Chemistry Commons^™

Promoting Thermal Conductivity Of Alumina-Based Composite Materials By Systematically Incorporating Modified Graphene Oxide, Nawon Lee, Jinsol Park, Nayeon Jang, Sehui Lee, Dayeon Kim, Sanggin Yun, Tae Woo Park, Jun-Hyun Kim, Hyun-Ho Park

Faculty Publications – Chemistry

Small amounts of thermally conductive graphene oxide (GO) and modified GO are systematically introduced as a second filler to thermal interface materials (TIMs) consisting of alumina (Al2O3) particles and polydimethylsiloxane (PDMS). The surface of GO is covalently linked with an organic moiety, octadecylamine (ODA), to significantly improve the miscibility and dispersity of GO across the TIM matrix. Subsequently, two series of PDMS-Al2O3 composite TIMs are manufactured as a function of GO and ODA-GO content (0.25 wt%–2.5 wt%) to understand the effect of these second additives. The incorporation of GO into the Al2O3-PDMS composite materials generally increases the thermal conductivity (TC), …

Identifying Quantum Interference Effects From Joint Conductance–Thermopower Statistics, Justin P. Bergfield

Faculty Publications – Chemistry

Although quantum effects are thought to dominate the heat and charge transport through molecular junctions, large uncertainties in chemical structure, lead-molecule coupling strengths, and energy levels make it difficult to definitively identify these effects from the measured thermopower S and conductance G distributions alone. Here, we develop a simple statistical method to identify destructive quantum interference features (nodes) through the anticorrelation between simultaneously measured G and S values. We find these correlations can be used to unambiguously identify far-detuned nodes, even when G and S distributions alone cannot. As an example, we consider several para- and meta-configured systems, including benzenediamine …

Assessment Of Conjugation Pathways In N-Methylporphyrins That Are Fused To Acenaphthylene, Phenanthrene Or Pyrene: Evidence For The Presence Of Alternative Aromatic Circuits, Jared S. Salrin, Brian G. Carpenter, Deyaa Abusalim, Timothy D. Lash

Faculty Publications – Chemistry

Acenaphtho-, phenanthro-, and pyrenopyrrole esters, readily available from Barton-Zard reactions of ethyl isocyanoacetate with nitroarenes, were reacted with methyl iodide and KOH in DMSO to give N-methylpyrroles and subsequent cleavage of the ester moieties was accomplished with KOH in ethylene glycol at 200 °C. Condensation with two equiv of an acetoxymethylpyrrole in refluxing acetic acid-2-propanol afforded a series of annulated tripyrranes. Cleavage of the terminal tert-butyl ester groups with trifluoroacetic acid, followed by condensation with a diformylpyrrole and oxidation with FeCl3, gave N-methyl acenaphtho-, phenanthro-, and pyrenoporphyrins. The N-methyl substituent effectively freezes the tautomeric equilibria to maximize interactions between the …

Concentration Effects Of Ytterbium(Iii) Ions On The Physical, Structural, Thermal, And Optical Properties Of Barium Phosphate Glasses, Richard Amesimenu

College of Graduate Studies: Theses & Dissertations

Ytterbium(III)-doped glasses are widely known for their application in near-infrared (NIR) lasers and nowadays attract attention for solar spectral conversion in photovoltaic cells. In this study, the effects of ytterbium(III) concentration on the physical, structural, optical, and thermal characteristics of Yb-doped phosphate glasses were investigated. The glasses were synthesized using the melt-quenching technique with nominal compositions of 50P₂O₅:(50 – xBaO):xYb₂O₃ (x = 0, 0.5, 1.0, 2.0, 3.0 and 4 mol%). The properties were then examined by density and related parameters, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform-infrared …

Investigating The Ultrafast Dissociation Dynamics Of Energetic Materials Using Femtosecond Time-Resolved Mass Spectrometry, Jacob M. Shusterman

Theses and Dissertations

Shock initiation of energetic materials produces cations and anions that can contribute to initial endothermic chemical reactions which lead to detonation. Hence, knowledge of the initial dissociation pathways of ionized energetic molecules is important for advancing the understanding of initiation mechanisms and meeting longstanding goals of the Department of Defense. Despite their potential importance, these transient charged species are difficult to detect in detonation experiments and are often ignored in molecular dynamics modeling of shocked energetic materials. However, the technique of pump-probe femtosecond time-resolved mass spectrometry (FTRMS) paired with complementary theoretical calculations can be used to elucidate initial unimolecular dissociation …

