Synthesis and optical properties, including fluorosolvatochromic and ICT-based proton-sensing behaviors of a series of 2,4,6-tris(5-aryl-2-thienyl)pyridines
Synthesis and optical properties, including fluorosolvatochromic and ICT-based proton-sensing behaviors of a series of 2,4,6-tris(5-aryl-2-thienyl)pyridines
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DOI：
10.1080/10426507.2019.1603230
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发表时间：
2019-04
期刊：
影响因子：
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通讯作者：
H. Muraoka;T. Obara;S. Ogawa
中科院分区：
文献类型：
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作者：
H. Muraoka;T. Obara;S. Ogawa
摘要设计并合成了一系列2,4,6-三（5-芳基-2-噻吩基）吡啶星形共轭（D-π）3-A体系，该体系由一个缺电子的吡啶核(A)和三个芳基与一个供电子取代基(D)由一个噻吩间隔剂（π-间隔剂）连接而成。这些分子在溶液和固体状态下的光学性质，通过紫外-可见吸收和荧光光谱鉴定，清楚地表明紫外-可见吸收和荧光波长是由末端芳基的施主强度控制的。此外，2,4,6-三[5-（4- n， n-二丁基氨基苯基）-2-噻吩基]吡啶由于其强大的分子内电荷转移（ICT）特性表现出荧光溶剂致变色行为，并随着视觉溶液和荧光颜色的变化，根据氨基氮原子和吡啶氮原子的逐步质子化表现出质子诱导的两步光谱位移。因此，我们发现该分子可以作为一种光学传感器，能够视觉检测溶剂极性和质子。图形抽象
Abstract A series of 2,4,6-tris(5-aryl-2-thienyl)pyridines with a star-shaped π–conjugated (D-π)3-A system, which consist of an electron deficient pyridine core (A) and three aryl groups with an electron-donating substituent (D) linked by a thiophene spacer (π-spacer), were designed and systematically synthesized. The optical properties of these molecules in the solution and solid states, which were identified by UV-vis absorption and fluorescence spectroscopies, clearly indicated that the UV-vis absorption and fluorescence wavelengths are controlled by the donor strength of the terminal aryl groups. Additionally, 2,4,6-tris[5-(4-N,N-dibutylaminophenyl)-2-thienyl]pyridine exhibited a fluorosolvatochromic behavior based on its strong intramolecular charge transfer (ICT) characteristic and displayed proton-induced two-step optical spectral shifts depending on its stepwise protonation of the amino nitrogen atoms and pyridinyl nitrogen atom with stepwise visual solution and fluorescence color changes. Consequently, we revealed that the molecule serves as an optical sensor capable of the visual detection of solvent polarity and a proton. Graphical Abstract