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Efficient Solution‐ and Solid‐State Fluorescence for a Series of 7‐Diethylaminocoumarin Amide Compounds
Author(s) -
Sun Yatong,
Sun Yunhui,
Zhao Songfang,
Cao Duxia,
Guan Ruifang,
Liu Zhiqiang,
Yu Xueying,
Zhao Xun
Publication year - 2018
Publication title -
asian journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.846
H-Index - 44
eISSN - 2193-5815
pISSN - 2193-5807
DOI - 10.1002/ajoc.201700555
Subject(s) - chemistry , fluorescence , quantum yield , benzothiazole , amide , photochemistry , solvent , crystallography , analytical chemistry (journal) , organic chemistry , optics , physics
A series of 7‐diethylaminocoumarin amide compounds with phenyl ( 1 ), benzyl ( 2 ), and benzothiazole ( 3 ) terminal groups have been synthesized. The crystal structures of compounds 1 and 2 were determined by using single‐crystal X‐ray diffraction. All of these compounds exhibited intense blue fluorescence and high fluorescence quantum yields in both THF ( 1 : 0.36, 2 : 0.43, 3 : 0.27) and high‐viscosity solvent (glycerol; 1 : 0.32, 2 : 0.38, 3 : 0.41). Compound 1 displayed bright‐yellow–green fluorescence, with a fluorescence maximum at λ =537 nm and a quantum yield of 0.47 in the solid (powder) state. For compound 1 , we observed a red shift of Δ λ =72 nm and fluorescence enhancement in the solid state relative to that in THF. Compound 2 emitted bright‐blue fluorescence ( λ =463 nm, Φ =0.36) in the solid state, which was slightly blue‐shifted relative to that in THF ( λ =466 nm vs λ =482 nm) and appeared as a narrow peak with a full‐width‐at‐half‐maximum of only 39 nm. The strong fluorescence emission in high‐viscosity glycerol solution and in the solid state may be attributed to restriction of the rotation of the 7‐diethylamino group, which led to non‐radiative deactivation.