Chemistry Commons^™

Enhancing Upconversion Nanoparticle Performance Of Nayf4: Yb,Tm With Doping Optimization And Shell Addition And Of Nayf4: Yb,Er With Yb,Nd Shell Addition, Ashleigh M. Chov

Honors Thesis

Upconversion (UC), is a phenomenon that occurs when low-energy excitation (usually near-infrared (NIR)) results in higher-energy emission. Upconversion nanoparticles (UCNPs) are particles less than 100 nm in size that are synthesized using rare earth metals such as Yb, Er, Tm, and Y. UCNPs have important applications in a variety of fields, including bio-imaging, security printing, and latent fingerprint development. Traditional methods for latent fingerprint development such as fluorescent powder dusting have several drawbacks including low contrast, high background interference, and autofluorescence. NIR-to-NIR UCNPs are composed of NaYF₄: Yb, Tm and emit 800 nm light under 980 nm excitation …

Ti2ctx Mxene-Based All-Optical Modulator, Jun Yi, Jie Li, Shuohan Huang, Longyu Hu, Lili Miao, Chujun Zhao, Shuangchun Wen, Vadym Mochalin, Apparao M. Rao

Chemistry Faculty Research & Creative Works

MXenes, a new class of 2D transition metal carbides, nitrides, and carbonitrides, have attracted much attention due to their outstanding properties. Here, we report the broadband spatial self-phase modulation of Ti₂CT_x MXene nanosheets dispersed in deionized water in the visible to near-infrared regime, highlighting the broadband nonlinear optical (NLO) response of Ti₂CT_x MXene. Using ultrafast pulsed laser excitation, the nonlinear refractive index n2 and the third-order nonlinear susceptibility (Formula presented.) of Ti₂CT_x MXene were measured to be ∼10−13 m2/W and ∼ 10−10 esu, respectively. Leveraging the large optical nonlinearity of Ti …

A Cascade Reaction Of Cinnamyl Azides With Acrylates Directly Generates Tetrahydro-Pyrrolo-Pyrazole Heterocycles, Angela S. Carlson, En Chih Liu, Joseph J. Topczewski

Chemistry Faculty Research & Creative Works

Developing reactions to generate complex and modular building blocks in a concise and direct fashion remains a contemporary synthetic challenge. This work describes a stereoselective cascade reaction between allylic azides and acrylates that directly generates tetrahydro-pyrrolo-pyrazole ring systems. These products contain up to four contiguous stereocenters, two of which may be tetrasubstituted carbon atoms attached to a nitrogen atom. Over 30 examples are provided with an average isolated yield of 71% (ranging from 40% to 94%). The reaction was easily scaled to use more than one gram of starting material, and the products can be readily diversified.

Improving Biodiesel Through Pyrolysis: Direct Dynamics Investigations Into Thermal Decomposition Of Methyl Linoleate, Michael Bakker

Graduate Theses/Dissertations

Dependence on petroleum and petrochemical products is unsustainable as it is both a finite resource and environmentally hazardous. Biodiesel is a proposed alternative, but has complications including possessing poor cold weather operability and lacking the ability to supplement other petrochemical products (e.g., ethylene, hexane, etc.) relied upon in society. Pyrolysis of biodiesel has demonstrated the formation of smaller hydrocarbons comprising many of these petrochemical products. Our aim is to computationally simulate the pyrolysis of methyl linoleate, the most prevalent component in biodiesel formed in the US (from soybean). We make use of unimolecular direct dynamics describing intramolecular processes, introducing Temperature …

Thiol-Ene Click Chemistry For Solid State Triplet-Triplet Annihilation Upconversion And Parts-Per-Billion Pyrophosphate Sensing In Artificial Seawater, Abagail K. Williams

