定义导电聚合物周围的空间:可逆性质子兴奋剂对一个覆盖的多聚烯进行反转
Dongwhan Lee1, Timothy M Swager
1Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, Massachusetts 02139, USA.
Journal of the American Chemical Society
|June 5, 2003
概括
一种新型的醇衍生物被合成和聚合,以创建一种高度导电的聚合物. 它的导电性可以通过去质子化和重质子化精确调节,因此非常适合传感应用.
科学领域:
- 材料科学 材料科学 材料科学
- 聚合物化学 聚合物化学
- 有机电子 有机电子
背景情况:
- 尽量减少链间pi-pi堆叠对于开发导电聚合物至关重要.
- 醇衍生物是功能性聚合物的多功能构件.
研究的目的:
- 为了合成一个设计用于限制pi-pi堆叠的树冠形状的醇衍生物.
- 为了研究由此产生的聚合物的导电性和电子结构.
- 探索这种聚合物在基于电阻的传感中的潜力.
主要方法:
- 一个硬质阻碍的醇衍生物的阳极聚合.
- 光谱电化学技术用于探测电子结构.
- 通过deprotonation/reprotonation进行导电性调制的研究.
主要成果:
- 成功合成了一种树冠形状的醇衍生物 (2).
- 阳极聚合产生了一种高度导电的聚合物 (聚二).
- 观察到有限的电荷移位,导致了明确的导电性概况.
- 导电性通过可逆去质子化和再质子化精确调节.
结论:
- 设计的醇衍生物有效地减少了链间pi-pi堆叠.
- 聚二具有高导电性和适合传感的可调性特性.
- 可逆去质子化/反质子化为聚合物中的导电性控制提供了一种新的方法.
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.
01:17Thermal 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.
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
01:17Pericyclic Reactions: Introduction
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 rearrangements are...
Pericyclic reactions can be classified into three categories: electrocyclic reactions, cycloaddition reactions, and sigmatropic rearrangements. Electrocyclic reactions and sigmatropic rearrangements are...
01:17Ion Exchange
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01:24Types of Reversible Electrodes
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