Electronic Structure and Properties of Transition Metal Compounds: Theory and Applications

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Electronic Structure and Properties of Transition Metal Compounds: Theory and Applications
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Contents
Preface to the Third Edition
Extract from the Preface to the Second Edition
Extract from the Preface to the First Edition
Foreword to the First Edition
Mathematical Symbols
Abbreviations
1. Introduction: Subject and Methods
	1.1 Objectives
		1.1.1 Molecular Engineering and Intuitive Guesswork
		1.1.2 Main Objectives of This Book in Comparison with Other Sources
	1.2 Definitions of Chemical Bonding and Transition Metal Coordination System
		1.2.1 Chemical Bonding as an Electronic Phenomenon
		1.2.2 Definition of Coordination System
	1.3 The Schrödinger Equation
		1.3.1 Formulation
		1.3.2 Role of Approximations
	Summary Notes
	References
2. Atomic States
	2.1 One-Electron States
		2.1.1 Angular and Radial Functions
		2.1.2 Orbital Overlaps: Hybridized Functions
		2.1.3 Spin–Orbital Interaction
		2.1.4 Relativistic Atomic Functions
	2.2 Multielectron States: Energy Terms
		2.2.1 Electronic Configurations and Terms
		2.2.2 Multielectron Wavefunctions
		2.2.3 Slater-Condon and Racah Parameters
		2.2.4 The Hartree–Fock Method
	Summary Notes
	Questions
	Exercises and Problems
	References
3. Symmetry Ideas and Group-Theoretical Description
	3.1 Symmetry Transformations and Matrices
	3.2 Groups of Symmetry Transformations
	3.3 Classification of Point Groups
		Example 3.1. The Symmetry Group of an Octahedral Oh System and Its Classes
	3.4 Representations of Groups and Matrices of Representations
		Example 3.2. The Rules of IrReps and Characters in C4v Point Group
	3.5 Classification of Molecular Terms and Vibrations, Selection Rules, and The Wigner–Eckart Theorem
		Example 3.3. Energy Terms of Electronic Configuration e2
	3.6 Construction of Symmetrized Molecular Orbitals and Normal Vibrations
		Example 3.4. Construction of Eg-Symmetry-Adapted s MOs for Octahedral Oh Systems
		Example 3.5. Construction of T2g-Symmetry-Adapted p MOs for Octahedral Oh Systems
		Example 3.6. Normal Coordinates of a Regular Triangular Molecule X3
	3.7 The Notion of Double Groups
	Summary Notes
	Exercises and Problems
	References
4. Crystal Field Theory
	4.1 Introduction
		4.1.1 Brief History
		4.1.2 Main Assumptions
	4.2 Splitting of the Energy Levels of One d Electron in Ligand Fields
		4.2.1 Qualitative Aspects and Visual Interpretation
		4.2.2 Calculation of the Splitting Magnitude
			Example 4.1. Splitting of a d-Electron Term in Octahedral Crystal Fields
		4.2.3 Group-Theoretical Analysis
	4.3 Several d Electrons
		4.3.1 Case of a Weak Field
		4.3.2 Strong Crystal Fields and Low- and High-Spin Complexes
			Example 4.2. High-Spin and Low-Spin Octahedral Complexes of Iron
		4.3.3 Energy Terms of Strong-Field Configurations
		4.3.4 Arbitrary Ligand Fields and Tanabe–Sugano Diagrams
	4.4 f-Electron Term Splitting
	4.5 Crystal Field Parameters and Extrastabilization Energy
	4.6 Limits of Applicability of Crystal Field Theory
	Summary Notes
	Questions
	Exercises and Problems
	References
5. Molecular Orbitals and Related Description of Electronic Structure
	5.1 Basic Ideas of the MO LCAO Method
		5.1.1 Main Assumptions
		5.1.2 Secular Equation
		5.1.3 Classification by Symmetry
		5.1.4 Symmetrized Orbitals
		5.1.5 Simplification of the Secular Equation
		5.1.6 A Short Note on Band Structure of Transition Metal Solids
