RESUMO
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 × 105-1.05 × 105 M-1.cm-1) 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-1. 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.
RESUMO
A new chemodosimeter for fluoride ions based on F(-) triggered dual Si-O bond cleavage of distyrylbenzenes derivatives was developed for the first time. Upon the addition of F(-) ions, the chemodosimeter (7) displayed apparent color changes from colorless to faint yellow, with a dramatic red-shift in the emission wavelength (~100 nm), and higher selectivity for fluoride over other common anions. With the aid of fluorescence measurements, the limit of detection could be as low as 89.8 nm. Using a 'dipstick' approach, chemodosimeter (7) might serve as a prototype device for fluorescent detecting F(-) without the need for any additional equipment. Copyright © 2015 John Wiley & Sons, Ltd.