Structure Studies of the Prepared Novel Hydrazone Schiff's Base Complexes Using Spectroscopic, Thermal Analyses and Their Biological Activities

The complexing behavior of benzoylhydrazone Schiff's base (A1), with the IUPAC name (2(1-hydrazonoethyl)phenol), towards the transition metal ions, namely, Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II), Hg(II), Ce(IV), and UO2(II), has been examined by elemental analyses, magnetic measurements of some of them, electronic spectra, FT-IR, 1H-NMR, and 13C-NMR. Thermal properties and decomposition kinetics of all complexes are investigated. The interpretation of kinetic parameters of thermal decomposition stages of some of them has been evaluated using Coats-Redfern equation. The antifungal activities of the free ligand and its metal complexes have been tested in vitro against two types of fungi: Aspergillus fumigatus, RCMB 02568; Candida albicans, RCMB 05036. Besides, two gram-positive (Bacillus subtilis, RCMB 010067; Streptococcus pneumoniae, RCMB 010010) and two gram-negative (Escherichia coli, RCMB 010052; Pseudomonas aeruginosa, RCMB 010043) bacteria were used as test organisms in order to assess the complexes' antimicrobial potential. It is clear from this survey that the A1 complexes are of high biological activities as antifungal, in which Cu-A1 and Co-A1 are the most efficient complexes in a level more or less approaches that of the amphotericin standard. It also indicates that the Cu-A1 and Mn-A1 have the largest biological effects on gram-positive bacteria of both kinds, and that Cu-A1 complex has a more effect (32.4±0.30) or of the same order of magnitude (23.8±0.20) as that of the ampicillin standard (23.8±0.2).