With the support of an award from the Chemical Structure, Dynamics and Mechanism Program (CSDM) at the National Science Foundation, Professor Lei Zhu at the Florida State University will lead a research program that investigates the fundamental photophysics and coordination chemistry of fluorescent heteroditopic ligands. This work may lead to the development of fluorescent indicators for quantitative analytical applications using fluorescence microscopic means. The preliminary data from the PI's laboratory introduced the coumarin-based dual-emitting molecules as suitable structural platforms for studying the mechanism of dual emission. In the proposed work, steady state and time-resolved spectroscopic experiments will be used to reveal a kinetic model to account for dual fluorescence. Furthermore, dual fluorescence that is tunable via engineered interactions between electron acceptor moieties and a target molecule in a heteroditopic ligand framework offers opportunities for ratiometric sensor development. The proposed investigations on the fluorescent heteroditopic ligands containing a spirolactam form of rhodamine shall reveal the factors that govern the efficiency of intramolecular electron transfer of spirolactam-containing fluorophores, and the kinetics of spirolactam ring-opening. Resolving these two issues will advance the fundamental understanding on the rhodamine spirolactam chemistry, which provides a sound basis for incorporating rhodamine spirolactam in a sensor structure.
This award to Professor Zhu at the Florida State University will lead to results that enrich the knowledge base on the fundamental molecular photophysics and coordination chemistry. Furthermore, tunable dual-fluorescing heteroditopic ligands can be developed into ratiometric fluorescent sensors when a specific interaction between the fluorophore and a target molecule is designed into the fluorophore structure. Investigations on the rhodamine spirolactam chemistry and the metal-coordination dependent ring-opening kinetics will aid further sensor development based on this system with a largest possible signal-to-noise ratio. Some of the broader impacts of the proposed activities derive from the PI's commitment to teaching, and to advocating the dissemination of cutting-edge scientific research to the broader public. With the support of this award, a course on the societal/cultural interests on chemical research to chemistry majors and graduate students will be developed. The chemistry- and graduate education-related contents from motion pictures and chemistry-related blogs will be used as teaching materials for training young science communicators to the public at large.