Illuminating Function And Enabling Inhibition At The Protein-Membrane Interface Of Glutathione Peroxidase 4., Courtney L. Labrecque

Theses and Dissertations

Membrane proteins act as gateways to cells and are responsible not only for signaling, lipid transport, and cellular homeostasis, but they are also integral in disease pathologies. One class of membrane proteins, peripheral membrane proteins (PMPs), reside in aqueous compartments of the cell until they are recruited to the membrane to perform their function. Glutathione peroxidase 4 (GPx4) is a PMP enzyme responsible for engaging the membrane and reducing lipid hydroperoxides, thereby preventing cellular death via ferroptosis. Due to its central function surrounding ferroptosis, GPx4 is an interesting drug target that has recently gained interest for inflammatory diseases as well …

Elucidation Of The Optical Properties Of Si And Si-Ge Alloy Nanostructures With Visible To Near-Ir Photoluminescence, Griffin Spence

Theses and Dissertations

Silicon and silicon-germanium alloy nanostructures have garnered increasing attention in the past 25 years due to their favorable optical properties, visible to near-IR luminescence, and inherently low toxicity. While many synthetic routes have been discussed in the literature, the high-temperature, solid-state disproportionation of hydrogen silsesquioxane (HSQ) has become the most popular way to produce highly crystalline, size-tunable Si and Si-based nanostructures (NCs). It has been shown in this work that maximum annealing temperature from 450°-1100°C and the addition of GeI₂or SnCl₄ precursors can be used to achieve different morphologies, alloying efficiency, and sizes. Directly annealing HSQ from …

การพัฒนาจีโอพอลิเมอร์ซีเมนต์เพื่อใช้งานเป็นคอนกรีตอัดแน่นด้วยตัวเอง, ภัทรีวรรณ อิ่มสุวรรณ์

Chulalongkorn University Theses and Dissertations (Chula ETD)

ในงานวิจัยนี้เป็นการพัฒนาวิธีการเตรียมจีโอพอลิเมอร์ซีเมนต์ เพื่อใช้งานเป็นคอนกรีตอัดแน่นด้วยตัวเองโดยวิธีการเตรียมแบบจีโอพอลิเมอร์ซีเมนต์ เพื่อนำมาใช้ในงานก่อสร้างโดยใช้แนวคิดแบบเดียวกับการเตรียมปูนซีเมนต์ที่เมื่อทำการเติมน้ำลงไปผสมก็พร้อมใช้งาน ด้วยวิธีการนี้จะช่วยลดขั้นตอนและความยุ่งยากในการผสมเมื่อเทียบกับวิธีการเตรียมจีโอพอลิเมอร์แบบดั้งเดิม ในการศึกษานี้เถ้าลอยจะถูกนำมาผสมกับสารกระตุ้นด่างทั้งสามชนิด ได้แก่ โซเดียมเมต้าซิลิเกต แคลเซียมไฮดรอกไซด์ และโซเดียมไฮดรอกไซด์ ในอัตราส่วนต่างๆ ดังนี้ 49:49:2, 47.5:47.5:5, 46:46:8 และ 45:45:10 ส่วนผสมเหล่านี้ถูกนำไปบดด้วยลูกบดในช่วงเวลาที่แตกต่างกัน คือ 0, 6, 12 และ 24 ชั่วโมง จะได้ออกมาเป็นจีโอพอลิเมอร์ซีเมนต์ชนิดผง สารลดน้ำพิเศษในกลุ่มพอลิคาร์บอกซิเลตอีเทอร์จะถูกเติมลงไปปริมาณ 2% ของน้ำหนักเถ้าลอย ส่วนผสมทั้งหมดจะถูกนำมาผสมกับน้ำและหล่อในแม่พิมพ์ขนาด 2.5 x 2.5 x 2.5 ลูกบาศก์เซนติเมตร ก่อนนำไปบ่มที่อุณหภูมิห้องเป็นเวลา 24 ชั่วโมง และบ่มต่อเนื่องอีก 7 และ 28 วัน และนำตัวอย่างขีโอพอลิเมอร์ซีเมนต์ไปทำการทดสอบสมบัติทางกายภาพ สมบัติเชิงกล และสมบัติทางเคมีของจีโอพอลิเมอร์ซีเมนต์ที่เตรียมได้ ผลการทดสอบพบว่าระยะเวลาที่ทำการบดส่วนผสมและปริมาณของโซเดียมไฮดรอกไซด์ที่เติมลงในส่วนผสม ส่งผลต่อสมบัติต่างๆของจีโอพอลิเมอร์เป็นอย่างมาก โดยส่งผลกับระยะเวลาการก่อตัว ค่ากำลังอัด และอัตราการไหล ผลการศึกษาพบว่าการเพิ่มปริมาณโซเดียมไฮดรอกไซด์ส่งผลให้ค่ากำลังอัดสูงขึ้น และไม่ควรเกิน 8% โดยค่ากำลังอัดสูงสุดที่ได้คือ 21.16 MPa ในอัตราส่วนโซเดียมเมต้าซิลิเกต/แคลเซียมไฮดรอกไซด์/โซเดียมไฮดรอกไซด์ 46:46:8 ที่ผ่านการบดเป็นเวลา 24 ชั่วโมง

