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  • 1
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 246 (1941), S. 243-257 
    ISSN: 0863-1786
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 1. Der zeitliche Verlauf der Reduktion von Molybdänlösungen mit Zn und Cd wird bei Gegenwart verschiedener Säuren untersucht. Aus Potentialmessungen geht hervor, daß die Reduktion zunächst zur Bildung von Mo(V) und dann bis Zum Mo(III). führt. Mo(IV) tritt nicht auf.
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 9 (1986), S. 308-309 
    ISSN: 0935-6304
    Keywords: High performance liquid chromatography, HPLC ; Reverse phase ; Internal standard ; Trimellitic anhydride ; Air sample ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Ill.
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 18 (1976), S. 1497-1506 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A chemostat in which mammalian cells can be raised in continuous suspension culture is described. It is constructed from commercially available parts. This apparatus has the advantage over earlier models in that the medium can be pumped off free of cells, thus suddenly increasing the cell concentration in the culture. The apparatus has been successfully used in studies on contact inhibition.
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  • 4
    ISSN: 1434-1948
    Keywords: Carbene complexes ; Carbyne complexes ; Asymmetric synthesis ; Carbohydrates ; Chiral auxiliaries ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Chiral carbene complexes [Cp(CO)2Mn=C(OR*)Ph] (4a-e) were prepared by reaction of [Cp(CO)2Mn=C(OAc)Ph] (2) with HOR* [HOR* = 1,2:3,4-di-O-isopropylidene-D-galactopyranose (3a), 2,3,4,6-tetra-O-acetyl-D-galactopyranose (3b), 2,3,4,6-tetra-O-acetyl-D-glucopyranose (3c), (S)- (3d) and (R)-1,2-O-isopropylideneglycerol (3e)]. The replacement of a CO ligand with PTol3 in 4a-e proceeded diastereoselectively to give [Cp(CO)(PTol3)Mn=C(OR*)Ph] (5a-e). The diastereoselectivity increased in the order a, b, c, d: de = 8% (5a), 33% (5b), 70% (5c), 〉 96% (5d). For (R)-5d the isomer with the (S) configuration at manganese (SMn) was formed predominantly. For (S)-5d, only (RMn,S)-5d was detected (de 〉 96%). Photolysis of (R)-4d in the presence of phosphites or phosphanes afforded (SMn)-[Cp(CO)(PR3)Mn=C(OR*)Ph] [PR3 = P(OPh)3 (8), P(OMe)3 (9), P(OMe)2Ph (10), P(OMe)Ph2 (11), PPh3 (12), P(C6H4Cl-p)3 (13)] with a de 〉 96%. Photolysis of (S)-4d in the presence of P(OMe)3 gave (RMn,S)-9. Complex (R)-14 [related to (R)-4d] was obtained from [Cp(CO)2Mn=C(OAc)Tol-p] and 3d. Replacement of CO by PR3 in (R)-14 gave (SMn,R)-[Cp(CO)(PR3)Mn=C(OR*)Tol-p] [R = Tol-p (15), OMe (16), C6H4Cl-p (17)] with a de 〉 96%. In solution, the PTol3-substituted complex 5d is configurationally stable whereas the P(OMe)3 complex 9 epimerizes slowly at room temperature in CH2Cl2, Et2O, and THF within about one week.
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  • 5
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 2000 (2000), S. 1113-1120 
    ISSN: 1434-193X
    Keywords: Peptidomimetics ; Reverse turn mimetics ; Glycomimetics ; Heterocycles ; Lactams ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: -D-Glucurono-3,6-lactone and L-cysteine combine in a highly stereoselective manner to give the 7,5-bicyclic thiazolidinlactam 2. The α-hydroxy group of the D-glucurono-3,6-lactone was exchanged for an amino function (to give 13) and, after condensation with L-cysteine methyl ester, the polyol dipeptide 7 was obtained. Peptide couplings proceed without the need to protect the three secondary hydroxy groups of the seven-membered ring. The amino group of 7 was deprotected and selectively elongated to the pseudo-tripeptide 16. The depsipeptide 17 was obtained by condensation of Boc-Ala-OH with the polyol 2. Elongation at the carboxy terminus yielded 19 and 20. The bicyclic scaffold populates a well-defined solution conformation; the hydroxy groups mimic the side chains of hydrophilic amino acids and can be further functionalized.
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  • 6
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 246 (1941), S. 258-274 
    ISSN: 0863-1786
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 1. Der Verlauf der elektrolytischen Reduktion von schwefel- und salzsauren Molybdänlösungen wird untersucht. Die Reduktion verläuft über die 5-wertige Stufe bis zum Mo(III). In sehr schwach sauren Lösungen führt sie unmittelbar zu festem Mo(OH)3.
