Carborane radical anions: spectroscopic and electronic properties of a carborane radical anion with a 2n + 3 skeletal electron count.

One-electron reduction of the well-known carborane 1,2-Ph2-1,2-C2B10H10 (1) gives rise to a stable carborane radical anion ([1]-) with a true 2n + 3 cluster electron count; the geometry of ([1]-) features an elongated C...C cage distance but no significant pi-bonding interactions between the cage and the phenyl substituents.