Physicochemical Properties of 20 Ionic Liquids Prepared by the Carbonate-Based IL (CBILS) Process.

Ionic liquids (ILs) are an emerging materials' class with applications in areas such as energy storage, catalysis, and biomass dissolution and processing. Their physicochemical properties including surface tension, viscosity, density and their interplay between cation and anion chemistry are decisive in these applications. For many commercially available ILs, a full set of physicochemical data is not available. Here, we extend the knowledge base by providing physicochemical properties such as density (20 and 25 °C), refractive index (20 and 25 °C), surface tension (23 °C, including polar and dispersive components), and shear viscosity (ambient atmosphere, shear rate 1-200 s-1), for 20 commercial ILs. A correlation between the crystal volume, dispersive surface tension, and shear viscosity is introduced as a predictive tool, allowing for viscosity estimation. Systematic exploration of cation/anion alkyl side chain lengths reveals the impact on the IL's physicochemical attributes. Increasing the anion's headgroup decreases surface tension up to 35.7% and consequently shear viscosity. We further demonstrate that the dispersive part of the surface tension linearly correlates with the refractive index of the ionic liquid. While we provide additional physicochemical data, the screening and modeling efforts will contribute to better structure property predictions enabling faster progress in design and applications of ILs.

Synthesis and Characterization of New Counterion-Substituted Triacylgermenolates and Investigation of Selected Metal-Metal Exchange Reactions.

The synthetic process to obtain triacylgermenolates with alternated counterions by single-electron-transfer reactions or by a direct approach is described. The formation of these derivatives was confirmed by NMR spectroscopy and UV-vis spectroscopy. Moreover, metal-metal exchange reactions of potassium-substituted triacylgermenolate 2a with MgBr2, ZnCl2, and HgCl2 are presented. Additionally, 2a was reacted with nBu4NBr, which led to the formation of ammonia-substituted triacylgermenolate 8. Furthermore, we reacted 2a with HCl/Et2O to obtain triacylgermane 9. Subsequently, we investigated the reaction of 9 with tBu2Zn and tBu2Hg. NMR spectroscopy, single-crystal X-ray crystallography, and UV-vis spectroscopy are employed for analysis of structural properties.