New "turn-off" fluorescence sensors to detect vapors of nitro-explosives on the basis of 4,6-bis[5-(heteroaryl)thiophen-2-yl] substituted 5-(4-tert-butylphenyl)pyrimidines

Abstract

New D--A--D type dyes based on compounds of the pyrimidine family, bearing thiophene linkers, have been designed, synthesized and characterized. The fluorescence behavior of these fluorophores have been evaluated for fifteen nitro compounds. The detection limits for these fluorophores in relation to nitro explosives in acetonitrile solution proved to be in the range from 10 -1 to 10 -6 mol/L. The sensor prototypes for handheld sniffer Nitroscan (Plant Promautomatika, Ekaterinburg, Russia), based on these fluorophores, have been fabricated and used, as illustrated by reversible and sensitive fast detection of nitrobenzene in vapor phase concentrations up to 0.06 ppm.