Chemistry of the three-dimensionally aromatic

Abstract: After a brief introduction to the electronic structure of the three-dimensionally aro-matic icosahedral closo-monocarbadodecaborate anion CB11H12–, some recent results for its permethylated version, CB11Me12 – and three highly reactive electroneutral analogs are pre-sented and discussed. These are the radical CB11Me12•, the boronium ylide CB11Me11 with a naked boron vertex, and the isomeric carbonium ylide with a naked carbon vertex. These ylides are probably better viewed as unusual types of singlet borylene and carbene, respec-tively