With this award, the Macromolecular, Supramolecular and Nanochemistry Program in the Division of Chemistry is funding Professor Frieder Jaekle of the Department of Chemistry at Rutgers University-Newark to explore catalytic properties of a new class of polymers that contain the chemical element boron. Artificial polymers are plastic materials consisting of many repeating molecules that are joined together by carbon-carbon bonds. Polymers benefit our society in many different ways (e.g., light-weight, easy to manufacture, and durable) and so they have become a part of everyday life. An important goal in the field of polymer science is to generate plastic materials that can be readily recycled - and this includes reshaping the materials during heat or pressure treatments. This work addresses a unique class of polymers associated with boron starting materials, instead of the usual carbon-based polymers. Boron polymers provide excellent building blocks for construction of 'smart' materials that change their original properties when exposed to external stimuli such as light, heat, pressure or chemical compounds. They may provide plastics that are more recyclable than current carbon-based materials. The project contributes to the training of a diverse group of students in a highly interdisciplinary research environment. Dr. Jaekle and his group participate in high school outreach activities and efforts at maintaining and expanding access to a polymer and nanomaterials characterization facility at Rutgers-Newark (PolyRUN).
The research team is preparing new organoborane polymers, studying their properties, and pursuing diverse applications. In the first goal, polymeric Lewis acids and 'frustrated' Lewis pairs (FLPs) are developed as supported catalysts. Tailor-made and sterically hindered, yet highly electron-deficient, triarylboranes are modified with polymerizable groups and subjected to copolymerization with monomers that feature Lewis base groups and/or substituents that facilitate polymer recovery. The copolymers are investigated in metal-free catalysis reactions such as hydrogenation and hydrosilylation of imines, aldehydes and ketones. The second goal of this work focuses on the preparation of polymers with less sterically hindered organoboranes as building blocks for supramolecular materials. When combined with Lewis base-functionalized polymers, these blocks reversibly form classical Lewis pairs as crosslinks of transient polymer networks. The last goal concentrates on the mechanochromic and stimuli-responsive properties of organoborane polymers and the synthesis of B-N analogs of polystyrene (azaborine polymers). The chemistry in this work is highly transformative with a strong potential to lead to novel materials with new functions and a breadth of applications.
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.