Ionic liquids (ILs) are of high interest due to their interesting physical properties that lead to a vast series of potential applications. Among the known ionic liquids, those with boranate – that is, hydridoborate-based – anions (BILs) are an interesting and hitherto underdeveloped area of chemical research.
Ingo Krossing and colleagues, University of Freiburg, Germany, realized the first syntheses of pure ILs with [BH4]− and [B3H8]− ions as one-step reactions.
They achieved the facile synthesis of halide-free BILs with different organic cations and the two hydridoborate anions [BH4]− and [B3H8]−. The solvents NH3 and CH2Cl2 as well as the starting materials for the preparation of the [BH4]− ILs are cheap and the converged preparation is easy to handle.
They also examined the mechanism of the reaction in greater detail and suggest possible paths supported by many NMR spectroscopic experiments, IR and Raman spectroscopy, PXRD, and quantum chemical calculations with inclusion of solvation effects in CH2Cl2, and presented a plausible exergonic route.
All synthesized ILs are well soluble in CH2Cl2. The procedure gives clean products with correct elemental analyses.
These boranate ILs are suitable reagents for synthesis and have a potential for redox shuttling and storage/release of H2.
- Synthesis and Characterization of Boranate Ionic Liquids (BILs),
Mara Bürchner, Anna M. T. Erle, Harald Scherer, Ingo Krossing,
Chem. Eur. J. 2012.