Cobalt(II), nickel(II), and copper(II) complexes with some 5-aminopyrazole-containing azo compounds

The Co(II), Ni(II), and Cu(II) chelates with four heterocyclic azo compound s have been prepared and characterized. Characterization of the solid so ob tained was accomplished by elemental and thermogravimetric analysis, electr onic and IR spectra, as well as conductivity measurements. The dyes are cha racterized by high tendency towards complex formation with neutral molecule s coordinated to the metal ion as bidentate ligands. The different bands ob served in the visible spectra of methanolic solutions of the complexes have been assigned to the possible electronic transition type (L-M CT and d-d).