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  • Electronic Resource  (13)
  • 1990-1994  (13)
  • preparation  (8)
  • Analytical Chemistry and Spectroscopy  (5)
  • 1
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 596 (1991), S. 89-92 
    ISSN: 0044-2313
    Keywords: Calcium oxychloride ; preparation ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: An Oxychloride of Calcium: Ca4OCl6Ca4OCl6 (hexagonal, P63mc, Z = 2), a = 905.8(3), c = 686.3(4) pm, (R = 0.031) crystallizes as colourless needles from reducing melts (CaCl2, Ca) that contain small amounts of „oxygen“. It contains „isolated“ tetrahedral units [Ca4O] and is isotypic with e.g., Ba4OCl6, Yb4OCl6 and K6HgS4. Ca4OCl6 does not form in the dehydration process of, for example, CaCl2 · 6 H2O.
    Notes: Ca4OCl6 (hexagonal, P63mc, Z = 2, a = 905.8(3)); c = 686.3(4) pm, (R = 0,031) kristallisiert in Form farbloser Nadeln aus „reduzierenden Schmelzen“ (CaCl2, Ca), die wenig „Sauerstoff“ enthalten. Es enthält „isolierte“ tetraedrische [Ca4O]-Einheiten und ist isotyp mit z. B. Ba4OCl6, Yb4OCl6 oder K6HgS4. Ca4OCl6 entsteht nicht beim Entwässern von z. B. CaCl2 · 6 H2O.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 15 (1992), S. 637-640 
    ISSN: 0935-6304
    Keywords: Capillary GC ; On-column injection ; Plasma samples ; Retinoid analysis ; Acitretin isomers ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The capillary gas chromatographic (CGC) analysis of the der-matological drug trans-acitretin (NeotigasonR) and its cis metabolite is described. Separation of the methyl ester derivatives can be achieved on a 90% biscyanopropylsiloxane phase. The importance of using cold on-column injection and short, thin film capillary columns is discussed. For patients treated with the prodrug of acitretin, etretinate (TigasonR), i.e. the ethyl ester of Neotigason, three compounds have to be separated. Selectivity tuning is required for successful CGC separation. An alternative can be found in the selectivity of ion monitoring mass spectroscopy. Analysis of plasma samples involves liquid-liquid extraction, a derivatization step, and HPLC purification.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 16 (1993), S. 491-494 
    ISSN: 0935-6304
    Keywords: Supercritical fluid extraction ; Polynuclear aromatic hydrocarbons ; Liquid/solid traps ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Polynuclear aromatic hydrocarbons (PAHs) are recovered from a soil with a high carbon content (ca. 50%) with supercritical fluid extraction (SFE) as well as with conventional Soxhlet extraction. The influence of temperature and modifier volume on SFE efficiency and the effect of a combined liquid/solid trap for analyte collection are investigated in this study. Such traps, which make analyte collection and clean-up possible in one step, are compared with conventional analyte collection in pure organic solvents. A comparison between reproducibility and efficiency of SFE and Soxhlet extraction is presented.
    Additional Material: 5 Ill.
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  • 4
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The intact ion yields of phosphotyrosine, phosphothreonine and mono- and diphosphoserine residue-containing peptides have been compared with the non-phosphorylated sequences using plasma desorption mass spectrometry. Equimolar mixtures of the phosphorylated (MP) and non-phosphorylated peptides (M) were also analysed. The positive mass spectra of these mixtures show a higher intensity of the [M + H]+ compared with the [MP + H]+. In the negative mass spectrum, the bias towards the [M - H]- compared with the [MP - H]- was reduced, but the spectra generally did not accurately reflect the stoichiometry.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 27 (1992), S. 1148-1150 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 3 Ill.
