 和π-扩展双 [4] 的意想不到的合成,以及它们在晶体管内存上的分子几何效应
Yang Yu1, Le Wang2, Chang Wang1
1Department of Chemistry and State Key Laboratory of Synthetic Chemistry The University of Hong Kong Hong Kong 999077 China.
Small science
|April 11, 2025
概括
这项研究引入了一种新方法来合成非平面的多环芳,产生两个异构体. 这些异构体显示了有机场效应晶体管非挥发性内存设备的独特特性,突出了几何形状.
科学领域:
- 有机化学 有机化学
- 材料科学 材料科学 材料科学
- 纳米技术纳米技术
背景情况:
- 内分子基芳香化是合成复杂的多环芳的关键.
- 非平面分子纳米碳素对于先进的电子应用至关重要.
研究的目的:
- 描述一个意想不到的三酸促进的分子内基醇芳香化.
- 合成和描述两个结构异构体:扩展 [9] 烯和π-扩展双 [4] 烯.
- 研究分子几何学对光电子特性和设备性能的影响.
主要方法:
- 三酸促进的循环化反应.
- 单晶X射线衍射用于结构分析.
- 紫外线吸收,光发光谱学和循环电压测量用于属性评估.
- 有机场效应晶体管非挥发性存储器 (OFET-NVM) 设备的制造和测试.
主要成果:
- 两种异构体,扩展 [9] (1) 和 π 扩展双 [4] (2),已成功合成.
- 这两种异构体都表现出很大的能量差距和类似的能量水平,适合OFET-NVMs.
- 非平面几何学显著影响电荷捕获行为,同位素1显示更宽的内存窗口 (44.5V) 比同位素2 (14.2V).
- 实现了1.08 × 1013 cm-2 的高电荷捕获密度.
结论:
- 分子几何控制是优化有机电子中的分子纳米碳化合物的新策略.
- 来自不同几何形状的独特分子包装模式导致了不同的电荷捕获行为.
- 这项工作为先进的存储器设备提供了一个新的合成路线和对结构属性关系的洞察.
相关概念视频
02:38Electrophilic Addition to Alkynes: Halogenation
8.1K
Introduction
Halogenation is another class of electrophilic addition reactions where a halogen molecule gets added across a π bond. In alkynes, the presence of two π bonds allows for the addition of two equivalents of halogens (bromine or chlorine). The addition of the first halogen molecule forms a trans-dihaloalkene as the major product and the cis isomer as the minor product. Subsequent addition of the second equivalent yields the tetrahalide.
Halogenation is another class of electrophilic addition reactions where a halogen molecule gets added across a π bond. In alkynes, the presence of two π bonds allows for the addition of two equivalents of halogens (bromine or chlorine). The addition of the first halogen molecule forms a trans-dihaloalkene as the major product and the cis isomer as the minor product. Subsequent addition of the second equivalent yields the tetrahalide.
8.1K
01:26Thermal and Photochemical Electrocyclic Reactions: Overview
2.3K
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.
2.3K
02:46Halogenation of Alkenes
15.1K
Halogenation is the addition of chlorine or bromine across the double bond in an alkene to yield a vicinal dihalide. The reaction occurs in the presence of inert and non-nucleophilic solvents, such as methylene chloride, chloroform, or carbon tetrachloride.
Consider the bromination of cyclopentene. Molecular bromine is polarized in the proximity of the π electrons of cyclopentene. An electrophilic bromine atom adds across the double bond, forming a cyclic bromonium ion intermediate.
Consider the bromination of cyclopentene. Molecular bromine is polarized in the proximity of the π electrons of cyclopentene. An electrophilic bromine atom adds across the double bond, forming a cyclic bromonium ion intermediate.
15.1K
01:17Electrophilic 1,2- and 1,4-Addition of HX to 1,3-Butadiene
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The electrophilic addition of hydrogen halides such as HBr to alkenes and nonconjugated dienes gives a single product as per Markovnikov’s rule.
5.1K
02:27Preparation of Alkynes: Alkylation Reaction
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Introduction
Alkylation of terminal alkynes with primary alkyl halides in the presence of a strong base like sodium amide is one of the common methods for the synthesis of longer carbon-chain alkynes. For example, treatment of 1-propyne with sodium amide followed by reaction with ethyl bromide yields 2-pentyne.
Alkylation of terminal alkynes with primary alkyl halides in the presence of a strong base like sodium amide is one of the common methods for the synthesis of longer carbon-chain alkynes. For example, treatment of 1-propyne with sodium amide followed by reaction with ethyl bromide yields 2-pentyne.
9.7K
01:17Thermal Electrocyclic Reactions: Stereochemistry
1.9K
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.
1.9K