Master's Theses

Thiol-ene click chemistry is a robust approach to molecularly engineering polymers for many applications. Within this work, thiol-ene click chemistry is used to fabricate thiol-ene networks for TTA-UC and to synthesize a conjugated polyelectrolyte (CPE) used as a pyrophosphate (PPi) sensor in complex aqueous media. Chapter I focuses on the synthesis and upconversion performance of rubbery networks fabricated using thiol-ene click photopolymerization. The advancement of triplet-triplet annihilation based upconversion (TTA-UC) in emerging technologies necessitates the development of solid-state systems that are readily accessible and broadly applicable. We demonstrate that thiol-ene click chemistry can be used as a facile cure-on-demand synthetic …

Investigation On The Morphology Of Charge-Transfer Complexes In Low Density Polyethylene, Wade Korf

Master's Theses

Fillers are used ubiquitously throughout the fields of polymer and material science to overcome many inherent limitations to polymeric materials (i.e. poor stiffness or strength) and to expand their potential applications. There is a need to develop controllable particle architectures to better understand fundamental structure-property relationships in particle reinforced polymer composites. Charge-transfer complexes (CTCs) can assemble in situ into various needle and dendritic shapes via simple fabrication processes and at low loading levels. In this study, the effect of tetrathiafulvalene (TTF) and 7,7,8,8-tetracyanoquinodimethane (TCNQ) CTC crystallites of various shapes and sizes on composite mechanical properties was investigated in an LDPE …

Geochemical Tracers Of Arctic Ocean Processes: A Study Of Gallium, Barium, And Vanadium, Laura M. Whitmore

Dissertations

The Arctic Ocean is linked to the global oceans and climate through its connectivity with the North Atlantic Ocean and the regional thermohaline deep water formation sites. It’s also a region undergoing rapid environmental change. To inform the community of potential changes in geochemical and biogeochemical cycles, this dissertation addresses three dissolved geochemical tracers (gallium, barium, and vanadium) as indicators of Arctic Ocean processes. Gallium is tested as a replacement for nutrient-type tracers in an effort to deconvolve Pacific and Atlantic derived waters in the Arctic Ocean basins. These water masses carry different heat and salt content and can influence …

Hot Electron Chemistry On Bimetallic Plasmonic Nanoparticles, Bryn E. Merrill, Bingjie Zhang, Jerry Larue

Student Scholar Symposium Abstracts and Posters

Catalysis provides pathways for efficient and selective chemical reactions through the lowering of energy barriers for desired products. Gold nanoparticles (AuNP) show excellent promise as plasmonic catalysts. Localized surface plasmon resonances are oscillations of the electron bath at the surface of a nanoparticle that generate energetically intense electric fields and rapidly decay into energetically excited electrons. The excited electrons have the potential to destabilize strongly bound oxygen atoms through occupation of accessible anti-bonding orbitals. Tuning the anti-bonding orbitals to make them accessible for occupancy will be achieved by coating the AuNP in a thin layer of another transition metal, such …

Discriminating Azo Dyes: Conjugated Polymers, The Inner Filter Effect, And Array Sensors, Erin Crater

Honors Theses

Azo dyes are abundant pollutants that contaminate water supplies and threaten humans, biota, and ecosystem health. Their detection and discrimination are an incredible challenge due to the structural, chemical, and optical similarities between dyes, the complexity of the wastewater environment in which they are found, and their low environmental concentrations. In this work, the inner filter effect (IFE), combined with conjugated polymer array-based sensing, is utilized for the quantitative profiling of these pollutants. The array was constructed using three fluorescent, anionic conjugated polyelectrolytes whose varying spectroscopic properties led to distinct IFE patterns in the presence of the dyes. The unique …

Molecular Dynamics Simulations Of Apolipoprotein A1 In Ionic Liquids, Benjamin Smith

Honors Theses

High-density lipoprotein function is essential for the healthy processing of fats in the blood. The function of these proteins is determined by their conformational structure of chains of amino acids. Certain ionic liquids have been shown to interact with individual amino acids to affect the tertiary shape of the protein. These interactions can disrupt the native hydrogen bonds between amino acids which can either promote folding or denaturing of the protein. Our work focused on apoA-1, a high-density lipoprotein that binds to cholesterol for efflux from the body. We studied this protein in different ion-based liquids with sodium, chloride, and …

