| abstract |
Single-site catalysts useful for polymerizing olefins are disclosed. The organometallic catalysts incorporate a Group 3 to 10 transition, lanthanide or actinide metal and a caged diimide ligand. The diimide ligands are made by a tandem Diels-Alder and photochemical [2+2] cycloaddition sequence to give a multicyclic dione, followed by condensation with a primary amine. Because a wide variety of caged diimide ligands are easy to prepare from commercially available dienes and dienophiles, the invention enables the preparation of a new family of single-site catalysts. Based on their unique structure and geometry, the catalysts offer polyolefin producers new ways to improve activity, control comonomer incorporation, or regulate polyolefin tacticity. |