NSF Award
2316776
In this project managed by the Chemistry Division at NSF, Professor Trandon Bender and his students at Old Dominion University will perform studies that aim to understand fundamental organometallic processes that allow for the efficient synthesis of polymers used for developing new products like the packaging for food storage, medical devices, and building materials. Reactions combining multiple monomers result in plastics with different characteristics than those containing a single monomer. However, polymerizing ethylene with polar comonomers can form a stable chelate, limiting the incorporation of the polar monomers and decreasing the copolymerization rate. Professor Bender and his students will use a photocatalyst and visible light to break open the stable chelates and allow copolymerization to continue. They will also investigate how adding a Lewis acid to the catalyst can be used to disrupt the formation of these chelates. Their studies could lead to the synthesis of new copolymers of ethylene with varied incorporation of polar monomers and higher catalytic copolymerization reactivity. Moreover, this project will train a diverse group student from Old Dominion University along with undergraduates from Norfolk State University.<br/><br/>Professor Bender and his students will study the combination of energy transfer and catalysis using Pd- and Ni-diimine polymerization catalysts to cleave stable chelates that are formed during the copolymerization of ethylene with polar monomers such as methyl acrylate. These chelates hinder reactivity and result in low polar monomer incorporation. It is proposed that triplet-triplet energy transfer from a photocatalyst to these chelates will produce a chelate-centered triplet excited state that will promote cleavage of the chelate to achieve better incorporation and reactivity. Through modification of the diimine ligand backbones and variation of the photocatalysts, optimal conditions can be determined to modulate polar monomer incorporation, branching, and polymer size. Moreover, a ligand-tethered Lewis acid will be studied to understand how a proximal Lewis acidic center may disrupt chelate formation along with other detrimental polar monomer interactions that limit incorporation and reactivity.<br/><br/>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.