Exploiting Quadratic Unconstrained Binary Optimization And Column Generation For Solving Vehicle Routing Problem With Discretized Time Windows, Krittin Phornsiricharoenphant

Chulalongkorn University Theses and Dissertations (Chula ETD)

No abstract provided.

Change Of Metal Oxidation State At High Temperature, Impact Of Temperature And Reactive Gases, Yegor Nikitin

Dissertations and Theses

The fundamental understanding of gas-solid reactions enables a wide range of applications to be developed and improved. Specifically, the use of metal-based materials is critical to ensuring robust, safe, and long-term operations. For example, in power systems where boilers are used to generate steam for heat or electricity generation the use of stainless metal alloys is critical to allow high quality steam to be produced in a very harsh environment. Alternatively, in catalysis, the use of metal doped heterogeneous catalysts are essential in achieving selectivity and conversion performance for chemical synthesis to emissions abatement. Typically, these metal alloys must withstand …

Synthesis Of Novel 5-Aryl 2’-Deoxyuridine And 2’-Deoxycytidine Analogues, Kevin E. Persaud

Dissertations and Theses

Briefly, the following report details a synthetic route to prepare 5-phenyl-2’-deoxycytidine analogues. This multistep synthesis began with silyl protection of the 3’- and 5’-hydroxyl groups of 5-iodo-2’-deoxyuridine. Next, the installation of a phenyl ring at the C5 position of the nucleobase via a Suzuki-Miyaura cross-coupling reaction, yielding 5-phenyl-2’-deoxyuridine (5-PdU). After that, modification of the obtained 5-PdU at the C4 position was performed with benzotriazole-1-yl-oxy-tris-(dimethylamino)-phosphonium hexafluorophosphate (BOP, a peptide-coupling agent) and a base (cesium carbonate) to activate the amide group of the uridine nucleobase for subsequent displacement with a variety of amines. Modification of the C4 position resulted in protected 5-phenyl-2’-deoxycytidine …

Molecular-Level Design Of Heterometallic Precursors For Rechargeable Battery Cathode Materials, Yuxuan Zhang

Electronic Theses & Dissertations (2024 - present)

The synthetic methods for rechargeable battery cathodes are rapidly evolving along with the continuous advancement of the materials themselves. Utilizing precursors for the synthesis of Li- and Na-ion cathode materials are known to ensure a phase-pure product with isotropic element distribution, thereby further enhancing the electrochemical properties of the cathode material. As more cathode materials with complex compositions continue to emerge, the strategies for designing the corresponding precursors are also getting diversified. One of the most promising directions is the employment of single-source precursors (SSPs), defined as molecules that contain all necessary elements in the proper ratio and decomposable under …

Structural Biology Of Diaphanous-1 And Its Role In Human Pathology, Gregory G. Theophall

Electronic Theses & Dissertations (2024 - present)

DIAPH1 is diaphanous related formin which polymerizes actin into filaments and is important to cytoskeleton dynamics.[1, 2] The dysregulation and aberrant activation of DIAPH1 is known to cause deafness[3, 4] and clotting disorders,[5] and is recently implicated in the inflammatory responses associated with cardiovascular and diabetic pathology.[6-9] Despite this, activation of the full length structure and its regulation are poorly understood.[10-12] Therefore, the main objective of this dissertation is to explore the structural, autoinhibitory, and regulatory properties of DIAPH1 in the context of disease pathology. Herein, I show that DIAPH1 has a dynamic structure which is regulated through negative cooperativity, …

