Physical Sciences and Mathematics Commons^™

Preparation Of Optically Active Amino Acid Derivatives Of Some Methylated 5-Amino-Azaheterocycles, Mashooda Hasan, Farzana Shaheen, Uzma Yunus, Shazia Munir

Turkish Journal of Chemistry

The present paper describes the reduction of 1-methyl-5-nitro-benzimidazoles ({\bf 1A, 2A}) and 1,3-dimethyl-2H-5-nitro-benzimidazol-2-one ({\bf 3}) to 5-aminobenzimidazoles ({\bf 4A, 5A}) and 1,3-dimethyl-2H-5-amino-benzimidazol-2-one ({\bf 6}) respectively with hydrazine hydrate in absolute ethanol in the presence of graphite. Compounds {\bf 5A} and {\bf 6} were converted to 2-ethyl-5-(phthaloyl-L-phenylalanyl)amino-1-methylbenzimidazole ({\bf 7}) and 1,3-dimethyl-5-(phthaloyl-L-phenylalanyl)aminobenzimidazol-2-one ({\bf 8}). Characterization of the synthesized compounds was done with the help of mass spectrometry and ^1H NMR spectroscopic studies. Optical activity of the amino acid derivatives {\bf 7} and {\bf 8} was also recorded.

Flavonol Glycosides From Consolida Armeniaca, Mustafa Küçüki̇slamoğlu, Nuretti̇n Yayli, Hasan Basri̇ Şentürk, Hasan Genç, Seçki̇n Özden

Turkish Journal of Chemistry

Three known flavonol glycosides, i.e., kaempferol 3,7-O-\( \alpha \)-L-dirhamnopyranoside ({\bfseries 1}), kaempferol 3-O-\( \beta \)-D-glucopyranosyl-(1\( \ra \)2)-\( \alpha$-L-rhamnopyranoside-7-O-\( \alpha \)-L-rhamnopyranoside ({\bfseries 2}) and kaempferol 3-O-\( \alpha \)-L-rhamnopyranoside-7-O-\( \beta \)-D-glucopyranosyl-(1\( \ra \)2)-\( \alpha \)-L-rhamnopyranoside ({\bfseries 3}), were isolated for the first time from the flowers of {\itshape Consolida armeniaca}, and the structures of flavonol glycosides were deduced by high field 1D and 2D NMR and FAB-MS spectroscopies. The acetyl derivatives of {\bfseries 1-3} were also prepared ({\bfseries 1a, 2a, 3a}) and identified by NMR and positive FAB mass spectra.

Kinetics And Thermodynamics Of Oil Extraction From Sun Ower Seeds In The Presence Of Aqueous Acidic, Hüseyi̇n Topallar, Ümi̇t Geçgel

Turkish Journal of Chemistry

Oil extraction was performed in aqueous HCl, H_2SO_4 and H_3PO_4 solutions with n-hexane (C_6H_{14}) at 30, 40, 50 and 60 ^oC using 10 gr of sunflower seeds over 1 h with 10-min. sampling intervals. The optimum acid concentration was wt. 10% for each acid, and the highest oil yield was obtained in the extraction procedure with n-hexane containing H_2SO_4. The extraction process was observed with regard to the percent oil yield versus time, and the reaction order was found to be first-order kinetics by the differential method. The activation energy for the oil extraction kinetics of sunflower seeds with 10% …

The Rate Of Grafting And Some Kinetic Parameters Of The Graft Copolymerization Of Methacrylic Acid On Poly (Ethylene Terephthalate) Fibers With Azobisisobutyronitrile, Meltem Çeli̇k, Mehmet Saçak

Turkish Journal of Chemistry

In this study the rate of grafting and some kinetic parameters of the graft copolymerization of methacrylic acid on poly(ethylene terephthalate) fibers with azobisisobutyronitrile was investigated. The rate of grafting was found to be proportional to the 0.94 and 1.22 powers of initiator and monomer concentrations, respectively. By carrying out the graft copolymerization reaction at four different temperatures ranging from 70 ^oC to 90 ^oC, the overall rate activation energy of the reaction was found to be 130.4 kJ/mol. The overall rate constants were also calculated.

