Synthesis, crystal structure, hydrogen bonding and spectroscopy of Co3+, Mn3+ and Ni2+ oxalate complexes with the ligand (N,N′-bis(2-pyridylmethyl)-1,3-propanediamine)

Three new compounds are reported with the tetradentate ligand (N,N′-bis(2-Pyridylmethyl)-1,3-propanediamine) (abbreviated as pypn), two mononuclear compounds i.e. [Co(pypn)(C2O4)](ClO4) (1), [Mn(pypn)(C2O4)](ClO4) (2) and one dinuclear compound [Ni2(pypn)2(C2O4)](ClO4)2(C2H6O)1/4(H2O) (3). In the Co(III) and Mn(II) complexes the oxalate behaves as bidentate ligand, chelating the metal in the O,O′ mode, whereas in the Ni(II) compound the oxalate behaves as tetradentate ligand binding each Ni(II) ion by two oxygen atoms and bridging the two metallic centers. nthesis, X-ray crystal structure of all three compounds and their spectroscopic properties are presented in detail. The geometry around the Co3+, Mn3+, Ni2+ ions is essentially octahedrally based, while the stabilization of the crystal lattice in all cases is maintained by interesting hydrogen bond systems.