Wei Wu-Ji, Mu Ying, Wei Li, Hu Ji-Xiang, Wang Guo-Ming
College of Chemistry and Chemical Engineering, Qingdao University, Qingdao, Shandong 266071, People's Republic of China.
Inorg Chem. 2021 Jan 4;60(1):108-114. doi: 10.1021/acs.inorgchem.0c02463. Epub 2020 Dec 22.
Stimulating tunable room-temperature phosphorescence (RTP) is still a challenge in photochromic systems, which is vital for multifunctional coordination materials. Herein, we synthesized two new photochromic chain complexes through self-assembly of the nonphotochromic 1,3,5-tris(4-pyridyl)benzene ligand, diphosphonate, and Ln(III) ions ( for Ln(III) = Dy and for Ln(III) = Gd). Both compounds showed fast photoresponses with the color turning from yellow to dark gray with a reversible decoloration by heating or storage in the dark. The electron transfer photochromic behavior with the generated stable radicals was further confirmed by the room-temperature UV-vis and electron paramagnetic resonance spectra. Furthermore, via tuning the generation and disappearance of stable radicals, reversible room-temperature fluorescence and phosphorescence for both compounds were switched by light irradiation and a thermal treatment, with an enhanced intensity for RTP and a decrease in fluorescence during the duration of Xe-lamp light irradiation. This work provides a new strategy that photogenerated radicals could promote and enhance RTP properties in functional materials.
在光致变色体系中激发可调室温磷光（RTP）仍然是一项挑战，而这对于多功能配位材料至关重要。在此，我们通过非光致变色的1,3,5-三（4-吡啶基）苯配体、二膦酸盐和Ln(III)离子（Ln(III) = Dy以及Ln(III) = Gd）的自组装合成了两种新型光致变色链状配合物。两种化合物均表现出快速的光响应，颜色从黄色变为深灰色，通过加热或在黑暗中储存可实现可逆褪色。室温紫外可见光谱和电子顺磁共振光谱进一步证实了产生稳定自由基的电子转移光致变色行为。此外，通过调节稳定自由基的产生和消失，两种化合物的可逆室温荧光和磷光可通过光照射和热处理进行切换，在氙灯光照射期间RTP强度增强而荧光减弱。这项工作提供了一种新策略，即光生自由基可以促进和增强功能材料中的RTP性质。
