Digital Commons Network^™

A Computational Approach To Determining Stability Constants For Transition Metal Ion Complexes, Jason St. Clair

Honors Theses

The complexation of metal ions in natural waters plays a critical role in defining the metal's biogeochemistry, Numerous investigators have used various experimental techniques to measure complexation constants in the laboratory, but many constants are still poorly undefined or have yet to be investigated due to the difficulty of some of the experiments. A computational approach to obtaining these constants for complexes of Fe(lII), Fe(D), Cr(lli), Cu(lI), Zn(II), and Cd(II) was explored with varying degrees of success. Calculated Gibbs Free Energies were compared to experimental stability constants. Calculations were performed using Spartan's DFT package at the pEP level and with …

Cisplatin Interstrand Cross-Linking Of Defined Sequence Nucleosomal Dna, Erin Elizabeth Wilkes

Honors Theses

DNA interstrand cross-linking agents have been recognized for many years to be powerful antitumor chemotherapeutics. While the interactions between free DNA and many anticancer drugs have been explored extensively, there is less infonnation available about these interactions with nucleosomal DNA. Nitrogen mustards have been reported to exhibit relatively similar cross-linking sites and efficiencies of binding in free and nucleosomal DNA, but mitomycin C exhibits markedly reduced cross-linking near the center of nucleosomal DNA. This current study focuses on cisplatin interstrand cross-linking of the 154 base pair 55 rRNA gene fragment of Xenopus borealis reconstituted with histones from chicken erythrocytes. The …

A Catechol Approach To Natural Product Synthesis, Michelle E. Weber

Honors Theses

This research has focused on the total synthesis of the iron--chelating natural product 1-(2,3-hydroxyphenyl)-4-methoxy-I-butanone. An extract of the iron-cleficient fungus Gleophyllwn lraebeum, this molecule is thought to bind to Fe3+ in a hexacoordinate system to aid in transport through cell walls in order to help regulate iron levels in such iron-deficient fungi. Since the proposed structure of the molecule is based only on the spectral data of a very small sample, our hope is to synthesize and confirm its structure as the extract of the brown rot fungus. We have developed a relatively short retrosynthesis for our work on this …

Interactions Of Ti(Iv) And Sn(Iv) Organometallic Complexes With Double-Stranded Dna, Katherine Macdonald Davies

Honors Theses

In order to understand further the interactions that exist between specific organometallic complexes and DNA, reactions of double-stranded calf-thymus DNA with bis(cyclopentadienyl)titanium dichloride [Cp₂TiC1₂] (TDC), bis(t-butylcyclopentadienyl)titanium dichloride [(C₄H₉Cp)₂TiC1₂] (r-butyl TDC), bis(i-propylcyclopentadienly)titanium dichloride [(C₃H₆Cp)2TiCl₂ a-propyl mc), bis(pentamethylcyclopentadienyl) titanium dichloride [(Cp"₂TiC1₂ (pentarnethyl TDC), triphenyltin chloride (Ph₃SnCl), diphenylrin dichloride (Ph₂SnC1₂) , and triphenyltin acetate (Ph₃SnOAc) were performed. The goal of this research is to establish how the fundamental structure and composition of these compounds determine the effecti veness of their DNA interactions. Each metal compound was incubated with calf thymus DNA at several metal: DNA ratios and reactions were maintained at 37°C at …

Studies On The Methylation Of 5-Nitro-Benzimidazoles, Mashooda Hasan, Farzana Shaheen, Uzma Yunus

Turkish Journal of Chemistry

Methylation of 2H, 5-nitro- (1) and 2-ethyl, 5-nitro- (2) benzimidazoles separately with methyl iodide in acetone in the presence of potassium carbonate yielded 2H, 5/6-nitro-(3A and 3B) and 2-ethyl, 5/6-nitro- (4A and 4B) methylbenzimidazoles respectively. Methylation of 1 and 2 in dimethylformamide in place of acetone yielded not only 3A, 3B and 4A, 4B respectively, but in addition 1,3-dimethyl-5-nitro-benzimidazol-2-one (5) was also obtained in each case. The structure of the synthesized compounds was determined with the help of mass and ^1H NMR spectroscopic analysis.

