Between Localization and Delocalization: Ru(cod)2+ Units in the Zintl Clusters [Bi9{Ru(cod)}2]3− and [Tl2Bi6{Ru(cod)}]2

Reactions of [K(crypt‐222)]2(TlBi3)⋅0.5 en (1 b) with [Ru(cod)(H2CC(Me)CH2)2] (A) in 1,2‐diaminoethane (en) led to the formation of two compounds with new bismuth‐rich cluster anions, [K(crypt‐222)]3[Bi9{Ru(cod)}2]⋅1.5 en (2) and [K(crypt‐222)]2[Tl2Bi6{Ru(cod)}]⋅2 tol (3), alongside the salt of a binary nido cluster, [K(crypt‐222)]3(Tl4Bi5)⋅2 en (4). The anions in 2 and 3 are two further examples of rare heterometallic clusters containing Ru atoms. As one cod ligand is retained on each Ru atom in both clusters, the anions may be viewed as intermediates on the way towards larger, ligand‐free intermetalloid clusters. Quantum‐chemical studies provided insight into the bonding situation in these clusters. According to these studies, the anion of 2 features both electron‐precise and electron‐deficient parts. Electrospray ionization mass spectrometry analysis indicated that the clusters undergo stepwise fragmentation. A little bit of each: DFT studies confirm a hybrid bonding situation in [Bi9{Ru(cod)}2]3− with both localized and delocalized bonds. This cluster and [Tl2Bi6{Ru(cod)}]2− were obtained upon reaction of the binary Zintl anion (TlBi3)2− with [Ru(cod)(H2CC(Me)CH2)2]. Both clusters are rare examples of Zintl anions comprising Ru atoms and illustrate the electronic flexibility of Group 15 polyanions with (pseudo)atoms of other groups.