Physical Sciences and Mathematics Commons^™

A Study Of 3-Tropylium-1,5-Hexadiene, Elise Noma Hattersley

Dissertations, Theses, and Masters Projects

No abstract provided.

The Analysis Of Plasmid Conformers Using Dynamic Size-Sieving Capillary Electrophoresis, Stacey Nevins

Dissertations, Theses, and Masters Projects

No abstract provided.

Exo- And Endo-Tricarbonyl[(4b,5,6,7,8,8a-Η)-Cis-N-Methyl-2,3,4,4a,9,9a-Hexahydro-1h- Carbazole]Chromium(0), Nigam Rath, F. Pigge, Shiyue Fang

Chemistry & Biochemistry Faculty Works

Acid-mediated hydride reduction of tricarbonyl([eta]6-N-methyl-1,2,3,4-tetrahydrocarbazole)chromium(0) affords either the cis-fused exo-hexahydrocarbazole chromium(0) complex {[Cr(C13H17N)(CO)3], (I)} exclusively, or a separable mixture of (I) and the endo-isomer {[Cr(C13H17N)(CO)3], (II)}, depending upon the choice of hydride donor. The conformations of the hexahydrocarbazole systems differ in the orientation of the indoline moiety with respect to the saturated hexahydrocarbazole rings. The isolation of the exo isomer is unusual, as this complex arises via reaction at the sterically more hindered endo face of the coordinated ligand.

Generation Of Intense Excimer Radiation From High-Pressure Hollow Cathode Discharges, Ahmed El-Habachi, Karl H. Schoenbach

Bioelectrics Publications

By reducing the diameter of the cathode opening in a hollow cathode discharge geometry to values on the order of 100 μm, we were able to operate these discharges in noble gases in a direct current mode up to atmospheric pressure. High-pressure discharges in xenon were found to be strong sources of excimer radiation. Highest intensities at a wavelength of 172 nm were obtained at a pressure of 400 Torr. At this pressure, the vacuum ultraviolet (VUV) radiant power of a single discharge operating at a forward voltage of 220 V and currents exceeding 2 mA reaches values between 6% …

Novel Synthetic Route To 5-Substituted Indoles, Helen Y. Chen

Master's Theses

No abstract provided.

Removal Of Water-Soluble Cationic Dyes With Trisyl Silicas, Erdener Karadağ, Dursun Saraydin, Fatma Aydin

Turkish Journal of Chemistry

In this study, the adsorption of certain water-soluble cationic dyes, (basic blue 9, basic blue 12, basic blue 17, brilliant cresyl blue, janus green B, basic green 4, basic violet 1, basic violet 3, and thionin) onto TriSyl silicas by batch adsorption at 25^oC was investigated. In the adsorption experiments, Langmuir type adsorption in the Giles classification system was found. Binding parameters such as the initial binding constant (K$_i$), the equilibrium binding constant (K), monolayer coverage(n), site-size(u), maximum fractional occupancy ($\hat{\theta}$), and the thermodynamic parameter free energy of adsorption $(\Delta G)$ were calculated for TriSyl silica and cationic dye systems …

Electroanalysis Using Differential Pulse Methods At A Microelectrode, Enda Howard, John Cassidy, John O'Gorman

Articles

This communication characterises the differential pulse voltammetric response of ultramicroelectrodes in connection with two different models

Preparation For Sci-Tech Librarianship: Results Of A Survey, John Sandy, Mary Frances Lembo, James Manasco

Sci-Tech News

No abstract provided.

