Water-Driven Nanoarchitetonic Assembly of a Quinolone-Based Coordination Polymer for Efficient Dye Removal

Abstract 4-Quinolones are a class of heterocycles traditionally known for their biological properties. More recently, those derivatives have gained attention as versatile ligands for the construction of metal-centered molecular materials, such as coordination polymers (CPs), opening new possibilities for environmental applications. In this study, a novel dicarboxylated organic compound, 1-ethyl-4-oxo-1,4-dihydroquinoline-3,6-dicarboxylic acid ( H 2 L ), was synthesized and employed to construct zinc-based materials. The synthetic parameters (temperature, time, modulator type, and modulator/ligand precursor ratio) were systematically evaluated, notably highlighting the replacement of the conventional solvothermal solvent (DMF) with a greener alternative (H 2 O) to synthesize the Zn-based materials. Under optimized conditions, two new materials were obtained, namely Material 1 (synthesized in DMF) and Material 2 (synthesized in H 2 O). Additionally, Material 2 - [Zn(L)(H 2 O)] n - was obtained as single crystals and structurally characterized via synchrotron X-ray diffraction. As for the application, Material 2 demonstrated an adsorption capacity of 24.6 mg g -1 for the removal of the toxic dye methylene blue (MB). Different adsorption essays revealed that the Langmuir isotherm and pseudo-second-order kinetic model best described the behavior of Material 2 . This material achieved 100% selectivity toward the cationic dye (MB) and demonstrated excellent reusability, with only approximately 10% loss in removal efficiency over three adsorption/desorption cycles. Post-adsorption characterization provided valuable insights into the underlying interaction mechanisms. Together, these results highlight the potential of the developed quinolone-based coordination polymer as an efficient material for environmental remediation applications and underscore the relevance of further exploring this emerging class of compounds. Graphical Abstract