Specific Determination Of Hydrogen Peroxide With A Catalase Biosensor Based On Mercury Thin Film Electrodes, F. Ni̇l Ertaş, Suna Ti̇mur, Erol Akyilmaz, Erhan Di̇nçkaya

Turkish Journal of Chemistry

A biosensor for specific determination of hydrogen peroxide was developed using catalase (EC 1.11.1.6) in combination with a mercury film electrode. Catalase was immobilized with gelatine by means of glutaraldehyde on the electrode surface. The biosensor response was monitored by following the reduction peak of dissolved oxygen at around -0.24 V. The peak current changes upon addition of hydrogen peroxide and gives a linear response in a concentration range of 1-50 x 10^{-6} M within a response time of 3 minutes.

Spectrophotometric Determination Of Selenium (Iv) Using Methdilazine Hydrochloride, Mahaveer B. Melwanki, Jaldappa Seetharamappa

Turkish Journal of Chemistry

Methdilazine hydrochloride is proposed as a selective and sensitive reagent for the spectrophotometric determination of selenium (IV). The reagent forms a red radical cation by selenimum (IV) in hydrochloric acid medium and exhibits an absorption maximum at 513 nm. Beer's law is valid over the concentration range 0.1-2.3 mg1^{-1} of selenium (IV). Sandell's sensitivity of the reaction is found to be 3.57 ng cm^{-2} and the molar extinction coefficient is 9.32 x 10^4 1 mol^{-1} cm^{-1} at 513 nm. The effects of acidity, reagent concentration, temperature and diverse ions upon the absorbance of the red species are critically assessed. The …

A Convenient Synthesis Of Some 4-(Alkylamino)-4,5-Dihydro-1h-1,2,4-Triazol-5-Ones, Bahi̇tti̇n Kahveci̇, Aykut İki̇zler

Turkish Journal of Chemistry

A series of 3-alkyl-4-(arylidenamino)-4,5-dihydro-1H-1,2,4-triazol-5-ones, {\bfseries 6-10,} was obtained from the reaction of the corresponding 3-alkyl-4-amino-4,5-dihydro-1H-1,2,4-triazol-5-ones, {\bfseries 1,} with the appropriate aldehydes. 3-alkyl-4-(alkylamino)-4,5-dihydro-1H-1,2,4-triazol-5-ones of type {\bfseries 11-16} were synthesized from the selective reduction of compounds {\bfseries 5-10} with NaBH$_{4}$ in diglyme or DMSO medium as a general and convenient method.

Ion-Selective Membrane Electrode For The Determination Of A Novel Phenylpiperazine Antidepressant, Nefazodone, Arzum Erdem, Di̇lşat Özkan, Kağan Kerman, Burcu Meri̇ç, Tayfun Dalbasti, Mehmet Özsöz

Turkish Journal of Chemistry

The construction and performance characteristics of ion-selective membrane electrodes for a newly found phenylpiperazine antidepressant, Nefazodone (NFN), based on its ion-pair complexes with phosphotungstate (PT), tetraphenylborate (TPB), tungstosilicate (TS) and reineckate (RN) in a poly(vinyl chloride) (PVC) matrix are described. The best ion-selective electrode for determination of NFN contains NFN-PT as the active material. This electrode exhibits a Nernstian response (62.6 ± 0.4 mV per decade) in the range 1.5 x 10$^{-5}$ to 1.0 x 10^{-2} M NFN.HCl in solutions. The selectivity of this electrode to NFN in the presence of a number of sugar molecules, cations and drugs is …

Chemical Oxidation Of Mtbe Under O2-Rich And O2-Limited Environments Coupled With Biological Degradation Of Oxidation Byproducts, J. Sutherland, B. Panka, Craig D. Adams, Joel Gerard Burken

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The H2O2/UV Advanced Oxidation Process (AOP) Was Investigated to Determine Byproduct Formation under Different Experimental Conditions (PH, Alkalinity, and H2O2/UV Dose). a Key Factor in the Efficiency of the AOP Was the Dissolved Oxygen Concentration. Gas Chromatography/mass Spectrometry (GC/MS) Analysis Was Used to Identify Byproducts Resulting from Oxidation under Oxygen-Rich and Oxygen-Limited Conditions. Resultant Oxidation Byproducts Were Analyzed for their Susceptibility to Biological Degradation. Biodegradation Rate Constants Were Determined and Modeled for the Primary Byproducts of the Advanced Oxidation Process. Inhibition Resulting from the Presence of Multiple Byproducts in a Biological System Was Investigated as Well. Effects of Process Parameters …

