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Inversion of stereoselectivity in a metallocene catalyst

✍ Scribed by Tetsunosuke Shiomura; Tadashi Asanuma; Norihide Inoue

Publisher
John Wiley and Sons
Year
1996
Tongue
English
Weight
253 KB
Volume
17
Category
Article
ISSN
1022-1336

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✦ Synopsis

Abstract

Inversion of stereoselectivity of a particular metallocene (Me~2~Si(Flu) (N‐t‐Bu)ZrCl~2~) (Me: methyl, Flu: fluorenyl, t‐Bu: tert‐butyl) from syndiospecific into isospecific was observed by changing the cocatalyst from methylaluminoxane (MAO) to [Ph~3~C]^+^ [B(C~6~F~5~)~4~]^βˆ’^/AliBu~3~ (iBu:isobutyl). The change of the solvent‐separated ion pair (in case of MAO as cocatalyst) into the contact ion pair (in case of the more polar and less bulky borate anion) was proposed as the plausible explanation of this phenomenon.

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