[(Ph)_3PBr][Br_7], [(Bz)(Ph)_3P] _2[Br_8], [(n -Bu)_3MeN]_2[Br _(20)], [C_4MPyr]_2[Br_(20)], and [(Ph) _3PCl]_2[Cl_2I_(14)]: Extending the horizon of polyhalides via synthesis in ionic liquids

摘要

The five polyhalides [(Ph)_3PBr][Br_7], [(Bz)(Ph) _3P]_2[Br_8], [(n-Bu)_3MeN] _2[Br_(20)], [C_4MPyr]_2[Br_(20)] ([C_4MPyr] = N-butyl-N-methylpyrrolidinium), and [(Ph) _3PCl]_2[Cl_2I_(14)] were prepared by the reaction of dibromine and iodine monochloride in ionic liquids. The compounds [(Ph)_3PBr][Br_7] and [(Bz)(Ph)_3P] _2[Br_8] contain discrete pyramidal [Br_7] ~- and Z-shaped [Br_8]~(2-) polybromide anions. [(n-Bu)_3MeN]_2[Br_(20)] and [C_4MPyr] _2[Br_(20)] exhibit new infinite two- and three-dimensional polybromide networks and contain the highest percentage of dibromine ever observed in a compound. [(Ph)_3PCl]_2[Cl_2I _(14)] also consists of a three-dimensional network and is the first example of an infinite polyiodine chloride. All compounds were obtained from ionic liquids as the solvent that, on the one hand, guarantees for a high stability against strongly oxidizing Br_2 and ICl and that, on the other hand, reduces the high volatility of the molecular halogens.