Effect Of Annealing On Photoluminescence From Defects In Gan, Oleksandr Andrieiev

Theses and Dissertations

Annealing is a critical process in modern GaN technology, essential for achieving p-type conductivity by activating the Mg_Ga acceptor, as first demonstrated by Shuji Nakamura in the early 1990s. Despite the omnipresence of hydrogen as an impurity in GaN crystals, the precise mechanisms governing hydrogen diffusion and acceptor passivation remain only partially understood. The presented research investigates the effects of annealing-induced activation and hydrogen passivation on C and Be acceptors in GaN grown by MOCVD, HVPE, and MBE methods. We explored these effects by using several annealing techniques, gas compositions, and thermal regimes. A transient behavior between the C …

Lessons Learned From Laboratory Study And Field Application Of Re-Crosslinkable Preformed Particle Gels Rppg For Conformance Control In Mature Oilfields With Conduits/Fractures/Fracture-Like Channels, Baojun Bai, Thomas P. Schuman, David Smith, Tao Song

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

This Paper Surveys the Role of Re-Crosslink able Preformed Particle Gels (RPPG) in Addressing Conformance Challenges within Mature Oilfields. Despite Widespread Preformed Particle Gel (PPG) Application in 15,000+ Wells, their Limitations in Sealing Fractures and Conduits Prevalent in Mature Reservoirs Have Driven the Development of RPPG Formulations. Synthesized in Various Sizes from Micrometer to Millimeter Levels, These Environmentally Friendly RPPGs Are Tailored for Diverse Reservoir Conditions. Findings Showcase the Successful Laboratory-Scale Creation and Upscaling of RPPG Products, Offering Adaptability to Temperatures from 20 to 175°C, Customizable Sizes, Swelling Ratios (5 to 40 Times), and Re-Crosslinking Times Spanning Minutes to Days. …

Molecular Understanding And Design Of Deep Eutectic Solvents And Proteins Using Computer Simulations And Machine Learning, Usman Lame Abbas

Theses and Dissertations--Chemical and Materials Engineering

Hydrophobic deep eutectic solvents (DESs) have emerged as excellent extractants. A major challenge is the lack of an efficient tool to discover DES candidates. Currently, the search relies heavily on the researchers’ intuition or a trial-and-error process, which leads to a low success rate or bypassing of promising candidates. DES performance depends on the heterogeneous hydrogen bond environment formed by multiple hydrogen bond donors and acceptors. Understanding this heterogeneous hydrogen bond environment can help develop principles for designing high performance DESs for extraction and other separation applications. This work investigates the structure and dynamics of hydrogen bonds in hydrophobic DESs …

Measuring The Properties Of Rod-Shaped Bacteria By Single-Entity Electrochemistry, Ashley Tubbs

Theses and Dissertations

Antibiotic-resistant bacteria pose a significant and escalating threat to hospitals around the world, necessitating the development of rapid and sensitive detection methods. Single-entity electrochemistry has emerged as a promising approach for detecting and identifying such bacteria, and monitoring the efficacy of antibiotics in real-time. Herein, we employ the translational diffusion equation for circular cylinders to predict the collision frequency of rod-shaped bacteria, informing our experimental setup. Our work demonstrates that lab-fabricated Pt ultramicroelectrodes can sensitively detect bacteria at femtomolar concentrations under migration-controlled conditions. Further, we present a method implemented in MatLab to automate the analysis of step-like signals observed in …

Asymmetric Cuh-Catalyzed Reductive Coupling Of Allenamides With Carbonyl And Imine Electrophiles, Stephen Collins

Theses and Dissertations

The carbon scaffold of many drugs and natural products contain multiple stereogenic centers bearing heteroatoms. As a result of this, chemists have long sought methods to efficiently install these multi-heteroatom functionalities. Reductive coupling reactions have been extensively studied over the past decades, and the allylation of carbonyls via the reductive coupling approach has been a key method for generating chiral allylic alcohols. This work utilizes inexpensive Cu for the asymmetric reductive coupling of allenamides with carbonyls or imines to simultaneously install two heteroatoms (either oxygen and nitrogen or nitrogen and nitrogen, respectively) onto the product. These molecules have a polarity …

Scattering Of Larger Molecules – Part 1: General Discussion, Dmitri Babikov

Chemistry Faculty Research and Publications

No abstract provided.

