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Articles 27781 - 27810 of 34721

Full-Text Articles in Physical Sciences and Mathematics

Investigation Of Model Cell Membrane Disruption Via Fluorescence And Light Scattering Techniques, Imara Charles Jan 2003

Investigation Of Model Cell Membrane Disruption Via Fluorescence And Light Scattering Techniques, Imara Charles

Seton Hall University Dissertations and Theses (ETDs)

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Molecular Recognition Of No/No+ Via Multicenter (Charge-Transfer) Binding To Bridged Diarene Donors. Effect Of Structure On The Optical Transitions And Complexation Thermodynamics, Sergiy V. Rosokha, Sergey V. Lindeman, Rajendra Rathore, Jay K. Kochi Jan 2003

Molecular Recognition Of No/No+ Via Multicenter (Charge-Transfer) Binding To Bridged Diarene Donors. Effect Of Structure On The Optical Transitions And Complexation Thermodynamics, Sergiy V. Rosokha, Sergey V. Lindeman, Rajendra Rathore, Jay K. Kochi

Chemistry Faculty Research and Publications

Bridged diarenes form very strong [1:1] complexes with nitrosonium/nitric oxide in which the NO moiety is optimally sandwiched in the cleft between a pair of cofacial aromatic rings which act as a molecular “Venus flytrap”. The spectral features of these associates are generally similar to those for [1:1] and [2:1] nitrosonium complexes with mononuclear alkyl-substituted benzenes, and they are appropriately described within the LCAO molecular-orbital methodology and the Mulliken (charge-transfer) formulation of donor/acceptor electronic transitions. The thermodynamics study indicates that the efficient binding is determined by (i) the close matching of the donor/acceptor redox potentials and (ii) the ability of …

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Nanocomposites Based On Poly (Ε-Caprolactone) (Pcl)/Clay Hybrid: Polystyrene, High Impact Polystyrene, Abs, Polypropylene And Polyethylene, Xiaoxia Zheng, Charles A. Wilkie Jan 2003

Nanocomposites Based On Poly (Ε-Caprolactone) (Pcl)/Clay Hybrid: Polystyrene, High Impact Polystyrene, Abs, Polypropylene And Polyethylene, Xiaoxia Zheng, Charles A. Wilkie

Chemistry Faculty Research and Publications

Nanocomposites of polystyrene, high impact polystyrene, acrylonitrile–butadiene–styrene terploymer, polypropylene and polyethylene have been prepared using an organically-modified clay that contains polycaprolactone—PCL-modified clay. Depending upon the mode of preparation of the PCL-modified clay, all three types of nanocomposites, immiscible, intercalated and exfoliated, may be produced. The materials have been characterized by X-ray diffraction, transmission electron microscopy, cone calorimetry, thermogravimetric analysis, and the evaluation of mechanical properties.

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The Redox Potential Of Ddt: An Environmental Perspective, Anne Lewis, Christopher Cramer, John Bumpus Jan 2003

The Redox Potential Of Ddt: An Environmental Perspective, Anne Lewis, Christopher Cramer, John Bumpus

Presidential Scholars Theses (1990 – 2006)

Due to their low water solubility, the reduction potentials of DDT and dicofol are difficult to determine experimentally. Through computational methods, we calculated the one and two electron reduction potentials for DDT as 0.51 V and 0.67 V, respectively, and those for dicofol were 0.50 V and 0.74 V. This study is significant because we are able to calculate reliable redox potentials that may be utilized to predict chemical behavior and degradation pathways of environmental pollutants. To assess the accuracy of theoretical chemistry, we compared experimental and computational data and examined whether our calculated redox potentials fit with the known …

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Mechanistic Studies On Chlorinated Polymeric Systems, Jing Zhang Jan 2003

Mechanistic Studies On Chlorinated Polymeric Systems, Jing Zhang

Dissertations, Theses, and Masters Projects

No abstract provided.

