Chemistry Commons^™

Modeling Hyperpolarized Nmr Phenomena In Optically Pumped Semiconductors, Michael Eric West

Arts & Sciences Graduate Student Theses and Dissertations

Nuclear magnetic resonance (NMR) is a widely-used technique that measures the local environments of nuclei. It is able to detect small differences in energy, making it a highly-valued tool. However, the technique is challenged by inherently low sensitivities, requiring either large sample volumes or long periods of time to overcome this. In semiconductors, optical pumping (OP) can overcome this low sensitivity by creating incredibly large and dynamic nuclear spin polarizations (``hyperpolarization''), which is detectable as a large NMR signal. The combined technique of optically-pumped NMR (OPNMR) is a valuable tool that can explore electronic and nuclear phenomena within semiconductors. In …

Cr3+ Assisted Energy Transfer For Mn2+ Doped Zinc Gallogermanate With Narrow And Bright Green Emission, Bhupendra B. Srivastava, Santosh K. Gupta, Swati Mohan, Allen Abraham, Adrian Portales, Yuanbing Mao

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

The objective of this work is to obtain bright green and tunable emission by dopant engineering. It has been achieved in zinc gallogermanate (ZGG) nanodiscs by utilizing Mn2+ and Cr3+ ions as dopant and co-dopant, respectively. Based on photoluminescence measurement, we have found that the Cr3+ co-dopant triggers bright green emission of Mn2+ dopant in the nanodiscs by acting as a bridge to efficiently transfer the emission from the ZGG host to Mn2+ ion. We have validated the efficacy of energy transfer by concentration dependent photoluminescence and lifetime measurement. There are only a few reports on green emitting bulk Mn2+ …

Further Astrochemical Insights From Bond Strengths Of Small Molecules Containing Atoms From The First Three Rows Of The Periodic Table, Edmund S. Doerksen, Ryan C. Fortenberry

Faculty and Student Publications

The atoms contributing to the strongest “single bonds” on the periodic table do not continue to produce the strongest “double bonds” or “triple bonds.” In fact, the opposite appears to be the case. This quantum chemical examination of nominal X = Y and X ≡ Y bonds in model molecules of atoms from the first three rows of the periodic table shows that the strongest “double bond” is in formaldehyde once the astrophysically-depleted Be and B atoms are removed from consideration. The strongest “triple bond” is a close match between acetylene and N2. However, these results indicate that astrophysical regions …

Thermal Properties Of 18f-Fdg Uptake And Imaging In Positron Emission Tomography Scans Of Cancerous Cells, Carleigh R. Eagle

PANDION: The Osprey Journal of Research and Ideas

Positron Emission Tomography (PET) scans can utilize a radioactive tracer, in this case 2-deoxy2-[fluorine-18] fluoro-D-glucose (¹⁸F-FDG), to visualize malignant tumors in cancer patients. The uptake was compared to glucose to understand the difference in thermal properties, which contribute to the ability to image the cancerous cells. The uptake of ¹⁸F-FDG by cancer cells and the imaging process of positron emission tomography were reviewed from a thermodynamic perspective. Gastrointestinal and neurological imaging techniques were reviewed to understand the role of PET imaging in different areas of the human body.

Faculty-Librarian Cooperation For Virtual Stem Based Courses: Creating Successful Learning Experiences For Undergraduate Students At Ucf, Sandy Avila, Nicole Lapeyrouse

Faculty Scholarship and Creative Works

This conference presentation was delivered at the Special Libraries Association annual virtual conference on August 12, 2021.

