Chemistry Commons^™

Synthesis And Characterization Of Sustainable And Biobased Copolymers From Lignocellulosic, Guery Saenz

Theses and Dissertations

Natural compounds have been the primary resource used to produce polymeric materials by humankind since the mid-1900s. Yet, progress in bio-based polymers from renewable feedstock has encountered some obstacles, mainly due to the low prices of petroleum-based monomers, compared to natural and sustainable materials. However, most commodity plastics are non-degradable materials, and solid plastic waste accumulation adversely affects the environment. As the world population is growing and demanding chemicals, energy, and plastics materials, polymer research is focusing on synthesizing bio-based and degradable polymers. Thus, biomass, a sustainable and inexpensive feedstock, is highly appropriate for designing alternative thermoplastics that are degradable …

The Effects Of An R103q Mutation On The Chemical And Physical Properties Of The Enzyme Cytochrome C Nitrite Reductase (Ccnir), Shahama Alam

Theses and Dissertations

Cytochrome c Nitrite Reductase (ccNiR) is a periplasmic homodimeric decaheme enzyme that catalyzes the reduction of nitrite to ammonium in a process that involves six electrons and eight protons. The project described herein explored the properties of the Shewanella oneidensis R103Q ccNiR variant and compared them to the properties of the wild type enzyme. Under standard assay conditions, which use the strong reducing agent methyl viologen monocation radical (MVred) as an electron source, the R103Q variant still catalyzes reduction of nitrite to ammonium, albeit with an MVred turnover rate that is 20% of the wild type’s (780 ± 50 s-1 …

The Activity Of Qh Ii 66 And It’S Analogs In Medulloblastoma, Melanoma And Non-Small Cell Lung Cancer Cell Lines., Taukir Ahmed

Theses and Dissertations

GABAARs (gamma-aminobutyric acid type A receptors) are transmembrane pentameric ligand-gated chloride ion channels that respond to GABA, the central nervous system's principal inhibitory neurotransmitter (CNS). The benzodiazepines (BZDs) bind between the GABAAR α+γ2-subunits at their extracellular interface. The binding of ligands to distinct subunits of GABAA receptors, notably the α1-6β2/3γ2 ion channels, can have a wide range of effects on brain activities. The sedative, ataxic, amnesic, anticonvulsant, and addictive actions of GABAARs' α1-subtype selective ion channels should be avoided, except for the anticonvulsant and anxiolytic effects, while creating ligands for this BZ allosteric modulatory site. Many studies have linked the …

In Vitro And In Vivo Identification And Quantification Of Carmofur And 5-Fluorouracil Using Tandem Mass Spectrometry, Mohammad Mohiminul Islam

Theses and Dissertations

Glioblastoma is the most aggressive solid tumor of the brain. Prior studies from our lab found that carmofur, also known as 1-hexylcarbanoyl 5-fluorouracil (HCFU) is a promising candidate in suppressing and killing tumor cell lines compared to the FDA-approved drug temozolomide. Originally developed as pro-drug of 5-fluorouracil (5-FU), carmofur has been in use in clinic for the treatment of colorectal cancer for over four decades in Japan. Having it used in clinics, it has a high probability of repurposing for diseases with no cure such as glioblastoma. Carmofur has also been found effective against other cancers such as head and …

Study Of The Chemical Fabrication Process Of Nsom Probes And The Modification Of The Probe Surface, Muhammad Nazmul Hussain

Theses and Dissertations

Near-field scanning optical microscopy (NSOM) merges scanning probe technology with the power of high-resolution optical microscopy and provides a natural view into the nanoworld. NSOM requires tapered probes with subwavelength optical apertures and wide cone angles to efficiently channel the illumination light to the tip apex so that it can acquire optical images beyond the diffraction limit. Tapered probes with a range of cone angles can be fabricated through chemical etching of optical fibers using hydrofluoric acid (HF) by varying the etching time. Apart from their use for NSOM imaging, such optical probes can also be transformed into nanosensors by …

Physicochemical Properties, Pharmacokinetics And Biodistribution Of Arm14988, An Acid Ceramidase Inhibitor, And Its Potential As Chemotherapeutic Agent For Glioblastoma, Vilashini Rajaratnam

