Azo Complexes of Cu(II), Co(II), Ni(II), Cd(II), Th(IV), and UO₂(VI) Ions. Mixed‐Ligand Complexes, Pyrolysis Products and Biological Activity

Abstract

The reactions of azo ligand, 2‐[2′‐carboxyphenylazo]‐5,5‐dimethyl‐1,3‐cyclohexane‐dione, (H₂L), with the metal ion Cd(II), Cu(II), Ni(II), Co(II), Th(IV), or UO₂(VI) in the presence of LiOH as a deprotonating agent, yielded binary mononuclear complexes. The binary Cu(II) complex reacts with the ligands 1,10‐phenanthroline or 2‐aminopyridine to form mixed‐ligand complexes. All the binary complexes of Cd(II), Cu(II), and Ni(II) have octahedral configurations, while the Co(II) complex is square‐planar. The binary complexes of Th(IV) and UO₂(VI) have distorted dodecahedral geometries. The mixed‐ligand complexes have octahedral configurations. Thermal studies on these complexes showed the possibility of obtaining new complexes pyrolytically, where the 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 complexes were found to activate the enzyme pectinlyase.

Keywords:

• Azo complexes
• Mixed‐ligand
• Pyrolysis
• Biological activity

Acknowledgment

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