Spectrothermal Studies on Co(II), Ni(II), Cu(II) and Zn(II) Salicylato (1,10-Phenanthroline) Complexes

Abstract

The cobalt, nickel, copper and zinc atoms in bis(1, 10-phenanthroline) bis(salicylato-O)metal(II) monomeric octahedral complexes [M(Hsal) <inf>2</inf>(phen)<inf>2</inf>]nH<inf>2</inf>O, (M: Co(II), n=1; Cu(II), n=1.5 and Ni(II), Zn(II), n=2) are coordinated by the salicylato monoanion (Hsal) through the carboxyl oxygen in a monodentate fashion and by the 1,10-phenanthroline (phen) molecule through the two amine nitrogen atoms in a bidentate chelating manner. On the basis of the DTG<inf>max</inf>, the thermal stability of the hydrated complexes follows order: Ni(II) (149°C)>Co(II) (134°C)>Zn(II) (132°C)>Cu(II) (68°C) in static air atmosphere. In the second stage, the pyrolysis of the anhydrous complexes takes place. The third stage of decomposition is associated with a strong exothermic oxidation process (DTA curves: 410, 453, 500 and 450°C for the Co(II), Ni(II), Cu(II) and Zn(II) complexes, respectively). The final decomposition products, namely CoO, NiO, CuO and ZnO, were identified by IR spectroscopy.