A study of some metal complexes of the polydentate ligand 1,4-DI(2'-Pyridyl) aminophthalazine

Abstract

Coordination compounds of the ligand 1,4-di(2'-pyridyl)-aminophthalazine (PAP) and various nickel(II) and zinc(II) salts are studied. In the case of the nickel(II) complexes, infrared and electronic spectra, and elemental analyses indicate the compounds formed are binuclear and dimeric, containing nickel in a pseudo-octahedral environment; four of the coordination sites are occupied by ligand nitrogen atoms. In the nickel halide complexes the remaining coordination sites are occupied by water or, in some cases, coordinated halogen atoms, which are replaced by water in aqueous solution. Two complexes are formed with nickel nitrate, both of which contain coordinated nitrate groups, and one of them contains a bridging hydroxy group. In the coordination compounds of PAP with nickel perchlorate and tetrafluoroborate the metal atoms have coordinated water and are joined by a bridging hydroxy group. Magnetic susceptibility studies indicate antiferromagnetic exchange between the nickel atoms in the hydroxy bridged species. -- When reacted with halides or pseudohalides of zinc, PAP acts in either a bidentate or tetradentate manner, depending on the anion present. All of the PAP-zinc complexes contain coordinated anions.