Date of Award
Master of Science
Although the chemical and physical properties of enantiomers are identical, they exhibit different biological activities. Therefore, one enantiomer often shows maximum therapeutic activity, but the other enantiomer may have no effect, inhibit the ability of the therapeutic form, or can even be harmful. Since enantiomers can be found in different area, such as drugs, pesticides, waste compounds, etc, it is important and necessary to develop simple, fast, low cost, and accurate methods for determination of enantiomeric composition. Xu and McCarroll have developed a method to determine enantiomeric composition by steady-state fluorescence anisotropy based on guest and host theory, where the guest is the chiral analyte, and the host is the chiral selector. The first part of this thesis is an extension of this study investigating different chiral analytes. The chiral selectors that were chosen for this study are different sizes of cyclodextrins, and the chiral analytes that were selected to examine are binaphthyl derivatives, which are 1, 1'-bi-2-napththol (BOH), 1, 1'-binaphthyl-2, 2'-diyl hydrogen phosphate (BNP), and propanol hydrochloride. β-cyclodextrin (CD) was found to be a better chiral selector for determination of BNP enantiomeric composition in this system. Moreover, the chiral selector that was better for determination of BOH and propanol hydrochloride enantiomeric composition in the study was found to be α-CD and γ-CD, respectively. A temperature study was carried out to investigate the best temperature for the determination of BNP enantiomeric composition with β-CD as the chiral selector, and 10 °C was found to be the best temperature in the system. Following an unexpected observation of new species found to be produced after light exposure, a detailed study was applied in order to determine the possible mechanism of the reactions and the identity of the various chemical structures. This investigation is of relevance since BNA is used in various applications and was mentioned in the second part of this thesis. Beside fluorescence spectroscopy, other techniques were applied in this study, such as laser desorption/ionization mass spectrometry (LSI-MS), ultraviolet-visible spectroscopy (UV-Vis), nuclear magnetic resonance spectroscopy (NMR), and thin layer chromatography (TLC). There were 5 possible species that were determined when BNA in chloroform was exposed to 377 nm light, which are hypothesized as 7H-Dibenzo[c,g]carbazole (DBC), 7, 8-Diazahelicene N.N'-Dioxide produced through oxidation and three additional compounds formed through excited state proton transfer (ESPT). Evidence supporting these hypotheses is discussed, as well as the need for further study to confirm the structures of the various species produced during light exposure.
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