| Abstract: | Reaction of Cyclopentadienyl Substituted Molybdenum(V) Tetrachlorides with LiPH(2,4,6-Bu  C6H2) and KPPh2(Dioxane)2. Crystal Structures of Cp0Mo(μ? Cl)2]2 and Cp  Mo2(μ? Cl)3(μ? PPh2)] (Cp0 = C5Me4Et) The reaction of Cp0Mo(CO)3]2 (Cp0 = C5Me4Et) and Cp′Mo(CO)3]2 (Cp′ = C5H4Me) with PCl5 in CH3CN furnishes the Mo(V) complexes Cp0MoCl4(CH3CN) 1 and Cp′MoCl4(CH3CN) 2 in good yields. While 1 and 2 are reduced by LiPH(2,4,6-Bu C6H2) to the Mo(III) complexes Cp0Mo(μ? Cl)2]2 3 and Cp′Mo(μ? Cl)2]2 4 , the reaction of 1 with KPPh2(dioxane)2 yields the reduction/substitution product Cp Mo2(μ? Cl)3(μ? PPh)] 5 in low yield. 1 – 4 were characterized spectroscopically (i.r., mass, 3 and 4 also n.m.r.). An X-ray crystal structure determination was carried out on 3 and 5. 3 crystallizes in the triclinic space group P1 (No. 2) with a = 8.278(4), b = 12.508(7), c = 12.826(7) Å, α = 86.78(5), β = 81.55(2), γ = 75.65(4)°, V = 1 272.4 Å3 and two formula units in the unit cell (data collection at ? 67°C, 4 255 independent observed reflections, R = 2.9%); 5 crystallizes in the triclinic space group P1 (No. 2) with a = 11.536(8), b = 12.307(9), c = 13.157(9) Å, α = 91.41(6), β = 100.42(5), γ = 112.26(6)°, V = 1 688.7 Å3 and two formula units in the unit cell (data collection at ? 60°C, 6 147 independent observed reflections, R = 4.9%). The crystal structure of 3 shows the presence of centrosymmetric dimeric molecules with four bridging chloro ligands. In 5, two Mo atoms are bridged by three chloro ligands and one PPh2 ligand. The Mo? Mo bond length in 3 and 5 (2.600(2), 2.596(2) Å and 2.6388(8) Å) is in agreement with a Mo? Mo bond. |
