New complexes of chelating Schiff base: Synthesis, spectral investigation, antimicrobial, and thermal behavior studies

Abstract

The new bidentate Schiff base ligand (E)-1-(4-((E)-(4-(diethylamino)-2-hydroxybenzylidene)amino)phenyl)ethanone oxime [HL], has been synthesized via condensation equal amounts of 1-(4-aminophenyl)ethanone oxime and 4-Diethylaminosalicylaldehyde. The title ligand characterized by using (IR, UV-Vis) spectroscopies, (1H, 13C) NMR spectra, Mass spectrum and X-Ray crystallography. Chelated complexes of prepared ligand with Co(II), Ni(II) and Cu(II) ions, have been also prepared with a ratio of (1:2), (M:L) and characterized by (IR, UV-Vis) spectroscopies, magnetic susceptibility, molar conductivity and flame atomic absorption measurements. Results of spectral studies proved the chelation behavior of this ligand, which coordinated to metal ions as a monobasic N,O bidentate ligand, via imine and phenolic oxygen atom, after losing its proton. Tetrahedral geometry has been proposed for Co(II) complex and square planar geometry has been proposed for Ni(II) and Cu(II) complexes, respectively. The analysis studies of (TG/DTG/DTA) data reflected potential and good thermal stability of [HL] and its metal complexes. We also obtained the biological activity of the prepared compounds against two Gram-positive bacteria (Staphylococcus aureus & Staphylococcus epidermidis), four Gram-negative bacteria (Salmonella, E-coli., Pseudomonas aeruginosa & Klebsiella spp.) and one fungal (candida albicans).