Other Chemistry Commons^™

Supramolecular Pi-Donor/Acceptor Arrays Based On Redox-Active Metal-Organic Coordination Assemblies, Paola Benavides

All Dissertations

Coordination-driven self-assembly is an attractive strategy for constructing thermodynamically stable supramolecular coordination complexes, ranging from discrete metallacycles and cages to infinite coordination polymers and metal-organic frameworks for a variety of applications.

Chapter 1 discusses strategies for preparing supramolecular charge-transfer π-donor/acceptor assemblies and their potential applications.

Chapter 2 demonstrates that tricomponent self-assembly method, which was believed to yield 3D-cages, based on tetrapyridyl porphyrin (M’TPP, M’ = Zn or H₂), dicarboxylate ligands (XDC), and caped cis-Pt(II) corners, actually yields 2D-bowties featuring an M’TPP core and two parallel XDC linkers held together by four heteroligated PtII(N,O) corners. The 2D-bowties showed …

The Impact Of Glacial Proximity On The Elemental Composition Of Leachate Derived From Sediment Weathering, Karoline Ford

Theses/Capstones/Creative Projects

This study assesses chemical weathering trends as they relate to glacial retreat. The chemical environment of surfaces exposed to the atmosphere differs significantly from beneath a glacier. As a glacier melts, changes to the biogeochemical processes generate environmental gradients. This study analyzed chemical weathering signals at different distances from a glacial front by comparing the elemental composition of leachate derived from sediments in southeastern Greenland. Samples from proglacial, nonglacial, and moraine locations were weathered in a laboratory setting, and ion chromatography was used to determine the elemental composition of the products. Divergent trends in leachate composition were observed as distance …

Design And Applications Of Fmoc-Histidine And Aspartic Acid Tripeptides As Proton Conductive Materials, Shejla S. Pollozi

Dissertations, Theses, and Capstone Projects

The increasing demand for clean and sustainable energy has driven forward rapid improvements in polymer-electrolyte fuel cells and the use of ion-conducting polymers (ionomers) as proton exchange membranes and catalyst binders. While perfluorinated electrolytes have been commercially used as conductive membranes for nearly four decades, a new class of sustainable, conductive materials has emerged, inspired by the efficiency of charge transport processes in biological systems. These molecules, knows as peptide amphiphiles (PAs), have gained popularity as building blocks for the bottom-up fabrication of nanomaterials through supramolecular self-assembly. Supramolecular nanostructures, often in the form of hydrogels, are held together via non-covalent …

Nanoscale Imaging Of Electrocatalytic Nanomaterials By High-Resolution Scanning Electrochemical Microscopy, Xiang Wang

Dissertations, Theses, and Capstone Projects

Numerous insights of the structure–electrochemical activity relationship of nanocatalysts have been obtained by using macroscopic electrochemical measurements over the last several decades. However, signals measured by large electrodes are inevitably averaged out of many nanocatalysts, non-uniformed sizes, uneven morphologies, and multiple crystallographic facets. Over the last ten years, Scanning Electrochemical Microscopy (SECM) has advanced electrochemical measurements toward micro- to nanoscale level at a high spatial resolution. The advantages of using nanoelectrode in SECM include fast mass transfer of reactive species, dominated radial diffusion pattern, small double layer capacitance and small RC constant. In this thesis, high-resolution SECM is applied to …

Ultra-Fast Bioorthogonal Spin-Labeling And Distance Measurements In Mammalian Cells Using Small, Genetically Encoded Tetrazine Amino Acids, Subhashis Jana, Eric G. B. Evans, Hyo Sang Jang, Shuyang Zhang, Hui Zhang, Andrzej Rajca, Sharona E. Gordon, William N. Zagotta, Stefan Stoll, Ryan A. Mehl

Department of Chemistry: Faculty Publications

Studying protein structures and dynamics directly in the cellular environments in which they function is essential to fully understand the molecular mechanisms underlying cellular processes. Site-directed spin-labeling (SDSL)—in combination with double electron–electron resonance (DEER) spectroscopy—has emerged as a powerful technique for determining both the structural states and the conformational equilibria of biomacromolecules. In-cell DEER spectroscopy on proteins in mammalian cells has thus far not been possible due to the notable challenges of spin-labeling in live cells. In-cell SDSL requires exquisite biorthogonality, high labeling reaction rates and low background signal from unreacted residual spin label. While the bioorthogonal reaction must be …

Data Set For "Atmospheric Aging Of Combustion-Derived Particles: Impact On Stable Free Radical Concentration And Its Ability To Produce Reactive Oxygen Species In Aqueous Media", Brian Majestic, Heather L. Runberg

Chemistry and Biochemistry: Data Sets

Environmentally persistent free radicals (EPFR) are an emerging pollutant found in soot particles. Understanding how these change as they move through the atmosphere is important to human health. Here, soot was generated in the laboratory and exposed to simulated sunlight. The concentrations and characteristics of EPFR in the soot was recorded. Additionally, formation of hydroxyl radical from the photoactivated soot was measured.

