Synthesis and characterization of bis-acylhydrazone derivatives as tetradentate ligands and their dinuclear metal(II) complexes

Abstract

Two novel bis-acylhydrazone where as 1,4-diacetylbenzene bis(4-hydroxy benzoyl hydrazone) H IntroductionHydrazones are the condensation products of hydrazine derivatives with carbonyl compounds, they contain an acyclic group >C=N-N< . It is long since hydrazones and their derivatives, due to their high complexing ability, have attracted the attention of scientists. Depending on various factors (the nature of the hydrazone and the metal atom, reaction conditions, the ratio of reactants etc.) hydrazones form either mono-or polynuclear coordination compounds with metal atoms [1].Aroyl hydrazones and their metal derivatives often possess biological activity and can inhibit enzymatic reactions in the cell [2]-[4]. Edward et al. have shown that replacement of the aromatic group by other moieties in some antibiotics improves their antibiotic activity [5,6]. Apart from biological applications owing to the presence of the toxicologically important N-C=O moiety, hydrazones act as potential donors for different metal ions. These ligands contain an amide bond and are capable of undergoing keto-enol tautomerism: they can coordinate to central metal ions through nitrogen and/or oxygen [7]. Their coordination behaviour also depends upon the pH of the medium, the nature of the substituents and the metal [8].Intensive investigations of the coordination chemistry of dinuclear metal complexes with chelating ligands continue to be stimulated by interest for metallobiomolecules [9], the search for appropriate systems for binding and activating simple molecules, catalysis and magnetic interactions [10,11]. In spite of the greatest effort and success in the study of dinuclear copper(II) complexes, such complexes have still attracted much attention due to their interesting properties and the relative simplicity of their synthesis.Many studies of polyfunctional Schiff bases and monohydrazones as well as their complexes have been carried out [12,13]. Relatively few reports are available on the coordination behaviour of bis-acylhydrazone. These ligands might have interesting ligational features since they contain additional donor sites, i.e. C=O, N-H, azomethine nitrogen atom, etc. Herein, we report the synthesis and spectroscopic studies of dinuclear metal(II) polymeric complexes containing 1,4-diacetylbenzene bis(4-hydroxy benzoylhydrazone) (H 2 L 1 ) and

Synthesis, characterization, docking and antimicrobial activity studies of binuclear Co(II) and Ni(II) complexes of bis aroylhydrazone and phenanthroline

“…The magnetic moment values of complexes [Co2(HL)(dmphen)2Cl4], [Co2(HL)(phen)2Cl4] found to be 5.3 and 5.17 BM, respectively, these values are slightly higher than the theoretical values of mono nucleated cobalt complexes and lower than the expected di nucleated cobalt complexes. These magnetic moment values attribute the di nuclear nature of complexes and it may be occurred due to the weak anti ferromagnetic intra molecular coupling interaction between the two metal ions [18,21]. Whereas nickel complexes are diamagnetic in nature, it suggests the square planar geometry around nickel(II) ion [22,23].…”