Nuclear Magnetic Resonance Spectroscopy of Boron Compounds

The revolutionary impetus of the NMR methods in organic chemistry has parallels in the field of boron chemistry. lIB NMR spectroscopy provided a basis for the elucida­ tion of structures and reactions of the boron hydrides. However, although many studies have been carried out with the higher boranes, carboranes, metalloboranes, etc. , and although certain patterns have emerged, the correlation between the observed chemical shift and the assigned structural unit is still not fully understood. Therefore, predictions in this area are still rather limited, and semiquantitative interpretations are not yet pos­ sible. Several years ago Eaton and Lipscomb sUpImarized the status in this field in their book "NMR Studies of Boron Hydrides and Related Compounds" and a plethora of new data has accumulated since then. The book also contained material on simple bo­ rane derivatives, but they were not discussed in any detail. On the other hand many systematic studies, both synthetic and spectroscopic, have been conducted on these simple boron materials in the last decade. Thus a large amount of NMR information is available, not only on lIB but also on 1 H, 1 3 C, and 14 N. However, this information is widely scattered in the literature, and often the data are not discussed at all. It see­ med appropriate, therefore, to collect these data and to present them in one volume.

Contenu

1 Introduction and Scope.- 1.1. Application of 11 B NMR Spectroscopy.- 1.1.1. Investigation of Structures.- 1.1.2. Investigation of Reactions.- 1.1.3. Application in Analysis.- 1.2. Scope.- Literature to Chapter 1.- 2 Nuclear Magnetic Properties of Boron.- 2.1. The Isotopes 10 B,11 B.- 2.2. Information from Boron NMR Data.- 2.2.1. Chemical Shifts.- 2.2.2. Coupling Constants between Boron and Other Nuclei.- 2.2.3. Relaxation and Line Width.- 2.2.4. Paramagnetic Compounds.- 2.2.5. Exchange Processes.- 2.3. Chemical Shifts.- 2.3.1. Theory of Chemical Shifts.- 2.3.2. Empirical Correlations of 11 B Chemical Shifts.- 2.3.3. Semiempirical Calculations.- 2.4. Spin-Spin Coupling.- 2.4.1. Theory of Spin-Spin Coupling.- 2.4.2. Empirical and Semiempirical Correlation of Coupling Constants 1 J(11 BX).- Literature to Chapter 2.- 3 11B NMR of Two-Coordinate Boron.- 4 11B Chemical Shifts of Three-Coordinate Boron.- 4.1. Survey of Substituent Effects.- 4.1.1. ?- and ?-Bonding Effects.- 4.1.2. Anisotropy Effects.- 4.1.3. Effects of Ring Size and Steric Hindrance.- 4.2. Triorganylboranes.- 4.2.1. Trialkylboranes.- 4.2.2. Carbon-Substituted Trialkylboranes.- 4.2.3. Unsaturated Triorganylboranes-Site of Unsaturation Adjacent to Boron.- 4.3. Halogenoboranes.- 4.3.1. Trihalogenoboranes.- 4.3.2. Halogeno(organyl)boranes.- 4.3.3. Pseudohalogenoboranes and Pseudohalogeno(organyl)boranes.- 4.4. Boranes with Boron-Oxygen Bonds.- 4.4.1. Esters of Boric Acid and Organylboric Acids.- 4.4.2. Boroxines.- 4.4.3. Halogeno(organyloxo)boranes and Halogenoorganyl(organyloxo)-boranes.- 4.5. Boranes with Boron-Sulfur Bonds.- 4.5.1. Tris(organylthio)boranes and Organyl(organylthio)boranes.- 4.5.2. Borthiines.- 4.5.3. Organylthioboranes Containing B-C, B-O, B-Halogen Bonds.- 4.6. Boranes with Boron-Selenium Bonds.- 4.7. Boranes with Boron-Nitrogen Bonds.- 4.7.1. Monoaminoboranes.- 4.7.1.1. Aminoorganylboranes.- 4.7.1.2. Cyclic Monoamino(organyl)boranes.- 4.7.1.3. B-Functional Monoaminoboranes.- 4.7.1.4. N-Substituted Monoaminodiorganylboranes.- 4.7.1.5. B,N-Functional Monoaminoboranes.