Synthesis and spectroscopic characterization of bivalent metal complexes of 2,6-diacetylpyridine bis(octanoylhydrazone). X-ray crystal structure of a nickel(II) complex

A new hydrazonic ligand, 2,6-diacetylpyridine bis(octanoylhydrazone) (H(2)dapo), has been prepared and examined as chelating agent towards iron(II), cobalt(II), nickel(II) and palladium(II) ions. All the compounds have been characterized by IR and H-1 and C-13 NMR spectroscopies. The X-ray diffraction analysis carried out on [Ni(H(2)dapo)(OH2)(2)]Cl-2 showed a pentagonal bipyramidal stereochemistry which can be also assumed for the Fe and Co chloro complexes, while for Ni(dapo) and Pd(dapo) the spectroscopic investigation suggests a square planar coordination and a different configuration (E and Z) for the two hydrazonic chains.