%0 Journal Article
%T [15]aneN4S: Synthesis, Thermodynamic Studies and Potential Applications in Chelation Therapy
%A Nuno Torres
%A Sandrina Gon£¿alves
%A Ana S. Fernandes
%A J. Franco Machado
%A Maria J. Villa de Brito
%A Nuno G. Oliveira
%A Matilde Castro
%A Judite Costa
%A Maria F. Cabral
%J Molecules
%D 2014
%I MDPI AG
%R 10.3390/molecules19010550
%X The purpose of this work was to synthesize and characterize the thiatetraaza macrocycle 1-thia-4,7,10,13-tetraazacyclopentadecane ([15]aneN 4S). Its acid-base behaviour was studied by potentiometry at 25 ¡ãC and ionic strength 0.10 M in KNO 3. The protonation sequence of this ligand was investigated by 1H-NMR titration that also allowed the determination of protonation constants in D 2O. Binding studies of [15]aneN 4S with Mn 2+, Fe 2+, Co 2+, Ni 2+, Cu 2+, Zn 2+, Cd 2+, Hg 2+ and Pb 2+ metal ions were further performed under the same experimental conditions. The results demonstrated that this compound has a higher selectivity and thermodynamic stability for Hg 2+ and Cu 2+, followed by Ni 2+. The UV-visible-near IR spectroscopies and magnetic moment data for the Co(II) and Ni(II) complexes indicated a tetragonal distorted coordination geometry for both metal centres. The value of magnetic moment and the X-band EPR spectra of the Cu(II) complex are consistent with a distorted square pyramidal geometry.
%K macrocyclic compounds
%K thiatetraaza
%K stability constants
%K spectroscopic studies
%K chelation therapy
%K mercury(II) chelator
%K copper(II) chelator
%U http://www.mdpi.com/1420-3049/19/1/550