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Articles 26761 - 26790 of 34732

Full-Text Articles in Physical Sciences and Mathematics

Reaction Of Organosilicon Hydrides With Inorganic Surfaces: An Example Of Surface Catalyzed Self-Assembly And Water Porosimetry: A New Technique To Characterize Hydrophobic Porous Surfaces And Wetting In Nano-Confinement, Roy Helmy Jan 2005

Reaction Of Organosilicon Hydrides With Inorganic Surfaces: An Example Of Surface Catalyzed Self-Assembly And Water Porosimetry: A New Technique To Characterize Hydrophobic Porous Surfaces And Wetting In Nano-Confinement, Roy Helmy

Seton Hall University Dissertations and Theses (ETDs)

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Hydrophobic Guar Gum Derivatives Prepared By Controlled Grafting Processes For Hydraulic Facturing Applications, Ahmad Bahamdan Jan 2005

Hydrophobic Guar Gum Derivatives Prepared By Controlled Grafting Processes For Hydraulic Facturing Applications, Ahmad Bahamdan

LSU Doctoral Dissertations

The synthesis of new water soluble guar gum derivatives is described. Introduction of polyalkoxyalkyleneamide grafts to guar gum or hydroxyopropyl guar was achieved in a three step process: carboxymethylation with sodium chloroacetate, esterification with dimethyl sulfate and amidation with a series of polyalkoxyalkylene-amines. The process steps were followed using infrared spectroscopy; the grafted guar derivatives were characterized using FT-IR and 1H NMR. A series of hydroxypropyl guar derivatives with degrees of carboxymethylations ranging from 0.15-0.25 were modified with polyalkoxyalkyleneamines with molecular weights ranging from 300-3000. The ratio of oxypropylene to oxoethylene units in the polyalkoxyalkyleneamines was varied from 9/1 …

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Crystal Structure Of The Gtpase Domain Of Rat Dynamin 1, Thomas F. Reubold, Susanne Eschenburg, Andreas Becker, Marilyn Leonard, Sandra L. Schmid, Richard B. Vallee, F. Jon Kull, Dietmar J. Manstein Jan 2005

Crystal Structure Of The Gtpase Domain Of Rat Dynamin 1, Thomas F. Reubold, Susanne Eschenburg, Andreas Becker, Marilyn Leonard, Sandra L. Schmid, Richard B. Vallee, F. Jon Kull, Dietmar J. Manstein

Dartmouth Scholarship

Here, we present the 1.9-A crystal structure of the nucleotide-free GTPase domain of dynamin 1 from Rattus norvegicus. The structure corresponds to an extended form of the canonical GTPase fold observed in Ras proteins. Both nucleotide-binding switch motifs are well resolved, adopting conformations that closely resemble a GTP-bound state not previously observed for nucleotide-free GTPases. Two highly conserved arginines, Arg-66 and Arg-67, greatly restrict the mobility of switch I and are ideally positioned to relay information about the nucleotide state to other parts of the protein. Our results support a model in which switch I residue Arg-59 gates GTP binding …

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Synthetic Studies In Phytochrome Chemistry, Peter A. Jacobi, Imad Odeh, Subhas Buddhu, Guolin Cai, Sundaramoorthi Rajeswari, Douglas Fry, Wanjun Zheng, Robert W. Desimone, Jiasheng Guo, Lisa D. Coutts, Sheila I. Hauck, Sam H. Leung, Indranath Ghosh, Douglas Pippin Jan 2005

Synthetic Studies In Phytochrome Chemistry, Peter A. Jacobi, Imad Odeh, Subhas Buddhu, Guolin Cai, Sundaramoorthi Rajeswari, Douglas Fry, Wanjun Zheng, Robert W. Desimone, Jiasheng Guo, Lisa D. Coutts, Sheila I. Hauck, Sam H. Leung, Indranath Ghosh, Douglas Pippin

Dartmouth Scholarship

An account is given of the author’s several approaches to the synthesis of the parent chromophore of phytochrome (1), a protein-bound linear tetrapyrrole derivative that controls photomorphogenesis in higher plants. These studies culminated in enantioselective syntheses of both (2R)- and (2S)-phytochromobilin (4), as well as several 13C-labeled derivatives designed to probe the site of Z,E-isomerization during photoexcitation. When reacted in vitro, synthetic 2R-4 and recombinant-derived phytochrome apoprotein N-C produced a protein-bound chromophore with identical difference spectra to naturally occurring 1.