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Solving Chemical Problems Of Environmental Importance Using Cavity Ring-Down Spectroscopy, Dean B. Atkinson Jan 2003

Solving Chemical Problems Of Environmental Importance Using Cavity Ring-Down Spectroscopy, Dean B. Atkinson

Chemistry Faculty Publications and Presentations

Cavity ring-down (CRD) is a sensitive variant of traditional absorption spectroscopy that has found increasing use in a number of chemical measurement applications. This review focuses on applications of cavity ring-down spectroscopy that will be of interest to environmental chemists and analytical chemists working on environmental problems. The applications are classified into direct monitoring approaches, indirect analysis methods and ancillary studies and a differentiation is made between field-tested instruments and proof of principle studies.

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Effects Of A Yec Apologetics Class On Student Worldview, David A. Dewitt, Steve Deckard, Sharon E. Cargo Jan 2003

Effects Of A Yec Apologetics Class On Student Worldview, David A. Dewitt, Steve Deckard, Sharon E. Cargo

Faculty Publications and Presentations

Creationism is a significant component of an overall Christian worldview. A Creation Worldview Test (CWT) was administered to students both before and after completion of a required Apologetics course dealing with the creation/evolution controversy. Pre-test analysis revealed that incoming students tend to have a creationist worldview, however their CWT scores reflected a degree of uncertainty or neutrality on scientific creation and the age of the earth. Post-test analysis showed a significant shift toward a young earth creationist (YEC) view. Implications for teaching apologetics and development of a Creationist worldview based on a Six-day Young Earth perspective were explored and identified.

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Water Quality Characterization And Mathematical Modeling Of Dissolved Oxygen In The East And West Ponds, Jamaica Bay Wildlife Refuge, Krishnanand Maillacheruvu, D Roy, John Tanacredi Ph.D. Jan 2003

Water Quality Characterization And Mathematical Modeling Of Dissolved Oxygen In The East And West Ponds, Jamaica Bay Wildlife Refuge, Krishnanand Maillacheruvu, D Roy, John Tanacredi Ph.D.

Faculty Works: CERCOM (1977-2016)

The current study was undertaken to characterize the East and West Ponds and develop a mathematical model of the effects of nutrient and BOD loading on dissolved oxygen (DO) concentrations in these ponds. The model predicted that both ponds will recover adequately given the average expected range of nutrient and BOD loading due to waste from surface runoff and migratory birds. The predicted dissolved oxygen levels in both ponds were greater than 5.0 mg/L, and were supported by DO levels in the field which were typically above 5.0 mg/L during the period of this study. The model predicted a steady-state …

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Self-Aggregates Of Cationic Meso-Tetratolylporphyrins In Aqueous Solutions, Pavel Kubat, Kamil Lang, Kristina Prochazkova, Pavel Anzenbacher Jr. Jan 2003

Self-Aggregates Of Cationic Meso-Tetratolylporphyrins In Aqueous Solutions, Pavel Kubat, Kamil Lang, Kristina Prochazkova, Pavel Anzenbacher Jr.

Chemistry Faculty Publications

Aggregation properties of meso-tetratolylporphyrins bearing cationic substituents of a lipophilic nature such as ammonium, pyridinium, phosphonium, sulfonium, and isothiouronium were studied by UV/vis and resonance light scattering spectroscopy. The exciton point-dipole approximation was used to predict the structural alignment of the porphyrin units within the aggregate. The contribution of various types of aggregates depends on the porphyrin substitution, ionic strength, and temperature of aqueous solution of the porphyrin. In general, the preferred structure of an aggregate formed by temperature-induced aggregation is the J-aggregate exhibiting the characteristically narrow, red-shifted Soret band indicating a parallel "side-by-side" arrangement of the porphyrin units. The …

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Photoinduced Electron-Transfer Along Alpha-Helical And Coiled-Coil Metallopeptides, Anna Fedorova, Anita Chaudhari, Michael Y. Ogawa Jan 2003

