Broadening Access to Cyclic Polymers through Better Catalyst Design and Synthesis

University Of Florida, Gainesville FL

Investigators

Abstract

With the support of the Chemical Catalysis program in the Division of Chemistry, Professor Adam S. Veige of University of Florida is developing new catalysts for the synthesis of cyclic polymers. Catalysts can be designed to perform many functions. In the case of polymer synthesis, the metal ion gathers the monomeric building blocks and stitches them together to create large oligomeric molecules (polymers). Synthetic polymers are used in almost every aspect of our lives and are present in the materials we use daily. The polymers are almost exclusively long molecular chains containing chain ends. The properties of polymers are dictated by both the monomeric repeating unit (i.e. the chain links) and by the chain ends. Cyclic polymers do not have chain ends. Many advantageous properties can result from the lack of chain ends. For example, these cyclic polymers generally have improved optical properties, higher melting temperature, lower friction, reduced viscosity, and smaller size. The challenge is to build polymers without chain ends. This project involves the synthesis and design of several new tungsten- and molybdenum-based catalysts that can stitch together monomers to create cyclic polymers on a large scale. Another aspect of the research focuses broadening access to these highly specialized catalysts so other researchers can expand the scope of cyclic polymer and catalyst research rapidly. The research activities associated with this award are expected to increase broadening participation and enable training of high school, undergraduate, and graduate students in catalysis chemistry. The longstanding public outreach event “Halloween Molecular Mania”, hosted by the Dr. Veige and the Center for Catalysis at the University of Florida, involves presenting science in an interactive forum to the local community. The current project aims to create new methods of communicating scientific concepts though this outreach mechanism to participating local teachers, high school students, and their parents. Under this award from the Chemical Catalysis program in the Division of Chemistry, Professor Adam S. Veige of University of Florida is developing new catalysts for the synthesis of cyclic polymers. In the first goal, a unique alkylidyne will be synthesized that has the capacity to polymerize alkynes to give new cyclic polymer materials. New ligand designs and new metalation strategies will be explored that have the potential to broaden catalyst design principles in organometallic chemistry. A second goal focuses on new strategies to build catalysts more efficiently. Existing W- and Mo-based cyclic polymer catalysts require numerous steps in their syntheses. This project aims to reduce the number of synthetic steps to three or four, thereby making such catalysts more synthetically accessible, and in this way, more readily available to other researchers working in the fields of catalysis polymer chemistry. Another catalyst project centers on building tethered alkylidene catalysts from commercial sources using a novel ligand design invented at the University of Florida. The catalyst takes advantage of a new concept in metathesis chemistry that employs a double tethered metallacyclobutane functionality. More efficient, more accessible, more selective catalysts and higher catalyst activities may well be forthcoming from this work. Students participating in this research project will gain skills and knowledge important in catalyst design, polymer synthesis, and molecular characterization. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.