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1.
Phun, Lien Hoang.
Innovative approaches to carbocyclic and heterocyclic compounds using strained carbocycles.
Degree: PhD, Chemistry and Biochemistry, 2013, Georgia Tech
URL: http://hdl.handle.net/1853/47542 
► Natural products and small molecules play a major role in drug development. However, using natural products as a source of medicine comes with many challenges,…
(more)
▼ Natural products and small molecules play a major role in drug development. However, using natural products as a source of medicine comes with many challenges, such as lack of natural abundance and difficulty in isolation. Consequently, synthetic organic chemistry is a solution in order to access these compounds in usable quantities. However, synthetic chemisty comes with its own challenges such as efficiency, chemoselectivity, stereoselectivity and enantioselectivity. Therefore, synthetic tools that addresses these challenges are required solve these limitations. This thesis discusses new methodologies using strained carbocycles (cyclopropanes and cyclopropenes) as the reactive subunit for the construction of different carbocyclic and heterocyclic compounds. The homo-Nazarov cyclization of alkenyl and heteroaryl cyclopropyl ketones was used in order to construct cyclohexenones, cyclohexenols, heteroaryl ring-fused cyclohexenones, dihydrofurans, furans and furanones in a mild and efficient manner. Benzofused heteroaromatic compounds were achieved via the Lewis acid-catalyzed cycloisomerization of cyclopropene-3,3-dicarbonyls and furan-3-carboxylates. These heteroaromatic compounds can be applied to medicinal chemistry and material science.
Advisors/Committee Members: [email protected] (Committee Chair), charles liotta (Committee Member), christoph fahrni (Committee Member), david collard (Committee Member), julia kubanek (Committee Member).
Subjects/Keywords: Furans; Carbocycles; Heterocycles; Cyclopropane; Cyclopropene; Diazo; Drug development; Pharmacognosy
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APA (6th Edition):
Phun, L. H. (2013). Innovative approaches to carbocyclic and heterocyclic compounds using strained carbocycles. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/47542
Chicago Manual of Style (16th Edition):
Phun, Lien Hoang. “Innovative approaches to carbocyclic and heterocyclic compounds using strained carbocycles.” 2013. Doctoral Dissertation, Georgia Tech. Accessed January 24, 2021.
http://hdl.handle.net/1853/47542.
MLA Handbook (7th Edition):
Phun, Lien Hoang. “Innovative approaches to carbocyclic and heterocyclic compounds using strained carbocycles.” 2013. Web. 24 Jan 2021.
Vancouver:
Phun LH. Innovative approaches to carbocyclic and heterocyclic compounds using strained carbocycles. [Internet] [Doctoral dissertation]. Georgia Tech; 2013. [cited 2021 Jan 24].
Available from: http://hdl.handle.net/1853/47542.
Council of Science Editors:
Phun LH. Innovative approaches to carbocyclic and heterocyclic compounds using strained carbocycles. [Doctoral Dissertation]. Georgia Tech; 2013. Available from: http://hdl.handle.net/1853/47542
2.
Rolle, Clarence J.
Selective aerobic oxidations catalyzed by manganese(III) complexes using redox-active ligands.
