Chemistry Commons^™

The First Potential Energy Surfaces For The C₆Hˉ-H₂ And C₆Hˉ-He Collisional Systems And Their Corresponding Inelastic Cross Sections, Kyle M. Walker, Fabien Dumouchel, François Lique, Richard Dawes

Chemistry Faculty Research & Creative Works

Molecular anions have recently been detected in the interstellar and circumstellar media. Accurate modeling of their abundance requires calculations of collisional data with the most abundant species that are usually He atoms and H₂ molecules. In this paper, we focus on the collisional excitation of the first observed molecular anion, C₆H^-, by He and H₂. Theoretical calculations of collisional cross sections rely generally on ab initio interaction potential energy surfaces (PESs). Hence, we present here the first PESs for the C₆H^--H₂ and C₆H^--He van …

Gas Phase Structure Characterization Using Fourier Transform Ion Cyclotron Resonance Mass Spectrometry, Anupriya Anupriya

Theses and Dissertations

This dissertation investigates Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS) based techniques to study the impact of molecular structure on conformation and binding energetics. A novel method to determine collison cross sectional areas using FTICR (CRAFTI), initially developed by the Dearden lab, was applied to study the conformations of molecular systems with unique structural attributes in an attempt to explore the molecular range of CRAFTI. The systems chosen for CRAFTI studies include crown-ether alkylammonium complexes and biogenic amino acids. The results were found to be consistent with expected behavior, and strongly correlated with experimental measurements made using ion mobility …

Analysis Of Improvised Explosives By Electrospray Ionization - Mass Spectrometry And Microfluidic Techniques, Inge Corbin

FIU Electronic Theses and Dissertations

Improvised explosives may be based on smokeless gunpowder, fertilizers, or inorganic oxidizers such as nitrate (NO3-), chlorate (ClO3-), and perchlorate (ClO4-) salts.

Identification is a priority for the military and law enforcement but due to their varying physical properties and complexity, identification can be challenging. Consequently, three methods have been developed to aid in presumptive and confirmatory detection.

Smokeless powder contains plasticizers, stabilizers, dyes, opacifiers, flash suppressants, and other compounds. Identification of these additives can narrow down or identify the brands of smokeless powder used in a device. Fourteen organic smokeless powder components were identified by capillary electrochromatography (CEC) using …

Resonance Raman Studies Of Oxygenated Forms Of Myoglobin And Cyp2b4 And Their Mutants, Ying Wang

Dissertations (1934 -)

Important oxidative heme enzymes use hydrogen peroxide or activate molecular oxygen to generate highly reactive peroxo-, hydroperoxo- and feryl intermediates resulting from heterolytic O-O bond cleavage. Members of the cytochrome P450 superfamily catalyze difficult chemical transformations, including hydroxylations and C-C bond cleavage reactions. In mammals, these enzymes function to reliably produce important steroids with the required high degree of structural precision. On the other hand, certain other mammalian P450s serve a different role, efficiently metabolizing xenobiotics, including pharmaceuticals and environmental pollutants. Though so important, the precise mechanisms involved in such transformations are incompletely understood, because of difficulties in structurally characterizing …

Multiplexed Detection Of Double-Stranded Pathogenic Dna With Engineered Zinc Finger Proteins, Juhwa Kim

Masters Theses & Specialist Projects

The development of a new technology for the detection of doublestranded (ds) DNA enables multiple biomedical applications including identifying multiple pathogens simultaneously. We previously employed colorimetric SEquence-Enabled Reassembly with TEM-1 β-lacatamase (SEER-LAC) to detect specific bacterial DNA sequence. SEER-Lac consists of the two inactive β-lactamase fragments which of each attached to a zinc finger protein (ZFP) would reassemble into an active full-length enzyme upon ZFPs binding to its target DNA. Here, we engineered two pairs of ZFPs which of each recognizes shiga toxin in E. coli O157 and staphylococcal enterotoxin B in Staphylococus Aureus, respectively. Biotin was simply conjugated to …

Low-Cost Quartz Crystal Microbalance System Platform Designed For Chemical Nanoparticle, Danming Wei

