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Abstract

The electronically unsaturated rhodacarborane [9,9-(PPh₃)₂-nido-9,7,8-RhC₂B₈H₁₁] (1), reacts with Ph₂PCH₂PPh₂ (dppm) to afford [9,9-(dppm-κ²P)-9-(dppm-κP)-nido-9,7,8-RhC₂B₈H₁₁] (3), in which the Rh-bonded PPh₃ ligands have been replaced by two dppm ligands, one in a bidentate mode and the second in a unidentate mode with a free PPh₂ end. The structure of 3 is similar to the related, and isoelectronic, species [8,8-(dppm-κ²P)-8-(dppm-κP)-nido-8,7-RhSB₉H₁₀] (4), but with a difference in the orientation of the ligands. Reaction of 1 with Ph₂P(CH₂)₂PPh₂ (dppe) affords a species tentatively identified as [9,9-(dppe-κ²P)-9-(dppe-κP)-nido-9,7,8-RhC₂B₈H₁₁] (5). If allowed to react with [Ru(η⁶-p-cym)Cl₂]_2, (3) affords [9,9-{Ru(η⁶-p-cym)dppm-κ²P-(μ-Cl)₂}-nido-9,7,8-RhC₂B₈H₁₁] (6) containing the group [(μ-Cl)₂Ru(η⁶-p-cym)dppm] that coordinates in a multidentate mode to Rh. Compounds 3 and 6 are characterized by ¹¹B, ¹H and ³¹P NMR spectroscopy, elemental analysis and X-ray structure determinations.

Keywords: Carboranes; Metallacarboranes; Bidentate ligands; Rhodium; Ruthenium; Crystal structures; NMR ¹H, ¹¹B, ³¹P.

References: 40 live references.