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  • 1
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Applied Organometallic Chemistry 3 (1989), S. i 
    ISSN: 0268-2605
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Applied Organometallic Chemistry 9 (1995), S. 581-590 
    ISSN: 0268-2605
    Keywords: inorganic tin ; monomethyltin cation ; model studies ; salt marsh ; sediment ; Spartina alterniflora ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: This study describes experiments on sedimentestuarine water slurries originating from a Spartina alterniflora salt marsh. We investigated the fate of tin(IV) or monomethyltin cation (MeSn3+) chlorides after their additon to slurries under anaerobic and aerobic conditions. We did not observe methylation of tin in anaerobic or aerobic slurries with and without added tin(IV). MeSn3+-amended samples occasionally formed small amounts of Me2Sn2+ or Me3Sn+ after extended periods of time, particularly when MeSn3+ remained in solution. The stability of MeSn3+ in slurries demonstrates that the absence of net methylation of tin(IV) is not due to rapid demethylation of MeSn3+ or its further methylation. Inorganic tin concentrations in the aqueous phase of anaerobic slurries spiked with MeSn3+ and unspiked slurries decreased by about 85% in 21 days and remained relatively constant until the end of the 59-day experiments. In similar anaerobic experiments about 25% of the MeSn3+ spike was adsorbed to sediment within 1 h and about 75% was adsorbed within 10 days. The lack of methylation and demethylation reactions in our aerobic and anaerobic slurries, which contrasts with two previous reports, undoubtedly reflects the absence of added nutrients and low concentrations of added tin(IV) in our experiments. We believe that our model experiments more accurately reflect conditions in salt marshes than do previous studies. We conclude that future model studies on methylation of inorganic tin should include. S. alterniflora because it is so prominent in observations of methyltin compounds in the estuary.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The electronic spectrum and the polarisation of the transitions have been determined in the region from 15000 to 50000 cm-1 for the 2-acetamino derivative of trans-15, 16-dimethyl-dihydropyrene, whose spectrum resembles closely that of the parent compound and its di-ethyl analogue. It is shown that the sequence of states is 1Lb, 1La, 1Bb, 1Ba, in agreement with theoretical predictions which were deduced from a configuration interaction model for the D2h-π-perimeter of these systems. The influence of inductive and hyperconjugative effects on the band positions and the band intensities has been discussed.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The electronic spectra and the polarisation of the transitions have been determined for the 1,6-methano-[11] annulenium cation III and the 4,6-dimethyl-1,2-benzotropylium cation IV. The observed sequence of polarisation of the prominent bands corresponding to the lowest electronically excited states is in agreement with the predictions derived from molecular orbital models of the PARISER-PARR-POPLE type. The influence of partial conjugation between the bridged centre and of the inductive effect of the methylene group in III has been investigated.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 55 (1972), S. 921-937 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Irradiation of Δ5,7-9α, 10β-steroids in solution with λ = 253,7 nm yielded no Δ5,7-9β, 10α-steroids and vice versa. No back reaction from precalciferol2 to ergosterol could be detected by kinetic measurements. This leads to the conclusion that with the mercury resonance line only ring opening and 6,7-cis/trans isomerization but no ring closure occurs.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Retentionsindices und ΔI-Werte von 59 Kohlenwasserstoffen verschiedener Ringsysteme, die in entsprechenden Fraktionen flüssiger Crackprodukte der Äthylenerzeugung vorkommen bzw. bei der thermischen Homo- und Codimierisierung der darin enthaltenen cyclischen und acyclischen Diene entstehen, wurden bei 60° an Kapillarsäulen mit Squalan und Polypropylenglykol 425 vermessen. Die Ergebnisse werden mitgeteilt und Zusammenhänge zwischen Kohlenwasserstoffstruktur und ΔI-Werten diskutiert.Für die untersuchten endo- und exo-Norbornene wird an Hand der ΔI-Werte gezeigt, daß eine Epimerenzuordnung mit Hilfe der Kapillar-Gaschromatographie möglich ist.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 316 (1974), S. 13-18 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Die Addition von Oxalessigester an 2,4; 3,5-Di-O-benzyliden-al-D-xylose 1 führt zum 3-Äthoxycarbonyl-3-desoxy-5,7; 6,8-di-O-benzyliden-D-gulo-oktulosonsäure-äthylester 2, aus dem man durch Erwärmen mit verd. Salzsäure in Dioxan die 2-Desoxy-D-gulo-heptose 3 erhält. Beim Schütteln mit konz. Salzsäure und Benzylmercaptan entsteht aus 3 unter Abspaltung von Wasser das [2-Hydroxymethyl-furanyl(5)]-acetaldehyd-dibenzylmercaptal 6. Der Ketosäureester 2 kann in einer Keto-(2 a) und in einer Enol-Form 2 b auftreten. Von letzterer leiten sich das 2,4-Di-O-acetat 4 und der 2,4-Di-O-methyläther 5 ab. Die D-gulo-Konfiguration der Verbindungen 2, 3, 4 und 5 wird durch Überführen des Methyläthers 5 in den O-Methyl-L-äpfelsäure-bis-(p-bromphenacylester) 10 bewiesen.
    Type of Medium: Electronic Resource
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