Chemistry Commons^™

Interactive Comment On “Iodine Oxide In The Global Marine Boundary Layer” By C. Prados-Roman Et Al., Marcelo I. Guzman

Chemistry Faculty Publications

No abstract provided.

Crystal Structure Of 4,5-Bis-(3,4,5-Trimethoxyphenyl)-2H-1,2,3-Triazole Methanol Monosolvate, Nikhil Reddy Madadi, Narsimha Reddy Penthala, Shobanbabu Bommagani, Sean Parkin, Peter A. Crooks

Chemistry Faculty Publications

The title compound, C₂₀H₂₃N₃O₆·CH₃OH, was synthesized by [3 + 2] cyclo­addition of (Z)-2,3-bis­(3,4,5-tri­meth­oxy­phen­yl)acrylo­nitrile with sodium azide and ammonium chloride in DMF/water. The central nitro­gen of the triazole ring is protonated. The dihedral angles between the triazole ring and the 3,4,5-tri­meth­oxy­phenyl ring planes are 34.31 (4) and 45.03 (5)°, while that between the 3,4,5-tri­meth­oxy­phenyl rings is 51.87 (5)°. In the crystal, the mol­ecules, along with two methanol solvent mol­ecules are linked into an R ⁴ ₄(10) centrosymmetric dimer by N—H⋯O and O—H⋯N hydrogen bonds.

Crystal Structure Of (E)-13-{4-[(Z)-2-Cyano-2-(3,4,5-Trimethoxyphenyl)Ethenyl]Phenyl}Parthenolide Methanol Hemisolvate, Narsimha Reddy Penthala, Shobanbabu Bommagani, Venumadhav Janganati, Sean Parkin, Peter A. Crooks

Chemistry Faculty Publications

The title compound, C₃₃H₃₅NO₆ [systematic name: (Z)-3-(4-{(E)-[(E)-1a,5-dimethyl-9-oxo-2,3,7,7a-tetra­hydro­oxireno[2′,3′:9,10]cyclo­deca­[1,2-b]furan-8(1aH,6H,9H,10aH,10bH)-yl­idene]meth­yl}phen­yl)-2-(3,4,5-tri­meth­oxy­phen­yl)acrylo­ni­trile methanol hemisolvate], C₃₃H₃₅NO₆·0.5CH₃OH, was prepared by the reaction of (Z)-3-(4-iodo­phen­yl)-2-(3,4,5-tri­meth­oxy­phen­yl)acrylo­nitrile with parthenolide [systematic name: (E)-1a,5-dimethyl-8-methyl­ene-2,3,6,7,7a,8,10a,10b-octa­hy­dro­oxireno[2′,3′:9,10]cyclo­deca­[1,2-b]furan-9(1aH)-one] under Heck reaction conditions. The mol­ecule is built up from fused ten-, five- (lactone) and three-membered (epoxide) rings with a {4-[(Z)-2-cyano-2-(3,4,5-tri­meth­oxy­phen­yl)ethen­yl]phen­yl}methyl­idene group as a substituent. The 4-[(Z)-2-cyano-2-(3,4,5-tri­meth­oxy­phen­yl)ethen­yl]phenyl group on the parthenolide exocyclic double bond is …

Scalable Synthesis Of 5,11-Diethynylated Indeno[1,2-B]Fluorene-6,12-Diones And Exploration Of Their Solid State Packing, Bradley D. Rose, Peter J. Santa Maria, Aaron G. Fix, Chris L. Vonnegut, Lev N. Zakharov, Sean R. Parkin, Michael M. Haley

Chemistry Faculty Publications

We report a new synthetic route to 5,11-disubstituted indeno[1,2-b]fluorene-6,12-diones that is amenable to larger scale reactions, allowing for the preparation of gram amounts of material. With this new methodology, we explored the effects on crystal packing morphology for the indeno[1,2-b]fluorene-6,12-diones by varying the substituents on the silylethynyl groups.

