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Articles 26791 - 26820 of 34732

Full-Text Articles in Physical Sciences and Mathematics

Spectrophotometric Study Of The Interaction Between Aza-15-Crown-5 And Some \Pi-Acceptors In Chloroform Solution, H. R. Pouretedal, A. Semnani, Mohammad Hossein Keshavarz, A. Firooz Jan 2005

Spectrophotometric Study Of The Interaction Between Aza-15-Crown-5 And Some \Pi-Acceptors In Chloroform Solution, H. R. Pouretedal, A. Semnani, Mohammad Hossein Keshavarz, A. Firooz

Turkish Journal of Chemistry

A spectrophotometric study concerning the interaction between A15C5 as n-donor and TCNE, DDQ, TCNQ and bromanil as \pi -acceptor was been performed in chloroform at 25 °C. The results of TCNE indicate the formation of a 1:1 charge-transfer complex through a nonequilibrium reaction. In the case of DDQ, the formation of 1:2 (A15C5/DDQ) and 1:1 charge-transfer complexes through equilibrium and nonequilibrium reactions is confirmed. The formation constant of the equilibrium step was evaluated from the computer fitting of the absorbance-mole ratio data as logK_f = 5.14 \pm 0.09. The [A15C5^+ (DDQ)_2^- ] and [A15C5^+DDQ^- ] are suggested as the possible …

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Heterogeneous Electron Transfer Rate Constants Of Viologen At A Platinum Disk Electrode, Naheed Kaukab Bhatti, M. Sadiq Subhani, Ather Yaseen Khan, Rumana Qureshi, Abdur Rahman Jan 2005

Heterogeneous Electron Transfer Rate Constants Of Viologen At A Platinum Disk Electrode, Naheed Kaukab Bhatti, M. Sadiq Subhani, Ather Yaseen Khan, Rumana Qureshi, Abdur Rahman

Turkish Journal of Chemistry

The transfer of electrons to the dications of viologens including methyl viologen, diquat, benzyl viologen and n-butyl viologen was studied at the surface of a platinum disk electrode. The rate constants for the processes were determined and the effects of solvent, temperature and working electrode studied. The studies showed that the rate constants increase with temperature and the effect of solvent on the heterogeneous electron transfer rate constant is related to the polarity, dielectric constant and viscosity of the solvent and on the electrode material. Theoretical rate constants were calculated by considering the effects of barrier crossing probability and nuclear-frequency …

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Extraction-Spectrophotometric Determination Of Trace Amounts Of Barium And Strontium By 18-Crown-6 And Rose Bengal Using Partial Least Squares, Jahan B. Ghasemi, Alireza Nikrahi, Ali Niazi Jan 2005

Extraction-Spectrophotometric Determination Of Trace Amounts Of Barium And Strontium By 18-Crown-6 And Rose Bengal Using Partial Least Squares, Jahan B. Ghasemi, Alireza Nikrahi, Ali Niazi

Turkish Journal of Chemistry

Partial least squares modeling is a powerful multivariate statistical tool applied to extraction-spectrophotometric simultaneous determination of mixtures of barium and strontium. The method is based on the formation of the ternary complexes with 18C6 and rose bengal with barium and strontium. The 18C6-Ba-RB and 18C6-Sr-RB ternary complexes are quantitatively extracted into dichloromethane and the resolution of the mixtures is accomplished by partial least squares (PLS). In this study, the calibration model is based on absorption spectra in the 500-600 nm range for 25 different mixtures of barium and strontium. Calibration matrice's ranges were 0.05-5.50 and 0.03-4.50 \mu g mL^{-1} and …

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Reactions Of Alkenes With Sodium Perborate And Sodium Chloride, Erdal Şenocak, Yavuz Taşkesengi̇l, Ferhan Tümer, Cavi̇t Kazaz Jan 2005

Reactions Of Alkenes With Sodium Perborate And Sodium Chloride, Erdal Şenocak, Yavuz Taşkesengi̇l, Ferhan Tümer, Cavi̇t Kazaz

Turkish Journal of Chemistry

Sodium perborate oxidatively chlorinates a variety of alkenes with sodium chloride to form the corresponding chloro derivatives under mild conditions.

