Patent ID: 7557171

Claim:
A metallocene compound represented by the formula (1): wherein M is a Group 4, 5 or 6 transition metal atom; E is a substituted or unsubstituted polycyclic arene ligand pi-bonded to M; A is a substituted or unsubstituted monocyclic or polycyclic arene ligand pi-bonded to M; at least one of A and E has at least one halogen substituent directly bonded to any sp 2 carbon atom at a bondable ring position of the associated ligand; Y is bonded to any single bondable ring position of A and to any single bondable ring position of an aromatic six-membered ring of E, and is a bridging group containing a Group 13, 14, 15, or 16 element; and each X is a univalent anionic ligand, or two X are joined and bound to the metal atom to form a metallocycle ring, or two X are joined to form a chelating ligand, a diene ligand, or an alkylidene ligand.