Metal dihydrogen and [sigma]-bond complexes / Gregory J. Kubas.

Format:

Book

Author/Creator:

Kubas, Gregory J., 1945-

Series:

Modern inorganic chemistry

Language:

English

Subjects (All):

Metal complexes.

Hydrogen.

Chemical bonds.

Physical Description:

xvi, 472 pages : illustrations ; 26 cm.

Other Title:

Metal dihydrogen and [sigma]-bond complexes : structure, theory, and reactivity

Place of Publication:

New York : Kluwer Academic/Plenum, [2001]

Summary:

According to R.H. Crabtree, Metal Dihydrogen and sigma-Bond Complexes is described as the definitive account of twentieth-century work in the area of sigma complexation'. It covers not only Kubas' discovery of dihydrogen coordination and the study of its structure and general properties but also discusses both the theoretical beliefs and experimental results of bonding and activation of dihydrogen on metal centers and the coordination and activation of C-H, B-H, X-H, and X-Y bonds, giving an overview of one of the hottest areas in chemistry'.

Contents:

1.1. Nonclassical Bonding in [sigma] Complexes 1

1.2. Small-Molecule Activation on Transition Metal Complexes 5

1.3. [sigma] Complexes As "Arrested Intermediates" along the Reaction Coordinate for [sigma]-Bond Cleavage 7

1.4. The Importance of Backdonation in [sigma]-Bond Coordination and Cleavage 10

1.5. Reactivity of [sigma]-Complexes: [sigma]-Bond Metathesis, Acidity, and Heterolytic Cleavage of X-H Bonds 12

2. Background and Discovery of Dihydrogen Coordination 17

2.1. Homogeneous Activation of Dihydrogen on Metal Complexes 17

2.2. Discovery of Dihydrogen Complexes 20

2.2.2. Discovery of Dihydrogen Coordination 24

2.2.3. The Development of Dihydrogen Coordination Chemistry 29

3. Synthesis and General Properties of Dihydrogen Complexes 33

3.1 Stable Dihydrogen Complexes 33

3.1.3. Complexes Synthesized by Addition of H[subscript 2] Gas to an Unsaturated Precursor 42

3.1.4. Complexes Prepared from H[subscript 2] Gas by Ligand Displacement or Reduction 45

3.1.5. Protonation of a Hydride Complex 46

3.1.6. Other Methods of Preparation 47

3.2. Dihydrogen Complexes Unstable at Room Temperature 48

3.2.1. Organometallic Complexes Observed at Low Temperature in Rare Gas or Other Media 48

3.2.2. Binding of H[subscript 2] to Bare Metal Atoms, Ions, and Surfaces 50

4. Bonding and Activation of Dihydrogen and [sigma] Ligands: Theory versus Experiment 59

4.2. Development of the Theoretical Aspects of Metal-Dihydrogen Bonding and Calculational Methodologies 61

4.3. Theoretical Studies of Oxidative Addition of Dihydrogen 63

4.4. Palladium (Dihydrogen)

The First Prediction of a Stable Dihydrogen Complex 67

4.5. Theoretical Studies of M(CO)[subscript 3](PR[subscript 3])[subscript 2](H[subscript 2]) and Bonding Model for Dihydrogen Coordination 69

4.6. Relative Strengths of Dihydrogen as a [pi] Acceptor and as a Donor Ligand Compared to Other Ligands 75

4.7. Dihydrogen versus Dihydride Coordination: Activation of Dihydrogen toward Oxidative Addition 79

4.7.1. The Crucial Influence of the Ligand trans to H[subscript 2] 81

4.7.2. Other Ligand/Metal/Charge Effects on H[subscript 2] Binding and Activation: Why FeH[subscript 2](CO)[subscript 4] Is a Dihydride 84

