Hj. Frohn et al., CONTRIBUTIONS TO THE CHEMISTRY OF BROMINETRIFLUORIDE .2. BIS(PENTAFLUOROPHENYL)BROMONIUM CATIONS WITH WEAK NUCLEOPHILIC FLUOROELEMENTATE ANIONS, European journal of solid state and inorganic chemistry, 33(9), 1996, pp. 841-853
BrF3 reacts with M(II)(C6F5)(2) (M = Zn, Cd, Hg) in organic solvents i
ndependent of the stoichiometry under formation of C6F5BrF2. Bromonium
compounds [(C6F5)(2)Br](+) [EF(n+1)](-) (E = Sb, As, B) are formed in
equimolar reactions if additionally Lewis-acids EF(n) are present. [(
C6F5)(2)Br](+) [BF4](-) results in quantitative yield independent of t
he stoichiometry of substrates if BrF3 reacts with the Lewis-acidic ar
yl transfer reagent (C6F5)(2)BF. The molecular structure of the bromon
ium compounds [(C6F5)(2)Br](+) [BF4](-) and [(C6F5)(2)Br](+) [AsF6](-)
can be interpreted in terms of two asymmetric hypervalent bonds at br
omine(III). Ln solution the electrophilicity of Br(III) in [(C6F5)(2)B
r](+) [EF(n+1)](-) is responsible for the strong dependence of the F-1
9 NMR shift values from the nucleophilicity of the solvent.