Bioremediation Of Soil Contaminated With Explosives, Catherine A. Axtell

Dissertations and Theses @ UNI

Bioremediation of contaminated soil and water has been the topic of considerable research interest. White rot fungi have recently been proposed for use in biodegradation of explosives. The explosives, TNT, RDX and HMX are integral components of the manufacture of munitions. The wastes from the production of these and other explosives have been discharged into the surrounding environment resulting in contamination. Phanerochaete chrysosporium and strain F600, a proprietary white rot fungus developed by Mycotech Corporation, were studied with regard to their ability to degrade TNT, HMX and RDX in liquid cultures and in soil. Laboratory studies demonstrated that P. chrysosporium …

Paramagnetic Nuclear Magnetic Resonance (Nmr) Studies On The Calcium Binding Site Of [Alpha]-Lactalbumin, Thomas Kurt Ritter

Dissertations and Theses

Paramagnetic NMR has drawn interest as a technique for extending the range of systems that can be investigated. The purpose of this study was to determine whether a combination of paramagnetic two-dimensional and relaxation techniques allows for assigning resonances corresponding to residues forming the metal binding site of proteins in which the metal is coordinated exclusively by amino acid side chains and which have been previously inaccessible to assignment.

α-Lactalbumin (LA) is a calcium binding protein with relatively broad NMR signals; this broadness has prevented complete assignment. LA has been the subject of many studies, because it can form a …

Xanthones As Antimalarial Agents : Binding Interactions Between Heme Analogues And Xanthones, Jane Xu Kelly

Dissertations and Theses

Human falciparum malaria is caused by Plasmodium falciparum parasite, which digests host hemoglobin within its food vacuole, releasing toxic heme. P. falciparum detoxifies free heme to hemozoin by polymerization. This process is believed to be the target of most successful antimalarial drugs, chloroquine and quinine, which are now losing their effectiveness due to the spread of multi-drug resistant strains. Xanthones were recognized in the laboratory of Dr. M. Riscoe (Portland VA Medical Center) to bind to heme, preventing heme polymerization [Ignatushchenko, M., Winter R., and Riscoe, M. (1997) FEBS Letters 409, 67].

This thesis reports a study of the interactions …

The Synthesis And Characterization Of A Porphyrin Oligomer As A Potential Antenna For Light Harvesting Solar Cells, Tristan Timothy Jenkins

Dissertations and Theses

Mankind's attempts to harvest the sun have resulted in photocells with about 15% overall energy conversion efficiency. The best of these cells consist of a light-sensitive dye attached to a semiconductor. Absorbed light energy is transferred to the semiconductor via the delivery of an excited electron from the dye. Dye electrons are replenished with a redox solution, coupling the dye to the counter electrode.

This research was the beginning of an exploration into some potential improvements in the cell. First of all, the redox solution is a corrosive liquid, and leaks present a problem. A porphyrin oligomer with a TCPP …

Pyrrolic Compounds, Michael J. Therien, Stephen Dimagno

Chemistry Department: Faculty Publications

Novel methylpyrroles are provided, as well as processes for their preparation.

Photoinduced Coupling Of Acetylenes And Quinone In The Solid State As Preorganized Donor−Acceptor Pairs, E. Bosch, S. M. Hubig, Sergey V. Lindeman, Jay K. Kochi

Chemistry Faculty Research and Publications

Crystalline electron donor−acceptor (EDA) complexes of various diarylacetylenes (DA) and dichlorobenzoquinone (DB) are isolated and structurally characterized by X-ray crystallography. Deliberate excitation of either the DB acceptor at λ_DB = 355 nm or the 1:2 [DA, 2DB] complex at λ_CT = 532 nm in the solid state leads to [2 + 2] cycloaddition and identical (isomeric) mixtures of the quinone methide products. Time-resolved (ps) diffuse reflectance spectroscopy identifies the ion-radical pair [DA^•+, DB^•-] as the reactive intermediate derived by photoinduced electron transfer in both photochemical …

Intrinsic Semiconducting Materials On Phthalocyanine Basis, Michael Hanack

Turkish Journal of Chemistry

Stacked transition metal macrocycles [MacM(L)]$_n$ with M e.g. Fe, Ru, Os, Co, Rh and Mac = phthalocyanine (Pc) 1,2- or 2,3-naphthalocyanine (1,2-, 2,3-Nc) were synthesized. The bridging ligands (L) may be e.g. pyrazine (pyz) or $s$-tetrazine (tz). In general, these complexes [MacM(L)]$_n$ are insoluble in organic solvents; however, soluble oligomers [R$_4$PcM(L)]$_n$ can be prepared using metallomacrocycles R$_n$PcM, R = $t$-bu, et, OR, M = Fe, Ru, which are substituted in the peripheric positions. A systematic investigation of the influence of the bridging ligands on the semiconducting properties in [MacM(L)]$_n$ reveals that changing L, e.g., from dabco over pyz to tz …