Inhaling The Unseen: Exploring The Presence Of Microplastics In The Human Respiratory Tract, Kara Coffman-Rea

Graduate Research Theses & Dissertations

Microplastics (plastic pieces less than 5 mm) have emerged as a pervasive form of pollution acknowledged as a universal threat to both environmental and human health. Their small size and widespread distribution pose significant risks to marine life, terrestrial ecosystems, and ultimately human health. Microplastics have been reported in food and drink items designated for human consumption, in cosmetics and consumer goods designed for human use, and within the air we breathe, each providing an entry route for microplastics to enter the human body. Recently, microplastic particles have been detected in a variety of human tissue samples (e.g., lung tissue). …

Addressing The Effects Of Counterion Size On The Properties Of Electrochemically Doped Conjugated Polymers, Kyle Baustert

Theses and Dissertations--Chemistry

Conjugated polymers (CPs) are an emerging class of materials that are attractive for many applications due to their low cost, flexibility, and ease of processing. Both chemical and electrochemical doping of CPs is done to alter important properties such as their electrical conductivities and optical absorbances. This ability to tune their properties allows for their use in devices such as organic electrochemical transistors (OECTs) for biosensing and bioelectronics, electrochromic devices for color changing windows, as well as wearable thermoelectrics to use body heat to power wearable electronics. There are several factors that can influence the properties of doped CPs including …

Single-Atom Catalysts For Electrochemical Energy Conversion: Copper Single-Atom Catalyst For Oxygen Reduction Reaction And Quantification Of Site Density By Co Stripping Voltammetry, Dawatage Perera

Theses and Dissertations--Chemistry

Fuel cells are considered a promising technology for achieving cleaner and more sustainable energy production and utilization. However, one of the current major challenges is the economic viability associated with the extensive use of Pt group metal (PGM) catalysts, particularly on the cathode side. Therefore, non-PGM single-atom catalysts (SACs) have received considerable attention as alternatives for PGM catalysts in the oxygen reduction reaction (ORR), which occurs at the cathode of the fuel cell. Among various SAC structures, the non-PGM/nitrogen-doped carbon-based structure (M-N-C) stands out for its excellent ORR performance.

Chapter 2 illustrates the use of copper metal in place of …

Effect Of Π-Conjugated Ligands And A* Site Organic Cations On The Energetic Properties And Photovoltaic Performance Of Metal Halide Perovskites, Harindi R. Atapattu

Theses and Dissertations--Chemistry

Metal halide perovskites have gained interest in optoelectronic applications such as photovoltaics, lasers, LEDs, transistors, and photodetectors due to their excellent semiconducting properties considering their low cost. Metal halide perovskite (HP) photovoltaics have rapidly increased in power conversion efficiency (PCE), which now exceeds 25%. HPs have gained attention in these applications due to their high tolerance towards defects, long charge carrier diffusion lengths, high charge carrier mobility, high optical absorption, and bandgaps that are tunable over a large range. Even though HP photovoltaic PCEs are improved these are still not commercially available due to them showing lower stability and energy …

Understanding Of Processing Additives Influence In Tin Halide Perovskites: Chemistry, Defect, And Photovoltaic Performance, Syed Rahmath Ullah Joy

Theses and Dissertations--Chemistry

Metal halide perovskite semiconductors have attracted much interest for various applications, such as solar cells, light emitting diodes, photodetectors, and lasers, due to their excellent optoelectronic properties. Photovoltaic cell development is centered on Pb-based perovskites, which have equal photovoltaic performance compared to the traditional silicon photovoltaic. But concerns arising from the usage of toxic lead metal have motivated the research community to seek an alternative derivative. Among those, tin halide perovskites show much promise as an alternative to Pb-counterparts due to their ideal bandgap for single junction photovoltaics and similar optoelectronic properties to Pb perovskites. Nevertheless, tin perovskites suffer from …

Synthetic Strategies Toward The Development Of Stable Gold-Based Anticancer Agents And Their Mechanistic Insight, Adedamola Arojojoye

