The chemistry of polyiodides is, compared to the other halogens, fluorine, chlorine and bromine, vast and has been extensively explored. Mono-, di-, tri- and tetra- polyiodide anions with different iodine contents, e.g. [I29]3– or [I26]4– are known.
In the last few years our research group has expanded the multifaceted polyhalide chemistry to the elements bromine, chlorine, and fluorine. The polybromide monoanions [Br9]– and [Br11]– were synthesized and structurally characterized in our group. The V-shaped pentachloride [Cl5]– as well as the nonachloride [Cl9]– were synthesized for the first time and characterized by Raman spectroscopy. In this context we are also investigating halogen-halogen bonding interactions to get a deeper insight into the structure of the polyhalide anion itself and the structure forming effects in the solid state.
Polyhalide compounds show interesting properties for example high electrical conductivities and are therefore not only of academic interest. Based on these results we are developing new energy storage materials.
Polyhalogenanionen - Überraschende Vielfalt
Heike Haller, Sebastian Riedel Nachrichten aus der Chemie, 2012, 9, 865–868
Recent Discoveries of Polyhalogen Anions – from Bromine to Fluorine
Heike Haller, Sebastian Riedel Z. Anorg. Allg. Chem. 2014, 640, 1281–1291
Own research on polyhalogen anions
The first structural proof for a higher polybromide monoanion. Investigation of [N(C3H7)4][Br9]
Heike Haller, Matthias Ellwanger, Alexander Higelin, Sebastian Riedel Angew. Chem. Int. Ed. 2011, 50, 11528
Beyond known Polyhalogens: Structural Proof of Undecabromide [Br11]-
Heike Haller, Jan Schröder, Sebastian Riedel Angew. Chem. Int. Ed. 2013, 52, 4937–4940
Polychloride Monoanions from [Cl3]- to [Cl9]-: A Raman-Spectroscopic and Quantum-Chemical Investigation
Robin Brückner, Heike Haller, Mathias Ellwanger, Sebastian Riedel Chem. Eur. J. 2012, 18, 5741-5747