Superacidity of Boron Acids H2(B12X12) (X=Cl, Br)


  • We thank Prof. Dr. E. S. Stoyanov for invaluable assistance with the IR measurements and their interpretation and Dr. Bruno Donnadieu for X-ray crystallographic support. This work was supported by the National Science Foundation (CHE-039878 to C.A.R. and an NSF Graduate Fellowship to A.A.).


Acid remarks: The anhydrous diprotic boron acids H2(B12X12) (X=Cl, Br; see picture, B orange, X green) are the first examples of diprotic superacids and may be the strongest acids yet isolated. Both protons protonate benzene to give benzenium ion salts that are stable at room temperature. These acids owe their existence to the stability of the icosahedral B12 cluster with its dinegative charge buried beneath a layer of halide substituents.

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