Constrained geometry catalysts for the production of polymers


Project ID: D2009-89


Polymerization reactions are used in industry to make widely used products, such as polyolefins. There has been an interest in improving control over polymer tacticity and co-polymerization, leading to the development of Constrained Geometry Catalysts (CGCs). The CGCs form complexes with a pi-bonded moiety bridged to a donor group on a shared metal center. The angle formed results in a constrained geometry and an active catalyst for polymerization. CGCs are typically dianionic and made with group 3 and 4 metals, with a strong focus on titanium and zirconium. Although these metals have been found to be active, complexes incorporating group 5 and 6 metals with trianionic ligands are desirable for greater control over polymer properties.


Invention Description

Researchers from the University of Toledo have created a catalyst system for producing CGCs that can incorporate group 4-6 metals. Trianionic ligand precursors are utilized to make homogenous and heterogeneous CGCs that act as single-site molecular compounds. The technology results in the formation of a six-membered chelate ring and a unique coordination environment in comparison to other CGCs.



•       Polyolefins, polyethers, fine chemicals, and pharmaceutical intermediates

•       Metathesis reactions

•       Hydroamination of alkenes

•       Oligomerization

•       Polymerization of alkenes, epoxides, cyclic ethers, lactones, and other monomers



•       Precise control over polymer properties, such as tacticity and molecular weight

•       Tunable to achieve desired activity and selectivity of catalyst

•       Compatible with group 4-6 metals


IP Status:       Issued U.S. Utility Patent 8,524,846


Publication:  R. T. Rondo 2010. Development of Constrained Geometry Complexes of Group 4 and 5 Metals.


Patent Information:
For Information, Contact:
Stephen Snider
AVP Tech Transfer
The University of Toledo
419 530 6225
Mark Mason
Geometry constrained