Photo Switchable Two-step Photochromism in a Series of Ln-Phosphonate(Ln=Dy,Gd,Tb,Y)Dinuclear Complexes  

作　　者：HU Ji-Xiang ZHANG Qian XIA Bin LIU Tao PANG Jiandong BU Xian-He 

机构地区：[1]School of Materials Science and Engineering,Nankai University,Tianjin 300350,P.R.China [2]College of Chemistry and Chemical Engineering,Qingdao University,Shandong 266071,P.R.China [3]State Key Laboratory of Fine Chemicals,Dalian University of Technology,Dalian 116024,P.R.China

出　　处：《Chemical Research in Chinese Universities》2022年第1期58-66,共9页高等学校化学研究（英文版）

基　　金：This work was supported by the National Natural Science Foundation of China(Nos.21901133,91856124,22035003,91961114,21871039);China National Postdoctoral Program for Innovative Talents(No.BX20180147).

摘　　要：Exploring the discrete complexes with multi-step coloration is still a challenge in the field of electron transfer photochromic materials. Herein, we synthesized a series of dinuclear Ln-diphosphonate compounds[Ln=Dy(1);Gd(2);Tb(3);Y(4)] with a remarkably and reversibly photoactive coloration phenomenon. These compounds showed two-step coloration behavior, which were the first discrete architectures in the reported electron transfer photochromic complexes. This two-step coloration phenomenon was originated from the large distortion of H3-TPT acceptors, which in turn reduced the π-conjugation of electron acceptors and slowed the decay process of electron transfer. The photogenerated stable doublet radicals originated from electron transfer from diphosphonate donor to polypyridine acceptor in these complexes were detected by UV-Vis and electron spin resonance(ESR) spectra. Furthermore, the photogenerated radicals were estimated by direct current magnetic susceptibilities and variable temperature ESR spectra, suggesting the doublet radicals in the dinuclear structure for all the compounds. This work revealed a series of discrete phosphonate-based systems with a multi-step coloration process, providing a new pathway for designing multicolor photochromic materials with potential photoswitching or other applications.

关 键 词：Discrete structure Donor-acceptor system Doublet radical PHOTOMAGNETISM Two-step photochromism 

分 类 号：O62[理学—有机化学]