Chemistry Commons^™

Explorations Of Multi-Carboranyl Thiols And Phosphines, Jared Ross Riffle

Theses and Dissertations

In order to ascribe the impact of substituent groups on the bis-ortho-carborane, closo-{C2B10}-closo-{C2B10} multi-cluster system, the first sulfur-containing biscarborane derivatives were synthesized. Biscarborane dithiol, disulfide, bis(methyl)thioether, as well as multiple dithiolate salts were structurally characterized. The exceedingly long C–C bonds and shortened C–S bonds in biscarborane dithiol and its doubly deprotonated dithiolate salts are indicative of significant delocalization of electron density from the sulfur atoms into the cluster. Additionally, a new concept of ligand ambiphilicity is described where, instead of the involvement of only a single center in a ligand, this amphiphilicity relies on the redox behavior of the indirectly …

Building A Framework For Analyzing Non-Linear And Multidimensional Kinetics, Mainak Dhar

Theses and Dissertations

Many materials exhibit multiple rates of molecular relaxation due to structural complexities. Standard linear and one-dimensional kinetic cannot extract all the necessary dynamic information about these systems. This dissertation contributes to an overarching scheme to develop new non-linear and multidimensional kinetic experiments to obtain this information. The studies span computation and experiments, picosecond to second timescales, and both single-molecule and pulsed-laser kinetics

Single-molecule kinetics experiments yield time series that contain information about unique structural and dynamic properties of materials. However, these time series are noisy, and data analysis is challenging. Parametric methods are computationally intensive and require strong, unverifiable assumptions …

Expanding Tailored Nanomaterials With Precise Spatial And Morphological Control, Mengxue Zhang

Theses and Dissertations

Multicomponent nanocomposites with precise spatial control are important for diverse fields spanning from energy conversion to optoelectronics and catalysis. Traditional methods using hydrophilic interactions alone are limited to random mixtures when multiple nanoparticle (NP) types are combined. To improve capabilities, a new strategy for polymer micelle design combining orthogonal hydrophilic (H) and fluorophobic (F) interactions to independently control two distinct NP populations was developed.

Initial research aimed at understanding F-interaction adjustments, which further enabled the switchability of FNP distribution states (dispersion vs aggregation) within polymer films through immersion annealing. Next, dual-NP assembly was examined using a diblock poly (H-b-F) where …

The Design And Optimization Of Optical Systems For The Detection And Characterization Of Phytoplankton, Caitlyn M. English

Theses and Dissertations

Phytoplankton are among the smallest organisms found in marine and freshwater ecosystems. Despite their small size, phytoplankton play a vital role in sustaining life on Earth as primary producers. Through oxygenic photosynthesis phytoplankton are also responsible for large scale carbon fixation and oxygen production. The distribution of phytoplankton in a given water resource can exhibit a high degree of variability across time and space, and this is in large part due to their varying sensitivities to environmental conditions such as resource availability and grazing by predator organisms. As such, phytoplankton community structure is widely used as an investigative tool for …

Thermodynamic Study Of Ligand Coordination On Lead Halide Perovskite Quantum Dots, Bishal Adhikari

Theses and Dissertations

Inorganic lead halide perovskite (ILHP) has been extensively studied in thin films and bulk crystals as promising materials for their photovoltaic and optoelectronic properties. These are stable enough to be prepared as colloidal quantum dots that can be dispersed, deposited and used to achieve quantum confinement; however, selection of the suitable surface passivating ligand remains challenge for long term stability of the colloidal quantum dots. Several ligand coordination chemistries used to achieve greater stability or specific functions: these can be installed at time of synthesis in some cases they can also be installed to preexisting quantum dots by ligand exchange …

Kinetic Control And Trapping In The Supramolecular Polymerization Of M-Terphenyl Bis-Urea Macrocycles, Sophya V. Garashchuk, Gamage Isuri P. Wijesekera, Isabella G. Rushton, Vaibhavi A. Samant, Fahidat A. Gbadamosi, Dr. Md Faizul Islam, Sophya V. Garashchuk, Prof. Dr. Linda S. Shimizu

