A design for detecting phosphate ions in aqueous solution by luminescent Tb-coordination polymer

Abstract

Phosphate usually plays an important role not only in biological processes but also in environmental pollution, and therefore there is an urgent need for a simple, quick and efficient method to detect phosphate ions. For this design, a new terbium coordination polymer (Tb-CP) has been prepared under hydro-solvothermal conditions using 3,3′-((5-carboxy-1,3-phenylene)bis(oxy))dibenzoic acid (H3cpboda) in the existence of Tb(NO3)3‧6H2O. It was studied by infrared spectroscopy (IR), single crystal X-ray diffraction, thermogravimetric analysis (TGA), and fluorescence method. Structurally, the Tb-CP gives a 2D network based on binuclear Tb(III) units. Optically, the Tb-CP is prepared as a colloidal nanoparticle suspension for detecting phosphate in water solution. Namely, the suspensions show intense green emissions gradually disappear with the addition of PO43− ions, indicating that the Tb-CP can rapidly, sensitively and reversibly detect phosphate ions in aqueous solutions. This can be applied in pollutant monitoring with a limit of detection down to 4.53 × 10−8 M (0.0096 ppm). Furthermore, a convenient method is successfully set to observe PO43− ions in applications.