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Scope And Mechanistic Study Of The Ruthenium-Catalyzed Ortho-C−H Bond Activation And Cyclization Reactions Of Arylamines With Terminal Alkynes, Chae S. Yi, Young Yun Jan 2005

Scope And Mechanistic Study Of The Ruthenium-Catalyzed Ortho-C−H Bond Activation And Cyclization Reactions Of Arylamines With Terminal Alkynes, Chae S. Yi, Young Yun

Chemistry Faculty Research and Publications

The cationic ruthenium hydride complex [(PCy3)2(CO)(CH3CN)2RuH]+BF4- was found to be a highly effective catalyst for the C−H bond activation reaction of arylamines and terminal alkynes. The regioselective catalytic synthesis of substituted quinoline and quinoxaline derivatives was achieved from the ortho-C−H bond activation reaction of arylamines and terminal alkynes by using the catalyst Ru3(CO)12/HBF4·OEt2. The normal isotope effect (kCH/kCD = 2.5) was observed for the reaction of C6H5NH2 and C …

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Isolation And X-Ray Structures Of Labile Benzoic- And Acetic-Acidium Carbocations, Sergey V. Lindeman, I. S. Neretin, M. G. Davlieva, Jay K. Kochi Jan 2005

Isolation And X-Ray Structures Of Labile Benzoic- And Acetic-Acidium Carbocations, Sergey V. Lindeman, I. S. Neretin, M. G. Davlieva, Jay K. Kochi

Chemistry Faculty Research and Publications

New carbocationic salts (via O-protonation of substituted benzoic acids) are prepared for the first time by controlled hydration of the corresponding benzoylium salts and isolated in pure crystalline form. Precise X-ray structural analyses reveal the rather unexpected (electronic) structure of the carboxylic-acidium functionality.

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Polyethylene And Polypropylene Nanocomposites Based Upon An Oligomerically-Modified Clay, Jinguo Zhang, David D. Jiang, Charles A. Wilkie Jan 2005

Polyethylene And Polypropylene Nanocomposites Based Upon An Oligomerically-Modified Clay, Jinguo Zhang, David D. Jiang, Charles A. Wilkie

Chemistry Faculty Research and Publications

Montmorillonite clay was modified with an oligomeric surfactant, which was then melt blended with polyethylene and polypropylene in a Brabender mixer. The morphology was characterized by X-ray diffraction and transmission electron microscopy, while thermal stability was evaluated from thermogravimetric analysis and the fire properties by cone calorimetry. The nanocomposites are best described as mixed immiscible/intercalated/delaminated systems and the reduction in peak heat release rate is about 40% at 5% inorganic clay loading.

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Studies Of Zeolite Entrapped Ruthenium Polypyridine Complexes, Anwar A. Bhuiyan Jan 2005

Studies Of Zeolite Entrapped Ruthenium Polypyridine Complexes, Anwar A. Bhuiyan

Journal of the Arkansas Academy of Science

There is an intense interest in designing molecular systems which will absorb visible sunlight, initiate an electron transfer process, and ultimately convert the solar energy to useful chemical energy of fuels such as hydrogen produced from water. The zeolite-entrapped polypyridine complexes of divalent ruthenium hold promise as efficient photocatalysts for net charge separation and such efficiencies are further enhanced by organized incorporation of donor and acceptor components. This paper deals with the synthesis and spectroscopic investigation of zeolite-entrapped ruthenium polypyridine complexes which may be useful in the development of solar energy conversion schemes. The sensitizer molecules, such as Ru(bpy)3 2+ …

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Nonaqueous Platination For Synthesis Of Platinated 7 Alpha-Substituted Estradiol, Sarah A. Mazzella Jan 2005

Nonaqueous Platination For Synthesis Of Platinated 7 Alpha-Substituted Estradiol, Sarah A. Mazzella

Masters Theses

No abstract provided.

