title: Chelation of ThIV, EuIII and NdIII by dianionic N,N'-bis(pyridoxylideneiminato)ethylene, (Pyr2en)2-. On the search of feasible modelings for heavy metals damage inhibition in living beings.
abstract: The neutral Schiff base N,N'-bis(pyridoxylideneiminato)ethylene {H(2)pyr(2)en} reacts with Th(NO(3))4.4H2O, NdCl3.6H2O and EuCl3.6H2O to give [Th(pyr(2)en)2(H2O)] (1), [Nd(pyr(2)en)(Hpyr(2)en)].12H2O (2) and [Eu(pyr(2)en)(Hpyr(2)en)] (3). In the three not yet reported bimolecular chelate systems the endo hydroxyl groups of the rings undergo deprotonation confirming the remarkable ability of the pyridoxal-containing ligand H(2)pyr(2)en to yield stable heavy metal chelates with unusual coordination polyhedra. Complexes 2 and 3 show a coordination number 8 for Nd and Eu, achieving a distorted quadratic antiprism. In complex 1 the additional water molecule increases the coordination number of Th to 9 producing a capped square antiprism. The synthesis and structural elucidation of the title complexes starting from a probably non-toxic metabolite like H(2)pyr(2)en should represent a useful contribution to the research on models of prevention and therapy of damage caused by radioactive and heavy elements.
authors.affiliation: Departamento de Química, Laboratório de Materiais Inorgânicos, Universidade Federal de Santa María, 97105-900 Santa Maria, RS, Brazil.
authors.forename: Davi Fernando
authors.initials: DF
authors.lastname: Back
authors.forename: Elida
authors.initials: E
authors.lastname: Bonfada
authors.forename: Gelson Manzoni
authors.initials: GM
authors.lastname: de Oliveira
authors.forename: Ernesto Schulz
authors.initials: ES
authors.lastname: Lang
mesh_terms: D000818:Animals; D000838:Anions / Q000737:chemistry; D002614:Chelating Agents / Q000138:chemical synthesis / Q000737:chemistry* / Q000627:therapeutic use; D005030:Ethylenes / Q000737:chemistry*; D005063:Europium / Q000737:chemistry* / Q000506:poisoning; D006801:Humans; D015394:Molecular Structure; D009354:Neodymium / Q000737:chemistry* / Q000506:poisoning; D011041:Poisoning / Q000517:prevention & control; D013910:Thorium / Q000737:chemistry* / Q000506:poisoning
chemical_list: D000838:Anions; D002614:Chelating Agents; D005030:Ethylenes; D009354:Neodymium; D005063:Europium; D013910:Thorium; C036216:ethylene