Novel pyrenecarboxaldehyde-4-methyl-3-thiosemicarbazone (1), pyrenecarboxaldehyde-4-(4- ethylphenyl)-3-thiosemicarbazone (2) and pyrenecarboxaldehyde-4,4-dimethyl-3-thiosemicarbazone (3) have been synthesized and characterized by elemental analysis, FT-IR, ¹H NMR MS techniques. Their fluorescence and recognition properties to the mercury ion were studied by the fluorescence excitation and emission spectra. With adding mercury ion into their solutions respectively, their fluorescence emission intensities at different characteristic wavelength changed continually. Hence the ratiometric fluorescence measurement was used for detecting the complex process. It was found that a 1∶1 stoichiometry complex is formed between the mercury ion and the three compounds with the association constants were 4.57×10⁴, 5.54×10⁴ and 2.12×10⁴ L/mol, respectively. And the detection limits of the mercury ion were 4.56×10^－6, 2.61× 10^－6 and 5.49×10^－6 mol/L.

Key words: thiosmicarbazone, pyrene derivative, cation recognition, synthesis, fluorescence spectrum