Tetraphenylethylene-derived organic cages with persistent photogenic radicaloids and efficient photothermal conversion  

作　　者：Suqiong Yan Bo Yang Fanda Feng Yuan Zhang Shirong Ban Hui Ma Wei Huang 

机构地区：[1]State Key Laboratory of Coordination Chemistry,School of Chemistry and Chemical Engineering,Nanjing University,Nanjing 210093,China [2]Shenzhen Research Institute of Nanjing University,Shenzhen 518057,China

出　　处：《Science China Chemistry》2025年第2期661-669,共9页中国科学(化学英文版)

基　　金：Foundation of China(21871133);the Natural Science Foundation of Jiangsu Province(BK20211146);the Science,Technology,and Innovation Commission of Shenzhen Municipality(JCYJ20180307153251975)for financial support。

摘　　要：Transformation of the electronic spin states has received significant interest in recent years because of its applications in the magnetic information storage materials and optical response switches.However,it can be formidably challenging to use ultraviolet(UV)light as a contactless stimulus to alter the electronic spin states of the supramolecular cages.Inspired by the approach on the radical cation mechanism of the Scholl reaction and the photocyclization reactivity of tetraphenylethylene(TPE)derivatives,we report two photochromic cages(cage-TPE-1 and cage-TPE-2)that can be photochemically transformed from electron paramagnetic resonance(EPR)-silent to EPR-active form via UV irradiation due to the photo-induced electron transfer process at the TPE moiety.EPR provided a strong single-electron signal with a g value of 2.003 in cage-TPE-1 and cage-TPE-2 but no signal was detected for the pristine samples without the UVexposure.The transformation can be monitored by ultraviolet–visible–near-infrared(UV–vis–NIR)and photoluminescence(PL)spectroscopy.The photogenic radical cage intermediate was unstable in solution resulting in the degradation and intramolecular cyclization of the reactive species,while the radicals were found to be stable and persistent in the solid state due to the spin delocalization,the steric protection of confined cavities,and the oxygen isolation.Both theoretical calculations and spectral measurements suggest that the photogenic radical cage-TPE-2(•+)experiences photocyclization on the TPE core.Compared with the close-shell cage,the radical cage-TPE-1(•+)and cage-TPE-2(•+)exhibit better photothermal conversion performance due to the incubated infrared absorption from open-shell electron feature and reduced band gap.

关 键 词：supramolecular cage photogenic radical PHOTOCYCLIZATION photothermal conversion 

分 类 号：O641.3[理学—物理化学]