Crystal Structure Of 1-Methoxy-2,2,2-Tris(Pyrazol-1-Yl)Ethane, Ganna Lyubartseva, Sean Parkin, Morgan D. Coleman, Uma Prasad Mallik

Chemistry Faculty Publications

The title compound, C₁₂H₁₄N₆O, consists of three pyrazole rings bound via nitro­gen to the distal ethane carbon of meth­oxy ethane. The dihedral angles between the three pyrazole rings are 67.62 (14), 73.74 (14), and 78.92 (12)°. In the crystal, mol­ecules are linked by bifurcated C—H,H⋯N hydrogen bonds, forming double-stranded chains along [001]. The chains are linked via C—H⋯O hydrogen bonds, forming a three-dimensional framework structure. The crystal was refined as a perfect (0.5:0.5) inversion twin.

Low-Temperature Phase Transitions In A Soluble Oligoacene And Their Effect On Device Performance And Stability, J. W. Ward, K. P. Goetz, A. Obaid, Marcia M. Payne, P. J. Diemer, C. S. Day, John E. Anthony, O. D. Jurchescu

Chemistry Faculty Publications

The use of organic semiconductors in high-performance organic field-effect transistors requires a thorough understanding of the effects that processing conditions, thermal, and bias-stress history have on device operation. Here, we evaluate the temperature dependence of the electrical properties of transistors fabricated with 2,8-difluoro-5,11-bis(triethylsilylethynyl)anthradithiophene, a material that has attracted much attention recently due to its exceptional electrical properties. We have discovered a phase transition at T = 205 K and discuss its implications on device performance and stability. We examined the impact of this low-temperature phase transition on the thermodynamic, electrical, and structural properties of both single crystals and thin films …

Low Voltage Electrowetting Device And Method For Making Same, Yuguang Cai, Xiaoning Zhang

Chemistry Faculty Patents

An electrowetting device includes a substrate having a first face, a charged adhesion layer immobilized on the first face of the substrate and a dielectric layer bound to the charged adhesion layer. An unbound ionic liquid phase contacts the dielectric layer.

Persistent Hepatic Structural Alterations Following Nanoceria Vascular Infusion In The Rat, Michael T. Tseng, Qiang Fu, Khoua Lor, G. Rafael Fernandez-Botran, Zhong-Bin Deng, Uschi M. Graham, D. Allan Butterfield, Eric A. Grulke, Robert A. Yokel

Chemistry Faculty Publications

Understanding the long-term effects and possible toxicity of nanoceria, a widely utilized commercial metal oxide, is of particular importance as it is poised for development as a therapeutic agent based on its autocatalytic redox behavior. We show here evidence of acute and subacute adverse hepatic responses, after a single infusion of an aqueous dispersion of 85 mg/kg, 30 nm nanoceria into Sprague Dawley rats. Light and electron microscopic evidence of avid uptake of nanoceria by Kupffer cells was detected as early as 1 hr after infusion. Biopersistent nanoceria stimulated cluster of differentiation 3⁺ lymphocyte proliferation that intermingled with nanoceria-containing …

Enhanced Charge Photogeneration Promoted By Crystallinity In Small-Molecule Donor-Acceptor Bulk Heterojunctions, Keshab Paudel, Brian Johnson, Mattson Thieme, Michael M. Haley, Marcia M. Payne, John E. Anthony, Oksana Ostroverkhova

Chemistry Faculty Publications

We examined sub-nanosecond time-scale charge carrier dynamics in crystalline films of a functionalized anthradithiophene (ADT) donor (D) with three different acceptor (A) molecules. A four-fold enhancement in ultrafast charge carrier separation efficiency was observed in D/A blends with a fullerene acceptor added at 7–10 wt. % concentrations, whereas a gradual decrease in peak photocurrent amplitude with acceptor concentration was observed with functionalized pentacene and indenofluorene acceptors. The results were directly correlated with the ADT-tri(ethylsilyl)ethynyl-F donor crystallinity. In the best-performing blends, the presence of crystalline acceptor domains was also established.

