Chalkogenide-based Ionic Liquids in the Synthesis of Metal Chalcogenide and Interchalcogenide Materials near Room Temperature

• Applicant: Professor Dr. Jörg Sundermeyer
• Subject Area: Solid State and Surface Chemistry, Material Synthesis
• Term: from 2017 to 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 376983425

The project investigates the application of ionic liquids (IL) comprising chalcogen-based anions of the hydrochalcogenide [EH], trimethylsilylchalcogenide [E-TMS] or polychalcogenide type [Ex] (E = S, Se, Te) in the synthesis of selected 2D- and 3D-metal chalcogenide or poly- and interchalcogenide materials. This research will demonstrate a clear benefit of using such highly reactive synthons for chalcogen transfer, that combine easy access, highest purity, perfect solubility in organic co-solvents, low melting points (in some cases) and highest reactivity towards electrophiles and Lewis acids. A first strategy follows up protolysis reactions of selected metal organyls and amides in ionic liquids Cat [EH] (E = S, Se), a second complementary strategy the anion metathesis of metal halides dissolved in Cat [E-TMS] and Cat [EH] ILs. In this respect, selected metal precursor compounds of the p-block, Ga(III), In(III), In(II) and Sn(II), are planned to be compared in their reactivity pattern with selected precursors of the f-block elements, Ln(II) and Ln(III). New classes of thermally labile chalcogenido organometallates [(RxM)yEz]n- (M = Ga, In, La and Ln; E = S, Se) and of trimethylsilylchalcogenido-metallates [M(E-TMS)4]- (M = Ga, In, La) will be accessible. They are labile intermediates in their conversion into semiconducting materials ME, M2S3 and ME2 at room temperature or slightly above. Room temperature IL reactions allow the isolation of novel tin(II) and tin(IV) precursor compounds, Cat[SnE2] and Sn(E-TMS)4 (E = S, Se), awaiting their condensation to SnE and SnE2 semiconducting materials. Reaction of [NH4]2[MoS4] with methylcarbonate ILs Cat[MeCO3] offers access to intermediates Cat2[MoS4], that are planned to be converted to MoS2 via two strategies: 1) thermolyis in a IL flux and 2) reaction with electrophiles followed by reductive elimination of disulfides RSSR. A third strategy investigates the thiolysis of [MoX4] complexes in Cat[SH] or Cat[S-TMS] ILs. Finally, the benefit of chalcogenide ILs in low-temperature syntheses of chalcogen-rich polychalcogenide, interchalcogenide and interchalcogen materials is planned to be explored.

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