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

Abstract

Anthraniloyl hydrazide (AH) contains two −NH 2 groups, one of them is attached to the aromatic ring and the other is the hydrazinic, −NH 2 . 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 −NH 2 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.

Synthesis, characterization and antimicrobial activity of pentagonal-bipyramidal isothiocyanato Co(II) and Ni(II) complexes with 2,6-diacetylpyridine bis(trimethylammoniumacetohydrazone)

“…Lanthanide complexes with coordination numbers larger than seven were reported [12][13][14][15][16][17] with one dihydrazone ligand and the remaining coordination sites occupied with monodentate or bidentate ligands [12][13][14][15][16][17]; however, in isostructural complexes of Pr(III) and Sm(III) two ligands are pentadentate N 3 O 2 coordinated to the metal ion [14]. Mono-and binuclear octahedral complexes of Ni(II) with 2,6-diacetylpyridine dihydrazones were reported [18][19][20]. In the mononuclear Ni(II) complex, two monodeprotonated dihydrazone ligands are NNO tridentate, coordinated through pyridine nitrogen, azomethine nitrogen and carbonyl oxygen [18].…”

“…In the mononuclear Ni(II) complex, two monodeprotonated dihydrazone ligands are NNO tridentate, coordinated through pyridine nitrogen, azomethine nitrogen and carbonyl oxygen [18]. In binuclear Ni(II) complexes, the dihydrazone ligands are coordinated to one Ni(II) center through protonated amide oxygen and azomethine nitrogen, while the pyridine nitrogen is a bridge between two nickel centers [19,20]. Dinuclear complexes of Zn(II) with octahedral [11] and square-pyramidal geometry [21] around metal centers were reported.…”

Interplay of thermochemistry and Structural Chemistry, the journal (volume 18, 2007) and the discipline

“…The next article, by Naskar et al [103], describes synthesis, characterization, and crystal structure of [Ni(dap(A) 2 )] 2 (dap(AH) 2 = 2,6-diacetylpyridine bis(anthraniloyl hydrazone)). This molecule possesses a double helical chain in the solid state due to hydrogen bonding.…”

Synthesis, characterization, DFT calculations and antimicrobial activity of pentagonal-bipyramidal Zn(II) and Cd(II) complexes with 2,6-diacetylpyridine-bis(trimethylammoniumacetohydrazone)

“…Coordination of N 3 O 2 donors allows formation of pentagonal-bipyramidal (PBPY- 7) complexes with resonance stabilized nearly planar system in equatorial plane, consisting of four five-membered chelate rings and monodentate ligands in the apical positions [1,2]. Pentagonalbipyramidal (PBPY-7) geometry is not exclusive for complexes with 2,6-diacetylpyridine acylhydrazones and the extent of its deformation depends on conformational flexibility of ligand molecule, d n configuration of the metal ion and reaction conditions [2][3][4][5][6]. Coordination of 2,6-diacetylpyridine acylhydrazone ligands to Zn(II) may result in formation of both mono [7] and binuclear complexes [8,9].…”