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  • 7
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 451 (1979), S. 82-92 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On the Preparation and Suitability of Microspherical Silicas for the Column ChromatographyMicrospherical silicas with particle sizes up to 1 m̈m having nonspherical portions of ≤ 1 percent have been prepared using polyethoxysiloxane (polyester). An acid treatment of the hydrogels resulted in larger specific surfaces of the final products.The synthetized silica gels are excellently suitable for chromatographic purposes in dependence on their specific surface and their average pore diameter, resp.For the rapid determination of types of compounds by means of the micro fluorescent indicator adsorption analysis (MFIA) already crude gels could be used without any fractionation. Their specific surfaces had to be within the range of 500 ± 200 m2 g-1. For the use in the high performance liquid chromatography (HPLC) efficient supports should have specific surfaces in the range of 500 ± 300 m2 g-1. In this case the lower limiting value is determined by the capacity factors of the separation problem.Spheroids with surfaces of 200 ± 150 m2 g-1 have been obtained following the gel synthesis by hydrothermal treatment. These gels, however, were characterized by greater heights for theoretical plates in comparison with the initial gel.With gels, having surfaces in the range of 200 and 840 m2 g-1, the chromatographic investigation resulted in selectivity factors being independent of the surface. The capacity factors were strictly proportional to the specific surface of the support.
    Notes: Es wurde mikrosphärisches Silicagel mit Korngrößen bis zu 1 m̈m bei nichtsphärischen Anteilen ≤ 1% unter Verwendung von Polyäthoxysiloxan (Polyester) hergestellt. Saure Behandlung der Hydrogele führte zu höheren spezifischen Oberflächen der Endprodukte.Die synthetisierten Silicagele eigneten sich in Abhängigkeit von ihrer spezifischen Oberfläche bzw. ihrem mittleren Porendurchmesser ausgezeichnet zur Chromatographie.Für die schnelle Stoffgruppenbestimmung mittels Mikro-Fluoreszenzindikator-Adsorptionsanalyse (MFIA) konnten bereits Rohgele ohne Fraktionsierung Verwendung finden. Ihre spezifischen Oberflächen mußten innerhalb 500 ± 200 m2 g-1 liegen. Zum Einsatz in der schnellen Flüssigchromatographie (HPLC) sollten leistungsfähige Träger spezifische Oberflächen im Bereich 500 ± 300 m2 g-1 aufweisen. Hier richtet sich der untere Grenzwert nach den Kapazitätsfaktoren des Trennproblems.Sphäroide mit Oberflächen von 200 ± 150 m2 g-1 wurden im Anschluß an die Gelsynthese durch hydrothermales Altern gewonnen. Diese Gele zeigten jedoch im Vergleich zum Ausgangsgel größere theroretische Trennstufenhöhen.Die chromatographische Untersuchung ergab an Gelen mit Oberflächen zwischen 200 und 840 m2 g-1 oberflächenunabhängige Selektivitätsfaktoren. Die Kapazitätsfaktoren waren der spezifischen Trägeroberfläche streng proportional.
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  • 8
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 516 (1984), S. 55-66 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Photoelectron Spectroscopy on Niobium IodidesThe photoelectron spectra (AlKα, HeI) of NbI5, NbI4, Nb3I8, Nb6I11, HNb6I11, Nb6I8(CH3NH2)6, Nb6I8(C3H7NH2)6, and Nb are measured and discussed. It is shown that the binding energy of the niobium core levels depends linearly on the oxidation number n (n = I/Nb). The relation BE = 201.8 + 1.07 · n holds for the Nb 3d5/2 level. Using this relation the hydridic character of the hydrogen in HNb6I11 becomes plausible and the increased electron concentration of the Nb6I8 cluster in the compounds Nb6I8(CH3NH2)6 and Nb6I8(C3H7NH2)6 is verified. Energy gaps Eg = 0.40 (0.45) eV are found for Nb6I11(HNb6I11) and for the amines the top of the valence band is 0.70 (CH3NH2) and 0.68 eV (C3H7NH2), resp. below the Fermi level.
    Notes: Es werden die Photoelektronenspektren (AlKα, HeI) von NbI5, NbI4, Nb3I8, Nb6I11, HNb6I11, Nb6I8(CH3NH2)6, Nb6I8(C3H7NH2)6 und Nb gemessen und diskutiert. Es läßt sich zeigen, daß die Bindungsenergie BE der Niob-Rumpfniveaus linear von der Oxydationszahl n (n = I/Nb) abhängt; für das Nb 3d5/2-Niveau ergibt sich die Beziehung BE = 201,8 + 1,07 · n. Durch Anwendung dieser Beziehung wird der hydridartige Charakter des Wasserstoffs in HNb6I11 wahrscheinlich gemacht sowie die Zunahme der Elektronenkonzentration im Nb6I8-Cluster der Verbindungen Nb6I8(CH3NH2)6 und Nb6I8(C3H7NH2)6 belegt. Für Nb6I11(HNb6I11) ergibt sich eine verbotene Zone Eg = 0,40 (0,45) eV, für die Amine ist der Abstand der Oberkante des Valenzbandes zur Fermi-Kante 0,70 (CH3NH2) bzw. 0,68 eV (C3H7NH2).
