Anti-solvatochromic fluorescence of thiazole [5, 4-d] thiazole by forming hydrogen bond network and its application in fast detection of trace water

Abstract Thiazole [5, 4-d] thiazole (TTz) derivatives are a novel type of fluorophore which shows great potential in fluorescent and photochemical applications. In this paper, a TTz derivative (named TTz 1) was synthesized and studied. TTz 1 exhibits almost no fluorescence in organic solvents whereas has 300-fold brighter fluorescence in water. The experiments of nuclear magnetic resonance (NMR), differential scanning calorimetry (DSC), Raman spectroscopy suggested that the formation of hydrogen bond network is the main reason for such a special anti-solvatochromic effect. This unique property makes TTz 1 have a good recognition of water with a fast response within 10 s. pH, metal ions, amino acids and common reactive species had no influence on the detection of water. The fluorescence intensity of TTz 1 in THF was linearity with the water in the range of 0%-90.0%; the detection limit was calculated 0.019%. The proposed method was successfully applied for detection of water content in honey and analytical grade organic solvent. Moreover, it also exhibits good electrochemical properties, so, the detection of water content by cyclic voltammogram in the electrochemical channel also could be achieved. This is the first time to find the hydrogen bond network effect of TTz derivatives, which is very helpful for exploring further on scientific problem of hydrogen bond network and designing many novel probes based on TTz derivatives.