Electrothermal Atomic Absorption Spectrometric Determination Of Nickel After Its Flotation Enrichment By Iron(Iii) Hexamethylenedithiocarbamate, Trajce Stafilov, Gorica Pavlovska, Katarina Cundeva

Turkish Journal of Chemistry

Abstract. Nanogram quantities of nickel were removed from 1 L samples of dilute aqueous solutions by coflotation. A mixture of hydrated iron(III) oxide (Fe_2O_3\( \cdot \)xH_2O) and iron(III) hexamethylene-dithiocarbamate (Fe(HMDTC)_3) served as collectors. After flotation separation from the mother liquor, the solid sublate containing nickel traces was dissolved and the analyte was determined by electrothermal atomic absorption spectrometry (ETAAS). All important parameters necessary for the successful collection of nickel were checked. The results of nickel ETAAS analysis in tap and spring waters were compared with inductively coupled plasma-atomic emis-sion spectrometric measurements (ICP-AES). The limit detection of nickel by the ETAAS …

Investigation Of The Influence Of Thiocarbamide In The Process Of Carbamide Deparaffinization, Sevi̇l Veli̇yeva

Turkish Journal of Chemistry

The influence of thiocarbamide in the process of carbamide dewaxing was investigated. The dependence of separated paraffins on the quantity of thiocarbamide was examined experimentally. It was determined that the separation of paraffins becomes equal to zero when moles of carbamide and thiocarbamide in water-isopropyl alcohol solution are equal. The low-temperature qualities (the temperature of dimness and freezing) of dewaxed fuels were also examined. By using infrared spectroscopy methods, the compound of received paraffins was investigated.

Surrounding Denver Metro Smart Sign Study Summer 2000, Michael Duncan

Fuel Efficiency Automobile Test Publications

No abstract provided.

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.

Silver(I) Complexation Of (Poly)Aromatic Ligands. Structural Criteria For Depth Penetration Into Cis-Stilbenoid Cavities, Sergey V. Lindeman, Rajendra Rathore, Jay K. Kochi

Chemistry Faculty Research and Publications

Silver(I) complexes with aromatic donors are thoroughly analyzed (with aid of the Cambridge Crystallographic Database) to identify the basic structural factors inherent to the bonding of an arene ligand. Most strikingly, the distance parameter d (which simply measures the normal separation of Ag from the mean aromatic plane) is singularly invariant at d = 2.41 ± 0.05 Å for all silver/arene complexes, independent of the hapticity (η¹ or η²), hybridization, or multiple coordination. As such, a systematic series of stilbenoid ligands has been successfully designed to precisely modulate the penetration of silver(I) into the ligand cleft, and …

Electrophilic Aromatic Nitrosation. Isolation And X-Ray Crystallography Of The Metastable No+ Complex With Nitrosoarene, Sergey V. Lindeman, E. Bosch, Jay K. Kochi

Chemistry Faculty Research and Publications

Isolation of the unstable 1∶1 complex of 4-nitrosoanisole with NO⁺PF₆⁻ allows its precise X-ray structural characterization. The charge-transfer crystal is formed via strong N⋯N coordination [the distance of 1.938(5) Å corresponding to a σ-bond order of ≈0.2] in the mean plane of the planar 4-nitrosoanisole donor. Thorough analysis of its molecular geometry in terms of valence resonance and MO schemes reveals a strong charge polarization with a local negative charge localized on the nitroso group and a local positive charge distributed over the adjacent p-methoxybenzyl moiety. Such a charge distribution accommodates the well-known passivation of …

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 …

Cytotoxic Mab From Rheumatic Carditis Recognizes Heart Valves And Laminin, Jeffrey E. Galvin, Mark E. Hemric, Kent Ward, Madeleine W. Cunningham

Faculty Publications and Presentations

Anti-streptococcal antibodies cross-reactive with N-acetyl-bD-glucosamine (GlcNAc) and myosin are present in the sera of patients with rheumatic fever (RF). However, their role in tissue injury is not clear. In this study, we show that anti-GlcNAc/anti-myosin mAb 3.B6 from a rheumatic carditis patient was cytotoxic for human endothelial cell lines and reacted with human valvular endothelium and underlying basement membrane. Reactivity of mAb 3.B6 with the valve was inhibited by human cardiac myosin > laminin > GlcNAc. The mAb 3.B6 epitopes were localized in fragments of human cardiac myosin, including heavy meromyosin (HMM), the S1 subfragment, and two light meromyosin (LMM) peptides containing …

The Attempted Synthesis Of 4,4'-Bis(Dimethylamino)Azobenzene-3,3'-Disulfonylchloride As A Cap For Beta-Cyclodextrin, Katherine M. Ross

Dissertations, Theses, and Masters Projects

No abstract provided.

Applicability Of Ozone In Small Drinking Water Systems, Craig D. Adams, Justin Sutherland

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The use of ozone in water treatment plants is expanding rapidly in the United States. Ozone offers excellent disinfection properties (including chlorine-resistant pathogens) and does not form trihalomethanes. Additionally, ozone can be used to achieve or control many other water quality parameters such as color, taste and odor, and inorganic and organic contaminant concentrations. Control of ozone's disinfection byproducts such as bromate (formed in high bromide waters) is required. This presentation will review the synergistic effects of ozone applicable to use in small water treatment plants.

