Miri Fateme Sadat, Gorji Kandi Saeideh, Panahi Farhad
Department of Polymer Engineering and Color Technology, Amirkabir University of Technology, Tehran, Iran.
Department of Chemistry, College of Sciences, Shiraz University, Shiraz, 71454, Iran.
J Fluoresc. 2020 Jul;30(4):917-926. doi: 10.1007/s10895-020-02567-2. Epub 2020 Jun 5.
In this study, a π-conjugated organic compound based on distyrylbenzenes contains an amino substituent (as an electron-donor group) and a sulfone moiety (as an electron-withdrawing group) was investigated in the viewpoint of solvatochromism effects and the possibility of pH-sensitivity. This fluorescence dye (2-(ethyl(4-((E)-4-((E)-4-(methylsulfonyl)styryl)styryl)phenyl)amino)ethan-1-ol, ASDSB) showed Uv-Vis absorption in the range of 377-407 nm with high molar extinction coefficients (ε = 0.05 × 10-1.05 × 10 M.cm) in tested solvents with different polarities. This fluorescent compound emits in the region of visible spectrum (513-631 nm) with Stokes shifts of 5077.02-8912.66 cm. The combination of ASDSB with poly(methyl methacrylate) (PMMA) and polyvinyl alcohol(PVA) polymers exhibits different photophysical properties which related to the polarity of polymers. By change of pH of dissolved ASDSB in methanol, a hypsochromic shift was observed. This phenomena is correspond to the change of chromophore upon protonation of amino group and its conversion to ammonium salt. In the case of solid samples, the bathochromic shifts (426-535 nm) were observed at the maximum emission wavelength for PMMA polymer. While no significant change in the maximum emission wavelength of ASDSB in PVA polymer were detected.
在本研究中，从溶剂化显色效应和pH敏感性的可能性角度，对一种基于二苯乙烯基苯的含有氨基取代基（作为给电子基团）和砜部分（作为吸电子基团）的π共轭有机化合物进行了研究。这种荧光染料（2-(乙基(4-((E)-4-((E)-4-(甲基磺酰基)苯乙烯基)苯乙烯基)phenyl)氨基)乙醇，ASDSB）在不同极性的测试溶剂中，紫外可见吸收范围为377 - 407 nm，具有高摩尔消光系数（ε = 0.05×10 - 1.05×10 M·cm）。这种荧光化合物在可见光谱区域（513 - 631 nm）发射，斯托克斯位移为5077.02 - 8912.66 cm。ASDSB与聚甲基丙烯酸甲酯（PMMA）和聚乙烯醇（PVA）聚合物的组合表现出与聚合物极性相关的不同光物理性质。通过改变溶解在甲醇中的ASDSB的pH值，观察到蓝移。这种现象对应于氨基质子化后发色团的变化及其向铵盐的转化。对于固体样品，在PMMA聚合物的最大发射波长处观察到红移（426 - 535 nm）。而在PVA聚合物中未检测到ASDSB的最大发射波长有显著变化。