Computerised Evaluation Of Cognitive And Motor Function, B. Kisačanin, G. C. Agarwal, J. Taber, D. (Daniel) Hier

Chemistry Faculty Research & Creative Works

In This Paper, We Present a Clinical Study of Computerized Tracking in the Evaluation of Cognitive and Motor Function. We Investigate its Use in the Assessment of Effectiveness of Antiepileptic Drugs (AEDs) as Well as in the Process of Following the Progress of Alzheimer's Disease (AD). to Simplify the Experiments, We Introduce Real-Time Adaptation of the Target Speed. in the Study with Epileptic Patients, Three Result Groups Are Compared: Blood Levels of AEDs, Scores on Standard Neuropsychological Tests, and Scores on Computerized Tracking and Reaction Time Tests. It is Found that the Computerized Tests Are Repeatable, Reliable and Sensitive and …

Theories Of The Origin And Early Evolution Of Life, David A. Dewitt

Faculty Publications and Presentations

After the theory of spontaneous generation was discredited, only religious explanations were offered to explain the origin of life. Alexander Oparin (1894-1980), an atheist, suggested that natural chemical reactions produced biological molecules that came together to form the first living thing. Later, Stanley Miller tested this hypothesis and produced chemical "building blocks" but not life itself. In spite of much progress, there is still no clear consensus on how life originated on Earth. Some scientists are even looking to outer space for the origin of life.

Activation Of P38 Mitogen-Activated Protein Kinase And C-Jun Nh2-Terminal Kinase By Double-Stranded Rna And Encephalomyocarditis Virus: Involvement Of Rnase L, Protein Kinase R, And Alternative Pathways, Mihail S. Iordanov, Jayashree M. Paranjape, Aimin Zhou, John Wong, Bryan R.G. Williams, Eliane F. Meurs, Robert H. Silverman, Bruce E. Magun

Chemistry Faculty Publications

Double-stranded RNA (dsRNA) accumulates in virus-infected mammalian cells and signals the activation of host defense pathways of the interferon system. We describe here a novel form of dsRNA-triggered signaling that leads to the stimulation of the p38 mitogen-activated protein kinase (p38 MAPK) and the c-Jun NH2-terminal kinase (JNK) and of their respective activators MKK3/6 and SEK1/MKK4. The dsRNA-dependent signaling to p38 MAPK was largely intact in cells lacking both RNase L and the dsRNA-activated protein kinase (PKR), i.e., the two best-characterized mediators of dsRNA-triggered antiviral responses. In contrast, activation of both MKK4 and JNK by dsRNA was greatly reduced in …

Parameters Influencing Sediments Resuspension And The Link To Sorption Of Inorganic Compounds, Eid A. Alkhatib, Keith Castor

Chemistry & Physics Faculty Publications

In the aquatic environment, the accumulation of chemicalcontaminants by sediments poses a potential threat to endemiclife forms and drinking water resources. Trace metals such asCd, Cu, Cr, Ni, Pb, and toxic organic compounds, are among awide variety of contaminants having an affinity for sediments.In this study, experiments were performed simulating sedimentresuspension in the lower Housatonic River, Connecticut, using aParticle Entrainment Simulator. Analyses of grain sizedistributions, porosities and total organic contents of thesediments suggested that these parameters influence theredistribution and entrainment of settleable solids in the watercolumn. These findings were established by evaluating the impactof one parameter on sediment resuspension as …

Enantiomeric High-Performance Liquid Chromatographic Separation Of Β- Substituted Tryptophan Analogues, G. Török, A. Péter, E. Vékes, J. Sápi, M. Laronze, J. Y. Laronze, Daniel W. Armstrong

