Rational Synthesis, Structures and Properties of the Ionic Liquid Binary Iodine-Bromine Octahalide Series [I Br ] (n=0, 2, 3, 4).

A series of octanuclear iodine-bromine interhalides [I Br ] (n=0, 2, 3, 4) were prepared systematically in two steps. Firstly, addition of a dihalogen (Br or IBr) to the triaminocyclopropenium bromide salt [C (NEt ) ]Br forms the corresponding trihalide salt with Br or IBr anions, respectively. Secondly, addition to Br of half an equivalent of Br gives the octabromine polyhalide [Br ] , whereas addition to IBr of half an equivalent of Br , IBr or I gives the corresponding interhalides: [I Br ] , [I Br ] , and [I Br ] , respectively. The four octahalides were characterized by X-ray crystallography, computational studies, Raman and Far-IR spectroscopies, as well as by TGA and melting point. All of the salts were found to be ionic liquids.