Construction of Ternary Iodine-Bromine-Chlorine Octahalides.

A series of five ternary octanuclear iodine-bromine-chlorine interhalides, [I Br Cl ] (1), [I BrCl ] (2), [I Br Cl ] (3), [I Br Cl ] (4) and [I Br Cl ] (5), have been rationally constructed in two steps. Firstly, addition of a dihalogen (ICl or IBr) to the triaminocyclopropenium chloride salt [C (NEt ) ]Cl forms the corresponding trihalide salt with [ICl ] or [BrICl] anions, respectively. Secondly, addition of a half-equivalent of a second dihalogen, followed by crystallization at low temperature, gives the corresponding octahalide: addition of Br and IBr to [ICl ] gives 1 and 2, respectively, whereas addition of I , Br and IBr to [BrICl] gives 3, 4 and 5, respectively. The five octahalides were characterized by X-ray crystallography and far-IR spectroscopy.