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Voltammetric, Uv Absorption And Viscometric Studies Of The Interaction Of Norepinephrine With Dna, Mehmet Aslanoğlu, Necla Öge Jan 2005

Voltammetric, Uv Absorption And Viscometric Studies Of The Interaction Of Norepinephrine With Dna, Mehmet Aslanoğlu, Necla Öge

Turkish Journal of Chemistry

Voltammetric, UV-vis spectroscopic and viscometric methods were used to investigate the interaction between norepinephrine and DNA. The results of square wave voltammetric and UV-absorption measurements have shown that norepinephrine was bound to DNA. Besides the electrostatic interaction between DNA and norepinephrine, hydrogen bonds and intercalation may also exist. Viscosity measurements also suggest that NE is bound to DNA via an electrostatic mode of interaction at lower norepinephrine concentrations. However, at higher concentrations of norpinephrine, the increase in the relative viscosity of DNA indicated that the intercalation is also involved in the binding. The binding constant and the binding site size …

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The Crystal And Molecular Structure Of New Hydrogen Dinitrate Of Nitrato(2,2',2''-Terpyridyl)Platinum(Ii) Ion, [Pt(Terpy)Ono_2][H(Ono_2)_2], Abdurrahman Şengül Jan 2005

The Crystal And Molecular Structure Of New Hydrogen Dinitrate Of Nitrato(2,2',2''-Terpyridyl)Platinum(Ii) Ion, [Pt(Terpy)Ono_2][H(Ono_2)_2], Abdurrahman Şengül

Turkish Journal of Chemistry

The title compound, C_{15}H_{12}N_6O_9Pt, consists of [Pt(terpy)ONO_2]^+ cation and [H(ONO_2)_2]^- anion, in which 2 nitrate groups are linked by a strong hydrogen bond [O \cdots O 2449(1) Å]. In the cation, the terpyridine is coordinated to Pt as a tridentate ligand and the fourth position is occupied by the nitrate ion's oxygen. The coordination around Pt is square-planar. The coordinated nitrate moiety adopts a distorted trigonal-planar configuration. It belongs to the space group P \bar{1} with a = 8.605(2), b = 10.220(3) Å, c = 10.517(2) Å and \alpha = 89.51(1), \beta = 82.78(2), \gamma = 76.90(2)°.

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Polyphenolic Compounds And Antimicrobial Activity Of Quercus Aucheri Leaves, Mahmut Koray Sakar, Di̇dem Şöhretoğlu, Meral Özalp, Meli̇ke Eki̇zoğlu, Sonia Piacente, Cosimo Pizza Jan 2005

Polyphenolic Compounds And Antimicrobial Activity Of Quercus Aucheri Leaves, Mahmut Koray Sakar, Di̇dem Şöhretoğlu, Meral Özalp, Meli̇ke Eki̇zoğlu, Sonia Piacente, Cosimo Pizza

Turkish Journal of Chemistry

Chromatographic studies (CC, VLC, MPLC, and PTLC) on ethyl acetate extract from the leaves of Quercus aucheri yielded 2 flavonoids (quercetin 3-O-\alpha-L-arabinopyranoside (1), quercetin 3-O-\beta-D-galactopyranoside (2)) and 2 tannin precursors and a procyanidin [(isolated as peracetates of (+)-catechin (3a), (+)-gallocatechin (4a) and epicatechin-(4\beta \to 8)-catechin (5a))]. The structures of the compounds were elucidated by UV, 1D-NMR (^1H, ^{13}C, TOCSY) and 2D-NMR (COSY, HSQC, HMBC) techniques. Different extracts (80% MeOH, EtOAc, n-BuOH and H_2O) from the leaves of Q. aucheri were investigated for their antimicrobial activity against 2 Gram-positive and 2 Gram-negative bacteria and 3 yeast-like fungi by a broth microdilution …

