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 (HL 2 ) 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(L 2 ) 2 , Pd(L 2 ) 2 , and Pt(L 2 ) 2 2Cl. 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 ( 1 H‐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.