CAS: CAREER: Bridging Photoacids and Photobases with Schiff base Platforms

Bowdoin College, Brunswick ME

Investigators

Abstract

In this CAREER project, jointly funded by the Chemical Structure, Dynamics & Mechanisms-B (CSDM-B) Program of the Chemistry Division and the Established Program to Stimulate Competitive Research (EPSCoR), Kana Takematsu of the Department of Chemistry and Biochemistry at Bowdoin College is developing new classes of molecules that are designed to undergo the exchange of protons in response to light. The light-initiated movement of protons has myriad chemical implications, including in the harnessing of solar energy. The goal of this research is to study how the chemical characteristics of these molecules and their environment affect their ability to exchange protons effectively, information that will be used to design photo-acids and photo-bases for targeted applications. The project will be conducted by a team of undergraduate students from diverse backgrounds, supporting an inclusive research culture that fosters science identity and belonging in students. Laboratory modules will be created and embedded into courses to introduce students to the field of photochemistry, and students will have the opportunity to become part of the broader scientific community through collaborative research projects and meetings. Photo-acids and photo-bases allow temporal and spatial control of proton donation and abstraction via light. Designing photo-acids and photo-bases for desired applications requires a fundamental understanding of the driving forces and solvent parameters that promote excited state proton transfer (ESPT). The proposed project utilizes the chemical modularity of Schiff base chemistry to build photo-acids and photo-bases for detailed mechanistic studies of ESPT and excited state intramolecular proton transfer. Inherent in this design is a carbon-nitrogen double bond capable of photo-isomerization that can potentially trigger a structural rearrangement coupled to ESPT. In this project, Aim 1 will test whether the Schiff base template provides a suitable scaffold for naphthol photo-acid derivatives. Aim 2 will test whether the Schiff base template provides a suitable scaffold for quinoline photo-base derivatives. And Aim 3 builds on these platforms to test whether carbon-nitrogen double bond photo-isomerization can be coupled to ESPT through addition of pyridine-based proton acceptors and phenol-based proton donors to the scaffold. 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.