title: Unexpected Reactions between Ziegler-Natta Catalyst Components and Structural Characterization of Resulting Intermediates.
abstract: In this work, we investigated precursors and procatalysts with well-defined crystal structures and morphologies in Ziegler-Natta systems to improve our understanding of the nature of the active metal sites. Molecular cluster precursors such as [Mg4Ti3(μ6-O)(μ3-OH)3(μ-OEt)9(OEt)3(EtOH)3Cl3], [Mg4Ti3(μ6-O)(μ3-OH)(μ3-OEt)2(μ-OEt)9(OEt)3(EtOH)3Cl3], and [Mg6Ti4(μ6-O)2(μ3-OH)4(μ-OEt)14(OEt)4(EtOH)2Cl2] were prepared via simple elimination of the cyclopentadienyl ring from Cp2TiCl2 as CpH in the presence of magnesium metal and ethanol. Titanocene dichloride acts as both a source of titanium and a magnesium-chlorinating agent. The resulting novel complexes were characterized using single-crystal X-ray diffraction. In these compounds, Ti(OEt)4 molecules are grafted onto Mg4 and Mg6 ethoxide cubane-like surfaces; this strongly affects the procatalyst morphology, which is transferred to the polymer. Mg4(OR)8 units act as carriers for the AlR3 co-catalyst, resulting in return of alkyl functions to the Ti center.
authors.affiliation: Faculty of Chemistry, University of Wrocław , 14 F. Joliot-Curie, 50-383 Wrocław, Poland.
authors.forename: Piotr
authors.initials: P
authors.lastname: Sobota
authors.affiliation: Faculty of Chemistry, University of Wrocław , 14 F. Joliot-Curie, 50-383 Wrocław, Poland.
authors.forename: Józef
authors.initials: J
authors.lastname: Utko
authors.affiliation: Faculty of Chemistry, University of Wrocław , 14 F. Joliot-Curie, 50-383 Wrocław, Poland.
authors.forename: Tadeusz
authors.initials: T
authors.lastname: Lis
authors.affiliation: Faculty of Chemistry, University of Wrocław , 14 F. Joliot-Curie, 50-383 Wrocław, Poland.
authors.forename: Łukasz
authors.initials: Ł
authors.lastname: John
authors.affiliation: Faculty of Chemistry, University of Wrocław , 14 F. Joliot-Curie, 50-383 Wrocław, Poland.
authors.forename: Rafał
authors.initials: R
authors.lastname: Petrus
authors.affiliation: Faculty of Chemistry, University of Wrocław , 14 F. Joliot-Curie, 50-383 Wrocław, Poland.
authors.forename: Anna
authors.initials: A
authors.lastname: Drąg-Jarząbek