Surface compounds of transition metals. XLI - Preparation and properties of organochromium compounds by reaction of Phillips catalysts with ethylene

Reaction of reduced Phillips catalysts with ethylene at 300 degrees C deact ivates the catalyst; supported organochromium compounds are formed. These c an be cleaved from the silica support by HCl and other acids, and transferr ed into solution by extraction with CH3OH. Chromatography yields fractions of organochromium compounds which differ by CH2 moieties. XPS, H-1/2 NMR, a nd mass spectra as well as magnetic measurements prove that an ensemble of (RnCp)CrCl2(CH3OH) (RnCp = alkylated cyclopentadienyl) has been formed. The RnCp ligand results from a chromium-assisted oxidative coupling of the ole fin with or without CC-cleavage. According to UV/Vis and mass spectroscopy Cl- and CH3OH can be substituted for other anions and donor molecules. With out a donor dinuclear, Cl-bridged molecules are obtained, of which [(1,2,3- Me3Cp)CrCl2](2) was established by crystal structure analysis. Reaction wit h O-2 reversibly leads to chromium(V) compounds of the type (R2Cp)Cr(O)Cl-2 .