Complexation of 2-acetylpyridine- and 2-benzoylpyridine-derived hydrazones to copper(II) as an effective strategy for antimicrobial activity improvement

Complexes [Cu(2AcPh)Cl]·2H2O (1), [Cu(2AcpClPh)Cl]·2H2O (2), [Cu(2AcpNO2Ph)Cl] (3), [Cu(2BzPh)Cl] (4). [Cu(2BzpClPh)Cl] (5) and [Cu(2BzpNO2Ph)Cl] (6) were obtained with 2-acetylpyridine-phenylhydrazone (H2AcPh), 2-acetylpyridine-para-chloro-phenylhydrazone (H2AcpClPh), 2-acetylpyridine-para-nitro-phenylhydrazone (H2AcpNO2Ph), 2-benzoylpyridine-phenylhydrazone (H2BzPh), 2-benzoylpyridine-para-chloro-phenylhydrazone (H2BzpClPh) and 2-benzoylpyridine-para-nitro-phenylhydrazone (H2BzpNO2Ph). The hydrazones showed poor antibacterial effect against Staphylococcus aureus, Enterococcus faecalis and Pseudomonas aeruginosa but demonstrated significant antifungal activity against Candida albicans. Upon coordination to copper(II) the antibacterial and antifungal activities appreciably increased. H2AcpClPh, H2BzpClPh and their copper(II) complexes (2) and (5), respectively, were as active as fluconazole against C. albicans.

[Cu(2AcPh)Cl]·2H2O (1), [Cu(2AcpClPh)Cl]·2H2O (2), [Cu(2AcpNO2Ph)Cl] (3), [Cu(2BzPh)Cl] (4). [Cu(2BzpClPh)Cl] (5) and [Cu(2BzpNO2Ph)Cl] (6) were obtained with 2-acetylpyridine-phenylhydrazone (H2AcPh), 2-acetylpyridine-para-chloro-phenylhydrazone (H2AcpClPh), 2-acetylpyridine-para-nitro-phenylhydrazone (H2AcpNO2Ph), and the corresponding 2-benzoylpyridine-derivatives (H2BzPh, H2BzpClPh, H2BzpNO2Ph). Upon coordination to copper(II) the antimicrobial activities appreciably increased. H2AcpClPh, H2BzpClPh and complexes (2) and (5) were as active as fluconazole against Candida albicans.Figure optionsDownload as PowerPoint slideHighlights
► Copper(II) complexes were obtained with pyridine-derived hydrazones.
► Hydrazones showed poor antibacterial activity.
► Hydrazones presented significant antifungal activity against Candida albicans.
► Upon coordination to copper(II) the antimicrobial activities appreciably increased.
► Some of the studied compounds were as active as fluconazole against C. albicans.