Synthesis and Characterization of New Transition and Actinide Metal Complexes of a Hydrazone Ligand. Mixed‐Ligand Complexes, Pyrolysis Products, and Biological Activity

Abstract

The chelating properties the hydrazone ligand 2‐carboxyphenylhydrazo‐ethylcyanoacetate (H₂L) have been studied. A new series of binary mononuclear complexes were prepared from the reaction of the hydrazone ligand (H₂L) with the metal ions, Cd(II), Cu(II), Ni(II), Co(II), Th(IV), and UO₂(VI), in the presence of LiOH as a deprotonating agent. The binary Cu(II) complex of H₂L was reacted with the ligands 1,10‐phenanthroline or 2‐aminopyridine to form mixed‐ligand complexes. The binary complexes of Cu(II) and Ni(II) are suggested to have octahedral configurations. The Cd(II) and Co(II) complexes are suggested to have tetrahedral and/or square‐planar geometries, respectively. The Th(IV) and UO₂(VI) complexes are suggested to have octahedral and dodecahedral geometries, respectively. The mixed‐ligand complexes have octahedral configurations. Also, new complexes were obtained pyrolytically as the previous complexes decompose through several isolable as well as non‐isolable intermediates during heating. The structures of all complexes and the corresponding thermal products were elucidated by elemental analyses, conductance, IR and electronic absorption spectra, magnetic moments, ¹H NMR and TG–DSC measurements, as well as by mass spectroscopy. The ligand and some of the metal complexes were found to activate the enzyme pectinlyase.

Keywords:

• Hydrazone
• Metal complexes
• Thermal
• Biological activity

Acknowledgment

The authors whish to express their thanks to Dr. Usama Fahmy Ali Hamed, Biology Department, Faculty of Education, Ain Shams University for the biological testing.