Role of hydrazone substituents in determining the nuclearity and antibacterial activity of Zn(ii) complexes with pyrazolone-based hydrazones

• DOI: 10.1039/d2dt02430f
• Publication Date: 2022-08-24T09:30:56Z
• Authors: Fabio Marchetti; Riccardo Pettinari; Federico Verdicchio; Alessia Tombesi; Stefania Scuri; Sonila Xhafa; Laura Olivieri; Claudio Pettinari; Duane Choquesillo...; Amalia García-García; Antonio Rodríguez...; Agustín Galindo
• Keywords: Hydrazone; Coordination complex; Proton NMR

Hydrazones and their metal derivatives are very important compounds in medicinal chemistry due to reported variety of biological activities, such as antibacterial, antifungal anticancer action. Five hydrazone-pyrazolone ligands H2Ln (n = 1-5) were prepared fully characterized tautomerism was investigated the solid state solution. zinc(II) complexes 1-5 composition [Zn(HLn)2] 1 2), [Zn(HLn)2(H2O)2] 3 5) [Zn(HL4)2]n synthesized by elemental analysis, IR, 1H, 19F, 13C, 15N NMR spectroscopy, ESI mass spectrometry. In addition, structures two three determined single-crystal X-ray diffraction. The H2L2 H2L4 exist both NH,NH tautomeric form. Complexes 2 mononuclear compounds, while complex 4 is a one-dimensional coordination compound. Density functional theory (DFT) calculations carried out on proligands, anions all zinc complexes, confirming experimental results, supporting IR assignments giving proofs diaqua structure 5. antibacterial activity free Zn(II) established against Escherichia coli Staphylococcus aureus, strong efficiency has been found for particularly polynuclear 5, latter containing ligand with aliphatic fluorinated substituents able compromise permeability disrupt bacterial cell membrane.