Faculty Publications

Herein, we examine pathway complexity in the supramolecular polymerization of a novel m-terphenyl bis-urea macrocycle. Designed to induce kinetically metastable states, the macrocycle‘s concentration-dependent aggregation was studied via 1H NMR and IR spectroscopy in THF and CHCl₃. Temperature-dependent UV-Vis spectroscopy in water/THF revealed a cooperative nucleation-growth mechanism, indicated by a shift in λmax to longer wavelengths upon cooling. Morphological studies using DLS, AFM, and SEM demonstrated fibrous aggregate formation. Thermal hysteresis observed in assembly-disassembly cycles indicated kinetically trapped species, with cooling governed by kinetic control and heating by thermodynamic processes. Deviations in ΔH values during cooling, compared to van′t …

Synthesis Of A Series Of Rare-Earth-Based Multi-Anion Chalcogenide Iodides Re3Si2SeXS8-XI (Re = La, Ce, Pr, And Nd) Using The Flux-Assisted Boron-Chalcogen Mixture Method, Gopabandhu Panigrahi, Habiba Binte Kashem, Gregory Morrison, Hans Conrad Zur Loye

Faculty Publications

Single crystals and polycrystalline powders of rare earth mixed chalcogenide iodides La3Si2Se1.21S6.79I, Ce3Si2Se1.39S6.61I, Pr3Si2Se1.22S6.78I, and Nd3Si2Se1.18S6.82I were prepared using the reactive flux-assisted boron-chalcogen mixture (BCM) method at 850 °C. All compounds crystallized in the monoclinic crystal system, space group C2/c (space group number 15). The series adopts the La3Si2O8Cl structure type, containing isolated SiQ4 tetrahedra connected by REQ8 (RE = La, Ce, Pr and Nd) polyhedra; this arrangement creates tunnels that are filled by I atoms. The partial substitution of S by Se was carried out to modulate the optical properties. Phase pure samples and uniform solid solutions were obtained …

Nanostructure Retention To 1100 °C In Soft-Templated Niobium Tungstates Using Dual-Carbon Strategy, Sean C. Wechsler, Alexander Gregg, Coby S. Collins, Santosh Kiran Balijepalli, Morgan Stefik

Faculty Publications

Mesoporous metal oxides (MMOs) have diverse applications including energy storage, catalysis, and separation membranes. Block polymer structure directing agents enable the control of morphology and pore size, however preservation of the nanostructure is often limited to a narrow range of heat treatment temperatures which constrains the tailoring of defect chemistries. High temperature treatments typically lead to collapse of the porous structure as surface area is reduced during crystal growth. Here, using a mesoporous niobium tungstate it is shown that neither in situ carbon generation nor ex situ carbon infiltration alone enable preservation of the ordered mesostructure at temperatures high enough …

Associations Between Social Determinants Of Health And Mental Health Disorders Among U.S. Population: A Cross-Sectional Study, S. Tanarsuwongkul

Faculty Publications

Aims

The impact of social determinants of health (SDOH) on mental health is increasingly realized. A comprehensive study examining the associations of SDOH with mental health disorders has yet to be accomplished. This study evaluated the associations between five domains of SDOH and the SDOH summary score and mental health disorders in the United States.

Methods

We analyzed data from a diverse group of participants enrolled in the All of Us research programme, a research programme to gather data from one million people living in the United States, in a cross-sectional design. The primary exposure was SDOH based on Healthy …

Durable Oxyfluoride Waste Forms For Salt Wastes From Molten Salt Reactors, Alevtina A. Maksimova, Jake W. Amoroso, Matthew Page, Gregory Morrison, Hans Conrad Zur Loye

Faculty Publications

Molten salt reactors (MSRs) are promising technology to replace traditional light and heavy water reactors in the near future. Waste management for MSRs, however, remains a pressing concern that needs to be resolved prior to realizing deployment of MSRs. Specifically, the generated salt waste needs to be safely sequestered, a task made difficult by the high solubility of the salt waste that can cause the release of radionuclides into the environment. This work demonstrates a new approach to immobilize multiple fluoride salts into a single waste form by converting highly-soluble fluorides to durable and stable oxyfluorides. Notably, we report a …

Modification Of Nanoparticles For Designed Interfaces, Tony Lee Neely, Jr.

