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  • 1
    Electronic Resource
    Electronic Resource
    Sodium aluminogermanate hydroxosodalite hydrate Na6+x[Al6Ge6O24](OH)x · nH2O (x ≈ 1.6, n ≈ 3.0): Synthesis, phase transitions and dynamical disorder of the hydrogen dihydroxide anion, H3O2-, in the Cubic high-temperature formDedicated to Professor Dietrich Mootz on his 60th Birthday. (1993)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 619 (1993), S. 1321-1329 
    Details
    ISSN: 0044-2313
    Keywords: Sodium aluminogermanate ; sodalite ; hydrogen dihydroxide anion ; crystal structure ; phase transition ; dynamical proton exchange ; MAS NMR ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Natriumalumogermanat-Hydroxosodalithhydrat Na6+x[Al6Ge6O24](OH)x · nH2O (x ≈ 1,6, n ≈ 3,0): Synthese, Phasenumwandlungen und dynamische Fehlordnung des Hydrogendihydroxid-Anions,H3O2-,in der kubischen HochtemperaturformKristallines Natriumalumogermanat-Hydroxosodalithhydrat Na6+x[Al6Ge6O24](OH)x · nH2O mit x ≈ 1,6 und n ≈ 3,0 wurde durch Reaktion von Al2O3, GeO2 und NaOH-Lösung unter hydrothermalen Bedingungen hergestellt und mit Hilfe der Simultanthermoanalyse, Dynamischen Differenz-Kalorimetrie (DSC), Röntgen- und Neutronenbeugung sowie 1H- und 23Na-MAS-NMR- und IR-Spektroskopie charakterisiert. Die Verbindung durchläuft eine reversible strukturelle Phasenumwandlung bei Tc = 166 K (Heizmodus), die tatsächlich, wie in DSC-Messungen festgestellt wurde, als komplexe Zweistufentransformation abläuft. Struktur-
    Notes: Crystalline sodium aluminogermanate hydroxosodalite hydrate Na6+x[Al6Ge6O24](OH)x · nH2O with x ≈ 1.6 and n ≈ 3.0 has been synthesized by reacting Al2O3, GeO2 and NaOH solution under hydrothermal conditions, and characterized by means of simultaneous thermal analysis, differential scanning calorimetry, X-ray and neutron diffraction as well as 1H and 23Na MAS NMR and IR spectroscopy. The material undergoes a reversible structural phase transition at Tc = 166 K (heating mode), which is actually a complex two-step transformation as detected in DSC measurements. Structure refinements of the cubic high-temperature form (cell constant a = 9.034(2) Å, room temperature) with single-crystal X-ray and powder neutron diffraction data have not yielded overall satisfactory results, probably due to the solid-solution character of the hydrosodalite. The refinements nevertheless demonstrate that (i) the sodalite host framework is a strictly alternating array of corner-linked AlO4 and GeO4 tetrahedra, and (ii) most polyhedral [4668] cavities are occupied by four sodium cations and one orientationally disordered hydrogen dihydroxide anion, H3O2-, which possesses a strong central hydrogen bond. Variable-temperature 1H MAS NMR spectra unambiguously confirm the presence of H3O2- ions and, in addition, reveal a dynamical intraionic exchange between the central and terminal protons and a rotational diffusion of those anions to occur in the high-temperature form. The nature of the guest complexes filling the remaining cages could not be unambiguously determined. Results are compared with those obtained in recent studies on the related sodium aluminosilicate hydrosodalite system of the general formula Na6+x[Al6Si6O24] (OH)x · nH2O.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19936190728
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  • 2
    Electronic Resource
    Electronic Resource