Masters Theses & Specialist Projects

QCM sensor is a response to a kind of broad spectrum, high sensitivity, and simple structure, low-cost detection device, and particularly its quality as a type of gas sensor is widely used. With the successful oscillation in liquid phase, QCM sensor has been involved in the application analytical chemistry, surface chemistry, biochemistry and environmental monitoring side and many other scientific fields. With sensitive surface film as the sensitive element, AT-cut quartz crystal as energy transducer components by changes of the relationship between mass of surface film and frequency of QCM sensor transduces signals of mass or concentration into output frequency …

Synthetic Investigation On The Biomimetic Metal-Catalyzed Sulfoxidations And Photochemical Generation Of A Highly Reactive Ruthenium(V)-Oxo Porphyrin, Weilong Luo

Masters Theses & Specialist Projects

Catalytic oxidation plays a crucial role in current chemical and pharmaceutical industries which is also a leading technology for green chemical processes. In Nature, the ubiquitous cytochrome P450 enzymes can catalyze a wide variety of oxidation reactions with high efficiency and selectivity. Many transition metal catalysts are designed as the biomimetic model of cytochrome P450 enzymes. In this work, series of metalloporphyrins and metallocorroles have been successfully synthesized to investigate and develop catalytic selective oxidation of sulfides to sulfoxides.

Manganese(III) porphyrin complexes (2) and manganese(III) corrole complexes (6) with iodobenzene diacetate [PhI(OAc)2] as a mild oxygen source exhibited remarkable catalytic …

Role Of Ros And Rns Sources In Physiological And Pathological Conditions, Sergio Di Meo, Tanea Reed, Paola Venditti, Victor Manuel Victor

EKU Faculty and Staff Scholarship

There is significant evidence that, in living systems, free radicals and other reactive oxygen and nitrogen species play a double role, because they can cause oxidative damage and tissue dysfunction and serve as molecular signals activating stress responses that are beneficial to the organism. Mitochondria have been thought to both play a major role in tissue oxidative damage and dysfunction and provide protection against excessive tissue dysfunction through several mechanisms, including stimulation of opening of permeability transition pores. Until recently, the functional significance of ROS sources different from mitochondria has received lesser attention. However, the most recent data, besides confirming …

Predictive Coupled-Cluster Isomer Orderings For Some SiNCM (M, N ≤ 12) Clusters: A Pragmatic Comparison Between Dft And Complete Basis Limit Coupled-Cluster Benchmarks, Jason N. Byrd, Jesse J. Lutz, Duminda S. Ranasinghe, Yifan Jin, Ajith Perera, Xiaofeng F. Duan, Larry W. Burggraf, John A. Montgomery Jr.

Faculty Publications

The accurate determination of the preferred Si₁₂C₁₂ isomer is important to guide experimental efforts directed towards synthesizing SiC nano-wires and related polymer structures which are anticipated to be highly efficient exciton materials for opto-electronic devices. In order to definitively identify preferred isomeric structures for silicon carbon nano-clusters, highly accurate geometries, energies and harmonic zero point energies have been computed using coupled-cluster theory with systematic extrapolation to the complete basis limit for set of silicon carbon clusters ranging in size from SiC₃ to Si₁₂C₁₂. It is found that post-MBPT(2) correlation energy plays a …

Probing The Effects Of Nano-Domains On The Redox Products In Molecular Solvents-Rtils Mixtures, Abderrahman Atifi

Dissertations (1934 -)

Room temperature ionic liquids (RTIL) have been very attractive as replacements for molecular solvents (MS) in many areas in chemistry. The use of the RTIL in mixture with MS as reaction media will reduce the cost and viscosity of RTILs. The formation of RTIL nano-domains (nano-structures) in the mixture may lead to partitioning of solutes between the MS and the RTIL phase, where the properties and reactivity would be more like those in pure ionic liquids. In the present work, analytical approaches have been employed to probe the presence and effects of RTIL nano-domains on redox processes in the mixture. …

Computational Studies Of Alkane C-H Functionalization By Main-Group Metals, Samantha Jane Gustafson

