Synthesis and structure of [Cp Ru(CO)<inf>2</inf>(μ-H){RuFe <inf>3</inf>(CO)<inf>9</inf>}]: An unusual mixed-metal tetrahedral cluster with an exopolyhedral metal fragment

Mild pyrolysis of arachno-(Cp*RuCO)2B2H 6, 1 (Cp* = η5-C5Me5), with Fe2(CO)9 leads to the isolation of a mixed-metal tetrahedral cluster, [Cp*Ru(CO)2(μ-H){RuFe 3(CO)9}], 2, in which [Cp*RuH(CO)2] is attached to the tetrahedral cluster in an exopolyhedral manner. Cluster 2 can be viewed as 52-cve (cluster valence electron) tetrahedral cluster, in which the Ru fragment occupies the low connectivity cluster vertexes and participates in an exopolyhedral hydrogen-bridged ruthenium-ruthenium double bond. Cluster 2 has been characterized by mass spectrometry, IR, and 1H, 11B, and 13C NMR spectroscopy, and the geometric structure was unequivocally established by crystallographic analysis. © 2010 American Chemical Society.