Orbital Interactions in Chemistry, Second Edition

THOMAS A. ALBRIGHT, PhD, is Professor Emeritus in theDepartment of Chemistry at the University of Houston. He was aCamille and Henry Dreyfus Teacher-Scholar and an Alfred P. SloanResearch Fellow. He has been interested in exploring reactiondynamics in organometallic chemistry. The late JEREMY K. BURDETT, PhD, was Professor and Chairof the Chemistry Department at the University of Chicago. Dr.Burdett was awarded the Tilden Prize and Meldola Medal by the RoyalSociety of Chemistry. He was also a Camille and Henry DreyfusTeacher-Scholar and a Fellow of the John Guggenheim MemorialFoundation and Alfred P. Sloan Foundation. MYUNG-HWAN WHANGBO, PhD, is Distinguished Professor inthe Chemistry Department of North Carolina State University. He hasbeen awarded the Camille and Henry Dreyfus Fellowship, theAlexander von Humboldt Research Award to Senior Scientists, theHo-Am Prize in Science, and Docteur Honoris Causa from Universit deNantes.

1. ATOMIC AND MOLECULAR ORBITALS 1.1. Introduction, 1.2. Atomic Orbitals, 1.3. Molecular Orbitals, 2. CONCEPTS OF BONDING AND ORBITAL INTERACTION 2.1. Orbital Interaction Energy, A. Degenerate Interaction, B. Nondegenerate Interaction, 2.2. Molecular Orbital Coefficients, A. Degenerate Interaction, B. Nondegenerate Interaction, 2.3. The Two Orbital Problem -- Summary, 2.4. Electron Density Distribution, 3. PERTURBATIONAL MOLECULAR ORBITAL THEORY 3.1. Introduction, 3.2. Intermolecular Perturbation, 3.3. Linear H3, HF and theThree Orbital Problem, 3.4. Degenerate Perturbation, 4. SYMMETRY CONSIDERATIONS 4.1. Introduction, 4.2. Symmetry of Molecules, 4.3. Representations of Groups, 4.4. Symmetry Properties of Orbitals, 4.5. Symmetry-Adapted Wavefunctions, 4.6. Direct Products, 4.7. Symmetry Properties, Integrals and the Noncrossing Rule, 4.8. Principles of Orbital Construction Using Symmetry Principles, 4.9. Symmetry Properties of Molecular Vibrations, 5. MOLECULAR ORBITAL CONSTRUCTION FROM FRAGMENT ORBITALS 5.1. Introduction, 5.2. Triangular H3, 5.3. Rectangular and Square Planar H4, 5.4. Tetrahedral H4, 5.5. Linear H4, 5.6. Pentagonal H5 and Hexagonal H6, 5.7. Orbitals of ?a Systems, 6. MOLECULAR ORBITALS OF DIATOMIC MOLECULES AND ELECTRONEGATIVITY PERTURBATION 6.1. Introduction, 6.2. Orbital Hybridization, 6.3. Molecular Orbitals of Diatomic Molecules, 6.4. Electronegativity Perturbation, 6.5. Photoelectron Spectroscopy, 7. MOLECULAR ORBITALS AND GEOMETRICAL PERTURBATIONS 7.1. Molecular Orbitals of AH2, 7.2. Geometrical Perturbation, 7.3. Walsh Diagrams, 7.4. Jahn-Teller Distortions, A. First-Order Jahn-Teller Distortion, B. Second-Order Jahn-Teller Distortion, C. Three-Center Bonding, 7.5. Bond Orbitals and PE Spectra of AH2 Molecules, 8. STATE WAVEFUNCTIONS AND STATE ENERGIES 8.1. Introduction, 8.2. The Molecular Hamiltonian and State Wavefunctions, 8.3. The Fock Operator, 8.4. State Energy, 8.5. Excitation Energy, 8.6. Ionization Potential and Electron Affinity, 8.7. Electron Density Distribution and the Magnitudes of Coulomb and Exchange Repulsions, 8.8. Low vs. High Spin States, 8.9. Electron-Electron Repulsion and Charged Species, 8.10. Configuration Interaction, 8.11. The LDA Approach, 9. MOLECULAR ORBITALS OF SMALL BUILDING BLOCKS 9.l. Introduction, 9.2. The AH System, 9.3. Shapes of AH3 Systems, 9.4. ?a-Bonding Effects of Ligands, 9.5. The AH4 System, 9.6. The AHn Series -- Some Generalizations, 10. MOLECULES WITH TWO HEAVY ATOMS 10.1. Introduction, 10.2. A2H6 Systems, 10.3. Twelve-Electron A2H4 Systems, A. Sudden Polarization, B. Substituent Effects, C. Dimerization of AH2 and Pyramidalization of A2H4, 10.4. Fourteen-Electron AH2BH2 Systems, l0.5. AH3BH2 Systems, 10.6. AH3BH Systems, 11. ORBITAL INTERACTIONS THROUGH SPACE AND THROUGH BONDS 11.l. Introduction, 11.2. In-Plane o Orbitals of Small Rings, A. Cyclopropane, B. Cyclobutane, 11.3. Through-Bond Interactions, A. The Nature of Through-Bond Coupling, B. Other Through-Bond Coupling Units, 