Theses and Dissertations

Glioblastoma (GBM) is one of the most common and detrimental forms of brain tumor. While there are few FDA-approved chemotherapeutic treatments, the overall survival is still poor leading to many studies dedicated to developing more effective treatment options. Previous studies have identified acid ceramidase (ASAH1) as a potential therapeutic target for this disease. ARN14988, an ASAH1 inhibitor, has shown to be highly cytotoxic compared to the FDA-approved chemotherapy agent, temozolomide, in GBM cell lines. This initial finding makes ARN14988 a desired candidate for further drug discovery studies. Herein, the objective of this thesis is to study the pharmacological properties of …

Design And Synthesis Of Chiral And Achiral Benzodiazepines And Imidazodiazepines As Α–Subtype Selective Gabaar Positive Modulators To Treat Schistosomiasis, Epilepsy, Asthma And Some Mental Disorders, Md Yeunus Mian

Theses and Dissertations

Part I: Design, synthesis, and biological evaluation of non-sedating anti-schistosomal agents

Schistosomiasis is a parasitic flatworm infection with only one drug therapy currently on the market, praziquantel. An old lead identified by Roche, meclonazepam (US Patent 4031078A) displayed antiparasitic efficacy but was not pursued due to dose-limiting sedation in human clinical trials (S. Afr. Med J. 1979 Apr 14;55(16):617-8, PMID: 380021). However, given the superior spectrum of activity meclonazepam displays relative to praziquantel (which is unable to cure immature parasites within the host) and advances in the understanding of benzodiazepine SAR at human GABAARs, the study of this benzodiazepine was …

Part I: Synthesis Of Quinolones For Inhibition Of The Β-Barrel Assembly Machine In Gram Negative Bacteria; Part Ii: Synthesis Of Azo Dye Sensors For Detection Of Metal Ions In Aqueous Environments, Katryna Williams

Theses and Dissertations

Part I: Antibiotic resistance in Gram-negative bacteria is a growing cause of concern worldwide. Thousands of people die from antibiotic resistant bacteria every year. The β-Barrel Assembly Machine (BAM) in Gram-negative bacteria plays a role in antibiotic resistance as its porin, BamA, can regulate which molecules enter the cell, meaning it can prevent antibiotics from entering the bacterial cell. BamA exists in an open and closed form and is only selective in its closed form. BamA opens and closes through the H-bonding of two intramolecular β-strands. It is theorized that the creation of a β-sheet mimetic, based on work done …

Control Of Irradiation Wavelength And Quantum Yield Of Photocleavable Cages, Jingxuan Ma

Theses and Dissertations

An important component of biological research is the precise regulation of biomolecules in their physiological environment. Recent advances in neuroscience, have made it possible to regulate the activity of neurotransmitters using photocleavable protecting groups (PPGs), which are also known as cages. This enables the use of light as a trigger to activate selected neurons via photo release of agonists with precise control of timing as well as synaptic site, popularly referred to as spatiotemporal control. In recent years, a variety of PPGs have been developed and applied to biomolecular cages. PPGs can be classified according to their absorption wavelengths (from …

Development Of Diagnostic Tools And Analysis Of The Density Functional Theory Zoo, Pierpaolo Morgante

Theses and Dissertations

The main goal of this dissertation is to give an overview of existing and new databases for density functional theory (DFT). It describes the procedures used to introduce A Collection of Chemistry DataBases (ACCDB) and its reduction to a smaller and statistically significant database called A Small(er) Collection of DataBase (ASCDB). Also, it presents an application of such databases in chemical education through the introduction of a notebook of twelve exercises that can easily complement a computational chemistry class. In addition, a new database of molecules having carbon-carbon long bonds (CLB18) is presented. Last, the databases are used in the …

Investigation Into The Measurement Of Student Ability: Refinements, Improvements And Enhanced Understanding Of Factors That Influence Performance, David Schreurs

Theses and Dissertations

The following series of experiments were all designed and implemented with the goal of understanding and improving undergraduate students understanding of chemistry. In order to accurately access changes in student’s chemistry understanding, the first chapter focuses on how a student’s chemistry proficiency can be most effectively measured. This includes practical recommendations for the average instructor as well as advanced methods more appropriate for researchers who require highly precise scores. With a better understanding on how to measure student proficiency, the next step was working to improve student understanding through various types of feedback following assessments. On top of establishing a …

Guest Host Chemistry Part I: The Synthesis Of Metal Selective Sensors Part Ii: The Synthesis Of Antibiotic Precursors And Intermediates, Trevor Moss Hagemann

