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 Δλ=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.

中文翻译：

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一系列7-二乙基氨基香豆素酰胺化合物的高效溶液和固态荧光

合成了一系列带有苯基（1），苄基（2）和苯并噻唑（3）端基的7-二乙基氨基香豆素酰胺化合物。化合物1和2的晶体结构是通过单晶X射线衍射确定的。所有这些化合物在两种THF表现出强烈的蓝色荧光和高荧光量子产率（1：0.36，2：0.43，3：0.27）和高粘度溶剂（甘油; 1：0.32，2：0.38，3：0.41）。化合物1显示亮黄绿色荧光，最大荧光强度为λ = 537 nm，固态（粉末）状态的量子产率为0.47。对于化合物1，我们观察到Δλ = 72 nm的红移和相对于THF的固态荧光增强。化合物2在固态下发出亮蓝色荧光（λ = 463 nm，Φ = 0.36），相对于THF（λ = 466 nm vsλ = 482 nm）略有蓝移，并显示为窄峰半峰全宽仅为39 nm。高粘度甘油溶液和固态中强烈的荧光发射可能归因于7-二乙氨基的旋转受限，这导致了非辐射失活。