Photophysical properties and immobilisation of fluorescent pH responsive aminated benzimidazo[1,2-a]quinoline-6-carbonitriles (CROSBI ID 270077)
Prilog u časopisu | izvorni znanstveni rad | međunarodna recenzija
Podaci o odgovornosti
Horak, Ema ; Babić, Darko ; Vianello, Robert ; Perin, Nataša ; Hranjec, Marijana ; Murković Steinberg, Ivana
engleski
Photophysical properties and immobilisation of fluorescent pH responsive aminated benzimidazo[1,2-a]quinoline-6-carbonitriles
This work presents a systematic evaluation of 2-amino, 5-amino and 2, 5-diamino substituted benzimidazo[1, 2 a]quinoline-6-carbonitriles as novel pH probes with a potential application in pH sensing materials or as H+ fluoroionophores in bulk optode membranes. The study was carried out by varying the length, type and position of amino substituents in ten fluorescent dyes with the same benzimidazo[1, 2-a]quinoline-6- carbonitrile core. The photophysical and acid- base properties of the dyes were investigated by the UV/Vis absorption and fluorescence spectroscopies, and interpreted by the electronic structure DFT calculations. pH sensing mechanisms and structure-property relations affecting the fluorescence response were discussed through a detailed analysis of the piperidine substituted derivatives 1–4. Push–pull donor–acceptor interactions stimulate strong fluorescence in the visible spectral range (up to Φ = 0.65 for 7) and induce significant changes in the photophysical properties associated with the acid-base equilibria (up to a 50-fold increase in the fluorescence intensity). pKa values in aqueous and mixed solutions (v/v H2O:EtOH 99:1, 50:50), appear suitable for monitoring acidic pH in solution. The most promising candidates were immobilised in thin polymer matrices by the spin coating technique to form fluorescent sensing materials – optodes, and examined as novel pH-sensitive fluoroionophores. In the liquid membrane environment, dyes exhibited significant increase of the apparent pKas by almost 4 units. Bright and blue emissive thin films showed pH response and dynamic range around pKa = 5, making them suitable for a wide range of optical sensing applications.
benzimidazole ; quinoline ; pH probe ; pH sensor ; fluorescence ; fluoroionophore
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Podaci o izdanju
227
2020.
117588
15
objavljeno
1386-1425
1873-3557
10.1016/j.saa.2019.117588