This award in the Division of Chemistry supports research by Professor Geoffrey Coates at Cornell University to develop new bimetallic complexes that have potential utility as catalysts for the synthesis of polymeric materials. The work will focus on the utilization of epoxides in polymer synthesis for three primary reasons: 1) epoxides are inexpensive chemical feedstocks; 2) epoxides can be derived from biorenewable sources; and 3) epoxides can be used to make polyethers, polyesters, and polycarbonates, all of which safely biodegrade in the environment. Work will focus on the development of a range of bimetallic zinc and cobalt complexes for epoxide polymerization. Specific objectives are: 1) the development of chiral catalysts that can control the stereochemistry of the polymerization, resulting in semi-crystalline polymers with improved properties over their stereorandom counterparts; 2) understanding the design challenges of bimetallic catalysts, from both an organic and inorganic perspective, and utilization of these new catalysts for polymer synthesis. The target polymers are polyethers from epoxide homopolymerization, polycarbonates from epoxide/CO2 copolymerization, and polyesters from epoxide/anhydride copolymerization.
The proposed work centers on developing bimetallic catalysts for environmentally benign epoxide transformations including polycarbonates from epoxide/CO2 copolymerization. Outreach activities include a variety of chemistry demonstrations and hands-on, inquiry based experiments in local elementary and middle schools. During the last funding period, the PI and his group have spent over 140 hours in K-12 outreach activities, interacting with 780 students and 201 teachers. The research on synthesizing plastics from natural substances is easily accessible by the general public and this research group endeavors to actively engage with television networks, newspapers and magazines to help the general public see that science has great potential to meet the needs of society in an environmentally responsible way.
The objective of this grant was to develop new bimetallic complexes that have potential utility as catalysts for the synthesis of improved polymeric materials. Many of nature’s catalysts (enzymes) have two or more metals that work together to carry out important reactions. Using biomimicry, we have developed related bimetallic catalysts that can be used to make plastics. The work focused on the utilization of abundant, commercial monomers called "epoxides" in polymer synthesis for three primary reasons: 1) epoxides are inexpensive chemical feedstocks; 2) epoxides can be derived from biorenewable sources; and 3) epoxides can be used to make polyethers, polyesters, and polycarbonates, all of which safely biodegrade in the environment. Of particular intellectual merit is our study of bimetallic catalysts that can make ordered arrays of epoxide monomers. Common foam cushions are made from epoxide polymers where the polymer chains lack order of substituents along the backbone. Our new catalyst controls the arrangement of the substituents, resulting in a hard material (versus the current soft material). The broader impacts of these results is that hard foams can now be made from the inexpensive feedstocks that are currently used to make soft foams. These hard materials have many potential applications, including solid foam insulation, plastic can liners, architectural coatings, and hot melt adhesives that rapidly set upon cooling.