11.4. Breaking a C-C Bond, 12. POLYENES AND CONJUGATED SYSTEMS 12.1. Acylic Polyenes, 12.2. Huckel Theory, 12.3. Cyclic Systems, 12.4. Cross-Conjugated Polyenes, 12.5. Perturbations of Cyclic Systems, 12.6. Conjugation in Three Dimensions, 13. SOLIDS 13.1. Energy Bands, 13.2. Distortions of One-Dimensional Systems, 13.3. Other One-Dimensional Systems, 13.4. Two and Three-Dimensional Systems, 13.5. Electron Counting and Structure, 13.6. High Spin and Low Spin Considerations, 14. HYPERVALENT MOLECULES 14.1. Orbitals of Octahedrally Based Molecules, 14.2. Solid State Hypervalent Compounds, 14.3. Geometries of Hypervalent Molecules, 15. TRANSITION METAL COMPLEXES--A STARTING POINT AT THE OCTAHEDRON 15.l. Introduction, 15.2. Octahedral ML6, 15.3. ?a-Effects in an Octahedron, 15.4. Distortions from Octahedral Geometry, 15.5. Octahedral Solids, 16. SQUARE PLANAR, TETRAHEDRAL ML4 COMPLEXES AND ELECTRON COUNTING 16.1. Introduction, 16.2. The Square Planar ML4 Molecule, 16.3. Electron Counting, 16.4. The Square Planar - Tetrahedral ML4 Interconversion, 16.5. The Solid State, 17. FIVE COORDINATION 17.1. Introduction, 17.2. The C4V ML5 Fragment, 17.3. Five Coordination, 17.4. Molecules Built up from ML5 Fragments, 17.5. Pentacoordinate Nitrosyls, 17.6. Square Pyramids in the Solid State, 18. THE C2v ML3 FRAGMENT 18.1. Introduction, 18.2. The Orbitals of a C2v ML3 Fragment, 18.3. ML3-Containing Metallocycles, 18.4. Comparison of C2V ML3 and C4v ML5 Fragments, 19. THE ML2 AND ML4 FRAGMENTS 19.l. Development of the C2V ML4 Fragment Orbitals, 19.2. The Fe(CO)4 Story, 19.3. Olefin-ML4 Complexes and M2L8 Dimers, 19.4. The C2v ML2 Fragment, 19.5. Polyene-ML2 Complexes, 19.6. Reductive Elimination and Oxidative Addition, 20. COMPLEXES OF ML3, MCp, AND Cp2M 20.1. Derivation of the Orbitals for a C3V ML3 Fragment, 20.2. The CpM Fragment Orbitals, 20.3. Cp2M and Metallocenes, 20.4. Cp2MLn Complexes, 21. THE ISOLOBAL ANALOGY 21.1. Introduction, 21.2. Generation of Isolobal Fragments, 21.3. Caveats, 21.4. Illustrations of the Isolobal Analogy, 21.5. Reactions, 21.6. Extensions, 22. CLUSTER COMPOUNDS 22.1. Types of Cluster Compounds, 22.2. Cluster Orbitals, 22.3. Wade's Rules, 22.4. Violations, 22.5. Extensions, 23. CHEMISTRY ON THE SURFACE 23.1. Introduction, 23.2. General Structural Considerations, 23.3. General Considerations of Adsorption on Surfaces, 23.4. Diatomics on a Surface, 23.5. The Surface of Semiconductors, 24. Magnetic Properties 24.1. Introduction 24.2. The Magnetic Insulating State A. Electronic Structures B. Factors Affecting the Effective On-site Repulsion C. Effect of Spin Arrangement On the Band Gap 24.3. Properties Associated With the Magnetic Moment A. The Magnetic Moment B. Magnetization C. Magnetic Susceptibility D. Experimental Investigation of Magnetic Energy Levels 24.4. Symmetric Spin Exchange A. Mapping Analysis For a Spin Dimer B. Through-space and Through-bond Orbital Interactions Leading To Spin Exchange C. Mapping Analysis Based On Broken-symmetry States 24.5. Magnetic Structure A. Spin Frustration and Non-collinear Spin Arrangement B. Long-range Antiferromagnetic Order C. Ferromagnetic and Ferromagnetic-like Transitions D. Typical Cases Leading to Ferromagnetic Interaction E. Short Range Order 24.6. The Energy Gap in the Magnetic Energy Spectrum A. Spin Gap and Field-induced Magnetic Order B. Magnetization Plateaus 24.7. Spin-orbit Coupling A. Spin Orientation B. Single-ion Anisotropy C. Uniaxial Magnetism vs. Jahn-Teller Instability D. The Dzyaloshinskii-Moriya (DM) Interaction E. Singlet-triplet Mixing Under Spin-orbit Coupling 24.8. What Appears Versus What Is A. Idle Spin In Cu3(OH)4SO4? B. The FM-AFM Versus AFM-AFM Chain? C. Diamond Chains? D. Spin Gap Behavior of a 2D Square Net? 24.9. Model Hamiltonians Beyond the Level of Spin Exchange 24.10. Summary Remarks Appendix I. Perturbational Molecular Orbital Theory Appendix II. Some Common Group Tables Appendix III. Normal Modes for Some Common Structural Types INDEX