American Chemical Society
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Structural Characterization of an (s-trans4-Butadiene) Group 4 ansa-Metallocene Complex

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journal contribution
posted on 1999-09-17, 00:00 authored by Marc Dahlmann, Gerhard Erker, Roland Fröhlich, Oliver Meyer
Treatment of the ansa-metallocene dichloride rac-Me2Si(C5H3CH3)ZrCl2 (1) with “butadiene-magnesium” gave a 82:8:10 mixture of the respective (s-trans4-butadiene)metallocenes 2a and 2b and the (s-cis-butadiene)Me2Si(C5H3CH3)2Zr isomer, 2c. One of the (s-trans-diene)metallocene isomers was characterized by X-ray diffraction. The typical bonding parameters of the (s-trans4-butadiene)Zr unit are Zr−C1 2.453(3), Zr−C2 2.352(3), Zr−C3 2.338(2), and Zr−C4 2.455(3) Å. The butadiene C−C bond lengths are within a narrow range between 1.402(5) (C1−C2), 1.393(5) (C2−C3), and 1.364(6) Å (C3−C4). The C1−C2−C3−C4 torsional angle amounts to 124.3(4)°. These values are to be regarded as typical for (s-trans4-butadiene) group 4 metallocene complexes.