Structural And Electrical Characterization Of A Novel Mixed Conductor: Ceo2 - Sm2O3 - Zro2 Solid Solution, W. Huang, P. Shuk, M. Greenblatt, M. Croft, Fanglin Chen, M. Liu

Faculty Publications

solid solutions were synthesized for the first time by the hydrothermal method. The electrical properties of the solid solutions have been studied in air and under reducing conditions. Solid solutions with the fluorite structure were formed in all of the studied range of substitution after calcination at 1500°C. With increasing substitution up to 30 mol %, the electronic conductivity increases under a reducing atmosphere. The solid solution has good mixed electronic and ionic conductivity; the total conductivity is 0.42 S/cm at and 700°C with an estimated ionic conductivity of ca. .

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 …

Investigations Into The Synthesis And Transformations Of An Epoxy Β-Lactone, John Farrell

Masters Theses

In connection with the continuing interests in the stereoselective rearrangements of β-lactones, an investigation of the synthesis and transformations of the epoxy β-lactone 4-(1,2-epoxypentyl)-3-trimethylsilyloxetan-2-one was undertaken. Two synthetic strategies to the desired epoxy β-lactone were studied. The first route was a two-step reaction sequence involving the aldol reaction of trimethylsilylacetic acid with (2R,3S)-epoxyhexanal, followed by lactonization of the resulting β-hydroxy acid with benzenesulfonyl chloride. Complications in preparing the requisite β-hydroxy acids under typical aldol reaction conditions rendered this route unworkable. The complexity and intractability of the aldol reaction mixtures was attributed to the multiple possibilities of …

Validation Of The Thermochemical Cycle Used In Computing Absolute Gas Phase Acidities And A Molecular-Orbital Study Of Protonated Ammonia-Water Cluster Ions, Jeremiah Aeschleman

Masters Theses

This work is comprised of two separate computational projects, an evaluation of the validity of an assumption made when computing absolute gas phase acidities with a thermochemical cycle and a molecular-orbital study of protonated ammonia-water clusters ions.

Relative gas phase acidities are measured experimentally and then adjusted using Hess' law to align them with an absolute scale. In the Hess' law calculation it is assumed that the electron affinity of A• and the ionization energy of H• are independent of temperature. To test this assumption, absolute enthalpies were computed for the anion (A^-) and the radical (A•) at …

Degradation Of Trazine Compounds Via Metallic Iron Under Acidic Conditions, Tracy Dombek

Masters Theses

The degradation of dissolved dimethoxyatrazine (2-chloro-4,6-dimethoxy-1,3,5-triazine), terbutylazine (2-chloro-4-ethylamino-6-terbutylamino-1,3 ,5-triazine) and deisopropylatrazine (2-amino-4-chloro-6-ethylamino-1,3,5-triazine) via metallic iron was studied as a function of solution pH. Generally, degradation was more rapid the lower the solution pH and higher the compound pKa. For dimethoxyatrazine k_SA (k_SA= k' (min^-1)* V (L) / M (g) I SA(m²/g)) was found to be 1.33 (± 0.07) E-4 min^-1 m^-2 L at pH 2, 6.1 (± 0.6) E-5 min^-1 m^-2 L at pH 3 and 4.4 (± 0.6) E-5 min^-1 m^-2 L at pH 4. For …

Infrared Spectro-Electrochemistry, Mark Anderson, C. Douglas Taylor

Mark R. Anderson

The combination of infrared (IR) spectroscopy and electrochemistry in a single measurement has been an area of active research interest since the late 1960s. IR spectroelectrochemical experiments provide insight about interfacial electrochemical phenomena and/or oxidation–reduction reaction mechanisms that cannot be obtained using either technique individually. The power of the measurement is in the complementary nature of the spectroscopic and electrochemical information available when obtained simultaneously. The combination of measurements, however, requires compromise between the IR spectroscopy and the electrochemistry because of their different sampling requirements. The need for compromise illustrates the unique strengths and weaknesses of the combined spectroelectrochemical measurement. …

Making Connections Between Metallofullerenes And Fullerenes: Electrochemical Investigations, Mark Anderson, Harry Dorn, Steven Stevenson

Mark R. Anderson

The square-wave voltammetry for a series of related fullerenes and metallofullerenes measured in pyridine solutions containing 0.10 M tetra-n-butylammonium perchlorate is reported. Several dimetallic metallofullerenes, M2@Cx (where M=Sc or Er, and x=82 or 84), are found to have similar voltammetric responses regardless of metal identity or carbon number. Assignment of formal charges to the fullerene cage suggests that these metallofullerenes are isoelectronic and have related molecular orbital structures. The voltammetry of the empty C82 and D2d-C84 cages are also alike, but are different from the square-wave voltammetry of the C60, C70, and D2-C84. The similarity of the voltammetry for C82 …

