Browsing by Author "Höppe, Henning A."

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    Two light-metal dihydrogenisocyanurate hydrates linked by diagonal relationship : syntheses, crystal structures, and vibrational spectra of Li[H2N3C3O3]·1.75 H2O and Mg[H2N3C3O3]2·8 H2O
    (2020) Reckeweg, Olaf; Lissner, Falk; Blaschkowski, Björn; Gross, Peter; Höppe, Henning A.; Schleid, Thomas
    Single‐crystalline materials of Li[H2N3C3O3]·1.75 H2O and Mg[H2N3C3O3]2·8 H2O were obtained by dissolving stoichiometric amounts of the respective carbonates with cyanuric acid in boiling water followed by gentle evaporation of excess water after cooling to room temperature. Even though both of these compounds crystallize in the triclinic space group P1 according to X‐ray structure analyses of their colorless and transparent single crystals, they adopt two new different structure types. Li[H2N3C3O3]·1.75 H2O exhibits the unit‐cell parameters a = 884.71(6) pm, b = 905.12(7) pm, c = 964.38(7) pm, α = 67.847(2)°, β = 62.904(2)° and γ = 68.565(2)° (Z = 4), whereas the lattice parameters for Mg[H2N3C3O3]2·8 H2O are a = 691.95(5) pm, b = 1055.06(8) pm, c = 1183.87(9) pm, α = 85.652(2)°, β = 83.439(2)° and γ = 79.814(2)° (Z = 2). In both cases, the singly deprotonated isocyanuric acid forms monovalent anions consisting of cyclic [H2N3C3O3]– units, which are arranged in ribbons typical for most hitherto known monobasic isocyanurate hydrates. The structures are governed by the oxophilic strength of the respective cation which means that they fulfil their oxophilic coordination requirements either solely with water molecules ([Mg(OH2)6]2+ for Mg2+) or with crystal water and one or two direct coordinative contacts to carbonyl oxygen atoms (O(cy)) of [H2N3C3O3]– anions ([(Li(OH2)2-3(O(cy)1-2]+ for Li+). In both structures occur dominant hydrogen bonds N-H···O within the anionic [H2N3C3O3]- ribbons as well as hydrogen bonds O-H···O between these ribbons and the hydrated Li+ and Mg2+ cations.
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    Y5F3[AsO3]4 and Y5Cl3[AsO3]4 : two non-isostructural yttrium halide oxoarsenates(III) and their potential as hosts for luminescent Eu3+- and Tb3+-doping
    (2025) Locke, Ralf J. C.; Mikuta, Martina; Ledderboge, Florian; Zimmer, Frank C.; Höppe, Henning A.; Schleid, Thomas
    Y5F3[AsO3]4 crystallizes needle-shaped in the tetragonal space group P4/ncc with the lattice parameters a = 1143.80(8) pm, c = 1078.41(7) pm and c/a = 0.9428 for Z = 4. The yttrium-fluoride substructure linked via secondary contacts forms a three-dimensional network 3∞{[Y5F3]12+} and the remaining part consists of ψ1-tetrahedral [AsO3]3- units, which leave lone-pair channels along [001]. In contrast, platelet-shaped Y5Cl3[AsO3]4 crystals adopt the monoclinic space group C2/c with the lattice parameters a = 1860.56(9) pm, b = 536.27(3) pm, c = 1639.04(8) pm and β = 105.739(3)° for Z = 4. Condensation of [(Y1,2)O8]13- polyhedra via four common edges each leads to fluorite-like 2∞ {[(Y1,2)Oe8/2]5-} layers spreading out parallel to the (100) plane. Their three-dimensional linkage occurs via the (Y3)3+ cations with their Cl- ligands on the one hand and the As3+ cations with their lone-pairs of electrons on the other, which also form within [AsO3]3- anions lone-pair channels along [010]. Both colorless compounds can be obtained by solid-state reactions from corresponding mixtures of the binaries (Y2O3, As2O3 and YX3 with X = F and Cl) at elevated temperatures of 825 °C, most advantageously under halide-flux assistance (CsBr for Y5F3[AsO3]4 and ZnCl2 for Y5Cl3[AsO3]4). By replacing a few percent of YX3 with EuX3 or TbX3, Eu3+- or Tb3+-doped samples are accessible, which show red or green luminescence upon excitation with ultraviolet radiation.