Photoinduced Electron-Transfer Along Alpha-Helical And Coiled-Coil Metallopeptides, Anna Fedorova, Anita Chaudhari, Michael Y. Ogawa

Chemistry Faculty Publications

A peptide-based electron-transfer system has been designed in which the specific positions of redox-active metal complexes appended to either an a-helix, or an a-helical coiled-coil, can be reversed to test the effect of the helix dipole in controlling photoinduced electron-transfer rates. Two 30-residue apopeptides were prepared having the following sequences: (1) Ac-K-(IEALEGK)(ICALEGK)(IEALEHK)-(IEALEGK)-G-amide, and (II) Ac-K-(IEALEGK)(IHALEGK)-(IEALECK)(IEALEGK)-G-amide. Each apopeptide was reacted first with [Ru(bpy)(2)(phen-ClAc)](2+), where bpy = 2,2'-bipyridine and phen-ClAc = 5-chloroacetamido-1,10-phenanthroline, to attach the ruthenium polypyridyl center to the cysteine side-chain of the polypeptide. The isolated products were then reacted with [Ru(NH3)(5)(H2O)](2+) to yield the binuclear electron-transfer metallopeptides ET-I and ET-II. …

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The Roles Of Silanes As Coupling Reagents And In Deoxygenative Alkylations, Andrea S. Dupre Jan 2003

The Roles Of Silanes As Coupling Reagents And In Deoxygenative Alkylations, Andrea S. Dupre

LSU Master's Theses

Silane reagents play important roles in many areas of organic synthesis. This is primarily due to the ability of silanes to bond to more ligands than the traditional four to become hypervalent (i.e. penta- or hexavalent). This hypervalency causes the silicon center to become more Lewis Acidic and causes the formation of carbon nucleophiles from organosilane ligands. These nucleophiles have been used to perform many cross-coupling reactions with organohalide reagents. The research presented in this thesis reports the utility of silane reagents in cross-coupling reactions of Grignard reagents with alkyl halides. This cross coupling was desirable because the silane should …

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The Aqueous Phase Yield Of Alkyl Nitrates From Roo+No: Implications For Photochemical Production In Seawater, Elizabeth E. Dahl, Eric S. Saltzman, Warren J. De Bruyn Jan 2003

The Aqueous Phase Yield Of Alkyl Nitrates From Roo+No: Implications For Photochemical Production In Seawater, Elizabeth E. Dahl, Eric S. Saltzman, Warren J. De Bruyn

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Alkyl nitrates have been observed in remote oceanic regions of the troposphere and in the surface ocean. The mechanism for their production in the oceans is not known. A likely source is the reaction of ROO + NO (where R is an alkyl group). Steady-state laboratory experiments show that alkyl nitrates are produced in the aqueous phase via this reaction, with branching ratios of 0.23 +/- 0.04, 0.67 +/- 0.03, and 0.71 +/- 0.04 for methyl, ethyl, and propyl nitrate respectively. The branching ratios in aqueous solution are significantly higher than in the gas phase. Irradiation of surface seawaters yield …

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Approaches To The Synthesis Of Novel Triptycene Dendrimers And Hyperbranched Poly(Phenylene Sulfides) And Poly(Phenylene Sulfones), Alfredo Mellace Jan 2003

Approaches To The Synthesis Of Novel Triptycene Dendrimers And Hyperbranched Poly(Phenylene Sulfides) And Poly(Phenylene Sulfones), Alfredo Mellace

Seton Hall University Dissertations and Theses (ETDs)

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Fenske-Hall Approximate Molecular Orbital Analysis Of The Chelating Carbene Complex Eta5-Cp'(Co)Mn{C(Oet)Ch2pph2}, John P. Graham Jan 2003

Fenske-Hall Approximate Molecular Orbital Analysis Of The Chelating Carbene Complex Eta5-Cp'(Co)Mn{C(Oet)Ch2pph2}, John P. Graham

