Mechanosynthesis, Characterization, And Antimicrobial Evaluation of Cadmium(Ii), Nickel(Ii), Iron(Iii), And Chromium(Iii) Chelates Formed with Paracetamol and Aspirin.

Abstract

This study describes the mechanochemical synthesis of cadmium (Cd(II)), nickel (Ni(II)), and chromium (Cr(III)) as well as iron (Fe(III)) complexes with aspirin and paracetamol, achieved through simple grinding of their metal chlorides without the use of solvents. Additionally, these complexes were prepared using traditional solution-based methods for comparison. Both mechanochemical and conventional products were characterized by examining their solubility, melting points, conductivity, magnetic moments, and infrared (IR) spectra. The IR and analytical data indicated that the complexes formed were identical regardless of the synthesis method. Job's method analysis showed a 1:2 metal-to-ligand ratio for both aspirin and paracetamol complexes. High molar conductance values, ranging from 109.42 to 207.61 Ω^-1cm²mol^-1 for aspirin complexes and 77.32 to 100.22 Ω^-1cm²mol^-1 for paracetamol complexes, suggest their electrolytic nature in dimethylsulfoxide (DMSO). The complexes were soluble in dimethylformamide (DMF) and DMSO, with paracetamol complexes also dissolving in acetone, methanol, and diethylether (DEE), and aspirin complexes being soluble in methanol, DMF, and DMSO. Except for the Cr(III) complex, all aspirin complexes were insoluble in water. Magnetic moment values confirmed that all synthesized complexes were paramagnetic, except for the diamagnetic cadmium complexes. The complexes displayed higher thermal stability, decomposing between 163.7-198.3 °C, compared to their respective ligands which decomposed at 170 °C for paracetamol and 137 °C for aspirin. The antimicrobial activity of the ligands and their complexes was tested against two bacterial strains, Escherichia coli and Staphylococcus aureus, and two fungal strains, Mucus species and Candida species. The ligands exhibited limited activity against most organisms, whereas most complexes showed activity at all test concentrations, with paracetamol complexes being effective only at higher concentrations.