Synthesis, characterization, and crystal structure of [Ni(dap(A)2)]2 (dap(AH)2:: 2,6-diacetylpyridine bis(anthraniloyl hydrazone)) -: a molecule possessing an infinite double helical chain in the solid state

Anthraniloyl hydrazide (AH) contains two - NH2 groups, one of them is attached to the aromatic ring and the other is the hydrazinic, -NH2. It is found that only the later reacts with the carbonyl compounds to form Schiff bases, while the former remains inert. The reasons behind this difference in reactivity are analyzed on the basis of semi-empirical calculations, which show that the lone pair of the ring -NH2 is considerably delocalized over the ring, resulting in an accumulation of a positive charge on this particular nitrogen. Ni(II) complex of 2,6-diacetylpyridine bis(anthraniloyl hydrazone) has been prepared and characterized by various physico-chemical methods. The structure of the complex was determined by X-ray crystallography. It was found that in the solid state, the compound exist as a dimer, and two coordinated ligand moieties form a double helix around the two metal ions. H-bonding then results in extension of double helix to an infinite chain.