Reversible Photochromic Coordination Polymer by Phototriggered Subtle Molecular Conformation Variations
Reversible Photochromic Coordination Polymer by Phototriggered Subtle Molecular Conformation Variations
复制标题
光触发细微分子构象变化可逆光致变色配位聚合物
DOI：
10.1021/acs.inorgchem.1c02657
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发表时间：
2021-12-20
影响因子：
4.6
通讯作者：
Cao, Qiu-E
中科院分区：
文献类型：
--
作者：
Wang, Qiu-Feng;Fan, Hong-Chuan;Cao, Qiu-E
光致变色材料是由分子在光的作用下发生结构变化而构成的，具有重要的应用价值。然而，由于空间限制效应，这些光响应生色团在配位聚合物（CPs）中的分子堆积会导致效率降低和响应延迟，从而导致光致变色性能变差。由（Z）-1，2-二苯基-1，2-双[4-（吡啶-3-基甲氧基）苯基]乙烯（1 Z）和CuI原子簇合成的具有三重互穿网络结构的CP（CIT-E）显示出快速可逆的光致变色行为。在紫外光照射下，CIT-Z的颜色由浅黄色变为红棕色。在绿色光照射下，聚合物在10 s内即可恢复到初始颜色。为了揭示CIT-Z可逆光致变色行为的机理，本文对CIT-Z各色态的单晶结构进行了全面的研究，并采用含时密度泛函理论计算和控制实验等科学研究方法。结果表明，CIT-Z在光照条件下的这种行为是配体-金属电荷转移过程的结果，而这一过程是由四苯乙烯分子构象的细微变化触发的.值得注意的是，CIT-Z具有高的热稳定性和化学稳定性，这是作为智能光响应材料的优异优势。作为概念的证明，具有这种迷人的光致变色特性的均匀薄膜可以应用于隐形防伪和动态光学数据存储。总的来说，本研究开辟了一个新的途径，可逆的光致变色材料。
Photochromic materials are constructed with molecules accompanied by structural change after triggering by light, which are of great importance and necessity for various applications. However, because of space-confinement effects, molecule stacking of these photoresponsive chromophores within coordination polymers (CPs) always results in an efficiency decrement and a response delay, and this phenomenon will lead to a poor photochromic property. Herein, a CP (named CIT-E) with a 3-fold-interpenetrating network structure, which was prepared with (Z)-1,2-diphenyl-1,2-bis[4-(pyridin-3-ylmethoxy)phenyl] ethene (1Z) and a CuI cluster, showed fast reversible photochromic behavior. Under UV-light illumination, the color of CIT-Z changed from pale yellow to reddish brown. With the illumination of green light, the polymer could return to its initial color within 10 s. To reveal the mechanism of reversible photochromic behavior of CIT-Z, single-crystal structures of each color state were fully studied, and other scientific study methods were also used, such as time-dependent density functional theory calculation and control experiments. It was found that, with light illumination, this behavior of CIT-Z was the result of a ligand-to-metal charge-transfer process, and this process was triggered by subtle molecular conformation variation of tetraphenylethylene. It should be noted that CIT-Z has high thermal and chemical stability, which are excellent advantages as smart photoresponsive materials. As a proof of concept, a uniform thin film with such a fascinating photochromic property allows applications in invisible anticounterfeiting and dynamic optical data storage. Overall, the present study opens up a new avenue toward reversible photochromic materials.