ABSTRACT

Schiff base derived from 2-aminophenol and 3-formyl-2-hydroxy-6-methoxyquinoline and its Mn(II) and Fe(II) complexes were synthesized and characterized by melting point and decomposition temperature, elemental analysis, molar conductivity, infrared (IR) spectral analysis, atomic absorption spectroscopy (AAS) analysis, solubility test, and magnetic susceptibility. The Fourier-transform infrared spectroscopy (FTIR) spectral data of the Schiff base determined showed a band at 1622 cm −1 and this was assigned to the v (C=N), which is a feature of azomethine group. The same band was observed to shift to lower frequencies 1577 and 1599 cm −1 in the complexes suggesting coordination of the Schiff base with the respective metal(II) ions. Molar conductance values 14.58 and 12.65 Ω −1 •cm 2 •mol −1 show that the metal complexes were non-electrolyte in nature. The magnetic susceptibility of the complexes was determined and the gram magnetic susceptibility of the complexes was found to be positive, revealing that they are paramagnetic. The elemental analysis of the complexes for C, N and H determined suggested 1:1 metal to ligand ratio. The result of the antimicrobial studies showed that, the metal(II) complexes exhibited better antibacterial and antifungal activity than the Schiff base.

The complexes of iron (II) and nickel (II) with schiff base derived from benzoin and 2-amino benzoic acid have been prepared. Solubility, melting point, decomposition temperature, conductance measurement, infrared (IR) and UV-Visible spectrophotometric studies were used in characterizing the compounds. The melting point of the schiff base determined is 120 o C. The decomposition temperatures of iron (II) and nickel (II) complexes are 152 o C and 155 o C, while the molar conductance values are 11.2 and 10.7 ohm-1 cm 2 mol-1 , respectively. The UV-Visible spectrophotometric analysis revealed 1:1 (metal-ligand) stoichiometry for the two complexes.

No abstract

The interaction of ethanolic solution of semicarbazide hydrochloride, benzyldehyde and morpholine yielded N-(I-Morpholinobenzyl) Semicarbazide Schiff base. The Schiff base complexes of manganese(II) and iron(II) were synthesized by refluxing the mixture of ethanolic solutions of the Schiff base and metal(II) chlorides, respectively. These complexes were characterized by gravimetry, spectrophotometry, potentiometry, molar conductance and infrared analyses. The Schiff base and the complex compounds are not soluble in water, slightly soluble in most common organic solvents but are readily soluble in methanol and ethanol. The molar conductance of the manganese(II) and iron(II) Schiff base complexes measured are 3.78 and 6.90 ohm-1 cm 2 mol-1 , respectively, indicating their non-electrolytic nature. The potentiometric studies revealed a pKa of 5.40 for the Schiff base. The standard Gibb's free energy of Mn(II) and Fe(II) Schiff base complexes determined are-65.79KJmol-1 and-60.35KJmol-1 , respectively. The ratio of metal ion to Schiff base determined potentiometrically and spectrophotometrically for the complex compounds is 1: 2. The IR spectrum of the Schiff base shows bands observable in the two Schiff base complex compounds, indicating the coordination of the Schiff base to the copper ion.