	5.2 Charge Distribution and Bonding in the MO LCAO Method. The Case of Weak Covalency
		5.2.1 Atomic Charges and Bond Orders
			Example 5.1. Shortcomings of Mulliken’s Definition of Atomic Charges in Molecules
		5.2.2 Bonding, Nonbonding, and Antibonding Orbitals
		5.2.3 Case of Weak Covalency
		5.2.4 Angular Overlap Model
	5.3 Methods of Calculation of MO Energies and LCAO Coefficients
		5.3.1 SCF MO LCAO Approximation
		5.3.2 Electron Correlation Effects
		5.3.3 Basis Sets and Pseudopotentials
			EXAMPLE 5.2 Calculate the CuF2 Molecule Using Hartree–Fock and MP2 Methods
			Example 5.3. Calculate the Absorption and Emission spectra of [Cr(ddpd)2]3+ (ddpd = N,N -dimethyl- N,N -dipyridin-2-ylpyridine-2,6-diamine) using CASSCF and CASPT2 Methods
	5.4 Density Functional Theory
		5.4.1 Hohenberg–Kohn (HK) Method
		5.4.2 Exchange-Correlation Functional
		5.4.3 Time-Dependent DFT (TD-DFT)
		5.4.4 Density-Functional Tight Binding (DFTB)
			Example 5.4. Calculation of ZnCl2 by the DFT Method
			Example 5.5. DFT Calculation of the Energy of Absorption of the O2 on the Surface of CoN4-ZnN4/C Material
	5.5 Electronic Structure Calculations for Large Polyatomic Systems
		5.5.1 Fragmentary Calculations
		5.5.2 Molecular Mechanics
			Example 5.6. Application of Molecular Modeling to Transition Metal Complexes with Macrocycles
		5.5.3 Combined Quantum/Classical (QM/MM) Methods
			EXAMPLE 5.7 Oxidative Addition of H2 to Pt(P(t-Bu)3)2 Treated by ONIOM Version ofQM/MM Methods
			Example 5.8. Iron Picket-Fence Porphyrin Treated by the QM/MM Method with Charge Transfer (QM/MM/CT)
		5.5.4 Machine Learning Force Fields (MLFF) Method
	5.6 Comparison of Methods and Computer Programs
	Summary Notes
	Exercises and Problems
	References
6. Electronic Structure and Chemical Bonding
	6.1 Classification of Chemical Bonds by Electronic Structure and Role of d and f Electrons in Coordination Bonding
		6.1.1 Criticism of the Genealogical Classification
		6.1.2 Classification by Electronic Structure and Properties
		6.1.3 Features of Coordination Bonds
		6.1.4 Coordination Bonding by Pre- and Post-transition Elements
	6.2 Qualitative Aspects and Electronic Configurations
		6.2.1 Most Probable MO Schemes
		6.2.2 Electronic Configurations in Low- and High-Spin Complexes
		6.2.3 Covalence Electrons and Ionization Potentials
	6.3 Ligand Bonding
		6.3.1 General Considerations: Multiorbital Bonds
		6.3.2 Mono-orbital Bonds: Coordination of NH3 and H2O
			Example 6.1. Ab Initio Numerical SCF CI Calculations of the Electronic Structure of Mono-orbital Bonds: Ni(H2O)n and Ni(PH3)n, n =1, 2
		6.3.3 Diorbital Bonds: Coordination of the N2 Molecule
			Example 6.2. Electronic Structure and Bonding in FeN2
		6.3.4 Coordination of Carbon Monoxide
			Example 6.3. Bonding and Charge Transfer in the Pt—CO Complex
			Example 6.4. Bonding in M—CO with M = Cr, Fe, Co, Ni
			Example 6.5. Bonding in Sc—CO, Ni—CO, and Ni(CO)2
		6.3.5 σ + π Bonding
			Example 6.6. Electronic Structure of Transition Metal Hexacarbonils M(CO)6
		6.3.6 CO Bonding on Surfaces
		6.3.7 Bonding of NO
			Example 6.7. Coordination of NO on the Ni(111) Surface
		6.3.8 Coordination of C2H4
			Example 6.8. Ethylene Bonding to Transition Metal Centers
			Example 6.9. Ethylene Bonding in PtCl3(C2H4)- and PdCl3(C2H4)-
		6.3.9 Metal–Metal Bonds and Bridging Ligands
			Example 6.10. Multiple Metal–Metal Bonds in [Re2Cl8]2- and [Mo2Cl8]4-
	6.4 Energies, Geometries, and Charge Distributions
		6.4.1 Ionization Energies
			Example 6.11. Ab Initio Calculations of Ni(C3H5)2
