Synthesis and Structure of [Cp*Ru(CO)2(μ-H){RuFe3(CO)9}]: An Unusual Mixed-Metal Tetrahedral Cluster with an Exopolyhedral Metal Fragment

Mild pyrolysis of arachno-(Cp*RuCO)2B2H6, 1 (Cp* = η5-C5Me5), with Fe2(CO)9 leads to the isolation of a mixed-metal tetrahedral cluster, [Cp*Ru(CO)2(μ-H){RuFe3(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.