Ultrasensitive Detection and Photodegradation of Naproxen in Water via a Cationic [Co(BPMEDA)Cl₂]₂²⁺ Coordination Network

Pharmaceutical pollutants are increasingly recognized as emerging contaminants in aquatic ecosystems, raising urgent concerns for both environmental and human health. The development of multifunctional materials capable of simultaneously detecting and degrading such compounds is therefore of great significance. In this study, we report the synthesis and detailed characterization of a new cobalt-based hydrogen-bonded coordination polymer, {[Co(BPMEDA)Cl2]22+ 2NO3−} (Co-CP), derived from Co(II) ions and the N,N′-bis(2-pyridylmethyl)-1,2-ethylenediamine tetrahydrochloride dihydrate (BPMEDA) ligand. The structural integrity and compositional analysis of the Co-CP were confirmed using a comprehensive array of advanced characterization techniques, including single-crystal X-ray diffraction (SCXRD), energy-dispersive X-ray spectroscopy (EDAX), powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared spectroscopy (FTIR), and elemental mapping. Stability studies revealed that Co-CP remains robust under diverse pH conditions and exhibits excellent water stability upon prolonged immersion. The photoluminescence properties of Co-CP were explored for the detection of six biomarkers, among which the nonsteroidal anti-inflammatory drug naproxen (NPX) demonstrated the highest sensitivity with remarkable limits of detection (LOD). Furthermore, Co-CP exhibited outstanding photocatalytic degradation performance, achieving a degradation efficiency of 93.91% for NPX under optimized conditions. This dual functionality, combining sensitive fluorescence sensing and efficient photocatalytic degradation, underscores the potential of Co-CP for addressing environmental challenges posed by pharmaceutical contaminants. The results position Co-CP as a promising material for the detection and removal of pharmaceutical pollutants in aqueous systems, offering a sustainable and innovative solution for mitigating pharmaceutical waste in water and promoting environmental health. These findings contribute significantly to the development of multifunctional CP-based platforms for environmental remediation.