SYNTHESIS AND THERMAL ANALYSIS OF MIXED-LIGAND COMPLEXES OF POTASSIUM 2-(4-ISOBUTYLPHENYL) PROPANOATE WITH 3D-METAL NITRATE SALTS AND ACETAMIDE

This study reports the synthesis, structural characterization, and thermal analysis of mixed-ligand complexes formed between potassium 2-(4-isobutylphenyl) propanoate (the potassium salt of ibuprofen), 3d-metal nitrates (Mn(II), Co(II), Ni(II), Cu(II), and Zn(II)), and acetamide. The complexes were synthesized under mild, reproducible conditions in ethanol through coordination interactions between the ligands and the metal centers. The resulting compounds were characterized using elemental analysis, IR spectroscopy, powder X-ray diffraction (PXRD), and thermogravimetric/differential scanning calorimetry (TGA/DSC) techniques. Shifts in the ν(C=O) and ν(C–O) stretching frequencies in the IR spectra confirmed the coordination of carboxylate oxygen atoms to the metal ions. Thermal analysis revealed that the complexes lost their crystal water molecules at 100–150 °C, followed by decomposition of the organic ligands between 250–450 °C. The final residues were identified as corresponding metal oxides (MnO, CoO, NiO, CuO, ZnO). These results demonstrate the successful formation of thermally stable mixed-ligand complexes based on ibuprofen potassium salt. The synthesized complexes show promising structural and thermal stability, indicating their potential as drug-delivery carriers or biologically active materials.