Theses and Dissertations

Part 1: Metal Selective Sensors

The work herein describes the creation of a library of sensors for the detection of metal ions in aqueous systems. The solid support these dyes are attached to facilitates a continuous measurement of metal ion concentrations in aqueous systems. The sensors are based on an azo dye core structure wherein detection of metal ions is observed by the change in absorbance of the dye upon binding. These sensors are capable of detecting metal ions in the ppb range, specific dyes interacting with specific metal ions cause distinct spectral changes, providing substantial information. the aggregate response …

Structural Analysis Of [Ni(Dippe)] Fragment Using Computational Methods, Jennifer L. Sanchez

Theses and Dissertations

The structural analysis of the Nickel (Bisdiisopropylphospino)ethane, also known as [Ni(dippe)H]2, has been heavily studied in our group in collaboration with William D. Jones's group. A computational analysis of the [Ni(dippe)] fragment was performed to determine the structural relationship between the nickel center and its phosphine ligand, due to phosphines having both electronic and steric properties. The reactivity of the Nickel will be most dependent on the dippe ligand. A conformational search generated 244 conformers after a thorough minimization using Molecular Mechanic (MM) calculations where a thorough minimization was performed and then re-minimized using a SEED command until unique conformers …

Synthesis Of Gpr119 Interacting Drugs For Treatment Of Type Ii Diabetes, Tien M. Tran

Theses and Dissertations

Type II Diabetes is one of the leading causes of death in the United States and is categorized by high blood glucose levels, insulin deficiencies, and inhibition. Located in the pancreas and intestine, the G-Protein Receptor 119 (GPR119) was noted to have an important effect on insulin secretion. Previous studies found that when the receptor is activated, insulin secretion was upregulated which is vital for type II diabetes treatment. Compounds AR437735 and AR437948 are the proposed agonist and inverse agonist pair that will be synthesized and tested for bioactivity to the receptor. It is theorized that the different double-bonded atoms …

Total Synthesis Of Mansouramycin A, Abigail M. Zepeda

Theses and Dissertations

In 2009 bioactive compounds from marine Streptomyces species was isolated which resulted in deriving four isoquinoline-quinone alkaloids known as Mansouramycins A-D. There have been reports that there are 36 non-small cancer cells against cytotoxicity in Mansouramycins A-C in lung cancer, breast cancer, melanoma, and prostate cancer cells. Reports that have conducted total syntheses were all specific to a single compound only Mansouramycin A and D. However, in precedent methods, to obtain the derivatives with different substituents are limited when the substituents are on the fused-pyridine ring. Thus, a develop a systematic synthetic methods of isoquinoline-quinones, which are to be able …

Synthesis, Characterization And Activity Of Palladium Catalysts On The Dual Support Of Cerium And Aluminum Oxides, Jihyeon Park

Theses and Dissertations

The effects of sequence of impregnation (Pd on cerium oxides -alumina and cerium oxides on Pd-alumina) and calcination temperature (500 ℃ and 850 ℃) on the catalytic oxidation of methane under lean conditions were investigated. The catalysts were prepared by a combination of impregnation, slurry and vortexing methods. The catalysts had 4.7 wt.% Pd and 10.7 wt.% Ce based on inductively coupled plasma optical emission spectrometry (ICP-OES) analysis. The catalysts were characterized by pulse chemisorption, temperature programmed reduction (TPD), scanning transmission electron microscopy (STEM), and X-ray photoelectron spectroscopy (XPS). The activity of the catalysts for methane combustion was measured in …

Modification Of Active Sites In Catalytic Materials For Gas-Phase Heterogeneous Catalysis, Deependra Man Shakya

Theses and Dissertations

Heterogeneous catalysis remains at the core of chemical manufacturing industries with 80-90 % of chemical processes relying on the use of catalysts. Unlike homogeneous catalyst that has extremely well-defined active sites, active sites in heterogeneous catalysis are complex and show dynamic behavior under reaction conditions, and change their structures, composition, particle size. The complexity associated with these systems has made the rational design of the catalyst a difficult problem. Highly crystalline metalorganic frameworks (MOFs) as heterogeneous catalysts present the unique opportunity to systematically modify the geometries, ensemble sizes, and compositions of highly dispersed active sites due to their tailorable, and …

