| abstract |
The catalyst composition and the polymerization system comprise at least one thiourea complex according to formula (I) Wherein M is Ti, Zr, or Hf; a is 1 or 2; Each Q group of the thiourea complex is a divalent thiourea ligand attached to the metal center and has the formula (Ia), (Ib), or (Ic) In the formulas (Ia), (Ib) and (Ic), each group R 1 , R 2 , and R 3 is independently selected from an alkyl group or an aryl group; Each group Z < 1 > or Z < 2 > is independently selected from alkylene groups. When a = 2, the groups R 1 of two groups Q are optionally connected, or the groups R 3 of two groups Q are optionally connected. Each X is covalently bonded or coordinated to the metal center and is independently selected from alkyl groups or halides. The polymerization system may be configured to copolymerize ethylene and alpha-olefins. |