Synthesis, spectral and thermal studies of Co(II), Ni(II) and Cu(II) complexes...

The electronic absorption spectra of 1-(4,6-dimethyl-pyrimidin-2-ylazo)-naphthalen-2-ol is studied in organic solvents of different polarity as well as in buffer solutions of varying pH values at different temperatures and different ratios of methanol. The probable structure of the azodye has been assigned on the basis of spectral studies (IR and (1)H NMR). The effect of Co(II), Ni(II) and Cu(II) ions on the emission spectrum of the free azodye is also assigned. The stoichiometry of the metal complexes is determined spectrophotometrically and conductometrically. Novel complexes of Co(II), Ni(II) and Cu(II) with the pyrimidine azodye have been synthesized and characterized on the basis of elemental analyses, molar conductance, magnetic susceptibility measurements, IR, electronic as well as ESR spectral studies The thermal decomposition of the metal complexes is studied by TGA and DTA techniques. The kinetic parameters like activation energy, pre-exponential factor and entropy of activation are estimated.