Interstitial Bismuth Atoms in Icosahedral Rhodium Cages: Syntheses, Characterizations, and Molecular Structures of the [Bi@Rh₁₂(CO)₂₇]^3–, [(Bi@Rh₁₂(CO)₂₆)₂Bi]^5–, [Bi@Rh₁₄(CO)₂₇Bi₂]^3–, and [Bi@Rh₁₇(CO)₃₃Bi₂]^4– Carbonyl Clusters

The reaction of [Rh₇(CO)₁₆]^3– with BiCl₃ under N₂ and at room temperature results in the formation of the new heterometallic [Bi@Rh₁₂(CO)₂₇]^3– cluster in high yields. Further controlled addition of BiCl₃ leads first to the formation of the dimeric [(Bi@Rh₁₂­(CO)₂₆)₂Bi]^5– and the <i>closo</i>-[Bi@Rh₁₄­(CO)₂₇Bi₂]^3– species in low yields, and finally, to the [Bi@Rh₁₇­(CO)₃₃Bi₂]^4– cluster. All clusters were spectroscopically characterized by IR and electrospray ionization mass spectrometry, and their molecular structures were fully determined by X-ray diffraction studies. Notably, they represent the first examples of Bi atoms interstitially lodged in metallic cages that, in this specific case, are all based on an icosahedral geometry. Moreover, [Bi@Rh₁₄(CO)₂₇Bi₂]^3– forms an exceptional network of infinite zigzag chains in the solid state, thanks to intermolecular Bi–Bi distances