Theses and Dissertations

The work contained herein, is focused on the design, synthesis, and characterization of polymer nanocomposite interfaces and the property enhancement afforded from said interface design. Through the use of reversible addition fragmentation chain transfer (RAFT) polymerization for the grafting of polymer chains to silica nanoparticles, the surface of silica nanoparticles can be manipulated to tune the properties of the nanocomposite as a whole.

In the first part of this work, heterogeneity is introduced onto the surface of silica nanoparticles via a sequential RAFT polymerization to afford a bimodal brush system. A densely grafted, short brush population is polymerized from the …

Molten Flux Synthesis Of Plutonium (Iv) Silicates K2Pusi2O7 And Rb2Pusi6O15, Travis K. Deason, Gregory Morrison, Amir Mofrad, Jake Amoroso, David Diprete, Theodore M. Besmann, Shanna L. Estes, Hans Conrad Zur Loye

Faculty Publications

Few plutonium containing silicates have been reported in the literature and only one other tetravalent plutonium silicate structure has been reported using the flux growth method. With the goal of understanding actinide incorporation into silicates, we describe herein two new plutonium (IV) silicates, Rb2PuSi6O15 and K2PuSi2O7, synthesized using a mixed alkali chloride/alkali fluoride flux growth. Both structures crystallize in the C2/c space group with lattice parameters a=24.2980(10) Å, b=7.1466(3) Å, c=17.2025(8) Å and 96.6560(10)° for Rb2PuSi6O15, and a=9.9478(2) Å, b=5.59820 (10) Å, c=13.1848(2) Å, and 105.7400(10)° for K2PuSi2O7. Comparisons to the synthesis of other reported alkali actinide silicates (Ce, U, …

Capacity-Weighted Figures-Of-Merit For Battery Transport Metrics, Cj Sturgill, Christopher Sutton, Julian Schwenzel, Morgan Stefik

Faculty Publications

New battery materials with improved transport are needed. Typical measurements yield widely varying voltage-dependent diffusivities and reporting practices are diverse. Some materials (e.g. first-order phase change) have most redox occur at a specific voltage and may be sufficiently represented by singular transport metrics. Many rapid intercalation materials, however, exhibit second-order phase transitions with redox over a broad voltage range. How should such cases be compared? The use of capacity-weighted average values is suggested where voltage-dependent metrics are consolidated into representative descriptors as figures-of-merit. Examples are elaborated where differential capacity (dQ/dV) is used to derive a …

Na2B12Si6Se18: A Novel B12-Cluster-Containing Quaternary Selenoborate Framework Material, Gopabandhu Panigrahi, Hunter B. Tisdale, Gregory Morrison, Hans Conrad Zur Loye

Faculty Publications

We report the successful synthesis of the new quaternary, three-dimensional Na₂B₁₂Si₆Se₁₈ material using a solid-state synthesis route. This compound is characterized by a unique framework structure that features the rare icosahedral [B₁₂]¹⁰⁺ cation which is connected via Si2Se6 polyhedral units into a 3D framework structure with Na+ ions located inside the channels. The Na₂B₁₂Si₆Se₁₈ compound crystallizes in the cubic crystal system in the space group Im, with lattice parameter a = 11.91110(10) Å and unit cell volume of 1689.88(4) ų. …

Investigation Of Magnesium-Potassium Phosphates As Potential Nuclear Waste Form For The Immobilization Of Minor Actinides, Hans Conrad Zur Loye, Petr Vecernik, Monika Kiselova, Vlastislav Kašpar, Hana Korenkova, Vlastimil Miller, Petr Bezdicka, Jan Šubrt, Natalija Murafa, Volodymyr Shkuropatenko, Sergey Sayenko

