Chemistry Commons^™

Fundamental Study Of Dopant Effect And Toxicity In Perovskite Materials, Xun Li

Graduate Research Theses & Dissertations

This dissertation comprehensively studies the research on organic-inorganic hybrid perovskite to solve the toxicity issue of perovskite-based solar cells under practical conditions, understand the doping effect on hybrid perovskite materials in optoelectronic applications, and improve the photovoltaic performance of perovskite-based solar cells by composition tailoring. Specifically, an innovative and simple chemical approach was invented for on-device sequestration of toxic Pb leakage caused by severe device damage. To mimic the practical conditions, the sequestration of lead leakage was conducted under cold water, warm water, acid water, dripping water, and water with competitive ions. Crucially, it was found that at least 96% …

The Design And Synthesis Of New Organic Dithiols For Environmental Applications, Shashika Nadishani Bandara

Theses and Dissertations--Chemistry

A thiol molecule, 2,6-pyridinediamidoethanethiol (PB9), was synthesized based on the pyridine-2,6-dicarboxamide scaffold with appended cysteamine groups. PB9 acts as an effective chelator for Pb(II) due to multiple binding sites (N₃S₂) through irreversible binding precipitating Pb(II). Removal of aqueous Pb(II) from solution was demonstrated by exploring the effects of time, initial PB9:Pb(II) ratios, pH, exposure time, and solution temperature. After 15 min the Pb(II) concentrations were reduced from 50.00 ppm to 0.30 ppm (99.4%) and 0.25 ppm (99.5%) for PB9:Pb ratios of 1:1 and 2:1, respectively. Removal of > 93% Pb(II) was observed over multiple pH values with …

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 …

Assembly Mechanism Of Early Hsp90-Cdc37-Kinase Complexes, Dimitra Keramisanou, M.V. Vasantha Kumar, Nicole Boose, Rinat R. Abzalimov, Ioannis Gelis

Advanced Science Research Center

Molecular chaperones have an essential role for the maintenance of a balanced protein homeostasis. Here, we investigate how protein kinases are recruited and loaded to the Hsp90-Cdc37 complex, the first step during Hsp90-mediated chaperoning that leads to enhanced client kinase stability and activation. We show that conformational dynamics of all partners is a critical feature of the underlying loading mechanism. The kinome co-chaperone Cdc37 exists primarily in a dynamic extended conformation but samples a low-populated, well-defined compact structure. Exchange between these two states is maintained in an assembled Hsp90-Cdc37 complex and is necessary for substrate loading. Breathing motions at the …

Genomic Analysis Of Pollen Grains For Forensic Applications, Luz Kelley

Electronic Theses and Dissertations, 2020-2023

With over 300,000 plant species on the planet and more than 90% of them relying on pollen for reproduction, palynology, the study of pollen grains plays a vital role in many research fields. One of them is forensic palynology, which uses pollen as a proxy to link individuals or objects to a location or instance. It relies on the fact that (1) pollen is an ever-present feature of the environment; (2) different locations have different pollen signatures, allowing for inference related to spatial tracking; (3) plants bloom at different times, allowing for temporal inference; and (4) pollen is exceptionally durable …

Density Functional Theory Of Samarium(Ii) Reactivity In Thf And Water, Parisa Fasihianifard

Dissertations and Theses

Sm(II) diiodide is widely used in organic synthesis for the reduction of functional groups such as esters, anhydrides, amides, carbonyls, and arenes. Moreover, in aqueous systems and in mixtures of water and THF, the addition of Sm(II) diiodide can reduce water directly resulting in the formation of hydrogen gas. However, the mechanism of these reactions is not completely understood, making it difficult to improve experimental design. The reaction can proceed either through subsequent electron-transfer proton-transfer (ET-PT), subsequent proton transfer electron-transfer (PT-ET), or via proton coupled electron transfer (PCET). Density functional theory (DFT) calculations were performed to understand the speciation of …

Computational Study On The Nucleation Of Polyoxovanadate-Alkoxide Clusters, S M Gulam Rabbani

Dissertations and Theses

Polyoxovanadate-alkoxide (POV-alkoxide) clusters are a new class of electroactive species with potential electrochemical applications in redox catalysis, energy storage, and optoelectronics. These clusters' redox properties can be tuned by the functionalization via heterometallic installation and changing alkoxide ligands. However, the formation mechanism of these POV-alkoxides in the solvothermal process is unknown, limiting the rational design to improve their electronic properties. This dissertation reports the speciation study of POV-alkoxide clusters, which is fundamental to controlling and manipulating the evolution of transient species during their nucleation and tuning the final product's properties. Chapter 2 and chapter 3 describe our computational study of …

