Preparation and spectroscopic investigation of chelates of divalent transition metal ions with 8-(arylazo)chromones

Metal chelates of the divalent transition metal ions Mn(II), Fe(II), Co(II) , Ni(II), Cu(II), Zn(II) and Pd(II) with 8-(arylazo)chromones have been pre pared and characterized by elemental analyses, IR and electronic spectra, t hermogravimetric analyses, magnetic and conductance measurements. The obtai ned data suggest the formation of 1:1 and 2:1 (M:Ligand) chelates with the general formula [MHk-1LXm(H2O)(n)].yH(2)O or [M2Hk-2LXm(H2O)(n)].yH(2)O whe re X = OH or Cl, m = 1 or 2, n = 1-3 or 6, y = 1-3 or 5, k = 2-4, M is a di valent transition metal ion and HkL represents the 8-(arylazo)-chromones. T he study revealed that the ligands behave as monobasic bidentates in the ca se of 1:1 (M:Ligand) chelates and as dibasic tetradentates in the case of t he 2:1 (M:Ligand) chelates. Electronic spectra and magnetic measurements in dicate that the metal chelates have square-planar, tetrahedral or octahedra l geometries. The TG analyses indicate the presence of hydrated and coordin ated water molecules. A nonelectrolytic nature was assigned based on molar conductance measurements.