Complex-Formation Ability of Salicylaldehyde Thiosemicarbazone towards ZnII, CuII, FeII, FeIII and GaIII Ions

Author(s)
Eva Anna Enyedy, Eva Zsigo, Nóra Veronika Nagy, Christian Kowol, Alexander Roller, Bernhard Keppler, Tamas Kiss
Abstract

The stoichiometry and stability of copper(II), zinc(II), iron(II)/(III) and gallium(III) complexes of salicylaldehyde thiosemicarbazone (STSC, H2L) have been determined by pH potentiometry, UV/Vis spectrophotometry, and 1H NMR and EPR spectroscopy in aqueous solution (with 30?% DMSO), together with the characterization of the proton dissociation processes. Mono- and bis-ligand complexes in different protonation states were identified for FeII, FeIII and GaIII, whereas CuII and ZnII ions only form complexes with a 1:1 metal/ligand ratio. The coordination mode in the complex [Zn2(HL)(L)(OAc)EtOH] was confirmed by X-ray diffraction. The metal-binding ability of STSC at physiological pH is in the following order: GaIII <ZnII <FeII <FeIII <CuII. GaIIISTSC complexes show unambiguously higher stability, whereas FeIISTSC species show significantly lower stability relative to the corresponding a(N)-pyridyl thiosemicarbazones like 2-formylpyridine thiosemicarbazone or Triapine. Furthermore, the fluorescence properties of the ligand were investigated in aqueous solution, and their changes caused by complexation with GaIII and ZnII were studied.

Organisation(s)
Department of Inorganic Chemistry
External organisation(s)
University of Szeged, Hungarian Academy of Sciences
Journal
European Journal of Inorganic Chemistry
Volume
25
Pages
4036-4047
No. of pages
12
ISSN
1434-1948
DOI
https://doi.org/10.1002/ejic.201200360
Publication date
2012
Peer reviewed
Yes
Austrian Fields of Science 2012
104003 Inorganic chemistry
Portal url
https://ucrisportal.univie.ac.at/en/publications/5a9d23d1-6176-4d86-828d-e48a989f7334