Darstellung und Eigenschaften von Chromorganylen aus Phillips‐Katalysatoren und Ethylen

Surface Compounds of Transition Metals. XLI 1] Preparation and Properties of Organochromium Compounds by Reaction of Phillips Catalysts with Ethylene Reaction of reduced Phillips catalysts with ethylene at 300 °C deactivates the catalyst; supported organochromium compounds are formed. These can be cleaved from the silica support by HCl and other acids, and transferred into solution by extraction with CH₃OH. Chromatography yields fractions of organochromium compounds which differ by CH₂ moieties. XPS, ^1/2H NMR, and mass spectra as well as magnetic measurements prove that an ensemble of (R_nCp)CrCl₂(CH₃OH) (R_nCp = alkylated cyclopentadienyl) has been formed. The R_nCp ligand results from a chromium‐assisted oxidative coupling of the olefin with or without CC‐cleavage. According to UV/Vis and mass spectroscopy Cl^– and CH₃OH can be substituted for other anions and donor molecules. Without a donor dinuclear, Cl‐bridged molecules are obtained, of which (1,2,3‐Me₃Cp)CrCl₂]₂ was established by crystal structure analysis. Reaction with O₂ reversibly leads to chromium(V) compounds of the type (R₂Cp)Cr(O)Cl₂.