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Selective Oxidation Of Thiols To Disulfides Catalyzed By Iron(Iii) -- Tetra Phenyl Porphyrin Using Urea-Hydrogen Peroxide As Oxidizing Reagent, Bahador Karimi, Morteza Montazerozohori, Majid Moghadam, Mohammad Hosein Habibi, Khodabakhsh Niknam Jan 2005

Selective Oxidation Of Thiols To Disulfides Catalyzed By Iron(Iii) -- Tetra Phenyl Porphyrin Using Urea-Hydrogen Peroxide As Oxidizing Reagent, Bahador Karimi, Morteza Montazerozohori, Majid Moghadam, Mohammad Hosein Habibi, Khodabakhsh Niknam

Turkish Journal of Chemistry

Oxidation of thiols to disulfides catalyzed by iron(III) -- tetra phenyl prophyrin Fe (TPP)Cl was investigated using urea-hydrogen peroxide adduct (UHP) as an oxidant in methanol as a solvent.

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Development Of Gold Porous Plate Electrode And Examination Of Its Performance For Iodine Determination, Ülkü Anik Kirgöz, Hüseyi̇n Tural Jan 2005

Development Of Gold Porous Plate Electrode And Examination Of Its Performance For Iodine Determination, Ülkü Anik Kirgöz, Hüseyi̇n Tural

Turkish Journal of Chemistry

A novel procedure for the construction of a home-made gold porous plate electrode is described. A plate of silver and gold alloy was treated with nitric acid or alternatively by anodic oxidation to remove the silver component, leaving a porous surface having active sites for adsorption. The performance of the electrode developed was tested using iodine solution as analyte material. The parameters related to the working conditions were optimized before the examination of analytical characteristics. Under the optimal conditions, the voltammetric results show that the gold porous plate electrode offers the detection limit of 2.18 x 10^{-5} M and reproducibility …

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Excellent And Convenient Procedures For Reduction Of Benzene And Its Derivatives, Ali̇ye Altundaş, Abdullah Menzek, Demet Demi̇rci̇ Gülteki̇n, Melek Karakaya Jan 2005

Excellent And Convenient Procedures For Reduction Of Benzene And Its Derivatives, Ali̇ye Altundaş, Abdullah Menzek, Demet Demi̇rci̇ Gülteki̇n, Melek Karakaya

Turkish Journal of Chemistry

Reductions of benzene, toluene, ortho-xylene, cumene, anisole and benzoic acid to corresponding nonconjugated dienes were realized at room temperature by gas NH_3 and Li. The reduced products were easily isolated because THF and dioxane were dissolved in the water. The yields and conversions of the reactions were 70-89% and 80-100%, respectively.

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A New Approach To The Ring Opening Reactions Of 2,7,7-Trimethyl-3,3-Dibromotricyclo[4.1.1.0^{2,4}]Octane, Zeki̇ Şenol, Ömer Zai̇m, Meti̇n Balci Jan 2005

A New Approach To The Ring Opening Reactions Of 2,7,7-Trimethyl-3,3-Dibromotricyclo[4.1.1.0^{2,4}]Octane, Zeki̇ Şenol, Ömer Zai̇m, Meti̇n Balci

Turkish Journal of Chemistry

The reaction of \alpha-pinene and dibromocarbene produced a fairly unstable product, 2,7,7-trimethyl-3,3-dibromotricyclo[4.1.1.0^{2,4}]octane, from which 3-bromo-7,7-dimethyl-2-methylenebicyclo[4,1,1]oct-3-ene and 3-bromo-2,7,7-trimethylbicyclo [4,1,1]octa-2,4-diene were obtained in chloroform at room temperature and in various other media and conditions. Two new compounds, 3-bromo-2,7,7-trimethylbicyclo [4.1.1]oct-3-en-2-ol and 2-(4-bromo-5-methylcyclohepta-3,5-dien-1-yl) propan-2-ol, were observed in aqueous acetone in addition to the previous two. The stability and formation mechanism of the formed products are discussed

