CAS: Understanding Microenvironment Polarity in Polymers and the Effect it has on Reaction Rates and Selectivity

University Of South Carolina At Columbia, Columbia SC

Investigators

Abstract

In this project, funded by the Chemical Structure, Dynamics & Mechanisms B Program and the Established Program to Stimulate Competitive Research (EPSCoR) program, Sheryl L. Wiskur of the Department of Chemistry and Biochemistry at the University of South Carolina is developing polymers that can be used in organic reactions for the development of more sustainable chemistry. Chemists employ polymers in organic reactions to aid in the removal of products/catalysts/etc. at reaction completion to limit the amount of purification that is needed, since purification can be costly and wasteful. The problem is that reactions employing these polymers tend to suffer from diminished yield or selectivity versus when they were just run in solution. The goal of this research is to understand how the microenvironment of the polymer affects these reactions and tune that microenvironment such that yield and selectivity are retained when employing these polymers. This project incorporates organic chemistry, polymer chemistry, and supramolecular chemistry to solve this problem, and will provide a diverse training ground for graduate students and undergraduate students alike. Broader impacts also include the mentoring of women scientists to aid in retaining women in science. Since developing polymer-based chemistry is a valuable goal towards sustainable chemistry, the successful transfer of methodology to polymers is an important endeavor. Therefore, it is important to understand why chemistry transferred onto soluble polymers tend to suffer loss in selectivity and/or yield. We hypothesize that the polarity of the polymer’s microenvironment is different than the bulk solvent, which does not provide the optimal environment needed for the best results. This proposal looks at how the microenvironment polarity of the polymer can affect reaction outcomes such as yield and selectivity. Studies proposed include incorporating a solvatochromophore into functionalized polymers to understand how the functional groups affect the microenvironment polarity. Additionally, an isothiourea catalyst will be incorporated into these same functionalized polymers and used to catalyze a model reaction to understand the microenvironment effect on rate and selectivity. If successful, these studies have the potential to illuminate the optimal conditions for polymer media-based synthesis as opposed to bulk solvent-based synthesis and, as such, could have long term scientific reach in the area of sustainable chemistry. 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.