Symmetry and Combinatorial Enumeration in Chemistry de Shinsaku Fujita

Symmetry and Combinatorial Enumeration in Chemistry

Shinsaku Fujita

This book is written to introduce a new approach to stereochemical problems and to combinatorial enumerations in chemistry. This approach is based on group the ory, but different from conventional ways adopted by most textbooks on chemical group theory. The difference sterns from their starting points: conjugate subgroups and conjugacy classes. The conventional textbooks deal with linear representations and character ta bles of point groups. This fact implies that they lay stress on conjugacy classesj in fact, such group characters are determined for the respective conjugacy classes. This approach is versatile, since conjugacy classes can be easily obtained by ex amining every element of a group. It is unnecessary to know the group-subgroup relationship of the group, which is not always easy to obtain. The same situa tion is true for chemical enumerations, though these are founded on permutation groups. Thus, the P6lya-Redfield theorem (1935 and 1927) uses a cycle index that is composed of terms associated with conjugacy classes.

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Cuprins

1 Introduction.- 2 Symmetry and Point Groups.- 2.1 Symmetry Operations and Elements.- 2.2 Conjugacy Glasses in Point Groups.- 2.3 Subgroups of Point Groups.- 2.4 Conjugate and Normal Subgroups of Point Groups.- 2.5 Non-Redundant Set of Subgroups for a Point Group.- 3 Permutation Groups.- 3.1 Permutations and Cycles.- 3.2 Permutation Groups.- 3.3 Transitivity and Orbits..- 3.4 Symmetric Groups.- 3.5 Parity.- 3.6 Alternating Groups.- 4 Axioms and Theorems of Group Theory.- 4.1 Axioms and Multiplication Tables.- 4.2 Subgroups.- 4.3 Cosets.- 4.4 Equivalence Relations.- 4.5 Conjugacy Classes.- 4.6 Conjugate and Normal Subgroups.- 4.7 Subgroup Lattices.- 4.8 Cyclic Groups.- 5 Coset Representations and Orbits.- 5.1 Coset Representations.- 5.2 Transitive Permutation Representations.- 5.3 Mark Tables.- 5.4 Permutation Representations and Orbits.- 6 Systematic Classification of Molecular Symmetries.- 6.1 Assignment of Coset Representations to Orbits.- 6.2 SCR Notation.- 7 Local Symmetries and Forbidden Coset Representations.- 7.1 Blocks and Local Symmetries.- 7.2 Forbidden Coset Representations.- 8 Chirality Fittingness of an Orbit.- 8.1 Ligands.- 8.2 Behavior of Cosets on the Action of a CR.- 8.3 Chirality Fittingness of an Orbit.- 9 Subduction of Coset Representations.- 9.1 Subduction of Coset Representations.- 9.2 Subduced Mark Table.- 9.3 Chemical Meaning of Subduction.- 9.4 Unit Subduced Cycle Indices.- 9.5 Unit Subduced Cycle Indices with Chirality Fittingness.- 9.6 Desymmetrization Lattice.- 10 Prochirality.- 10.1 Desymmetrization of Enantiospheric Orbits.- 10.2 Prochirality.- 10.3 Further Desymmetrization of Enantiospheric Orbits.- 10.4 Chiral syntheses.- 11 Desymmetrization of Para-Achiral Compounds.- 11.1 Chiral Subduction of Homospheric Orbits.- 11.2 Desymmetrization of Homospheric Orbits.- 11.3 Chemoselective and Stereoselective Processes.- 12 Topicity and Stereogenicity.- 12.1 Topicity Based On Chirality Fittingness of an Orbit.- 12.2 Stereogenicity.- 13 Counting Orbits.- 13.1 The Cauchy-Frobenius Lemma.- 13.2 Configurations.- 13.3 The Pólya-Redfield Theorem.- 14 Obligatory Minimum Valencies.- 14.1 Isomer Enumeration under the OMV Restriction.- 14.2 Unit Cycle Indices.- 15 Compounds with Achiral Ligands Only.- 15.1 Compounds with Given Symmetries.- 15.2 Compounds with Given Symmetries and Weight.- 16 New Cycle Index.- 16.1 New Cycle Indices Based On USCIs.- 16.2 Correlation of New Cycle Indices to Pólya’s Theorem.- 16.3 Partial Cycle Indices.- 17 Cage-Shaped Molecules with High Symmetries.- 17.1 Edge Strategy.- 17.2 Tricyclodecanes with Td and Its Subsymmetries.- 17.3 Use of Another Ligand-Inventory.- 17.4 New Type of Cycle Index.- 18 Elementary Superposition.- 18.1 The USCI Approach.- 18.2 Elementary Superposition.- 18.3 Superposition for Other Indices.- 19 Compounds with Achiral and Chiral Ligands.- 19.1 Compounds with Given Symmetries.- 19.2 Compounds with Given Symmetries and Weights.- 19.3 Compounds with Given Weights.- 19.4 Special Cases.- 19.5 Other Indices.- 20 Compounds with Rotatable Ligands.- 20.1 Rigid Skeleton and Rotatable Ligands.- 20.2 Enumeration of Rotatable Ligands.- 20.3 Enumeration of Non-Rigid Isomers.- 20.4 Total Numbers.- 20.5 Typical Procedure for Enumeration.- 21 Promolecules.- 21.1 Molecular Models.- 21.2 Proligands and Promolecules.- 21.3 Enumeration of Promolecules.- 21.4 Molecules Based on Promolecules.- 21.5 Prochiralities of Promolecules and Molecules.- 21.6 Concluding Remarks.- 22 Appendix A. Mark Tables.- A.1 Td Point Group and Its Subgroups.- A. 2 D3h Point Group and Its Subgroups.- 23Appendix B. Inverses of Mark Tables.- B. 1 Td Point Group and Its Subgroups.- B. 2 D3h Point Group and Its Subgroups.- 24 Appendix C. Subduction Tables.- C. 1 Td Point Group and Its Subgroups.- C. 2 D3h Point Group and Its Subgroups.- 25 Appendix D. Tables of USCIs.- D. 1 Td Point Group and Its Subgroups.- D. 2 D3h Point Group and Its Subgroups.- 26 Appendix E. Tables of USCI-CFs.- E. 1 Td Point Group and Its Subgroups.- E.2 D3h Point Group and Its Subgroups.- 27 Index.