Designing Fluorescent Metal-Organic Supercontainers for Chemical Sensing — 30a — MaKenna King, Tilynn Campbell-Miller, Robyn Cook, Kriti Chitrakar and Dr. Zhenqiang Wang Department of Chemistry, University of South Dakota, 414 E. Clark Street, Vermillion, South Dakota 57069 

Detection of hazardous chemicals, such as illicit substances, has significant real-world implications.  Current detection protocols for these chemicals often utilize highly sensitive analytical techniques such as mass spectrometry and gas or liquid chromatography. These methods rely on advanced user knowledge and require bulky and expensive instruments. The motivation of our research is to develop a portable and  affordable alternative based on nanostructured molecules capable of selectively detecting hazardous  substances. The project focused on designing fluorescent metal-organic supercontainers (MOSCs) – a new  class of synthetic receptor molecules that feature well-defined nano-cavities suitable for binding and  sensing small molecules – as fluorescence offers precise and nondestructive characteristics highly desired  in chemical sensing. To achieve this goal, we employed an organic precursor functionalized with a  fluorescent moiety, specifically pyrene, known for its high fluorescence intensity while still providing  deep cavities for host-guest binding. Reactions of the pyrene precursor with suitable metal ions (e.g., Co²⁺) and container precursors (e.g., p–tert-butylsulfonylcalix[4]arene, TBSC) afforded a number of new MOSCs, which were characterized by various analytical techniques including X-ray crystallography,  nuclear magnetic resonance (NMR), ultraviolet-visible (UV-Vis), and fluorescent spectroscopy. Preliminary studies indicated that these new MOSCs are indeed fluorescent and that their fluorescent  emissions are sensitive to the presence of guest molecules. These new fluorescent MOSCs can thus be  used to develop a new family of chemical sensors for detecting hazardous substances through precisely tuned host-guest interactions.

University of South Dakota
Dr. Zhenqiang Wang