A Topological Link between Lanthanide and Alkali‐Metal Clusters: Face‐Sharing Gadolinium Octahedra Centered by Endohedral Iridium Atoms in {Ir 3 Gd 11 }Br 15

The oligomeric cluster complex {Ir 3 Gd 11 }Br 15 was first obtained from a reaction of Gd, GdBr 3 and Ir in a 3:4:1 molar ratio at 1123 K. The crystals belong to the hexagonal space group P6 3 / m with lattice parameters a = 1276.79(14) pm and c = 1286.92(16) pm. The structure features isolated {Ir 3 Gd 11 } cluster trimers, which are built up by three face‐sharing gadolinium octahedra each centered by an iridium atom. The endohedral iridium atoms form a triangle with Ir–Ir distances of 295.51(11) pm. Thus, the {Ir 3 Gd 11 } cluster is topologically equivalent to the suboxide {O 3 Cs 11 }. The {Ir 3 Gd 11 } clusters are encapsulated in a coordination sphere of 30 bromide ions, which act as bridging ligands according to the formulation {Ir 3 Gd 11 }Br i–i 12/2 Br i–a 9/2 Br a–i 9/2 . In {Ir 3 Gd 11 }Br 15 there are 45 electrons present for intracluster bonding.