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Construction And Characterization Of Indium Liquid Ion Selective Electrodes Based On Crown Ethers In A Pvc Matrix Membrane, Najwa I. Abdulla, Abdul-Muhsin Al-Haideri, Moen I. Al-Joboury, Nabil S. Nassory Jan 2005

Construction And Characterization Of Indium Liquid Ion Selective Electrodes Based On Crown Ethers In A Pvc Matrix Membrane, Najwa I. Abdulla, Abdul-Muhsin Al-Haideri, Moen I. Al-Joboury, Nabil S. Nassory

Turkish Journal of Chemistry

Several indium ion selective electrodes were constructed based on 15-crown-5 (15C5), dicyclohexano-18-crown-6 (DCH18C6) and dibenzo-24-crown-8 (DB24C8) as sensors and di-octyl phenyl phosphonate (DOPP), di-butyl phthalate (DBPH), tri-butyl phosphate (DBP), tri-n-amyl phosphate (TAP) and bis (2-ethyl hexyl) phosphate (BEHP) as plasticizers in a PVC matrix membrane. Electrode parameters, pH effect and interferences were also studied. The indium electrode based on 15C5 using DOPP as a plasticizer gave the best response for low levels of In^{3+} ions. The linear range for this electrode ranged from 3.8 x 10^{-5} to 5.0 x 10^{-2} M (with correlation coefficient r = 0.9997), the slope was …

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Characterization Of Tio_2 Synthesized In Alcohol By A Sol-Gel Process: The Effects Of Annealing Temperature And Acid Catalyst, Funda Sayilkan, Meltem Asi̇ltürk, Hi̇kmet Sayilkan, Yunus Önal, Murat Akarsu, Ertuğrul Arpaç Jan 2005

Characterization Of Tio_2 Synthesized In Alcohol By A Sol-Gel Process: The Effects Of Annealing Temperature And Acid Catalyst, Funda Sayilkan, Meltem Asi̇ltürk, Hi̇kmet Sayilkan, Yunus Önal, Murat Akarsu, Ertuğrul Arpaç

Turkish Journal of Chemistry

The effects of annealing temperature and hydrolysis catalyst on the crystalline form and crystallite size of TiO_2 prepared by a sol-gel process were investigated. Three types of TiO_2 were synthesized by hydrolysis of titanium(IV)-iso-propoxide with water in n-propanol without catalyst (Type-A) and with HCl as catalyst, where the H^+ /Ti^{4+} mol ratio was 0.54 for Type-B and 0.2 for Type-C. Hydrolysis products were thermally treated at 100, 200, 300, 400 and 500 °C for 1 h after drying at room temperature. Characterization of the particles was carried out using XRD, BET, TG/DTA and SEM analysis. The pore size distributions were …

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Crystal Structure Of The Cis-Bis[4-Chloro-N-(Pyrrolidine-1-Carbothioyl)-Benzamido] Copper(Ii) Complex, Nevzat Külcü, Ulrich Flörke, Hakan Arslan Jan 2005

Crystal Structure Of The Cis-Bis[4-Chloro-N-(Pyrrolidine-1-Carbothioyl)-Benzamido] Copper(Ii) Complex, Nevzat Külcü, Ulrich Flörke, Hakan Arslan

Turkish Journal of Chemistry

The crystal and molecular structure of the cis-bis[4-chloro-N-(pyrrolidine-1-carbothioyl)-benzamido] copper(II) complex was determined by single-crystal X-ray diffraction. The title compound, C_{24}H_{24}N_4O_2 S_2Cl_2Cu, crystalizes in the triclinic space group P-1, with Z = 4 and unit cell parameters a = 8.3877(5) Å, b = 12.7904(8) Å, c = 24.160(2) Å, \alpha = 95.923(1) °, \beta = 96.001(1) °, and \gamma = 95.048(1) °. The copper atom is 4-fold coordinated by 2 S and 2 O atoms and shows a slightly distorted planar quadratic ligand arrangement.

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Diels-Alder Reactions Of New Methoxysubstituted-6-Arylfulvenes, Nüket Öcal, Emi̇ne Bağdatli, Mesut Arslan Jan 2005

Diels-Alder Reactions Of New Methoxysubstituted-6-Arylfulvenes, Nüket Öcal, Emi̇ne Bağdatli, Mesut Arslan

Turkish Journal of Chemistry

Fulvenes 1, 2 and 3 were prepared and their Diels-Alder cycloaddition reactions with maleic anhydride, N-phenylmaleimide and dimethyl acetylenedicarboxylate (DMAD) as dienophiles leading to endo- and exo- [4+2] adducts shown.