4.7.3. The Reaction Coordinate for OA: The Point at Which the H-H Bond Is Broken 88

4.7.4. Elongated Dihydrogen Complexes: Extraordinarily Delocalized Dynamic Systems 97

4.7.5. Further Aspects of Electronic and Steric Control of Dihydrogen versus Dihydride Bonding 104

4.8. Polyhydride-Dihydrogen Complexes 107

4.9. Cp and Tp Complexes, Including d[superscript 0] Systems 111

4.10. Polyhydride Complexes with CO versus Halide Ligands 114

4.11. Interaction of a Coordinated [sigma] Bond with a cis Ligand: The cis Effect in Hydride-Dihydrogen Complexes 115

4.12. Intramolecular Hydrogen Exchange, Polyhydrogen Complexes, and [sigma]-Bond Metathesis 121

4.13. Dihydrogen and Methane Binding to Naked Metal Ions 128

4.14. Interaction of Dihydrogen with Metal Surfaces, Metal Oxides and Hydrides, and Nontransition Metal Systems 131

5. Structural and NMR Studies of Dihydrogen Complexes 143

5.2. Diffraction Methods 145

5.3. Solid State NMR 148

5.4. Solution NMR: J[subscript HD] Coupling and Isotope Effects 150

5.5. NMR Relaxation Time T[subscript 1], Deuterium Quadrupole Coupling, and Effects of Dihydrogen Rotation 158

5.6. H-H Distance and Other Crystallographic and Structural Aspects of Dihydrogen Coordination 164

6. Intramolecular Dynamics of Dihydrogen-Hydride Ligand Systems: Hydrogen Rotation, Exchange, and Quantum-Mechanical Effects 171

6.2. Dihydrogen Rotation in M([eta superscript 2]-H[subscript 2]) 173

6.2.1. Determination of the Barrier to Rotation of H[subscript 2] 174

6.2.2. Inelastic Neutron Scattering 176

6.2.3. Origin of the Barrier to Rotation of [eta superscript 2]-H[subscript 2] 178

6.2.3.1. Metal-Hydrogen Binding 178

6.2.3.2. Effect of the Metal Center 179

6.2.3.3. Ligand Effects 182

6.2.3.4. Intramolecular Interactions and Crystal Packing Effects 184

6.2.4. Two-Dimensional Parameterized Model for H[subscript 2] Rotation 186

6.3. Intramolecular Hydrogen Rearrangement and Exchange 187

6.3.1. Extremely Facile Hydrogen Exchange in IrXH[subscript 2](H[subscript 2])(PR[subscript 3])[subscript 2] and Related Systems 190

6.3.2. Other Systems that Exchange Hydrogens in H[subscript 2] and Hydride Ligands 192

6.3.3. Quasi-Elastic Neutron Scattering Studies of H[subscript 2] Exchange with cis Hydrides 194

6.3.4. Quantum-Mechanical Exchange Coupling and Hindered Rotational Phenomena 198

7. Thermodynamics, Kinetics, and Isotope Effects of the Binding and Cleavage of [sigma] Ligands versus Classical Ligands 207