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Miscibility Of Methylmethacrylate-Co-Methacrylic Acid Polymer With Magnesium, Zinc, And Manganese Sulfonated Polystyrene Ionomers, Cemi̇l Alkan, Nebahat Yurtseven, Leyla Aras Jan 2005

Miscibility Of Methylmethacrylate-Co-Methacrylic Acid Polymer With Magnesium, Zinc, And Manganese Sulfonated Polystyrene Ionomers, Cemi̇l Alkan, Nebahat Yurtseven, Leyla Aras

Turkish Journal of Chemistry

The miscibility of methyl methacrylate-co-methacrylic acid polymer (MMA-MAA) with metal neutralized sulfonated polystyrene ionomers was investigated by viscometry, differential scanning calorimetry (DSC), and Fourier transform infrared radiation spectroscopy (FTIR) techniques. Polystyrene (PS) was sulfonated by acetic anhydride and sulfuric acid and the sulfonation degree was found to be 2.6 mole percent, and 2.6 mole percent sulfonated polystyrene was neutralized by Mg, Zn, and Mn salts. The miscibility behavior of the blends of MMA-MAA with Mg neutralized 2.6 mole% sulfonated polystyrene (2.6MgSPS), Mn neutralized 2.6mole% sulfonated polystyrene (2.6MnSPS), and Zn neutralized 2.6 mole% sulfonated polystyrene (2.6ZnSPS) was investigated by dilute solution …

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Triterpene Saponins From Nigella Sativa L., Mustafa Kemal Taşkin, Özgen Alankuş Çalişkan, Hüseyi̇n Anil, Hassan Abou-Gazar, Ikhlas A. Khan, Erdal Bedi̇r Jan 2005

Triterpene Saponins From Nigella Sativa L., Mustafa Kemal Taşkin, Özgen Alankuş Çalişkan, Hüseyi̇n Anil, Hassan Abou-Gazar, Ikhlas A. Khan, Erdal Bedi̇r

Turkish Journal of Chemistry

Three known triterpene glycosides were isolated from the MeOH extract of dried and powdered seeds of Nigella sativa. The structures of the compounds were established as 3-O-[\beta-D-xylopyranosyl- (1 \to 3)-\alpha-L-rhamnopyranosyl-(1 \to 2)-\alpha -L-arabinopyranosyl]- 28-O-[\alpha-L-rhamnopyranosyl-(1 \to 4)-\beta-D-glucopyranosyl-(1 \to 6)- \beta-D-glucopyranosyl]-hederagenin (1), 3-O-[\alpha -L-rhamnopyranosyl- (1 \to 2)-\alpha-L-arabinopyranosyl]-28-O-[\alpha -L-rhamnopyranosyl-(1 \to 4)- \beta-D-glucopyranosyl-(1\to 6)-\beta-D-glucopyranosyl]-hederagenin (2), and 3-O-[\beta-D-xylopyranosyl- (1\to 3)-\alpha-L-rhamnopyranosyl-(1\to 2)-\alpha- L-arabinopyranosyl]-hederagenin (3) by means of chemical and spectral methods. Compound 2 was isolated for the first time from the genus Nigella.

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Analysis Of The Essential Oil Composition Of Sideritis Albiflora Using Direct Thermal Desorption And Headspace Gc-Ms Techniques, Gülaçti Topçu, Asli Barla, Ahmet C. Gören, Gökhan Bi̇lsel, Mi̇ne Bi̇lsel, Gülendam Tümen Jan 2005

Analysis Of The Essential Oil Composition Of Sideritis Albiflora Using Direct Thermal Desorption And Headspace Gc-Ms Techniques, Gülaçti Topçu, Asli Barla, Ahmet C. Gören, Gökhan Bi̇lsel, Mi̇ne Bi̇lsel, Gülendam Tümen

Turkish Journal of Chemistry

The main constituents of Sideritis albiflora were found to be trans-caryophyllene, \alpha-pinene, \beta-pinene, \gamma-cadinene, pulegone, and caryophyllene oxide by both thermal desorption GC/MS and headspace GC/MS techniques.

