A large variety of polyhalides exists, where the known polyhalides increase in number starting from fluorine down to iodine. Whereas [F3]− and [F5]− have only been found in rare gas matrices at cryogenic conditions, several new polychlorides and polybromides have been prepared in bulk quantities over the last five years. The synthesis of polyhalides can be performed in numerous ways, one approach is the synthesis of the neat halogens. Nevertheless, the highest known polyhalides are all prepared in acetonitrile or ionic liquids. Consequently, the highest polychloride [Cl8]2− was successfully prepared in the ionic liquid [BMP][OTf] (1-Butyl-1-methyl-pyrrolidinium triflate). Polyhalides offer a wide range of applications. Opposed to performing chlorinations with hazardous gaseous elemental chlorine, one can use the easy to handle tetraalkylammonium trichloride. So, polyhalides present themselves as a useful alternative in the field of halogenation reagents. Polybromide monoanions in ionic liquids have been widely investigated. The unusually high conductivity of compounds such as [HMIM][Br9] (1-hexyl-3-methylimidazolium nonabromide) has attracted attention for application in electrochemistry, specifically flow batteries. Recent usage of [Br3]−/Br− as redox mediator in dye sensitized solar cells measured a higher open circuit photopotential compared to previously used [I3]−/I− systems.

Synthesis and application of novel polyhalides

253rd National Meeting (2017)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.