设计,合成和研究主链聚 ((n-异环碳素) 复合物:在电色器件中的应用
Adam B Powell1, Christopher W Bielawski, Alan H Cowley
1Department of Chemistry and Biochemistry and Center for Nano and Molecular Science and Technology, The University of Texas at Austin, 1 University Station, A5300, Austin, Texas 78712-0165, USA.
Journal of the American Chemical Society
|July 9, 2010
概括
合成了新的聚 (N-异环碳) 复合物,并显示可逆的电色现象. 含有的聚合物表现出显著的近红外吸收性,作为电子沉降器.
科学领域:
- 材料科学 材料科学 材料科学
- 电化学 电化学 电化学
- 聚合物化学 聚合物化学
背景情况:
- 多N-异环碳 (NHCs) 是协调化学中的多功能联体.
- 电聚合提供了一种合成功能性聚合物材料的途径.
研究的目的:
- 合成新型的多 (N-异环碳素) 复合物.
- 研究它们的电化学和光学特性.
- 探索它们对电色应用的潜力.
主要方法:
- 由 bis ((bithiophene) 置换的单体的氧化电聚合.
- 使用电化学,X射线光电子光谱学,紫外线光谱学和导电性测量进行表征.
主要成果:
- 成功合成具有附属金属或主要集团实体的多 (N-异环碳素) 复合物.
- 由于大多数聚合物中波拉的形成,在700nm处观察到强烈的吸收.
- 含有的聚合物在1100 nm时显示出显著的近红外吸收能力.
- 在聚合物薄膜中展示高度可逆的电色现象.
结论:
- 合成的聚 (N-异环碳素) 复合物是有前途的电色材料.
- 金属部分,特别是,可以充当电子沉降器,影响光学特性.
- 碳基功能与聚合物链的正交连接使其具有独特的材料特性.
相关概念视频
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
01:26Thermal 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.