Collect. Czech. Chem. Commun. 2002, 67, 769-782

Chemistry on the Rhodacarborane Cluster [9,9-(PPh3)-nido-9,7,8-RhC2B8H11]: Formation of Bidentate Phosphine and Bimetallic Derivatives

Oleg Volkov, Nigam P. Rath and Lawrence Barton*

Department of Chemistry, University of Missouri-St. Louis, St. Louis, MO 63121, U.S.A.


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(dppm) to afford [9,9-(dppm-κ2P)-9-(dppm-κP)-nido-9,7,8-RhC2B8H11] (3), in which the Rh-bonded PPh3 ligands have been replaced by two dppm ligands, one in a bidentate mode and the second in a unidentate mode with a free PPh2 end.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.