Activation of Metallocene Precatalysts

The metallocene species after activation is a d , cationic, 14-electron species with a pseudotet-rahedral structure and a highly Lewis acidic metal center. Two of the four coordination sites on the metal are occupied by the ligands, such as ri -cyclopentadienyl (Cp, C5H5) groups or other moieties. The two remaining sites participate directly in the polymerization process. 

SCHEME 1.1 Formation of an active catalyst species from a metallocene dichloride. 

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