The Discovery-Oriented Approach To Organic Chemistry. 3. Boron-Trifluoride Catalyzed Rearrangement Of Cis- And Trans-Stilbene Oxides. An Exercise In 1H Nmr Spectroscopy For Sophomore Organic Laboratories, Ram S. Mohan, Erik A. Sgariglia, Regina Schopp, Kostas Gavardinas

Ram S. Mohan

Isolation Of Curcumin From Tumeric, Ram S. Mohan, Andrew M. Anderson, Matthew S. Mitchell

Ram S. Mohan

No abstract provided.

Bismuth(Iii) Oxide Perchlorate Promoted Rearrangement Of Epoxides To Aldehydes And Ketones, Ram S. Mohan, Andrew M. Anderson, Jesse M. Blazek, Parie Garg, Brian J. Payne

Ram S. Mohan

Probing The Mechanisms Of Enantioselective Hydrogenation Of Simple Olefins With Chiral Rhodium Catalysts In The Presence Of Anions, Jillian M. Buriak, Jason C. Klein, Deborah Herrington, John A. Osborn

Peer Reviewed Articles

The strong influence of various anions upon the hydrogenation of 2-phenyl-1-butene, catalyzed by chiral rhodium catalysts was investigated. Both sulfonates and halides exert large increases in the enantioselectivity when [Rh{(−)-bdpp}(NBD)]ClO4 (bdpp=2,4-bis(diphenylphosphino)pentane, NBD=2,5-norbornadiene) is used as the catalyst precursor at high pressures (70 atm) of dihydrogen in nonpolar solvents. A dihydride mechanism similar to that for Wilkinson's catalyst [RhCl(PPh3)3] was shown to be operating at both high- and low-pressure conditions through a combination of catalytic studies, 31P, 1H and parahydrogen-induced polarization (PHIP) NMR experiments. With sulfonate and in neat methanol, however, a mechanistic switch takes place from a dihydride route (dihydrogen …

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 …

A Patching Model For Surface Tension Of Spherical Droplet And Tolman Length. Ii, T.V. Bykov, Xiao Cheng Zeng

Xiao Cheng Zeng Publications

In the framework of density functional theory (DFT), two patching models for the density profile of spherical liquid droplet are developed. The patching is based on analytical expressions of the asymptote of the density profiles. The first model leads to analytic expressions of the Tolman length and the effective rigidity constant, from which the temperature dependence of the Tolman length and effective rigidity constant can be determined. The second model is developed particularly for small spherical droplets, from which the dependence of chemical potential and the surface tension of the droplet on the radius are obtained. The results are compared …

Synthesis And Reactivity Of Acyclic (Pentadienyl)Iron(1+) Cations: Model Studies For The Preparation Of The 8E,10Z,16E,18E-Tetraene Segment Of Macrolactin A, Abdel-Aziz S. El-Ahl, Young Yun, William Donaldson

Chemistry Faculty Research and Publications

The dicarbonyl(1,2-dimethylpentadienyl)triphenylphosphineiron(1+) cation (11) has been prepared from methyl 4-methyl-2E,4E-hexadienoate in four steps. The cation (11) reacts with hydride and carbon nucleophiles in a regiospecific fashion to afford (3-methyl-2E,4Z-diene)iron complexes. Dicarbonyl(3-methyl-7-nitro-2E,4Z-heptadiene)triphenylphosphineiron (15), the product from the reaction of 11 with nitromethane anion, has been utilized as a precursor for nitrile oxide–olefin cyclocondensations.

Langmuir Monolayers As Disordered Solids: Disorder And Elastic Fluctuations In Mesophases , Tadeusz Luty, Craig J. Eckhardt, Jacques Lefebvre

Craig J. Eckhardt Publications

Ordering in Langmuir monolayer mesophases is examined using an approach based on the elastic theory of crystals. Molecular tails are modeled as ‘‘defects’’ grafted onto a two-dimensional elastic medium and are characterized by elastic dipoles. It is assumed that disorder in the parent, LS, phase is due to competition between local (within a domain) and global (hexagonal arrangement of domains) structure. By treating the LS phase as a mixture of rectangular and/or oblique domains (rectangular and/or oblique defects within the two-dimensional elastic medium), density fluctuations due to elastic interactions between domains are analyzed. The correlation function for the elastic dipoles …

12. Pierre Sigwalt, Otto Vogl

Otto Vogl

No abstract provided.