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  • 6
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 602 (1991), S. 31-37 
    ISSN: 0044-2313
    Keywords: Alkali-iodoindates(III) ; indium ; preparation ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis and Crystal Structures of the Alkali-tetraiodoindates(III), AInI4 (A = Li, K, Rb, Cs)Single crystals of the yellow alkaliiodoindates(III), AInI4 (A = Li, K, Rb, Cs), are obtained from mixtures of the binary components by slow cooling of the melts. LiInI4 is isotypic with LiAlCl4: monoclinic, P21/c, Z = 4; a = 838.9(4); b = 751.2(3); c = 1526,7(8) pm; β = 92.67(4)°. KInI4 belongs to the ATIX4 type of structure (A = NH4, K, Rb; X = Br, I): cubic, F4 3c, Z = 24; a = 1990.8(1) pm. RbInI4 crystallizes with the β-GaBr2 type: trigonal, R3c, Z = 18; a = 2452.6(6); c = 978.6(4) pm. CsInI4 is isostructural with CsTII4: monoclinic, P21/c, Z = 4; a = 738.4(1); b = 1875.7(3); c = 853.6(2) pm; β = 105.75(2)°. In all structures almost regular tetrahedral polyhedra [InI4]- occur. The coordination numbers of the alkali cations cover the wide range from 6 (Li+) via 9 (Rb+) and 11 (Cs+) to 12 (K1+).
    Notes: Einkristalle der gelben Iodoindate(III) der Alkalimetalle, AInI4 (A = Li, K, Rb, Cs), erhält man aus Gemengen der binären Komponenten durch langsames Abkühlen der Schmelzen. LiInI4 ist isotyp mit LiAlCl4: monoklin, P21/c, Z = 4; a = 838,9(4); b = 751,2(3); c = 1526,7(8) pm; β = 92,67(4)°. KInI4 gehört zum ATIX4-Typ (A= NH4, K, Rb; X= Br, I): kubisch, F4 3c, Z = 24; a = 1990,8(1) pm. RbInI4 kristallisiert im β-Ga[GaBr4]-Typ: trigonal, R3c, Z = 18; a = 2452,6(6); c = 978,6(4) pm. CsInI4 ist isotyp mit CsTII4: monoklin, P21/c, Z = 4; a = 738,4(1); b = 1875,7(3); c = 853,6(2) pm; β = 105,75(2)°. Stets liegen annähernd tetraedrische Baugruppen [InI4]- vor. Die Koordinationszahlen der Alkali-Kationen überstreichen das Spektrum von 6 (Li+) über 9 Rb+, 11 (Cs+) bis 12 (K1+).
    Additional Material: 6 Tab.
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  • 7
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 620 (1994), S. 262-265 
    ISSN: 0044-2313
    Keywords: Ca3(BN2)2 ; Sr3(BN2)2 ; NaSr4(BN2)3 ; preparation ; structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On the Structure of Sr3(BN2)2The structure of Sr3(BN2)2 was determined on single-crystal X-ray data collected with a four-circle diffractometer. Sr3(BN2)2 crystallizes in the cubic space group Im3m (no. 229) with a = 764.56(3) pm and Z = 3. The structure contains linear BN3-2 ions with a B—N bond length of 135.8(6) pm. The straight forward synthesis employing metal nitrides plus boron nitride yielded crystalline powders of M3(BN2)2 (M = Ca, Sr) at 1100°C (5 days). Cubic indexing of guinier patterns gave a = 765.8(1) pm for M = Sr and a = 734.7(2) pm for M = Ca. The structure refinement on a single crystal of Sr3(BN2)2 revealed that one strontium site (2a; 0, 0, 0) is occupied by only about 50%. It has been tried to fully occupy this site with an alkali metal (A) to obtain ASr4(BN2)3 (Z = 2). Reactions with A = Na yielded crystalline powders. Cubic indexing of the guinier pattern analogous to that of Sr3(BN2)2 gave a = 754.2(1) pm.
