Boron compounds, hydrides

Dimethylsulfoxide Acyl and aryl halides, boron compounds, bromomethane, nitrogen dioxide, magnesium perchlorate, periodic acid, silver difluoride, sodium hydride, sulfur trioxide... 

Boron trifluoride is used for the preparation of boranes (see Boron compounds). Diborane is obtained from reaction with alkafl metal hydrides organoboranes are obtained with a suitable Grignard reagent. 

Boron creates an electron deficiency in the siHcon lattice resulting in a -type semiconductor forp—n junctions. Boron compounds are more commonly used as the dopant, however (see Boron hydrides). 

To date, the most extensively studied polyboron hydride compounds in BNCT research have been the icosahedral mercaptoborane derivatives Na2[B22H22SH] and Na [(B22H22S)2], which have been used in human trials with some, albeit limited, success. New generations of tumor-localizing boronated compounds are being developed. The dose-selectivity problem of BNCT has been approached using boron hydride compounds in combination with a variety of deUvery vehicles including boronated polyclonal and monoclonal antibodies, porphyrins, amino acids, nucleotides, carbohydrates, and hposomes. Boron neutron capture therapy has been the subject of recent reviews (254). 

Boron Hydrides" under "Boron Compounds" in ECT 1st ed., Vol. 2, pp. 593—600, by S. H. Bauer, Cornell University "Boron Hydrides and Related Compounds" under "Boron Compounds," Suppl. 1, pp. 103—130, by S. H. Bauer, Cornell University "Diborane and Higher Boron Hydrides" under "Boron Compounds," Suppl. 2, pp. 109—113, by W. J. Shepherd and E. B. Ayres, Gallery Chemical Company "Boron Hydrides" under "Boron Compounds" in ECT 2nd ed., Vol. 3, pp. 684—706, by G. W. Campbell, Jr., U.S. Borax Research Corporation "Boron Hydrides and their MetaHo Derivatives" under "Boron Compounds," in ECT 3rd ed., Vol. 4, pp. 135—183, by R. W. Rudolph, The University of Michigan. 

Boron Compounds (Boron Hydrides)" in ECT 1st ed., Vol. 2, pp. 593—600, "Boron Compounds (Boron Hydride and Related Compounds)" Suppl. 1, pp. 103—130, by S. H. Bauer, Cornell University "Boron Compounds (Diborane and Higher Boron Hydrides)" Suppl. 2, pp. 109—113, byj. W. Shepherd and... 

Research Corp. "Boron Compounds (Boron Hydrides, Commercial Aspects)" in ECT3rd ed., Vol. 4, pp. 183—187, by G. B. Dunks, Union Carbide Corp. 

Another type of anion, confined for practical purposes to boron compounds, has no unshared electrons at the anionic site, and must be thought of as being formed by addition of hydride to a boron atom (or other atom with an incomplete valence shell). Such structures were not anticipated at the time general heterocyclic nomenclature was developed, and they are only recently being fitted into systematic nomenclature (lUPAC Provisional Recommendation 83.2). Proposals for a suffix to indicate such structures are under consideration (1982). 

Foremost among the elements that pack in icosahedral (and other Ar-chimedeans) structures is boron, its various hydrides (boranes), and related boron compounds (25 pp. 157-185). This topic, which is covered by numerous reviews and books, will not be further discussed in this chapter. Many other cage structures have been discussed in the literature, some of them are briefly discussed in (26). 

R. M. Adams, The boranes or boron hydrides in Boron, Metallo-Boron Compounds and Boranes, R. M. Adams, (Ed.), Interscience, New York 1964, p. 574. 

Wade electron counting rules borane-like cluster nomenclature. On initially studying compounds such as boranes (boron hydrides) and carboranes (or carbaboranes boron—carbon hydrides), Wade (1976) proposed a number of rules which have then been extended to several compounds and which relate the number of skeletal electrons with the structure of deltahedral clusters. A polyhedron which has only A-shaped, that is triangular, faces is also called a deltahedron. 

The most important application of boron is to make fibers or whiskers of single crystal or ceramic crystal. The addition of boron to metals, alloys, or other solids, imparts resistance to plastic flow, and thereby produces unusual strength in the material. Amorphous boron is used in rockets as an igniter, and in pyrotechnic flares to give green color. Many boron compounds, such as borax, boron hydrides, and boron hahdes, have important commercial applications (see individual compounds). 

Schubert DM (1993) Boron Compounds - Boron Hydrides, Heteroboranes and Their Metalla Derivatives. In Kirk-Othmer Encyclopedia of Chemical Technology, 4th Edn, John Wiley 8c Sons, New York and 5th Edn (2002) pubhshed on-line... 

Boron compounds contain two isotopes B10 and B11 of natural abundances 19% and 81%, respectively. Although both these isotopes possess magnetic moments, the Bn nucleus is better suited to the high resolution experiment because of its (1) greater natural abundance, (2) smaller quadrupole moment, and (3) larger nuclear moment. Because of the broad range of structures possible in boron compounds, particularly the hydrides, there has been considerable NMR work done in this field to confirm previously proposed structures and in a few cases to first establish geometry of a compound. The B11 spectra of tetraborane and a tetraborane derivative arc considered below. 

---