Semiconducting Polymer Dots-Based Ratiometric Fluorescent Probes For Detection Of Biomarkers, Shuyi He

Dissertations and Theses

Biomarkers serve a key role in illness diagnosis and treatment. Importantly, early detection can boost the therapy success rate greatly. However, traditional approaches to detect biomarkers based on fluorescence intensity changes of individual fluorophores did not completely realize the potential due to several technical problems such as low sensitivity. Ratiometric fluorescent methods use changes in the intensity of two or more emission bands (caused by the analyte) to create an internal reference that improves detection sensitivity. Due to their unique photophysical properties, such as high fluorescence intensity, high quantum yield, and low toxicity, semiconductor quantum dots (Pdots) are an ideal …

Synthesis And Characterization Of Ruthenium Complexes And Their Potential And Photosensitizers For Photodynamic Therapy, Keit Dine

Master's Theses

Cancer is one of the leading causes of death in the world with over 10 million people dying of the disease every year. Inorganic complexes supported by platinum metal centers are often used in cancer treatment. However, these complexes lack selectivity for tumor cells. As such, other alternatives to platinum have been explored. Ruthenium (Ru) complexes are one of the most promising candidates due to their ability to be used as photosensitizing drugs in photodynamic therapy. Herein, we report the design, synthesis, and characterization of two novel ruthenium-based complexes. One compound is a Ru(II) homoleptic complex, while the other is …

Gas-Phase Acid-Base Properties And Conformations Of Oligopeptides Through Mass Spectrometry And Computational Studies, Yuntao Zhang

University of the Pacific Theses and Dissertations

This dissertation presents a comprehensive study of the peptides of interest to deeper understand the gas-phase acid-base properties in relation to their conformations and chirality. In the first part of the study, two pairs of alanine (A)-based isomeric peptides consisting of a basic probe, lysine (Lys) or 2,3-diaminopropionic acid (Dap), were investigated to understand the nature of the enhanced basicity when the basic probe was moved from the N-terminus to the C-terminus. In the second part of the study, alanine-based peptides containing a cysteine (C) as the acidic probe were investigated to understand the chirality effects on the gas-phase acidity …

Investigation Of Intramolecular And Intermolecular Aza-Michael Reactions, Nadia Z. Singleton

College of Graduate Studies: Theses & Dissertations

The hydroamination of dimaleimides with diamines has been accomplished to access novel polymers. Various dimaleamides and dimaleimides were synthesized from commercially available diamines and maleic anhydride. The resulting dimaleamides were then ring-closed to their respective dimaleimides either directly in the presence of acid or via the synthesis of mixed amide-esters which then ring close in the presence of acid under heat. Hydroamination of the dimaleimides with piperazine was accomplished in bulk at room temperature. The reaction is spontaneous thus leading to the formation of polyimides with high functional group conversion within minutes. The kinetics of the maleamides and maleimides was …

Tandem Addition/Fragmentation Reactions Of Vinylogous Acyl Sulfonates, Kristen S. Nerbecki

Graduate Theses, Dissertations, and Problem Reports (ETD)

Fragmentation methodology has been used in organic synthesis to produce complex organic compounds. This work is focused on fragmentation reactions leading to the subsequent construction of neopentylene-fused carbocycles, which are found in several important natural products and are difficult to prepare. These are produced by utilizing an optimized fragmentation methodology from the Dudley group. The methodologies build starting materials called nonaflates and triflates with a gem-dimethyl substituent that is seen in many natural products. Nonaflates and triflates are similar in structure, but nonaflates pose benefits that are an advantage over triflates, like cost effective synthesis and more stable compounds. A …

Capillary Electrophoresis: Method Development And Application In Biomolecule Analysis, Lindsay Marie Veltri

Graduate Theses, Dissertations, and Problem Reports (ETD)

Abstract

Capillary Electrophoresis: Method Development and Application in Biomolecule Analysis

Lindsay Veltri

Biomolecule analysis is essential in disease diagnostics and the development of therapeutic agents. There is a vast array of methods available for biomolecule analysis, however, capillary electrophoresis is well-suited due to minimal sample consumption (~nanoliters of solution) and fast analysis times. In this report, capillary electrophoresis was used to analyze glycosylation of therapeutic proteins. Additionally, a capillary electrophoresis-mass spectrometry method is reported for the analysis of proteins.

