Metal(II) Ion Complexes with 5‐(Pyrazin‐2‐yl)‐2,4‐dihydro‐3H‐1,2,4‐triazole‐3‐thione; Synthesis, Structural Characterization, Acid‐base, and Complexing Properties in Solution

Abstract

The study reports the synthesis of complexes Co(HL)Cl 2 (1), Ni(HL)Cl 2 (2), Cu(HL)Cl 2 (3), and Zn(HL) 3 Cl 2 (4) with the title ligand, 5-(pyrazin-2-yl)-1,2,4-triazole-5-thione (HL), and their characterization by elemental analyses, ESI-MS (m/z), FT-IR and UV/Vis spectroscopy, as well as EPR in the case of the Cu II complex. The comparative analysis of IR spectra of the metal ion complexes with HL and HL alone indicated that the metal ions in 1, 2, and 3 are chelated by two nitrogen atoms, N(4) of pyrazine and N(5) of triazole in the thiol tautomeric form, whereas the Zn II ion in 4 is coordinated