title: Structure and stability range of a hexanuclear Th(IV)-glycine complex.
abstract: A hexanuclear Th(IV)-glycine complex was observed by Th L(3)-edge EXAFS measurements in an aqueous solution. Within the stability range of this complex the positively charged hexanuclear species [Th(6)(μ(3)-O)(4)(μ(3)-OH)(4)(H(2)O)(6)(Gly)(6)(HGly)(6)](6+) was preserved in a crystal with the composition [Th(6)(μ(3)-O)(4)(μ(3)-OH)(4)(H(2)O)(6)(Gly)(6)(HGly)(6)]·(NO(3))(3)(ClO(4))(3)(H(2)O)(3). This complex appears as a result of a competing reaction between hydrolysis and ligation by glycine. At a pH value below the stability range of the hexanuclear complex, crystals with the composition [Th(H(2)O)(3)(HGly)(3)]·(ClO(4))(4)H(2)O were obtained from the solution. Three water molecules in the thorium coordination sphere indicate that this complex occurs prior to the onset of Th(IV) hydrolysis.
authors.affiliation: Helmholtz-Zentrum Dresden-Rossendorf, Institute of Resource Ecology, Bautzner Landstr. 400, D-01314 Dresden, Germany. hennig@esrf.fr
authors.forename: Christoph
authors.initials: C
authors.lastname: Hennig
authors.forename: Shinobu
authors.initials: S
authors.lastname: Takao
authors.forename: Koichiro
authors.initials: K
authors.lastname: Takao
authors.forename: Stephan
authors.initials: S
authors.lastname: Weiss
authors.forename: Werner
authors.initials: W
authors.lastname: Kraus
authors.forename: Franziska
authors.initials: F
authors.lastname: Emmerling
authors.forename: Andreas C
authors.initials: AC
authors.lastname: Scheinost
mesh_terms: D003460:Crystallization; D005998:Glycine / Q000737:chemistry*; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000737:chemistry*; D012996:Solutions; D013910:Thorium / Q000737:chemistry*; D056928:X-Ray Absorption Spectroscopy; D014961:X-Ray Diffraction
chemical_list: D009942:Organometallic Compounds; D012996:Solutions; D013910:Thorium; D005998:Glycine