Metal Free Bond Activation By Carboranyl Phosphines, Gayathri B. Gange

Theses and Dissertations

In the past few decades, main group-based catalysts have attracted increasing attention as an alternative approach to overcome the most prevailing issues of transition metal catalysts such as high cost, toxicity, and low abundance. Among these main groupbased catalysts, Phosphine based compounds have shown a variety of bond activations due to the strong nucleophilicity from their congener species. To the contrary, unique electron deficient boron-based clusters have the tendency to accept two electrons reversibly due to their electron deficiency. In this study, we have synchronized the electron donor ability of the phosphine with the electron acceptor ability of the ortho …

Mechanistic Understanding Of Catalytic Processes For Sustainable Chemical Transformations, Pooja J. Ayare

Theses and Dissertations

The current field of catalysis is notably advanced in terms of both conceptual and technical innovation. There is a constant need to design new catalysts and develop catalytic processes to improve the scope, efficiency, and selectivity of various chemical transformations. It is also imperative to design catalytic systems which are effective, truly-recyclable and energy efficient for a sustainable future. This can be done through comprehensive knowledge and understanding of catalyst behavior, reaction kinetics and process designing.

For most industrial processes, the preferred catalysts are heterogeneous because these solid catalysts can be easily separated from the final product. However, they often …

Sustainable Polymers: Upcycling Poly(Vinyl Chloride) And Mimicking Low Density Polyethylene, Ian Baxter

Theses and Dissertations

In this research, increasing the sustainability of polymers was investigated through two main methods. The upcycling of poly(vinyl chloride) and the creation of polymer mimics to create degradable low-density polyethylene. In the first chapter, an overview of the sustainability issues of polymers is presented and approaches are described on how their sustainability may be increased through the upcycling of polymers or the synthesis of degradable polymers that mimic the properties of petrol-based polymers.

Chapter 2 contains the progress on the upcycling of PVC using high oleic soybean oil. Soybean oil can soften PVC making it less brittle than pure PVC. …

Tailored Nanomaterials For Advancing Fast-Charge Research, Wessel Van Den Bergh

Theses and Dissertations

The demand for fast, energy-dense storage has driven research into nanoscale intercalation materials. Nanoscale materials not only accelerate kinetics but also can modify reaction path thermodynamics, intercalant solubility, and diffusivity. Pioneering works have revealed such nanoscale changes, often without the need to separately probe each fundamental transport process. While electrodes can be designed to have one transport processes dominant, there remain opportunities to better understand energy-dense designs with multiple concomitant transport constraints. The contents herein highlight emerging an method using tailored, energy-dense nanomaterials and the process of elimination to clearly correlate architectural features to performance. For example, this method revealed …

Adsorption Of Microcystins To Sediment Affects Their Bioavailability And Remediation, Ashley Womer

Theses and Dissertations

The freshwater harmful algae Microcystis spp produces a family of toxins called microcystins1. These species of algae are known to release microcystins from their cells directly into the surrounding water2. This creates an array of human health risks depending on the fate and transport of the toxins in the water column3,4. Risk modelling and previous literature has shown that sediment is a sink for free microcystin, microcystin can be stably adsorbed to sediment for hundreds of years, and its adsorption to sediment is determined by the sediment adsorption partitioning coefficient (Kd)5,6,7. In this work it is hypothesized that the sediment …

Synthesis Of Carborane Pincer Complexes And Exploration Of The Reactivity Of Metal-Boron Bonds, Hindurangalage Don Asela Chathumal Jayaweera

Theses and Dissertations

Exploration of transition metal complexes with metal-boron bonds for the cooperative bond activation of small molecules in catalysis is one of the recent developments in novel synthetic strategies. The use of boron clusters as a modular platform for the formation of metal-boron bond has been successfully utilized by our and other groups. Carboranes are icosahedral boron-carbon molecular clusters that have gained attraction as multifunctional ligands due to their unique geometry, electronic properties, and versatility of functionalization methods. Their 3-D structure exerts a steric bulk around the exohedral substituent, either metal or non-metal center. Furthermore, due to the cluster geometry, five …

Well–Defined Donor–Acceptor Materials, Gabrielle A. Leith

Theses and Dissertations

The modularity of multivariant scaffolds such as covalent–organic frameworks (COFs) provides an unprecedented level of control in the alignment of donor (D) and acceptor (A) units, a demand that is driven by the production of optoelectronic, photonic, and spintronic devices. The foray into novel motifs bearing D-A ensembles in frameworks has been applied towards material property modulation for device performance enhancement. This dissertation presents an emerging trend in the development of D-A interfaces by highlighting recent advances probing D-A interactions in porous crystalline matrices and co-crystals, with a focus on energy transfer (ET) and charge transfer (CT) processes in pre-designed …