Co2 Reduction Under Periodic Illumination Of Zns, Ruixin Zhou, Marcelo I. Guzman

Chemistry Faculty Publications

The photoreduction of CO₂ to formate (HCOO^–) in sphalerite (ZnS) aqueous suspensions is systematically studied in the presence of Na₂S hole scavenger. A series of cut-on filters at λ_cut-on ≥ 280, 295, 305, 320, and 400 nm are used to measure the reaction rate of formate production. The dependence of the measured reaction rates on λ_cut-on indicates that a wavelength of λ = 345 nm is associated with the actual bandgap of the semiconductor nanocrystallites suspended in water. The results from apparent quantum yield measurements during periodic illumination experiments suggest that (1) valence-band …

Systems And Methods For Diagnosis And Monitoring Of Bacteria-Related Conditions, Sylvia Daunert, Sapna K. Deo, Patrizia Pacini, Anjali Kumari Struss, Harohalli Shashidhar, Deborah R. Auer Flomenhoft, Nilesh Raut

Chemistry Faculty Patents

The presently-disclosed subject matter provides systems, methods, and kits for diagnosing and/or monitoring a bacteria-related condition of interest in a subject by providing a cell sensing system, each system containing a reporter molecule capable of detecting binding of a quorum sensing molecule and capable of generating a detectable signal.

Functional Relevance Of Acrb Trimerization In Pump Assembly And Substrate Binding, Wei Lu, Meng Zhong, Qian Chai, Zhaoshuai Wang, Linliang Yu, Yinan Wei

Chemistry Faculty Publications

AcrB is a multidrug transporter in the inner membrane of Escherichia coli. It is an obligate homotrimer and forms a tripartite efflux complex with AcrA and TolC. AcrB is the engine of the efflux machinery and determines substrate specificity. Active efflux depends on several functional features including proton translocation across the inner membrane through a proton relay pathway in the transmembrane domain of AcrB; substrate binding and migration through the substrate translocation pathway; the interaction of AcrB with AcrA and TolC; and the formation of AcrB homotrimer. Here we investigated two aspects of the inter-correlation between these functional features, …

A Review Of Air–Ice Chemical And Physical Interactions (Aici): Liquids, Quasi-Liquids, And Solids In Snow, T. Bartels-Rausch, H. -W. Jacobi, T. F. Kahan, J. L. Thomas, E. S. Thomson, J. P. D. Abbatt, M. Ammann, J. R. Blackford, H. Bluhm, C. Boxe, F. Domine, M. M. Frey, I. Gladich, M. I. Guzmán, D. Heger, Th. Huthwelker, P. Klán, W. F. Kuhs, M. H. Kuo, S. Maus, S. G. Moussa, V. F. Mcneill, J. T. Newberg, J. B. C. Pettersson, M. Roeselová, J. R. Sodeau

Chemistry Faculty Publications

Snow in the environment acts as a host to rich chemistry and provides a matrix for physical exchange of contaminants within the ecosystem. The goal of this review is to summarise the current state of knowledge of physical processes and chemical reactivity in surface snow with relevance to polar regions. It focuses on a description of impurities in distinct compartments present in surface snow, such as snow crystals, grain boundaries, crystal surfaces, and liquid parts. It emphasises the microscopic description of the ice surface and its link with the environment. Distinct differences between the disordered air–ice interface, often termed quasi-liquid …

Soil And Biosolid Nano- And Macro-Colloid Properties And Contaminant Transport Behavior, Jessique L. Ghezzi

Theses and Dissertations--Plant and Soil Sciences

Despite indications that they are potential contaminant transport systems and threats to groundwater quality, very little effort has been invested in comparing contaminant transport behavior of natural environmental nanocolloids and their corresponding macrocolloid fractions in the presence of As, Se, Pb, and Cu contaminants. This study involved physico-chemical, mineralogical, stability and contaminant-transport characterizations of nano- (< 100 nm) and macro-colloids (100-2000 nm) fractionated from three Kentucky soils and one biosolid waste. Particle size was investigated with SEM/TEM and dynamic light scattering. Surface reactivity was estimated using CEC and zeta potential. Mineralogical composition was determined by XRD, FTIR, and thermogravimetric analyses. Sorption isotherms assessed affinities for Cu²⁺, Pb²⁺, AsO₃^-, and SeO₄^-2 contaminants, while settling kinetics experiments of suspensions at 0, 2 and 10 mg/L contaminants determined stability and transportability potential. Undisturbed 18x30 cm KY Ashton Loam soil monoliths were also used for …

Quantification Of Factors Governing Drug Release Kinetics From Nanoparticles: A Combined Experimental And Mechanistic Modeling Approach, Kyle Daniel Fugit

Theses and Dissertations--Pharmacy

Advancements in nanoparticle drug delivery of anticancer agents require mathematical models capable of predicting in vivo formulation performance from in vitro characterization studies. Such models must identify and incorporate the physicochemical properties of the therapeutic agent and nanoparticle driving in vivo drug release. This work identifies these factors for two nanoparticle formulations of anticancer agents using an approach which develops mechanistic mathematical models in conjunction with experimental studies.

