tert-Butylsilylcyclopentadienyl Group 4 metal complexes

Wolfgramm, R.; Ramos, Cristina; Royo, Pascual; Lanfranchi, Maurizio; Pellinghelli, Maria Angela; Tiripicchio, António

doi:10.1016/s0020-1693(02)01446-9

“…The 1 H NMR spectrum of 2 shows two singlets for the Zr-methyl groups, one shifted significantly highfield (δ ϭ Ϫ1.29) compared with the typical value (δ ϭ 0.09 ppm) observed for the other, which was in the range found for related methyl zirconocenes. [30] NOE experiments demonstrated that the highfield singlet is due to the methyl group located under the benzene ring attached to the indenyl moiety. Similar behavior was observed for the four doublets due to the two diastereotopic methylene protons of the benzyl (3) and methylsilyl (4) ligands.…”

Section: Methodsmentioning

confidence: 99%

Diastereoselective Insertion of Isocyanide into the Alkyl−Metal Bond of Methylbenz[e]indenyl ansa‐Zirconocene Complexes

Sebastián

¹

,

Royo

²

,

Gómez‐Sal

³

et al. 2004

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Alkylation of ansa‐zirconocene [Zr{(η5‐C5H5)SiMe2(MBI)}Cl2] (MBI = η5‐2‐Me−C13H7) with MgRCl gave the dimethyl complex [Zr{(η5‐C5H5)SiMe2(MBI)}Me2], but unresolvable mixtures containing mono‐alkylated compounds were obtained when bulkier alkyls were used. However pure dialkyl complexes [Zr{(η5‐C5H5)SiMe2(MBI)}R2] (R = CH2Ph, CH2SiMe3) were easily obtained using K(CH2Ph) and Li(CH2SiMe3) as alkylating agents. Diastereoselective insertion into the MBI‐unprotected Zr−R bond was observed when all of these dialkyl complexes were treated with 2,6‐xylyl isocyanide to give the iminoacyl compounds [Zr{(η5‐C5H5)SiMe2(MBI)}R{CR[η2‐N‐(2,6‐xylyl)]}] (R = Me, CH2Ph, CH2SiMe3). All of the new complexes were characterized by NMR spectroscopy and the X‐ray molecular structures of the dibenzyl and the imino‐benzyl compounds were determined. The catalytic activity for ethene polymerization and ethene/1‐hexene copolymerization of the dichloro zirconocenes [Zr{(η5‐C5H5)EMe2(MBI)}Cl2] (E = C, Si), activated with methylalumoxane (MAO), was measured. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)

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Thallium: Organometallic ChemistryBased in part on the article Thallium: Organometallic Chemistry by William S. Rees, Jr. & Gertrud Kräuter which appeared in theEncyclopedia of Inorganic Chemistry, First Edition.

Pike¹

2005

Encyclopedia of Inorganic Chemistry

0

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The organometallic chemistry of thallium(I) is dominated by cyclopentadienyl complexes. These may be polymeric through bridging Cp arrangements or oligomeric as a result of Tl⋯Tl contacts. ThCp complexes are easily prepared and are highly useful Cp‐transfer agents. There are two known Tl(I) organometallics with direct TlC σ‐bonds; one is monomeric and the other is tetrameric due to Tl⋯Tl contact. A variety of Tl(I) π‐complexes are recognized. Bonding in the latter tends to be fairly weak. Two R 2 TlTlR 2 dimers (R = silyl group) are known, but no such Tl(II) complexes are known for carbon ligands. The chemistry of organothallium(III) compounds is more extensive, encompassing such species as R 3 Tl, R 2 TlX, RTlX 2 (X = anionic ligand), and complexes of these species with additional ligands. A wide array of X‐ray crystal structures for Tl(III) complexes reveals monomeric, oligomeric, and polymeric arrangements, with bridging ligands being very common. Thallium compounds are highly toxic and should be handled with great care. Volatile Tl species are of use in the chemical‐vapor deposition of superconducting phases. Finally, Tl(III) salts are fairly important reagents in organic syntheses, especially in oxidations and in ring expansion and contraction reactions.

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Thallium: Organometallic ChemistryBased in part on the article Thallium: Organometallic Chemistry by William S. Rees, Jr. & Gertrud Kräuter which appeared in theEncyclopedia of Inorganic Chemistry, First Edition.

Pike

¹

2005

Encyclopedia of Inorganic and Bioinorganic Chemistry

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The organometallic chemistry of thallium(I) is dominated by cyclopentadienyl complexes. These may be polymeric through bridging Cp arrangements or oligomeric as a result of Tl⋯Tl contacts. ThCp complexes are easily prepared and are highly useful Cp‐transfer agents. There are two known Tl(I) organometallics with direct TlC σ‐bonds; one is monomeric and the other is tetrameric due to Tl⋯Tl contact. A variety of Tl(I) π‐complexes are recognized. Bonding in the latter tends to be fairly weak. Two R 2 TlTlR 2 dimers (R = silyl group) are known, but no such Tl(II) complexes are known for carbon ligands. The chemistry of organothallium(III) compounds is more extensive, encompassing such species as R 3 Tl, R 2 TlX, RTlX 2 (X = anionic ligand), and complexes of these species with additional ligands. A wide array of X‐ray crystal structures for Tl(III) complexes reveals monomeric, oligomeric, and polymeric arrangements, with bridging ligands being very common. Thallium compounds are highly toxic and should be handled with great care. Volatile Tl species are of use in the chemical‐vapor deposition of superconducting phases. Finally, Tl(III) salts are fairly important reagents in organic syntheses, especially in oxidations and in ring expansion and contraction reactions.

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tert-Butylsilylcyclopentadienyl Group 4 metal complexes

Cited by 8 publications

References 25 publications

Diastereoselective Insertion of Isocyanide into the Alkyl−Metal Bond of Methylbenz[e]indenyl ansa‐Zirconocene Complexes

Diastereoselective Insertion of Isocyanide into the Alkyl−Metal Bond of Methylbenz[e]indenyl ansa‐Zirconocene Complexes

Thallium: Organometallic ChemistryBased in part on the article Thallium: Organometallic Chemistry by William S. Rees, Jr. & Gertrud Kräuter which appeared in theEncyclopedia of Inorganic Chemistry, First Edition.

Thallium: Organometallic ChemistryBased in part on the article Thallium: Organometallic Chemistry by William S. Rees, Jr. & Gertrud Kräuter which appeared in theEncyclopedia of Inorganic Chemistry, First Edition.

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