7.1. Themodynamics of Dihydrogen and [sigma]-Bond Coordination to Metal Centers 207

7.1.1. Binding Energies of H[subscript 2] and [sigma] Ligands to Stable Complexes 207

7.1.2. Binding Energies of H[subscript 2] and [sigma] Ligands to Thermally Unstable Metal Complexes 210

7.2. Binding Strength of Dihydrogen and [sigma] Ligands versus Classical Ligands; Importance of Entropy 213

7.3. Kinetics of Formation and Substitution of Dihydrogen, Alkane, and Related [sigma] Ligands 222

7.4. Reaction Profiles and Kinetics for Coordination and Oxidative Addition of Dihydrogen and Other [sigma] Ligands 226

7.5. Isotope Effects in [sigma]-Ligand Coordination and Oxidative Addition 233

7.5.1. Equilibrium Isotope Effects for H[subscript 2] versus D[subscript 2] Binding 234

7.5.2. Origin of the Inverse EIE for H[subscript 2] and Other [sigma]-Ligand Binding and EIE for OA 235

7.5.3. Kinetic Isotope Effects for H[subscript 2] and Alkane OA and Reductive Elimination 238

8. Vibrational Studies of Coordinated Dihydrogen 245

8.1. Vibrational Modes for [eta superscript 2]-H[subscript 2] 245

8.2. Normal Coordinate Analysis of W(H[subscript 2])(CO)[subscript 3](PCy[subscript 3])[subscript 2] 249

8.3. Bonding Character of Dihydrogen Complexes Suggested by Vibrational Analysis 253

8.4. Highly Mixed H-H and M-H[subscript 2] Modes in Elongated Dihydrogen Complexes: New Normal-Mode Definitions 255

9. Reactions and Acidity of Dihydrogen Complexes 259

9.2. Homolytic Splitting of Coordinated Dihydrogen 261

9.3. Isotopic Exchange and Other Intramolecular Hydrogen Exchange Reactions 265

9.4. Heterolytic Cleavage and Acidity of Coordinated Dihydrogen 270

9.4.2. Thermodynamic and Kinetic Acidity of H[subscript 2] Ligands 273

9.4.3. Intermolecular Heterolytic Cleavage of Coordinated H[subscript 2] 278

9.4.4. Intramolecular Heterolytic Cleavage 280

9.4.4.1. Proton Transfer to Ancillary Ligands and H[subscript 2] Bonding 280

9.4.4.2. Proton Transfer to Anions 283

9.5. Catalytic Hydrogenation and Related Reactions 284

9.5.1. Direct Transfer of Hydrogen from H[subscript 2] Ligands 284

9.5.2. H[subscript 2] Complexes as Precursors for Catalytic and Other Reactions 288

9.5.3. Ionic Hydrogenation and Zeolite-Catalyzed Hydrogenation 290

10. Activation of Hydrogen and Related Small Molecules by Metalloenzymes and Sulfur Ligand Systems 297

10.1. Hydrogenases: Biorganometallic Formation and Splitting of Dihydrogen 297

10.1.2. [NiFe] H-ases 300

10.1.3. A Metal-Free Hydrogenase 306

10.1.4. [Fe] Hydrogenases: Highly Organometallic Active Sites 307

10.2. Nitrogenases and Nitrogen Fixation 312

10.3. Hydrocarbon Activation by Oxygenase Enzymes 316

10.4. Models for Biological and Industrial Activation of Hydrogen on Sulfur Ligands and Sulfides 319

11. Coordination and Activation of Si-H, Ge-H, and Sn-H Bonds 327

11.2. Synthesis and Characterization of M([eta superscript 2]-Si-H) Complexes 330

11.3. Si-H Bonding to Metals Compared to M-H[subscript 2] Bonding 342

11.3.1. Comparisons of H-H versus Si-H [sigma]-Bond Activation and OA Processes 344

11.3.2. Theoretical Studies of Si-H versus H-H [sigma]-Bond Activation 349

11.4. Reactions and Dynamics of [sigma]-Silane Complexes 352

11.4.1. Heterolytic Cleavage of M([eta superscript 2]-Si-H) and Related

Reactions 353

11.4.2. Dynamics of Silane Ligands and Exchange with cis Hydrides 355

11.5. Germane and Stannane [sigma] Complexes 357

12. C-H Bond Coordination and Activation 365

12.2. Agostic C-H Coordination and Cyclometallation 367

12.2.1. Structures and Strengths of M ... H-C Interaction 367

12.2.2. Cyclometallation and Oxidative Addition of Agostic C-H Bonds 374

12.2.3. Agostic Interactions in Phosphine Complexes 378

12.3. Alkane Coordination 383

12.3.1. Experimental Evidence 383

12.3.2. Theoretical Studies of Alkane Activation and C-H versus C-F Bond Coordination 388

12.4. Evidence for [sigma] Complexes in the Oxidative Addition and Reductive Elimination of C-H Bonds 395

12.4.1. Isotopic Exchange in Intermediates in RE and OA of Alkanes and Other Transformations 395

12.4.2. Direct Spectroscopic Evidence for Alkane Complexes as Intermediates in OA of Alkanes 399

12.4.3. Shilov Chemistry and Related Electrophilic Systems for Homogeneous Alkane Oxidation 403

13. Coordination and Activation of B-H and Other X-H and X-Y Bonds 417

13.1. B-H Bonds 417

13.1.1. Metal Borohydride and Agostic-Like Systems 417

13.1.2. [sigma] Complexes of Neutral Boranes 421

13.2. X-H [sigma] Interactions Where X Is Also a Lone-Pair Donor (N, P, S) 429

13.3. Interactions of [sigma] Bonds X-Y Where X and Y Are Not Hydrogen 431

13.3.1. C-Halogen Bonds 431

13.3.2. C-C, C-Si, C-N, and C-B Bond Interactions with Metal Centers 432

13.3.3. Activation of C-P bonds in Phosphines 435

13.4. Summary and a Glance to the Future 436.

Notes:

Includes bibliographical references and index.

ISBN:

0306464659

OCLC:

44613203