Post-translation protein modifications like glycosylation, play an important in protein structure and function. Modifications of protein glycosylation can lead to improved …

Modeling, Fabrication, And Characterization Of Rf-Based Passive Wireless Sensors Composed Of Refractory Semiconducting Ceramics For High Temperature Applications, Kavin Sivaneri Varadharajan Idhaiam

Graduate Theses, Dissertations, and Problem Reports (ETD)

Real-time health monitoring of high temperature systems (>500^oC) in harsh environments is necessary to prevent catastrophic events caused by structural failures, varying pressure, and chemical reactions. Conventional solid-state temperature sensors such as resistance temperature detectors (RTDs) and thermocouples are restricted by their operating environments, sensor dimensions and often require external power sources for their operation. The current work presents the research and development of RF-based passive wireless sensing technology targeting high temperatures and harsh environmental conditions. Passive wireless devices are generally classified as near-field and far-field devices based on the interrogation distance. Near-field sensors are placed at …

Advancing Compound Detection And Identification Using Vibrating Sharp-Edge Spray Ionization, Anthony Paul Debastiani

Graduate Theses, Dissertations, and Problem Reports (ETD)

Advancing Compound Detection and Identification Using Vibrating Sharp-Edge Spray Ionization

Anthony Paul DeBastiani

‘Omics consists of various areas, including genomics, proteomics, lipidomics, and metabolomics with a goal of detection and identification of biomolecules present within each of these classes within an organism. Current omic analytical methods include the use of mass spectrometry (MS) coupled with various separation techniques, including liquid chromatography (LC), with the use of heated nebulization gas assisted electrospray ionization (HESI). Although the rapid progress in LC-MS platform development has lead to significant enhancements in omic studies, significant limitations in the detection and identification of low abundant species …

Synthesis And Cyclotrimerization Of Sulfonyl Enynes, Alexa C. Martin

Graduate Theses, Dissertations, and Problem Reports (ETD)

The synthesis of complex, polysubstituted aromatic rings from simple, non-aromatic building blocks is a consistent challenge to the synthetic community. Neopentylene ring fusions are found in several natural products but are largely absent from synthetic compound libraries. This discrepancy reflects the limitations in modern chemical synthesis. Utilizing, in part, a thoroughly developed fragmentation/olefination methodology from the Dudley Lab, a library of novel 1-sulfonyl-1,6-enynes have been developed. In this methodology, they are prepared in three steps from dimedone (5,5-dimethyl-1,3-cyclohexanedione), an inexpensive starting material. A total of 14 novel 1-sulfonyl-1,6-enynes were synthesized. These substrates were subjected to a novel benzannulation reaction based …

Multifunctional Organoboron Compounds And Boralactonate Salts, Randika T. Abeysinghe

Graduate Theses, Dissertations, and Problem Reports (ETD)

Organoboron compounds have gathered an important significance within the chemistry community on account of their wide range of applications in synthesis, catalysis, and medicinal chemistry. Even though the uses of boron compounds in drug discovery have been overlooked until the last several decades, boronic acid containing molecules have garnered increased attention due to the unique chemical properties of the boron center. Boron-functionalized ��-aryl propionic acid non-steroidal anti-inflammatory drug derivatives (bora-NSAIDs) can be accessed via copper(I)-catalyzed alkene boracarboxylation, using CO2 and B2pin2. To explore and expand the current synthetic and future medicinal chemistry applications of these bora-NSAIDs, methods …

Stratospheric Aerosol Composition Observed By The Atmospheric Chemistry Experiment Following The 2019 Raikoke Eruption, Chris D. Boone, Peter F. Bernath, Keith Labelle, Jeff Crouse

Chemistry & Biochemistry Faculty Publications

Infrared aerosol spectra derived from Atmospheric Chemistry Experiment measurements following the June 2019 Raikoke volcanic eruption are used to evaluate the composition of stratospheric aerosols in the Arctic. A blanket of aerosols, spanning an altitude range from the tropopause (8–11 km) to 20 km, persisted in the stratosphere over northern latitudes for many months. The aerosols within this blanket were almost exclusively sulfates. The percentage of sulfuric acid in the aerosols decreased over time, dropping below 50% H₂SO₄ concentration at some altitudes by March 2020. Contrary to previous reports, the aerosol blanket was not comprised of smoke …

Synthesis And Process Optimization Of Colloidal Unimolecular Polymer, Cup, Particle Formation, And Its Interfacial Surface Tension Behavior, Ashish Zore

Doctoral Dissertations

"Colloidal Unimolecular Polymer (CUP) particles are 3-9 nm size single-chain polymer nanoparticles that are made from amphiphilic acrylic co-polymers using the process of water reduction. The formation of CUP particles was driven by the polymer-polymer interactions being greater than polymer-solvent interactions as well as the charge-charge repulsion due to the increasing dielectric of the medium. CUPs provide a surfactant or additive-free nanoparticle system that was useful for studying the interfacial behavior of pure aqueous nanoparticles using a maximum bubble pressure tensiometer. The equilibrium surface tension shows a dependence on concentration and the charge density of the CUP particle. The equilibrium …

