Multi-responsive luminescent complex for Fe3+, Cr2O72− and CrO42− species in aqueous solution based on aromatic polycarboxylic acid and imidazole-containing ligand: synthesis, crystal structure and selective detection

Abstract

One Cadmium(II)-based complex, [Cd(LBIX)(HEA)]n (1), was synthesized using 4,4′-bis((1H-imidazol-1-yl)methyl)-1,1′-biphenyl (LBIX) and 1,2-phenylenediacetic acid (H2HEA) as ligands. The analysis of the single crystal structure reveals that 1 possesses a ladder-like chain structure, which extends into a 3D architecture through π···π interactions. 1 was identified through powder X-ray diffraction analysis (PXRD), elemental analysis (EA), infrared spectroscopy (IR) and thermogravimetric analysis (TGA). It can be seen from the luminescence experiment that 1 has high Ksv value (Cr2O72−: 1.51 × 104 M−1, CrO42−: 1.16 × 104 M−1 and Fe3+: 1.26 × 104 M−1) and lower detection limit (Cr2O72−: 1.14 μM, CrO42−: 1.88 μM and Fe3+: 1.14 μM), it is utilized as a multi-response sensor to recognition Fe3+, CrO42− and Cr2O72− in an aqueous solution. Mechanisms in which fluorescence quenching occurs have been examined using techniques such as PXRD, UV–vis absorption spectra, scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). Due to its excellent selectivity, high sensitivity and strong stability, it is suitable for detecting Fe3+, CrO42− and Cr2O72− ions as a fluorescent probe.