Preparation and spectral and biological investigation of vic-dioxime ligands containing piperazine moiety and their mononuclear transition-metal complexes

Two vic-dioxime ligands, N-(4-benzylpiperazine-1-yl) p-tolylglyoxime (L1H2) and N,N′-bis(4-benzylpiperazine-1-yl) glyoxime (L2H2) containing piperazine moieties were synthesized, and their Ni(II) Cu(II) Co(II) and Zn(II) complexes were obtained. The ligands were characterized by elemental analysis, Fourier transform-infrared (FT-IR) ultraviolet-visible NMR (1H, 13C, and heteronuclear multiple-bond correlation) and electrospray ionization (ESI) mass spectrometry. The isolated complexes were characterized by a combination of elemental analysis, IR, UV-vis, and ESI mass spectrometry and in the case of Ni(II) and Zn(II) complexes by 1H and 13C NMR spectroscopy. The electrochemical behaviors of the ligands and their complexes were studied by cyclic voltammetry (CV) in dimethylsulfoxide solution containing tetrabutylammoniumtetrafluoroborate (TBATFB). The antibacterial activity was also studied against S. aureus ATCC 25923, S. aureus ATCC 29213, S. mutans RSHM 676, E. faecalis ATCC 29212, E. coli ATCC 25922, and P. aeruginosa ATCC 27853. The antimicrobial test results indicated that all the compounds have good antibacterial activity against P. auriginosa ATCC 27853 bacteria and were as effective as ampicilin. [Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resources: Full experimental and spectral details.] © 2013 Copyright Taylor and Francis Group, LLC.