Constrained geometry complex

In organometallic chemistry, a "constrained geometry complex" (CGC) is a kind of catalyst used for the production of polyolefins such as polyethylene and polypropylene.

CGC complexes feature a pi-bonded moiety (e.g. cyclopentadienyl) linked to one of the other ligands on the same metal centre in such a way that the angle at this metal between the centroid of the pi-system and the additional ligand is smaller than in comparable unbridged complexes.

[2] More specifically, the term CGC was used for ansa-bridged cyclopentadienyl amido complexes, although the definition goes far beyond this class of compounds.

CGC derived polymers are currently marketed by The Dow Chemical Company as part of their INSITE technology.

[5] The following year patents were issued to The Dow Chemical Company and Exxon for applications in alkene polymerization.