Synthesis, characterization and extraction studies of some metal (II) complexes containing (hydrazoneoxime and bis-acylhydrazone) moieties

In this study, diacetylmonoximebenzoylhydrazone (L1H2) and 1,4-diacetylbenzene bis(benzoyl hydrazone) (L2H2) were synthesized by the condensation of benzohydrazide with diacetyl monoxime and 1,4-diacetylbenzene, respectively. Complexes of these ligands with Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) inos were prepared with a metal:ligand ratio of 1:2 for L1H2 ligand, and 1:1 for L2H2 ligand. The ligands and their complexes were elucidated on the basis of elemental analyses CHN, AAS, FT-IR, 1H- and 13C NMR spectra, UV–vis spectra and magnetic susceptibility measurements. Results show the L1H2 ligand act as monoanionic O,N,N-tridentate and coordination takes place in the enol form through the oxime nitrogen, the imine nitrogen and the enolate oxygen atoms with a N4O2 donor environment, while the L2H2 ligand act as a dianionic O,N,N,O-tetradentate and coordination takes place in the enol form through the enolate oxygen and the azomethine nitrogen atoms with a N2O2 donor environment. These results are consistent with the formation of mononuclear metal (II) complexes [M(L1H)2], and binuclear polymeric metal (II) complexes [{M2(L2)}n]. The extraction ability of both ligands were examined in chloroform by the liquid–liquid extraction of selected transition metal [Co2+, Ni2+, Cu2+, Zn2+ and Pb2+] cations. The effects of pH and contact time on the percentage extraction of metal (II) ions were studied under the optimum extraction conditions. The (L1H2) ligand shows strong binding ability toward copper(II) and lead(II) ions, while the (L2H2) ligand shows strong binding ability toward nickel(II) and zinc(II) ions.

Graphical abstractSynthesis and characterization of the mononuclear metal (II) complexes [M(L1H)2] and polymeric dinuclear metal (II) complexes [{M2(L2)2}n]; n = 0, 1, 2…; M = Co(II), Ni(II), Cu(II), Zn(II), and Cd(II) derived from synthesized ligands diacetylmonoximebenzoylhydrazone (L1H2) and 1,4-diacetylbenzene-bis(benzoylhydrazone) (L2H2) respectively. The 1H NMR, 13C NMR, elemental analysis(CHN), FT-IR infrared spectra, Magnetic susceptibility measurements and UV–vis. electronic absorption spectra of the (L1H2) and (L2H2) ligands and their metal (II) complexes were reported and investigated.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► We synthesis (hydrazoneoxime L1H2 and bis-acylhydrazone L1H2) ligands and their complexes. ► These compounds characterized by CHN, AAS, IR, 1H,13C NMR, UV–vis spectra and μeff. ► The L1H2 act as monoanionic O,N,N-tridentate, but the L2H2 act as dianionic O,N,N,O-tetradentate. ► We examine the extraction ability of ligands in chloroform by the liquid–liquid extraction. ► Strong affinity of ligands towards several metal (II) ions have been studied in aqueous phase.