Mixed-ligand di-µ-chloro-bridged Rhodium Dimers as Key Intermediates in the Synthesis of Acyclic (p-allyl)-closo-rhodacarboranes

The mixed-ligand di-m-chloro-bridged rhodium dimers [(?²-C₈H₁₄)(?⁴-2-methylbuta-1,3-diene)Rh(µ-Cl)]₂ and [(?²-C₈H₁₄)(?⁴-2,3- dimethylbuta-1,3-diene)Rh(µ-Cl)]₂ were synthesized and characterized. These compounds are key precursors in the preparative syn- thesis of the acyclic (p-allyl)-closo-rhodacarborane complexes [3-{p-(R”-allyl)}-1-R-2-R’-closo-3,1,2-RhC₂B₉H₉], which were obtained earlierviathe one-pot metallation of the K⁺ salts of the [7-R-8-R’-nido-7,8-C₂B₉H₁₀]^– anions with [(?²-C₈H₁₄)₄Rh₂(µ-Cl)₂] in the presence of substituted buta-1,3-diene ligands.