Fabrication of cu(II)-coordination polymer and its Mn-doped composites for luminescent detection of Novaluron pesticide, La3+ and TEA

Abstract

A new copper-based coordination polymer, [Cu₃(Timb)₂(OA)₂·6(H₂O)]ₙ (1), was synthesized using 1,3,5-tris[(1H-imidazol-1-yl)methyl]benzene (Timb) and orotic acid (OA) ligands. The structure of (1) was characterized through single-crystal X-ray diffraction (SCXRD), Thermogravimetric analysis (TGA), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDX), and powder X-ray diffraction (PXRD). To enhance its luminescent properties, the polymer was doped with MnO₂, MnO@Cu-CP-2 (2), which was further characterized by FTIR, PXRD, TGA, and SEM-EDX. Both the undoped (1) and doped (2) materials exhibited promising luminescent properties for detecting triethylamine (TEA), La³⁺ ions, MnO₄⁻, and hazardous pesticides such as Novaluron (NVR). Detection limits for (1) were determined to be 0.1405 ppm, 0.2321 ppm, 0.6601 ppm, and 0.7242 ppm for TEA, La³⁺, MnO₄⁻, and NVR, respectively. Upon MnO₂ doping, (2) demonstrated enhanced luminescent sensing capabilities, with detection limits of 0.4067 ppm, 0.6625 ppm, 0.9363 ppm, and 0.9862 ppm for the same analytes. The study also provides detailed insights into the luminescence mechanisms and the role of MnO₂ incorporation in enhancing the sensing performance, underscoring the potential of (2) for superior analytes detection compared to the undoped polymer.