Journal of the Arkansas Academy of Science

The novel three legged piano stool chelating carbene complex, Cp'(CO)Mn{C(OEt)CH2PPh2}, 1, exhibits interesting structural, spectroscopic and electrochemical properties. It also readily undergoes reaction with CO to produce the three legged piano stool complex Cp'(CO)2{PPh2C(OEt)=CH2}, 2. This is in contrast to the analogous non-chelating complex Cp(CO)(PPh3)Mn{C(OMe)CH2CH3}, 3, which does not react with CO. This paper discusses the results of Fenske-Hall approximate molecular orbital calculations on model complexes for 1 and 3. The differences in spectroscopic and electrochemical properties are explained using molecular orbital analysis. Possible reasons for the enhanced reactivity of 1are also presented.

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Stabilization Of Polyvinyl Chloride By Some Conducting Polymers, Amit Shah, Brian C. Berry, Ali U. Shaikh Jan 2003

Stabilization Of Polyvinyl Chloride By Some Conducting Polymers, Amit Shah, Brian C. Berry, Ali U. Shaikh

Journal of the Arkansas Academy of Science

No abstract provided.

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Adsorption And Reaction Of Benzaldehyde On Porous Glass Studied By Ftir And Tpd, Steven Michael Badger Ii Jan 2003

Adsorption And Reaction Of Benzaldehyde On Porous Glass Studied By Ftir And Tpd, Steven Michael Badger Ii

Dissertations and Theses @ UNI

Benzaldehyde was dosed onto porous borosilicate glass in order to better understand the catalytic behavior of the surface of the porous glass. 18,000 L of benzaldehyde was dosed onto the porous glass at approximately 50 K and heated to a temperature of 470 K. The reactions that occurred were studied using FTIR spectroscopy and Temperature Programmed Desorption (TPD). The FTIR spectrum of the porous glass confirmed the presence of isolated surface hydroxyl groups (Si-OH), seen in the spectrum at 3750 cm1 , and the presence of isolated boron-OH groups, seen in the spectrum at 3700 cm1 . Neighboring surface hydroxyl …

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Synchrotron Radiation As A Probe Of Chemical Information Using Novel Experimental Configurations, George Farquar Jan 2003

Synchrotron Radiation As A Probe Of Chemical Information Using Novel Experimental Configurations, George Farquar

LSU Doctoral Dissertations

Determination of chemical information with synchrotron radiation is an area of great scientific interest, and expanding the range of available techniques is the topic of this dissertation. The experimental methods described herein allows for a significant advancement of the availability of subtle chemical information. This dissertation uses ionizing radiation to study three chemical systems. First, the l=3 shape resonance in CO is investigated using a cryogenically cooled gas jet. Shape resonant effects have been studied for many years. Previously, this was accomplished on the vibrational structure of molecules with a limited ability to determine the rotational substructure effects. A dramatic …

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Solid-Phase Dna Sequencing Reactions Performed In Micro-Capillary Reactors And Solid-Phase Reversible Immobilization In Microfluidic Chips For Purification Of Dye-Labeled Dna Sequencing Fragments, Yichuan Xu Jan 2003

Solid-Phase Dna Sequencing Reactions Performed In Micro-Capillary Reactors And Solid-Phase Reversible Immobilization In Microfluidic Chips For Purification Of Dye-Labeled Dna Sequencing Fragments, Yichuan Xu

LSU Doctoral Dissertations

The research presented in this dissertation involves micro-capillary reactors for solid phase DNA sequencing, the identification of dye terminator sequencing fragments with time-resolved methods, and purification of dye-labeled DNA fragments using solid- phase reversible immobilization in microfluidic chips. Solid-phase micro-reactors have been prepared for DNA sequencing applications using slab gel electrophoresis. A PCR product was immobilized to the interior wall of a fused-silica capillary tube via a biotin-streptavidin linkage. Solid-phase sequencing was carried out in micro-capillary reactors using a four-lane, single color dye primer chemistry strategy. The read length was found to be 589 bases. The complementary DNA fragments generated …

