Pseudo-point-group approach to stereochemistry and stereoisomerism of cyclohexane derivatives

Fujita, Shinsaku

doi:10.2183/pjab.77.197

Cited by 3 publications

(2 citation statements)

References 6 publications

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“…The symmetry number is a measure of this property, and it is divided into internal and external contributions. The external symmetry is defined as the total number of equivalent positions a molecule can adopt, by rotations along axes, considering it as a rigid body. , On the other hand, the internal symmetry is related to rotations along bonds between atoms. The total symmetry number is defined according to eq…”

Section: Methodsmentioning

confidence: 99%

Graph-Based Method for the Automated Calculation of Thermochemical Properties of Components and Intermediate Species in the Hydroprocessing of Light Oil Fractions

Dávila

Martinis

2011

Ind. Eng. Chem. Res.

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A method based on graph theory has been formulated to estimate some key thermochemical properties commonly utilized in modeling acid-catalyzed transformations of hydrocarbons at the elementary step level. Presently, modeling techniques for these transformations frequently convey the computer-aided generation of reaction networks involving a very large number of molecules and intermediate species such as carbenium ions. Although quantum mechanical calculations have been widely used to estimate thermodynamic properties of carbenium ions accurately, the current performance of such techniques is yet insufficient for very large sets of species. The proposed method handles this problem by simply analyzing the connectivity of the carbon atoms within a molecule, which is less demanding from a computational point of view. Thus, it is possible to obtain information on the contributions from different structural groups and their indistinguishability, making property estimation straightforward. This work presents a set of rules for calculating the symmetry numbers of hydrocarbons with up to 2 rings, and Benson-like structural contribution groups for estimating the enthalpy of carbenium ions.

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Section: Methodsmentioning

confidence: 99%

Graph-Based Method for the Automated Calculation of Thermochemical Properties of Components and Intermediate Species in the Hydroprocessing of Light Oil Fractions

Dávila

Martinis

2011

Ind. Eng. Chem. Res.

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“…Strictly speaking, such a Haworth-projected skeleton should be replaced by two-chair forms of a cyclopropane skeleton. The interconversion between the two-chair forms has been discussed by proposing a pseudo-point group D 6h [29][30][31]. The twelve bridge positions of a superphane ([2 6 ](1,2,3,4,5,6)cyclophane) skeleton (3) can be replaced by divalent units, where resulting isomers are counted by the PCI (partial-cycle-index) method of the USCI approach [32].…”

Section: Previous Studies On D 6h -Skeletonsmentioning

confidence: 99%

Standard mark table and standard USCI-CF table of the point group D6h. Unification of candidates derived from different D6h-skeletons

Fujita¹

2021

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Combined-permutation representations (CPRs) for characterizing -skeletons (a benzene skeleton, a Haworth-projected skeleton, a superphane skeleton, and a coronene skeleton) are constructed by starting from respective sets of generators, where the permutation of each generator is combined with a mirror-permutation of 2-cycle to treat both achiral and chiral substituents under the GAP system. Thereby, the CPR of degree 8 (= 6 + 2) for the benzene skeleton, the CPR of degree 14 (= 12 + 2) for the Haworth-projected skeleton, the CPR of degree 14 (= 12 + 2) for the superphane skeleton, the CPR of degree 14 (= 12 + 2) for the coronene skeleton are generated to give primary mark tables (tables of marks) based on these CPRs. These primary mark tables generated by the GAP system are different in the sequence of subgroups from each other, although they stem from the same point group . They are unified into a single standard mark table by means of a newly-devised GAP function MarkTableforUSCI. Moreover, another newly-devised GAP function constructUSCITable is employed to construct a standard USCI-CF (unit-subduced-cycle-index-with-chirality-fittingness) table concordantly. After a set of PCI-CFs (partial cycle indices with chirality fittingness) is calculated for each skeleton, symmetry-itemized combinatorial enumeration is conducted by means of the PCI method of Fujita’s USCI approach (S. Fujita, Symmetry and Combinatorial Enumeration in Chemistry, Springer-Verlag, Berlin-Heidelberg, 1991).

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Conceptual defects of modern stereochemistry. Comprehensive remedy by stereoisograms based on RS-stereoisomerism for mediating between enantiomerism and stereoisomerism

Fujita¹

2017

Tetrahedron: Asymmetry

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Pseudo-point-group approach to stereochemistry and stereoisomerism of cyclohexane derivatives

Cited by 3 publications

References 6 publications

Graph-Based Method for the Automated Calculation of Thermochemical Properties of Components and Intermediate Species in the Hydroprocessing of Light Oil Fractions

Graph-Based Method for the Automated Calculation of Thermochemical Properties of Components and Intermediate Species in the Hydroprocessing of Light Oil Fractions

Standard mark table and standard USCI-CF table of the point group D6h. Unification of candidates derived from different D6h-skeletons

Conceptual defects of modern stereochemistry. Comprehensive remedy by stereoisograms based on RS-stereoisomerism for mediating between enantiomerism and stereoisomerism

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