Physical Sciences and Mathematics Commons^™

Hierarchical Conjugated Polymer Systems Prepared By Controlled Chain-Growth Polymerization, Chunwa Peter Kei

LSU Doctoral Dissertations

π-Conjugated polymer materials may have a significant economic impact on society by providing means for designing affordable, flexible, and portable organic electronic devices. Their successful commercialization will depend on major scientific advancements, which will challenge human society to seek out ever more detailed and fundamental processes to command. Controlled polymerization affords such a power; allowing for the design of meticulous and precisely defined systems granting detailed insight into structure-property relationships in the polymer materials and bettering understanding of novel physical phenomena.

This dissertation primarily focuses on development and preparation of well-defined hierarchically organized macromolecular systems. The novel chain-growth polymerization methodologies …

Thioenamide Synthesis Inspired By Peptide Macrocycles, Joshua Allen Lutz

LSU Doctoral Dissertations

Despite advances in medicine, antibiotic resistance threatens to return once preventable diseases to the human population. The microbisporicins are 24-amino acid antibiotic peptides belonging to the lantibiotic class, which pathogens have been slow to develop resistance. The uncommon post-translational modification S-[(Z)-2-aminovinyl]-D-cysteine (AviCys) is likely crucial to their activity, and appears in a small number of other peptides with compelling biological activities. Total synthesis of an AviCys-containing peptide has eluded the chemical community.

The primary challenge of AviCys synthesis is the construction of a thioenamide functional group. We demonstrate that acid-promoted reactions between an amide and …

Turn-On Near-Infrared Fluorescent Sensors For Selective Monitoring Of Kinase Activity, Gerard Thomas Ducharme

LSU Doctoral Dissertations

Reliable and selective detection of specific biopolymers is critical in a broad range of biomedical and technological areas, including availability of simple and efficient point-of-care-compatible systems for the detection of prognostic, pharmacodynamic and predictive biomarkers. Monitoring epidermal growth factor receptor (EGFR) tyrosine kinase is of major significance due to its link to many epithelial cancers. This task is complicated by the high rate of mutation occurring in patients treated with kinase inhibitors. This dissertation describes a conceptually novel design and synthesis of turn-on near-infrared fluorescent sensors for selective and sensitive detection of EGFR. The fluorescent signal generation mechanism is based …

Chemosensors Based On Higher Energy Gap Control Of Fluorescence In Conjugated Polymers, Chun-Han Wang

LSU Doctoral Dissertations

Conjugated polymers (CPs) have been widely investigated for their remarkably high sensitivity towards various chemical detection applications. CPs can exhibit effective transduction of certain analyte binding events through changes in fluorescence. These changes include amplified fluorescence quenching ("turn-offmechanism") or an appearance of a fluorescent emission ("turn-onmechanism"). Whereas turn-offsensors can be readily designed and are widely used, amplifying turn-onsensors, from a practical standpoint, are more convenient to use but are more challenging to design.

This dissertation primarily focuses on the development and study of conjugated polymer based amplifying turn-onfluorescence chemosensors utilizing the novel “higher …

Photo-Induced Remote C-H Functionalization And New Thioglycoside Donor Development For O-Glycosylation, Shaofu Du

LSU Doctoral Dissertations

This dissertation focuses on the method development of C-H functionalization using photo-redox catalysis and the synthesis of new thioglycoside donors towards O-glycosylation. Chapter 1 describes the remote Csp³-H functionalization using photo-redox catalysis. The site-selective and high-yielding conversion of unreactive aliphatic C-H bonds has been a challenge for organic chemists for many years. In this work, inert C-H bonds were successfully converted to more useful C-C, C-N, and C-O bonds via hydrogen atom transfer (HAT), radical translocation and polar crossover. This mechanistic manifold was enacted by visible-light irradiation of o-diazoniaphenyl alkyl sulfones in the presence of Ru(bpy) …