This invention relates to a
transition metal compound represented by the formula: wherein M is a group 3, 4, 5 or 6
transition metal atom, or a
lanthanide metal atom, or
actinide metal atom; E is: 1) a substituted or unsubstituted indenyl ligand that is bonded to Y through the four, five, six or seven position of the indenyl ring, or 2) a substituted or unsubstituted heteroindenyl ligand that is bonded to Y through the four, five or six position of the heteroindenyl ring, provided that the bonding position is not the same as the position of the ring
heteroatom, or 3) a substituted or unsubstituted fluorenyl ligand that is bonded to Y through the one, two, three, four, five, six, seven or eight position of the fluorenyl ring, or 4) a substituted or unsubstituted heterofluorenyl ligand that is bonded to Y through the one, two, three, four, five or six position of the heteroindenyl ring, provided that the bonding position is not the same as the position of the ring
heteroatom; A is a substituted or unsubstituted cyclopentadienyl ligand, a substituted or unsubstituted heterocyclopentadienyl ligand, a substituted or unsubstituted indenyl ligand, a substituted or unsubstituted heteroindenyl ligand, a substituted or unsubstituted fluorenyl ligand, a substituted or unsubstituted heterofluorenyl ligand, or other mono-anionic ligand; Y is a Group 15 or 16 bridging
heteroatom substituent that is bonded via the heteroatom to E and A; and X are, independently, univalent anionic ligands, or both X are joined and bound to the
metal atom to form a metallocycle ring, or both X join to form a chelating ligand, a
diene ligand, or an alkylidene ligand. This invention further relates to catalyst systems comprising the above transiotioon metal compounds, activators and optional supports and their use to polymerize or oligomerize olefins.