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An Unusual Pentacyclic Dinitrogenous Alkaloid From Galanthus Gracilis, Nehi̇r Ünver, Gülen İrem Kaya Jan 2005

An Unusual Pentacyclic Dinitrogenous Alkaloid From Galanthus Gracilis, Nehi̇r Ünver, Gülen İrem Kaya

Turkish Journal of Chemistry

A minor alkaloid, namely gracilamine, was isolated from Galanthus gracilis. This was the first example of a pentacyclic dinitrogenous alkaloid isolated from a member of Amaryllidaceae. The structure of this alkaloid was elucidated by means of comprehensive spectroscopic methods (1D and 2D NMR, MS, UV, IR).

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The Electroanalytical Determination Of Sodium Borohydride Using A Gold Electrode, Hüseyi̇n Çeli̇kkan, Hasan Aydin, M. Levent Aksu Jan 2005

The Electroanalytical Determination Of Sodium Borohydride Using A Gold Electrode, Hüseyi̇n Çeli̇kkan, Hasan Aydin, M. Levent Aksu

Turkish Journal of Chemistry

It was shown that square wave voltammetry, a technique with a much lower detection limit, could be successfully used in the detection of borohydride formed in alkaline medium. A Au electrode was found to be very suitable for this purpose. The detection limit was 3 x 10^{-5} M.

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The Effect Of Silane Modification On The Adsorptive Properties Of Natural Pyrophyllite And Synthetic Titanium-Based Powders Prepared By The Sol-Gel Process, Şadi̇ye Şener, Murat Erdemoğlu, Meltem Asi̇ltürk, Hi̇kmet Sayilkan Jan 2005

The Effect Of Silane Modification On The Adsorptive Properties Of Natural Pyrophyllite And Synthetic Titanium-Based Powders Prepared By The Sol-Gel Process, Şadi̇ye Şener, Murat Erdemoğlu, Meltem Asi̇ltürk, Hi̇kmet Sayilkan

Turkish Journal of Chemistry

Our aim was to improve the relatively poor adsorption characteristics of natural pyrophyllite and those of TiO_m and Ti(OR)_x(OH)_y(O)_z obtained from titanium tetraisopropoxide (TTIP) by the sol-gel process. For this purpose, the surfaces of the above-mentioned adsorbents were coated with a surface modifier by dipping them in 1% and 50% (w/w) solutions of N-(2-aminoethyl)-3- aminopropyltrimethoxysilane (DIAMO) in methanol. Realization of the coating processes was checked by FT-IR and SEM analyses. FT-IR analyses of the coated powders heat treated at 110 °C showed that condensation took place between OH groups of prehydrolyzed silane molecules and hydroxyl groups and/or oxygen atoms on …

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Manganese(Iii) Acetate Mediated Free Radical Cyclization Of 1,3-Dicarbonyl Compounds With Sterically Hindered Olefins, Mehmet Yilmaz, Emre Bi̇çer, A. Tarik Pekel Jan 2005

Manganese(Iii) Acetate Mediated Free Radical Cyclization Of 1,3-Dicarbonyl Compounds With Sterically Hindered Olefins, Mehmet Yilmaz, Emre Bi̇çer, A. Tarik Pekel

Turkish Journal of Chemistry

The manganese(III) acetate mediated radical cyclization of dimedone 1a, 2,4-pentanedione 1b, ethyl acetoacetate 1c, 1,3-cyclohexanedione 1d and 5-phenyl-1,3-cyclohexanedione 1e with 1,1-diphenyl-1-butene 2a afforded 4,5-dihydrofurans (3c, 3e) and tetrahydrobenzofurans (3a, 3g, 3h) in good yields (55% - 77%). Additionally, the reactions of trifluoromethyl-group containing 1,3-dicarbonyls, 4,4,4-trifluoro-1-phenylbutane-1,3-dione 1f and 4,4,4-trifluoro-1-thien-2ylbutane-1,3-dione 1g with 2a 3-trifluoroacetyl-4,5-dihydrofurans gave in 74% and 78% yields, respectively. Treatment of 1a, 1b and 1c with 1,2-diphenyl-1-pentene 2a resulted in the formation of tetrahydrobenzofuran 3b and 4,5-dihydrofurans 3d and 3f in lower yields.