Phthalocyanines And Related Compounds: Subunits For The Preparation Of Molecular Materials, J. Garcia, A. Gonzalez, A. Gouloumis, E.M. Maya, M.D. Perez, B.D. Rey, P. Vazquez, T. Torres

Turkish Journal of Chemistry

The design, synthesis, structural and physical characterization and engineering, and the study of the electrical conductivity and the nonlinear optical properties of phthalocyanines and molecular substances related to them, such as subphthalocyanines, hemiporphyrazines and triazolephthalocyanines were reviewed.

Azobenzene Side-Chain Liquid Crystalline Polyesters With Outstanding Optical Storage Properties, S. Hvilsted, M. Pedersen, N.C.R. Holme, P.S. Ramanujan

Turkish Journal of Chemistry

A flexible azobenzene side-chain liquid crystalline (SCLC) polyester architecture employed for reversible optical storage is described. The modular design allows four structural parameters to be individually modified. These parameters: {\em i}- the methylene side-chain spacer length, {\em ii}- the substituent on azobenzene, {\em iii}- the methylene main-chain segment length, and {\em iv}- the polyester molecular mass, all influence the optical storage properties. A general synthetic route to novel mesogenic azobenzene diols comprising parameters {\em i} and {\em ii} is outlined. Polyesters with molecular masses (parameter {\em iv}) up to 100,000 are routinely obtained by melt transesterification of the novel diols …

Electropolymerization Of Thiophene With And Without Aniline In Acetonitrile, Muzaffer Can, Kadir Pekmez, Nuran Pekmez, Attila Yildiz

Turkish Journal of Chemistry

The electrooxidation behaviors of thiophene and 3-methylthiophene on a Pt surface in acetonitrile/tetrabutylammonium tetrafluoroborate solution were investigated using cyclic voltammetry. The electropolymerization of these monomers and electrochemical properties of polythiophene and poly(3-methylthiophene) were studied in neutral, acidic and basic media. Mechanisms related to the formation of polymers and electroactivity loss were proposed. The effect of thiophene on the electropreparation and properties of polyaniline were also investigated. The presence of thiophene in solutions of aniline in acetonitrile accelerates the formation and causes an improvement in the conductivity of polyaniline films. Thiophene, which catalyzes the polyaniline formation, enters into the structure of …

Electrochromism Of Sol-Gel Derived Niobium Oxide Films, M. Maçek, B. Orel

Turkish Journal of Chemistry

Niobium oxide films are promising cathodic electrochromics that in many aspects can compete with the more frequently studied WO$_3$ films. The films reported herein were prepared using the sol-gel route from a NbCl$_5$ precursor. The electrochromic properties were pronounced for crystalline films that are heat-treated at 500^oC and exhibited transmittance changes between coloured and bleached states of 60 \% in the UV and 80 \% in the VIS-NIR regions. Improved bleaching and more reversible electrochromism of thick niobium oxide films (d $>$ 250 nm) were obtained by lithiation.

Electrically Conductive Polymer Grafts Prepared By Electrochemical Polymerization Of Pyrrole Onto Poly[(Methyl Methacrylate)-Co-(2-(N-Pyrrolyl) Ethyl Methacrylate)] Electrodes, Nuran Balci, Ural Akbulut, Levent Toppare, Dietmar Stanke, Manfred L. Hallensleben

Turkish Journal of Chemistry

Pyrrole was grafted on poly[(methyl methacrylate)-co-(2-(N-pyrrolyl) ethyl methacrylate)] (PMMA-co-PEMA) using constant potential electrolyses. The thermal stability of PMMA-co-PEMA was improved as a result of electrochemical grafting with pyrrole. The electrochemical behavior of the films was studied by cyclic voltammetry. Pyrrole was found to be electroactive on PMMA-co-PEMA electrodes.

