[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.