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  • 1
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    The @journal of organic chemistry 29 (1964), S. 1035-1037 
    ISSN: 1520-6904
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    The @journal of organic chemistry 29 (1964), S. 1038-1041 
    ISSN: 1520-6904
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Theoretical chemistry accounts 29 (1973), S. 313-317 
    ISSN: 1432-2234
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung SCF-Rechnungen unter Benutzung aller Valenzelektronen stützen die lineare “sesquiacetylen”-ähnliche Geometrie in Propargyldianionen. Die beiden zugehörigen Kationen befinden sich in der Nähe des zentralen Kohlenstoffatoms und bilden einen MC2M-Winkel von 90°. Die Wanderung des Lithiums in allylartigen Systemen wird als intramolekulare sigmatrope Umlagerung interpretiert.
    Abstract: Résumé Des calculs SCF pour tous les électrons de valence sont en faveur de la géométrie linéaire «sesquiacétylénique» dans les dianions propargyliques. Les deux cations univalents correspondants sont proches du carbone central avec un angle MC2M de 90°. La migration du lithium dans les systèmes allyliques est interprétée comme un réarrangement intramoléculaire sigmatrope.
    Notes: Abstract All-valence-electron SCF calculations support the linear “sesquiacetylenic” geometry in propargylic dianions. The two accompanying univalent cations are close to the central carbon, with an angle MC2M of 90°. The migration of lithium in allylic systems is interpreted as an intramolecular sigmatropic rearrangement.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Structural chemistry 1 (1990), S. 265-279 
    ISSN: 1572-9001
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract This contribution examines the size and shape of aromatic organic molecules against a background of existing concepts of molecular size and shape, and against a background of data for aliphatics. It is therefore partly a review and partly an analysis of new computational results. It is stressed that the notion of shape can be-and has been-detached from the notion of size, that the notion of size can be-and has been-detached from the notion of shape, but also that the two can be and have been wedded to advantage. A substantial amount of new material is presented, discussion concentrating on molecular volumes, surface areas, cross-sectional areas, average free volumes in the bulk, and packing densities. A distinction is made between the bare and the expanded molecular bodies. It is concluded that attributes of the first type of body work better in correlations, while attributes of the second are closer to experimental measures of size.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Computational Chemistry 1 (1980), S. 111-117 
    ISSN: 0192-8651
    Keywords: Computational Chemistry and Molecular Modeling ; Biochemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Computer Science
    Notes: A molecular mechanical force field for fluorinated ethylenes and propylenes is described. The field computes geometries, dipole moments, and energy differences between isomers and rotamers. Component analysis indicates that “classical” strains alone (skeletal, nonbonded, electrostatic) cannot account for energy relationships. The discussion is supplemented by a semiempirical quantum chemical comparison of cis- and trans-FCH=CHF and of gauche- and anti-FCH2CH2F.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Computational Chemistry 5 (1984), S. 299-306 
    ISSN: 0192-8651
    Keywords: Computational Chemistry and Molecular Modeling ; Biochemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Computer Science
    Notes: Molecular mechanical calculations for hetero-substituted hydrocarbons present certain difficulties that are not encountered in dealing with hydrocarbons. Ways are proposed to overcome such difficulties, sometimes by two-step or iterative computation. The following topics are considered: fitting the force field by using data from studies in solution; ways to estimate atomic charges or, alternatively, bond moments; ways to account for field effects upon atomic charges and bond moments.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Computational Chemistry 6 (1985), S. 1-4 
    ISSN: 0192-8651
    Keywords: Computational Chemistry and Molecular Modeling ; Biochemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Computer Science
    Notes: It is noticed that inclusion of an electrostatic term in the molecular-mechanical treatment of hydrocarbons would compel the nonbonding parameters of different force fields to become more alike than they are at present. Apart from removing the discontinuity in passing from the calculation of an unfunctionalized parent compound to the calculation of its functionalized derivatives, it is expected that the inclusion would improve results for the hydrocarbons themselves.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Computational Chemistry 2 (1981), S. 384-391 
    ISSN: 0192-8651
    Keywords: Computational Chemistry and Molecular Modeling ; Biochemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Computer Science
    Notes: With a view of using data on solutions and liquids for parameter fitting in molecular mechanical force fields, Abraham's theory of solvation is incorporated in the force field procedure. Geometries and bond moments are estimated internally, partial account being taken of bond-bond induction, and used to calculate the intramolecular electrostatic energy, dipole moment, and the dipole and quadrupole terms in the solvation energy. Three dielectric constants are used, one for the solute in the vapor, one for the solution, and one for the intramolecular space through which dipole-dipole interactions take place. Examples are given, including such where computation differs with measurement, to illustrate the performance of the scheme.
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Computational Chemistry 7 (1986), S. 144-152 
    ISSN: 0192-8651
    Keywords: Computational Chemistry and Molecular Modeling ; Biochemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Computer Science
    Notes: A nonanalytical procedure is proposed to calculate the surface area and cross-sectional areas of molecules. Results are reviewed for about 70 species comprising alkanes, acyclic and cyclic, alkyl halides, and alcohols. By regression analysis, relationships are detected between surface areas or segment areas and physical properties. Computed cross-sectional areas are confronted with adsorption values. Four ways are proposed to define quantitatively the intuitive notion of «molecular globularity».
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Computational Chemistry 9 (1988), S. 18-24 
    ISSN: 0192-8651
    Keywords: Computational Chemistry and Molecular Modeling ; Biochemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Computer Science
    Notes: This article examines the numerical estimation of molecular surface areas within the model of overlapping atomic spheres. One has the choice of either basing the estimate on all elements that contribute to the surface, or of ignoring systematically some elements in the interatomic clefts. It is argued that the second choice, even though more approximate, implicitly improves on the model and is to be preferred. Since surface areas are not measurable, the demonstration is unavoidably roundabout, relying mostly on correlation analysis. Among the regressors occur two compounded parameters. One, ratio of the surface area of the equivalent sphere to the surface area, is interpreted as a measure of molecular globularity. It reflects the molecular axis-ratio and surface convolution. The other, ratio of the surface area to the volume, is interpreted as a measure of the global congestion of a chemical residue. Together with a measure of the local congestion at the point of attachment, it affects the steric hindrance that a residue offers. The relation between the surface area and the number of valence electrons is also discussed.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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