Photophysics And Electronic Properties Of Photochromic Metal-Organic Frameworks, Corey R. Martin

Theses and Dissertations

Modulation of materials properties through light-based illumination has the capability to expand the technology sector due to stimuli-responsive dynamic behavior that cannot be achieved in traditional materials. For example, reversibly tuning photophysical profiles of such materials allows for switching between discrete states that is a key aspect for the developing logic gates, spatially- and temporally-resolved sensors, and on-demand drug delivery systems. My efforts have focused on employment of metal-organic frameworks (MOFs) as a versatile platform for the material development which contain photochromic moieties allowing for tailoring their electronic properties. Our group has expanded this direction to include heterometallic and actinide-containing …

Transition Metal Phosphides For High Performance Electrochemical Energy Storage Devices, Amina Saleh

Theses and Dissertations

Electrochemical energy storage technologies are nowadays playing a leading role in the global effort to address the energy challenges. A lot of attention has been devoted to designing hybrid devices known as supercapatteries which combine the merits of supercapacitors (high power density) and rechargeable batteries (high energy density). Transition metal phosphides (TMP) are a rising star for supercapattery anode materials thanks to their high conductivity, metalloid characteristics, and kinetic favorability for fast electron transport. Herein, new TMP-based materials were synthesized for use as supercapattery positive electrodes, via a multifaceted approach to yield devices enjoying concurrently high power and energy densities. …

Design And Fabrication Of Nanostructured Electrodes For Complementary Electrochemical And Photoelectrochemical Water Splitting, Kholoud El Sayed Abousalem

Theses and Dissertations

Designing highly active, durable, and nonprecious electrodes for overall water splitting is of urgent scientific importance to realize sustainable hydrogen production. Accordingly, the need to search efficient energy production systems is of crucial necessity. In this thesis, two various systems for sustainable hydrogen production have been reported using electrochemical and photoelectrochemical pathways. In the first part of the thesis, electrochemical water splitting involving both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) has been established. To this end, an innovative approach is demonstrated to synthesize flower-like 3D homogenous trimetallic Mn, Ni, Co phosphide catalysts directly on nickel foam via …

Atomistic Simulation Of Na+ And Cl- Ions Binding Mechanisms To Tobermorite 14Å As A Model For Alkali Activated Cements, Ahmed Abdelkawy

Theses and Dissertations

The production of ordinary Portland cement (OPC) is responsible for ~8% of all man-made CO2 emissions. Unfortunately, due to the continuous increase in the number of construction projects, and since virtually all projects depend on hardened cement from the hydration of OPC as the main binding material, the production of OPC is not expected to decrease. Alkali-activated cement produced from the alkaline activation of byproducts of industries, such as iron and coal industries, or processed clays represents a potential substitute for OPC. However, the interaction of the reaction products of AAC with corrosive ions from the environment, such as Cl-, …

Progress Towards Next Generation Modulators Of Ctbp's Oncogenic Effects, Jacqueline L. West

Theses and Dissertations

Human C-terminal binding proteins (CtBP1 and CtBP2) are transcriptional coregulators of multiple genes in the human genome, including tumor suppressor genes (e.g., Bik, PTEN, BRCA1, and E-cadherin) as well as oncogenes (e.g. MDR1 and Tiam1). Both homologues of CtBP are overexpressed in many types of cancer, including breast cancer (92%), ovarian cancer (83%), colorectal cancer (64%), hepatocellular carcinoma (60%), gastric cancer, prostate cancer, and pancreatic adenocarcinoma. Further, expression levels of CtBP correlate with worse prognostic outcomes and more aggressive tumor features because it promotes proliferation, epithelial-mesenchymal transition, and cancer stem cell self-renewal activity.

Our laboratory has identified a lead inhibitor …

Analysis Of Microdroplets And Microorganisms By Single Entity Electrochemistry, Junaid U. Ahmed

Theses and Dissertations

Single Entity Electrochemistry (SEE) is an emerging electrochemical technique that has been used to characterize discrete entities by measuring the change in current or potential during individual stochastic events (collision or adsorption) of an entity with an ultramicroelectrode (UME) of similar dimensions. The shape and magnitude of the SEE signal depend on the underlying mechanism of interaction with the UME surface. There is a critical need for quantitative models that correlate the SEE signal with properties of the entity-UME system, including effects of acquisition instrumentation, to prevent misinterpretation of data.

This research focused on integrated experiments and simulations to quantify …