Dc Conduction In Electrochemically Synthesized Polypyrrole Films, Akif Kaynak

Turkish Journal of Chemistry

DC conductivity measurements were performed by modified four-probe rig on electrochemically synthesized polypyrrole films at a temperature range of -30^oC to 120^oC. Conductivity increased with temperature. The temperature dependence of conductivity was very high for lightly doped polymers, decreasing as the doping level increased. The model used to describe the conduction process was the conduction model originally developed for amorphous silicon by Mott and Davis. When applied to conducting polymers, it assumes that electron transport originates from localized or fixed states within the polymer chain. The charge transfer between the chains takes place by hopping, referred to as phonon-assisted hopping, …

Dimerization Of Pyrrole, Mine Yurtsever, Ersin Yurtsever

Turkish Journal of Chemistry

Accurate ab-inito quantum mechanical calculations of pyrrole dimers are reported. The thermodynamical stabilities of dimers with $\alpha - \alpha, \alpha - \beta$, and $\beta - \beta$ type linkages are compared in order to predict the possibilities of branching in polypyrroles. Calculations employing large basis sets and including electron correlation effects predict the $\alpha - \alpha$ dimers as the most stable form. However, an $\alpha - \beta$ type bonding requires only 1.5-2.0 kcal/mol, and the energy necessary to introduce a $\beta - \beta$ type bond is 3.6-4.0 kcal/mol. These values show that a high degree of branching is possible even at …

Electrocatalytic Properties Of Platinum Doped Polyaniline And Polypyrrole Electrodes, F. Kadirgan, F. Fiçicioğlu, İ. Beceri̇k

Turkish Journal of Chemistry

This review paper aims to show how the electrochemical behaviour of polyaniline (PANI) and polypyrrole (PPy) electrodes modified by platinum help to improve the oxidation of organic molecules such as methanol, ethylene glycol and glucose. Although the amount of platinum deposited was very small, i.e., 0.1 mg.cm$^{-2}$, the catalytic activity obtained was comparable to bulk platinum. Another notable point is the reduction of the poisoning effect, which is the main problem faced in the electrooxidation of organic molecules for fuel cell applications.

Heat Treatment Of Maceral Groups Obtained From Turkish Bituminous Coals, Elif Sultan Vayi̇soğlu, Nevin Gaye Erbatur

Turkish Journal of Chemistry

The dilatation properties of parent coals and their maceral fractions were examined. In all the coal samples, the main petrographic constituent was the vitrinite maceral. Reflectance of the vitrinite and inertinite macerals increased after carbonization, while the liptinite maceral disappeared and caused large pores in the vitrinite macerals. All of the coals developed anisotropic coke.

Heme Transfer Reactions: An Important Prerequisite For Synthetic Oxygen Carriers, Jan Paul, Wenhua Chen, Per-Ingvar Ohlsson, Michael Smith

Turkish Journal of Chemistry

Electronic changes of iron- and metal free porphyrins are reviewed in light of their importance to modify the ferri/ferro reduction potential and energy dissipation between ligated carbon monoxide and the porphyrin chelate. Substitutions at positions 2 and 4 are effective ways to exercise this influence. Other measures include exposure to water and modifications of axial ligation, including the \lq three-ligand' case. These measures will also influence the stability of recombined hemin-protein entities, as apparent from the kinetics of heme-transfer from a modified donor protein to apomyoglobin, but the stability appears to be related to the bulkiness of 2,4-substitutional groups rather …

The Amido And Bisalkoxo-Complexes Of [Tri(3,5-Dimethylpyrazolyl)Borato]Molydenum Nitrosyl, Işıl Topaloğlu

Turkish Journal of Chemistry

In this study, the amido nitrosyl molybdenum complex, [Mo{HM(3,5-Me_2C_3HN_2)_3}(NO)Cl(NH_2)], was prepared. This compound reacts with alocohols, yielding the bisalkoxo complexes, [Mo{HM (3,5-Me_2C_3HN_2)_3}(NO)(OR)_{2}] (R = Me, Et, Pr^n, Bu^n). The new complexes were analyzed by IR and ^1H-NMR spectroscopy.

