SYNTHESIS AND CHARACTERIZATION OF COBALT(II) COMPLEXES WITH SCHIFF BASE DERIVED FROM SALICYLALDEHYDE AND ETHYLENEDIAMINE
Abstract
ABSTRACT
This study focused on the synthesis and characterization of cobalt(II) complexes with a Schiff base ligand derived from salicylaldehyde and ethylenediamine. Schiff base ligand, N,N′-bis(salicylidene)ethylenediamine (salen), was synthesized via condensation reaction between salicylaldehyde (20 mmol) and ethylenediamine (10 mmol) in methanolic medium, yielding a pale yellow crystalline solid with melting point of 84-86°C and percentage yield of 74.42%. The cobalt(II) complex was prepared by reacting the synthesized ligand with cobalt(II) chloride hexahydrate, producing a brown solid complex with melting point of 186-190°C and yield of 66.75%. Characterization was performed using infrared (IR) spectroscopy, melting point determination, and solubility tests. IR spectral analysis confirmed the formation of the azomethine (C=N) functional group at 1610 cm⁻¹ in the free ligand, which shifted to 1636 cm⁻¹ upon complexation. New absorption bands at 752.9 cm⁻¹ and 682.1 cm⁻¹ corresponding to M-N and M-O vibrations respectively confirmed coordination through both nitrogen and oxygen donor atoms. The complex exhibited enhanced thermal stability and altered solubility compared to the free ligand, indicating successful metal-ligand coordination. The results demonstrate that the salen-type ligand acts as a bidentate chelating agent forming stable complexes with cobalt(II) ions
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