Collect. Czech. Chem. Commun. 1999, 64, 819-828

A Novel Heterooctametallic Metallacarborane Tetramer

Keith G. Parker, J. Monte Russell, Michal Sabat and Russell N. Grimes*

Department of Chemistry, University of Virginia, Charlottesville, VA 22901, U.S.A.


The synthesis and X-ray crystal structure determination of [(2,3-Et2C2B4H4)Co(2,3-Et2C2B3H3-5-Bu)Ru]4 (3) are reported. Complex 3 was obtained serendipitously in low yield from a reaction of [(η4-C8H12)Ru(MeCN)4][PF6]2 with the (Et2C2B4H4)Co(Et2C2B3H3Bu)2- anion in THF solution at room temperature. The molecular geometry of 3, isolated as a yellow-orange crystalline solid, is without precedent in boron cluster chemistry and consists of an array of four (Et2C2B4H4)Co(Et2C2B3H3Bu)Ru units linked via intercluster Ru-B covalent bonds. Each cluster moiety contains a double-decker (C2B4)Co(C2B3) sandwich with an exo-polyhedral ruthenium atom occupying a "wedging" position in which it is bound to the C2B3 and the C2B4 ligands as well as to a neighboring sandwich unit.

Keywords: Boranes; Carboranes; Metallacarboranes; Ruthenium; Cobalt clusters; Sandwich complexes.