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Photochemical Reactions Of \Alpha-Terpinene And Acenaphthene Under Concentrated Sunlight, Nesi̇be Avcibaşi, Siddik İçli̇, Andrew Gilbert Jan 2003

Photochemical Reactions Of \Alpha-Terpinene And Acenaphthene Under Concentrated Sunlight, Nesi̇be Avcibaşi, Siddik İçli̇, Andrew Gilbert

Turkish Journal of Chemistry

\alpha-Terpinene was successfully dehydrogenated to p-cymene in photocatalytic reaction with benzophenone and cupric ions under 40 suns concentrated sunlight irradiation, proving that photodehydrogenation reactions may be employed for the synthesis of fine chemicals under sunlight. Acenaphthene dehydrogenation under concentrated sunlight resulted in the minor formation of acenaphthylene and the quantitative formation of acenaphthenone when the solution was aerated. Stable benzylic-type radical intermediates are thought to lower the yield of dehydrogenation reactions.

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Polyethyleneimine-Coated Capillaries For The Separation Of Dna By Capillary Electrophoresis, M. Sai̇d Nutku, F. Bedi̇a Eri̇m Berker Jan 2003

Polyethyleneimine-Coated Capillaries For The Separation Of Dna By Capillary Electrophoresis, M. Sai̇d Nutku, F. Bedi̇a Eri̇m Berker

Turkish Journal of Chemistry

A new capillary electrophoresis of DNA fragments has been achieved with the cooperative effects of the electrophoretic and electroosmotic mobilities realized via the polyethyleneimine (PEI) coating of the capillary walls. As a result, seven of the 11 different-sized DNA fragments have produced resolved CE peaks. Our results demonstrate that analyses of DNA constituents can be performed under a wide range of conditions by the appropriate tuning of the coating and filler within the capillary.

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Search For A Nonelectrocyclic Cyclization Of Nitrosostyrene: Rearrangements Of Michael Adducts From Dmad And \Alpha-Dialkylamino Oximes, Necdet Coşkun, Nevi̇n Arikan Jan 2003

Search For A Nonelectrocyclic Cyclization Of Nitrosostyrene: Rearrangements Of Michael Adducts From Dmad And \Alpha-Dialkylamino Oximes, Necdet Coşkun, Nevi̇n Arikan

Turkish Journal of Chemistry

The aza-Claisen rearrangement product of the Michael adducts 2 from \alpha-dialkylaminoacetophenone oximes and DMAD underwent fragmentation to give dialkylaminomaleate, and benzonitrile at reflux in acetonitrile. The fragmentation was assumed to proceed through an unstable 4H-1,2-oxazete 6. The same reaction performed at room temperature, in addition to the nitrile and maleate, gave the corresponding 2-(2-dialkylamino-1-phenylethylideneaminooxy)-but-2- enedioic acid dimethyl esters 8 and 9. Compounds 9 isomerized to 8 on heating in acetonitrile.

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Changes In Chlorophyll-Carotenoid Contents, Antioxidant Enzyme Activities And Lipid Peroxidation Levels In Zn-Stressed Mentha Pulegium, Ni̇lgün Candan, Leman Tarhan Jan 2003

Changes In Chlorophyll-Carotenoid Contents, Antioxidant Enzyme Activities And Lipid Peroxidation Levels In Zn-Stressed Mentha Pulegium, Ni̇lgün Candan, Leman Tarhan

Turkish Journal of Chemistry

The relationships between chlorophyll-carotenoid contents, the antioxidant enzyme activities, such as superoxide dismutase (SOD), catalase (CAT), ascorbate-dependent peroxidase (AsA-dep POD) and guaiacol-dependent peroxidase (Gua-dep POD), and lipid peroxidation (LPO) levels were investigated in leaves at different positions of M. pulegium grown in nutrient medium containing 0-1 \mu M Zn. The maximum chlorophyll-carotenoid content's SOD and CAT activities and the minimum LPO level were observed in leaf 6 at 7.6 10^{-2} \mu M Zn (as control). While chlorophyll-carotenoid contents in the absence of Zn were lower than those of the control, SOD and CAT activities significantly increased with decreasing Zn concentration. …

