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Updated: Nov 30, 2025

Synthesis and Performance Evaluations of ZnCoS/ZnCdS with Twin Crystal Structure for Multifunctional Redox Photocatalysis in Energy Applications
Published on: July 25, 2025
Synthesis, Characterization and Assessment of the Antioxidant Activity of Cu(II), Zn(II) and Cd(II) Complexes Derived
Aurel Tăbăcaru1, Rais Ahmad Khan2, Giulio Lupidi3
1Department of Chemistry, Physics and Environment, Faculty of Sciences and Environment, "Dunarea de Jos" University of Galati, 111 Domneasca Street, 800201 Galati, Romania.
Abstract:
Seeking to enrich the yet less explored field of scorpionate complexes bearing antioxidant properties, we, here, report on the synthesis, characterization and assessment of the antioxidant activity of new complexes derived from three scorpionate ligands. The interaction between the scorpionate ligands thallium(I) hydrotris(5-methyl-indazolyl)borate (TlTp4Bo,5Me), thallium(I) hydrotris(4,5-dihydro-2H-benzo[g]indazolyl)borate (TlTpa) and potassium hydrotris(3-tert-butyl- pyrazolyl)borate (KTpBu), and metal(II) chlorides, in dichloromethane at room temperature, produced a new family of complexes having the stoichiometric formula [M(Tp4Bo,5Me)2] (M = Cu, 1; Zn, 4; Cd, 7), [M(Tpa)2] (M = Cu, 2; Zn, 5; Cd, 8), [Cu(HpzBu)3Cl2] (3), [Zn(TptBu)Cl] (6) and [Cd(BpBu)(HpzBu)Cl] (9). The obtained metal complexes were characterized by Fourier transform infrared spectroscopy, proton nuclear magnetic resonance and elemental analysis, highlighting the total and partial hydrolysis of the scorpionate ligand TpBu during the synthesis of the Cu(II) complex 3 and the Cd(II) complex 9, respectively. An assessment of the antioxidant activity of the obtained metal complexes was performed through both enzymatic and non-enzymatic assays against 1,1-diphenyl-2-picryl- hydrazyl (DPPH), 2,2'-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS+), hydroxyl (HO·), nitric oxide (NO), superoxide (O2-) and peroxide (OOH) radicals. In particular, the complex [Cu(Tpa)2]⋅0.5H2O (2) exhibited significant antioxidant activity, as good and specific activity against superoxide (O2-·), (IC50 values equal to 5.6 ± 0.2 μM) and might be identified as auspicious SOD-mimics (SOD = superoxide dismutase).
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