		6.4.2 Total and Bonding Energies, Geometries, and Other Properties
	6.5 Relativistic Effects
		6.5.1 Relativistic Approaches
		6.5.2 Orbital Contraction and Valence Activity
			Example 6.12. Relativistic Effects in Catalytic Activity of Pt and Pd Complexes
		6.5.3 Bond Lengths, Bond Energies, and Vibrational Frequencies
			Example 6.13. Relativistic Effects in Metal Hydrides
		6.5.4 Correlation Between Spin-Orbital Splitting and Bonding
			Example 6.14. Relativistic Semiempirical Calculation of PtCl6 2-
		6.5.5 Other Relativistic Effects
	Summary Notes
	Exercises and Problems
	References
7. Vibronic Coupling in Formation, Deformation, and Transformation of Polyatomic Systems. The Jahn–Teller Effects
	7.1 Molecular Vibrations
		7.1.1 Adiabatic Approximation
		7.1.2 Normal Coordinates and Harmonic Vibrations
		7.1.3 Special Features of Vibrations of Coordination Compounds
	7.2 Vibronic Coupling
		7.2.1 Vibronic Constants
		7.2.2 Orbital Vibronic Constants
			Example 7.1. Vibronic MO Description of Electronic Structure of N2 and CO
	7.3 The Jahn–Teller Effects
		7.3.1 The Jahn–Teller Theorem
		7.3.2 The Pseudo-Jahn–Teller Effect
		7.3.3 Hidden-Jahn–Teller and Hidden Pseudo-Jahn–Teller Effects. Four Modifications of Jahn–Teller Effects
			Example 7.2. Hidden-JTE Origin of Instability of the High-Symmetry Configuration of the Ozone Molecule
		7.3.4 Configurations with h-PJTE and Spin Crossover
			Example 7.3. Hidden-PJTE Origin of Instability of the High-Symmetry Configuration of the CuF3 Molecule
		7.3.5 The Renner–Teller Effect
		7.3.6 The Jahn–Teller Effect in a Twofold-Degenerate Electronic State
		7.3.7 Threefold-Degenerate Electronic States
	7.4 Pseudo-Jahn–Teller Effect and the Two-Level Paradigm
		7.4.1 Pseudo-Jahn–Teller (PJT) Instability
		7.4.2 Uniqueness of the Vibronic Mechanism of Structural Configuration Instability. The Two-Level Paradigm
			Example 7.4. Numerical Confirmation of the Pseudo-Jahn–Teller Origin of Instability of High-Symmetry Configurations of Simple Molecules
			Example 7.5. Numerical Calculations Confirming the Pseudo-Jahn–Teller Origin of Configuration Instability of Coordination Systems
		7.4.3 Further Insight into the Pseudo-JTE and Hidden JTE
			Example 7.7. Why Some ML2 Molecules (M = Ca, Sr, Ba; L = H, F, Cl, Br) are Bent While Others Are Linear?
			Example 7.8. Direct Applications of the Jahn–Teller Effects in Materials Science and Engineering
			Example 7.6. Comparison of Covalence Versus Polarization Contributions to PJT Instability
	Summary Notes
	Exercises and Problems
	References
8. Electronic Structure Investigated by Physical Methods
	8.1 Band Shapes of Electronic Spectra
		8.1.1 Qualitative Interpretation of Vibrational Broadening
			Example 8.1. Broad and Narrow Bands in Light Absorption and Emission by Transition Metal Complexes
		8.1.2 Theory of Absorption Band Shapes
		8.1.3 Band Shapes of Electronic Transitions Between Nondegenerate States; Zero-Phonon Lines
		8.1.4 Types of Electronic Transitions on Intensity
			Example 8.2. Selection Rules for Polarized Light Absorption by the PtCl4 2– Complex
	8.2 d–d, Charge Transfer, Infrared, and Raman Spectra
		8.2.1 Origin and Special Features of d–d Transitions
			Example 8.3. d–d Transitions in the Absorption Spectrum of Mn(H2O)6 2+
			Example 8.4. Temperature-Dependent Absorption Spectra of K2NaCrF6 and Emerald
		8.2.2 Spectrochemical and Nephelauxetic Series
		8.2.3 Charge Transfer Spectra
			Example 8.5. Some Ligand Metal or Metal Ligand Charge Transfer Spectra
