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  • 1
    Electronic Resource
    Electronic Resource
    Anab initio investigation of rotation and inversion barriers in formylphosphine (1980)
    Springer
    Monatshefte für Chemie 111 (1980), S. 213-220 
    Details
    ISSN: 1434-4475
    Keywords: Acylphosphines ; Formylphosphine ; Inversion barrier ; Rotation barrier
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Die Rotation um N−CO-Bindungen in Amiden wurde bisher intensiv untersucht, eine entsprechende Rotationsbarriere für Drehungen um die P−CO-Bindung in Acylphosphinen wurde jedoch nicht beobachtet. Eine 4-31Gab initio-Untersuchung an Formylphosphin ergibt Rotationsbarrieren von 9,6 und 13,5 kJ mol−1 und eine pyramidale Inversionsbarriere von 108,0 kJ mol−1 als Voraussage. Ein Vergleich der STO-3G und STO-3G* Barrieren legt nahe, daß Polarisationsfunktionen für die Beschreibung der Rotation in diesen Systemen nicht nötig sind.
    Notes: Abstract Rotation about N−CO bonds in amides has been extensively investigated, but a corresponding barrier to rotation about the P−CO bond in an acylphosphine has yet to be observed. In the present 4-31Gab initio study of formylphosphine, rotation barriers of 9.6 and 13.5 kJ mol−1 and a phosphorus pyramidal inversion barrier of 108.0 kJ mol−1 are predicted. A comparison of STO-3G and STO-3G* barriers suggests that polarization functions are not needed to describe rotation in this system.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00938729
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  • 2
    Electronic Resource
    Electronic Resource
    On chiral pathways inE n : A dimensional analysis (1997)
    Springer
    Theoretical chemistry accounts 95 (1997), S. 63-65 
    Details
    ISSN: 1432-2234
    Keywords: Chirality ; Chiral pathways ; Homochirality
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A dimensional analysis shows that all chiral labeled and unlabeled simplexes inE 2 and all maximally labeled simplexes in higher dimensions, are unique in that they can be partitioned into disjoint heterochiral sets. Such partition is impossible for all other labeled and unlabeledm-point sets (m ⩾n + 2) inE n , since they and their enantiomorphs are chirally connected.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02341691
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  • 3
    Electronic Resource
    Electronic Resource
    Book reviews (1991)
    Springer
    Structural chemistry 2 (1991), S. 661-665 
    Details
    ISSN: 1572-9001
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00676829
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  • 4
    Electronic Resource
    Electronic Resource
    Book reviews (1992)
    Springer
    Structural chemistry 3 (1992), S. 67-71 
    Details
    ISSN: 1572-9001
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00671982
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  • 5
    Electronic Resource
    Electronic Resource
    An ab initio investigation into the SN2 reaction: Frontside attack versus backside attack in the reaction of F− with CH3F (1977)
    Springer
    Theoretical chemistry accounts 44 (1977), S. 245-256 
    Details
    ISSN: 1432-2234
    Keywords: SN2 reaction, frontside versus backside attack ; CH3F 2 − ; Geometry optimization, force method
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The energy hypersurface for the attack of fluoride ion on methyl fluoride has been explored with ab initio LCAO-SCF calculations at a split-valence basis set level. Transition states for frontside and backside attack have been located. In addition to transition states, two possible F−-CH3F clusters have been identified. The transition state for the substitution of fluoride with retention of configuration is found to be 56 kcal/mol higher than the transition state for inversion of configuration. The transition state for hydride displacement with inversion is 62 kcal/mol above the transition state for fluoride substitution with inversion.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00551167
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  • 6
    Electronic Resource
    Electronic Resource
    Shape space of achiral simplexes (1993)
    Springer
    Journal of mathematical chemistry 13 (1993), S. 209-211 
    Details
    ISSN: 1572-8897
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mathematics
    Notes: Abstract We examine the general dimensional relation between the shape space of then-simplexes and the subspace of their achiral sets. It is found that the only simplexes that can be partitioned into “left-handed” and “right-handed” classes are the triangles in Euclidean 2-space.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01165566
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  • 7
    Electronic Resource
    Electronic Resource
    A unification of chirality measures (1995)
    Springer
    Journal of mathematical chemistry 17 (1995), S. 35-53 
    Details
    ISSN: 1572-8897
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mathematics
    Notes: Abstract A general classification of chirality measures is suggested, based on a new unifying scheme. Two classes of measures - congruity and resolution type — are defined All chirality measures so far reported in the literature are found to belong to one of these two classes. At a higher level of unification, a more general construction is suggested that includes congruity and resolution measures as limiting cases. It is shown that congruity measures are nested in clusters of eight, generated by 23 combinations of their possible choice of a reference object (chiral vs. achiral), representation form (optimized vs. factorized) and type of chiral object under consideration (discrete vs. continuous). Each of the eight cases can have an infinite number of variations depending on the choice of averaging scheme. The problem of dimensionality is discussed for congruity measures and is shown to be unresolvable only for the case of chirality measures based on the discrete metric (e.g. overlap measures).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01165136
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  • 8
    Electronic Resource
    Electronic Resource
    Specification of chirality for links and knots (1996)
    Springer
    Journal of mathematical chemistry 19 (1996), S. 241-263 
    Details
    ISSN: 1572-8897
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mathematics
    Notes: Abstract A general scheme has been developed for the assignment of chirality descriptors to chiral links and knots. For oriented links and knots, the new D/L scheme employs linking numbers, self-writhes, and writhe profiles, in descending hierarchical order, with self-writhes and writhe profiles limited to alternating links and knots. A related scheme applies to non-oriented links and knots. In a modification of a previous scheme, the use of vertex-bicolored digraphs is introduced in order to compute writhe profiles of oriented links and knots. It is pointed out that even though the different geometric presentations of each individual chiral knot or link can be partitioned into homochirality classes, the links and knots that belong to a given configurational class, D or L, are not homochirally similar.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01166717
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  • 9
    Electronic Resource
    Electronic Resource
    Geometric chirality products (1991)
    Springer
    Journal of mathematical chemistry 6 (1991), S. 243-253 
    Details
    ISSN: 1572-8897
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mathematics
    Notes: Abstract Developed from Guye's “produit d'asymétrie” and formally similar to Ruch's chirality products, geometric chirality products are functions purely of molecular shape, without reference to chemical characteristics. In their normalized versions, geometric chirality products have all the attributes' of a chirality measure, i.e. they are similarity invariant and dimensionless in the interval [−1, 1]. An application to Boys' model of the tetrahedron is presented, and a detailed study of the results for triangular domains in E2 is reported. According to this measure, the most chiral triangle is infinitely flat and infinitely skewed. The analysis leads to the paradoxical conclusion that the most chiral triangle is infinitesimally close to an achiral one, The results are compared with those obtained for an overlap measure of chirality, and the relationship between molecular models and measures of chirality is briefly discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01192583
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  • 10
    Electronic Resource
    Electronic Resource
    A left-right classification of topologically chiral knots (1994)
    Springer
    Journal of mathematical chemistry 15 (1994), S. 35-62 
    Details
    ISSN: 1572-8897
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mathematics
    Notes: Abstract A method for partitioning topologically chiral knots into mutually heterochiral classes has been developed, based on the principle that for such knots there exist no diagrams whose vertex-bicolored graphs are composed of equivalent black and white subgraphs. The method, which introduces the concept ofwrithe profiles, is successfully applied to alternating as well as non-alternating prime and composite knots, and works in cases where the Jones and Kauffman polynomials fail to recognize the knot's chirality. It is shown that writhe profiles are sensitive indicators of diagram similarity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01277547
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