New 2H-[1,2,3]triazolo[4,5-e][1,2,4]triazolo[1,5-a]pyrimidine derivatives as luminescent fluorophores for detection of nitroaromatic explosives

A number of D-pi-A type dyes on the basis of new 2H[1,2,3]triazolo[4,5-e][1,2,4]triazolo[1,5-a]pyrimidines, bearing various electron-donating carbazole and triphenylamine fragments, have been studied as sensing fluorophores. Fluorescence studies have demonstrated that emission spectra of these compounds in acetonitrile are sensitive to the presence of nitroaromatic explosives, such as 2,4-dinitroanisole (DNAN), picric acid (PA), styphnic acid (SA), 1,3,5-triethoxy-2,4,6-trinitrobenzene (TETNB), 2,4-dinitrotoluene (DNT), 2,4,6-trinitrotoluene (TNT) and nitrobenzene (NB). Detection limits of fluorophores for DNAN, PA, SA, TETNB, DNT and TNT proved to be in the range from 4.82x10(-1) to 2.96x10(-3) mol/L, 2.10x10(-3) to 5.98x10(-5) mol/L, 1.26x10(-1) to 2.02x10(-4) mol/L, 1.58 x 10(-1) to 1.62x10(-3) mol/L, 1.26x10(-1) to 5.61x10(-4) mol/L and 9.01x10(-2) to 2.77x10(-3) mol/L, respectively. Selective fluorescence quenching response, including a sharp color change under UV irradiation (especially for PA, SA and DNT), makes these compounds promising fluorescence chemosensors for nitroaromatic explosives. (C) 2016 Elsevier Ltd. All rights reserved.