Synthesis and structure of a family of rhodium polystannide clusters [Rh@Sn10]3–, [Rh@Sn12]3–, [Rh2@Sn17]6– and the first triply-fused stannide, [Rh3@Sn24]5–

Abstract

Through relatively subtle changes in reaction conditions, we have been able to isolate four distinct Rh/Sn cluster compounds, [Rh@Sn₁₀]³⁻, [Rh@Sn₁₂]³⁻, [Rh₂@Sn₁₇]⁶⁻ and [Rh₃@Sn₂₄]^5–, from the reaction of K₄Sn₉ with [(COE)₂Rh(μ-Cl)]₂(COE = cyclooctene). The last of these has a hitherto unknown molecular topology, an edge-fused polyhedron containing three Rh@Sn₁₀ subunits, and represents the largest endohedral Group 14 Zintl cluster yet to have been isolated from solution. DFT has been used to place these new species in the context of known cluster chemistry. ESI-MS experiments on the reaction mixtures reveal the ubiquitous presence of {RhSn₈} fragments that may play a role in cluster growth.