A Smart Cyclic Azobenzene as Pendant Groups on Polymer Chains: Topological Effect of the Cyclization on Thermal and Photoresponsive Properties of the Azobenzene and the Polymer
A Smart Cyclic Azobenzene as Pendant Groups on Polymer Chains: Topological Effect of the Cyclization on Thermal and Photoresponsive Properties of the Azobenzene and the Polymer
复制标题
智能环状偶氮苯作为聚合物链上的侧基：环化对偶氮苯和聚合物的热响应和光响应性能的拓扑效应
DOI：
10.1002/asia.201300154
复制
发表时间：
2013
影响因子：
4.1
通讯作者：
Zhu Xiulin
中科院分区：
文献类型：
--
作者：
Li Jiangyu;Zhou Nianchen;Zhang Zhengbiao;Xu Ying;Chen Xinrong;Tu Yingfeng;Hu Zhijun;Zhu Xiulin
在过去的二十年中，偶氮苯化合物已经发展成为最强大的一类光致变色材料，这归功于许多重要的发现和应用，例如光学数据存储，[1]液晶显示器，[2]光学开关，[3]和光致表面浮雕光栅（SRG）。偶氮苯的E和Z形式之间的可逆转化可以通过用UV光照射来诱导，并且在加热或用可见光照射时逆转。通常，偶氮苯的Z异构体比E异构体更不稳定。然而，当偶氮苯发色团被置于构象应变下时，Z异构体可以被“锁定”。例如，Z异构体可以通过将偶氮苯掺入环状分子体系中来稳定。[5a]Tamaoki及其同事合成了环状偶氮苯二聚体，并表明环应变增加了偶氮苯部分的热Z至E异构化的活化能和活化熵。[5b偶氮苯的光异构化导致其分子构象和偶极矩的大的变化。其结果是，偶氮苯轴承化合物的功能性显着改变。[6]因此，将偶氮苯部分掺入大环支架中为开发具有不同功能的分子器件提供了许多机会。李和同事重新-
Over the past two decades, azobenzene compounds have developed to become one of the most powerful classes of photochromic materials, owing to a number of important discoveries and applications, such as optical-data storage,[1] liquid-crystal displays,[2] optical switching,[3] and photoinduced surface-relief gratings (SRGs),[4] that have been made in this field.The reversible transformation between the E and Z forms of an azobenzene can be induced by irradiation with UV light and reversed upon heating or irradiation with visible light. Typically, the Z isomer of an azobenzene is less stable than the E isomer. However, the Z isomers can be “locked” when azobenzene chromophores are placed under conformational strain. For example, the Z isomers can be stabilized by incorporating azobenzene into cyclic molecular systems.[5a] Tamaoki and co-workers synthesized a cyclic azobenzene dimer and showed that the ring strain increased the activation energy and activation entropy for the thermal Z-to-E isomerization of the azobenzene moiety.[5b, c] The photoisomerization of an azobenzene causes large changes in its molecular conformation and dipole moment. As a result, the functionality of azobenzene-bearing compounds is observably changed.[6] Therefore, the incorporation of azobenzene moieties into macrocyclic scaffolds offers many opportunities for the development of molecular devices with diverse functionalities. Li and co-workers re-