Cobalt(II) and copper(II) complexes with carboxylic acids, imidazole, and 2-methylimidazole

The compositions of [MIm(MeIm)x]L complexes synthesized by the reaction of cobalt(II) and copper(II) fumarates ML · nH2O with imidazole (Im) and 2-methylimidazole (MeIm) were determined. The thermal decomposition of the salts was analyzed, and the pyridine nitrogen atom of imidazole and the oxygen atoms of carboxyl anions were shown to participate in complexation using electronic absorption spectra and IR spectra. The composition and stability of cobalt(II) and copper(II) imidazolatesuccinate complexes in an aqueous solution were determined photometrically and spectrophotometrically, and their higher stability in comparison with monoligand complexes was demonstrated.