ansa - Metallocene derivatives XXIII * .
نویسندگان
چکیده
9 Titanocene and zirconocene complexes with a phenyl or I-naphthyl substituent in one ,B-position of each Cs-ring ligand and with an interannular tetramethylethanoor dimethylsilano-bridge have been prepared. Racemic complex isomers, which are formed together with varying amounts of their meso isomers, were separated from the latter and characterised by lH NMR spectroscopy and X-ray crystallographic studies.
منابع مشابه
ansa-Metallocene derivatives XXI *. Syntheses of etheno-bridged ansa-titanocene derivatives by the McMurry reaction
207 Novel olefin-linked biscylopentadienylligands have been prepared by McMurry coupling reactions of benzoyland acetyl-cyclopentadienyl sodium. Reactions of the disodium salts with TiC1 4 or TiCl 3 • 3THF afford the alkene-bridged ansa-titanocene dichlorides. 13C-NMR shifts of the bridge carbon atoms do not indicate any interaction between the olefin 'IT-system and the metal.
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Alkali metal complexes of two types of ansa-tris(allyl) ligand are reported; a monoanionic ansa-tris(allyl) ligand containing tin(II) is formally valence isoelectronic to the cyclopentadienyl ligand and a trianionic ansa-tris(allyl) ligand containing silicon(IV) is formally valence isoelectronic to an ansa-metallocene ligand; the potential wider use of these tripodal ligands in coordination che...
متن کاملAnsa-metallocene polymerization catalysts derived from [2+2]cycloaddition reactions of bis(1-methylethenyl-cyclopentadienyl)zirconium systems.
Bis(1-methylethenyl-cyclopentadienyl)zirconium dichloride (7a) was prepared by a fulvene route. Photolysis at 0 degrees C with Pyrex-filtered UV light resulted in a rapid and complete intramolecular [2+2]cycloaddition reaction to yield the corresponding cyclobutylene-bridged ansa-zirconocene dichloride isomer (8a). This is one of the rare examples of an organic functional group chemistry that l...
متن کاملBryce Sunsdahl
Metallocene and ansa-metallocene complexes of group 3 metals and the Lanthanides have shown to be effective catalysts for a number of chemical reactions. These include alkene polymerization, hydrosilation, hydroboration, hydrogenation and hydroamination. The coordinatively unsaturated, monomeric permethylyttrocene complexes in particular have proven to be highly effective for carrying out these...
متن کاملSilicon-Carbon bond cleavage reactions of Ansa tungstenocene compounds: the [Me2Si] bridge as a site for metallocene functionalization.
[Me(2)Si(Cp(Me(2)))(2)]W(H)Cl is obtained via reaction of WCl(6) with a mixture of [Me(2)Si(Cp(Me(2)))(2)]Li(2) and NaBH(4), from which the dichloride [Me(2)Si(Cp(Me(2)))(2)]WCl(2) is obtained via treatment with CHCl(3). [Me(2)Si(Cp(Me(2)))(2)]WCl(2) provides a means to access other ansa tungstenocene compounds, such as [Me(2)Si(Cp(Me(2)))(2)]WH(2), [Me(2)Si(Cp(Me(2)))(2)]WMe(2), and [Me(2)Si(C...
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