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An Efficient Synthesis Of Alnustone, A Naturally Occurring Compound, Süleyman Göksu, Hülya Çeli̇k, Hasan Seçen Jan 2003

An Efficient Synthesis Of Alnustone, A Naturally Occurring Compound, Süleyman Göksu, Hülya Çeli̇k, Hasan Seçen

Turkish Journal of Chemistry

Alnustone, 4(E),6(E)-1,7-diphenyl-hepta-4,6-dien-3-one, was synthesized starting from benzaldehyde in three steps with an overall yield of 57%. The condensation of benzaldehyde with acetone gave benzalacetone. The Pd-C catalyzed hydrogenation of benzalacetone afforded benzylacetone. The in situ enamination of benzylacetone with pyrrolidine and acetic acid followed by cinnamaldehyde treatment gave alnustone.

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Synthesis Of Some New Benzimidazole Carbamate Derivatives For Evaluation Of Antifungal Activity, Canan Kuş, Nurten Altanlar Jan 2003

Synthesis Of Some New Benzimidazole Carbamate Derivatives For Evaluation Of Antifungal Activity, Canan Kuş, Nurten Altanlar

Turkish Journal of Chemistry

The synthesis and structure elucidation of methyl 5(6)-fluoro-6(5)-substituted-1H-benzimidazole carbamate derivatives are performed and their antifungal activities evaluated against Candida albicans.

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Determination Of H_{2}O_{2} Content Of Various Water Samples Using A Chemiluminescence Technique, Tuğba Tüğsüz, Elmas Gök, Serdar Ateş Jan 2003

Determination Of H_{2}O_{2} Content Of Various Water Samples Using A Chemiluminescence Technique, Tuğba Tüğsüz, Elmas Gök, Serdar Ateş

Turkish Journal of Chemistry

Hydrogen peroxide (H_{2}O_{2}) plays an important role in natural water samples. In this study H_{2}O_{2} concentrations were quantified in different water samples by chemiluminescence detection. This method was chosen because of its high sensitivity and suitability for determining low concentrations of H_{2}O_{2}. H_{2}O_{2} is introduced to the oxidation reaction of alkaline luminol solutions in the presence of Co^{2 + } ion catalyst. When these components are mixed, blue light (\lambda = 440 nm) is emitted. Maximum chemiluminescence intensity occurs within 2 s after mixing and is continuous for up to a few minutes, permitting accurate measurements at selected delay times. …

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Chromatographic Determination Of Phenolic Acids In The Snowdrop By Hplc, Mustafa Tüzen, Mustafa Özdemi̇r Jan 2003

Chromatographic Determination Of Phenolic Acids In The Snowdrop By Hplc, Mustafa Tüzen, Mustafa Özdemi̇r

Turkish Journal of Chemistry

Free and esterified phenolic acids of Galanthus elwesii (snowdrop) were extracted with petroleum ether and determined by HPLC. Cinnamic, ferulic, vanillic, p-coumaric, p-hydroxy benzoic, and caffeic acids were detected by a linear gradient elution with acetic acid/water (2:98 v/v) and acetic acid/acetonitrile/water (2:30:68 v/v) as the mobile phases in 30 min with a flow rate of 1.5 mL/min. Among the acids from snowdrop extracts, p-hydroxy benzoic was the major constituent followed by vanillic and ferulic acids.

