The five-coordinate complex [RuHCl(CO)(PPri 3)2] (1) reacts with cyclopentadiene in methanol under reflux to give [RuH(η5-C5H5)(CO)(PPri 3)] (2) and [HPPri 3]Cl. The protonation of 2 in dichloromethane-d 2 leads to the dihydrogen complex [Ru(η5-C5H5)(η2-H2)(CO)(PPri 3)]BF4 (3) in equilibrium with traces of the dihydrido tautomer [RuH2(η5-C5H5)(CO)(PPri 3)]BF4 (4). The reaction of 2 with HBF4·Et2O in acetone affords the solvated complex [Ru(η5-C5H5)(CO){η1-OC(CH3)2}(PPri 3)]BF4 (5), which reacts with CO, dimethyl acetylenedicarboxylate, and NaCl to give [Ru(η5-C5H5)(CO)2(PPri 3)]BF4 (6), [Ru(η5-C5H5){η2-C2(CO2CH3)2}(CO)(PPri 3)]BF4 (7), and [Ru(η5-C5H5)Cl(CO)(PPri 3)] (8), respectively. Complex 5 also reacts with alkyn-1-ols. The reaction with 1,1-diphenyl-2-propyn-1-ol leads to the allenylidene complex [Ru(η5-C5H5)(CCCPh2)(CO)(PPri 3)]BF4 (9), which affords [Ru(η5-C5H5){C(OH)CHCPh2}(CO)(PPri 3)]BF4 (10) by reaction with water. 10 is converted into the acyl derivative [Ru(η5-C5H5){C(O)CHCPh2}(CO)(PPri 3)] (11), when a CH2Cl2 solution of 10 is passed through an Al2O3 column. The structure of 11 was determined by an X-ray investigation. The reaction of 5 with 2-propyn-1-ol leads to the α,β-unsaturated hydroxycarbene complex [Ru(η5-C5H5){C(OH)CHCH2}(CO)(PPri 3)]BF4 (12). Similarly to 10, 12 is converted into [Ru(η5-C5H5){C(O)CHCH2}(CO)(PPri 3)] (13), when the solutions of 12 are passed through an Al2O3 column. Treatment of 5 with 1-ethynyl-1-cyclohexanol leads to a mixture of organometallic compounds including [Ru(η5-C5H5){C(OH)CHC(CH2)4CH2}(CO)(PPri 3)]BF4 (14). Chromatography of the mixture affords [Ru(η5-C5H5){C(O)CHC(CH2)4CH2}(CO)(PPri 3)] (15) and [Ru(η5-C5H5){C⋮CCCH(CH2)3CH2}(CO)(PPri 3)] (16). 9 reacts with alcohols and thiols to give [Ru(η5-C5H5){C(ER)CHCPh2}(CO)(PPri 3)]BF4 (ER = OMe (17), OEt (18), SPrn (21)), which by treatment with NaOMe afford [Ru(η5-C5H5){C(ER)CCPh2}(CO)(PPri 3)] (ER = OMe (19), OEt (20), SPrn (22)). Similarly, the reaction of 9 with benzophenone imine leads to [Ru(η5-C5H5){C(CHCPh2)NCPh2}(CO)(PPri 3)]BF4 (23), which by reaction with NaOMe gives [Ru(η5-C5H5){C(NCPh2)CCPh2}(CO)(PPri 3)] (24). The structure of 23 was also determined by an X-ray investigation. The CN bond lengths are 1.283(9) and 1.252(9) Å, while the C−N−C angle is 149.9(6)°.

The reaction of [OsHCl(CO)(PPri 3)2] (1) with cyclopentadiene in refluxing methanol affords the novel cyclopentadienylosmium(II) complex [OsH(η5-C5H5)(CO)(PPri 3)] (2). Reaction of 2 with CCl4 in pentane gives the chloro complex [Os(η5-C5H5)Cl(CO)(PPri 3)] (3). The protonation of 2 with HBF4·Et2O leads to the trans-dihydridoosmium(IV) complex [OsH2(η5-C5H5)(CO)(PPri 3)]BF (4). Treatment of the chloro complex 3 with AgBF4 followed by the terminal alkyne phenylacetylene or 1-ethynyl-1-cyclohexanol gives the stable vinylidene [Os(η5-C5H5){CC(H)Ph}(CO)(PPri 3)]BF4 (5) or vinylvinylidene [Os(η5-C5H5){CC(H)CCH(CH2)3CH2}(CO)(PPri 3)]BF4 (6), respectively.

EHT-MO Calculations on the model cation [Ru(η5-C5H5)(CCCH2)(CO)(PH3)]+ (1a) suggest that 23% and 31% of the LUMO and 26% of the HOMO of [Ru(η5-C5H5)(CCCPh2)(CO)(PiPr3)]BF4 (1) are located on Cα, Cγ, and Cβ of the allenylidene ligand, respectively. On the basis of these results, we report a new synthetic strategy for the preparation of compounds resulting from the formal addition of phenylacetylene, acetone, and methane to the allenylidene of 1. Treatment of 1 with LiC⋮CPh leads to the allenyl complex Ru(η5-C5H5){C(C⋮CPh)CCPh2}(CO)(PiPr3) (2) and the alkynyl derivative Ru(η5-C5H5){C⋮C−C(Ph)2C⋮CPh}(CO)(PiPr3) (3). The reaction of 2 with HBF4 affords the substituted carbene compound [Ru(η5-C5H5){C(C⋮CPh)CHCPh2}(CO)(PiPr3)]BF4 (4), which is a result from the formal addition of phenylacetylene to the Cα−Cβ double bond of the allenylidene of 1. The molecular structure of 4 has been determined by X-ray crystallography. The geometry around the ruthenium center is close to octahedral with the cyclopentadienyl ligand occupying three sites of a face. The RuC bond length is 2.004(5) Å. In the presence of KOH, complex 1 reacts with acetone to give Ru(η5-C5H5){C⋮C−C(Ph)2CH2C(O)CH3}(CO)(PiPr3) (5). The reaction of 5 with HBF4 leads to the unsaturated cyclic carbene Complex 5 also reacts with 2 equiv of CF3CO2D to and CF3CO2H, and the reaction of Ru(η5-C5H5){C⋮C−C(Ph)2CD2C(O)CD3}(CO)(PiPr3) (5- d 5 ) with 2 equiv of HBF4 and DBF4. On the basis of these isotope labeling experiments, the mechanism for the addition of acetone to the allenylidene ligand of 1 is discussed. Complex 1 also reacts with Na(acac) and CH3Li. The reaction with Na(acac) leads to Ru(η5-C5H5){C⋮C−C(Ph)2CH[C(O)CH3]2}(CO)(PiPr3) (7), while the treatment of 1 with CH3Li gives a mixture of Ru(η5-C5H5){C(CH3)CCPh2}(CO)(PiPr3) (8) and Ru(η5-C5H5){C⋮C−C(Ph)2CH3}(CO)(PiPr3) (9). Complex 9 reacts with HBF4 to afford [Ru(η5-C5H5){CCHC(Ph)2CH3}(CO)(PiPr3)]BF4 (10), which is a result of the formal addition of a C−H bond of methane to the Cβ−Cγ double bond of the allenylidene of 1.