Synthesis and characterization of cobalt (II), nickel (II) and copper (II) complexes of Cyclohexylamine-N-methyl Mannich base ligands

Abstract

Three Mannich base ligands, Cyclohexylamine-N-methylurea (CHMU), Cyclohexylamine-Nmethylacetamide (CHMAA) and Cyclohexylamine-N-methylacetone (CHMA) and their cobalt(II), nickel(II) and copper(II) complexes were synthesized and chelating properties investigated with the view to determine the coordination modes and the stoichiometric ratio of the metal complexes. The Mannich ligands, CHMU, CHMAA and CHMA were prepared by the reaction of cyclohexylamine, formaldehyde and urea; cyclohexylamine, formaldehyde °C and acetone; cyclohexylamine, formaldehyde and acetamide respectively at 25 . They were characterized using infra-red (IR) spectroscopy. Their cobalt(II), nickel(II) and copper(II) complexes were equally prepared and characterized by infrared and UV-Visible spectroscopy. The solubilities of the ligands and their complexes in common solvents were also investigated. All the metal(II) complexes are stable in air and decomposed without melting at °C temperature>300 . The infra-red spectra of the ligands show absorption bands in the region INTRODUCTIONThere had been increasing studies of Mannich base complexes over the years due to the selectivity and sensitivity of the ligands to various metal ions.The quest of a coordination chemist is directed at designing ligands and acquiring more understanding of the ways in which they complex with metal ions. Metal ion complexes act as catalysts and it is necessary to design more effective catalysts for a variety of metal catalyzed