Lithium and sodium salts of the closo-[CB₁₁H₁₂]⁻ anion can be useful as electrolytes for all-solid-state batteries as they provide high ionic conductivity. The closo-carbadodecaborate anions in these salts are weakly coordinating, which is ideal for the movement of cations such as Na⁺ and Li⁺. They also have a delocalized electronic structure, making them chemically stable. Existing syntheses of the closo-[CB₁₁H₁₂]⁻ anion can be complex, expensive, and require dangerous reagents that hamper the commercial use of closo-carbadodecaborate anions in electrolytes.

Mark Paskevicius, Curtin University, Perth, Australia, and colleagues have used cost-effective common laboratory reagents to synthesize the closo-[CB₁₁H₁₂]⁻ anion while avoiding reagents like decaborane, NaH, and CF₃SiMe₃, which can be toxic, flammable, and/or expensive. Instead of using decaborane as a precursor to synthesize the closo-[CB₁₁H₁₂]⁻ anion, the team used nido-[B₁₁H₁₄]^– as a precursor. The team deprotonated the anion of Me₃NH[B₁₁H₁₄] using NaOH and K₂CO₃ and reacted it with chloroform to give closo-[CB₁₁H₁₂]⁻.

Using this method on a gram scale, the team obtained a yield of 40 %, compared with 95 % for previously known approaches. However, the method avoids the use of dangerous substances and the cost of the reagents is significantly lower. The developed method to synthesize Me₃NH[CB₁₁H₁₂] could be accessible to any chemist and further the commercial application of closo-[CB₁₁H₁₂]⁻ salts for all-solid-state batteries.

• Synthesis of closo-CB₁₁H₁₂^– Salts Using Common Laboratory Reagents,
  Amanda Berger, Craig E. Buckley, Mark Paskevicius,
  Inorg. Chem. 2021.
  https://doi.org/10.1021/acs.inorgchem.1c01896