Gold Nanoparticles: Core Conversion Of Au144(Sch2ch2ph)60 To Au99(Sph-Ch3)42 Using Aromatic Thiolate Ligands And Crystallization Of Au99(Sph-Ch3)42, Elizabeth Turnage

Honors Theses

The purpose of this thesis is to synthesize Au₁₄₄(SCH₂CH₂Ph)₆₀ using a two-step synthesis reaction, and then using this product to conduct a core conversion from Au₁₄₄(SCH₂CH₂Ph)₆₀ to Au₉₉(SPh-CH₃)₄₂. The Au₉₉(SPh-CH₃)₄₂ product will then be used to attempt to form crystals using five different crystal set-up methods. Au₁₄₄(SCH₂CH₂Ph)₆₀ is made with aliphatic thiolate ligands, and when it is placed in a mixture containing excess para-methyl benzenethiol, it undergoes a …

Raman Spectroscopic And Quantum Chemical Investigation Of The Effects Of Tri-Methylamine N-Oxide (Tmao) On Hydrated Urea, Hydrated Guanidinium, And Hydrogen Bonded Networks, Genevieve Verville

Honors Theses

Trimethylamine N-Oxide (TMAO), guanidinium, and urea are three important

osmolytes with their main significance to the biophysical field being in how they

uniquely interact with proteins. TMAO is known to stabilize and counteract the

destabilizing effects of both urea and guanidinium. The exact mechanisms by which

TMAO stabilizes and both guanidinium and urea destabilize folded proteins continue

to be debated in the literature. Some studies suggest that solvent interactions do not

play a large role in TMAO’s stabilizing effects and therefore advocate direct

stabilization, whereas others suggest that TMAO counteracts denaturation primarily

through an indirect effect of strong solvent interactions. …

Electrochemical Reduction Of Carbon Dioxide And Carbon Monoxide For The Production Of Green Fuels And Chemicals., Jacob M. Strain

Electronic Theses and Dissertations

It has become apparent that closing the carbon cycle on this planet in order to mitigate disastrous consequences of runaway global warming has become one of the most pressing issues of our civilization. One of the ways we need to accomplish this goal is by finding news methods to generate fuels that will be carbon neutral. Renewable fuels and green chemicals will be a major component of closing the carbon cycle and restoring our planet’s ecosystem into a sense of balance. A method that can help achieve this goal is the reduction of CO₂. If CO₂ can …

Computational Modeling Of Photolysis And Catalysis Reactions In Vitamin B12-Dependent Enzymes., Abdullah Al Mamun

Electronic Theses and Dissertations

Vitamin B₁₂ is a complex organometallic molecule, the derivatives of which such as adenosylcobalamin (AdoCbl) and methylcobalamin (CH₃Cbl) act as a cofactor in numerous enzymatic reactions. These two biologically active cofactors contain a unique organometallic Co-C σ bond. Important feature of this Co-C bond is that it can be activated by both thermally and photolytically inside the enzymatic environment as well as in the solution. In the case of enzymatic reactions where AdoCbl molecule act as a cofactor, the cleavage of the Co-C bond constitutes the key catalytic step. The most intriguing features of this cleavage is …

Size-Dependent Inhibitory Effects Of Antibiotic Nanocarriers On Filamentation Of E. Coli, Preeyaporn Songkiatisak, Feng Ding, Pavan Kumar Cherukuri, Xiao-Hong Nancy Xu