Thermodynamic Studies Of Some Complexes Of 2-Benzoylpyridine 4-Phenyl-3-Thiosemicarbazone, T. Atalay, E. Güler Akgemci̇

Turkish Journal of Chemistry

The stability constants of the Co(II), Ni(II), Cu(II) and Zn(II) complexes with 2-benzoylpyridine 4-phenyl-3-thiosemicarbazone were determined using a spectrophotometric method at different temperatures (25, 30, 35 and 40 $\pm$ 0.1^oC) and ionic strengths (0.05, 0.01 and 0.20 M KNO$_3$) in 50 \% (v/v) aqueous ethanol. Plots of thermodynamic stability constants at zero ionic strength ($\ln$ K^o) versus T$^{-1}$ gave linear curves and $\Delta$ H^o and $\Delta$ S^o were also calculated from these plots. Moreover, the changes in free energy for each metal-ligand system were calculated from the following equation. $\Delta$ G^o = -RT $\ln$ K^o.

The Adsorption Isotherms Of The Bleaching Of Sun Ower-Seed Oil, Hüseyin Topallar

Turkish Journal of Chemistry

In this study, the absorbance measurements were taken for the bleaching of sunflower-seed oil with wt. 0.3, 0.5, 0.7 and 0.9 % of clay at 60, 70, 80 and 90°C. Bentonite EY-09 was used as the bleaching clay. Since the heat evolved during adsorption (0.33-1.07 kJ mol^{-1}) was less than 20 kJ mol^{-1}, the forces between the adsorbent and adsorbate appear to be van der Waals forces, and this type of adsorption is physical or van der Waals adsorption. Thus, it was seen that the Freundlich equation was more applicable than the Langmuir equation to the experimental adsorption isotherms for …

Recovery Of Copper, Cobalt, Nickel, Cadmium, Zinc And Bismuth From Electrolytic Copper Solution, Fırat Aydin, Ömer Yavuz, Berrin Zi̇yadanoğullari, Recep Zi̇yadanoğullari

Turkish Journal of Chemistry

An electrolytic Copper Solution (ECS) was electrolyzed using platinum electrodes. Copper was obtained in solid form. In order to precipitate Cd(II), Bi(III), As(III), Sb(III) and the rest of the Cu(II) ions, H_2S gas was passed through the remaining solution. The remaining solution was evaporated to obtain metal sulphates. The sample containing metal sulphates was roasted at temperatures between 550 and 800°C. Cobalt, nickel and zinc in the solid sample remained in the form of metal sulphates, while the iron in the sample was converted into Fe_2O_3. This solid sample was dissolved in water and filtered in order to crystallize the …

Polymerization Of Pyrrole And Thiophene On Polyethylene Adipate Electrodes, Seyfettin Erturan, Burcu Yalvaç, Sena Toraman

Turkish Journal of Chemistry

Polymerizations of pyrrole and thiophene on a platinum foil coated by polyethylene adipate (PEA) were carried out in acetonitrile by electrochemical methods. Different compositions of semi-conducting composite films of PEA/Polypyrrole(PPy), PEA/Polythiophene(PT) were prepared by the electrochemical polymerization of pyrrole and thiophene on PEA electrode. The polymerization was possible only for a certain thickness of the polyethylene adipate(PEA) on the platinum. Conductivities of PEA/PPy, PEA/PT, films at different compositions were obtained. The films were examined by FTIR spectroscopy. The topography of surface films were analyzed by a scanning electron microscope(SEM). The conductivity behaviour of (PEA/PPy), (PEA/PT) films at different compositions when …