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Thermal Decomposition Kinetics Of Anilino-P-Chlorophenylglyoxime Complexes Of Cobalt (Ii), Nickel (Ii) And Copper (Ii), Hakan Arslan, Nevzat Külcü, Ali̇ İhsan Pekacar Jan 2003

Thermal Decomposition Kinetics Of Anilino-P-Chlorophenylglyoxime Complexes Of Cobalt (Ii), Nickel (Ii) And Copper (Ii), Hakan Arslan, Nevzat Külcü, Ali̇ İhsan Pekacar

Turkish Journal of Chemistry

The Co(II), Ni(II) and Cu(II) complexes of anilino-p-chlorophenylglyoxime were synthesised. The thermal behaviour of all complexes was studied by DTA and TG. It was found that pyrolytic decomposition occurs with melting in metal complexes and that metal oxides remain as final products of the metal complexes. A GC-MS combined system was used to identify the products during pyrolytic decomposition. The pyrolytic end products were identified by x-ray powder diffraction. The orders, n, the activation energies, E^*, the pre-exponential factors, A, and the entropies, \Delta S^*, of thermal decomposition reactions were derived from thermogravimetric and differential thermogravimetric curves. The kinetic analysis …

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Differential Pulse Polarographic Determination Of Enalapril Maleate, Fi̇kri̇ye Elmali, Güzi̇n Alpdoğan, Şule Aycan, Sidika Sungur Jan 2003

Differential Pulse Polarographic Determination Of Enalapril Maleate, Fi̇kri̇ye Elmali, Güzi̇n Alpdoğan, Şule Aycan, Sidika Sungur

Turkish Journal of Chemistry

A differential pulse polarographic (DPP) method has been developed for the quantitative analysis of enalapril maleate. Enalapril maleate gives a peak at -1.4 V in methanol. A calibration curve was constructed for the 20 -100 \mu g ml^{-1} concentration range. As a reference method, a reversed phase high performance liquid chromatographic procedure has been developed. Commercially available tablets were analysed by the two methods. Statistical evaluations indicated that there was no significant difference between the mean values and precisions of the two methods at a 95\% confidence level.

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^1h Nmr Studies Of Some Imidazole Ligands Coordinated To Co(Iii), Kosrow Zamani, Akbar Mobinikhaledi, Naser Foroughifar, Khalil Faghihi, Vahid Mahdavi Jan 2003

^1h Nmr Studies Of Some Imidazole Ligands Coordinated To Co(Iii), Kosrow Zamani, Akbar Mobinikhaledi, Naser Foroughifar, Khalil Faghihi, Vahid Mahdavi

Turkish Journal of Chemistry

Chemical shifts for proton signals of an imidazole ring coordinated to Co(III) move downfield as the total complex charge increases. However, the C_{(2) - H} chemical shift of the imidazole ring in cis-[Co(en)_{2}(N-mIm) OPO_{3}H]°, which has no charge compared to those of cis-[Co(en)_{2}(N-mIm) OPO_{3}H]^{+} and cis}-[Co(en)_{2}(N-mIm) OPO_{3}H_{2}]^{2 +} , moves downfield. These unexpected phenomena could be attributed to an intramolecular interaction between the phosphate anion group and C_{(2) - H} of the imidazole ligand.

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Conductimetric And Potentiometric Investigation Of Effects Of Solvents And Titrant On Formation Of Homoconjugates, Esi̇n Canel, Mustafa Taşteki̇n, Orhan Atakol, Esma Kiliç Jan 2003

Conductimetric And Potentiometric Investigation Of Effects Of Solvents And Titrant On Formation Of Homoconjugates, Esi̇n Canel, Mustafa Taşteki̇n, Orhan Atakol, Esma Kiliç

Turkish Journal of Chemistry

Trichloro-, tribromo- and trifluoro- acetic acids were both conductimetrically and potentiometrically titrated in acetonitrile and 2-propanol media. The titrations were carried out at 25°C under nitrogen atmosphere and titrants used were the solutions of triethyl, di-n-butyl and n-butyl amines prepared in the same solvents. Whether these acids gave a homoconjugation reaction during titration was investigated by the use of conductimetric and potentiometric titration curves. In acetonitrile media trichloro- and tribromo-acetic acids decomposed to give chloroform and carbon dioxide, and bromoform and carbon dioxide respectively. It was observed that the acid concentration and the type of titrant used had no effect …

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