When the Ferrocene Analogy Breaks Down: Metallocene Transmetallation Chemistry.

Ferrocene 1 and its dianionic Fe(bis)(dicarbollide) analogue 2 are classical compounds that display unusual stability. These compounds are not known to undergo transmetallation chemistry of the Fe-center and have been used extensively as chemical building blocks with consistent integrity. In this manuscript we describe the preparation of a charge compensated Fe(bis)(dicarbollide) species 3 Fe and its unprecedented transmetallation chemistry to Ir.

Fusing 10-vertex -carborane anions with N-heterocyclic carbenes.

Discovered by Knöth in 1964, the 10-vertex -carborane anion [HCBH] is a classical bicapped square antiprism that contains an unusual pentacoordinate carbon center. Compared to its larger icosahedral cousin [HCBH], few investigations have been made into its use as a weakly coordinating anion or as a ligand substituent. Here we show that it is possible to prepare both a dianionic N-heterocyclic carbene (NHC) Li adduct as well as a trianionic C-2, C-5 dilithio species featuring two 10-vertex carborane anion substituents.