Chemistry Faculty Research & Creative Works

The high-performance liquid chromatographic enantioresolution of β- substituted tryptophan analogues by direct and indirect methods is reported. The direct separation was carried out on chiral crown ether-bonded, on the macrocyclic antibiotic teicoplanin-bonded or on different derivatized β- cyclodextrin-bonded phases. The indirect resolution was achieved by applying pre-column derivatization with the chiral reagents 1-fluoro-2,4- dinitrophenyl-5-L-alanine amide (FDAA) and 2,3,4,6-tetra-O-acetyl-β-D- glucopyranosyl isothiocyanate (GITC). In the separation of all four isomers of the analytes, the indirect methods seemed to be more efficient than the direct methods. In most cases, the FDAA derivatives of the stereoisomers could be separated with better selectivity in methanol-containing …

Reaction Of Alpine-Borane With Aldehydes: Reactivity Rate Assessment By Observation Of The Disappearance Of The Carbonyl N - Pi* Peak By Uv-Visible Spectroscopy, Layla Bland, Michael J. Panigot

Journal of the Arkansas Academy of Science

Due to an unexpectedly difficult reduction of indole-3-carbaldehyde and of isobutyraldehyde using the chiral reducing agent Alpine-Borane, the reactivity of several aliphatic, aromatic, and unsaturated aldehydes was investigated. This was done in order to determine whether there was a relationship between aldehyde structure and reduction rate. It was found that aliphatic aldehydes and aromatic aldehydes with no strongly electron-donating groups on the arene ring reduced faster than unsaturated aldehydes.

3-Hydroxykynurenine And 3-Hydroxyanthranilic Acid Generate Hydrogen Peroxide And Promote Α-Crystallin Cross Linking By Metal Ion Reduction, Lee E. Goldstein, Michael C. Leopold, Xudong Huang, Craig S. Atwood, Aleister J. Saunders, Mariana Hartshorn, James T. Lim, Et Al.

Chemistry Faculty Publications

The kynurenine pathway catabolite 3-hydroxykynurenine (3HK) and redox-active metals such as copper and iron are implicated in cataractogenesis. Here we investigate the reaction of kynurenine pathway catabolites with copper and iron, as well as interactions with the major lenticular structural proteins, the R-crystallins. The o-aminophenol kynurenine catabolites 3HK and 3-hydroxyanthranilic acid (3HAA) reduced Cu(II)>Fe(III) to Cu(I) and Fe(II), respectively, whereas quinolinic acid and the nonphenolic kynurenine catabolites kynurenine and anthranilic acid did not reduce either metal. Both 3HK and 3HAA generated superoxide and hydrogen peroxide in a copper-dependent manner. In addition, 3HK and 3HAA fostered copper-dependent R-crystallin cross-linking. 3HK- …

Stereoselective Synthesis Of Butenolide And Butyrolactone Derivatives, Abdulkadi̇r Sirit

Turkish Journal of Chemistry

Optically active butenolide and $\gamma$-butyrolactone derivatives were prepared by removing (R)-phenyl glycinol and (1R, 2R)-norpseudoephedrine used as chiral auxiliaries from butenolides and \gamma-butyrolactones in two steps. The structures of these products were determined using ^1H NMR, ^{13}C NMR, Mass spect., IR and microanalysis.

Determination Of Nizatidine-Guest Complexation Constants And Computer Aided Molecular Design, Carolyn J. Mordas

Honors Theses

Nizatidine, N-[2-[[[2-[(dimethylamino)methyl]-4-thiazoly]]methy1]thio]ethyl]-N'- methyl- 2-nitro-I,l, ethenediamine, has been investigated for its potential to act as a host to small molecules through hydrogen bonding and pi-pi interactions. In previous work, pyridoxine (vitamin B6) was hypothesized to have a high guest-host binding constant with nizatidine. This was supported through experimental methods involving one and two dimensional NMR spectroscopy, UV-visible spectroscopy, and high performance liquid chromatography. Computer aided molecular design and three dimensional conformationally flexible database searching led to the discovery of other possible guests, including albuterol, which has exhibited even higher binding constants from HPLC.

A Time Resolved Laser Spectroscopy Study Of Resonance Energy Transfer Between Tb(Iii) And An Organic Dye: 6-Hydroxy-5-[(2-Methoxy-5-Methyl-4-Sulfophenyl)Azo]-2-Naphthalenesulfonic Acid Disodium Salt, Ronald Wesley Tennis

Masters Theses

Intermolecular energy transfer is a process of crucial importance to photochemistry and photophysics. Complexed lanthanide ions are well suited as energy transfer donors because they display dependable absorption and luminescence qualities with narrow rare-earthion emission in addition to relatively long excited-state lifetimes.