Session Abstract

In this session, University of Central Florida Chemistry Faculty, Dr. Nicole Lapeyrouse and Science Librarian, Sandy Avila will discuss their transition from in-person instruction to online learning during the pandemic and how their professional collaboration developed instructional resources for student success. Prior to COVID-19, a fruitful cooperative relationship was already in place, but quickly having to pivot to remote teaching and learning allowed for additional opportunities for unique experiences to be created. Those include use of open-educational e-texts, interactive online software …

Formation Of Microcages From A Collagen Mimetic Peptide Via Metal-Ligand Interactions, Jeremy Gleaton, Ryan W. Curtis, Jean Chmielewski

Department of Chemistry Faculty Publications

Here, the hierarchical assembly of a collagen mimetic peptide (CMP) displaying four bipyridine moieties is described. The CMP was capable of forming triple helices followed by self-assembly into disks and domes. Treatment of these disks and domes with metal ions such as Fe(II), Cu(II), Zn(II), Co(II), and Ru(III) triggered the formation of microcages, and micron-sized cup-like structures. Mechanistic studies suggest that the formation of the microcages proceeds from the disks and domes in a metal-dependent fashion. Fluorescently-labeled dextrans were encapsulated within the cages and displayed a time-dependent release using thermal conditions.

Correlation Effects On Intramolecular C-H...Oh And O-H...O Hydrogen Bond Interactions In Azelaic Acid: An Ab Initio Study, Sabina Kalata, Alina Huang, Ruben Parra

DePaul Discoveries

Electron correlation effects on both conventional, O-H…O, and nonconventional, C-H…O, intramolecular hydrogen bonds present in a selected azelaic acid folded conformation were evaluated ab initio using HF and MP2 methodologies. The relative strength of the hydrogen bonds was examined through different indicators derived from geometry, vibrational frequencies, and electron density along the hydrogen bond path. The HF method results in weaker O-H…O and C-H…O hydrogen bonds when compared with the corresponding results using the MP2 method. Additionally, the stability of the folded azelaic conformation is found to depend on the level of theory used. Accordingly, the zero-point corrected energies of …

High Altitude Ballooning As A Platform For Measuring Ozone Uptake Over Agricultural Landscapes, Thomas Sykora, Mark Potosnak

DePaul Discoveries

Measuring plant health is a key aspect in maximizing crop outputs. One often overlooked risk to crop fields is damage caused by stomatal ozone uptake; measuring this uptake is an important tool in understanding crop losses. Traditional methods for measuring plant ozone uptake are prohibitively expensive and rely on equipment that cannot easily be moved. Here, we propose high-altitude weather ballooning as a cost-effective alternative for measuring ozone uptake on a regional (~10 km) spatial scale. Ozonesounde data was obtained with weather balloons launched from the National Oceanic and Atmospheric Administration research station in Boulder, Colorado. This data was then …

The Variability Of Seawater Carbonate Chemistry In Two Florida Urban Mangrove Ecosystems, Alexandrina R. Rangel

All HCAS Student Capstones, Theses, and Dissertations

Anthropogenic carbon dioxide (CO₂) emissions into the atmosphere are yielding serious impacts across the world’s ocean, including ocean acidification, sea level rise, and increasing seawater temperature. However, these changes are not occurring uniformly across all marine ecosystems. Coastal ecosystems, such as mangroves, already experience extreme and variable environmental conditions due to natural biogeochemical and physical processes. The goal of this study was to document small-scale variability in two urban mangrove ecosystems to gain insight into how ocean acidification will manifest within these systems. Using a stand-up paddleboard, a suite of sensors, and traditional bottle sampling techniques, we measured …

Quantifying Phosphatidylethanol From Blood Samples, James V. Defrancesco, Majid Afshar

Chemistry: Faculty Publications and Other Works

Disclosed herein is a method for quantifying phosphatidylethanol (“ PEth ”), direct ethanol biomarker, from a blood sample using gas chromatography mass spectrometry. The method disclosed herein is useful for diagnosing acute and chronic alcohol abuse.

Nickel Catalyzed Electrochemical C-C Cross-Coupling Reactions, T. Leo Liu

Funded Research Records

No abstract provided.

