1271740-51-2Relevant articles and documents
Preparation of half-sandwich alkoxycarbene complexes of osmium(II)
Albertin, Gabriele,Antoniutti, Stefano,Castro, Jesus
, p. 1558 - 1568 (2011/04/24)
Alkoxy-alkylcarbene complexes [OsCl{=C(OR′)CH 2R′′}(η6-p-cymene)L]BPh4 (1-4) [R′ = Me, Et; R′′ = Ph, p-tolyl, But; L = P(OMe)3, P(OEt)3, PPh(OEt)2, PPh 2OEt] were prepared by allowing dichloro compounds OsCl 2(η6-p-cymene)L to react with terminal alkyne R′′C=CH in alcohol. Ethoxy-methylcarbene [OsCl{=C(OEt)CH 3}(η6-p-cymene)L]BPh4 (5) was also prepared from reaction with trimethylsilyl acetylene. A reaction path for the formation of compounds 1-5, involving the nucleophilic attack of alcohol on intermediate vinylidene complexes, is discussed. Acetylide derivatives OsCl(C=CAr) (η6-p-cymene)L (6, 7) [Ar = Ph, p-tolyl; L = P(OMe)3, P(OEt)3, PPh(OEt)2] were prepared by reacting dichloro compounds OsCl2(η6-p-cymene)L with lithium acetylide (Li+[ArC=C]-) in thf. Protonation reaction with Bronsted acids of 6 and 7 led to vinylidene cations [OsCl{=C=C(H)Ar} (η6-p-cymene)L]+. Complexes OsCl2(η 6-p-cymene)L also reacted with both PhC=CH and (CH3) 3SiC=CH in the presence of H2O to give alkyl-carbonyl derivatives [Os(η1-CH2Ph)(CO)(η6-p- cymene)L]BPh4 (8) and [Os(η1-CH3)(CO) (η6-p-cymene)L]BPh4 (9). The complexes were characterized spectroscopically (IR and 1H, 13C, 31P NMR) and by X-ray crystal structure determinations of [OsCl{=C(OEt)CH2Ph}(η6-p-cymene){PPh(OEt) 2}]BPh4 (1c), [OsCl{=C(OEt)CH2Ph} (η6-p-cymene)(PPh2OEt)]BPh4 (1d), and [Os(η1-CH2Ph)(CO)(η6-p-cymene){PPh(OEt) 2}]BPh4 (8c).