This project used a pulsed nitrogen laser and high speed digital techniques to study energy transfer dynamics between excited state Tb(acac)₃ and an ionic organic dye called Red 40. Luminescence decay profiles of excited terbium atoms in the presence of the quencher were measured in both high and low viscosity solvents. The effects of solvent viscosity and …

On The Stabilizing Action Of Protein Denaturants: Acetonitrile Effect On Stability Of Lysozyme In Aqueous Solutions, Evgenii L. Kovrigin, Sergey A. Potekhin

Chemistry Faculty Research and Publications

Stability of hen lysozyme in the presence of acetonitrile (MeCN) at different pH values of the medium was studied by scanning microcalorimetry with a special emphasis on determination of reliable values of the denaturational heat capacity change. It was found that the temperature of denaturation decreases on addition of MeCN. However, the free energy extrapolation showed that below room temperature the thermodynamic stability increases at low concentrations of MeCN in spite of the general destabilizing effect at higher concentrations and temperatures. Charge-induced contribution to this stabilization was shown to be negligible (no pH-dependence was found); therefore, the most probable cause …

Photodecomposition Of Crystal Violet Dye In Water Solution And Suspensions Of Metal Oxides, Tatiana Yurievna Zakharian

Dissertations and Theses @ UNI

Photodecomposition and photodecolorization of crystal violet dye were studied in water solution, hydrogen peroxide solution and suspensions of metal oxides. Spectroscopic evidence for the formation of methylated pararosanilines and demethylated derivatives of Michler's ketone as the reaction intermediates was obtained for the photodecomposition of crystal violet in water solution. The mechanism of formation of the intermediates was discussed in terms of charges of individual atoms calculated using Spartan software.

Photooxidation of crystal violet was shown to occur faster in hydrogen peroxide solution due to the higher oxidation potential of hydrogen peroxide and hydroxyl radicals. A mechanism similar to photooxidation in …

Cu(Ii) Potentiation Of Alzheimer A Neurotoxicity, Xudong Huang, Math P. Cuajungco, Craig S. Atwood, Mariana A. Hartshorn, Joel D. A. Tyndall, Graeme R. Hanson, Karen C. Stokes, Michael C. Leopold, Et Al.

Chemistry Faculty Publications

Oxidative stress markers as well as high concentrations of copper are found in the vicinity of Aβ amyloid deposits in Alzheimer's disease. The neurotoxicity of Aβ in cell culture has been linked to H2O2generation by an unknown mechanism. We now report that Cu(II) markedly potentiates the neurotoxicity exhibited by Aβ in cell culture. The potentiation of toxicity is greatest for Aβ1–42 > Aβ1–40 ≫ mouse/rat Aβ1–40, corresponding to their relative capacities to reduce Cu(II) to Cu(I), form H2O2 in cell-free assays and to exhibit amyloid pathology. The copper complex of Aβ1–42 has a highly positive formal reduction potential (≈+500–550 mV versus …

Emissions Of Formaldehyde, Acetic Acid, Methanol, And Other Trace Gases From Biomass Fires In North Carolina Measured By Airborne Fourier Transform Infrared Spectroscopy, Robert J. Yokelson, Jon G. Goode, Darold E. Ward, Ronald A. Susott, Ronald E. Babbitt, D. D. Wade, Issac T. Bertschi, David W. T. Griffith, Wei Min Hao

Chemistry and Biochemistry Faculty Publications

Biomass burning is an important source of many trace gases in the global troposphere. We have constructed an airborne trace gas measurement system consisting of a Fourier transform infrared spectrometer (FTIR) coupled to a “flow-through” multipass cell (AFTIR) and installed it on a U.S. Department of Agriculture Forest Service King Air B-90. The first measurements with the new system were conducted in North Carolina during April 1997 on large, isolated biomass fire plumes. Simultaneous measurements included Global Positioning System (GPS); airborne sonde; particle light scattering, CO, and CO₂; and integrated filter and canister samples. AFTIR spectra acquired within …

Enantioseparation Of Alkylaryl Sulfoxides Using Capillary Zone Electrophoresis, Chad Snyder

Masters Theses & Specialist Projects

Alkylaryl sulfoxides possess a chiral sulfur atom easily identifiable by capillary zone electrophoresis (CZE). Separation of chiral alkylaryl sulfoxides has already been accomplished by modified method of CZE known as micellar electrokinetic chromatography (MEKC). However, no articles have been published on the enantioseparation of alkylaryl sulfoxides using capillary zone electrophoresis.