    [TMPA]4[Si8O20] · 34 H2O and [DDBO]4[Si8O20] · 32 H2O are heteronetwork clathrates with 1,1,4,4-tetramethylpiperazinium (TMPA) and 1,4-dimethyl-1,4-diazoniabicyclo[2.2.2]octane (DDBO) guest cations (1994)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 620 (1994), S. 757-765 
    Details
    ISSN: 0044-2313
    Keywords: Silicate hydrate ; 1,1,4,4-tetramethylpiperazinium ; 1,4-dimethyl-1,4-diazoniabicyclo[2.2.2]octane ; 1,1-dimethylpiperidinium ; clathrate ; crystal structure ; double four-ring silicate anion ; hydrogen bonding ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: [TMPA]4[Si8O20] · 34 H2O und [DDBO]4[Si8O20] · 32 H2O sind Heteronetzwerk-Clathrate mit 1,1,4,4-Tetramethylpiperazinium (TMPA) und 1,4-Dimethyl-1,4-Diazoniabicyclo[2.2.2]octan (DDBO) Gastkationen[TMPA]4[Si8O20] · 34 H2O (1) und [DDBO]4[Si8O20] · 32 H2O (2) wurden durch Kristallisation aus wäßrigen Lösungen der entsprechenden quartären Alkylammoniumhydroxide und SiO2 erhalten. Die Kristallstrukturen wurden mittels Einkristallröntgenbeugung bestimmt. 1: Monoklin, a = 16,056(2), b = 22,086(6), c = 22,701(2) Å, β = 90,57(1)° (T = 210 K), Raumgruppe C2/c, Z = 4. 2: Monoklin, a = 14,828(9), b = 20,201(7), c = 15,519(5) Å, β = 124,13(4)° (T = 255 K), Raumgruppe P21/c, Z = 2. Die Polyhydrate sind strukturverwandte Wirt-Gast-Verbindungen mit dreidimensionalen Wirtstrukturen aus über Wasserstoffbrücken verknüpften oligomeren Anionen [Si8O20]8- und H2O-Molekülen. Die Silicat-Anionen haben eine würfelförmige Doppelvierring-Struktur und eine lokale Umgebung, die von 24 H2O-Molekülen und sechs Kationen (TMPA, [C8H20N2]2+, oder DDBO, [C8H18N2]2+) gebildet wird. Die Kationen befinden sich als Gastspezies in großen, unregelmäßigen, käfigartigen Hohlräumen. Untersuchungen mittels der 29Si-NMR-Spektroskopie und der Trimethylsilylierungsmethode haben gezeigt, daß die gesättigten Lösungen von 1 und 2 hohe Anteile an Doppelvierring-Anionen enthalten. Derartige Anionen sind auch in der gesättigten Lösung des Heteronetzwerk-Clathrats [DMPI]6[Si8O18(OH)2] · 48,5 H2O (3) mit 1,1-Dimethylpiperidinium-Kationen (DMPI, [C7H16N]+) als Gastspezies enthalten.
    Notes: [TMPA]4[Si8O20] · 34 H2O (1) and [DDBO]4[Si8O20] · 32 H2O (2) have been prepared by crystallization from aqueous solutions of the respective quaternary alkylammonium hydroxide and SiO2. The crystal structures have been determined by single-crystal X-ray diffraction. 1: Monoclinic, a = 16.056(2), b = 22.086(6), c = 22.701(2) Å, β = 90.57(1)° (T = 210 K), space group C2/c, Z = 4. 2: Monoclinic, a = 14.828(9), b = 20.201(7), c = 15.519(5) Å, β = 124.13(4)° (T = 255 K), space group P21/c, Z = 2. The polyhydrates are structurally related host-guest compounds with three-dimensional host frameworks composed of oligomeric [Si8O20]8- anions and H2O molecules which are linked via hydrogen bonds. The silicate anions possess a cube-shaped double four-ring structure and a characteristic local environment formed by 24 H2O molecules and six cations (TMPA, [C8H20N2]2+, or DDBO, [C8H18N2]2+). The cations themselves reside as guest species in large, irregular, cage-like voids. Studies employing 29Si NMR spectroscopy and the trimethylsilylation method have revealed that the saturated aqueous solutions of 1 and 2 contain high proportions of double four-ring silicate anions. Such anions are also abundant species in the saturated solution of the heteronetwork clathrate [DMPI]6[Si8O18(OH)2] · 48.5 H2O (3) with 1,1-dimethylpiperidinium (DMPI, [C7H16N]+) guest cations.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19946200430
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