    Notes: Die Struktur von Sr3(BN2)2 wurde anhand von Einkristall-Röntgendaten, die durch Messung an einem Vierkreisdiffraktometer erhalten wurden, bestimmt. Sr3(BN2)2 kristallisiert in der kubischen Raumgruppe Im3m (Nr. 229) mit a = 764,56(3) pm und Z = 3. Die Struktur enthält lineare BN3-2-Ionen mit einer Bindungslänge B—N von 135,8(6) pm. Die gezielte Darstellung aus den Metallnitriden und Bornitrid zu M3(BN2)2 (M = Ca, Sr) bei 1100°C (5 Tage) ergab kristalline Pulver. Kubische Indizierung der Guinierdiagramme gab a = 765,8(1) pm für M = Sr und 734,7(2) pm für M = Ca. Die Strukturverfeinerung an einem Einkristall von Sr3(BN2)2 zeigte, daß eine Strontiumlage (2a; 0,0,0) nur zu etwa 50% besetzt ist. Es wurde versucht, diese Lage mit einem Alkalimetall (A) entsprechend ASr4(BN2)3 (Z = 2) vollständig zu besetzen. Reaktionen mit A = Na ergaben kristalline Pulver, deren Guinierdiagramme analog zu Sr3(BN2)2 kubisch mit a = 754,2(1) pm indiziert werden konnten.
    Additional Material: 2 Ill.
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  • 8
    ISSN: 0044-2313
    Keywords: Alkali uranium halides, A2UX5 (A = K, Rb; X = Cl, Br, I) ; preparation ; crystal structure ; magnetic susceptibility ; UV-Vis spectra ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthese, Kristallstruktur, Magnetismus und Absorptionsspektren von Halogeniden des Typs A2UX5 (A = K, Rb; X = Cl, Br, I)Die ternären Uran(III)-halogenide A2UX5 (A = K, Rb; X = Cl, Br, I) wurden aus den binären Komponenten AX und UX3 in verschweißten Tantalampullen gewonnen. Nach Guinier-Aufnahmen (Raumtemperatur) kristallisieren sie sämtlich im K2PrCl5/Y2HfS5-Typ. Einkristall-Strukturverfeinerungen wurden für K2UI5 und Rb2UCl5 unternommen. Magnetische Suszeptibilitätsmessungen erfolgten mit einem SQUID-Magnetometer von Raumtemperatur bis zur Temperatur des flüssigen Heliums: Eindimensionale (innerhalb einer Kette) und dreidimensionale antiferromagnetische Ordnung wird bei tiefen Temperaturen, abhängig vom Abstand U3+—U3+, beobachtet. Absorptionsspektren wurden zwischen 4000 und 28000 cm-1 aufgenommen. Sie zeigen die für U3+ charakteristischen Übergänge und, abhängig vom Halogenid, sehr starke f - d Übergänge oberhalb 14000 bzw. 15000 cm-1.
    Notes: The ternary uranium(III) halides A2UX5 (A = K, Rb; X = Cl, Br, I) have been prepared from the binary components AX and UX3 in sealed tantalum containers. According to their Guinier X-ray powder patterns, they all crystallize with the K2PrCl5/Y2HfS5 type of structure. Lattice constants for ambient temperature are reported. Single-crystal structure refinemens were undertaken for K2UI5 and Rb2UCl5. Magnetic susceptibility data were recorded with a SQUID magnetometer from liquid helium to room temperature. One-dimensional (intrachain) and three-dimensional antiferromagnetic ordering occur at low temperatures dependent upon the U3+—U3+ distance. Absorption spectra were recorded between 4 000 and 28 000 cm-1. They show f - f transitions typical for U3+ and, depending on the halide, very strong f - d transitions above 14 000 to 15 000 cm-1, respectively.
    Additional Material: 8 Ill.
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  • 9
    ISSN: 0044-2313
    Keywords: Rhenium ; rubidium rhenium halide hydrates ; preparation ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: [Rb2(H2O)2][Re3(μ-Cl)3Br7(H2O)2]2 · H2O, a Mixed Halide-Hydrate with the Anionic Dimer {[Re3(μ-Cl)3Br7(H2O)2]2 · H2O}2-[Rb2(H2O)2][Re3(μ-Cl)3Br7(H2O)2]2 · H2O crystallizes as dark redbrown single crystals from an hydrobromic-acid solution of ReCl3 and RbBr at 0°C. An important feature of the crystal structure (monoclinic, C2/c; a = 1494.61(8); b = 835.71(4); c = 3079.96(19) pm; β = 97.801(4)°; Vm = 573.9(4) cm3mol-1; R = 0.060; Rw = 0.038) is the connection of two anions [Re3(μ-Cl)3Br7(H2O)2]- via a water molecule to dimers, {[Re3(μ-Cl)3Br7(H2O)2]2 · H2O}2-. These dimeric units are contained in slabs that are stacked in the [001] direction and held together by Rb+ cations and crystal water.
