Synthesis and Characterization of Schiff Base from 4,4-Diaminodiphenyl Ether and Vanillin and its Interaction with Cu2+ Metal Ion

Abstract

The Schiff base has synthesized from the reaction between 4,4-diaminodiphenyl ether and vanillin. The resulting Schiff base acts as a ligand and interacts with Cu²⁺ metal ions to form a complex compound. The Schiff base was analyzed using UV-visible and FT-IR spectroscopy, as well as X-ray diffraction (XRD). The stability of the Schiff base under different pH conditions was investigated, along with the interference effects of Cd²⁺ and Zn²⁺ ions on the formation of Schiff base complexes with Cu²⁺. The formation of a yellow solid crystal indicated the successful synthesis of the Schiff base. The appearance of maximum absorption at 250 nm on the UV-Vis spectra signifies the electronic transition from π to π*. Absorption spectra at 1600 cm^-1 indicate the presence of an azomethine group. The diffraction pattern showed a sharp peak at an angle of 2θ= 19.301°, 51.04° for the Schiff base 4,4-diamino diphenyl ether-vanillin. Schiff base compounds exhibit the highest stability at pH 5, where the C=N double bond formed is more stable than other pH. Schiff base ligands form complexes with Cu²⁺ metal ions, characterized by absorption in the charge transfer region (LMCT) at λ 400 nm and the d-d transition at λ 630 nm. The presence of Cd²⁺ and Zn²⁺ metal ions shifting absorption of the Schiff Base-Cu²⁺ ligand complex towards shorter wavelengths (hypsochromic effect)