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Spectroscopic And Luminescence Properties Of An Isonicotinic Acid, Nurdoğan Can, Ahmet Ataç, Fehmi̇ Bardak, Şebnem Esen Sözerli̇ Can Jan 2005

Spectroscopic And Luminescence Properties Of An Isonicotinic Acid, Nurdoğan Can, Ahmet Ataç, Fehmi̇ Bardak, Şebnem Esen Sözerli̇ Can

Turkish Journal of Chemistry

An isonicotinic acid N-oxide Zn(II) compound was characterized on the basis of elemental analysis. FTIR spectra of the compound and free isonicotinic acid N-oxide (INO) were recorded in the range 4000--400 cm^{-1}. Cathodoluminescence (CL) spectra from the Zn(INO)_2 complex were recorded. The luminescence data were interpreted in terms of the emission band at 470 nm. The green luminescence (\sim 470 nm) arises from Zn^{2+} transition ^4T_1 (^4G) \to ^6A_1 (^6S). It shows a weak vibronic structure, and short lifetimes less than 150 \mu s. The lifetime and intensity of the signal are temperature dependent, and the parameters are reported for …

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Catalytic Oxidation Properties And Characterization Of Lasrco_{0.9}B'_{0.1}O_4 (B'= Mn, Fe, Ni, Cu) Mixed Oxides, Laitao Luo, Guangxin Shao, Zhanhui Duan Jan 2005

Catalytic Oxidation Properties And Characterization Of Lasrco_{0.9}B'_{0.1}O_4 (B'= Mn, Fe, Ni, Cu) Mixed Oxides, Laitao Luo, Guangxin Shao, Zhanhui Duan

Turkish Journal of Chemistry

Using a polyacrylamide gel method, a series of LaSrCo_{0.9}B'_{0.1}O_4 (B'= Mn, Fe, Ni, Cu) mixed oxides were prepared and their catalytic activity was studied with CO and C_3H_8 oxidations as a testing reaction. The results show that the specific effects of B' ions on CO and C_3H_8 oxidations depend on their category. In comparison to LaSrCoO_4 catalyst, the activity of LaSrCo_{0.9}Ni_{0.1}O_4 catalyst for CO and C_3H_8 oxidations is higher, while only lower activity is obtained for Mn, Fe or Cu-doped catalysts. The information derived from TPD, XRD and iodometry experiments shows that the increase in oxidation activity of LaSrCo_{0.9}Ni_{0.1}O_4 catalyst …

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Synthesis, Characterization And Genotoxicity Of Platinum(Ii)Complexes With Subtituted Benzimidazole Ligands, Özteki̇n Algül, Berri̇n Özçeli̇k, Ufuk Abbasoğlu, Fatma Gümüş Jan 2005

Synthesis, Characterization And Genotoxicity Of Platinum(Ii)Complexes With Subtituted Benzimidazole Ligands, Özteki̇n Algül, Berri̇n Özçeli̇k, Ufuk Abbasoğlu, Fatma Gümüş

Turkish Journal of Chemistry

Five Pt(II) complexes with the ligands 2-ethyl-/ or-benzyl-/ or-phenoxymethyl- and 1-methyl-2-hydroxymethyl- and 1-methyl-2-phenyl- benzimidazoles were synthesized and characterized by elemental analysis, and IR and ^1H-NMR spectra and evaluated for their in vitro genotoxic activities by Rec-Assay test. Based on the data obtained in this study, the Pt(II) complexes tested might be taken into consideration as promising antitumor compounds.