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Determination Of Trace Copper By Faas After Solid Phase Extraction And Preconcentration Onto Amberlite Xad-2 Loaded With Nitroso-R Salt, Mohammad Ali Taher, Sayed Ziae Mohammadi Mobarakeh, Ali Reza Mohadesi Jan 2005

Determination Of Trace Copper By Faas After Solid Phase Extraction And Preconcentration Onto Amberlite Xad-2 Loaded With Nitroso-R Salt, Mohammad Ali Taher, Sayed Ziae Mohammadi Mobarakeh, Ali Reza Mohadesi

Turkish Journal of Chemistry

A procedure for the separation and preconcentration of trace amounts of copper is proposed. It is based on the adsorption of copper(II) ions solution onto a column of Amberlite XAD-2 resin loaded with disodium 1-nitroso-2-naphthol-3, 6-disulfonate (nitroso-R salt). Copper is quantitatively retained on the column in the pH range 5.5-7.8 at a flow rate of 2 mL min^{-1}. The copper complex eluted with 5 mL of dimethylformamide (DMF) and copper was measured by flame atomic absorption spectrometry (FAAS) at 324.8 nm. In this case, 0.10 \mu g of copper can be concentrated in the column from 800 mL of aqueous …

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Development And Characterization Of A Cationic Emulsion Formulation As A Potential Pdna Carrier System, Kudret Di̇lşat Barut, Fatma Fi̇li̇z Coşkun Ari, Fi̇li̇z Öner Jan 2005

Development And Characterization Of A Cationic Emulsion Formulation As A Potential Pdna Carrier System, Kudret Di̇lşat Barut, Fatma Fi̇li̇z Coşkun Ari, Fi̇li̇z Öner

Turkish Journal of Chemistry

The development of efficient and stable carriers for the delivery of DNA to the body is becoming an increasingly important issue in the fields of gene therapy and vaccination. The present study was designed to prepare an emulsion-based gene delivery system. Oil-in-water emulsions containing cetyltrimethylammonium bromide (CTAB) as a cationic surfactant and Pluronic F-68 as a nonionic co-surfactant were formulated and their physical characteristics were investigated. The cationic emulsion, referred to as B13d, containing a liquid crystal phase, was found to be stable and suitable for parenteral application. Complex formation between pGL3 plasmid DNA and B13d emulsion achieved at the …

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Potentiometric Studies On The Protonation Constants And Solvation Of Some \Alpha-Amino Acid Benzyl- And T-Butyl- Esters In Ethanol-Water Mixtures, Alev Doğan, Esma Kiliç Jan 2005

Potentiometric Studies On The Protonation Constants And Solvation Of Some \Alpha-Amino Acid Benzyl- And T-Butyl- Esters In Ethanol-Water Mixtures, Alev Doğan, Esma Kiliç

Turkish Journal of Chemistry

To gain more information about the effect of solvent on \alpha -amino acid benzyl- and t-butyl- esters, the stoichiometric protonation constants of 10 esters (glycine benzyl ester, L-alanine benzyl ester, L-valine benzyl ester, L-serine benzyl ester, glycine t-butyl ester, L-alanine t-butyl ester, L-valine t-butyl ester, L-leucine t-butyl ester, L-phenylalanine t-butyl ester and L-isoleucine t-butyl ester) in 20%-80% (v/v) ethanol-water mixtures were determined at an ionic strength of 0.10 M NaCl and at 25.0 \pm 0.1 °C under nitrogen atmosphere. A potentiometric method was used and the calculation of constants was carried out using the PKAS computer program. The logarithm of …

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Synthesis And Characterization Of Novel Hyperbranched Polyimides Based On Silsesquioxane Nanocomposite Networks, Turgay Seçki̇n, Ahmet Gültek, Süleyman Köytepe Jan 2005

Synthesis And Characterization Of Novel Hyperbranched Polyimides Based On Silsesquioxane Nanocomposite Networks, Turgay Seçki̇n, Ahmet Gültek, Süleyman Köytepe

