Pseudohalogen Chemistry in Ionic Liquids with Non-innocent Cations and Anions

• Applicant: Professor Dr. Axel Schulz
• Subject Area: Inorganic Molecular Chemistry - Synthesis and Characterisation
• Term: from 2014 to 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 252590704

This project describes the utilization of Ionic Liquids (ILs) with non-innocent anions and cations to synthesize new pseudohalogen borates, silicates and phosphates. As non-innocent anions are used either decomposable ions such as carbonates ([CO2(OMe)]-), borates ([B(OMe)3A]-, [B(OMe)4]-; with A = pseudohalogen, e.g. CN, SCN, N3), silicates ([Si(OMe)4A]-) and phosphates ([OP(OMe)3A]-) or the highly nucleophilic (pseudo)halides, which also form ILs with corresponding organic cations. The goal of this project is the syntheses of new (often highly labile) pseudohalogen species such as [CO2A]-, [A...H...A]-, [B(OMe)3A]-, [B(OMe)2E1A]- (E1 = halogen), [B(OMe)E2A]- (E2 = chalkogen), [A-B-E3]- (E3 = pnictogen) and salt bearing the [SiF6-n(CN)n]2- and [PF6-n(CN)n]- ions utilizing functionalized ILs for quenching or stabilizing, respectively. Non-innocent means that the used IL is both the reaction media as well as reactant. The project splits into five interacting parts: (i) Syntheses of pure pseudohalide containing ILs from ILs with decomposable anions. Preparation of pure pseudohalide containing ILs, [Cat]+A- (A = e.g. CN, SCN, N3), is well-established. Besides, the synthesis of pseudohalide containing ILs, special emphasis will be placed on the isolation of the intermediates such as [CO2A]-.(ii) Reactions of pseudohalide containing ILs with non-metal elements (e.g. P4, S8) and their oxides and sulfides. A special emphasis will be given to the solubility problem as well as the bond activation by the highly nucleophilic pseudohalides when they are part of an IL. (iii) Reactions of pseudohalide containing ILs with pure acids of pseudohalides (HA). As these ILs contain naked pseudohalides the formation of [A...H...A]- ions upon addition of the pure HA acid should be observed and the isolation attempted.(iv) Syntheses of pseudohalogen borate, silicate and phosphate species in pseudohalide containing ILs and their reaction with persilylated compounds of group 15-17.(v) Syntheses of coordination polymers utilizing cyanido(fluorido)phosphates, -arsenates and -silicates containing ILs with decomposable cations such as [nPr3NH]+.

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