Multi-response luminescent sensor with phenylenediacetic acid and bis-triazole ligand for the detection of Cr(VI), Fe(III) and nitroimidazole antibiotics in aqueous solutions

A novel complex of [Zn(L)(HEA)]n (1) has been successfully synthesized by hydrothermal method based on the double ligands of H2HEA (H2HEA = 1,2-Phenylenediacetic acid) and L (L = 1,1′-((2,4,6-trimethyl-1,3-phenylene)bis(methylene))bis(1H-1,2,4-triazole)). The single crystal structure of the complex was analyzed by X-ray single crystal diffraction, indicating that complex 1 was stacked into a 3D crystal structure through intermolecular π···π and C-H···π weak interaction. The complex was characterized by elemental analysis, infrared spectroscopy, PXRD and TGA. Additionally, fluorescence experiments showed that complex 1 could be used as a fluorescent probe for detecting Fe(III), Cr(VI), and Metronidazole (MDZ), Ornidazole (ODZ), Dimetridazole (DTZ) in aqueous solutions. Detection limits were obtained for ions (3.2×10−7 M for Cr2O72−, 5.4×10−7 M for CrO42− and 3.6 × 10−7 M for Fe3+) and nitroimidazole antibiotics (1.3×10−7 M for MDZ, 9.7×10−8 M for ODZ and 4.4×10−8 M for DTZ). The possible fluorescence quenching mechanism has been studied in the paper.