Chemistry Theses and Dissertations

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https://hdl.handle.net/1794/2046

This collection contains some of the theses and dissertations produced by students in the University of Oregon Chemistry Graduate Program. Paper copies of these and other dissertations and theses are available through the UO Libraries.

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Browsing Chemistry Theses and Dissertations by Author "Banning, Douglas"

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    Fresh Approach for High-Throughput Studies of Ion-Selective Materials Using Reusable ChemFET Platform
    (University of Oregon, 2019-04-30) Banning, Douglas; Johnson, Darren
    Aqueous anions play an important role in our world, and the ability to continuously measure them provides both environmental and health benefits. Chemically-sensitive field effect transistors (ChemFETs) are becoming increasingly popular in the field of aqueous measurement due to their relatively low-cost capability for real-time, continuous sensing. Receptor molecules or mixtures displaying affinity for a particular ion can also be utilized in a ChemFET gate membrane. Receptors can be incorporated into the gate oxide membrane and the entire ChemFET can utilized in an aqueous environment, thus utilizing hydrophobic receptors in an aqueous anion-sensing application. Demonstrating the ability to reuse the sensors validates an important characteristic for ChemFET-based research. Additionally, numerous other receptor molecules are evaluated against an array of common anions. Selectivity coefficients are compared to the Hofmeister Series. Additional membranes are evaluated for suitability for incorporation of receptors on the ChemFET gate oxide surface. This thesis includes previously unpublished co-authored material.
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    Fresh Quantitative Approaches for High-Throughput Characterization Using ChemFETs and Statistical Analysis
    (University of Oregon, 2025-02-24) Banning, Douglas; Banning, Douglas
    Anion receptors are an increasingly important area of focus in synthetic organic chemistry, especially in areas such as environmental pollution detection and remediation. Many organic anion receptors are hydrophobic, limiting their utility for direct evaluation of aqueous anion affinity. Electrochemical sensors such as chemically-sensitive field effect transistors (ChemFETs) can bridge this gap. Incorporation of anion receptors into the chemically sensitive membrane of a ChemFET can facilitate direct measurement of aqueous anion affinity of hydrophobic sensors. One key piece of information that this can elucidate is the relative affinities of anions with the host by direct comparison of detection limits for each anion. Relative ranking of anion detection limits can be compared to the Hofmeister series, especially useful for determining the placement of relatively unknown, reactive species into the Hofmeister series.Dodeca-n-butyl bambus[6]uril was used in the selective membrane of a ChemFET to produce the first reported placement of hydrosulfide in the Hofmeister series. The contribution of the binding pocket geometry on anion affinities was then explored by comparing anion detection limits of dodeca-n-butyl bambus[6]uril with dodecabenzyl bambus[6]uril. The utility of ChemFETs was then expanded to assess the anion affinity of metal organic frameworks (MOFs), to learn about the anion binding nature of a novel MOF. After studying the nature of host-guest interactions using electrochemical sensors, research efforts expanded to include a statistically-based analytical method for characterization of synthetic pathways. Design of experiments (DOE) is generally used to characterize processes, and quantify impacts of main and multi-factor interactions on desired outputs. In chemical applications, DOE can characterize syntheses, specifically the impacts of each factor (together or in isolation) on the resulting product. This information can then be used to provide optimization conditions to produce desired properties. Significantly, this evaluation technique can be applied to historical data in order to characterize reactions before running any new experiments. In this particular case, flat aluminum 13 (f-Al13) cluster was analyzed via DOE in an effort to optimize desired properties. This data was then used to provide optimization conditions for the factors of size (minimize) and polydispersity index (minimize). Two different sets of optimization conditions were used as a validation run to synthesize aluminum particles, demonstrating a drastic improvement in one of the two optimization conditions. Finally, other research efforts are examined and documented. These efforts include ChemFET characterization of anion receptors, synthetic challenges, and application of DOE to characterize and optimize reactions. Overall, this dissertation involves the coalescence of different areas of study in order to solve difficult problems.