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Interpretation Of Sorption Kinetics For Mixtures Of Reactive Dyes On Wool, Eli̇f Şahi̇n Jan 2005

Interpretation Of Sorption Kinetics For Mixtures Of Reactive Dyes On Wool, Eli̇f Şahi̇n

Turkish Journal of Chemistry

The equilibrium sorption isotherms of 3 reactive dyes (C. I. Reactive Yellow 84, C. I. Reactive Red 141, C. I. Reactive Blue 160) and their binary mixtures adsorbed on prewetted wool fiber were investigated. The kinetic studies were carried out at pH \le 7 and 80 °C in dye solutions containing 20 g/L NaCl. It was reported that binary mixtures of these reactive dyes have lower sorption values than the dyes alone, at the same dye concentration, pH and temperature. The isotherms obtained are Langmuir type. The rate parameters of adsorption kinetics decrease with increasing dye concentration.

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Investigation Of Electron Transfer Reaction Between Diphenylbenzidine And Ascorbic Acid, Iftikhar Imam Naqvi, Abida Perveen Jan 2005

Investigation Of Electron Transfer Reaction Between Diphenylbenzidine And Ascorbic Acid, Iftikhar Imam Naqvi, Abida Perveen

Turkish Journal of Chemistry

The kinetics of the reduction of diphenylbenzidine by ascorbic acid were investigated in the pH range 3.5 to 5.0. Diphenylbenzidine was prepared by the oxidation of diphenylamine with cerium(IV) sulfate tetra hydrate. The order of the reaction with respect to each of the reactants, i.e ascorbic acid (ASC), diphenylbenzidine (DPB) and H^+ ,was found to be first. The following rate law is recommended: Rate = {k_1 [C_{12}H_{10}N_2C_{12}H_{10}] + k_2K [C_{12}H_{10}N_2C_{12}H_{10}][H^+]}[C_6H_8O_6] where k_1 and k_2 have the values of 2.0 \times 10^4 dm^3mol^{-1} s^{-1} and 6.58 \times 10^3 dm^3.mol^{-1}.s^{-1} , respectively. K is the protonation constant of DPB, having a value …

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A New Approach Towards (\Pm)-4-Ipomeanol And Its 2-Furyl Regioisomer, Jurgen Krauss, Franz Bracher, Doris Unterreitmeier Jan 2005

A New Approach Towards (\Pm)-4-Ipomeanol And Its 2-Furyl Regioisomer, Jurgen Krauss, Franz Bracher, Doris Unterreitmeier

Turkish Journal of Chemistry

The cytotoxic furan derivative (\pm)-4-ipomeanol (1) and its regioisomer (8) were prepared in a new and efficient way starting from commercially available furan derivatives. In both cases the key step was a regioselective solvolysis of the terminal double bond with trifluoroacetic anhydride and boron trifluoride. The resulting compounds were tested in an agar diffusion assay against several bacteria and fungi, but did not show significant activity.

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Synthesis Of 2-[2-(3,4,5-Trimethoxybenzoyloxy)Ethyl]Pyrrolidine Hydrochloride Controlled By Gc-Ms, ^1h And ^{13}C Nmr Analyses, Alicja Wodnicka, Malgorzata Dzieciol Jan 2005

Synthesis Of 2-[2-(3,4,5-Trimethoxybenzoyloxy)Ethyl]Pyrrolidine Hydrochloride Controlled By Gc-Ms, ^1h And ^{13}C Nmr Analyses, Alicja Wodnicka, Malgorzata Dzieciol

Turkish Journal of Chemistry

The synthesis of 2-[2-(3,4,5-trimethoxybenzoyloxy)ethyl]pyrrolidine hydrochloride was performed using 2-(2-hydroxyethyl)pyrrolidine as a starting material. Before the O-acylation reaction with 3,4,5-trimethoxybenzoyl chloride, the amino group was protected using benzyl chlorocarbonate. The removal of the blocking group was carried out in modified conditions, avoiding the alcoholysis of the ester bond. The final product was separated from its structural isomer by precipitation as its hydrochloride salt. Some steps of the synthesis were controlled by GC-MS. The identification of the respective compounds was performed by mass spectra analyses and confirmed by ^1H NMR, ^{13}C NMR, IR and elemental analyses.

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