Synthesis, Characterization And Chemistry Of Two-Dimensional Transition Metal Carbides And Nitrides (Mxenes), Shuohan Huang

Doctoral Dissertations

"MXenes represent a relatively new and quickly growing family of two-dimensional (2D) early transition-metal carbides and nitrides first synthesized in 2011 from bulk layered crystalline MAX phases. Because of their 2D structure and unique combination of high conductivity and hydrophilicity, MXenes have raised a significant interest for various applications. However, it has been found that in some cases colloidal MXene flakes are not stable and can spontaneously degrade on a time scale from hours to days. In this work, we investigate the crucial factors for MXene degradation and demonstrate gas analysis as a powerful method to gain further insights into …

Establishing Pteridine Metabolism In A Breast Cancer Cell Model And Quantification Of Silver Nanoparticle Interactions With Yeast Cells Using Mass Spectrometry, Lindsey Katherine Rasmussen

Doctoral Dissertations

"Recent advances in analytical methods have furthered the quantitative insights that can be gleaned from cellular analyses, with applications in cancer and nanoparticle research. In the first part of the research presented, a recently developed HPLC-MS/MS method was advanced to elucidate pteridine metabolism in an isogenic progressive MCF10A breast cancer cell model. The folate-derived pteridine pathway in breast cells was established by individually dosing cell cultures with folic acid and 15 pteridines. Eight potential pteridine biomarkers in breast cancer cells were identified including pterin and isoxanthopterin, which yielded the first in vitro evidence for the cellular metabolisms behind previously reported …

Electrocatalytic Processes For Energy Storage & Conversion, Apurv Saxena

Doctoral Dissertations

"The continuous excessive usage of fossil fuels has resulted in its fast depletion leading to an escalating energy crisis as well as several environmental issues leading to increased research towards sustainable energy conversion. Electrocatalysts play crucial role in the development of numerous novel energy conversion devices including fuel cells and solar fuel generators.

High-efficiency and cost-effective catalysts are required for large-scale implementation of these new devices. Over the last few years transition metal chalcogenides have emerged as highly efficient electrocatalysts for several electrochemical devices such as water splitting, carbon dioxide electroreduction and, solar energy converters. These transition metal chalcogenides exhibit …

Design And Synthesis Of Purine Based Neuroprotectors And Novel Synthetic Methods For The Trifluoromethylation Of Aldehyde Hydrazones, Puspa Aryal

Doctoral Dissertations

"Purine-derived compounds are widely investigated as cyclin-dependent kinase inhibitors that have broad applications in the design of pharmaceuticals for treating diseases, such as diabetes, atherosclerosis, and cancers. Towards the goal of effective AGE-inhibitors, and neuroprotector compounds we have synthesized a series of novel purine-based triazoles and investigated their neuroprotective effects, using SHSY-3Y human neuroblastoma cell line. Through these studies, we have identified purine-based neuroprotector compounds that favorably modulate oxidative stress induced by the Fenton reaction-generated reactive oxygen species (ROS).

The C(sp²−H)-trifluoromethylation of hydrazones would give access to the αtrifluoromethylated hydrazones that can serve as intermediates in the synthesis …

S-Type Stars: Lao Line List For The B²Σ⁺-X²Σ⁺ Band System, P. F. Bernath, Randika Dodangodage, J. Liévin

Chemistry & Biochemistry Faculty Publications

LaO bands are a characteristic feature in the spectrum of cool S-type stars. La is made primarily by the s-process during the asymptotic giant branch phase of stellar evolution. The B²Σ⁺–X²Σ⁺ and A²Π–X²Σ⁺ band systems can be used to determine the La abundances in cool S stars. The bands of the B²Σ+–X²Σ⁺ with v' and v" ⩽ 5 have been rotationally analyzed from an emission spectrum from a carbon furnace. Line strengths are calculated using an ab initio transition dipole …

Heterogeneous Oxidation Of Multi-Component Aqueous Organic Aerosols: The Effect Of Transport Phenomena And Reaction Compartment On Reaction Kinetics., Tadini Wenyika Masaya

Graduate Theses, Dissertations, and Problem Reports (ETD)

