Carboranes

Preface


1. Introduction


2. Structures and Bonding


2-1. Structures of the Carboranes

The Polyhedral Carboranes

The Open-Cage Carboranes

Isomerism and Rearrangement


2-2. Nomenclature and Numbering Systems


2-3. Chemical Bonding in the Boranes and Carboranes

The Three-Center Bond

Molecular Orbitals in Boranes and Carboranes

Simplified Molecular Orbital Descriptions

Summary


3. The Small Nido-Carboranes: CB5H9, C2B4H8, C3B3H7, C4B2H6, and C2B3H7


3-1. Structures


3-2. Synthesis

Borane-Alkyne Reactions

Other Routes to Möfo-Carboranes


3-3. Reactions and Properties


2-CB5H9


2,3-C2B4H8


2,3,4-C3B3H7


2,3,4,5-C4B2H6


1,2-C2B3H7


4. The Small Closo-Carboranes: C2B3H5, C2B4H6, C2B5H7, and CB5H7


4-1. Synthesis

Borane-Alkyne Reactions

Conversions of Nido-Carboranes to Closo-Carboranes

Reactions of Alkylboranes with Alkynes

Hydroboration of Alkynylboranes

Dehalogenation of Alkylhaloboranes with Alkali Metals

Pyrolysis and Electric Discharge of Alkylboranes

Reaction of Boranes with Carbon Vapor


4-2. Structures and Properties

C2B3H5

C2B4H6

C2B5H7

CB5H7


5. The Intermediate Closo-Carboranes: C2B6H8, C2B7H9, C2B8H10, and C2B9H11


5-1. Synthesis

Reactions of Boranes with Alkynes

Degradation of Icosahedral Carboranes


5-2. Structures and Properties

C2B6H8

C2B7H9

C2B8H10

C2B9H11

The 1,2-C2B10H12 (o-Carborane) System


6-1. Synthesis, Structure, and Properties

Synthesis

Structure

Thermal Stability and Rearrangement

Chemical Properties


6-2. Alkali Metal and Magnesium Derivatives

Alkali Metal Derivatives

Magnesium Derivatives

Zinc Derivatives

Formation of o-Carborane Dianions in Liquid Ammonia


6-3. Alkyl, Haloalkyl, and Aryl Derivatives

Synthesis

Substitution at Boron

Properties of Alkyl and Haloalkyl Derivatives

Properties of Aryl Derivatives


6-4. Alkenyl and Alkynyl Derivatives

Synthesis of C-Alkenyl Derivatives

Synthesis of B-Alkenyl Derivatives

Synthesis of Alkynyl Derivatives

Reactions of Alkenyl Derivatives

Reactions of Alkynyl Derivatives


6-5. Carboxylic Acids and Esters

Synthesis of C-Substituted Acids and Esters

Synthesis of B-Substituted Acids

Reactions of Acids and Esters


6-6. Alcohols and Ethers

Synthesis of Alcohols

Synthesis of Ethers

Reactions of Alcohols and Ethers


6-7. Aldehydes and Ketones

Synthesis of Aldehydes

Synthesis of Ketones

Reactions of Aldehydes and Ketones


6-8. Nitrogen Derivatives

Nitrates and Related Compounds

Amines, Azides, and Diazonium Salts

Amides

Cyano Derivatives

Other Nitrogen-Containing Derivatives


6-9. Phosphorus, Arsenic, and Antimony Derivatives


6-10. Silicon Derivatives

o-Carboranyl Silanes

o-Carboranyl Alkoxysilanes


6-11. Germanium and Tin Derivatives


6-12. Sulfur Derivatives


6-13. Halogen Derivatives

Electrophilic Halogenation

Photochemical Halogenation

Fluorination

Synthesis of Halo-o-Carboranes from Decaborane(14) Halogen Derivatives

Synthesis of 3-Halo-o-Carboranes

Synthesis of C-Halo-o-Carboranes

Reactions of Halogen Derivatives


6-14. Sigma-Bonded Transition Metal Derivatives


6-15. Mercury Derivatives


7. The 1,7-C2B10H12 and 1,12-C2B10H12 (m- and p-Carborane) Systems


7-1. Comparison of o- and m-Carborane


7-2. Synthesis and Structure of m-Carborane


7-3. Mechanisms of Icosahedral Carborane Rearrangements

ortho-meta and meta-para Isomerizations

The "Reverse Isomerization" of m-Carborane: Conversion of m- to o-Carborane


7-4. Metallation of m-Carborane


7-5. Alkyl, Aryl, and Alkenyl m-Carborane Derivatives

Synthesis

Reactions


7-6. m-Carboranyl Carboxylic Acids and Esters

Synthesis

Reactions


7-7. m-Carboranyl Alcohols and Ethers

Synthesis

Reactions


7-8. m-Carboranyl Aldehydes and Ketones

Reactions


7-9. m-Carboranyl Nitrogen and Phosphorus Derivatives

Nitrates, Amines, and Diazonium Salts

Amides

Phosphorus Derivatives


7-10. m-Carboranyl Silicon Derivatives


7-11. m-Carboranyl Germanium, Tin, and Lead Derivatives


7-12. m-Carboranyl Sulfur Derivatives


7-13. m-Carboranyl Halogen Derivatives

Synthesis from Halo-o-Carboranes

Electrophilic Halogenation

Fluorination

Photochemical Halogenation

C-Halo-m-Carboranes

Reactions and Properties of Halo-m-Carboranes


7-14. m-Carboranyl Mercury Derivatives


7-15. p-Carborane

Synthesis and Structure

Organic and Organometallic Derivatives

Halogen Derivatives


8. Carborane Polymers


8-1. Introduction


8-2. General Considerations


8-3. Class I Polymers

Polyesters

Polyformals

Siloxanes

Polymers with Single Atom Links

Other Class I Polymers


8-4. Class II Polymers


9. Degradation of the Icosahedral Cage. Heteroatom Carboranes and Transition Metal π-Complexes


9-1. Degradation of o- and m-Carborane

C2B9H12- Ions

C2B9H13

C2B9H112- (Dicarbollide) Ions


9-2. Dicarbollide-Boron Insertion Reactions


9-3. The Monocarbon Carborane Anions: CB10H13-, CB10H11-, CB9H10-, CB11nH12-

CB10H13-

CB10H11-

CB9H10- and CB11H12-


9-4. Carboranes Containing Main-Group Cage Heteroatoms

Group II Heteroatoms

Group III Heteroatoms

Group IV Heteroatoms

Group V Heteroatoms


9-5. Carborane-Transition Metal π-Complexes

General Considerations

Dicarbollyl Complexes of Cr, Mo, and W

Dicarbollyl Complexes of Mn and Re

Dicarbollyl Complexes of Fe

Dicarbollyl Complexes of Co

Dicarbollyl Complexes of Ni and Pd

Dicarbollyl Complexes of Cu and Au

Monocarbollyl-Transition Metal π-Complexes

Carbaphosphollyl-Transition Metal π-Complexes

Nonicosahedral-Transition Metal π-Complexes

Supplementary Sources of Information

References

Author Index

Subject Index