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Updated: Jul 6, 2026

Thermochemical Studies of Ni(II) and Zn(II) Ternary Complexes Using Ion Mobility-Mass Spectrometry
Published on: June 8, 2022
Resolution of carboxylate protonation microequilibria of NTA, EDTA and related complexones
Zoltán Szakács1, Szabolcs Béni, Béla Noszál
1Laboratory for Speciation, Drug and Trace Analysis, Institute of Chemistry, Eötvös Loránd University, Pázmány Péter sétány 1/a, H-1117 Budapest, Hungary.
Abstract:
Potentiometric and NMR-pH titrations were carried out on four classical complexones to elucidate their overall and site-specific basicities. NMR-pH profiles and Bjerrum's functions were adjusted to compound-specific symmetries and appropriate evaluation methods were developed. Symmetry-modulated relationships between the macro- and microconstants were deduced and self-consistent sets of microconstants were determined. The inherent basicity of carboxylates surrounded by adjacent, intramolecular ammonium and carboxylate sites have been found to be in the range of 1.83-2.02logk units, which are reduced by 0.05-0.12logk units upon a nearby carboxylate protonation.
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