Synthesis and Characterization of Bis-acylhydrazone Derivatives as Tetradentate Ligands and Their Dinuclear Metal(II) Complexes

Abstract

AbstractTwo new bis-acylhydrazone where as 1,4-diacetylbenzene bis(4-hydroxy benzoyl-hydrazone) (L1H2) and 1,4-diacetylbenzene bis(4-nitrobenzoylhydrazone) (L2H2) ligands bearing two hydrazone side groups and their metal(II) complexes have been synthesized and characterized by 1H-NMR,13C-NMR, elemental analysis, FT-IR spectra, magnetic susceptibility measurements and UV-vis electronic absorption spectra. The (L1H2, L2H2) ligands were synthesized by reacting 4-hydroxybenzohydrazide and 4-nitrobenzohydrazide with 1,4-diacetylbenzene, respectively. The ligands (L1H2, L2H2) react with anhydrous metal(II) chlorides to form polymeric dinuclear metal(II) complexes with general formula [{M2(Lx)2}n] with a metal to ligand ratio of 1:1 when [x = 1, 2 ; M= Co(II), Ni(II), Cu(II), Zn(II), Cd(II)]. In the complexes, the ligands act as dianionic tetradentate and coordination takes place in the enol tautomeric form with the enolic oxygen and azomethine nitrogen atoms while the phenolic hydroxyl and nitro groups of dihyrazone moiety do not participate in coordination.