New coordination insights into paracetamol and 1,10-phenanthroline metal complexes: Synthesis, characterization, DFT calculations, and antimicrobial study

Seven novel bidentate metal complexes of paracetamol (Para) and 1,10- Phenanthroline (Phen), with the general formula [M(Para)(Phen)2]Cl2 (M(II) = Mn, Fe, Co, Ni, Cu, Zn, and Cd), were synthesized in the present work and characterized by metal content, conductivity, melting point, elemental analysis, magnetic moment measurements, and UV-Vis and FT-IR spectroscopies. The molar conductance values further indicate that the complexes are electrolytic in nature. Paracetamol coordinates through its carbonyl (C=O) group and the amide nitrogen, whereas phenanthroline binds via its (N,N) donor atoms; therefore, both ligands act as bidentate, neutral donors. All complexes exhibit octahedral geometry, with one paracetamol and two phenanthroline ligands surrounding the metal ion. The antimicrobial activity was evaluated against two Gram-positive and two Gram-negative bacteria, as well as the fungus Candida albicans. DFT calculations were performed for selected complexes to obtain optimized structuresand analyze electronic orbitals and related parameters.