A non-sink ultrafiltration method was developed to monitor liposomal release kinetics of the anticancer agent topotecan. Mathematical modeling allowed simultaneous determination of drug permeability and interfacial binding to the bilayer from release …

Monitoring The Influence Of Acid Deposition On Soil And Implications To Forest Health In The Daniel Boone National Forest, Tyler M. Sanderson

Theses and Dissertations--Forestry and Natural Resources

Combustion of fossil fuels has contributed to many environmental problems including acid deposition. The Clean Air Act (CAA) was created to reduce ecological problems by cutting emissions of sulfur and nitrogen. Reduced emissions and rainfall concentrations of acidic ions have been observed since the enactment of the CAA, but soils continue to receive some acid inputs. Soils sensitive to acid deposition have been found to have low pH, a loss of base cations and a shift in the mineral phase controlling the activity of Al³⁺ and/or SO₄^2-. If inputs continue, soil may be depleted of base …

Rat Hippocampal Responses Up To 90 Days After A Single Nanoceria Dose Extends A Hierarchical Oxidative Stress Model For Nanoparticle Toxicity, Sarita S. Hardas, Rukhsana Sultana, Govind Warrier, Mo Dan, Peng Wu, Eric A. Grulke, Michael T. Tseng, Jason M. Unrine, Uschi M. Graham, Robert A. Yokel, D. Allan Butterfield

Chemistry Faculty Publications

Ceria engineered nanomaterials (ENMs) have very promising commercial and therapeutic applications. Few reports address the effects of nanoceria in intact mammals, let alone long term exposure. This knowledge is essential to understand potential therapeutic applications of nanoceria in relation to its hazard assessment. The current study elucidates oxidative stress responses in the rat hippocampus 1 and 20 h, and 1, 7, 30 and 90 days following a single systemic infusion of 30 nm nanoceria. The results are incorporated into a previously described hierarchical oxidative stress (HOS) model. During the 1-20 h period, increases of the GSSG: GSH ratio and cytoprotective …

Electron And Ion Spectroscopy Of Metal Hydrocarbon Complexes, Sudesh Kumari

Theses and Dissertations--Chemistry

Metal-hydrocarbon complexes were prepared in a laser-vaporization molecular beam source and studied by single-photon zero electron kinetic energy (ZEKE) and mass-analyzed threshold ionization (MATI) spectroscopy. The ionization energies and vibrational frequencies of the metal complexes were measured from the ZEKE and MATI spectra. Metal-ligand bonding and low-lying electronic states of the neutral and ionized complexes were analyzed by combining the spectroscopic measurements with quantum chemical calculations and spectral simulations.

In this dissertation, the metal complexes of mesitylene, aniline, cyclooctatetraene, benzene, ethene, and propene were studied. For each complex, different effects from metal coordination have been identified. Although metal-bis(mesitylene) sandwich complexes …

Structures And Electronic States Of Small Group 3 Metal Clusters, Lu Wu

Theses and Dissertations--Chemistry

Group 3 metal clusters are synthesized by laser vaporization in a pulsed cluster beam source and identified with laser ionization time-of-flight mass spectrometry. The adiabatic ionization energies and vibrational frequencies of these clusters are measured using mass-analyzed threshold ionization (MATI) spectroscopy. Their structures and electronic states are determined by combining the MATI spectra with quantum chemical calculations and spectral simulations. This dissertation focuses on the study of several small molecules, which include LaO₂, La₂, M₂O₂, M₃O₄, M₃C₂, and La₃C₂O, where …

Electrode And Electrolyte Additives For Lifetime Extension In Lithium-Ion Batteries, Kishore Anand Narayana

Theses and Dissertations--Chemistry

Lithium-ion batteries (LIBs) are the most commonly used type of rechargeable batteries with a global market estimated at $11 billion, which is predicted to grow to $60 billion by 2020. The global commercialization of Li-ion batteries is impeded by issues such as poor cycle life (5000 cycles achieved in some LIBs) in high energy and power density applications because of the rising internal resistance due to aging and safety concerns such as overcharge which ultimately leads to thermal runaway and explosions. A battery’s performance mainly depends on external factors such as electrode thickness and degree of compacting, and the type …

