196520-67-9Relevant academic research and scientific papers
Meyer's complex OsH2Cl2(PiPr3)2 as a precursor for the preparation of new cyclopentadienylosmium compounds
Esteruelas, Miguel A.,Lopez, Ana M.,Ruiz, Natividad,Tolosa, José I.
, p. 4657 - 4667 (2008/10/08)
The six-coordinate complex OsH2Cl2(PiPr3)2 (1) reacts with cyclopentadienylthallium to give Os(η5-C5H5)Cl(PiPr 3)2 (2). In methanol and acetone, 2 dissociates the chlorine ligand and the resulting metallic fragment is capable of activating a methyl C-H bond of a triisopropylphosphine to afford [OsH(η5-C5H5){CH2CH(CH 3)PiPr2}(PiPr3)] + (3), which can be isolated as the PF6 salt by addition of either NaPF6 or TIPF6. Treatment of a 1:10 mixture of 2 and NaBH4 in toluene with 1.0 mL of methanol affords OsH(η5-C5H5)(PiPr 3)2 (4), which by protonation with HBF4·OEt2 yields [OsH2(η5-C5H5)(P iPr3)2]BF4 (5). In pentane, complex 2 reacts with trimethyl phosphite to give Os(η5-C5H5)Cl{P(OMe)3}(P iPr3) (6). Similarly, the addition of methyl vinyl ketone and dimethyl acetylenedicarboxylate to toluene solutions of 2 produces the displacement of a phosphine ligand from 2 and the formation of Os(η5-C5H5)Cl{η2-CH 2=CHC(O)CH3}(PiPr3) (7) and Os(η5-C5H5)Cl{η2-C(CO 2CH3)≡CCO2CH3}(P i-Pr3) (8), respectively. Complex 2 also reacts with ethyl diazoacetate to give Os(η5-C5H5)Cl{η 2-(Z)-CH(CO2C2H5)=CHCO 2C2H5}(PiPr3) (9) and with 1-ethynyl-1-cyclohexanol and 2-methyl-3-butyn-2-ol to afford Os(η5-C5H5)Cl{η 2-HC≡C-C(OH)(CH2)4CH2}(P iPr3) (10) and Os(η5-C5H5)Cl{η 2-HC≡C-C(OH)(CH3)2}(PiPr 3) (11). In toluene at 85 °C, complexes 10 and 11 evolve to the corresponding alkenylvinylidene derivatives Os(η5-C5H5)Cl{=C=CH-C=CH-(CH 2)3CH2}(PiPr3) (12) and Os(η5-C5H5)Cl{=C=CH-C(CH 3)=CH2)(PiPr3) (13). Complex 13 can also be prepared by reaction of 2 with 2-methyl-1-buten-3-yne at room temperature. In this case, a π-alkyne intermediate related to 10 and 11 was not detected even at -60 °C. However, the reaction of 2 with phenylacetylene initially gives Os(η5-C5H5)Cl{η 2-HC≡CPh}(PiPr3) (14), which subsequently evolves into Os(η5-C5H5)Cl{=C=CHPh}PiPr 3) (15). Protonation of 12, 13, and 15 with HBF4 afford the carbyne derivatives [Os(η5-C5H5)-Cl{=C-CH=C(CH 2)4CH2}(PiPr3)]BF 4 (16), [Os(η5-C5H5)Cl{≡C-CH=C(CH 3)2}(PiPr3)]BF4 (17), and [Os(η5-C5H5)Cl(≡C-CH 2Ph)(PiPr3)]BF4 (18), respectively. The structure of 16 was determined by an X-ray investigation. The Os≡C bond length is 1.756(8) A?, while the Os-C-C angle is 167.8(6)°.