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  • 9
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 462 (1980), S. 177-184 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Contributions to the Chemistry of Transition Metal Alkyl Compounds. XXX. Synthesis and Characterization of Nitrobenzyl Nickel Compounds(C2H5)2Ni · dipy reacts with benzyl chlorides forming complexes of the type RNiCl · dipy. In this way nitro groups containing thermally stable organonickel compounds can be obtained, which cannot be achieved by means of organolithiiim or Grignard reagents. - In a similar way (C2H5)Ni · dipy reacts with to form · dipy.The composition of the compounds achieved was proved by analysis, by characteristic reactions, magnetic moments, and in part by their IR and M spectra.
    Notes: (C2H5)2Ni · dipy reagiert mit Benzylchloriden zu Benzylnickelchlorid-Komplexen des Typs RNiCl · dipy. Auf diesem Wege sind auch Nitrogruppen enthaltende thermisch stabile Organonickelverbindungen zugängig, die mittels Organolithium-oder Grignardverbindungen nicht erhalten werden können. - Auf analoge Weise reagiert (C2H5)2Ni · dipy mit zu · dipy.Die Zusammensetzung der erhaltenen Verbindungen wurde analytisch, durch die magnetischen Momente sowie IR-Daten und M-Spektren und durch charakteristische Reaktionen gesichert.
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  • 10
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 483 (1981), S. 193-204 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Darstellung, Eigenschaften und ESCA-Charakterisierung von Vanadium-Oberflächenverbindungen an Silicagel. IIBindungsenergiewerte (BE) und Intensitätsverhältnisse in Vn/SiO2 (n = 3, 4 und 5) in Abhängigkeit von der Vanadium-Konzentration und Liganden L wurden untersucht. Die Ermittlung optimierter Produkte und ESCA-Proben wird beschrieben. Anhand dieser Ergebnisse werden die Bedingungen demonstriert, unter denen ESCA zuverlässige Informationen über feinverteilte Oberflächen-Verbindungen liefern kann.Der geeignete Konzentrationsbereich für wäßrige Dotierungen liegt zwischen 0,4 bis 1,2% VIII und 1,0 bis 1,2% für VV; in nichtwäßrigen (metallorganischen) Präparaten ergeben sogar 0,15 bis 0,4% VIII und 0,4% VV brauchbare Spektren. Die ESCA-Daten des Peroxo-Komplexes (≡Si—O)3V—(O2) (I) Bestätigen diese Trends.Außerordentlich feinverteilte Oberflächen-Verbindungen erhält man aus Dotierungen mit V[N(SiMe3)2]3. Hier ist eine Konzentration von 0,4 bis 0,5% VIII (oder VV) optimal und die obere Grenze.Beweise für die Formulierung von VnSiO2 als dreibeinige Oberflächen-Verbindungen sind zusammengefaßt; die Bedeutung des Additivitätsprinzips für die Erklärung und Voraussage elektronischer Verhältnisse bei Oberflächen-Verbindungen wird erläutert.Innerhalb der Serie (≡SiO)3V—L (mit L = ohne Liganden, =0, und —Oz) wurden die chemischen Verschiebungen für ≡Si—O—V (0,7 eV); V=O (0,6 eV) und V—(O2) (0,4 eV) ermittelt. Die BE-Beiträge einiger Donorliganden (und —Cl) werden abgeschätzt. In (I)deuten die ESCA-Daten eine formale Oxydationszahl nahe +4 an.Grenzen der ESCA-Methode werden erwähnt und Erweiterungen des Additivitätsprinzips diskutiert.
    Notes: Binding energy (BE) behavior and signal intensity as function of V conc. and ligands L were critically examined in Vn/SiO2 species (where n = +5, +4, and +3) and securing of optimized products and ESCA samples is described. The results moreover demonstrate conditions and approaches whereby ESCA can provide reliable information on highly diluted surface compound systems.From aquous media 1.0-1.2 wt. % VV and 0.4-1.2 wt. % VIII proved to be preferred ranges whereas in non aqueous (metalorganic) preparates the surprisingly low concentration of 0.4-0.15 wt. % VIII gave usable spectra and even 0.4 wt. % VV could be measured. ESCA data with the peroxo complex (≡Si—O)3V—(O2) (I) confirmed these trends.Superiorly subdivided surface compounds (reflected in the quality of spectra) are obtainable from V[N(SiMe3)2]3 impregnations where 0.4-0.5 wt. % VIII (or VV) are maximum/optimum conc. limits.Evidence for formulating Vn/SiO2 as three legged surface compounds is summarized and diagnostic/predictive uses of the additivity principle for surface electron states illustrated.In the (≡Si—O)3V—L series, where L = none, =O, and —(O2) positive ΔBE shifts for ≡Si—O—V (0.7 eV); V=O (0.6 eV); and V—(O2) (0.4 eV) were estimated. Tentative BE contributions of some donor ligands (and —Cl) are also suggested. In (I) ESCA indicated a formal oxidation state of approx. +4.Certain limits (precautions) with ESCA are noted and extensions of the additivity relationship discussed.
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