A series of sulfoxides were synthesized, purified and identified via NMR. Enantioseparation was performed using CZE employing a 10 mmol. Phosphate buffer (pH 4.0, 25% acetonitrile, 2% sulfated-β-cyclodextrin). Synthesis of these sulfoxides will be presented along with the results of the procedure’s optimization. Separation of the sulfoxide enanitomers relies on …

Alkyl Nitrates During The Prophet ’98 Summer Intensive, Kristi A. Ostling

Masters Theses

As part of the PROPHET intensive held at the University of Michigan Biological Station in northern Michigan, a gas chromatography system for making fast-turnaround measurements of C1 to C5 alkyl nitrates was developed and deployed from July 19 to August 21, 1998. Every 30 minutes, samples were automatically acquired on a small Tenax trap made from silicosteel column and injected on a GC column by thermal desorption prior to ECD detection. Tests performed to measure breakthrough and on-trap destruction indicated no breakthrough for C3, C4, and C5 nitrates and excellent stability for these compounds on the trap. Chromatographic resolution of …

Cationic 5,10,15,20-Tetrakis(N-Methylpyridinium-4-Yl)Porphyrin Fully Intercalates At 5‘-Cg-3‘ Steps Of Duplex Dna In Solution, Anton B. Guliaev, Neocles B. Leontis

Chemistry Faculty Publications

The interaction of 5,10,15,20-tetrakis(N-methylpyridinium-4-yl)p (T4MPyP⁴⁺ with the oligonucleotide DNA duplex [d(GCACGTGC)](2) was studied by two-dimensional ¹H NMR spectroscopy, optical absorbance, circular dichroism, and molecular dynamics simulation employing particle mesh Ewald methods. T4MPyP⁴⁺ is one of the largest aromatic molecules for which intercalative binding to DNA has been proposed, although this has been called into question by recent X-ray crystallographic work [Lipscomb et al. (1996) Biochemistry 35, 2818-2823]. T4MPyP⁴⁺ binding to [d(GCACGTGC)]₂ produced a single set of (mostly) upfield-shifted DNA resonances in slow exchange with the resonances of the free DNA. Intra- and intermolecular NOEs …

Macrocyclic Antibiotics As Separation Agents, Daniel W. Armstrong

Chemistry Faculty Research & Creative Works

Macrocyclic antibiotics having ring structures with at least 10 members act as separation agents in crystallization, precipitation, filtration, electrophoresis and chromatography. The macrocyclic antibiotics include ansamacrolides, macrolides, macrocyclic peptides, polyenes and derivatives thereof. The process has been found to be especially advantageous for separation of optical isomers by electrophoresis and chromatography.

Humic Substances As Interferences In The Analysis Of Nitrite In Water, Stephanie Ann Tebault

Chemistry & Biochemistry Theses & Dissertations

Humic substances are of current interest because of their roles in environmental processes involving pollutants. It is also becoming recognized that humic substances may interfere in analysis of environmental samples though the possible adverse effects do not appear to be fully appreciated. The present effort focuses on determining whether humic materials interfere in the analysis of nitrite in water using the Griess reaction. This is a well-known reaction using nitrosation to gjve a diazonium salt followed by coupling with an appropriate reagent to form a dye. This colorimetric method continues to be applied in the laboratory and the field for …

Enantioselective Synthesis Of Dual Serotonergic Azanoradamantane Sc-52491, Daniel Becker, Robert K. Husa, Alan E. Moormann, Clara I. Villamil

Chemistry: Faculty Publications and Other Works

A racemic synthesis of azanoradamantane (±)-3 was accomplished via Yamamoto's MAD-catalyzed Diels-Alder protocol. Subsequently, a scalable asymmetric synthesis of azanoradamantane benzamide SC-52491 was carried out employing Helmchen's asymmetric Diels-Alder methodology to construct all four contiguous asymmetric centers with the correct relative stereochemistry and in 99.3% e.e.