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Journal article

Rac/ m eso Transformations of Disiloxane-bis(1-indenyl)-a nsa-ferrocenes: An X-ray Crystallographic and NMR Study

Abstract

Both stereoisomers of disiloxane-bis(1-indenyl)-ansa-ferrocene, Fe(η5-inden-1-yl-SiMe2)2O, 1, were prepared by the reaction of disiloxane-bis-1,3-inden-1‘-yl anion with FeCl2; the diastereomers were separated by column chromatography and recrystallized from n-heptane. A single-crystal X-ray diffraction study confirmed that each stereoisomer, racemic 1 r and meso 1 m , involves parallel bis-indenyl coordination to the Fe metal center. These isomers were also characterized by 1H, 13C, and 29Si NMR and IR spectroscopy. Compounds 1 r and 1 m could each be transformed into the other diastereomer: the conversion was retarded by base, but accelerated under weakly acidic conditions. The mechanism of this process, investigated using deuterium labeling experiments, is consistent with a series of successive 1,5-suprafacial, sigmatropic silicon shifts. Compound 1 was also copolymerized with 1,1,3,3,5,5,7,7-octamethylcyclotetrasiloxane (D4) and 1,1,1,3,3,5,5,5-octamethyltrisiloxane (MDM) to produce green organometallic polymers.

Authors

Amako M; Schinkel J; Brook MA; McGlinchey MJ; Britten JF

Journal

Organometallics, Vol. 24, No. 7, pp. 1533–1543

Publisher

American Chemical Society (ACS)

Publication Date

March 1, 2005

DOI

10.1021/om0491847

ISSN

0276-7333

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