Library

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
  • 1
    Electronic Resource
    Electronic Resource
    Bond order orbitals and eigenvalues (1978)
    s.l. : American Chemical Society
    Journal of the American Chemical Society 100 (1978), S. 6581-6586 
    Details
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ja00489a007
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Mechanism of thermolysis of diketene in the gas phase (1978)
    s.l. : American Chemical Society
    The @journal of organic chemistry 43 (1978), S. 1146-1150 
    Details
    ISSN: 1520-6904
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/jo00400a026
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    A maximum bond order principle (1977)
    s.l. : American Chemical Society
    Journal of the American Chemical Society 99 (1977), S. 7800-7805 
    Details
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ja00466a009
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Mechanistic pathways for ketene dimerization (1975)
    Springer
    Theoretical chemistry accounts 40 (1975), S. 207-219 
    Details
    ISSN: 1432-2234
    Keywords: Ketene dimerization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A semiempirical MO method was used to calculate potential energy surfaces for ketene dimerization. One supra-supra and two supra-antara pathways were investigated. Six parameters were used to characterize the relative motion of individual groups. Two levels of approximation for the motion were considered. First, synchronous reaction pathways were followed, and a set of single-dimensional potential curves generated. Then, deviations from these synchronous reaction pathways were considered for each parameter and five two-dimensional potential surfaces for each pathway generated. Agreement with the available experimental data is satisfactory. However, we conclude that contrary to the Woodward-Hoffmann rules [1] the supra-supra pathway is allowed and the supra-antara pathways essentially forbidden. In the former case the local symmetry of the orbitals involved in the ring formation is not conserved during the reaction, in the latter case the nuclear repulsion is dominating.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00548455
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Comparative studies on a maximum bond order principle (1978)
    Springer
    Theoretical chemistry accounts 50 (1978), S. 1-10 
    Details
    ISSN: 1432-2234
    Keywords: Bond orders
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A recently proposed maximum bond order principle is studied with respect to choice of basis orbitals, choice of wavefunction and compared with other methods. Results for bond orders support the choice of Schmidt orthogonalized AO's with subsequent Löwdin orthogonalization. Differences between semiempirical andab initio wavefunctions in minimal basis sets usually have only minor effects on bond order values. For hydrocarbons bond order values are quite similar for Cohen's and this method. Finally, the dependence of bond orders on internal rotation and vibration is investigated in a few simple cases.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00552489
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Continuity of bond order (1979)
    Springer
    Theoretical chemistry accounts 51 (1979), S. 331-338 
    Details
    ISSN: 1432-2234
    Keywords: Bond order
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract To preserve the continuity of a recent bond order concept [1], the Mulliken overlap criterion for bonding and antibonding is replaced by a vector projection weighting procedure. The consequences of this change are discussed in applications to selected diatomics and polyatomics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00548941
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    A comparison between ethylene dimerization and Diels-Alder reaction (1979)
    Springer
    Theoretical chemistry accounts 52 (1979), S. 19-26 
    Details
    ISSN: 1432-2234
    Keywords: Cycloaddition reactions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The reaction pathways for the two reactions 2C2H4↔C4H8 and C2H4+C4H6↔ C6H10 were investigated. The transition state geometries and activation energies were determined with the SINDO method and compared. Both reactions were found concerted with different significance of diradical character at the transition state. Whereas the ethylene dimerization showed that a diradical will be encountered along the reaction pathway, we did not find one in the Diels-Alder reaction.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00581697
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Reaction pathways for various ketene dimers (1978)
    Springer
    Theoretical chemistry accounts 49 (1978), S. 249-257 
    Details
    ISSN: 1432-2234
    Keywords: Ketene dimers, thermolysis of ∼
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Alternative pathways for the thermolysis of diketene were investigated with a semiempirical SINDO method [1]. Transition states and activation energies for isomerization to cyclobutane-1,3-dione and 2,4-dimethylene-1,3-dioxetane were determined. The dissociation and formation of these three dimers into and from two ketenes was also calculated. The results disclose the possibility of existence of intermediates as well as the fragmentation into further products. Entropy appears as a major factor in this reaction at higher temperature.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00550035
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Charge distributions and multipole moments in molecules (1975)
    Springer
    Theoretical chemistry accounts 39 (1975), S. 301-312 
    Details
    ISSN: 1432-2234
    Keywords: Atomic charges ; Multipole moments
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The consideration of multipole moments is suggested as a new criterion for the validity of assignments of atomic charges in molecules. The total quadrupole and octupole moments generated by our definition of atomic charges are compared with the exact moments of the underlying wavefunction for various basis sets in selected diatomics. The analysis includes also total overlap and total dipole moment partitioning as well as 1σ MO overlap partitioning. All considerations together allow us to assess the validity of our charge definition as compared to Mulliken's and Löwdin's and the quality of the basis set.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00551541
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Mechanism of cyclopropane-propene isomerization (1976)
    Springer
    Theoretical chemistry accounts 42 (1976), S. 303-310 
    Details
    ISSN: 1432-2234
    Keywords: Cyclopropane-propene isomerization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A SINDO method was used to investigate the sequence of rearrangements in the cyclopropane-propene isomerization. Geometries of reactant and product were optimized for a complete set of 21 independent internal coordinates. Then the bond angle of the migrating H atom was chosen as reaction coordinate and all other geometrical parameters were energy minimized along this reaction coordinate. In the neighborhood of the transition state a Newton type iteration process is initiated to locate the transition state. The latter is characterized by a CCC bond angle close to 90 ° and an almost finished migration of the H atom. The activation energy was found about 25% lower than the experimental value of 65 kcal/mole. A sequence of rearrangements was established, suggesting the initiation of the reaction by a combination of two normal modes: a torsional vibration of the methylene groups together with an asymmetric stretch of the carbon framework. Our calculations classify the reaction as concerted.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00548472
    Library Location Call Number Volume/Issue/Year 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...