ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Physical Chemistry  (64)
  • Wiley-Blackwell  (64)
  • American Institute of Physics (AIP)
  • 1985-1989  (64)
  • 1950-1954
  • 1925-1929
  • 1
    Electronic Resource
    Electronic Resource
    Gas phase reactivities of isomeric ions: Methylenediphenylcyclopropane and diphenylmethylenecyclopropane (1989)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 2 (1989), S. 117-130 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Gas phase ion/molecule reactions have been used to probe the structure of ions obtained by electron impact upon 1-(diphenylmethylene)cyclopropane and 2,2-diphenyl-1-methylenecyclopropane. The resulting ions of molecular composition C16H14 (m/z 206+) were reacted with charge transfer reagents (6·9 〈 IP 〈 8·8eV), giving evidence for the presence of isomeric ions with different reactivities. The less reactive ion is identified as a trimethylenemethane species (TMM+) in which one cyclopropane bond is broken; the more reactive ions are assigned as vertical ions in which the cyclopropane ring is unaffected. The vertical ions have recombination energies of 8·44 ± 0·05eV, whereas TMM+ has one of 7·41±0·05eV. The TMM+ fraction is not constant; it increases with increasing IP of the reagent. This is attributed to a reagent-catalyzed isomerization of the vertical ion to TMM+. In addition, the reagent ions are observed to undergo a unique reaction with the neutral methylenecyclopropane derivatives: electron transfer and ring opening to yield TMM+. These findings limit the application of the customary equilibrium measurements as a method to determine the substrate IP.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610020205
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    A kinetics study of the reaction of Cl with NO2This work was supported by a NASA contract. The results were presented at the 13th Informal Conference on Photochemistry, Clear Water Beach, Florida, January 4-7, 1978. (1988)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 20 (1988), S. 811-814 
    Details
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The third order rate coefficients for the addition reaction of Cl with NO2, Cl + NO2 + M → ClNO2 (ClONO) + M; k1, were measured to be k1(He) = (7.5 ± 1.1) × 10-31 cm6 molecule-2 s-1 and k1(N2) = (16.6 ± 3.0) × 10-31 cm6 molecule-2 s-1 at 298 K using the flash photolysis-resonance fluorescence method. The pressure range of the study was 15 to 500 torr He and 19 to 200 torr N2. The temperature dependence of the third order rate coefficients were also measured between 240 and 350 K. The 298 K results are compared with those from previous low pressure studies.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/kin.550201005
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Generation of ground electronic state haloalkyl radicals in the gas phase (1986)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 18 (1986), S. 639-649 
    Details
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Gaseous haloalkyl radicals were prepared by the photolysis of iodohaloalkanes in Pyrex vessels containing mercury (I) halides. Cleavage of the carbon-iodine bond gave mercury (II) halide and a radical which was subsequently shown to react on the ground state electronic energy surface. The usefulness of this method for chemical activation rate constant studies is illustrated by measurement of unimolecular rate constants for decomposition of CH2ClCH2Cl and CF3CH3. Possible mechanisms for photodecomposition of iodoalkanes in the presence of mercury (I) halides are discussed.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 4
    Electronic Resource
    Electronic Resource
    An FTIR spectroscopic study of the kinetics and mechanism for the NO2-initiated oxidation of tetramethyl ethylene at 298 K (1986)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 18 (1986), S. 1235-1247 
    Details
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The kinetics and mechansim for the NO2-initiated oxidation of tetramethyl ethylene (TME) have been studied using the FTIR spectroscopic method in mixtures containing NO2 and TME (0.1-1.0 Torr) and N2—O2 (700 Torr) at 298 ± 2 K. While TME decayed according to -d[TME]/dt = kobs[NO2][TME], NO2 exhibited a complex kinetic behavior. Furthermore, values of kobs were dependent on [O2]. Among the products were (CH3)2CO and at least three NO2-containing compounds. These results indicate the formation of a nitro-alkylperoxy radical via reactions (1), (-1), and (2), and its subsequent reactions leading to the observed products. The [O2]-dependence of kobs yielded k1 = (1.07 ± 0.15) × 10-20 cm3 molecule-1 S-1 and k-1/k2 = (3.54 ± 0.61) × 1018 molecule cm-3.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/kin.550181103
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Effect of cosolvent additives on relative rates of photooxidation on semiconductor surfaces (1988)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 1 (1988), S. 103-114 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The effect of solvent additives on the course of TiO2 photocatalyzed oxygenation of α-methylstyrene has been studied. While the addition of small amounts of nonhalogenated alcohols to TiO2 powders suspended in acetonitrile was found to decrease the rate of photooxygenation, added halogenated alcohols increase the rate of reaction. In addition, the solvent additives affect the observed product distribution.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610010206
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Theoretical study of pyrazole elimination of N-alkyl pyrazoles (1989)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 2 (1989), S. 225-231 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The gas-phase pyrazole elimination of N-alkyl pyrazoles has been studied using MNDO semi-empirical molecular orbital (MO) theory with complete geometry optimization of all stationary points. We found that the activation energies (Ea) of the concerted processes are around 80 kcal/mol, 25 Kcal/mol higher than experimental values. But the differences in Ea between compounds with different substituents are in good agreement with the experimental ones.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610020305
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Experimental determination of carbon vs. oxygen regioselectivity in reactions of gas-phase enolate ions (1989)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 2 (1989), S. 389-409 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A gas-phase experimental investigation of the competition between carbon and oxygen alkylation of a series of cyclic and acyclic enolate ions is described. Perfluoropropylene is shown to react in a characteristic way with oxyanions and carbanions to produce distinctive ionic products. The relative yields of these products formed in reactions with ambident enolate ions provides a measure of their intrinsic carbon vs. oxygen regioselectivity. The results for a series of enolates derived from aldehydes, ketones, esters, amides and related compounds show a wide range of reactivity which is a function of the nature of the central substituent. Most aldehyde and ketone enolates react mainly through oxygen, while enolates with σ-acceptor of π-donor type central substituents react mainly thorugh carbon. Ring-size in cyclic ketone enolates also influences C vs. O regioselectivity, i.e. small-ring enolates react mainly through carbon, while larger ring enolates (C7-C9) react preferentially through oxygen. The enolate reactivity patterns can be generally accounted for by the keto-enol energy differences for the parent carbonyl compounds, although some exceptions are evident. The origins of the highly variable, kinetically determined regioselectivities are discussed.
