[GeRu 6 (CO) 18 HI]: A Germanium-Centered Ruthenium Carbonyl Cluster with Aromatic Ring Current.

The carbonyl cluster compound [GeRu 6 (CO) 18 HI] is unique in regard to its structure and bonding with a GeRu 6 cluster core, a planar GeRu 4 HI unit, extensive multi-center bonding, and an aromatic ring current similar to benzene (9-10 nA T -1 ). The open-shell cluster core is a Ge-centered five-membered Ru 4 (Ru 2 ) ring with CO ligands and an additional H and I atom, each bridging two Ru atoms on opposite sides of the cluster core. The compound is prepared at 130 °C in a weakly-coordinating ionic liquid.