Beijing Key Laboratory of Energy Conversion and Storage Materials, College of Chemistry, Beijing Normal University, Beijing 100875, PR China.
Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, PR China.
Inorg Chem. 2021 Sep 6;60(17):13500-13509. doi: 10.1021/acs.inorgchem.1c01832. Epub 2021 Aug 17.
It is necessary to develop stable and fast multistimuli responsive materials due to the growing demand in our daily life. In this work, a new viologen-based Cd-complex () exhibits multiple thermochromic and photochromic behaviors through 10 states with 7 colors. For example, it responds to both Cu Kα/Mo Kα X-ray sources and UV dual light quickly with a color change from colorless to dark blue () (Cu Kα/Mo Kα X-ray sources) and cyan () (UV light), respectively. Interestingly, it exhibits a three-step coloration phenomenon when heated, which is unprecedented in viologen compounds. Crystal undergoes a color change to pink, blue, and brown under 130, 180, and 240 °C, respectively. In addition, upon fumigation, both and undergo a decoloration process to colorless () and yellow (), respectively. Four more states (, , , and ) obtained via dehydration-hydration treatment are all photochromic. More importantly, via single-crystal-single-crystal transformation (SC-SC), the photochromic and thermochromic behaviors of were investigated from the molecular level, which is also rather rare for thermochromic species. The detailed electron donor and the pathways for electron transfer were clearly given according to the results of crystal structure. The colorful states upon external stimuli may be attributed to the multiple pathways for electron transfer.
由于日常生活中需求的不断增长，开发稳定且快速的多重刺激响应材料是必要的。在这项工作中，一种新的基于紫罗碱的 Cd 配合物 () 通过 10 个状态和 7 种颜色表现出多种热致变色和光致变色行为。例如，它可以分别对 Cu Kα/Mo Kα X 射线源和紫外双光快速响应，颜色从无色变为深蓝色 ()（Cu Kα/Mo Kα X 射线源）和蓝绿色 ()（紫外光）。有趣的是，它在加热时表现出三步显色现象，这在紫罗碱化合物中是前所未有的。晶体在 130、180 和 240°C 下分别变为粉红色、蓝色和棕色。此外，在熏气时，和都经历褪色过程，分别变为无色 () 和黄色 ()。通过脱水-水合处理获得的另外四个状态（、、和）都是光致变色的。更重要的是，通过单晶-单晶转变（SC-SC），从分子水平研究了的光致变色和热致变色行为，这对于热致变色物质也很少见。外部刺激下的多彩状态可能归因于电子转移的多种途径。
