Iridium cluster chemistry:: The synthesis and the solid-state structure of [Ir11(CO)23]3-

The cluster [Ir-11(CO)(23)](3-) was obtained by reaction of [Ir-10(CO)(21)](2-) and [Ir(CO)(4)](-) in refluxing MeCN, and its solid-state structure was determined on the salt [NEt4](3)[Ir-11(CO)(23)] The metallic framework of D-3h symmetry is composed by three face-fused octahedra, all sharing a common edge. The cluster contains 9 edge bridging and 14 terminal carbonyl ligands, a disposition different from that of the two isomeric forms of the isoelectronic [Rh-11(CO)(23)](3-) both having, in the solid-state, more edge-bridging COs. Naked clusters of nontransition metals, found in binary and ternary materials, such as Cs11O3, display very similar trioctahedral polyedra.