    Notes: [Rb2(H2O)2][Re3(μ-Cl)3Br7(H2O)2]2 · H2O kristallisiert in dunklen, rotbraunen Einkristallen aus bromwasserstoffsaurer Lösung von Rheniumtrichlorid und Rubidiumbromid bei 0°C. Ein wichtiges Merkmal der Kristallstruktur (monoklin; C2/c; a = 1494,61(8); b = 835,71(4); c = 3079,96(19) pm; β = 97,801(4)°; Vm = 573,9(4) cm3mol-1; R = 0,060; Rw = 0,038) ist die Verknüpfung zweier Anionen [Re3(μ-Cl)3Br7(H2O)2]- über ein Wassermolekül zu Dimeren {[Re3(μ-Cl)3Br7(H2O)2]2 · H2O}2-. Diese dimeren Baugruppen sind zu Schichtpaketen zusammengefaßt, die längs [001] gestapelt und über die Rb+-Ionen in Gemeinsamkeit mit Kristallwasser verbunden sind.
    Additional Material: 3 Ill.
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  • 10
    ISSN: 0044-2313
    Keywords: Polyphosphides ; Zintl-phases M3X11 (M = Na, K, Rb, Cs; X = P, As) ; P113-, As113- cage anion ; preparation ; vibrational spectra ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Chemistry and Structural Chemistry of Phosphides and Polyphosphides. 53. Preparation, Properties, and Vibrational Spectra of the Cage Anions P113- and As113-The Zintl-phases M3X11 (M = Na, K, Rb, Cs; X = P, As) are prepared from the elements or from M3X7 and X. The compounds undergo a first-order phase transition from the crystalline to the plastically crystalline state. Unit cell and space group of both modifications and the transition temperature Tc are determined. The vibrational spectra of the crystalline compounds and the Raman spectrum of the P113- anion in en-solution as well are measured. The assignment of the frequencies is given, based on the 32-D3 symmetry of the X113- cage anion. Normal coordinate analysis is carried out in terms of Cartesian coordinates to avoid the problem of redundancies in using internal coordinates. The force constants [mdyn Å-1] obtained for the characteristic bonds r, s, and t are: fppr = 1.34, fpps = 1.20, fppt = 1.08; fAsAsr = 1.1, fAsAss = 0.91. Normal vibrations and the potential energy distribution (PED) are discussed.
    Notes: Die Zintl-Phasen M3X11 (M = Na, K, Rb, Cs; X = P, As) werden aus den Elementen oder aus M3X7 und X synthetisiert. Die Verbindungen durchlaufen einen Phasenübergang 1. Ordnung vom kristallinen zum plastisch-kristallinen Zustand. Elementarzelle und Raumgruppe beider Modifikationen sowie Übergangstemperaturen Tc wurden bestimmt. Die Schwingungsspektren der kristallinen Verbindungen sowie das Raman-Spektrum des Anions P113- in en-Lösung wurden gemessen. Die Zuordnung der Schwingungsfrequenzen gelingt auf der Basis der Symmetrie 32-D3 der Käfiganionen X113-. Die Normalkoordinatenanalyse erfolgte in kartesischen Koordinaten, wodurch das in inneren Koordinaten auftretende Redundanzproblem vermieden wird. Auf diesem Wege erhaltene Kraftkonstanten [mdyn Å-1] der charakteristischen Bindungen r, s und t sind: fppr = 1, 34, fpps = 1, 20, fppt = 1, 08; fAsAsr = 1, 1, fAsAss = 0, 96, fAsAst = 0, 91. Die Normalschwingungen und die Verteilung der potentiellen Energie (PED) werden diskutiert.
    Additional Material: 4 Ill.
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