Thermodynamics of Mixed-Ligand Complex Formation of Mercury(II) Ethylenediaminetetraacetate with Ethylenediamine and Hexamethylenediamine in an Aqueous Solution

Formation of Mixed-Ligand Complexes of Mercury(II) with Mono- and Diamine Complexone Ligands in Aqueous Solution

“…The 1 H NMR spectra of the solutions containing HgEdta and monoamine complexone (Ida, Nta) were characterized by degeneration of the AB quadruplet into a broadened singlet, due probably to N → Hg bond labilization upon the coordination of additional high-denticity ligands by mercury(II) cations. The same situation was observed earlier upon the coordination of sulfur-containing ligands (cysteine, thiourea) [6] and aliphatic (En) [3] and heterocyclic (Dipy, Phn) [4] amines.…”

“…n n in the investigated systems, plotted with the data obtained in this work. The calculations showed that under the experimental conditions, the contribution from substitution reactions (3) to the observed pH and enthalpy values did not exceed the experimental error. Mixed-ligand species are thus the dominant ionic species in a broad range of pH.…”

“…In [2][3][4][5][6], we studied the stability of mixed-ligand complexes of Hg(II) ethylenediaminetetraacetate with different mono-and diamine ligands and amino acids. The obtained data showed that the coordination number of Hg(II) in a complex with Edta was >6, resulting in displacement of the intraspheric water molecule from HgEdta(H 2 O) 2− as an additional ligand was coordinated.…”