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Abstract
The mixed drugs of paracetamol (PCM) and niacin (NCT) complexes of the form [Co(PCM)(NCT)H2OCl], [Fe(PCM)(NCT)SO4], and [Mn(PCM)(NCT)SO4] were synthesized by direct combination through refluxing and characterized using melting point/decomposition determination, solubility, conductivity, magnetic moment measurement, percentage metal analysis, and electronic and infrared spectroscopies. The lone drugs and complexes were also tested in-vitro against clinical bacteria. The strains- Staphylococcus aureus, Bacillus cereus (Gram-positive); Pseudomonas aeruginosa, Escherichia coli (Gram-negative) and Aspergillus niger, Fusarium species (fungi) were employed. Quickprep tool entrenched in molecular operating environments (MOE) software was used for the optimization of the compounds and the descriptors obtained were reported. The complexes’ infrared spectra revealed their bidentate nature, indicating paracetamol binding sites with metal ions as oxygen of carbonyl (C=O) and hydroxyl (O–H) groups; and to the niacin as the nitrogen (N) of pyridine ring and carbonyl oxygen (C=O) atoms. All the complexes assumed an octahedral geometry as supported and suggested by electronic spectra, magnetic moments, and percentage metal analysis. Conductivity measurements also established the covalent nature of the complexes, with the values range 13.78–18.35 Ω−1cm2mol−1. The antimicrobial screening revealed that the Mn(II) complex has the greatest antibacterial potency and fungicidal strength with inhibitory values (30.00–36.67 mm) and (36.67–38.33 mm) respectively, compared to others. The calculated descriptors also revealed that the studied compounds possess antimicrobial activities and this was further supported by molecular docking studies with the calculated binding affinity for the Co(II) complex, Fe(II) complex, and, Mn(II) complex against all the studied targets were − 4.89 kcal/mol, − 5.52 kcal/mol and − 5.83 kcal/mol (PDB ID: 2C1G); − 5.18 kcal/mol, − 5.42 kcal/mol and − 5.97 kcal/mol (PDB ID: 6TY6) and − 5.57 kcal/mol, − 6.17 kcal/mol and − 7.55 kcal/mol (PDB ID: 4WMZ) respectively. The complexes were good potential antibacterial and antifungal candidates with broad-spectrum as corroborated by molecular docking studies. Article Highlights New metal(II) mixed-drugs complexes of acetaminophen and niacin were prepared and characterized. In-vitro antimicrobial and molecular docking studies of the complexes were done. The complexes possessed good antibacterial and antifungal activities.