Complexes derived from strong field ligands. XVI. The transition metal complexes of 2-pyridinalhydrazones

Article abstract of DOI:10.1021/ic50010a020

A variety of complexes have been synthesized with methyl and phenyl substituted 2-pyridinalhydrazones. Magnetic moments, molar conductances, and spectral data have been applied to the characterization of the compounds. The properties of the cobalt(II) and nickel(II) complexes are typical of spin-free octahedral species, while the behavior of the iron(II) complexes provides evidence for an interesting steric effect. Although all the other known complexes of iron(II) with pyridinal imines and hydrazones are spin-paired, tris-(2-pyridinaldimethylhydrazone)-iron(II) iodide is paramagnetic with a magnetic moment of 5.45 Bohr Magnetons. This is explained on the assumption that the - NNR′ group of the hydrazone group is planar. The hypothesis is supported by spectral and other results. Similar steric effects limit the number of molecules of pyridinalphenylhydrazone that may enter an octahedral coordination sphere.