Turkish Journal of Chemistry

A series of nanosized polyimides was successfully prepared by condensation polymerization of an octaamino-functionalized silsesquioxane and a series of commercially available dianhyride monomers. The polymerization of the octaamino silsesquioxane was carried out in 1-methyl-2-pyrrolidone (NMP) at room temperature, giving poly(amic acid) as precursor polymers that were readily converted to the corresponding polyimides by thermal treatment in the subsequent step, which is similar to the conventional 2-stage method. The appropriate molar ratio of the silsesquioxane monomer to a dianhyride was 1:1. These polyimides are readily soluble in polar aprotic solvents such as 1-methyl-2-pyrrolidone, and N,N-dimethylacetamide at room temperature, and show high …

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Kaurane Diterpenoids From Three Sideritis Species, Maurizio Bruno, Franco Piozzi, Nelly Apostolides Arnold, K. Hüsnü Can Başer, Nurhayat Tabanca, Neşe Kirimer Jan 2005

Kaurane Diterpenoids From Three Sideritis Species, Maurizio Bruno, Franco Piozzi, Nelly Apostolides Arnold, K. Hüsnü Can Başer, Nurhayat Tabanca, Neşe Kirimer

Turkish Journal of Chemistry

Some kaurane diterpenoids were isolated from 3 species of the genus Sideritis (Lamiaceae) growing in the Eastern Mediterranean region. Sideritis libanotica subsp. libanotica contained siderol 2 and sideridiol 3. Sideritis erythrantha var. erythrantha yielded sideridiol 3. Sideritis perfoliata gave siderol 2, sideridiol 3 and sideritriol 4. The products are known as they occur in another species of Sideritis growing in Italy and in other species growing also in Turkey. The products are isolated for the first time from these 3 species. The taxonomic significance of these results is discussed.

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Flavonoids From The Leaves Of Impatiens Bicolor, Aurangzeb Hasan, Muhammad Nawaz Tahir Jan 2005

Flavonoids From The Leaves Of Impatiens Bicolor, Aurangzeb Hasan, Muhammad Nawaz Tahir

Turkish Journal of Chemistry

Three new flavanone glycosides, naringenin 4'-O-\beta-D-glucuronopyranoside, naringenin 4'-O-\alpha-L rham\-nopyranoside and naringenin 4'-O-\beta-D-xylopyranoside, were characterized from the leaves of Impatiens bicolor, together with 6 known glycosides: naringenin 4'-O-\beta-D-glucopyranoside, kaempferol 7-O-\beta-D-glucuronopyranoside, quercetin 3-O-\beta-D-glucopyranoside, kaempferol 5-O-\beta-D-xylopyranoside, kaempferol 3-O-\beta-D-galactopyranoside and kaempferol 7-O-\beta-D-xylopyranoside. The structures were determined by means of co-chromatography, UV, HPLC, EI-MS, FAB-MS and ^1H NMR.

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Secondary Metabolites Of Phlomis Viscosa And Their Biological Activities, İhsan Çaliş, Hasan Kirmizibekmez, John A. Beutler, Ali̇ Arslan Dönmez, Funda Nuray Yalçin, Ekrem Kiliç, Meral Özalp, Peter Rüedi, Deni̇z Taşdemi̇r Jan 2005

Secondary Metabolites Of Phlomis Viscosa And Their Biological Activities, İhsan Çaliş, Hasan Kirmizibekmez, John A. Beutler, Ali̇ Arslan Dönmez, Funda Nuray Yalçin, Ekrem Kiliç, Meral Özalp, Peter Rüedi, Deni̇z Taşdemi̇r

Turkish Journal of Chemistry

Further phytochemical studies on the aerial parts of Phlomis viscosa (Lamiaceae) led to the isolation of 24 compounds: 3 iridoid glycosides, 10 phenylethanoid glycosides, a megastigmane glycoside and a hydroquinone glycoside, as well as 2 lignan glucosides and 7 neolignan glucosides, 1 of which is new (17b). Compound 17b was obtained as a minor component of an inseparable mixture (2:1) of 2 neolignan glucosides (17a/b), and characterized as 3',4-O-dimethylcedrusin 9-O-\beta -glucopyranoside. Full NMR data of the known 8-O-4' neolignan glucoside, erythro-1-(4-O-\beta-glucopyranosyl-3-methoxyphenyl)- 2-{2-methoxyl-4-[1-(E)-propene-3-ol]-phenoxyl}-propane-1,3-diol (18) are also reported. All isolated compounds were screened for cell growth inhibition versus 3 tumor cell lines …

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The Synthesis And Applications Of Cr-Doped Glymo And Glymo/Damo Surface Coating Systems For Absorbing Uv-Light By Sol-Gel Process, Meltem Asi̇ltürk, Funda Sayilkan, Gali̇p İçduygu, Hi̇kmet Sayilkan Jan 2005

