Zirconium hydrocarbyl chemisorption on sulfated metal oxides: New supports, chemisorption pathways, and implications for catalysis

The sulfated metal oxides (SMOs) sulfated stannia (SnS), sulfated iron oxide (FeS), and sulfated titanium dioxide (TiS) have been synthesized and examined as support materials/cocatalysts/activators for molecule-based olefin polymerization and hydrogenation catalysis. C-13 CPMAS NMR spectroscopic analysis Of Cp2Zr((CH3)-C-13)(2)/SMO chemisorption shows that cationic zirconocenium species are formed along with varying amounts of catalytically inactive mu-oxo (Cp2Zr(CH3)O-surface) species, depending on the support material. Ethylene polymerization data with the supported catalysts show that polymerization activity is dependent on both precursor ligation [Zr(CH2Ph)(4) > (Me5Cp)ZrMe3] and the nature of the support (SnS > FeS > TiS). Poisoning studies were performed in conjunction with ethylene polymerization, mediated by (Me5CP)ZrMe3 supported on each SMO, and reveal that, for (Me5Cp)ZrMe3/SnS, 61 +/- 5% of the Zr sites are catalytically significant, while, for (Me5CP)ZrMe3/FeS, this quantity is 22 +/- 2%, and for (Me5Cp)ZrMe3/TiS, 63 +/- 9%. These catalysts are also active for benzene hydrogenation and are separable from liquid-phase products using physical or, in the case of FeS, magnetic techniques.