Boron halogen compounds

Gmelin Handbook Volumes on Boron and its Compounds (a) Main Volume (1926) (b) Supplement vol. 1 (1954) (c) Compounds 8 (NSSV 33), The tetrahydroborate ion and its derivatives (1976) (d) Compounds 9 (NSSV 34), Boron-halogen compounds , Part 1 (1976) (e) Compounds 10 (NSSV 37), Boron compounds with coordination number 4 (1976) (f) Compounds 15 (NSSV 46), Amine-boranes (1977) (g) Compounds 19 (NSSV 53), Boron-halogen compounds , Part 2 (1978) (h) Supplement Volumes (1980-82), Springer-Verlag, Berlin. 

Borverbindungen 9 Boron-Halogen Compounds, Part 1. Literature coverage from 1950 to the end of 1974. 

Flame resistance A1203, antimony oxides, boron compounds, halogen compounds, phosphate esters, metal hydrates, magnesium compounds, tin compounds, molybdenum compounds, silicones Al, B, Br, Cl, Mo, P, Sb, Si, Sn, Zn... 

Lewis acids such as boron trihalides will also form stronger bonds with fluoride than with the other halogens, and can be used to abstract fluoride selectively from halogenated compounds. Some examples of Friedel-Crafts alkylations with fluoro-haloalkanes in which only fluoride is displaced are sketched in Scheme 4.14. As shown by the last example, however, hydride migrations can readily occur under such strongly acidic reaction conditions. 

Pohland, E. Concerning Non-metal Halogen Compounds. II. Information on Boron Tribromide. Z. anorg. Chem. 201. 282 (1931). 

In principle, oxidation could occur simultaneously during a HDH (reduction) reaction. For example any de-halogenated compounds could be oxidised to C02 in the anode compartment. Thus in the case of pentachlorophenol the phenol produced by the HDH could be oxidised at a suitable anode (e.g. boron-doped diamond) to C02 ... 

The fact that BF3 forms a wider range of complexes than the other tri-halides is probably due to a greater difficulty of heterolysis with the B—F bond than with the B—Cl and B—Br bonds. Thus molecules of the alcohols, aldehydes and ketones, which form addition compounds with BF3, break the boron-halogen bonds in the other halides ... 

Preparation. Diborane is generally made by treatment of sodium borohydride with boron trifluoride etherate. During a study of the reduction of organic halogen compounds with sodium borohydride, Bell et al. noted that the stoichiometry results in generation of diborane (as monomer) ... 

---