Collaborative research: stimuli responsive charge-transfer complexes for measuring solvophobic effects and chiral recognition of amines

The National Science Foundation Directorate for Mathematical and Physical Sciences awarded Converse University $190,000 on September 15, 2026, under the Mathematical and Physical Sciences program (CFDA 47.049) to design and study stimuli-responsive charge-transfer complexes that change color upon non-covalent interactions with solvent molecules and chiral molecules. The research aims to develop molecular sensors providing visual methods for studying molecular interactions without specialized instrumentation, and to generate optical probes for quantifying solvent effects in environments where conventional NMR methods are impractical. The collaborative project between Converse University and the University of South Carolina will design donor-acceptor systems incorporating amino acid-based recognition elements that produce distinct colorimetric responses upon binding enantiomeric diamines, supported by experimental and computational studies. Work is performed in Spartanburg, South Carolina, with a period of performance extending through August 31, 2029. The project will expand undergraduate research opportunities at Converse University, provide interdisciplinary research training to graduate and undergraduate students, develop demonstration materials for classroom teaching and outreach activities, and promote faculty development through shared resources and co-mentorship between the collaborating institutions.

Abstract

This collaborative project between the university of south carolina and converse university aims to design and study a new class of stimuli-responsive motifs that change color upon non-covalent interactions with surrounding solvent molecules or specific chiral molecules. These motifs may serve as molecular sensors, providing simple visual methods for studying molecular interactions that currently require specialized instrumentation. The fundamental chemistry knowledge from this research will inform the future design and advanced manufacturing of new stimuli-responsive materials and supramolecular sensors. The collaboration will expand undergraduate research opportunities at converse university, provide interdisciplinary research training to graduate and undergraduate students, and promote reciprocal faculty development through shared resources and CO-mentorship. IT will also develop demonstration materials for teaching in classrooms, laboratory experiments, and outreach activities based on color-changing molecules. The project will develop donor-acceptor systems in which intramolecular charge-transfer interactions generate visible color changes that depend on molecular conformation. The research team will correlate solvent-dependent changes in charge-transfer absorption with solvent cohesive energy density, providing optical probes for quantifying solvent effects in environments where conventional NMR methods are impractical. The donor-acceptor framework will then be extended to incorporate amino acid-based recognition elements that generate distinct colorimetric responses upon binding enantiomeric diamines. Through a combination of experimental and computational studies of these supramolecular systems, this research aims to provide fundamental knowledge in PI-stacked donor-acceptor interactions and establish general design principles for future development of stimuli-responsive materials and colorimetric molecular sensors based on conformationally controlled charge-transfer interactions. 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.- subawards are not planned for this award.