Faculty Publications

Several recent studies have evaluated technologies of spent nuclear fuel processing specifically for solidifying transuranic (TRU) waste as a by-product of fission. Of the TRU group, plutonium and the minor actinides will be responsible for the bulk of the radiotoxicity and heat generation of spent nuclear fuel in the long term (300 to 20,000 years). In this study, we investigated magnesium potassium phosphate (MKP)-based compounds as host waste forms for the encapsulation of inactive trivalent Nd and Sm as analogues of the minor trivalent actinides, Am and Cm. Waste forms were fabricated under ambient atmospheric conditions by adding 5 wt.% …

Examination Of Photoinduced Radicals In Two Crystal Forms Of Triphenylamine Bis-Urea Macrocycles, Md Faizul Islam, Gamage Isuri P. Wijesekera, Anmon J. Sindt, Mark D. Smith, Linda S. Shimizu

Faculty Publications

This study probes two solvates of triphenylamine (TPA) bis-urea macrocycle 1 and their activated structures to evaluate their maximum photoinduced radicals (PIRs), the subsequent decay of the radicals, and their regeneration. The hierarchical assembly of TPAs shows promise in stabilizing less substituted derivatives, potentially expanding the utility of TPAs that lack stabilizing para-substituents. Single crystal structure analysis reveals that host 1 adopts a planar conformation with the two ureas pointing in opposite directions when dimethoxyethane (DME) is encapsulated within the channel. Whereas previously, 1 adopted a bowl-shaped conformation with the two ureas pointing in the same direction (syn …

Examination Of Photoinduced Radicals In Two Crystal Forms Of Triphenylamine Bis-Urea Macrocycles, Md Faizul Islam, Gamage Isuri P. Wijesekera, Ammon J. Sindt, Mark D. Smith, Linda S. Shimizu

Faculty Publications

This study probes two solvates of triphenylamine (TPA) bis-urea macrocycle 1 and their activated structures to evaluate their maximum photoinduced radicals (PIRs), the subsequent decay of the radicals, and their regeneration. The hierarchical assembly of TPAs shows promise in stabilizing less substituted derivatives, potentially expanding the utility of TPAs that lack stabilizing para-substituents. Single crystal structure analysis reveals that host 1 adopts a planar conformation with the two ureas pointing in opposite directions when dimethoxyethane (DME) is encapsulated within the channel. Whereas previously, 1 adopted a bowl-shaped conformation with the two ureas pointing in the same direction (syn …

Accurate Crystal Structure Prediction Of New 2d Hybrid Organic–Inorganic Perovskites, Nima Karimitari, William J. Baldwin, Evan W. Muller, Zachary J.L. Bare, W. Joshua Kennedy, Gábor Csányi, Christopher Sutton

Faculty Publications

Low-dimensional hybrid organic–inorganic perovskites (HOIPs) are promising electronically active materials for light absorption and emission. The design space of HOIPs is extremely large, as a variety of organic cations can be combined with different inorganic frameworks. This not only allows for tunable electronic and mechanical properties but also necessitates the development of new tools for in silico high throughput analysis of candidate materials. In this work, we present an accurate, efficient, and widely applicable machine learning interatomic potential (MLIP) trained on 86 diverse experimentally reported HOIP materials. This MLIP was tested on 73 experimentally reported perovskite compositions and achieves a …

Table Of Contents

Journal of the South Carolina Academy of Science

No abstract provided.

The Effect Of Different Vegetable Oils (Macadamia Nut Oil And Walnut Oil) On The Coefficient Of Friction As A Finish For Oak Wood, Lee Dillon

Journal of the South Carolina Academy of Science

Slipping due to insufficient friction with flooring can cause fatal injuries in workplaces and homes. Oak wood flooring is commonly used in construction to build these environments. In the manufacturing process, wood finishing is conducted at the end of the process to strengthen the properties and longevity of the wood, although it could impact the coefficient of friction (COF) causing slip falls. Vegetable oils, such as macadamia nut and walnut oils, used as wood finishes have gained prominence due to their beneficial aspects to the environment. However, little is known about their effectiveness as a safe coating for wood floors. …

Cortisol And Alpha-Synuclein Stability In Saliva Under Varying Storage And Handling Conditions, Mo Zheng, Sujata Srikanth, Jeremiah Carpenter, Delphine Dean

