No abstract

Schiff-oxime ligands characterized by the existence and participation of iminic-and oximic azomethine groups in coordination with metal ions [1-3]. Metal complexes of imineoxime have various applications in different scientific fields. It has been used as antimicrobial [4], antibacterial [5], antifungal [5,6] as well as anticancer [7]. Some of Schiff oxime derivatives have been used in extraction [8] and spectrophotometric determination [9] of metal ions. Imine-oxime complexes have been also found used as catalysts for selective oxidation of alcohols to ketones and aldehydes [10]. EXPERIMENTAL Chemicals have been procured from Fluka and Sigma-Aldrich. Shimadzu (FT-IR), 4800S spectrophotometer has been used to get FTIR spectra of prepared compounds (4000-400 cm-1 , KBr). Cary 100con. spectrophotometer has been used for electronic spectra of prepared compounds at wavelength 200-800 nm. Stuart digital SMP30 apparatus used for measuring melting points of compounds. Mass spectrum of H2L was performed on GC-MS QP-2010 (Shimadzu). NMR spectra of H2L in DMSO-d6 were recorded by Bruker DMX-500 spectrophotometer (300 MHz). Phoenix-986 AA spectrophotometer has been used to estimate the metal ions percentages.

Two new unsymmetrical imidazolium salts viz., [1-(4-ethylphenyl)-3-propyl-1H-imidazole-3-ium bromide] (3) and [1-(2,6-dimethylphenyl)-3-propyl-1H-imidazole-3-ium bromide] (4) have been synthesized via the reaction of propyl bromide with imidazole derivatives, [1-(4-ethylphenyl)-1Himidazole] (1) and [1-(2,6-dimethylphenyl)-1H-imidazole] (2) in absence of solvent. Then two new N-heterocyclic carbene silver complexes (5 and 6) were prepared through the reaction of imidazoluim salts (3 and 4) as a source of N-heterocyclic carbene with Ag2O by in situ method. These complexes can be used in the future as a transfer agent for preparing other transitional metal carbine complexes (NHCs) via transmetallation method. The formation of these compounds was confirmed by spectral analysis.

In present work, new tetra-dentate ligand, titled 3,5-bis ((E)-5-Bromo-2-hydroxy benzylidene amino) benzoic acid (H 3 L), was prepared via an acid-catalyzed condensation process. New four metallic ligand complexes with Co(II), Ni(II), Cu(II) and Zn(II) ions, were also prepared from the refluxing of equivalent moles. Ligand's structure and its complexes; were confirmed by numerous characterization methods, including Ultraviolet-Visible, Infrared, Mass Spectrometer, 1 H and 13 C Nuclear Magnetic Resonance spectra, atomic absorption, magnetic moments, and molar conductivity measurements. The results of the spectroscopic analyzes proved that the prepared ligand acts as tetradentate bi-ionic ligand and it was bonded to the metal ions by two nitrogen atoms of the two azomethine groups and by two oxygen atoms of the two phenolic hydroxyl groups after losing their two protons. Octahedral structure proposed to all prepared complexes. The (anti-bacterial) and (anti-fungal) activities of these compound were screened against (E. coli, S. aureus, Klebsiella spp., S. epidermidis,), and (Candida albicans). The results indicated that these compounds have moderated inhibition behavior. The activity of the prepared compounds against Acetyl Choline Esterase Enzyme (AChE) have also studied and the obtained data indicated the presence of different inhibition behavior.