Theses and Dissertations

The most efficient homogeneous catalysts for hydroxylation of light alkanes utilize transition metals in superacid solvent and operate by tandem electrophilic C-H activation/metal-alkyl (M-R) functionalization. An emerging alternative strategy to transition metals is the use of high-oxidation state main-group metals (e.g. TlIII, PbIV, IIII) that hydroxylate light alkanes. This dissertation reports density-functional theory calculations that reveal the mechanisms, reactivity, and selectivity of TlIII promoted alkane C-H functionalization in trifluoroacetic acid and TlIII-dialkyl functionalization in water. Calculations reveal that TlIII oxidizes alkanes via a closed-shell C-H activation and M-R functionalization mechanism that is similar to transition-metal C-H functionalization mechanisms. Comparison of …

Computational Studies On Mechanisms And Reactivity Of Mercury And Cobalt Organometallic Reactions, Jack Terrell Fuller

Theses and Dissertations

Density Functional Theory (DFT) is a powerful tool for treating large organometallic structures efficiently and accurately. DFT calculations on the Hg-catalyzed oxidation of methane to methyl bisulfate in sulfuric acid suggest the lowest energy pathway involves a closed-shell electrophilic C–H activation mechanism coupled with metal alkyl reductive functionalization and oxidation by SO3. Comparison to Tl, Zn, and Cd suggests that Hg is unique in its ability to catalyze this set of reaction steps. Comparison to K2S2O8 highlights the selectivity of this C–H activation reaction as opposed to radical conditions. In contrast, DFT calculations indicate that CoIII(TFA)3 oxidizes methane through a …

Synthesis And Biological Evaluation Of Small Molecule Inhibitors Of Bmpr1b, Paulo Andre Machicao Tello

Theses and Dissertations

Methods for preparing an array of potential small molecule inhibitors of Bone Morphogenetic Protein Receptor 1b (BMPR1b) are described. Target molecules were prepared from two general classes: (1) N9-aryl-N6-ureidoadenines, and (2) dicarbamyl iodoacetamides. Recent data from the Peterson lab indicated that both classes might bind to BMPR1b and thus inhibit this key receptor. Docking studies performed using Sureflex Dock suggested the N9-aryl-N6-ureidoadenines would bind to the active site of BMPR1b. In addition antiproliferative activities of dicarbamyl iodoacetamides previously synthesized in the Peterson lab pointed to this moiety as an attractive target for structure activity relationship (SAR) development. Compounds were prepared …

Studies Toward Yaku'amide A And Synthesis And Applications Of Bulky Α,Β-Dehydroamino Acids, Jintao Jiang

Theses and Dissertations

Yaku'amide A shows a unique inhibitory profile against a series of 39 human cancer cell lines (JFCR39). In our efforts to synthesize yaku'amide A, we have optimized our regioselective base-free aminohydroxylation method with a series of nitrogen sources, developed a chiral reagent-mediated aminohydroxylation strategy and chemoselective deprotections of the resulting aminohydroxylation product, and explored a stereospecific E2 dehydration and O-N acyl transfer sequence. In addition, we have prepared the right-hand tetrapeptide and the NTA subunit. For our bulky α,β-dehydroamino acids project, we have developed strategies to incorporate α,β-dehydroamino acids such as ΔVal and ΔEnv into small synthetic peptides via Solid …

Synthesis And Applications Of Lanthanide Sulfides And Oxides, Christopher Marin

Department of Chemistry: Dissertations, Theses, and Student Research

This dissertation focuses on two of the key fields where lanthanides find ready application: as optically active materials with a focus on the lanthanide sulfides, and as catalytic materials with a focus on cerium oxide.

