713528-58-6Relevant articles and documents
Synthesis and reactivity of osmium complexes containing a cyclopentadienyl ligand with a pendant phosphine donor group
Esteruelas, Miguel A.,Lopez, Ana M.,Onate, Enrique,Royo, Eva
, p. 3021 - 3030 (2004)
The unsaturated six-coordinate complex OsH2Cl2(P iPr3)2 (1) reacts with Li[C5H 4(CH2)2PPh2] to give [OsH 2{η5-C5H4(CH2) 2PPh2}(PiPr3)]Cl (2). This dihydride is fairly acidic and can be deprotonated with KOH in methanol. The reaction of the resulting monohydride OsH-{η5-C5H 4(CH2)2PPh2}(PiPr 3) (3) with chloroform affords Os{η5-C 5H4(CH2)2PPh2}Cl(P iPr3) (4). The extraction of the chloride ligand with TIPF6 causes the selective C-H activation of one of the methyl groups of the triisopropylphosphine ligands to give [{CH2CH(CH 3PiPr2}OsH-{5-C5H 4(CH2)2PPh2}]PF6(5), which is isolated as a mixture of stereoisomers. Complex 4 also reacts with phenylacetylene in the presence of TlPF6. The reaction leads to the hydride-alkynyl-osmium(IV) derivative [OsH{η5-C5H 4(CH2)2PPh2}(C≡CPh)(P iPr3)]PF6 (6), which is not stable and evolves into the vinylidene [OsH{η5-C5H4(CH 2)2PPh2}(=C=CHPh)(PiPr 3)]PF6 (7). Deprotonation of 7 with methanol solutions of KOH yields the neutral alkynyl compound [OsH{η5-C 5H4(CH2)2PPh2} (C≡CPh)(PiPr3)] (8). The addition of HPF 6·H2O to 8 regenerates 7. Similarly to phenylacetylene, 1,1-diphenyl-2-propyn-l-ol reacts with 4 and TIPF6 to give the hydride-hydroxyalkynyl derivative [OsH{η5-C 5H4(CH2)2PPh2} {C≡CC)(OH)Ph2iPr3)]-PF6 PF6 (9), which dehydrates to produce the allenylidene [OsH{η5-C5H4(CH2) 2PPh2}(=C=C=CPh2)(PiPr 3)]PF6 (10). Addition of HPF6·H 2O to 10 affords the dicationic alkenyl carbyne [Os{η5-C5H4(CH2) 2PPh2}(≡CCH=CPh2)(PiPr 3)](PF6)2 (11). Complexes 2 and 4 have been characterized by X-ray diffraction analysis.
