Preparation, spectroscopic study of Schiff base derived from dopamine and metal Ni(II), Pd(II), and Pt(IV) complexes, and activity determination as antioxidants

Abstract

A new Schiff base (HL2) ligand (4‐{2‐[(2‐hydroxy‐benzylidene)‐amino]‐ethyl}‐benzene‐1,2‐diol) has been synthesized by condensing of 4‐(2‐amino‐ethyl)‐benzene‐1,2‐diol and 2‐hydroxy‐benzaldehyde. In turn, its transition metal complexes were prepared, having the following general formulas: Ni(L2)2, Pd(L2)2, and Pt(L2)22Cl. The prepared ligand and its metal complexes Ni(II), Pd(II), and Pt(IV) have been characterized by Fourier transform infrared (FTIR) spectra, proton nuclear magnetic resonance (1H‐NMR) elemental analysis, metal content, chloride content, molar conductance, ultraviolet–visible (UV–Vis) spectra, magnetic susceptibility, mass spectrometry (MS) spectra, and thermogravimetric analysis (TGA). The consequences proposed that Schiff base acts like a bidentate ligand for all the prepared complexes. The antioxidant performance of as‐prepared compounds was inspected using the DPPH radical scavenging method. The compounds showed antioxidant activities of scavenging free radicals.

Synthesis and Characterization of Some Metals Complexes with New Acidicazo Ligand 4-[(2-Amino-4-Phenylazo)-Methyl]-Cyclohexane Carboxylic Acid

“…The Pd complex decomposes in two phases with an intact residue, but only in two stages. This matches both the calculated values and the suggested formula [31][32][33][34][35][36][37].…”

Synthesis, Characterization, and Thermal Analysis of a New Acidicazo Ligand's Metal Complexes

“…The TG and DSC results of heat breakdown of the ligand and related metal complexes are shown in Figs ( 5 and 6), Table 4 contains information on the thermal degradation process. The prepared compounds showed a decomposition in the thermogravimetric decomposition curve, where the ligand thermal stability was poor at 50°C, similar to the low stability complexes in the range of (40, 38, 65, 65, and 200 °C) for Co(II), Cr(III), Mn(II), Rh(III), and Ru(III), respectively, indicating the presence of water molecules only in the Co(II) complex, whether water hydrate or aqua, 37,38 Table 4 shows the findings of the study.Co(II), Cr(III), and Ru(III) decompose in two stages with an unbroken residue, while the ligand decomposes in three stages with an unbroken residue. 39,40 The Mn(II) and Rh(III) complexes disintegrate in one stage with an unbroken residue.…”

Untitled

“…When compared with the ligand spectrum, all complex spectra show the removal of the (O -H) phenolic and (NH2) bands. This proves that the ligand was coordinated with the metal ion through the nitrogen and oxygen atoms [30] and new bands are appeared that belongs to (M-N) at (561, 533, and 549) cm -1 for the complexes (Ni, Pd, and Pt), respectively, (M-O) at (499, 480, and 493) cm -1 for the complexes (Ni, Pd, and Pt), respectively which supports coordination occurrence through the nitrogen and oxygen atoms [31,32]. All complexes showed new bands to correlate to coordinated water molecules in the complexes [33].…”