Swir Emissive Rosindolizine Dyes With Nanoencapsulation In Water Soluble Dendrimers, Satadru Chatterjee, William E. Meador, Cameron Smith, Indika Chandrasiri, Mohammad Farid Zia, Jay Nguyen, Austin Dorris, Alex Flynt, Davita L. Watkins, Nathan I. Hammer, Jared H. Delcamp

Faculty and Student Publications

Shortwave infrared (SWIR) emission has great potential for deep-tissuein vivobiological imaging with high resolution. In this article, the synthesis and characterization of two new xanthene-based RosIndolizine dyes codedPhRosIndz andtolRosIndz is presented. The dyes are characterizedviafemtosecond transient absorption spectroscopy as well as steady-state absorption and emission spectroscopies. The emission of these dyes is shown in the SWIR region with peak emission at 1097 nm.TolRosIndz was encapsulated with an amphiphilic linear dendritic block co-polymer (LDBC) coded 10-PhPCL-G3 with high uptake yield. Further, cellular toxicity was examinedin vitrousing HEK (human embryonic kidney) cells where a >90% cell viability was observed at practical concentrations …

Swir Emissive Rosindolizine Dyes With Nanoencapsulation In Water Soluble Dendrimers, Satadru Chatterjee, William E. Meador, Cameron Smith, Indika Chandrasiri, Mohammad Farid Zia, Jay Nguyen, Austin Dorris, Alex Flynt, Davita L. Watkins, Nathan I. Hammer, Jared H. Delcamp

Faculty Publications

Shortwave infrared (SWIR) emission has great potential for deep-tissue in vivo biological imaging with high resolution. In this article, the synthesis and characterization of two new xanthene-based RosIndolizine dyes coded ^PhRosIndz and ^tolRosIndz is presented. The dyes are characterized via femtosecond transient absorption spectroscopy as well as steady-state absorption and emission spectroscopies. The emission of these dyes is shown in the SWIR region with peak emission at 1097 nm. ^TolRosIndz was encapsulated with an amphiphilic linear dendritic block co-polymer (LDBC) coded 10-PhPCL-G3 with high uptake yield. Further, cellular toxicity was examined in vitro using HEK (human embryonic …

The Development And Optimization Of A Two-Dimensional Lc-Qqq-Ms-Method For The Combined Analysis Of Synthetic Cannabinoids And Designer Cathinones In Urine, Holly Penefsky

Electronic Theses and Dissertations

The compounds and chemical compositions of synthetic cannabinoids and designer cathinones are designed to mimic the intoxicating effects of D⁹-tetrahydrocannabinol and amphetamines, respectively. In order to skirt existing drug laws, non-controlled ingredients are used, and the original chemical structures of current drugs are being modified using analogs or derivatives. These continually changing chemical compositions pose a problem for policymakers, and forensic and analytical scientists, as users are able to attain a “legal high” and avoid detection in standard drug screens. Commonly, toxicology laboratories utilize a screening method, such as immunoassay, for the presumptive identification of designer drugs. When …

Impacts Of Oil And Gas Wastes On Landfill Leachate, Sewage Treatment Plants, And The Environment, Lauren Badertscher

Electronic Theses and Dissertations

Between January 2011 and March 2021 oil and gas wells in Pennsylvania produced

305,637,795 barrels of liquid waste and 6,992,957 tons of solid waste with the majority from

Marcellus Shale unconventional wells. This waste is not considered hazardous and over 89% of

the solid waste generated by unconventional and conventional oil and gas extraction has been

disposed of in landfills over the past decade. This study examined trends in the quantity of waste

produced and methods of disposal. Landfills accepting this waste were identified and their

general method of leachate treatment, using onsite facilities or offsite at wastewater treatment

plants, …

Skin Permeation Of Nickel, Cobalt And Chromium Salts In Ex Vivo Human Skin, Visualized Using Mass Spectrometry Imaging, Lina Hagvall, Masoumeh Dowlatshahi Pour, Jiabao Feng, Moshtak Karma, Yolanda Hedberg, Per Malmberg

