Synthesis of Pd(II), Ag(I), Pt(IV), and Hg(II) Complexes with Nifuroxazide, Their Structure, DFT Modeling, and Antimicrobial and Anticancer Activity

New mononuclear complexes of Pd(II), Ag(I), Pt(IV), and Hg(II) with nifuroxazide were synthesized by the reaction of the metals salts with the drug. The complexes were characterized by elemental and thermal analysis and FT-IR, 1H NMR, and UV–Vis spectra. Stoichiometry of the complexes was determined to be 1: 2. Nifuroxazide (Nif.) drug is coordinated to the metal ions as a bidentate ligand via oxygen and nitrogen atoms of the C=O and hydrazone groups. Density functional theory (DFT) calculations were carried out at the B3LYP levels with LANL2DZ basis set for Ag(I) and Hg(II) ions, LANL2MB basis set for Pd(II) and Pt(IV) ions, and 6-31G(d,p) basis set for the other atoms. The complexes had high thermal stability. Tests for anticancer activity, breast cancer cell line (MCF7), demonstrated that Hg(II), Pt(IV), and Pd(II) metal complexes had higher activity than the free ligand.