Journal of the South Carolina Academy of Science

Parkinson’s disease (PD) is a progressive neurodegenerative disorder characterized by motor impairments and non-motor symptoms, significantly impacting patients' quality of life. Currently, cerebrospinal fluid (CSF) is the primary biofluid used for PD biomarker studies, notably α-synuclein, despite the invasive nature of lumbar puncture procedures. Recent work has shown that some of these PD biomarkers have been measured in saliva. As an alternative to CSF, saliva can be non-invasively self-collected by patients repeatedly over time to monitor biomarker levels. However, the stability of these biomarkers in saliva needs to be evaluated before saliva can be considered for patient self-collection studies. Therefore, …

Potential Nec2/Nek1 Inhibitor And Inh1 Analog N-[4-(2,4-Dimethylphenyl)-2-Thiazolyl]-4-Pyridinecarboxamide Via Hantzsch Thiazol Condensation, Robert E. Lee Sr, Isabella G. Mcdonald, Paige E. Heiple, Lukas D. Shelton

Journal of the South Carolina Academy of Science

The potential active pharmaceutical ingredient (API), N-[4-(2,4-Dimethylphenyl)-2-thiazolyl]-4-pyridinecarboxamide (6) is a cancer cell metabolism mitosis inhibitor via the Nek2 and Hec1 enzymes. The three-step synthesis starts with the bromination of 1-(2,4-dimethylphenyl)ethan-1-one (1) using CuBr₂ to produce 2-bromo-1-(2,4-dimethylphenyl)ethan-1-one (2) with a yield of 90%.[i]^,[ii],[iii] Followed by Hantzsch thiazol ring synthesis as (2) reacts with thiourea (3) and, resulting in 4-(2,4-dimethylphenyl)thiazol-2-amine (4)[iv] in 80% yield. Finally, isonicotinoyl chloride hydrochloride (5) and (4) reacted to form the amide (6).[v]^{,[vi],[vii],[viii],[ix],[x]} Characterization of the final product was determined …

Examination Of Oncogenic Effects Of Environmental Pollutants, Andrew Ackerman, Matthew Behling, Brock Earley, Janay Vacharasin

Journal of the South Carolina Academy of Science

Chemical byproducts produced by surrounding industrial complexes have polluted the local estuaries of Georgetown, South Carolina for several decades¹. Previous studies completed by the EPA and SCDNR showed that the estuaries contained carcinogenic pollutants released from the local manufacturing plants¹. One of the mentioned pollutants was dioxins which are produced during the paper bleaching process². Dioxins are highly toxic compounds that have various carcinogenic effects on the organisms that inhabit the area. These previous studies were conducted over thirty years ago. Therefore, a current study to determine if chemical byproducts are contaminating local estuaries …

Striatal Beat Frequency Interval Timing Model With Microgravity Stressor, Jason Michael Fitzgerald, Sorinel Oprisan

Journal of the South Carolina Academy of Science

The Striatal Beat Frequency (SBF) model of interval timing uses frontal cortex (FC) neural oscillations to record the state of the brain at the reinforcement time Tc during fixed interval (FI) procedures in the long-term memory (LMEM). The state of the FC oscillators at any given time is stored in a short-term memory (SMEM) buffer. The SBF model uses the spiny neurons of the basal ganglia (BG) as coincidence detectors to produce beats between the content of the SMEM and LMEM. Across multiple species that can perform interval timing, there are two invariant properties: (a) the timing is precise, and …

Improvement Of Single-Crystal Structures Of Very Heavy Element Compounds By Refining Anomalous Dispersion Parameters, Florian Meurer, Gregory Morrison, Birgit Hischa, Hans Conrad Zur Loye, Christoph Hennig, Michael Bodensteiner

