A highly stable and efficient benzothiadiazole-based fluorescence sensor for salicylaldehyde in aqueous solution

Abstract

A Cd^II-based coordination polymer with the formula [Cd(BIBT)(3,4-TDC)]_n (JXUST-27, BIBT = 4,7-bi(1H-imidazol-1-yl)benzo-[2,1,3]thiadiazole and 3,4-H₂TDC = thiophene-3,4-dicarboxylic acid) was synthesized under solvothermal conditions. Single-crystal structural determination reveals that JXUST-27 adopts a two-dimensional structure with sql topology. JXUST-27 can keep stable up to 317 °C and in common solvents. In particular, JXUST-27 exhibits excellent stability when the samples are immersed in aqueous solutions with pH values of 2–13 or in boiling water for 24 hours. Furthermore, JXUST-27 could selectively detect salicylaldehyde (SA) through turn-off effect with a detection limit of 0.087 μM. More importantly, JXUST-27 represents the first Cd^II coordination polymer based fluorescence sensor toward SA in aqueous solution. In addition, the portable fluorescent film and light-emitting diode lamp based on JXUST-27 were further developed for the detection of SA.