A Study Of Lignin Depolymerization By Selective Cleavage Of The Cα-Cβ Linkages In Lignin Model Compounds Via Baeyer-Villiger Oxidation & An Investigation Of The Channeling Reaction In Nitrogen-Doped Multiwalled Carbon Nanotubes (N-Mwcnts), Nikhil Dilip Patil

Theses and Dissertations--Chemistry

A STUDY OF LIGNIN DEPOLYMERIZATION BY SELECTIVE CLEAVAGE OF THE Cα-Cβ LINKAGES IN LIGNIN MODEL COMPOUNDS VIA BAEYER-VILLIGER OXIDATION

Lignin is amorphous aromatic polymer derived from plants and is a potential source of fuels and bulk chemicals. Herein, we present a survey of reagents for selective stepwise oxidation of lignin model compounds. Specifically, we have targeted the oxidative cleavage of Cα-Cβ bonds as a means to depolymerize lignin and obtain useful aromatic compounds. In this work, we prepared several lignin model compounds that possess structures, characteristic reactivity, and linkages closely related to the parent lignin polymer. We observed that selective …

Cross Photoreaction Of Pyruvic And Glyoxylic Acids In Model Aqueous Aerosols, Shasha Xia

Theses and Dissertations--Chemistry

Aerosols affect climate change, the energy balance of the atmosphere, and public health due to their variable chemical composition, size, and shape. Aerosols from natural and anthropogenic sources can be primary organic aerosols (POA), which are directly emitted to the atmosphere, or secondary organic aerosols (SOA) that are formed from chemical reactions of gas-phase precursors. At variance with the well investigated formation of SOA from gas phase precursors, the chemistry of aqueous SOAs that contribute to the total SOA budget remains unknown. Field measurements have revealed that carboxylic, dicarboxylic and oxocarboxylic acids are abundant species present in SOAs. This thesis …

Salen Aluminum Compounds In The Dealkylation And Detection Of Organophosphates, Rahul R. Butala

Theses and Dissertations--Chemistry

The focus of this dissertation is the use of aluminum Schiff base compounds, Salen(^tBu)AlBr (SAB), in the dealkylation and detection of organophosphates (OPs). Three SAB compounds, Salen(^tBu)AlBr (1), Salpen(^tBu)AlBr (2), and Salophen(^tBu)AlBr (3) were used to dealkylate a variety of trialkyl OPs. These reactions lead to unique organic-soluble aluminum phosphate compounds containing six-coordinate aluminum. Examples include [salen(^tBu)AlOP(O)(OCH₃)₂]_n (4), [salen(^tBu)AlOP(O)(OCH₂CH₃)₂]_n (5), [salen(^tBu)AlOP(O)(OPh)₂]_{n …}

Methods Development In Biological Mass Spectrometry: Application In Glycoproteomics, Sanja Trajkovic

Theses and Dissertations--Chemistry

Proteomics refers to global characterization of the full set of proteins present in a biological sample. Various analytical disciplines contribute to proteomics but mass spectrometry became method of choice for analysis of complex protein samples.

Mass spectrometry allows for high throughput analysis of the proteome but, moreover, it has the ability to acquire higher-order information such as post-translational modifications (PTM). Glycosylation is the most abundant PTM on eukaryotic proteins.

This dissertation will focus on method development for structural proteomics that will be utilized to explain the glycoproteome of obligate intracellular protozoan parasite Toxoplasma gondii as a model system.

Optimization of …

Laser Spectroscopy Of Radicals Containing Group Iiia And Va Elements, Robert A. Grimminger

Theses and Dissertations--Chemistry

Radicals are interesting to study because of importance in so many processes such as semiconductor growth or stellar evolution. Laser induced fluorescence (LIF) and wavelength resolved emission spectra of jet cooled HPS, HAsO, AsD₂, H₂PS, and F₂BO have been measured using the pulsed discharge jet technique.

