Synthesis and Structural and Biological Activity Studies on Some Lanthanide Chelates with O‐ and N‐Containing Ligands

Abstract

The synthesis of Ce³⁺, Th⁴⁺, and UO₂ ²⁺ complexes with six azo compounds based on 4‐methyl‐6,7‐dihydroxy‐8‐arylazo coumarin is reported. The azo compounds were expected to coordinate through O and N either in the azo or in the hydrazone form, but different physicochemical studies (elemental and thermal analysis, molar conductance, IR, magnetic susceptibility, ¹H‐NMR, and electronic absorption spectra) show that they coordinate via O, O with the coumarins acting as mono (or sometimes di‐) basic and bidentate ligands. Biological activity of some complexes has been evaluated against some filamentous microscopic fungi, yeast, and bacteria. The results are compared to those of the free ligands.

Keywords:

• Biological activity
• Ce³⁺
• Electronic spectra
• ¹H‐NMR
• IR
• 4‐Methylesculetin azo dyes
• TGA
• Th⁴⁺
• UO₂ ²⁺

Acknowledgment

The author thanks Dr. M. M. Amer, Botany Department, Faculty of Science, Benha University, Benha, Egypt, for biological screening experiments.