The superiority of nonconjugated structures in fluorescence:through-space vs.through-bond charge transfer  

作　　者：Weihao Tu Zuping Xiong Lei Wang Jianyu Zhang Jing Zhi Sun Haoke Zhang Ben Zhong Tang 

机构地区：[1]MOE Key Laboratory of Macromolecular Synthesis and Functionalization,Department of Polymer Science and Engineering,Zhejiang University,Hangzhou 310058,China [2]Zhejiang-Israel Joint Laboratory of Self-Assembling Functional Materials,ZJU-Hangzhou Global Scientific and Technological Innovation Center,Zhejiang University,Hangzhou 311215,China [3]Centre of Healthcare Materials,Shaoxing Institute,Zhejiang University,Shaoxing 312000,China [4]Department of Chemistry,Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration and Reconstruction,The Hong Kong University of Science and Technology,Hong Kong 999077,China [5]School of Science and Engineering,Shenzhen Institute of Aggregate Science and Technology,The Chinese University of Hong Kong,Shenzhen(CUHK-Shenzhen),Guangzhou 518172,China

出　　处：《Science China Chemistry》2024年第9期3121-3130,共10页中国科学（化学英文版）

基　　金：supported by the National Natural Science Foundation of China(22205197);the project funded by China Postdoctoral Science Foundation(2022M712721)。

摘　　要：Constructing charge transfer(CT)state by introducing donor(D)and acceptor(A)is an efficient strategy to regulate the photophysical properties of luminescent materials.Traditional CT-type luminophores are built onπ-conjugated fused-ring structures,which always show hybrid CT/locally excited(LE)states and luminescence quenching effect in the aggregate state.In this work,eight conjugated biphenyl(BP)and nonconjugated diphenylmethane(DPM)derivatives with different donors and acceptors are synthesized to investigate the CT properties.Systematic photophysical characterization and theoretical calculation demonstrate that the through-space CT(TSCT)in nonconjugated DA-DPM exhibit superior photophysical performance than the conjugated DA-BP with through-bond CT(TBCT),the main manifestations are as follows:(1)TSCT luminophores produce longer maximum emission wavelength(λ_(em))than the corresponding TBCT ones.For example,the longest λ_(em)of DMA-CN-DPM(DMA,dimethylamino)is 621 nm but the corresponding λ_(em)of DMA-CN-BP is only 480 nm.(2)TSCT-based DA-DPM demonstrates more sensitive responsiveness to environmental stimuli such as temperature and polarity.(3)Complete separation of the the highest occupied molecular orbital(HOMO)and the lowest unoccupied molecular orbital(LUMO)distribution exists in all kinds of conformation of DA-DPM,which was hard to realize in conjugated DA-BP.

关 键 词：through-space charge transfer through-space conjugation clusteroluminescence DIPHENYLMETHANE 

分 类 号：TB34[一般工业技术—材料科学与工程] O641.3[理学—物理化学]