Degree: PhD, Chemistry and Biochemistry, 2011, Georgia Tech
URL: http://hdl.handle.net/1853/42827
► Selective oxidations are important for the functionalization of compounds in organic synthesis and chemical industry. Using O2 as a terminal e- acceptor would be ideal…
(more)
▼ Selective oxidations are important for the functionalization of compounds in organic synthesis and chemical industry. Using O2 as a terminal e- acceptor would be ideal because it is cheap and environmentally friendly, but aerobic oxidations are often prone to unselective free radical autoxidation. Recently developed palladium catalysts use O2 as a selective multi-electron oxidant for various organic transformations. Although these methods are powerful and sophisticated, the lower cost of base metals makes them attractive as potential alternatives. The challenge is to develop methods for effecting multi-electron transformations at metals that typically prefer one electron changes. To this end, the development of manganese(III) complexes containing redox-active ligands as catalysts for selective oxidase-type oxidation of organic substrates was pursued. Bis(tetrabromocatecholato) manganese(III) complexes were shown to aerobically oxidize catechols to form quinones and H2O2. This reactivity was extended to other alcohol and amine substrates. In these reactions, the non-innocent tetrabromocatecholate ligands may impart a multi-electron character to the metal. To directly probe the intermediacy of ligand-centered radicals in catalytic turnover, a series of structurally similar manganese(III) complexes with aminophenol-derived ligands were prepared and characterized. The capacity of these ligands to undergo low-energy redox changes, allowed for isolation of an electron transfer series spanning two redox states without a change in oxidation state at the metal center. The ligand-centered redox events were a key feature in aerobic homocoupling of Grignard reagents.
Advisors/Committee Members: Jake Soper (Committee Chair), Angus Wilkinson (Committee Member), Christoph Fahrni (Committee Member), Christopher Jones (Committee Member), Kent Barefield (Committee Member).
Subjects/Keywords: Oxidation chemistry; Metal catalysts; Metalloenzymes; Manganese; Manganese catalysts; Oxidases; Oxidation
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APA (6th Edition):
Rolle, C. J. (2011). Selective aerobic oxidations catalyzed by manganese(III) complexes using redox-active ligands. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/42827
Chicago Manual of Style (16th Edition):
Rolle, Clarence J. “Selective aerobic oxidations catalyzed by manganese(III) complexes using redox-active ligands.” 2011. Doctoral Dissertation, Georgia Tech. Accessed January 24, 2021.
http://hdl.handle.net/1853/42827.
MLA Handbook (7th Edition):
Rolle, Clarence J. “Selective aerobic oxidations catalyzed by manganese(III) complexes using redox-active ligands.” 2011. Web. 24 Jan 2021.
Vancouver:
Rolle CJ. Selective aerobic oxidations catalyzed by manganese(III) complexes using redox-active ligands. [Internet] [Doctoral dissertation]. Georgia Tech; 2011. [cited 2021 Jan 24].
Available from: http://hdl.handle.net/1853/42827.
Council of Science Editors:
Rolle CJ. Selective aerobic oxidations catalyzed by manganese(III) complexes using redox-active ligands. [Doctoral Dissertation]. Georgia Tech; 2011. Available from: http://hdl.handle.net/1853/42827
3.
Choi, Sungmoon.
Fluorescent noble metal nanodots for biological applications.
Degree: PhD, Chemistry and Biochemistry, 2010, Georgia Tech
URL: http://hdl.handle.net/1853/37195
► Commercial organic dyes are widely used for cellular staining due to their small size, high brightness, and chemical functionality. However, their blinking and photobleaching are…
(more)
▼ Commercial organic dyes are widely used for cellular staining due to their small size, high brightness, and chemical functionality. However, their blinking and photobleaching are not ideal for studying dynamics inside live cells. An improvement over organics and much larger quantum dots, silver nanodots (Ag NDs) exhibit low cytotoxicity and excellent brightness and photostability, while retaining small size. We have utilized ssDNA hairpin structures to encapsulate Ag NDs with excellent spectral purity, high concentration, and good chemical and photophysical stability in a variety of biological media. Multi-color staining of fixed and live cells has been achieved, suggesting the promise of Ag NDs as good fluorophores for intracellular imaging. The great brightness and photostability of Ag nanodots indicate that they might be outstanding imaging agents for in vivo studies when encapsulated in delivery vehicles. In addition, Ag NDs can be optically modulated, resulting in increased sensitivity within high backgrounds. These good characteristics are combined with delivery vehicles such as PLGA and nanogels. After encapsulation, Ag nanodots still retain their good photophysical properties and modulation. It might be useful for in vivo applications in the near future
Advisors/Committee Members: Robert M. Dickson (Committee Chair), Christoph Fahrni (Committee Member), L. Andrew Lyon (Committee Member), Mostafa A. El-Sayed (Committee Member), Niren Murthy (Committee Member).