		8.2.4 Infrared Absorption and Raman Scattering
			Example 8.6. Resonance Raman Spectrum of Red K2[Ni(dto)2] in Solid State
		8.2.5 Transitions Involving Orbitally Degenerate States
	8.3 X-ray and Ultraviolet Photoelectron Spectra; EXAFS
		8.3.1 General Ideas
			Example 8.7. Photoelectron Spectra of Specific Coordination Systems and Their Interpretation
		8.3.2 Electron Relaxation; Shakeup and CI Satellites
			Example 8.8. Configuration Interaction Satellite to the K+ 3s Emission Line in the UPS Spectrum of KF
		8.3.3 Chemical Shift
			Example 8.9. The 1s Line of Nitrogen in the XPS of Different Coordination Systems Reflecting the Variety of Its Bonding in Different Groups
		8.3.4 EXAFS and Related Methods
			Example 8.10. Applications of EXAFS Spectroscopy to a Variety of Problems
	8.4 Magnetic Properrties
		8.4.1 Magnetic Moment and Quenching of Orbital Contribution
		8.4.2 Paramagnetic Susceptibility
		8.4.3 Electron Spin Resonance (ESR)
		8.4.4 Magnetic Exchange Coupling
			Example 8.11. Magnetic Exchange Coupling in Binuclear Copper Acetate Hydrate
			Example 8.12. The Nature of Metal–Metal Bonding in Binuclear Copper Acetate Hydrate
		8.4.5 Spin Crossover
		8.4.6 Magnetic Circular Dichroism (MCD)
	8.5 Gamma-resonance Spectroscopy
		8.5.1 The Mossbauer Effect
		8.5.2 .-Resonance Spectra
		8.5.3 Isomer Shift and Quadrupole Splitting in GRS
		8.5.4 Hyperfine Splitting
			Example 8.13. Magnetic Hyperfine Structure in GRS of Coordination Compounds with a 57Fe Nucleus
			Example 8.14. Observation of Spin Crossover in the .-Resonance Spectrum of [Fe(phen)2 (NCS)2]
	8.6 Electron Charge and Spin Density distribution in Diffraction Method
		8.6.1 The Method of Deformation Density
			Example 8.15. Deformation Density in Sodium Nitroprusside (Direct Inspection)
			Example 8.16. Metal–Metal Bonding in Mn2(CO)10; Fragment Deformation Density
			Example 8.17. Density Modeling for Fe(II)– Phthalocyanine and Co(II)–Tetraphenylporphyrin
		8.6.2 Spin Densities from Neutron Scattering
			Example 8.18. Spin Distributions in Some Coordination Systems Obtained from Neutron Scattering
	Summary Notes
	Exercises and Problems
	References
9. Stereochemistry and Crystal Chemistry
	9.1 Definitions. Semiclassical Approaches
		9.1.1 The Notion of Molecular Shape
		9.1.2 Directed Valences, Localized Electron Pairs, and Valence Shell Electron Pair Repulsion (VSEPR)
		9.1.3 Nonbonding Orbitals and Nodal Properties
			Example 9.1. Influence of Nonbonding MOs on Coordination Geometry
		9.1.4 Complementary Spherical Electron Density Model
			Example 9.2. The Inert-Gas Rule in Stereochemistry of Some Coordination Compounds
	9.2 Vibronic Effects in Stereochemistry
		9.2.1 Nuclear Motion Effects: Relativity to the Means of Observation and Vibronic Amplification of Distortions
		9.2.2 Qualitative Stereochemical Effects of Jahn–Teller and Pseudo-Jahn–Teller Distortions
			Example 9.3. Stereochemistry of MXn Systems Controlled by Electronic Structure and Vibronic Coupling
			Example 9.4. Pseudo-JT Origin of Distortions in CuCl3- 5 Versus ZnCl3- 5
		9.2.3 Off-Center Position of the Central Atom
		9.2.4 Geometry of Ligand Coordination
		9.2.5 Stereochemically Active and Inert Lone Pairs
		9.2.6 Pseudorotations in Coordination Systems
	9.3 Mutual Influence of Ligands
		9.3.1 The Model: Trans and Cis Influences in Stereochemistry
		9.3.2 Electronic Factors
		9.3.3 Vibronic Theory of Ligand Mutual Influence
	9.4 Crystal Stereochemistry
		9.4.1 The Plasticity Effect
		9.4.2 Distortion Isomers
