Evaluation of Steric Effects for Faster BEPs (BODIPY Ethylene Probes)

Ethylene is a hormone released during key life cycle events in plants and commonly associated with fruit ripening. Recently, the Michel Group has reported fluorescent small molecule probes for the detection of ethylene through a selective reaction-based approach. To improve the sensitivity and selectivity of these probes, it is necessary to synthesize analogues and evaluate how structural changes will influence their photophysical properties such as limit of detection and fluorescence turn-on. A series of advancements upon original BODIPY Ethylene Probes BEP-4 and BEP-5 have provided evidence that faster reaction kinetics results in a probe that is more sensitive to ethylene. To further evaluate this hypothesis, we developed a synthetic route for a target probe BEP-3, with the goal of determining if steric effects would significantly impact ethylene sensitivity. Early photophysical data on BEP-3 demonstrates rapid reaction with ethylene and a turn-on with ethylene similar to previous fast-initiating probes in the Michel Lab. Additional evaluation of the ethylene detection ability of BEP-3 will be presented including limit of detection and kinetic profile data.