Complex‐Formation Ability of Salicylaldehyde Thiosemicarbazone towards Zn^II, Cu^II, Fe^II, Fe^III and Ga^III Ions

Abstract

The stoichiometry and stability of copper(II), zinc(II), iron(II)/ (III) and gallium(III) complexes of salicylaldehyde thiosemicarbazone (STSC, H 2 L) have been determined by pH potentiometry, UV/Vis spectrophotometry, and 1 H 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 Fe II , Fe III and Ga III , whereas Cu II and Zn II ions only form complexes with a 1:1 metal/ligand ratio. The coordination mode in the complex [a]

Vanadium(IV/V) complexes of Triapine and related thiosemicarbazones: Synthesis, solution equilibrium and bioactivity

“…The acid-base properties of STSC have already been studied in detail in our previous work [25], and the pK a values determined here are in good agreement with the published data ( considerably higher compared to those of the α(N)-pyridyl TSCs ( Table 1). …”

“…As expected, the methyl groups on the terminal nitrogen of the α-pyridyl TSCs increase the logD 7.4 value compared to that of the reference compound Triapine [25].…”

“…This can probably be explained by the fact that α(N)-pyridyl TSCs were found to be unambiguously more efficient chelators for Fe(II) than STSC over a wide pH range [25]. This indicates that in case of STSC the redox cycling of the intracellularly formed iron complexes, which is assumed to be crucial for the activity of thiosemicarbazones, is hampered [6].…”

Design, synthesis and biological evaluation of thiosemicarbazones, hydrazinobenzothiazoles and arylhydrazones as anticancer agents with a potential to overcome multidrug resistance

“…Therefore the salicylidene compounds might prefer harder metals than the picolinylidene derivatives [110]. A study comparing the stability of several metal complexes formed by the N4 unsubstituted salicyl-and pyridyl-carbaldehyde TSCs supports this general trend [111]. The different chelators might not only influence the stability of complexes formed with diverse metal ions, but also their redox properties.…”

Effects of Terminal Dimethylation and Metal Coordination of Proline-2-formylpyridine Thiosemicarbazone Hybrids on Lipophilicity, Antiproliferative Activity, and hR2 RNR Inhibition

“…Low aqueous solubility of TSCs is a common feature, that explains the limited number of studies in aqueous solution reported so far. 43,44,45,46,47 From the other side aqueous solubility has influence on a compound's bioavailability through solubility-limited absorption, but is important for validation of in vitro antiproliferative activity assays. 48 We reported recently on the first proline-TSC hybrids (L-and D-Pro-FTSC) and their copper(II) complexes.…”