[(Ph)3PBr][Br7], [(Bz)(Ph)3P]2[Br8], [(n-Bu)3MeN]2[Br20], [C4MPyr]2[Br20], and [(Ph)3PCl]2[Cl2I14]: Extending the Horizon of Polyhalides via Synthesis in Ionic Liquids

The five polyhalides [(Ph)3PBr][Br7], [(Bz)(Ph)3P]2[Br8], [(n-Bu)3MeN]2[Br20], [C4MPyr]2[Br20] ([C4MPyr] = N-butyl-N-methylpyrrolidinium), and [(Ph)3PCl]2[Cl2I14] were prepared by the reaction of dibromine and iodine monochloride in ionic liquids. The compounds [(Ph)3PBr][Br7] and [(Bz)(Ph)3P]2[Br8] contain discrete pyramidal [Br7]− and Z-shaped [Br8]2– polybromide anions. [(n-Bu)3MeN]2[Br20] and [C4MPyr]2[Br20] exhibit new infinite two- and three-dimensional polybromide networks and contain the highest percentage of dibromine ever observed in a compound. [(Ph)3PCl]2[Cl2I14] 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 Br2 and ICl and that, on the other hand, reduces the high volatility of the molecular halogens.