REACTIONS OF ALKYNES WITH COORDINATIVELY UNSATURATED (ETA-5-C5ME5)RU DERIVATIVES - X-RAY CRYSTAL-STRUCTURES OF (ETA-5-C5ME5)CL2RU(ETA-2-N-4-MU-2-C4H4)RU(ETA-5-C5ME5) AND (ETA-5-C5ME5)3RU3(MU-2-CL)2(MU-3-CL)(ETA-2-MU-2-HC=CSIME3)

Reaction of acetylene with Cp*Ru(PiPr3)Cl or [Cp*Ru(µ3-Cl)]4 (Cp* = η5-C5Me5) gives good yields of the dinuclear ruthenacyclopentadiene complex Cp*Cl2Ru(η2:η4-µ2-C4H4)RuCp* (1). Compound 1 crystallizes in space group P1, with a = 8.673 (6) Å, b = 9.632 (7) Å, c = 16.17 (1) Å, α = 96.72 (4)°, β = 92.39 (4)°, γ = 95.95 (4)°, V = 1332 (2) Å3, Z = 2, RF = 4.42%, and RwF = 6.53%. Alkylation of 1 with MeMgBr affords the dimethyl complex Cp*Me2Ru(η2:η4-µ2-C4H4)RuCp* (2). Reaction of [CP*Ru(µ3-Cl)]4 with 8 equiv of Me3SiC≡CH produces the cyclobutadiene complex Cp*Ru[η4-C4H2(SiMe3)2]Cl (3) as the major product (67% yield). A minor product in this reaction, formed in 5% yield, is a ruthenacyclopentadiene complex analogous to 1, Cp*Cl2Ru[η2:η4-µ2-C4H2(SiMe3)2]RuCp* (4). This species was characterized in solution by NMR spectroscopy. If [CP*Ru(µ3-Cl)]4 is allowed to react with a limited amount of Me3SiC≡CH (ca. 1 equiv), a triruthenium cluster containing one alkyne ligand may be isolated in high yield. This compound, Cp*3Ru3(µ2-Cl)2(µ3-Cl)(η2-µ2-HC=CSiMe3) (5), is unstable in solution but was characterized in the solid state by X-ray crystallography. Compound 5 crystallizes in space group P21/n, with a = 12.568 (6) Å, b = 17.195 (9) Å, c = 18.307 (9) Å, β = 96.46 (3)°, V = 3931 (3) Å3, Z = 4, RF = 4.21%, and RwF = 6.74%. Finally, [CP*Ru(µ3-Cl)]4 and dimethyl acetylenedicarboxylate (DMAD) react to give a diruthenium complex containing DMAD and C6(CO2Me)6 ligands, Cp*2Ru2Cl2(MeO2CC≡CCO2Me)[C6(CO2Me)6] (6). Possible structures for this species are discussed. © 1990, American Chemical Society. All rights reserved.