Chemistry Publications

Skin permeation and distribution of three of the most common skin sensitizers was investigated using a previ-ously developed animal-free exposure method combined with imaging mass spectrometry. Nickel, cobalt, and chromium (III) salts were dissolved in a buffer and exposed to human skin ex vivo, to be analyzed using time of flight secondary ion mass spectrometry (ToF-SIMS). Our findings demonstrate that metal haptens mainly accumulated in the stratum corneum, however all three metal sensitizers could also be detected in the epidermis. Cobalt and chromium (III) species penetrated into the epidermis to a larger extent than nickel species. The degree of penetration …

Development Of Standard Operating Procedure With Modified Method To Quantify Benzene And Other Volatile Organic Compounds In Air Samples Using Gas Chromatography, Heather Hall

Electronic Theses and Dissertations

Stephen F. Austin State University (SFASU) Department of Environmental Science has recently invested in a gas chromatograph which can be used to analyze air samples for volatile organic compounds (VOCs) such as benzene, toluene, ethylbenzene, and xylenes (BTEX). The goal of this project was to develop a standard operating procedure (SOP) and modify the current method for the detection of VOCs associated with oil and gas drilling activity to accommodate the equipment and capabilities of SFASU Environmental Assessment Lab. This study aims to provide the framework for future research in air quality monitoring in the Eagle Ford Shale area. An …

Free-Free Absorption In Hot Relativistic Flows: Application To Fast Radio Bursts, Esha Kundu, Bing Zhang

Physics & Astronomy Faculty Research

Magnetic flares create hot relativistic shocks outside the light cylinder radius of a magnetized star. Radio emission produced in such a shock or at a radius smaller than the shock undergoes free–free absorption while passing through the shocked medium. In this work, we demonstrate that this free–free absorption can lead to a negative drift in the frequency-time spectra. Whether it is related to the downward drift pattern observed in fast radio bursts (FRBs) is unclear. However, if the FRB down-drifting is due to this mechanism then it will be pronounced in those shocks that have isotropic kinetic energies ≳1044 erg. …

Catalytic Pyrolysis Of Lignin Model Compounds (Pyrocatechol, Guaiacol, Vanillic And Ferulic Acids) Over Nanoceria Catalyst For Biomass Conversion, Nataliia Nastasiienko, Tetiana Kulik, Borys Palianytsia, Julia Laskin, Tetiana Cherniavska, Mykola Kartel, Mats Larsson

Department of Chemistry Faculty Publications

Understanding the mechanisms of thermal transformations of model lignin compounds (MLC) over nanoscale catalysts is important for improving the technologic processes occurring in the pyrolytic conversion of lignocellulose biomass into biofuels and value-added chemicals. Herein, we investigate catalytic pyrolysis of MLC (pyrocatechol (P), guaiacol (G), ferulic (FA), and vanillic acids (VA)) over nanoceria using FT-IR spectroscopy, temperature-programmed desorption mass spectrometry (TPD MS), and thermogravimetric analysis (DTG/DTA/TG). FT-IR spectroscopic studies indicate that the active groups of aromatic rings of P, G, VA, and FA as well as carboxylate groups of VA and FA are involved in the interaction with nanoceria surface. …

Molten-Salt-Assisted Annealing For Making Colloidal Znga2o4:Cr Nanocrystals With High Persistent Luminescence, Bhupendra B. Srivastava, Santosh K. Gupta, Swati Mohan, Yuanbing Mao

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

Persistent luminescent nanocrystals (PLNCs) in the sub-10 nm domain are considered to be the most fascinating inventions in lighting technology owing to their excellent performance in anti-counterfeiting, luminous paints, bioimaging, security applications, etc. Further improvement of persistent luminescence (PersL) intensity and lifetime is needed to achieve the desired success of PLNCs while keeping the uniform sub-10 nm size. In this work, the concept of molten salt confinement to thermally anneal as-synthesized ZnGa2O4:Cr3+ (ZGOC) colloidal NCs (CNCs) in a molten salt medium at 650 °C is introduced. This method led to significantly monodispersed and few agglomerated NCs with a much improved …

