Synthesis, characterization of biologically active N, N’ - Bis(4-benzeneazosalicylidene)-o-phenylenediiminatocobalt(ii) complex

Abstract

A Schiff base was prepared as reported, its cobalt(II) complex was  synthesized by refluxing ethanolic mixture of the prepared schiff base and cobalt(II) chloride. The cobalt(II) Schiff base complex synthesized is brown, of percentage yield 65% and has decomposition temperature of 258oC. The Schiff base and N, N’ - bis(4-benzeneazo salicylidene)-o-phenylenediiminatocobalt(II) complex were characterized by solubility, melting point/decomposition temperature, molar conductivity, elemental analysis, IR spectra, bioassay and potentiomentry. The Schiff base and its
cobalt(II) complex are slightly soluble in methanol and ethanol but are readily soluble in DMSO and DMF. The molar conductance measurement of the complex determined is 4.6 ohm-1cm2mol-1, revealing its non electrolytic nature. The infrared spectral data of the ligand showed a band
at1590cm-1, which is attributed to v(C=N) stretching frequencies. The same band is observed in the synthesized cobalt(II) Schiff base complex, suggesting that the Schiff base is coordinated to the cobalt(II) Schiff base complex. The bands in the regions 585cm-1 and 511cm-1 in the complex are assigned to v(Co-N) and v(Co-O) stretching vibrations confirming the coordination of the Schiff base to the manganese(II) ion. The elemental analysis result of the complex is consistent with 1:1 metal to Schiff base ratio. The dissociation constant of the determined is 11.67, indicating a week acid. The average number of Schiff base coordinated to cobalt ion is one, the stability constant and Gibbs free energy of the complex  compound are 3.1x1011 and -64.15 KJmol-1, respectively, suggesting that the complex is very stable. The antifungal and antibacterial tests carried out on the Schiff base and its iron(II) complex showed good activity.

Keywords: 4 –(Benzeneazo) Salicylaldehyde, Potentiometry, complex  compound, schiff base, molar conductance and solubility.