Osmium Alkyl and Silyl Derivatives with Cyclopentadienyl(phosphine) and Pentamethylcyclopentadienyl(phosphine) Ligand Sets
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- 作者：Paulus W. Wanandi and T. Don Tilley
- 刊名：Organometallics
- 出版年：1997
- 出版时间：September 30, 1997
- 年：1997
- 卷：16
- 期：20
- 页码：4299 - 4313
- 全文大小：611K
- 年卷期：v.16,no.20(September 30, 1997)
- ISSN：1520-6041
文摘
The preparation and characterization of newosmium(II) and osmium(IV) silyl derivativescontaining the cyclopentadienyl(phosphine) andpentamethylcyclopentadienyl(phosphine)ligand sets are described. The osmium silyl complexes are preparedby thermal reactionsof hydrosilanes with osmium(II) alkyl complexes of the typeCp'(PR3)2OsCH2SiMe3(Cp' =Cp, R = Ph (4), Me (5); Cp' =
BORDER=0 >5-C5Me5, R = Me(7)), which in turn are available viaalkylationof the corresponding bromo complexes. The synthesis of alkylderivatives of Cp(PR3)2Os(R= Ph, Me) requires the use of dialkylmagnesium reagents, whilealkylation of the moreelectron-rich Cp*(PMe3)2Os system canbe achieved using Grignard reagents. Additionally,reaction of Cp(PPh3)2OsBr with AgOTf(Tf = SO2CF3) affords the osmium(II)triflate complexCp(PPh3)2OsOTf (2), whichpossesses a labile triflate group. The structure of complex2was determined by X-ray crystallography. Similar to theirruthenium analogs, the osmium(II) alkyl complexes 4, 5, and 7thermally activate arene C-H bonds. Reaction of 7withHSiR2[S(p-Tol)] (R =S(p-Tol), Me) provides metallacycle complexes of the typeCp*(PMe3)(H)Os[C6H3(3-Me)(6-S) SiR2](R = S(p-Tol) (11), Me (13)) viaactivation of both the Si-Hand arene C-H bonds in the silanes. The X-ray structure of13 is described. Alkyl complexes4, 5, and 7 react withHSiR2Cl (R = Ph, Me) to give osmium(II) silyland/or osmium(IV)bis(silyl) hydride species, depending on the reaction conditionsand the strength of the Os-Pbond. Reaction of 7 with HSiMeCl2 orHSiCl3 affords, exclusively, the osmium(II)silylderivatives. Exchange reactions at silicon are used to synthesizeCp*(PMe3)2OsSiMe2OTf(24) andCp*(PMe3)2OsSiMe[S(p-Tol)]2(25) from the corresponding chloro(silyl)complexesCp*(PMe3)2OsSiMe2Cl(17) andCp*(PMe3)2OsSiMeCl2(18). The solution behavior and solid-state structure of 24 indicate that the compound may bedescribed as a base-stabilized silylenecomplex.
BORDER=0 >5-C5Me5, R = Me(7)), which in turn are available viaalkylationof the corresponding bromo complexes. The synthesis of alkylderivatives of Cp(PR3)2Os(R= Ph, Me) requires the use of dialkylmagnesium reagents, whilealkylation of the moreelectron-rich Cp*(PMe3)2Os system canbe achieved using Grignard reagents. Additionally,reaction of Cp(PPh3)2OsBr with AgOTf(Tf = SO2CF3) affords the osmium(II)triflate complexCp(PPh3)2OsOTf (2), whichpossesses a labile triflate group. The structure of complex2was determined by X-ray crystallography. Similar to theirruthenium analogs, the osmium(II) alkyl complexes 4, 5, and 7thermally activate arene C-H bonds. Reaction of 7withHSiR2[S(p-Tol)] (R =S(p-Tol), Me) provides metallacycle complexes of the