Doctor of Philosophy (PhD)
This dissertation focuses on the diverse use of chemical synthesis. Herein, I will discuss the use of synthetic organic chemistry for the modification surfaces and the synthesis of small molecules. Chapter One is an introduction to the realm of surface chemistry. I have highlighted some key methods for surface modification. Additionally, methods to characterize the as-formed thin films are also outlined. In Chapter Two, I discuss the use of visible-light photoredox catalysis in the nanoscale lithography of Au(111) surfaces. Blue LED irradiation of solutions of NBDT in the presence of Ru(bpy)32+ results in the formation of p-nitrophenyl radicals that graft onto Au. Further reaction of the grafted arenes with aryl radicals results in oligomerization to polyphenylene structures with resulting film thicknesses that are dependent on both the initial concentration of diazonium salt and the duration of the grafting procedure. Grafting onto Au(111) coated with SiO2 mesospheres (d = 500 nm) prior to mesospheres removal results in the production of nanopatterned surfaces wherein each nanopore represents the former location of a mesosphere. Chapter Three focuses on the a novel use of visible light photoredox catalysis for organic thin film formation with nanoscale lithography of Au(111) surfaces. Irradiation of solutions of phthalimide esters with blue LEDs in the presence of the Ru(bpy)3Cl2 results in the formation of carbon centered radicals that form organic thin films. We propose that a series of additional reactions of the grafted aliphatic chains with alkyl radicals results in oligomerization and the formation of multilayers. Chapter Four is a brief discussion of the significance of oligosaccharide synthesis. The development of efficient and stereoselective methods for glycosylation is a synthetic challenge. Thioglycosides are inert to many glycosylation methods and are bench top stable. Their stability to common carbohydrate protecting group manipulations makes thioglycosides ideal glycosyl donors or acceptors. Traditionally, the activation of thioglycosides requires heavy metals, halogen electrophiles, or stoichiometric thiophilic reagents. In contrast, our method discussed in Chapter 5 requires catalytic Bronsted acid for the remote activation of a thioglycoside donor. Under these conditions, O-glycosylation formation and release of a tetrahydrothiophene aglycon is swift and high yielding.
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Release the entire work immediately for access worldwide.
Quarels, Rashanique Deondria, "Chemical Synthesis: New Methods for O-Glycosylation and the Preparation of Organic Thin Films" (2017). LSU Doctoral Dissertations. 4321.