STRUCTURAL AND SPECTROSCOPIC STUDIES ON THE TRINUCLEAR CLUSTERS RE3CL9(PME3)3 AND RE3CL9(ETA-1-PH2PCH2PPH2)3

The reactions of the trinuclear cluster Re3Cl9 with various phosphine ligands in ethanol have been used to prepare the new complexes Re3Cl9(PMe2Ph)3, Re3Cl9(η1-dppm)3, Re3Cl9(dmpm)1.5, Re3Cl9(η1-arphos)3 and Re3Cl9(arphos)1.5, where dppm = Ph2PCH2PPh2, dmpm = Me2PCH2PMe2 and arphos = Ph2PCH2CH2AsPh2. The 1H and 31P{1H} NMR spectra of several of these complexes and of Re3Cl9(PMe3)3 and Re3Cl9(PMePh2)3 are described, including studies of the dissociative ligand exchange in Re3Cl9(η1-dPPM)3. The structures of Re3Cl9(PMe3)3 and Re3Cl9(η1-dppm)3 have been established by X-ray crystallography. Crystallographic data for Re3Cl9(PMe3)3: hexagonal space group P63/m, a = b = 11.614(1), c = 11.209(2) Å, α = β = 90, γ = 120°, V = 1309.4(5) Å 3 and Z = 2. The structure was refined to R = 0.038 (Rw = 0.064) for 524 data with I > 3.0σ(I). Crystallographic data for Re3Cl9(η1-dppm)3 · C7H8: triclinic space group P1, a = 11.883(3), b = 18.233(4), c = 20.102(5) Å, α = 103.32(1), β = 99.18(1), γ = 95.88(1)°, V = 4139(3) Å3 and Z = 2. The structure was refined to R = 0.039 (Rw = 0.050) for 7190 data with I > 3.0σ(I). Both structures resemble that of the previously reported Re3Cl9(PEt2Ph)3, with Re Re double bond distances spanning the narrow range of 2.471(1)-2.488(1) Å. The Re P bond lengths are 2.634(4) Å for the Me3P complex, and between 2.693(3) and 2.727(3) Å for Re3Cl9(η1-dppm)3; the presence of three monodentate dppm ligands is confirmed in the latter structure. © 1990.