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.