Synthesis and reactivity of$(\mu - H)(\mu _3 - \eta ^2 - H_2 )_4 )Os_3 (CO)_9$: An unusually reactive triosmium cluster

Abstract

The synthesis of$(\mu - H)(\mu - \eta ^2 - H_2 )_4 )Os_3 (CO)_{10}$ (4) from piperidine and Os₃(CO)₁₀(CH₃CN)₂ and its solid state structure are reported. The room temperature reactions of the decarbonylation product of4,$(\mu - H)(\mu _3 - \eta ^2 - H_2 )_4 )Os_3 (CO)_9$ (3), with P(C₆H₅)₃, CNCH₃, HCl and H₂ are reported. Overall, the products obtained closely resemble those obtained from the analogous,$(\mu - H)(\mu _3 - \eta ^2 - H_2 )_3 )Os_3 (CO)_9$ (1). The isomerizations of the phosphine addition products$(\mu - H)(\mu - \eta ^2 - H_2 )_n )Os_3 (CO)_9 P(C_6 H_5 )_3$ (n = 3,6a;n = 4,5a) have been studied by¹H-NMR techniques and the initial rearrangement was shown to be an intramolecular process. Slower conversion to the complex$(\mu - H)(\mu _3 - \eta ^2 - H_2 )_4 )Os_3 (CO)_8 P(C_6 H_5 )_3$ (8) was observed and the solid state structure of this product is reported and compared with a related compound containing an ethyl,n-propylμ ₃-imidoyl ligand. Compound4 crystallizes in the triclinic space group Pl (#2) withZ= 2, and unit cell parametersa = 9.294(3) Å,b = 15.758(5) Å,c = 7.406(2) Å,a = 81.10(2)°,β=76.47(2)°,y =74.88(2)°, andV =1013(l) ų. Least-squares refinement of 2677 reflections gave a final discrepancy factor ofR = 0.054 (R _w = 0.066). Compound8 crystallizes in the space group C2/c with unit cell parametersa = 24.818(3) Å,b = 16.389(3) Å,c = 18.111(3) Å,β= 120.94(2)°,V = 6318(4) ų, andZ = 8. Least squares refinement of 3439 reflections gave a final discrepancy factor ofR = 0.039 (R _w =0.047).