Synthesis, reactivity, and X -ray crystal structures of [Os 6 Pt 2 H 2 (CO) 16 (µ-C 8 H 10 )(C 8 H 12 )]·CH 2 Cl 2 and [Os 6 H(CO) 16 (µ-C 8 H 11 )]. Model compounds for C–H activation

The reaction of [Os6(CO)16(NCMe)2] with [Pt(C8H12)2](C8H12= cyclo-octa-1,5-diene) results in the formation of [Os6Pt2H2(CO)16(µ-C8H10)(C8H12)](1). The geometry of (1) may be derived from that of [Os6(CO)18] by bridging one edge of the central Os tetrahedron with one Pt atom of the dimer unit Pt2(µ-C8H10)(C8H12). One C8H12 group has been dehydrogenated to C8H10 and the two resulting hydride ligands are terminally bound to different metals of the Os6 core. The C8H10 ligand is bound in an η3-ally1 fashion to one Pt atom and by an η2-olefinic bond and σ-alkyl bond to the second Pt atom. Upon heating in toluene, complex (1) rearranges to the known complex [Os6Pt2(CO)16(C8H12)2](3). Complex (3) is without hydride ligands and possesses a geometry of two edge-fused Os tetrahedra, one of which is Pt-bicapped. The complex [Os6H(CO)16(µ-C8H11)](2) was isolated from the reaction of [Os6H(CO)16(NCMe)2] with C8H12. Complex (2) has the bicapped tetrahedral geometry of [Os6(CO)18] with the µ-C8H11 group bridging two Os atoms of the central tetrahedron. The hydride ligand caps a triangulated Os face. This complex reacts with CO to afford the parent cluster [Os6(CO)18].