The surface-bulk partitioning of small organic molecules in aqueous droplets was investigated using molecular dynamics. The air-particle interface was modeled using a 80-Å cubic water box containing series of organic molecules and surrounded by gaseous OH radicals. The properties of the organic solutes within the interface and the water-bulk were examined at a molecular-level using density profiles and radial pair distribution functions. Molecules containing only polar functional groups such as urea and glucose are found predominantly in the water bulk, forming an exclusion layer near the water surface. Substitution of a single polar group by an alkyl group in sugars …

Electronic Structure Of Early Transition Metal Complexes Supported By Pyridine Polypyrrolide Ligands, Dylan Connor Leary

Graduate Theses, Dissertations, and Problem Reports (ETD)

A thorough study of photoluminescent molecules involving the pyridine polypyrrole(ide) ligand platform has been conducted. A detailed analysis on speciation of the proligand H₂(^MesPDP^Ph) (H₂^MesPDP^Ph = 2,6-bis(5-mesityl-3-phenyl-1H-pyrrol-2-yl)-pyridine) and its dilithium salt Li₂(^MesPDP^Ph) revealed temperature- and solvent-dependent effects. These molecules, along with the hydrochloric acid adduct [H₃(^MesPDP^Ph)]Cl were found to exhibit short-lived photoluminescence in both tetrahydrofuran and benzene solution. These findings confirm the hypothesis that heavy-atom involvement is crucial for the favorable photophysical properties observed for the Zr(PDP)_{2 …}

Characterizing The Effects Of Solvent And Analyte Properties On Ionization Efficiency By Novel Field-Free And Field-Enabled Ionization Techniques, Kinkini Udara Jayasundara

Graduate Theses, Dissertations, and Problem Reports (ETD)

In recent years the mass spectrometry (MS) area of field and/or direct analysis has grown dramatically. As a result, field-portable and miniaturized mass spectrometers, introduced only a few years ago, are proliferating. A highly desired feature for field-portable MS, or in-field analysis, is the ability to use ionization techniques requiring very little sample preparation as well as an ability to generate the ions under ambient conditions. Recently, a new ambient ionization technique termed vibrating sharp-edge spray ionization (VSSI) has been introduced which overcomes the field-portable limitations of other spray-based methods including the requirements for auxiliary components (e.g., nebulizing gas and …

Synthesis Of Functionalized Aromatic Heterocyclic Compounds And Its Applications In Organized Self-Assemblies, Emmanuel T. Fasusi

College of Graduate Studies: Theses & Dissertations

1,2,3-triazoles due to their structure, possess good optical properties and are capable of molecular recognition by their supramolecular capabilities of utilizing weak forces of interaction (such as hydrogen bonding, dipole interaction) in establishing a close association with targets. They are easy to synthesize, which opened the opportunity for a wide pharmaceutical application, mostly as pharmacological scaffolds. However, challenges such as poor water solubility, inefficient drug delivery and increased toxicities due to frequent dosing of drugs are commonly faced which reduces the efficacy of the drugs. It is therefore important to have “delivery vehicles” which could help transport the drugs to …

Role Of Imine Isomerization In The Stereocontrol Of The Staudinger Reaction Between Ketenes And Imines, Fernando P. Cossío, Abel De Cózar, Miguel A. Sierra, Luis Casarrubios, Jaime G. Muntaner, Bimal K. Banik, Debasish Bandyopadhyay

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Chemistry)

Computational–experimental analysis has allowed determining that the stereochemistry of the Staudinger reaction between ketenes and imines is strongly associated with the nature of the imine, which affects the two steps of the reaction. The first step, namely the nucleophilic attack of the sp2-hybridized nitrogen atom of the imine on the sp-hybridized carbon atom of the ketene, is affected by the energetically accessible in situ isomerization patterns of the imine. The second step consists of a conrotatory electrocyclization of the zwitterionic intermediate formed in the previous step. This latter pericyclic step depends on the inward/outward torquoelectronic effects generated by the substituents …

Extensive Thiol Profiling For Assessment Of Intracellular Redox Status In Cultured Cells By Hplc-Ms/Ms, Jiandong Wu, Anna Chernatynskaya, Annalise Pfaff, Huari Kou, Nan Cen, Nuran Ercal, Honglan Shi

Computer Science Faculty Research & Creative Works

Oxidative stress may contribute to the pathology of many diseases, and endogenous thiols, especially glutathione (GSH) and its metabolites, play essential roles in the maintenance of normal redox status. Understanding how these metabolites change in response to oxidative insult can provide key insights into potential methods of prevention and treatment. Most existing methodologies focus only on the GSH/GSH disulfide (GSSG) redox couple, but GSH regulation is highly complex and depends on several pathways with multiple redox-active sulfur-containing species. In order to more fully characterize thiol redox status in response to oxidative insult, a high-performance liquid chromatography with tandem mass spectrometry …