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  • 1
    Electronic Resource
    Electronic Resource
    Ab initio molecular orbital studies of nonidentity allyl transfer reactions (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Computational Chemistry 16 (1995), S. 1045-1054 
    Details
    ISSN: 0192-8651
    Keywords: Computational Chemistry and Molecular Modeling ; Biochemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Computer Science
    Notes: Ab initio molecular orbital (MO) calculations are carried out on the nonidentity allyl transfer processes, X- + CH2CHCH2Y ⇌ CH2CHCH2 X + Y-, with X- = H, F, and Cl and Y = H, NH2, OH, F, PH2, SH, and Cl. The Marcus equation applies well to the allyl transfer reactions. The transition state (TS) position along the reaction coordinate and the TS structure are strongly influenced by the thermodynamic driving force, whereas the TS looseness is originated from the intrinsic barrier. The intrinsic barrier, ΔE0
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcc.540160811
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  • 2
    Electronic Resource
    Electronic Resource
    Theoretical studies on the acid hydrolysis of methyl carbamatePart 45 in the series, Determination of Reactivity by MO Theory. (1987)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Computational Chemistry 8 (1987), S. 794-800 
    Details
    ISSN: 0192-8651
    Keywords: Computational Chemistry and Molecular Modeling ; Biochemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Computer Science
    Notes: The mechanism of the A2 acid hydrolysis of methyl carbamate was investigated using MNDO method. The reaction was found to proceed in two steps: (1) the rate-determining nucleophilic attack of water on the carbonyl carbon of the N-protonated tautomer involving the tetrahedral TS; and (2) the fast subsequent proton abstraction by the leaving group, NH3, to form products. The mechanism is similar to that involved in the A2 hydrolysis of acetamide. Effects of substituents, R1, R2, and R3 in R1OCONR2R3, on rates can be predicted by the changes in electron densities on alkoxy oxygen and N, in complete agreement with the experimental results. We concluded that there is no need for invoking two different mechanisms for amides and carbamates since a common mechanism can easily accommodate all the experimental results.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcc.540080607
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  • 3
    Electronic Resource
    Electronic Resource
    Theoretical studies on the intramolecular cyclization of alkyl halide anions (1990)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Computational Chemistry 11 (1990), S. 1119-1124 
    Details
    ISSN: 0192-8651
    Keywords: Computational Chemistry and Molecular Modeling ; Biochemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Computer Science
    Notes: The intramolecular cyclization reactions of alkyl fluoride and chloride anions1 were investigated theoretically using the AM1 method. Formation of five-membered ring was the most reactive and that of three-membered ring was the least reactive process in both series. For the fluoride series the reactivity order of n = 5 〉 6 〉 7 〉 4 〉 3 was dictated by the enthalpy (ΔH≠) effect while for the chloride series the entropy (ΔS≠) effect was found to play somewhat greater role due to the much better leaving ability of the chloride anion leading to the reactivity order of n = 5 〉 6 〉 4 〉 7 〉 3. For both series, BEP principle held and the degree of bond formation was greater with the fluoride series owing to the poor electron acceptor ability of the cleaving bond.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcc.540111002
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