The Synthesis And Applications Of Cr-Doped Glymo And Glymo/Damo Surface Coating Systems For Absorbing Uv-Light By Sol-Gel Process, Meltem Asi̇ltürk, Funda Sayilkan, Gali̇p İçduygu, Hi̇kmet Sayilkan

Turkish Journal of Chemistry

A new glass coating system, containing \gamma- glycidoxypropyltrimethoxysilane/Cr^{3+} (system I:GLYMO/ Cr^{3+}) and \gamma-glycidoxypropyltrimethoxysilane/N-aminoethyl-3- aminopropyltrimethoxysilane/Cr^{3+} (system II:GLYMO/DAMO/Cr^{3+}), was synthesized by the sol-gel technique for UV light absorption applications. UV-visible spectroscopy (UV-VIS) was utilized to investigate the optical properties of coating materials. Especially system II showed very low transmission in the UV wavelength regions (300--400 nm) after thermal treatment of the coated surface. The UV transmission property of surfaces did not change at 80, 100, 450 or 500 °C, but a T value as low as 0.07% was obtained between 150 and 450 °C.

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Kinetics Study Of Lead Ion Adsorption On Active Carbon, Riaz Qadeer, Sohail Akhtar Jan 2005

Kinetics Study Of Lead Ion Adsorption On Active Carbon, Riaz Qadeer, Sohail Akhtar

Turkish Journal of Chemistry

The kinetics of the adsorption of lead ions on active carbon from aqueous solutions was studied at room temperature at different lead ion concentrations (i.e. 0.1-0.5 g/L). The kinetics of the lead ion adsorption on active carbon is explained through mass transfer adsorption phenomena and the rate determining step was found to be film diffusion

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Cobalt Impregnated Alumina: Nitrogen Adsorption Study At 77 K, Riaz Qadeer, Sumeera Ikram Jan 2005

Cobalt Impregnated Alumina: Nitrogen Adsorption Study At 77 K, Riaz Qadeer, Sumeera Ikram

Turkish Journal of Chemistry

Alumina powder is impregnated with cobalt in the concentration range 5% to 20% (w/v) and is characterized by nitrogen adsorption at 77 K by continuous flow method using the Quantasorb sorption system. It was observed that cobalt metal on impregnation does not contribute any extra surface to alumina. Values of BET surface area determined from nitrogen adsorption data follow the sequence Co (20% w/v) - Al_2O_3 < Co (10% w/v) - Al_2O_3 < Co (5% w/v) - Al_2O_3 < Pure Al_2O_3. Pore size distribution curves demonstrate the mesoporous nature of cobalt impregnated alumina.

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Synthesis And Complex Formation Of Some Novel Vic-Dioxime Derivatives Of Hydrazones, Nursabah Sarikavakli, Gazi̇ İrez Jan 2005

Synthesis And Complex Formation Of Some Novel Vic-Dioxime Derivatives Of Hydrazones, Nursabah Sarikavakli, Gazi̇ İrez

Turkish Journal of Chemistry

Three novel vic-dioxime compounds and their transition metal complexes were synthesized for the first time. These ligands are anti-glyoximehydrazine (GH_2), anti-2-pyridinealdehydeglyoxime hydrazone (PyGH_2) and anti-2-furancarboxaldehydeglyoxime hydrazone (FGH_2). The synthesized anti-glyoximehydrazine was reacted with 2-pyridinealdehyde or 2-furancarboxaldehyde to obtain the PyGH_2 and FGH_2 ligands. Mononuclear complexes of these ligands with a metal-ligand ratio of 1:2 were prepared with Ni(II), Co(II) and Cu(II) ions. The structures of the ligands and complexes were determined by ^1H n.m.r, i.r spectroscopy and elemental analytical techniques.

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Anhydrous Proton Conductive Polystyrene Sulfonic Acid Membranes, Ayhan Bozkurt Jan 2005

Anhydrous Proton Conductive Polystyrene Sulfonic Acid Membranes, Ayhan Bozkurt

Turkish Journal of Chemistry

A novel anhydrous proton conducting polymer electrolyte based on polystyrene sulfonic acid, PSSA and benzimidazole (BnIm) was synthesized. The PSSA-BnIm interactions were studied by FT-IR. The thermal properties of the blends were investigated by thermogravimetric analysis (TG) and differential scanning calorimetry (DSC). The proton conductivities of these materials were measured by AC impedance technique. The conductivities of these materials increase with increasing BnIm content and temperature and maximum conductivity was found to be approximately 5 \times 10^{-4} S/cm at 150 °C.