The lanthanide sulfides have attracted considerable interest for their potential as solar energy conversion materials, pigments, infrared window materials, and phosphor host media. However, applications of these materials remain limited due to their synthetic difficulty along with their not well understood properties compounded by both their difficulty in manufacturing as well as in simulating largely due to the need to take into account f-shell electrons. …

Electrogenerated Chemiluminescence Of Luminophores And Enhancement With Melatonin, Sarah Michelle Roughton

MSU Graduate Theses

The photoluminescent (PL), electrochemical, and electrogenerated chemiluminescent (ECL) properties of 1,5-I-Aedans (N-(iodoacetylaminotheyl)-1-naphthylamine-5-sulfonic acid) in aqueous buffered (KH2PO4) and 50:50 (v/v) acetonitrile:KH2PO4 solutions were obtained. Tri-n-propylamine (TPrA) was used as the oxidative-reductive coreactant. The PL efficiencies (em) were 1.83 in KH2PO4 and 4.81 in mixed solvent compared to Ru(bpy)32+ standard solutions (em = 1.0). 1,5-I-Aedans displayed quasi-reversible oxidative electrochemistry in aqueous solutions and irreversible to quasi-reversible oxidation in mixed solvent. ECL efficiencies (ecl) were obtained by comparison to a Ru(bpy)32+/TPrA (bpy = 2,2'-bipyridine) standard (ecl = 1) and were higher in KH2PO4 (ecl = 6.8 x 10-4) than in the mixed …

Possible Sources And Impacts Of Biochar Water Extractable Organic Compounds On Aquatic Microorganisms, Cameron Russell Smith

Chemistry & Biochemistry Theses & Dissertations

Smokeless biomass pyrolysis with application of biochar as a soil amendment could be a significant approach for carbon sequestration to possibly control climate change for energy and environmental sustainability. If biochar were to be utilized as a soil amendment and a carbon sequestration agent at Gt C scales, the release of potentially toxic compounds into soils and associated hydrological systems, through soil rainwater runoff and leaching, might have negative consequences, in both agro-ecosystems and aquatic environmental systems. Therefore, the main focus of this dissertation was to study the sources and chemical composition of biochar water extractable (soluble) organic compounds and …

Discoloration Of A Green Pigment In Tintoretto’S Allegorical Figure Of Spring And Analysis Of The Chemical Properties And Stability Of Copper Resinate, Sarah Wells Conner Horn

Chemistry & Biochemistry Theses & Dissertations

The focus of this thesis is the discoloration of a common historical green pigment, copper resinate. In this research the discoloration was investigated in Jacopo Tintoretto’s painting, Allegorical Figure of Spring, painted c. 1555. This painting is believed to have been painted with copper resinate which has discolored to brown over the centuries. The state of repair of the painting was determined using visual analysis under visible and UV light and the use of copper green pigments was confirmed using energy-dispersive X-ray fluorescence, including copper resinate based upon supplementary historical evidence. Substantial evidence was found from visual inspection and …

Student Identification Of Problem Topics In General Chemistry, Michelle Denyse Hilda Herridge

MSU Graduate Theses

Eliciting students' beliefs regarding the difficulty of subject matter is important since self-efficacy often determines study habits. The goal of this research was to investigate students' perceptions about the relative difficulty of topics taught in tertiary-level introductory chemistry courses. As a proof of concept, I created a survey composed of topics adapted from the South Carolina high school chemistry standards. This survey was piloted at Clemson University, where general chemistry students at the end of their first-semester were asked to rank the topics by perceived level of difficulty. Based on the pilot data analysis the survey was revised, adapted and, …

Insight Into The Inhibition Of Ribonucleotide Reductases By 2'-Chloro-2'-Deoxynucleotides And 2'-Azido-2'-Deoxynucleotides: Biomimetic Studies With Model Substrates, Mukesh M. Mudgal Dr.

FIU Electronic Theses and Dissertations

Ribonucleotide Reductases (RNRs) are crucial enzymes that catalyze reduction of ribonucleotides to deoxyribonucleotides, required for the biosynthesis of DNA. Vital role played by RNR in the biosynthesis of DNA and its control on cell growth made it one of the main targets for anticancer therapy. Several laboratories clarified the aspects of reaction cascades at active site of RNR. Biochemical studies of RNR by Stubbe for the inactivation of RDPR by 2'-chloro-2'-deoxyuridine-5'-diphosphate emphasizes departure of chlorine as an anion, while biomimetic studies by Robins with 6'-O-nitro-2'-chloro-homonucleosides emphasizes the elimination of chlorine substituent from 2'-position as a radical. To clarify …