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Metal(II) Ion Complexes with 5‐(Pyrazin‐2‐yl)‐2,4‐dihydro‐3 H ‐1,2,4‐triazole‐3‐thione; Synthesis, Structural Characterization, Acid‐base, and Complexing Properties in Solution
Author(s) -
Kufelnicki Aleksander,
JaciubekRosińska Jolanta,
Sobiesiak Marta,
Paneth Agata,
Jezierska Julia,
Budzisz Elzbieta
Publication year - 2017
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/zaac.201700102
Subject(s) - chemistry , protonation , tautomer , electron paramagnetic resonance , metal , chelation , infrared spectroscopy , metal ions in aqueous solution , ligand (biochemistry) , inorganic chemistry , crystallography , 1,2,4 triazole , copper , ion , medicinal chemistry , organic chemistry , biochemistry , physics , receptor , nuclear magnetic resonance
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 by the non‐protonated N(2) nitrogen atom of triazole in the thione form. pH potentiometry and UV/Vis spectroscopy were used to examine Co II , Ni II , and Zn II complexes in 10/90 (v/v) DMSO/water solution, whereas the Cu II complex was examined in 40/60 (v/v) DMSO/water solution. Monodeprotonation of the thione triazole in solution enables the formation of the L: M = 1:1 species with Co II , Ni II and Zn II , the 2:1 species with Co II and Zn II , and the 3:1 species with Zn II . A distorted tetrahedral arrangement of the Cu II complex was suggested on the basis of EPR and Vis/NIR spectra.