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Synthesis And Characterization Of New Triheterocyclic Compounds Consisting Of 1,2,4-Triazol-3-One, 1,3,4-Thiadiazole And 1,3,4-Oxadiazole Rings, Nesli̇han Demi̇rbaş Jan 2005

Synthesis And Characterization Of New Triheterocyclic Compounds Consisting Of 1,2,4-Triazol-3-One, 1,3,4-Thiadiazole And 1,3,4-Oxadiazole Rings, Nesli̇han Demi̇rbaş

Turkish Journal of Chemistry

A series of acetic acid derivatives (2a-c) was synthesized by the condensation of compounds 1a-c with chloroacetic acid. The treatment of carboxylic acid derivatives with thiosemicarbazide in phosphorus oxychloride and subsequent diazotation of the products (3a-c) afforded 5-alkyl-2-[(5-chloro-1,3,4-thiadiazol-2-yl)methyl]- 2,4-dihydro-3H-1,2,4-triazol-3-one derivatives (4a-c). The treatment of compounds 4a-c with thiourea produced 5-alkyl-2-[(5-mercapto-1,3,4- thiadiazol-2-yl)methyl]-2,4-dihydro-3H-1,2,4-triazol-3-one derivatives (5a-c). Subsequently, compounds 5a-c were converted to acid hydrazides by treatment with hydrazine hydrate after esterification (7a-e). Moreover, the reaction of compounds 7a-c with carbon disulfite in the presence of KOH afforded 5-alkyl-2-[(5-\{[(5- mercapto-1,3,4-oxadiazol-2-yl)methyl]thio\}-1,3,4-thiadiazol-2-yl)methyl]- 2,4-dihydro-3H-1,2,4-triazol-3-ones (8a-c).

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Color Reaction Of 2-(2-Quinolylazo)-5-Dimethylaminoaniline With Palladium And Its Application, Yunsen Si, Qiufen Hu, Zhangjie Huang, Guangyu Yang, Jiayuan Yin Jan 2005

Color Reaction Of 2-(2-Quinolylazo)-5-Dimethylaminoaniline With Palladium And Its Application, Yunsen Si, Qiufen Hu, Zhangjie Huang, Guangyu Yang, Jiayuan Yin

Turkish Journal of Chemistry

A new chromogenic reagent, 2-(2-quinolylazo)-5-dimethylaminoaniline (QADMAA) was synthesized. A sensitive, selective and rapid method for the determination of palladium based on the rapid reaction of palladium(II) with QADMAA was developed. In the presence of 0.5-2.5 mol L^{-1} of hydrochloric acid solution and cetyl trimethylammonium bromide medium QADMAA reacts with palladium to form a violet complex with a molar ratio of 1:2 (palladium to QADMAA). The molar absorptivity of the chelate is 1.35x10^5 L mol^{-1} cm^{-1} at 600 nm. Beer's law is obeyed in the range of 0.01 to 0.6 \mu g mL^{-1}. The detection limit is 1.2 \mu g L^{-1}. …

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The Atomic Absorption Spectrophotometric Method For Indirect Determination Of Nimodipine In Tablets, Mevlüde Canlica, Sezen İsli̇myeli̇ Jan 2005

The Atomic Absorption Spectrophotometric Method For Indirect Determination Of Nimodipine In Tablets, Mevlüde Canlica, Sezen İsli̇myeli̇

Turkish Journal of Chemistry

A simple indirect atomic absorption spectrophotometric (AAS) method is described for the analysis of nimodipine in tablet formulations. The method is based on the reduction of the antihypertensive drug substances including an aromatic nitro group by boiling them with cadmium metal in 0.05 N HC??l medium under CO_2 atmosphere for 1 h under reflux. The amounts of the drugs were calculated by determining the atomic absorbances of the released Cd^{+2}. The calibration graphs were plotted between the absorbance Cd^{+2} concentrations in the range of 0.242 to 1.209 \mu g.cm^{-3} for nimodipine. As a reference method, the spectrophotometric procedure was developed. …