Faculty Publications

Refining the anomalous dispersion parameters of the four uranium compounds NaUF5, NaU2F9, Cs2(UO2)TiO4, and Cs2(UO2)Ti2O6 gave insights into the crystallographic model improvement of very heavy atoms. We found that the values for the dispersive and absorptive parts, f′ and f″, closely followed the X-ray absorption spectra on their L3, L2, and L1 edges. The obtained values are sensitive to the chemical environment at each crystallographically independent position. An incorrect treatment of the anomalous dispersion correction can lead to a wrong crystallographic model. The above-mentioned, already published structures were improved by this process. General guidelines were given for the crystal structure …

Mild Hydrothermal Crystal Growth Strategies For Complex Inorganic Metal Fluorides, Navindra Keerthisinghe

Theses and Dissertations

Inorganic metal fluorides have been investigated for their interesting magnetic and optical properties, their electrochemical behavior, and their ionic conductivity. Fluoride materials can accommodate metals in very low oxidation states, which can be advantageous for designing new magnetic materials. Specifically, mixed metal fluorides incorporating transition metal cations often exhibit interesting magnetic behavior, such as frustrated magnetism. However, many challenges are encountered during the synthesis of such fluoride materials, including the inability to perform reactions under ambient conditions and the involvement of toxic gases for fluorination during solid-state reactions. Therefore, solution growth techniques such as mild hydrothermal synthesis are currently utilized …

Synergetic And Orthogonal Switching In Dual Photochromic Metal-Organic Frameworks, Gina Rene Wilson

Theses and Dissertations

Cooperative behavior and orthogonal responses of two classes of coordinatively integrated photochromic molecules towards distinct external stimuli were demonstrated on the first example of a photo-thermo-responsive hierarchical platform. Synergetic and orthogonal responses to temperature and excitation wavelength are achieved by confining the stimuli-responsive moieties within a metal-organic framework (MOF), leading to the preparation of a novel photo-thermo-responsive spiropyran-diarylethene based material. Synergistic behavior of two photoswitches enables the study of stimuli-responsive resonance energy transfer as well as control of the photoinduced charge transfer processes, milestones required to advance optoelectronics development. Spectroscopic studies in combination with theoretical modeling revealed a nonlinear effect …

Electron Rich Cobaltocenium Derivatives As Tunable Mechanophores For Mechanochemistry, Luis Daniel Ramos

Theses and Dissertations

In this dissertation, metallocene-containing polymers are investigated and probed for tunability in mechanochemistry. These metallocene moieties are experimentally and computationally characterized.

In chapter 1, relevant background and recent developments of metallocene-containing polymers are discussed. Additionally, the field of mechanochemistry is briefly introduced including applications and future directions within the field.

In chapter 2, design and synthesis of these metallocene-containing polyelectrolytes via ring opening metathesis polymerization (ROMP) are outlined. These polymers then undergo mechanophore activation via ultrasonication and relevant analysis and characterization of polymers both before and after ultrasonication are detailed. These polymers are comprised of differing electron donating substituents on …

Metal-Organic Frameworks For Global Environmental Challenges, Kyoungchul Park

Theses and Dissertations

Over the past few decades, there has been a demand for improving nuclear waste administration due to a significant increase in the utilization of nuclear energy. The driving force for proper nuclear waste disposal is evident when considering past nuclear catastrophes—such as Chernobyl and Fukushima—where radionuclide contamination of large bodies of water sparked public concern. In order to manage such radioactive species, the emerging areas of radionuclide sequestration, storage, separation, and sensing must be addressed in the upcoming years. This dissertation presents a potential candidate for addressing these challenges, called metal-organic frameworks (MOFs). Due to their porosity, high surface area, …

Controlling Properties Of Hybrid Materials: Leaching Kinetics And Electronic Structure, Anna Berseneva

Theses and Dissertations

Hybrid materials are a unique class of materials that merge the properties of organic and inorganic building blocks. These materials are at the frontier of material science due to their wide modularity and applicability in numerous fields, ranging from catalysis to nuclear waste treatment. Unprecedented tunability of physical properties via changes in organic, inorganic moieties and their connectivity, enables for hybrid materials to address current challenges in the materials’ applications improving energy landscape.

The presented work consists of six chapters where the synthesis and design of new hybrid materials, fundamental understanding of electronic behavior and its modulation in organic-inorganic materials, …