Subjects/Keywords: DNA; Nanodots; Drug delivery; Cellular staining; Fluorophores; Silver; Drug delivery systems; Biomedical materials Imaging compatibility; Diagnostic imaging
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APA (6th Edition):
Choi, S. (2010). Fluorescent noble metal nanodots for biological applications. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/37195
Chicago Manual of Style (16th Edition):
Choi, Sungmoon. “Fluorescent noble metal nanodots for biological applications.” 2010. Doctoral Dissertation, Georgia Tech. Accessed January 24, 2021.
http://hdl.handle.net/1853/37195.
MLA Handbook (7th Edition):
Choi, Sungmoon. “Fluorescent noble metal nanodots for biological applications.” 2010. Web. 24 Jan 2021.
Vancouver:
Choi S. Fluorescent noble metal nanodots for biological applications. [Internet] [Doctoral dissertation]. Georgia Tech; 2010. [cited 2021 Jan 24].
Available from: http://hdl.handle.net/1853/37195.
Council of Science Editors:
Choi S. Fluorescent noble metal nanodots for biological applications. [Doctoral Dissertation]. Georgia Tech; 2010. Available from: http://hdl.handle.net/1853/37195
Georgia Tech
4.
Thaler, Tracey Lyn.
Search for Extraterrestrial Life using Chiral Molecules: Mandelate Racemase as a Test Case.
Degree: PhD, Chemistry and Biochemistry, 2007, Georgia Tech
URL: http://hdl.handle.net/1853/14527
► The possible existence of extraterrestrial life forms has been of interest to humans for many millennia. In the past few decades space travel has provided…
(more)
▼ The possible existence of extraterrestrial life forms has been of interest to humans for many millennia. In the past few decades space travel has provided an opportunity to search life outside of Earth. Chiral molecules are critical molecules in Earth-based life and are among the first chemical molecules sought after as proof of potential extraterrestrial life; however, identification of these chiral molecules is difficult due the lack of sensitive instruments. The objective of this work is to develop a benchmark reaction to be used as a guide in the development of instrumentation, such as a polarimeter, to be used in the search for extraterrestrial life. To achieve this objective, to investigate the enzyme mandelate racemase (MR), which catalyzes the racemization between the enantiomers of mandelate. MR is a member of the enolase superfamily, which contains a (alpha/beta)7-b barrel domain, the fold most frequently found among all known protein structures.
Activity of the enzyme was measured at low temperatures and in non-aqueous media, as these are the conditions that represent extraterrestrial terrain. We find that mandelate racemase (MR) is active in concentrated ammonium salt solutions and water-in-oil microemulsions in a temperature range between 30C to 70C; however, the enzyme is not active in several organic cryosolvents. The stability of the structure of MR was also explored. Using differential scanning calorimetry (DSC) we observe the unfolding of the enzyme was irreversible and therefore kinetically controlled. We also found proof for divergent evolution of the enolase superfamily, providing evidence for divergent evolution across the MR and muconate lactonizing enzyme (MLE) subfamilies has been demonstrated. However, we also conclude that reactions yielding a polarimetric signal, such as racemizations employed in this work, are suitable as a tool to find signs of life.
Advisors/Committee Members: Andreas Bommarius (Committee Chair), Christoph Fahrni (Committee Member), Donald Doyle (Committee Member), Phillip Gibbs (Committee Member), Rick Trebino (Committee Member).
