PREPARATION AND CHARACTERIZATION OF 2,2'-DIPYRIDYLAMINE, 2,2'-DIPYRIDYLKETONE AND 2,2'-DITHIODIPYRIDINE COMPLEXES OF CU(II), ZN(II), NI(II) AND U(VI) METAL-IONS

The neutral ligand (L) [where L = 2,2'-dipyridylamine (dpa), 2,2'-dipyridylketone (dpk) and 2,2'-dithiodipyridine (dtdp))] acts as bidentate electron donor to the metal. A methanolic solution of the metal salt MX2.nH2O [where M = Cu(II), Zn(II), Ni(II) and UO2(VI) and X = Cl, Br] reacts with the ligand (L) in (1:1) mole ratio to give complex of the type [ML X2] in association with or without the solvent molecule. However the salt Cu(II) when treated with (dpa) in (1:2) it yields the complex [Cu(dpa)2]X2 and with the ligand (dtdp) it yields only one type of the complex [Cu(dtdp)X2] even when a large excess of the ligand is used. All the complexes were characterized by their infrared spectra and elemental analyses. On the basis of infrared spectra it has been suggested that the ligands coordinate to the metal through the pyridine-N atoms. However the ligand (dpk) showed a low nuC = O stretching frequency indicating a direct interaction between the metal and the keto group of the ligand.