The Role Of Hydrogen Bonding And Hydrogen Migration In Different Environments, Nassim Beiranvand

Chemistry Theses and Dissertations

Hydrogen bonding is one of the most important topics in chemistry and has been a subject of many studies for years, using both experimental techniques and computational methods. My dissertation focuses on mechanistic studies of various types of intermolecu-lar and intramolecular hydrogen bonding in di˙erent systems based on quantum chemical calculations. In my work, I investigated the interplay of ring puckering and hydrogen bonding in DNA building blocks; hydrogen bonding in natural and unnatural base pairs and the nature of dihydrogen bonding by applying the Ring Puckering Analysis and the Local Vibrational Mode Theory (LVM). An additional aim of my …

From Small Molecules To Infinite Crystals: Probing Noncovalent Interactions Through Vibrational Spectroscopy, Sadisha Nanayakkara

Chemistry Theses and Dissertations

During my four years in the CATCO group supervised by Dr. Kraka, I have been exposed to various topics targeted to address a multitude of chemical problems, broadening our knowledge of modern chemistry research as we know it. In undertaking the age-old problem of understanding the nature of chemical bonding, I could modestly contribute with my work, using in-house tools based on vibrational spectroscopy.

First part of my dissertation is focused on inventing new methods and tools to efficiently investigate chemical bonding, followed by the study of some non-covalent interactions, imperative in catalysis and solid-state chemistry. This includes analysis of …

A Proposed Change To Astronaut Exposures Limits Is A Giant Leap Backwards For Radiation Protection, Francis A. Cucinotta, Walter Schimmerling, Eleanor A. Blakely, Tom K. Hei

Health Physics and Diagnostic Sciences Faculty Research

Addressing the uncertainties in assessing health risks from cosmic ray heavy ions is a major scientific challenge recognized by many previous reports by the National Academy of Sciences (NAS) and the National Council on Radiation Protection and Measurements (NCRP) advising the National Aeronautics and Space Administration (NASA). These reports suggested a series of steps to pursue the scientific basis for space radiation protection, including the implementation of age and sex dependent risk assessments and exposure limits appropriate for a small population of radiation workers, the evaluation of uncertainties in risk projections, and developing a vigorous research program in heavy ion …

Tracking The Amide I And Αcoo− Terminal Ν(C=O) Raman Bands In A Family Of L-Glutamic Acid-Containing Peptide Fragments: A Raman And Dft Study, Ashley E. Williams, Nathan I. Hammer, Ryan C. Fortenberry, Dana N. Reinemann

Faculty and Student Publications

The E-hook of β-tubulin plays instrumental roles in cytoskeletal regulation and function. The last six C-terminal residues of the βII isotype, a peptide of amino acid sequence EGEDEA, extend from the microtubule surface and have eluded characterization with classic X-ray crystallographic techniques. The band position of the characteristic amide I vibration of small peptide fragments is heavily dependent on the length of the peptide chain, the extent of intramolecular hydrogen bonding, and the overall polarity of the fragment. The dependence of the E residue’s amide I ν(C=O) and the αCOO− terminal ν(C=O) bands on the neighboring side chain, the length …

Accessing Improbable Foldamer Shapes With Strained Macrocycles., Ko Urushibara, Yann Ferrand, Zhiwei Liu, Kosuke Katagiri, Masatoshi Kawahata, Estelle Morvan, Ryan D'Elia, Vojislava Pophristic, Aya Tanatani, Ivan Huc

College of Science & Mathematics Departmental Research

The alkylation of some secondary amide functions with a dimethoxybenzyl (DMB) group in oligomers of 8-amino-2-quinolinecarboxylic acid destabilizes the otherwise favored helical conformations, and allows for cyclization to take place. A cyclic hexamer and a cyclic heptamer were produced in this manner. After DMB removal, X-ray crystallography and NMR show that the macrocycles adopt strained conformations that would be improbable in noncyclic species. The high helix folding propensity of the main chain is partly expressed in these conformations, but it remains frustrated by macrocyclization. Despite being homomeric, the macrocycles possess inequivalent monomer units. Experimental and computational studies highlight specific fluxional …

