Halogenated materials from novel reactive halogenating ionic liquids

• Applicant: Professor Dr. Sebastian Hasenstab-Riedel
• Subject Area: Inorganic Molecular Chemistry - Synthesis and Characterisation
• Term: from 2017 to 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 376533928

This project aims for the synthesis and characterization of novel reactive halogenating ionic liquids and their application in the synthesis of new halogenated materials. The halogenating reagents consist of polyhalogen anions with the general formula [F(XF)n]- (with X = Cl, Br, I and n = 1-4). With suitable cations these interhalide salts represent ionic liquids themselves or they are used with ionic liquids as liquefier. Due to the high solubility of gases and the weak interactions with the solute, ionic liquids represent ideal media for the synthesis and application of such polyhalogen monoanions. Furthermore they can be designed to be highly resistant towards strong oxidizers like Cl2, ClF and even elemental fluorine. The polyhalogen monoanions will be prepared by the reaction of naked F- with halogenmonofluorides XF in suitable ionic liquids. Alternatively the reaction of polyhalide salts ([Cat]+[X(X2)n]-, X = Cl, Br, I and n = 1-4) with F2/N2 mixtures will be investigated. Such interhalide salts dissolved in ionic liquids should be versatile halogenating reagents, which are safer and easier to handle than the gaseous, strong oxidizers ClF or F2. Due to their high heat capacity these are good media to moderate the usually quite exothermic halogenation reactions. For the synthesis of new materials we want to use these reactive ionic liquids especially in i) 1,1-addition and 1,2-additions, ii) halogene exchange reactions, and iii) -CN to -CF3 transformation. In particular efficient synthetic routes to the highly desired weakly coordinating closo-borate and closo-carborate anions like [B12X12]2-, [CB11X12]- (X = F, Cl, Br, I) and the corresponding trifluoromethyl-substituted derivatives will be developed.

• DFG Programme: Priority Programmes
• Subproject of: SPP 1708: Material Synthesis near Room Temperature