Chemistry & Biochemistry Faculty Publications

Multidrug membrane transporters exist in both prokaryotic and eukaryotic cells and cause multidrug resistance (MDR), which results in an urgent need for new and more effective therapeutic agents. In this study, we used three different sized antibiotic nanocarriers to study their mode of action and their size-dependent inhibitory effects against Escherichia coli (E. coli). Antibiotic nanocarriers (AgMUNH–Oflx NPs) with 8.6 × 10², 9.4 × 10³ and 6.5 × 10⁵ Oflx molecules per nanoparticle (NP) were prepared by functionalizing Ag NPs (2.4 ± 0.7, 13.0 ± 3.1 and 92.6 ± 4.4 nm) with a monolayer …

Optimizing The Synthesis Of A Theranostic Rhodamine, Alessandra Maisielou Rivera, Jonathan Alexander, Nathaniel Garrison

Creative Activity and Research Day - CARD

Current designs for small molecule theranostics, which serve both a diagnostic and therapeutic role, often involve dyes linked to therapeutic agents through a cleavable, traceless linker. In order to facilitate the separation of the dye from the therapeutic in response to a biological or chemical stimulus, linkers must incorporate elements of molecular logic, increasing their complexity and the overall bulk of the small molecule theranostic. By combining the self-immolative molecular logic of the linker into the structure of the dye itself, we hope to create a series of smaller, more atom-economical theranostics. Rhodamine dyes, which naturally possess aromatic rings with …

Determining The Impact Of Double-Layer Formation On Electrostatic Dna Melting, Gayatri Raghu

Creative Activity and Research Day - CARD

Electrostatic melting is an electrochemical tool that can be used to analyze the stability of the DNA double helix, allowing for the detection of various mutations in double stranded DNA (dsDNA).1 Here we explore the effect of electrochemical double layer formation on the electrostatic melting of dsDNA in an effort to better understand the mechanism of the aforementioned category of melting. Previous studies from our lab have shown that electrostatic melting curves can be used to distinguish between duplexes that are fully complementary and duplexes that contain a single mismatch.2 Electrostatic melting is assumed to result from the electrostatic repulsion …

Development Of Hyperpolarizable Macrocyclic 13c-Probes For The Quantification Of Metals In Vivo, Holly Clancy

Creative Activity and Research Day - CARD

Numerous studies have shown correlations between various diseases, such as cancer and Alzheimer’s disease, and a change in the concentration of metals in tissues. Current blood analysis-based methods of metal quantification do not always provide a sense of metal concentration in tissue samples. With this work, we aim to develop a non-surgical method to quantify metal concentrations in human tissue. Hexadentate ligands such as ethylenediaminetetraacetic acid (EDTA) tagged with a 13C label at the carbonyl position have shown specific shifting of the carbonyl peak upon complexation with various metals via magnetic resonance spectroscopy (MRS). Additionally, these compounds have shown increased …

Temperature-Dependence Of Electrostatic Dna Melting, Jeffrey Taylor

Creative Activity and Research Day - CARD

Electrostatic melting is a recently developed electrochemical tool that can be used to interrogate DNA stability, allowing for discrimination of double-stranded DNA (dsDNA) by base-pair sequence or the presence of mismatches, deletions, and other mutations (1). This type of analysis has potential applications in point-of-care diagnostics. Here we explore the dependence of temperature and potential on the kinetics of electrostatic melting in an effort to better understand the mechanism. Previous studies, by another group, have shown that the potential at which electrostatic melting occurs decreases with temperature in the range 10 – 18 °C, i.e. the melting becomes easier at …

Synthesis Of Sultams From Vinyl Aziridines And 1,4-Diazabicyclo[2.2.2]Octane Bis(Sulfur Dioxide), John Gandara

Creative Activity and Research Day - CARD

Sultams are an important functional group found in medicinal compounds with anticancer and enzyme inhibition activity. Traditional methods for sultam synthesis often require harsh conditions and have limited substrate scope. This research focuses on developing a novel methodology for the production of sultams using DABSO (1,4-diazabicyclo[2.2.2]octane bis(sulfur dioxide)) and vinylic aziridines. Our synthetic strategy starts with a Corey-Chaykovsky epoxidation of cinnamaldehyde, followed by an epoxide-opening using sodium azide. The final vinylic aziridine is synthesized by mesylation and Staudinger reduction of the resulting azido alcohol. Reaction of this vinyl aziridine with DABSO may provide a new strategy for synthesizing sultams. Following …