Several bands in the à ¹A′′ − X̃ ¹A′ transition of HPS were observed and assigned with the help of ab initio calculations. The ab initio geometries showed that HPS does not follow Walsh’s predictions for the angle change upon electronic excitation; Walsh predicts an increase …

Nuclear Structure In Transitional Regions: Studies Of ¹³²,¹³⁴Xe And Lifetimes In The Stable Zr Nuclei With The (N,N′Γ) Reaction, Erin Elizabeth Peters

Theses and Dissertations--Chemistry

Nuclei at closed shells tend to be spherical and are well-described by the shell model, while those between closed shells are deformed and better described by collective models. The nuclei which are in transitional regions between spherical and deformed may be studied to gain insight into the nature of this transition. The stable isotopes of zirconium and xenon span such transitional regions and are the subject of this dissertation. Gamma-ray spectroscopy following inelastic neutron scattering has been performed on the stable isotopes of Zr as well as ^132,134Xe at the University of Kentucky Accelerator Laboratory. Level lifetimes have been …

Applications Of Gas Chromatography/Mass Spectrometry And Capillary Electrophoresis For The Analysis Of Lignocellulosic Biomass Pretreatment, Dawn M. Kato

Theses and Dissertations--Chemistry

The focus of this dissertation centers on the development and applications of gas chromatography/mass spectrometry and capillary electrophoresis methodologies to quantify monomeric compositions of the β-O-4 linkages in lignin. Pretreatment is a required step in the utilization of lignocellulosic biomass for biofuels. Lignin is the target of pretreatment because it hinders the accessibility of enzymes and chemicals to cellulose. The effects of pretreatment are commonly assessed utilizing enzymatic saccharification and lignin assays. However, these techniques do not elucidate the effects of pretreatment on the monomeric make up of lignin.

The overarching hypothesis of this dissertation is that changes in individual …

Temperature-Dependent Tunable Photoluminescence Properties Of Carbon Nanodots Derived From Polyethylene Glycol, Sin Hea Yeom

Theses and Dissertations--Chemistry

Fluorescent carbon dots (C-dots) are well known for their low cell-cytotoxicity, biocompatibility, low preparation cost, excitation dependent photoluminescence, and excellent photostability. Typically, raw C-dots have low quantum efficiency and thus researchers have been utilizing biocompatible polymers such as polyethylene glycol (PEG) as a passivation agent in order to increase fluorescence signal. In this work, we report fluorescent self-passivated carbon nanodots (CNDs) synthesized from PEG by using it as a carbon source as well as a passivating agent. Importantly, the addition of graphene quantum dots (GQDs) during the synthesis of self-passivated CNDs can tune photoluminescence property. The results of bioimaging and …

Addressing Public Health Risks Of Persistent Pollutants Through Nutritional Modulation And Biomimetic Nanocomposite Remediation Platforms, Bradley J. Newsome

Theses and Dissertations--Chemistry

Due to their relative chemical stability and ubiquity in the environment, chlorinated organic contaminants such as polychlorinated biphenyls (PCBs) pose significant health risks and enduring remediation challenges. Engineered nanoparticles (NPs) provide a novel platform for sensing/remediation of these toxicants, in addition to the growing use of NPs in many industrial and biomedical applications, but there remains concern for their potential long-term health effects. Research highlighted herein also represents a transdisciplinary approach to address human health challenges associated with exposure to PCBs and NPs. The objectives of this dissertation research are two-fold, 1) to develop effective methods for capture/sensing and remediation …

Nicotine Exploits A Copi-Mediated Process For Chaperone-Mediated Up-Regulation Of Its Receptors, Brandon J. Henderson, Rahul Srinivasan, Weston A. Nichols, Crystal N. Dilworth, Diana F. Gutierrez, Elisha D. W. Mackey, Sheri Mckinney, Ryan M. Drenan, Christopher I. Richards, Henry A. Lester

Chemistry Faculty Publications

Chronic exposure to nicotine up-regulates high sensitivity nicotinic acetylcholine receptors (nAChRs) in the brain. This up-regulation partially underlies addiction and may also contribute to protection against Parkinson's disease. nAChRs containing the α6 subunit (α6* nAChRs) are expressed in neurons in several brain regions, but comparatively little is known about the effect of chronic nicotine on these nAChRs. We report here that nicotine up-regulates α6* nAChRs in several mouse brain regions (substantia nigra pars compacta, ventral tegmental area, medial habenula, and superior colliculus) and in neuroblastoma 2a cells. We present evidence that a coat protein complex I (COPI)-mediated process mediates this …