Theses and Dissertations--Chemistry

Despite notable advancements in the design and synthesis of novel chemotherapeutic drugs, cancer continues to be a leading cause of death in the United States. Metallodrugs, especially Au complexes, have played a prominent role in the search for the next generation of chemotherapeutic agents. Herein, I report on the synthetic strategies towards the rational design of stable Au (Au)-based agents, study their reactivity in biological environment, and offer insights into the cytotoxic mechanism of action in cancer. Chemotherapeutic Au compounds exist mainly in +I or +III oxidation states. Repurposing of the Au(I) FDA approved auranofin for the treatment of diseases …

Synthesis, Functionalization, And Application Of Polymeric Membrane Blends Of Polysulfone, Poly-Ether Ether-Ketone, And Natural Fiber Additive Biochar For Optimal Water Treatment., Abelline Katusiime Fionah

Theses and Dissertations--Chemistry

According to the Center for disease control (CDC), an estimated 1.7 to 2.2 million persons die from waterborne diseases annually. The majority of individuals dying from diseases resulting from unsafe drinking water, such as diarrhea and gastroenteritis, are children. This has in turn created a global water crisis. Different methods have been developed to treat contaminated water in response to the global water crisis such as adsorption, filtration, ozonolysis, catalysis, etc. Of the methods available, filtration via polymeric membranes has been one of the most successfully applied. A membrane is a thin semi-permeable barrier (often made of a polymer) used …

Applying Synchrotron Saxs And Xas To Study The Microstructure Of Energy Conversion And Storage Materials, Lingzhe Fang

Graduate Research Theses & Dissertations

The microstructure of energy conversion and storage materials is a key determinant of physical properties and electrochemical performance. Synchrotron X-ray techniques, with their strengths of high flux and exceptional brightness, play an irreplaceable role in understanding nano and sub-nano structures. This helps the study of reaction mechanisms and benefits material design in energy conversion and storage area. Electrifying CO2 transformation using renewable energy offers a carbon-neutral solution to CO2 recycling and fuel generation. Among various feedstocks from the CO2 reduction reaction, CO, HCOOH, and CH4 have approached the performance thresholds for industry implementation. The application of single atom catalysts (SACs) …

Gas-Phase Mass Spectrometry Studies Of Ternary Metal Carboxylate Complexes, Anthony James Fanizza

Graduate Research Theses & Dissertations

In the wake of climate change from rising CO2 emissions and with peak oil looming, the dive into sustainable fuels and energy is becoming increasingly essential. This dissertation investigates ternary ligand-metal cationic complexes for potential catalytic applications in the decarboxylation of carboxylic acids to produce bioavailable and carbon-neutral fuel sources. By utilizing gas-phase reactivity studies via mass spectrometry, namely, collision-induced dissociation and ion-molecule reactions, mechanisms can be elucidated in a regulated chemical environment. When paired with density functional theory calculations for molecular geometries, chemical interactions, charge densities, and energetics, system efficiencies can be further clarified presenting a more complete mechanistic …

Pathology And Diagnosis In Inflammatory-Related Diseases: Covid-19 And Age-Related Macular Degeneration, Zane Russell Lacasse

Graduate Research Theses & Dissertations

Chronic inflammation and dysfunctional inflammatory responses are believed to be contributing factors to the severity of many diseases. Since the emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), it has been recognized that levels of inflammatory markers and the severity of coronavirus disease-2019 (COVID-19) cases are closely related. The work within this dissertation begins with establishing an alternative platform for the diagnosis of COVID-19 and explores ways to enhance the diagnostic utility of this platform. An alternative route for COVID-19 diagnosis was explored using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-ToF MS). The platform utilizes a non-invasive sampling technique …

Dna I-Motifs: Biophysical Characterization And Structure-Property Correlation As Foundation For Functional Material Design, Alexander Minasyan

Graduate Research Theses & Dissertations

Over the past decades, nucleic acids have emerged as crucial frameworks with significance in biological systems and functional material engineering. Cytosine-rich deoxyribonucleotide sequences can form quadruplex structures a.k.a. i-motifs. Recently, i-motifs have attracted scientific interest in biological and material design areas.

In this work, we systematically investigate an effect of structured and unstructured modifications such as hairpins, stems, loops and overhangs on the kinetic and thermodynamic properties of DNA i-motifs. We demonstrate that the modifications can influence i-motif’s stability and folding/unfolding rates: thus, double stranded stems and hairpins are the best at stabilizing i-motifs and increasing kinetic rates of folding. …