Synthesis Of Self-Immolative Rhodamine Based Theranostic Agent, Jonathan Alexander, Alessandra Rivera, Nathaniel Garrison

Creative Activity and Research Day - CARD

Theranostic agents, a class of molecules that simultaneously serve both a diagnostic and therapeutic function, enable in vivo imaging for early diagnosis and targeted drug delivery within a single entity. Due to recent advances in the synthesis and photophysical properties of the rhodamine scaffold, rhodamine dyes present a promising new direction for theranostic research. Toward the goal of exploring rhodamine dyes as self-immolative prodrugs for theranostic applications, we have synthesized a rhodamine precursor via a telescoped radical bromination/hydrolysis. Upon completion of the full rhodamine synthesis, we will explore and optimize the kinetics of its “turn-on” fluorescence and drug release in …

Determining The Mechanical Properties Of The E. Coli Methionine Transporter, Kha Andy Tran

Creative Activity and Research Day - CARD

Adenosine Triphosphate Binding Cassette (ABC) transporters constitute a superfamily of active transporters embedded in the cellular membrane. They consist of two highly conserved nucleotide-binding subunits which bind and hydrolyze ATP, and two diverse transmembrane subunits which provide a pathway for the substrate to pass through the membrane. ABC transporters serve a broad range of vital functions. Various conditions like cystic fibrosis and Stargardt disease are caused by defunct ABC transporters, and certain medical complications like antibiotic drug resistance are linked to promiscuous ABC transporters. Despite the importance of these transporters in crucial biological processes, the mechanisms of many transporters are …

Towards The Development Of Redox-Responsive Eu(Iii) Complexes For Cancer Imaging, Matthew Derfus

Creative Activity and Research Day - CARD

Cancer cells display redox dysregulation and lowered cytosolic pH as a means to maintain their over-proliferation. The development of an approach to probe tissue redox state could potentially allow discrimination between healthy and cancerous tissues. Magnetic Resonance Imaging (MRI) is a non-invasive technique used in the diagnosis of a variety of pathologies. The high spatial resolution and its use of non-ionizing radiation make MRI an attractive technique for cancer screening and detection. The quality of an MR image can be further enhanced with the aid of contrast agents, the majority of which are Gd(III) complexes. Gd(III) complexes provide positive contrast …

Investigating The Mechanism Of The E.Coli Atp-Binding Cassette Transporter Metni, Matthew Foronda

Creative Activity and Research Day - CARD

Intracellular chemical homeostasis is vital for cell survival. A key component for the maintenance of this homeostasis is ABC (ATP-binding cassette) transporters. These highly-conserved transporters utilize the energy from ATP binding and hydrolysis to move a wide array of substrates against their chemical gradient. Mutations can lead to a variety of diseases including cystic fibrosis and drug-resistant tumors. In order to solve these issues, these transporters must be well-studied. This project focuses on the mechanism of the methionine importer MetNI in E. coli, a reliable model for many transporters. Using fluorescence anisotropy, the apo-form of the substrate-binding protein (SBP) was …

Probing The Oxidation Chemistry Of Dimethoxymethane, A Model Ome Fuel, Rory Mcclish

Creative Activity and Research Day - CARD

The threat posed by anthropogenic global warming, along with attached mitigation policies, drives the search for alternative fuels or additives; this search requires understanding the combustion chemistry of possible biofuel candidates. The low-temperature oxidation of a potential diesel fuel substitute, dimethoxymethane (DMM, m/z 76), is herein investigated at 500K, 600K, and 700K using synchrotron radiation coupled with multiplexed photoionization mass spectrometry at the Advanced Light Source within the Lawrence Berkeley National Laboratory. The experimental data is resolved in 3 dimensions: time, mass, and photon energy; this allows for identification, characterization, and quantification of primary products. Energetics calculations are carried out …