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610020505
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Dynamic isotope dilution kinetic study of the thermal conversions of bicyclo[3.2.0]hept-2-ene to bicyclo[2.2.1]hept-2-ene and to cyclopentadiene and ethene (1989)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 2 (1989), S. 455-466 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Mixtures of bicyclo[3.2.0]hept-2-ene and bicyclo[2.2.1]hept-2-ene, with one isomer labeled with two deuterium atoms, were isomerized in the gas phase at 276 °C. By following the concentration ratios of d0 and d2 versions of bicyclo[2.2.1]hept-2-ene as functions of time one finds that the partitioning of bicyclo[3.2.0]hept-2-ene between the primary products bicyclo[2.2.1]hept-2-ene and cyclopentadiene plus ethene is 2:1. This and earlier stereochemical results permit the calculation of the partitioning of the [3.2.0] olefin between the orbital symmetry allowed [1,3] carbon shift-with-inversion product and several forbidden or non-concerted reaction channels (approximately 1:1) and the stereochemistry of the ethene d2 formed from exo,exo-[6,7-2H2]bicyclo[3.2.0]hept-2-ene directly (1:1 E: Z).
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610020604
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Anionic nucleophile-cation radical combination reactions. The super-electrophilic properties of cation radicals in solution (1989)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 2 (1989), S. 580-584 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Rate constants were determined for the combination reactions of a series of cation radicals derived from substituted anthracenes with acetate, p-nitrobenzoate, trifluoroacetate, nitrate and perchlorate ions. Rate constants, depending on the identities of the cation radicals and the nucleophiles, ranging from about 200 to 2 × 1010 1 mol-1 s-1 were observed in acetonitrile at 293 K. The key steps in the reaction are (1) reversible complex formation between the anion and the cation radical followed by (2) irreversible bond formation \documentclass{article}\pagestyle{empty}\begin{document}$$ \begin{array}{*{20}c} {\rm{Ar}^{ + \cdot } + \rm{X}^ - \rightleftharpoons {{\rm{Ar}^{ + \cdot } } \mathord{\left/ {\vphantom {{\rm{Ar}^{ + \cdot } } {\rm{X}^ - }}} \right. \kern-\nulldelimiterspace} {\rm{X}^ - }}} &&&&& {(1)} \\ {{{\rm{Ar}^{ + \cdot } } \mathord{\left/ {\vphantom {{\rm{Ar}^{ + \cdot } } {\rm{X}^ - }}} \right. \kern-\nulldelimiterspace} {\rm{X}^ - }} \to \rm{Ar}^ \cdot - \rm{X}} &&&&& {(2)} \\ \end{array} $$\end{document}.The preliminary results show that cation radical-anionic nucleophile reactions can be very facile. The cation radicals of 9-nitro- and 9-cyanoanthracene are particularly reactive, giving rise to rate constants close to the diffusion-controlled limit with all anionic nucleophile studied and even react moderately rapidly with perchlorate ion. The reaction with perchlorate ion can be compared to the behavior of stable carbenium ions that coexist with the anion in solution and in crystalline salts.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610020711
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Comparative kinetic study of solvent effects in the reactions of 1,2-dinitrobenzene with butylamine and piperidine (1989)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 2 (1989), S. 631-645 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The kinetics of the aromatic nucleophilic substitution (SNAr) reactions of 1,2-dinitrobenzene (1,2-DNB) with butylamine (BA) and piperidine (PIP) were investigated as a function of the amine concentration and temperature, in chloroform, ethyl acetate, tetrahydrofuran (THF), acetonitrile (ACN), dimethylformamide (DMF), dimethyl sulphoxide (DMSO). benzene, toluene, chlorobenzene and diisopropyl ether.In the set of solvents consisting of ethyl acetate, THF, ACN, DMF and DMSO, neither reaction is catalysed (kA = k1). The sequence and range of reactivity for BA and PIP are similar in these solvents. These results indicate that reactions in which nitro in the leaving group behave differently from SNAr reactions with other leaving groups, such as halogens or alkoxy groups, since an intramolecular hydrogen bond may be expected between the leaving nitro group and the ammonium H of the nucleophiles. The correlations of the rate coefficients obtained with Taft and Kamlet's solvatochromic method support these conclusions.On the other hand, these reactions show mild acceleration with relatively non-polar solvents such as the aromatics and diisopropyl ether. The donor properties of these solvents and experiments with solvent mixtures suggest the formation of electron donor-acceptor complexes between them and 1,2-DNB. Hence the preferential solvation of 1,2-DNB by the donor solvent accounts for the mechanism observed.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610020806
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...