Synthesis and spectral investigations of manganese(II), cobalt(II), nickel(II), copper(II) and zinc(II) complexes of new polydentate ligands containing a 1,8-naphthyridine moiety.

2-(o-Hydroxyphenyl)-1,8-naphthyridine (HN), 2-(4-hydroxy-6-methylpyran-2-one-3-yl)-1,8-naphthyridine (HMPN) and 2-(benzimidazol-2-yl)-1,8-naphthyridine(BN) react with acetates of Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) to yield metal ion complexes of definite composition. These compounds were characterized by elemental analyses, molar conductivity, magnetic susceptibility measurements, thermal studies, IR, UV-visible, NMR and mass spectral investigations. The complexes are found to have the formulae [M(HN)2(H2O)2], [M(HMPN)2(H2O)2] and [M(BN)2(OAc)2], respectively.