- 4.7.2. Bis(amino)boranes.- 4.7.2.1. Bis(amino)organylboranes.- 4.7.2.2. B-Functional Bis(amino)boranes.- 4.7.2.3. N-Functional Bis(amino)boranes.- 4.7.2.4. B,N-Functional Bis(amino)boranes.- 4.7.3. Tris(amino)boranes.- 4.7.4. Diborylamines and Triborylamines.- 4.7.4.1. Bis(diorganylboryl)amines and Tris(diorganylboryl)amines.- 4.7.4.2. B-Substituted Diborylamines.- 4.7.5. Ketimino and Aldimino Boranes.- 4.7.6. Hydrazino(organyl)boranes.- 4.7.7. Diazaboracycloalkanes.- 4.7.7.1. Diazaborolidines.- 4.7.7.2. Diazaborinanes and Higher Homologues.- 4.7.8. Borazines.- 4.7.9. Six-Membered Boron Nitrogen Heterocycles Derived from Borazines Containing Heteroatoms Other than Carbon.- 4.7.10. BN Isoconjugate Cyclic Polyenes.- 4.7.11. Boron Heterocycles Containing a Hydrazino Group.- 4.7.11.1. 1,2,4,3,5-Triazadiborolidines.- 4.7.11.2. Hexahydro-Tetrazadiborines.- 4.7.11.3. Boron Heterocycles Containing a Hydrazino Group and Ring Atoms Other than Boron.- 4.7.12. 1,2,3,4,5-Tetrazaborolines(2).- 4.7.13. Four-and Eight-Membered BN Heterocycles.- 4.8. Diboron and Polyboron Compounds.- 4.9. Boranes with Boron-Hydrogen Bonds.- 4.10. Boranes with Boron-Silicon, Boron-Germanium, Boron-Tin, and Boron-Lead Bonds.- 5 11B NMR of Transition Metal Boron Compounds.- 6 11B NMR of Diborane and Derivatives.- 6.1. Diborane.- 6.2. Organyldiboranes.- 6.3. µ-Substituted Diboranes.- 6.4. Heptahydrodiborates and µ-Substituted Derivatives.- 7 11B NMR of Tetracoordinate Boron.- 7.1. Metal Tetrahydroborates.- 7.1.1. Alkali Metal Tetrahydroborates.- 7.1.2. Alkaline Earth Metal Tetrahydroborates.- 7.1.3. Aluminium Tetrahydroborates.- 7.1.4. Transition Metal Tetrahydroborates.- 7.2. Substituted Metal Tetrahydroborates.- 7.3. Metal Borates MBX4 and [BX4-nYn].- 7.3.1. Metal Tetraorganylborates.- 7.3.2. Metal Halogenoborates.- 7.3.3. Metal Borates with Various Substituents.- 7.4. Donor-Acceptor Complexes.- 7.4.1. Survey of Donor-Acceptor Properties.- 7.4.2. Boron Adducts with Oxygen Donors.- 7.4.3. Boron Adducts with Sulfur and Selenium Donors.- 7.4.4. Boron Adducts with Nitrogen Donors.- 7.4.4.1. Boron Adducts with Tetracoordinate Nitrogen.- 7.4.4.2. Boron Adducts with Three-Coordinate Nitrogen.- 7.4.4.3. Boron Adducts with Two-Coordinate Nitrogen.- 7.4.5. "Boronium" Salts [Bis(amine)dihydroboron]-Cations.- 7.4.6. "Chelate Complexes".- 7.4.7. Borane Adducts with Phosphorous Donors.- 7.4.7.1. BH3 Adducts of Phosphines.- 7.4.7.2. Organylborane Phosphines.- 7.4.7.3. Trihalogenoborane Phosphines.- 7.4.7.4. Halogeno(hydrido)borane and Halogeno(organyl)borane Phosphines.- 7.4.7.5. Phosphine Adducts of Mixed Substituted Boranes.- 7.4.7.6. Cyclic Phosphinoboranes.- 7.4.8. Borane Adducts of Arsines and Stibines.- 8 Spin-Spin Coupling Constants nJ(11 BX).- 8.1. Spin-Spin Coupling Between Boron and Hydrogen.- 8.2. Boron-Boron Coupling Constants.- 8.3. Coupling Constants of Boron and Group IV Elements.- 8.3.1. Spin-Spin Coupling Between Boron and Carbon.- 8.3.2. Spin-Spin Coupling Between Boron and Silicon, Tin, and Lead.- 8.4. Spin-Spin Coupling Between Boron and Group V Elements.- 8.4.1. Spin-Spin Coupling Between Boron and Nitrogen.- 8.4.2. Spin-Spin Coupling Between Boron and Phosphorus.- 8.5. Coupling Between Boron and Group VI Elements.- 8.6. Coupling Between Boron and Fluorine.- 8.7. Spin-Spin Coupling Between Boron and Transition Metals.- 9 Tables of 11B-NMR Data.- 9.1. Remarks on the Organization of the Tables.- 9.2. List of Tables, Including Structural Symbols.- 9.3. Tables.- 9.4. CA Formula Index.- References.- Author Index.