Construction of a new versatile hydrazonic ligand and its chemical and structural behaviour towards metal ions

Abstract

The synthesis of a new hydrazonic ligand, 2,6-diacetylpyridine bis[2-(semicarbazono) propionylhydrazone](H₄L), is reported together with the synthesis, X-ray structure analysis and the IR spectroscopic characterisation of the complexes [{Ni₂(H₂L)(OH₂)Cl}₂Cl₂]·2dmf·5H₂O 1(dmf = dimethylformamide), [Co(H₄L)(OH₂)₂][NO₃]₂·2H₂O 2 and [Zn(H₃L′)(OH₂)₂][ClO₄]₂·1.5H₂O 3[H₃L′= 2,6-diacetylpyridine semicarbazone 2-(semicarbazono) propionylhydrazone]. The interest of these structures pertains mainly to the cations. In 1 a tetranuclear complex is present with two nonequivalent nickel atoms, both of which exhibit distorted-octahedral co-ordination, and with the hydrazone acting as enneadentate donor. The structures of 2 and 3 consist of monomeric units in which the metal atom has a pentagonal-bipyramidal environment with two axial H₂O molecules and the hydrazone ligand forming the basal plane.