Acetyl-hydroxy-fulvene: A new ligand for chromium-catalyzed polymerization of ethylene at room temperature. Crystal structures of the ligands and chromium complex
Abstract
In the field of transition metal catalysts for olefin polymerization, the discovery of new chelating ligands has attracted significant interest. This paper reports on the polymerization of ethylene with new chromium based catalysts containing an acetyl-hydroxy-fulvene ligand. A parallel method was applied to screen eleven metal salts versus two different functionalized fulvene ligands. A direct visual analysis showed solid PE formation only in vials containing a chromium salt after 1 h of polymerization at 35 °C and 15 bar. This preliminary screening was followed by optimization studies to obtain high activities (up to 5 tPE/(mol·h)). ORTEP structures of the corresponding ligands and of the best catalysts were reported