Physical Sciences and Mathematics Commons^™

Photocatalytic Degradation Of Lignin By Supported Silver Nanoparticles, Ning Wei

Theses and Dissertations--Chemical and Materials Engineering

Lignin is the second most abundant form of biomass on earth. The phenolic structure and high carbon to oxygen ratio make lignin an attractive renewable source of fuel and chemicals. However, its recalcitrance and heterogeneous nature prove difficult for decomposing lignin’s polymer structure and separation of the products. This work has focused on the use of low-energy catalytic approaches to overcome these barriers. A mimic of the lignin degrading enzyme laccase, consisting of a copper cluster Cu4Py4I4 modified with AgNO3, was developed to function similarly to the laccase active site. The prepared copper complex solution was found to be active …

1,2-Diamination Of Alkenes Via Reduction Of 1,2,3-Triazolinium Ions, Setareh Saryazdi

Theses and Dissertations--Chemistry

1,2-Diamine substructures are prevalent functional motifs in natural products, pharmaceutical compounds, and ligands. The interesting functionalities of 1,2-diamines have inspired many synthetic chemists to design various methodologies for preparing these structures from simple precursors such as alkenes. In this work, we described two different but related methods using simple and easily accessible reagents for 1,2-diamination of alkenes. In the first method, an alkene undergoes 1,3-dipolar cycloaddition with an organic azide to form a 1,2,3-triazoline. Subsequent N-alkylation of the generated 1,2,3-triazoline gives the 1,2,3-triazolinium ion, which is then hydrogenated over Raney Ni with a balloon of H₂ to produce …

Application Of Mass Spectrometry For Characterization Of Plant-Based Phenolics And Alkaloids, Masoumeh Dorrani

Theses and Dissertations--Chemistry

Plant-derived compounds have the potential to produce value-added compounds with a variety of applications. For example, the lignin part of the lignocellulosic biomass, produced in large quantities as waste from the paper and pulp industries, is a rich source of phenolics with potential applications in the renewable energy sector, pharmaceutical, and chemical industries. On the other hand, plant alkaloids are the primary source for developing plant-derived therapeutics. Unfortunately, the recalcitrant nature of plant cell walls, low extraction yields of small secondary metabolites, and the lack of effective analytical methods for a rapid and accurate identification of plant-based compounds and plant’s …

Crystal Engineering Of Asymmetric And Pyrene Fused Annulenes For Use In Organic Electronic Materials, Garrett Fregoso

Theses and Dissertations--Chemistry

Since the development of TiPS Pentacene, the use of trialkylsilylethynyl groups has become a commonly utilized moiety for stabilizing, solubilizing, and directing crystal packing of acenes and acene-like compounds, leading to the development of a well-defined series of trends that aid in the prediction of crystal packing for the development of organic semiconducting materials. While these trends have been extensively studied in mainly symmetric linear systems, it is important to determine how, if at all, asymmetry of the aromatic core affects these well-defined trends. This constitutes the basis of Chapter 2, which explores the crystal engineering and physical properties of …

Synthesis Of 6,6- And 7,7-Difluoro-1-Acetamidopyrrolizidines And Their Oxidation Catalyzed By The Nonheme Fe Oxygenase Lolo, Nabin Panth

Theses and Dissertations--Chemistry

One of the remarkable steps in loline alkaloid biosynthesis is the installation of an ether bridge between two unactivated C atoms in 1-exo-acetamidopyrrolizidine (AcAP). LolO, a 2-oxoglutarate-dependent nonheme Fe oxygenase, catalyzes both the hydroxylation of AcAP and the resulting alcohol's cycloetherification to give N-acetylnornoline (NANL). The mechanism of hydroxylation is well understood, but the mechanism of the oxacyclization is not. I synthesized difluorinated analogs of AcAP in an attempt to further understand the mechanism of the unusual cycloetherification step.

I prepared 6,6-F₂-AcAP in eight steps from N,O-protected 4-oxoproline. The key step was a Dieckmann …