Synthesis, Characterization, and Antioxidant Activity of Pt (II) and Pd (II) Dithiocarbamate Complexes Derived from 4-Methyl-2-phenylpiperazine and 4-Phenylpiperazine with and without 1,2-Bis(diphenylphosphino)ethane
1 Department of Chemistry, College of Science, University of Kirkuk, Kirkuk, Iraq.
2 Department of Chemistry, College of Education for Science, University of Kirkuk, Kirkuk, Iraq.
3 Department of Chemistry, College of Science, University of Sulaymaniyah, Sulaymaniyah, Kurdistan Region, Iraq.
Qusay Kh. Abdullah; ORCID: 0009-0001-0014-6566.
Hasan A. Mohammed; ORCID: 0000-0002-1179-7604.
Diary I. Tofiq; ORCID: 0000-0002-0728-9519.
Research Article
World Journal of Chemical and Pharmaceutical Sciences, 2026, 09(01), 013–025.
Article DOI: 10.53346/wjcps.2026.9.1.0022
Publication history:
Received on 28 May 2026; revised on 04 July 2026; accepted on 06 July 2026
Abstract:
Synthesis of all the ligands, dithiocarbamate sodium 4-methyl-2-phenylpiperazine-1-carbodithioate (L1) and sodium 4-phenylpiperazine-1-carbodithioate (L2) through etherification reaction between their corresponding secondary amines with carbon disulfide in ethanol containing NaOH as precursor reagent. A series of ten metal complexes was subsequently prepared: homoleptic bis-dithiocarbamate complexes [Pt(L1)2], [Pd(L1)2], [Pt(L2)2], [Pd(L2)2], and mixed-ligand phosphine complexes [Pt(L1)2(dppe)], [Pd(L1)2(dppe)], [Pt(L2)2(dppe)], and [Pd(L2)2(dppe)], where dppe = 1,2-bis(diphenylphosphino)ethane. The synthesized compounds were characterized by elemental analysis (CHNS), FT-IR, UV-Vis, 1H-NMR, 13C-NMR (for ligands) and 31P-NMR (for phosphine complexes) spectroscopies in combination with molar conductivity measurements. FT-IR spectra provide evidence for coordination through the dithiocarbamate sulfur atoms, indicated by shifts in ν(C=S) and ν(C–N) bands as well as the appearance of ν(M–S) in the low-frequency region. The Pt(II) phosphine complexes had three 31P-NMR signals, in accordance with trans-to-S and trans-to-P inequivalent environments whereas the Pd(II) analogues showed a single phosphorus signal. The molar conductivity data confirmed the neutral complex as non-electrolytic. The antioxidant activity determined by the DPPH radical-scavenging assay showed that L1 and [Pt(L2)2(dppe)] have excellent antioxidant activities with IC50 = 40 µg/mL comparable to the standard ascorbic acid (IC50 =26.67 µg/mL).
Keywords:
Dithiocarbamate; Platinum(II); Palladium(II); Phosphine; Dppe; Antioxidant; DPPH; Piperazine; Square Planar; 31P-NMR.
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