			Example 9.5. Origin of Distortion Isomers in Cu (NH3)2 X2, X = Cl, Br
		9.4.3 Temperature-Dependent Solid-State Conformers
		9.4.4 Cooperative Effects: Order-Disorder and “Displacive” Phase Transitions and Helicoidal Structures
	Summary Notes
	Exercises and Problems
	References
10. Charge Transfer, Redox Properties, and Electron-conformational Effects
	10.1 Electron Transfer and Charge Transfer by Coordination
		10.1.1 Intramolecular Charge Transfer and Intermolecular Electron Transfer
			Example 10.1. Donor-acceptor PtII Complexes with Intramolecular Electron Transfer for Light Harvesting
		10.1.2 Solvation-driven Charge Transfer
		10.1.3 Redox Capacitance
			Example 10.2. Charge Transfer by Coordination of Peroxide to Iron Porphyrin
		10.1.4 Hard and Soft Acids and Bases
	10.2 Electron Transfer in Mixed-Valence Compounds
		10.2.1 Mixed-Valence Compounds as Electronic Systems; a Two-Level Dimer
			Example 10.3. The Creutz–Taube (CT) Ion as a Mixed-Valence System
		10.2.2 Magnetic Properties
		10.2.3 Mixed-Valence Trimers: Coexistence of Localized and Delocalized States
			Example 10.4. Tricenter Ferredoxin
	10.3 Electron-Conformational Effects In Biological Systems
		10.3.1 Distortions Produced by Excess Electronic Charge; Special Features of Metalloenzymes
		10.3.2 Trigger Mechanism of Hemoglobin Oxygenation: Comparison with Peroxidase
	Summary Notes
	Exercises and Problems
	References
11. Reactivity and Catalytic Action
	11.1 Electronic Factors in Reactivity
		11.1.1 Chemical Reactivity and Activated Complexes
		11.1.2 Transition (Activation) States of Chemical Reactions Are Controlled by the Pseudo-Jahn–Teller Effect
		11.1.3 Frontier Orbitals and Perturbation Theory
		11.1.4 Orbital Symmetry Rules in Reaction Mechanisms
			Example 11.1. Orbital Symmetry Rules and Vibronic Coupling in Formation of Cyclobutane from Ethylene with Catalyst Participation
	11.2 Electronic Control of Chemical Activation Via Vibronic Coupling
		11.2.1 Chemical Activation by Electron Rearrangement
		11.2.2 Activation of Small Molecules by Coordination
			Example 11.2. Activation of Carbon Monoxide
			Example 11.3. Numerical Estimate of CO Activation by Coordination to a NiO Surface
			Example 11.4. Numerical Estimates of N2, NO, and H2 Activation by Coordination to Transition Metal Centers
			Example 11.5. Activation of Oxygen by Hemoproteins
			Example 11.6. Quantum-mechanical Tunneling Reactions in Jahn–Teller Distorted Cu(II)N6 Complexes
	11.3 Direct Computation of Energy Barriers of Chemical Reactions
		11.3.1 Substitution Reactions: The trans Effect
		11.3.2 Ligand Coupling and Cleavage Processes
		11.3.3 Insertion Reactions
		11.3.4 Photochemical Reactions of Organometallics
			Example 11.7. Photochemistry of Ru(bpy)3 2+
	Summary Notes
	Questions and Problems
	References
Appendix 1. Tables of Characters of Irreducible Representations of Most Usable Symmetry Point Groups and Direct Products of Some Representations
Appendix 2. General Expressions for the Matrix Element Vmm of Perturbation of the States of one d Electron in Crystal Fields of Arbitrary Symmetry
Appendix 3. Calculation of the Destabilization and Splitting of the States of One d Electron in Crystal Fields of Different Symmetries
Appendix 4. Matrix Elements of Crystal Field Perturbation of a Two-Electron Term F(nd)2, Vij, i, j = 1,2,…, 7 Expressed by One-Electron Matrix Elements Vmm Given in Appendix 2
Appendix 5. Matrix Elements of Crystal Field Perturbation of f-Electron States
Answers and Solutions
Subject Index