Spectrothermal studies of 1,10-phenanthroline complexes of Co(II), Ni(II), Cu(II) and Cd(II) orotates

The 1,10-phenanthroline (phen) complexes of Co(II), Ni(II), Cu(II) and Cd(II) orotates were synthesized and characterized by elemental analysis, magnetic susceptibility, spectral methods (UV-vis and FTIR) and thermal analysis techniques (TG, DTG and DTA). The Co(II), Ni(II), Cu(II) and Cd(II) ions in diaquabis(1,10-phenanthroline)metal(II) diorotate octahedral complexes [M(H2O)(2)(phen)(2)](H(2)Or)(2)center dot nH(2)O (M=Co(II), n=2.25; Ni(II), n=3; Cu(II) and Cd(II), n=2) are coordinated by two aqua ligands and two moles of phen molecules as chelating ligands through their two nitrogen atoms. The monoanionic orotate behaves as a counter ion in the complexes. On the basis of the first DTG(max), the thermal stability of the hydrated complexes follows the order: Cd(II), 68 degrees C < Ni(II), 74 degrees C < Cu(II), 135 degrees C < Co(II), 166 degrees C in static air atmosphere.