Push–pull type fluorophores are often exploited as a biological probe because of their high environment-sensitivity nature. Herein, we report the potentiality of a push–pull fluorophore, 2-formyl-5-(4′-N,N-dimethylaminophenyl)thiophene, as a membrane probe. This molecule exhibits strong absorbance in the violet region (∼400 nm) and a high emission quantum yield (≤0.6). The emission is highly sensitive to the surrounding environment, and a high Stokes shift (>7000 cm^–1) appears in strong polar solvents. The molecule is highly susceptible to the fluorescence quenching by protic solvents. The neutral probe efficiently senses aprotic environments such as lipid bilayer membranes through all six fluorescence parameters: emission maxima, intensity, and anisotropy as well as the corresponding time-dependent parameters. The small and flat shape, nonemissive nature in the aqueous medium along with the high susceptibility to all six fluorescence parameters of the molecule strongly suggests a promising fluorescence probe for biological medium.

中文翻译：

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高度环境敏感的荧光团对膜双层性能的多参数传感

推挽型荧光团由于其对环境的高度敏感性而经常被用作生物探针。在此，我们报道了推挽式荧光团2-甲酰基-5-（4'- N，N-二甲基氨基苯基）噻吩作为膜探针的潜力。该分子在紫色区域（〜400 nm）具有很强的吸收能力，并具有很高的发射量子产率（≤0.6）。辐射对周围环境高度敏感，斯托克斯位移高（> 7000 cm ^–1）出现在强极性溶剂中。该分子对质子溶剂的荧光猝灭非常敏感。中性探针通过所有六个荧光参数（发射最大值，强度和各向异性以及相应的随时间变化的参数）有效地感应非质子环境，例如脂质双层膜。水性介质的小而扁平的形状，无辐射的性质以及对分子的所有六个荧光参数的高度敏感性，强烈表明了一种有前途的生物介质荧光探针。