Hypoelectronic isomeric diiridaboranes [(Cp*Ir)2B6H6]: the “Rule-Breakers”(Cp* = η5-C5Me5).

In an effort to synthesize supraicosahedral iridaboranes, pyrolysis of [Cp*IrCl2]2 with excess [BH3·THF] was carried out, and this synthesis afforded the isomeric iridaborane [(Cp*Ir)2B6H6] clusters 1 and 2. The geometry of 1 was determined to be dodecahedral, i.e., similar to that of [B8H8]2−, whereas 2 was found to exhibit a cluster shape that can be derived from a nine-vertex tricapped trigonal prism by removing one of the capped vertices. The calculation of a large HOMO–LUMO gap further rationalized the isocloso structures for these isomers. [ABSTRACT FROM AUTHOR]