Enhancement Of Phase Change Material Sorbitol By Nanoparticle Inclusion For Improving Thermal Energy Storage Capabilities, Joshua Kasitz

Mechanical Engineering Undergraduate Honors Theses

Thermal management of electronic devices has become an increasingly vital field of study with the rapid miniaturization of many key electrical components. With the significant improvement of semiconductor manufacturing and intensified focus on interconnects, electronic devices have decreased in size at an incredible rate. Decreasing spatial requirements is essential to improving device capabilities as the electronic system is able to incorporate more components. Currently, electronic systems are drastically limited by the capabilities of their cooling mechanisms. Smaller devices lead to large increases in the energy density of the system and require more powerful cooling systems to maintain proper component operating …

Recombinant Expression Of Preptin Analogs For Alanine Scanning Mutagenesis Of Residues 27-29, Tehgan N. Anguilm

Theses and Dissertations

The novel peptide preptin consists of 34 amino acid residues corresponding to Asp⁶⁹-Leu¹⁰² of proinsulin-like growth factor E-peptide. Preptin has been isolated from pancreatic beta cells, and it has been found to exhibit both metabolic and mitogenic activities. This makes preptin an attractive candidate to treat insulin-independent diabetes and osteoporosis. Alanine scanning mutagenesis was utilized to substitute an alanine for residues Trp²⁷, Arg²⁸, and Gln²⁹ of preptin in order to ultimately study the structure-activity relationship of these residues to preptin’s metabolic activity.

Identification And Quantification Of Classic, Prescription, And Synthetic Opioids In Hair By Liquid Chromatography Tandem Mass Spectrometry (Lc/Ms/Ms), Natalia A. Platosz

Student Theses

The current use and misuse of synthetic and prescription opioids in the US has reached epidemic status. According to the US Department of Health and Human Services, every day more than 130 people in the US die after overdosing on opioids, and 2.1 million had an opioid use disorder in 2016. Hair is becoming an alternative matrix of increasing interest in forensic toxicology to investigate drug use and abuse patterns due to its long window of detection. The focus of this project was to develop and validate a method that simultaneously detects and quantifies 27 classic, prescription and synthetic opioids …

Toxicity Analysis Of 2’-Deoxyguanosine-N2-6-Aminopyrene And 2’-Deoxyguanosine-N2-8-Aminopyrene In Escherichia Coli, Emily Janeiro

Honors Scholar Theses

Cancer is a disease that stems from genomic errors that are not corrected properly by cellular repair mechanisms. Errors are more likely to form when organisms are subjected to DNA damage by mutagenic compounds. 1-Nitropyrene, a nitrated polycyclic aromatic hydrocarbon (nitro-PAH), has been shown to be a potent mutagen that causes cancer. Nitro-PAHs can arise from diesel exhaust products in the environment. Out of all nitro-PAHs, 1-nitropyrene is found in largest quantities in the environment. This poses a great need to study its effects biochemically in order to address its toxicity in DNA. Other nitropyrene derivatives, including 1,6-dinitropyrene and 1,8-dinitropyrene, …

Elucidating The Binding Pockect Of The Gpr119 Receptor, A Type 2 Diabetes Target, Matthew Dy Rosales

Theses and Dissertations

An in-house homology model of the GPR119 receptor was used to identify residues which may affect ligand binding and ligand-dependent activity through computational and experimental studies. In a docking study comparing an agonist and its inverse agonist structural analog, Leu5.43169, L6.52242 and Ser1.324 appear to be involved in ligand binding. These residues were mutated experimentally to test the predictions of the homology model. The in vitro studies indicate that Leu5.43169 and Ser1.324 mutations cause ten-fold and six-fold decreases in ligand-induced cAMP formation, indicating their importance in ligand-induced activation. Leu6.52242 mutations show minimal effect in cAMP production, indicating a lesser involvement …