The allenylidene complexes [M(CCCR2)(η5-C9H7)L2][PF6] (M = Ru, L = PPh3, L2 = 1,2-bis(diphenylphosphino)ethane (dppe), bis(diphenylphosphino)methane (dppm), R2 = 2 Ph (1a−c), C12H8 (2,2‘-biphenyldiyl) (2a−c); M = Os, L = PPh3, R2 = 2Ph (3), C12H8 (4)) have been prepared by reaction of the complexes [MCl(η5-C9H7)L2] with HC⋮CC(OH)R2 and NaPF6 in refluxing methanol. The crystal structures of [M(CCCPh2)(η5-C9H7)(PPh3)2][PF6]·CH2Cl2 (M = Ru (1a), Os (3)) were determined by X-ray diffraction methods. In the structures the MCCC chains are nearly linear (M−C(1)−C(2) = 168.5(5)° (1a) and 169.3(4)° (3); C(1)−C(2)−C(3) = 168.2(7)° (1a) and 168.0(5)° (3)) with MC(1) distances of 1.878(5) Å (1a) and 1.895(4) Å (3). The indenyl ligand is η5-bonded to the metal with the benzo ring orientated “cis” with respect to the allenylidene group. Extended Hückel molecular orbital calculations have been used to rationalize the preferred “cis” orientation. The reaction of [RuCl(η5-C9H7)L2] (L = PPh3, L2 = dppe, dppm) with HC⋮CCMe(OH)Ph and NaPF6 in refluxing methanol leads to the formation of the allenylidene complexes [Ru{CCC(Me)Ph}(η5-C9H7)L2][PF6] (6a−c) along with the vinylvinylidene isomers [Ru{CC(H)C(Ph)CH2}(η5-C9H7)L2][PF6] (L = PPh3 (5a), L2 = dppe (5b), dppm (5c)). Only complex 6a could be isolated by chromatography (SiO2) from these mixtures along with complex 7a obtained from the deprotonation of the vinylvinylidene complex 5a. The treatment of these reaction mixtures with potassium carbonate yields the neutral σ-enynyl derivatives [Ru{C⋮CC(Ph)CH2}(η5-C9H7)L2] (7a−c). The monosubstituted allenylidene complex [Ru{CCC(H)Ph}(η5-C9H7)(PPh3)2][PF6] (9) has been prepared by the reaction of [RuCl(η5-C9H7)(PPh3)2] with HC⋮CCH(OH)Ph and NaPF6 in methanol. Under similar reaction conditions [RuCl(η5-C9H7)L2] reacts with HC⋮CCH(OH)R and NaPF6 to afford the alkenylmethoxycarbene derivatives [Ru{C(OMe)C(H)CH(R)}(η5-C9H7)L2][PF6] (L2 = dppe, R = Ph (11b); L2 = dppm, R = Ph (11c), H (13)). [RuCl(η5-C9H7)(PPh3)2] also reacts with HC⋮CC(OH)H2 to give the hydroxyvinylidene complex [Ru{CCH(CH2OH)}(η5-C9H7)(PPh3)2][PF6] (12), which is stable toward the dehydration process.

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The treatment of the binuclear tetracarbonyl complex [Ru2{μ-(η5-C5H4)2SiMe2}(μ-CO)2(CO)2] (1) with HBF4 in dichloromethane leads to the electrophilic addition of one proton to yield the bridging hydride complex [Ru2{μ-(η5-C5H4)2SiMe2}(μ-H)(CO)4][BF4] (2). Complex 1 also reacts with Li[BHEt3] to afford the bridging methylene complex [Ru2{μ-(η5-C5H4)2SiMe2}(μ-CH2)(μ-CO)(CO)2] (3). Binuclear complexes [Ru2{μ-(η5-C5H4)2SiMe2}(X)2(CO)4] (X = Cl (4a), Br (4b), and I (4c)) have been synthesized in good yields from the reaction of complex 1 with N-chlorosuccinimide (X = Cl) and X2 (X = Br, I) in CH2Cl2. The structure of complex 4a which has been determined by X-ray crystallography shows a three-legged piano-stool geometry around each ruthenium atom linked by the bridging Me2Si(η5-C5H4)2 group. The cyclopentadienyl rings which are coordinated in a η5 fashion are rotated in opposite directions around the Si−C(bridgehead) bond, leading to the trans arrrangement of the metal fragments and giving rise to a long ruthenium−ruthenium distance (6.120(6) Å). Complex 4c has been used as a precursor in a series of halide and carbonyl substitution reactions. The reaction of 4c with the cuprate derivative Li[CuMe2] in THF leads to the exchange of both iodide anions to give the dimethyl complex [Ru2(μ-(η5-C5H4)2SiMe2}(CH3)2(CO)4] (5). The treatment of complex 4c with AgBF4 in refluxing acetonitrile leads to halide abstraction to afford the cationic complex [Ru2{μ-(η5-C5H4)2SiMe2}(CO)4(NCMe)2][BF4]2 (9). The analogous reaction of complexes 4a−c with AgBF4 in CH2Cl2 or acetone at room temperature gives the cationic double-bridged derivatives [Ru2{μ-(η5-C5H4)2SiMe2)}(μ-X)(CO)4][BF4] (10a − c). The X-ray crystal structure of 10b shows the two ruthenium moieties bridged by a halogen atom, forcing a cisoid arrangement in the molecule. Irradiation of a solution of 4c and PCy3 in THF leads to carbonyl substitutions to yield the monocarbonyl complex [Ru2{μ-(η5-C5H4)2SiMe2}(I)2(CO)2(PCy3)2] (6c). Analogous isocyanide carbonyl substituted complexes [Ru2{μ-(η5-C5H4)2SiMe2}(I)2(CNR) x (CO)4 - x ] (R = CH2Ph, x = 1 (7a), x = 2 (7b), x = 3 (7c), x = 4 (7d); R = Cy, x = 1 (8a), x = 2 (8b), x = 3 (8c), x = 4 (8d)) have been obtained by UV irradiation of 4c and the corresponding isocyanide in THF, depending on the ligand:complex ratio.

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