Electronic Transport Properties Of Spin-Crossover Polymer Plus Polyaniline Composites With Fe3O4 Nanoparticles, Esha Mishra, Waikiat Chin, Kayleigh A. Mcelveen, Thilini K. Ekanayaka, M. Zaid Zaz, Gauthami Viswan, Ruthi Zielinski, Alpha T. N'Diaye, David Shapiro, Rebecca Lai, Robert Streubel, Peter A. Dowben

Department of Chemistry: Faculty Publications

Adding Fe₃O₄ nanoparticles to composites of [Fe(Htrz)₂(trz)](BF₄) spin-crossover polymer and polyaniline (PANI) drives a phase separation of both and restores the molecular structure and cooperative effects of the spin-crossover polymer without compromising the increased conductivity gained through the addition of PANI. We observe an increased on-off ratio for the DC conductivity owing to an enlarged off state resistivity and a 20 times larger AC conductivity of the on state compared with DC values. The Fe₃O₄ nanoparticles, primarily confined to the [Fe(Htrz)₂(trz)](BF₄) phase, are ferromagnetically coupled to …

Progress In 7sk Ribonucleoprotein Structural Biology, Momodou B. Camara, Amr M. Sobeh, Catherine D. Eichhorn

Department of Chemistry: Faculty Publications

The 7SK ribonucleoprotein (RNP) is a dynamic and multifunctional regulator of RNA Polymerase II (RNAPII) transcription in metazoa. Comprised of the noncoding 7SK RNA, core proteins, and numerous accessory proteins, the most wellknown 7SK RNP function is the sequestration and inactivation of the positive transcription elongation factor b (P-TEFb). More recently, 7SK RNP has been shown to regulate RNAPII transcription through P-TEFb-independent pathways. Due to its fundamental role in cellular function, dysregulation has been linked with human diseases including cancers, heart disease, developmental disorders, and viral infection. Significant advances in 7SK RNP structural biology have improved our understanding of 7SK …

Exploring The Complementarity Of Measures Of Instructional Practices, Lu Shi, Robert M. Erdmann, Anthony Pellegrini, Victoria Johnson, Binh Le, Trina Popple, Zachary Nelson, Molly Undersander Gaston, Marilyne Stains

Department of Chemistry: Faculty Publications

The assessment of instructional quality has been and continues to be a desirable, yet difficult endeavor in higher education. The development of new teaching evaluation frameworks along with instruments to measure various aspects of teaching practices holds promise. The challenge rests in the implementation of these frameworks and measures in authentic settings. Part of this challenge is for instructors, researchers, and administrators to parse through and select a meaningful set of tools from the plethora of existing instruments. In this study, we aim to start clarifying the landscape of measures of instructional practice by exploring the complementarity of two existing …

Interpretation Of The Tandem Mass Spectrum Of The Novel Psychoactive Substance 5f-App-Pinaca, Px-2, Christopher S. Poulos

Graduate Theses, Dissertations, and Problem Reports (ETD)

Designer drugs and novel psychoactive substances (NPSs) are continuously entering the black market and causing serious health problems among users. NPSs present an especially difficult challenge to forensic chemists and toxicologists because they are not well characterized and often involve families of structurally related analogs. In crime laboratories, mass spectrometry is commonly used as a part of an analytical scheme to characterize and identify unknown analytes. Towards this end, tandem mass spectra of questioned analytes are often compared to reference spectra of standards that are either collected contemporaneously with the analyte or collected previously and stored in a database. However, …

Enhancing The Forensic Comparison Process Of Common Trace Materials Through The Development Of Practical And Systematic Methods, Meghan Nicole Prusinowski

Graduate Theses, Dissertations, and Problem Reports (ETD)

An ongoing advancement in forensic trace evidence has driven the development of new and objective methods for comparing various materials. While many standard guides have been published for use in trace laboratories, different areas require a more comprehensive understanding of error rates and an urgent need for harmonizing methods of examination and interpretation. Two critical areas are the forensic examination of physical fits and the comparison of spectral data, which depend highly on the examiner’s judgment.

The long-term goal of this study is to advance and modernize the comparative process of physical fit examinations and spectral interpretation. This goal is …