Document Type

Thesis

Date of Award

2024

Degree Name

Master of Science (MS)

Department

Chemistry

First Advisor

Zhenqiang Wang

Abstract

Illicit and hazardous substances pose a serious effect on the human body which can create longer-term issues on the mental and physical health which potentially lead to fatalities. Current methods for detecting illicit substances include analytical techniques like mass spectrometry (MS) and gas/liquid chromatography (GC/LC) which are known for accuracy and sensitivity. However, these instruments are bulky, costly, time-consuming, and require highly trained personnel. An alternative approach to overcoming these limitations is to employ nanostructured molecule-based chemical sensing technologies that are user-friendly, portable, and cost-effective with the sensitivity for detecting illicit substances. One such candidate is metal-organic super-containers (MOSCs), which represent a new class of synthetic receptor molecules that self-assemble to form well-defined nano-cavities suitable for binding and sensing small molecules. MOSCs are a particularly attractive element for chemical sensing due to their diverse topologies, tunable chemical properties, and ease of controlling size and shape of their nano-cavities. The main motivation of this research is focused on designing fluorescent MOSCs as a key component of chemical sensors that can detect and monitor illicit and hazardous substances such as methamphetamine. The strategy centers on functionalizing MOSCs with rigid and planar extended aromatic moieties such as pyrene groups, a known fluorophore, to impart multifunctionalities, including deeper nano-cavities for more targeted analyte binding, and stronger fluorescent properties. A new series of fluorescent MOSCs have been designed and characterized, confirming the complete formation of MOSC assembly through an array of instrumentations such as single-crystal x-ray diffraction (SC-XRD) and thermogravimetric analysis (TGA), resulting in MOSCs with incorporated pyrenyl units. The fluorescent properties within MOSCs were thoroughly investigated using fluorescence spectroscopy. These fluorescently functionalized MOSCs demonstrated unique fluorescent properties by displaying pyrenes characteristic emission bands. These findings confirm that new MOSCs can be designed with the incorporation of additional fluorophore moieties that can be taken advantage of for chemical sensing applications. Future studies will examine the multifunctional characteristics of MOSCs, potentially leading to a new class of fluorescent chemical sensing technologies for illicit substances with high sensitivity, selectivity, and portability.

Subject Categories

Chemistry | Materials Chemistry | Organic Chemistry

Keywords

Fluorescence spectroscopy, Fluorescent chemical sensing, Fluorescent MOSCs, Illicit drugs Metal-organic supercontainers (MOSCs), Organic ligand modifications

Number of Pages

108

Publisher

University of South Dakota

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