[C2B10][B12] double cage boron compounds—a new approach to the synthesis of water-soluble boron-rich compounds for BNCT

A new approach in the synthesis of water-soluble boron-rich compounds was proposed. The closo-dodecaborate cage is used as a hydrophilic substitutent providing for the water-solubility of the molecule whereas the carborane cage can be used for attachment to biomolecules using earlier developed methods. The double-cage molecules [o-, m-, and p-CB10H10C(CH2)4OB12H11]2− were prepared by the reaction of the tetramethylene oxonium derivative of the closo-dodecaborate anion, [B12H11O(CH2)4]−, with the corresponding lithiated carboranes. The compounds obtained have doubled the boron contents and could serve for the synthesis of agents for boron neutron capture therapy (BNCT).