title: Synthesis of Coordination Polymers of Tetravalent Actinides (Uranium and Neptunium) with a Phthalate or Mellitate Ligand in an Aqueous Medium.
abstract: Four metal-organic coordination polymers bearing uranium or neptunium have been hydrothermally synthesized from a tetravalent actinide chloride (AnCl4) and phthalic (1,2-H2bdc) or mellitic (H6mel) acid in aqueous media at 130 °C. With the phthalate ligand, two analogous assemblies ([AnO(H2O)(1,2-bdc)]2·H2O; An = U4+(1) or Np4+(2)) have been isolated, in which the square-antiprismatic polyhedra of AnO8are linked to each other via μ3-oxo groups with an edge-sharing mode to materialize infinite zigzag ribbons. The phthalate molecules play a role in connecting the adjacent zigzag chains to build a two-dimensional (2D) network. Water molecules are bonded to the actinide center or found intercalated between the layers. With the mellitate ligand, two distinct structures have been identified. The uranium-based compound [U2(OH)2(H2O)2(mel)] (3) exhibits a three-dimensional (3D) structure composed of the dinuclear units of UO8polyhedra (square antiprism), which are further linked via the μ2-hydroxo groups. The mellitate linkers use their carboxylate groups to connect the dinuclear units, eventually building a 3D framework. The compound obtained for the neptunium mellitate ([(NpO2)10(H2O)14(Hmel)2]·12H2O (4)) reveals oxidation of the initial NpIVto NpVunder the applied hydrothermal synthetic conditions, yielding the neptunyl(V) (NpO2+) unit with a pentagonal-bipyramidal NpO7environment. This further leads to the formation of a layered assembly of the square-frame NpO7sheets via the bridging oxygen atoms from the neptunyl oxo groups, which further coordinate to the pentagonal equatorial coordination plane of the adjacent neptunium unit (i.e., cation-cation interactions). In compound 4, the mellitate molecules act as bridging linkers between the NpO7sheets by using four of their carboxylage groups, eventually building up a 3D structure.
authors.affiliation: Unité de Catalyse et Chimie du Solide (UCCS), UMR, CNRS 8181, Université de Lille, École Nationale Supérieure de Chimie de Lille, Centrale Lille, Université Artois , 59000 Lille, France.
authors.forename: Nicolas P
authors.initials: NP
authors.lastname: Martin
authors.affiliation: Institute of Resource Ecology, HDZR - Helmholtz-Zentrum Dresden-Rossendorf , Bautzner Landstrasse 400, 01328 Dresden, Germany.
authors.forename: Juliane
authors.initials: J
authors.lastname: März
authors.affiliation: Unité de Catalyse et Chimie du Solide (UCCS), UMR, CNRS 8181, Université de Lille, École Nationale Supérieure de Chimie de Lille, Centrale Lille, Université Artois , 59000 Lille, France.|Institut Universitaire de France , 1 rue Descartes, 75231 Paris Cedex 05, France.
authors.forename: Christophe
authors.initials: C
authors.lastname: Volkringer
authors.affiliation: Unité de Catalyse et Chimie du Solide (UCCS), UMR, CNRS 8181, Université de Lille, École Nationale Supérieure de Chimie de Lille, Centrale Lille, Université Artois , 59000 Lille, France.
authors.forename: Natacha
authors.initials: N
authors.lastname: Henry
authors.affiliation: Institute of Resource Ecology, HDZR - Helmholtz-Zentrum Dresden-Rossendorf , Bautzner Landstrasse 400, 01328 Dresden, Germany.
authors.forename: Christoph
authors.identifier: http://orcid.org/0000-0001-6393-2778
authors.initials: C
authors.lastname: Hennig
authors.affiliation: Institute of Resource Ecology, HDZR - Helmholtz-Zentrum Dresden-Rossendorf , Bautzner Landstrasse 400, 01328 Dresden, Germany.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Ikeda-Ohno
authors.affiliation: Unité de Catalyse et Chimie du Solide (UCCS), UMR, CNRS 8181, Université de Lille, École Nationale Supérieure de Chimie de Lille, Centrale Lille, Université Artois , 59000 Lille, France.
authors.forename: Thierry
authors.identifier: http://orcid.org/0000-0001-8175-3407
authors.initials: T
authors.lastname: Loiseau