Automated Parsing Of Flexible Molecular Systems Using Principal Component Analysis And K-Means Clustering Techniques, Matthew J. Nwerem

Computational and Data Sciences (MS) Theses

Computational investigation of molecular structures and reactions of biological and pharmaceutical interests remains a grand scientific challenge due to the size and conformational flexibility of these systems. The work requires parsing and analyzing thousands of conformations in each molecular state for meaningful chemical information and subjecting the ensemble to costly quantum chemical calculations. The current status quo typically involves a manual process where the investigator must look at each conformation, separating each into structural families. This process is time-intensive and tedious, making this process infeasible in some cases, and limiting the ability of theoreticians to study these systems. However, the …

Doping Of Conjugated Polymers: Preparation, Characterization And Device Fabrication, Kan Tang

Dissertations

Semiconducting conjugated polymers (CPs) as emerging materials for advanced electronic applications such as sensors, OPVs, and OEFTs has become an intriguing research topic in the past decades. It opens a new avenue of “flexible” electronics, which has shown great potential in next-generation electronic devices.

However, due to the nature of CP materials and related solution processing techniques, unlike almost perfectly crystalline silicon materials, CPs in the solid-state often exhibit much lower crystallinity if it is not complete amorphous, which severely hinder the electronic property and optical property of the materials. The crystallinity of CPs in a film is often uniquely …

Photopolymer Networks With Tunable Command Destruct Properties, William Walker

Dissertations

Photoinduced thiol-catalyzed hydrogen abstraction and beta-scission of acyclic benzylidene acetals is demonstrated as a new route to “command-destruct” polymer thermosets. Using this approach, we show that poly(thioether acetal) networks synthesized via thiol-ene photopolymerization rapidly degrade to alkyl benzoate byproducts when triggered with light, transitioning from solid to liquid within seconds. The light-driven construction and destruction processes, accessible via distinct differences in kinetics, are readily amendable for photopatterning, additive/subtractive manufacturing, and wavelength-selective applications.

The first chapter of this dissertation details the development of command-destruct poly(thioether acetal) networks via a previously unexplored mechanism for polymer degradation. The degradation mechanism is confirmed via …

College Of Natural Sciences Newsletter, August 2021, College Of Natural Sciences

College of Natural Sciences Newsletters and Reports

Volume 2, Issue 8.

Page 1 Dean's Message
Page 2 Awards and Recognition
Page 3 Student Summer Research
Page 4 Media Coverage of CNS
Page 5 Wintrode Student Success Center
Page 6-7 Welcome to our new Faculty & Staff!
Page 8 One Day for State: Thursday, Sept. 2nd
Page 7 Open PRAIRIE Data; Fall Faculty Retreat 2021

Crystal Structure Of 2-(2,6-Diisopropylphenyl)-N,Ndiethyl- 3,3-Dimethyl-2-Azaspiro[4.5]Decan-1- Amine: A Diethylamine Adduct Of A Cyclic(Alkyl)- (Amino)Carbene (Caac), Roxanne A. Naumann, Joseph W. Ziller, Allegra Liberman-Martin

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

The structure of the title compound, C₂₇H₄₆N₂, at 93 K has monoclinic (P2₁/n) symmetry. The title compound was prepared by treatment of 2-(2,6-diiso­propyl­phenyl)-3,3-dimethyl-2-aza­spiro­[4.5]dec-1-en-2-ium hydrogen dichloride with two equivalents of lithium di­ethyl­amide. Characterization of the title compound by single-crystal X-ray diffraction and ¹H and ¹³C NMR spectroscopy is presented. Formation of the di­ethyl­amine adduct of the cyclic(alk­yl)(amino)­carbene (CAAC) was unexpected, as deprotonation using lithium diiso­propyl­amide results in free CAAC formation.