Subjects/Keywords: Irreversible protein denaturation; Enzymatic reactivity at subzero temperatures; Enolase superfamily; Polarimetric assay
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APA ·
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APA (6th Edition):
Thaler, T. L. (2007). Search for Extraterrestrial Life using Chiral Molecules: Mandelate Racemase as a Test Case. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/14527
Chicago Manual of Style (16th Edition):
Thaler, Tracey Lyn. “Search for Extraterrestrial Life using Chiral Molecules: Mandelate Racemase as a Test Case.” 2007. Doctoral Dissertation, Georgia Tech. Accessed January 24, 2021.
http://hdl.handle.net/1853/14527.
MLA Handbook (7th Edition):
Thaler, Tracey Lyn. “Search for Extraterrestrial Life using Chiral Molecules: Mandelate Racemase as a Test Case.” 2007. Web. 24 Jan 2021.
Vancouver:
Thaler TL. Search for Extraterrestrial Life using Chiral Molecules: Mandelate Racemase as a Test Case. [Internet] [Doctoral dissertation]. Georgia Tech; 2007. [cited 2021 Jan 24].
Available from: http://hdl.handle.net/1853/14527.
Council of Science Editors:
Thaler TL. Search for Extraterrestrial Life using Chiral Molecules: Mandelate Racemase as a Test Case. [Doctoral Dissertation]. Georgia Tech; 2007. Available from: http://hdl.handle.net/1853/14527
Georgia Tech
5.
Nicovich, Philip R.
Widefield fluorescence correlation spectroscopy.
Degree: PhD, Chemistry and Biochemistry, 2010, Georgia Tech
URL: http://hdl.handle.net/1853/33849
► Fluorescence correlation spectroscopy has become a standard technique for modern biophysics and single molecule spectroscopy research. Here is presented a novel widefield extension of the…
(more)
▼ Fluorescence correlation spectroscopy has become a standard technique for modern biophysics and single molecule spectroscopy research. Here is presented a novel widefield extension of the established single-point technique. Flow in microfluidic devices was used as a model system for microscopic motion and through widefield fluorescence correlation spectroscopy flow profiles were mapped in three dimensions. The technique presented is shown to be more tolerant to low signal strength, allowing image data with signal-to-noise values as low as 1.4 to produce accurate flow maps as well as utilizing dye-labeled single antibodies as flow tracers. With proper instrumentation flows along the axial direction can also be measured. Widefield fluorescence correlation spectroscopy has also been utilized to produce super-resolution confocal microscopic images relying on the single-molecule microsecond blinking dynamics of fluorescent silver clusters. A method for fluorescence modulation signal extraction as well as synthesis of several novel noble metal fluorophores is also presented.
Advisors/Committee Members: Dickson, Robert (Committee Chair), Christoph Fahrni (Committee Member), El-Sayed, Mostafa (Committee Member), Lyon, Andrew (Committee Member), Srinivasarao, Mohan (Committee Member).
Subjects/Keywords: Correlation spectroscopy; Super resolution microscopy; Single molecule spectroscopy; Velocimetry; Microfluidics; Fluorescence spectroscopy; Spectrum analysis; Flow visualization; Axial flow; Image analysis
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APA ·
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APA (6th Edition):
Nicovich, P. R. (2010). Widefield fluorescence correlation spectroscopy. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/33849
Chicago Manual of Style (16th Edition):
Nicovich, Philip R. “Widefield fluorescence correlation spectroscopy.” 2010. Doctoral Dissertation, Georgia Tech. Accessed January 24, 2021.
http://hdl.handle.net/1853/33849.
MLA Handbook (7th Edition):
Nicovich, Philip R. “Widefield fluorescence correlation spectroscopy.” 2010. Web. 24 Jan 2021.
Vancouver:
Nicovich PR. Widefield fluorescence correlation spectroscopy. [Internet] [Doctoral dissertation]. Georgia Tech; 2010. [cited 2021 Jan 24].
Available from: http://hdl.handle.net/1853/33849.
Council of Science Editors:
Nicovich PR. Widefield fluorescence correlation spectroscopy. [Doctoral Dissertation]. Georgia Tech; 2010. Available from: http://hdl.handle.net/1853/33849
. 
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