A catalyst system useful for polymerizing olefins is disclosed The catalyst system comprises an activator and a bimetallic complex that incorporates two Group 3 to 10 transition metal atoms, which may be the same or different, and a neutral or anionic indigoid ligand By proper selection of the indigoid skeleton and by modifying its substituents and transition metal centers, polyolefin makers can fine-tune the bimetallic complexes to control activity, enhance comonomer incorporation, and optimize polymer properties

Gadient Engi

Papers

Tribromo derivatives of indigo and process of making same.