[NMe₄][I₄Br₅]: A new Iodobromide from an Ionic Liquid with Halogen–Halogen Interactions

Abstract

Tetramethylammonium tetraiodopentabromide [NMe₄ ][I₄ Br₅ ] was the first iodobromide to be synthesized and crystallized in an ionic liquid as well as in dichloromethane. The new iodobromides show different structure motives yet are unknown from other nonahalides and can be better described as [(I₂ Br₃ )^- ⋅2 IBr]. The additional IBr units are connected by halogen-halogen interactions on the central V-shaped [I₂ Br₃ ]^- . The characterization was performed by Raman spectroscopy and single crystal X-ray structure determination. Conductivity measurements, thermogravimetric analysis and quantum-chemical calculations completed the structural discussion.