摘要
A series of vibratile π-extended dihydrophenazines(BPs)and a tetrahydrodiphenazine(TP)were synthesized via direct C-N coupling reactions.Structural alterations of the fused acene wings lead to diverse intermolecular packing arrangements as well as tunable photophysical properties.These compounds exhibit intriguing features,including large Stokes shift,multiple emissions,and environmental effects.Notably,a dramatic hypsochromic shift in emission is observed when the acene wing is linearly extended from benzene to naphthalene and anthracene.This unusual π-conjugation length-dependent emission is explained by the close correlation between the calculated fluorescence-emitting energy and the π-conjugation length of the acene subunit.In addition,the TP bearing two flexible units exhibits dynamic photophysical properties resembling those of BPs.Our results reveal a balanced control over π-conjugation and luminescence in vibratile π-systems,thereby providing new insight into the molecular design of organic near-infrared fluorophores with large Stokes shifts and dynamic emissions.
基金
financially supported by the National Natural Science Foundation of China(NSFC)(grant nos.21788102,22025503,21790361,and 21871084)
Shanghai Municipal Science and Technology Major Project(grant no.2018SHZDZX03)
the Fundamental Research Funds for the Central Universities
the Programme of Introducing Talents of Discipline to Universities(grant no.B16017)
Program of Shanghai Academic/Technology Research Leader(grant no.19XD1421100)
the Shanghai Science and Technology Committee(grant no.17520750100)
the China Postdoctoral Science Foundation(grant no.2020M671018).
