Design and Synthesis of Piezochromic Materials Based on Push-Pull Chromophores: A Mechanistic Perspective
Design and Synthesis of Piezochromic Materials Based on Push-Pull Chromophores: A Mechanistic Perspective
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基于推拉发色团的压致变色材料的设计与合成：机理视角
DOI：
10.1002/chem.201102929
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发表时间：
2012-04-01
影响因子：
4.3
通讯作者：
Wan, Xinhua
中科院分区：
文献类型：
--
作者：
Chen, Fengkun;Zhang, Jie;Wan, Xinhua
计算分析表明，6-位具有给电子取代基的蒽醌酰亚胺（AQI）衍生物，如4-甲基苯基、4-N，N-二甲氨基苯基和噻吩，存在分子内电荷转移（ICT）.然而，对于那些吸电子的，没有明显的ICT相互作用可以观察到。我们预测，模拟结果的基础上，AQI衍生物与供电子取代基将压致变色。为了验证这一假设，合成了相应的具有不同取代基的AQI衍生物。用漫反射法记录的粉末吸收光谱表明，4-甲基苯基、4-N，N-二甲氨基苯基和噻吩取代的AQI具有压色性，而4-硝基苯基取代的AQI没有，这与模拟结果吻合较好。有趣的是，随着发射光谱的红移，观察到较低和较高能量的吸收带的红移沿着。然而，在被压制之前和之后的XRD图案没有呈现出显著的变化，这与文献中描述的已知压致变色分子不同。一个前所未有的机制，其中增强ICT从更好的共轭之间的捐助者和受体节段诱导的减少？在压力下可能是负责的芳基取代的AQI的压色性提出。
Computational analysis predicts that intramolecular charge transfer (ICT) exists in anthraquinone imide (AQI) derivatives with electron-donating substituents at the 6-position, such as 4-methoxylphenyl, 4-N,N-dimethylaminophenyl, and thiophene. However, for those with electron-withdrawing ones, no clear ICT interaction could be observed. We predicted, on the basis of the simulation results, that AQI derivatives with electron-donating substituents would be piezochromic. To verify this hypothesis, the corresponding AQI derivatives with various substituents were synthesized. Absorption spectra recorded with a diffuse reflectance method on powders revealed that 4-methoxylphenyl-, 4-N,N-dimethylaminophenyl-, and thiophene-substituted AQI exhibited piezochromism, but not 4-nitrophenyl-substituted AQI, which is in good agreement with the simulation results. Interestingly, redshifts of both the lower and higher energy absorption bands were observed along with redshifts of the emission spectra. However, XRD patterns before and after being pressed presented no significant changes, which was different from known piezochromic molecules described in the literature. An unprecedented mechanism in which enhanced ICT from better conjugation between the donor and acceptor segments induced by the decrease of ? under pressure could be responsible for the piezochromism of aryl-substituted AQIs is proposed.