Luminescent Cd coordination polymer based on thiazole as a dual-responsive chemosensor for 4-nitroaniline and CrO42- in water

Abstract

A novel highly fluorescent cadmium metal-organic framework, [Cd (DPTTZ) (OBA)] (IUST-3), synthesized by using two linkers 2, 5-di (pyridine-4-yl) thiazolo [5, 4-d] thiazole (DPTTZ) and 4, 4'-oxybis (benzoic acid) (OBA) simultaneously, which exhibits a two-dimensional framework. The characteristics of this Cd-MOF were investigated by single-crystal X-ray diffraction, Fourier transform infrared spectroscopy, elemental analysis, powder X-ray diffraction, and thermogravimetry analysis. The IUST-3 exhibits excellent luminescence property and good stability in water. Luminescent experiments indicate that the IUST-3 has remarkable sensitivity and selectivity for the detection of 4-nitroaniline (4-NA), and CrO₄^2- anion with K_SV = 1.03 × 10⁵ M^-1 (4-NA) and K_SV = 2.93 × 10⁴ M^-1 (CrO₄^2-) and low limit of detection 0.52 µM (4-NA) and 1.37 µM (CrO₄^2-). In addition, the possible fluorescence quenching mechanism was explored in this paper.