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Synthesis Of Some New Isoxazolidines By 1,3-Dipolar Cycloaddition Reaction Of Nitrones And Olefins, Akbar Mobinikhaledi, Naser Forughifar, Zahra Kalate Jan 2005

Synthesis Of Some New Isoxazolidines By 1,3-Dipolar Cycloaddition Reaction Of Nitrones And Olefins, Akbar Mobinikhaledi, Naser Forughifar, Zahra Kalate

Turkish Journal of Chemistry

A series of new isoxazolidines 5a-j were synthesized by 1,3-dipolar cycloaddition reaction of different nitrones with substituted olefins under reflux condition. The yields of products following recrystallization from absolute ethanol were of the order of 40%-66%. IR, NMR and mass spectroscopies were used for identification of these compounds.

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Synthesis And Antimicrobial Evaluation Of Some New 2-(2-(P-Chlorophenyl) Benzimidazol-1-Yl Methyl)-5-Substituted Amino-[1,3,4]-Thiadiazoles, Gülgün Ayhan Kilcigi̇l, Canan Kuş, Nurten Altanlar, Süheyla Özbey Jan 2005

Synthesis And Antimicrobial Evaluation Of Some New 2-(2-(P-Chlorophenyl) Benzimidazol-1-Yl Methyl)-5-Substituted Amino-[1,3,4]-Thiadiazoles, Gülgün Ayhan Kilcigi̇l, Canan Kuş, Nurten Altanlar, Süheyla Özbey

Turkish Journal of Chemistry

Some 2-(2-(p-chlorophenyl)benzimidazol-1-ylmethyl)-5-substituted amino-[1,3,4]-thiadiazoles were synthesized and their in vitro antimicrobial activities were tested against Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Candida albicans and Candida krusei. Compounds 1b and 12b which possess remarkable activity against C. albicans and marginal activity against C. krusei were found to be the most active compounds in this series. Single crystal X-ray diffraction analysis was performed for compound 8b.

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Flavonol Glycosides From Asperula Arvensis L., Zühal Güvenalp, L. Ömür Demi̇rezer Jan 2005

Flavonol Glycosides From Asperula Arvensis L., Zühal Güvenalp, L. Ömür Demi̇rezer

Turkish Journal of Chemistry

From the aerial parts of Asperula arvensis L. 9 known flavonol glycosides, namely quercetin (1), isoquercitrin [= quercetin 3-O-\beta-glucopyranoside] (2), hyperin [= quercetin 3-O-\beta -galactopyranoside] (3), quercetin 7-O-\beta-galactopyranoside (4), quercetin 4'-O-\beta-galactopyranoside (5), isorhamnetin 3-O-\beta -galactopyranoside (6), isorhamnetin 5-O-\beta-galactopyranoside (7), dihydrokaempferol 7-4'-dimethylether 3-O-\beta -glucopyranoside (8) and isorhamnetin 3-O-\alpha -rhamnopyranosyl (1''' \to 6'')-\beta -glucopyranosid (9), were isolated. The structures of the compounds were elucidated by high field 1D and 2D NMR and ESI-MS spectroscopies.

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Synthesis Of Some Novel Optically Active Isocoumarin And 3,4-Dihydroisocoumarin Containing L-Valine And L-Leucine Moieties, Khosrow Zamani, Khalil Faghihi, Satar Ebrahimi Jan 2005

Synthesis Of Some Novel Optically Active Isocoumarin And 3,4-Dihydroisocoumarin Containing L-Valine And L-Leucine Moieties, Khosrow Zamani, Khalil Faghihi, Satar Ebrahimi

Turkish Journal of Chemistry

Phthalic anhydride was reacted with L-Valine and L-Leucine in a mixture of acetic acid and pyridine at room temperature, and then was refluxed at 90-100 °C and N-phthaloyl-L-valine or N-phthaloyl-L-leucine were obtained in quantitative yields. The imide-acids were converted to N-phthaloyl-L-valine acid chloride and N-phthaloyl-L-leucine acid chloride by reaction with thionyl chloride. Then 2 new derivatives of the chiral isocoumarin with L-valine and L-leucine moieties were synthesised by the condensation reaction of homophthalic acid with respective imide-acid chloride. Furthermore these isocoumarins were converted to 2 new chiral substituted 3,4-dihydroisocoumarins. Biological screening tests reveal that the compounds (3a, 9a) have not …

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Terpenoids And Steroids From The Roots Of Salvia Blepharochlaena, Ufuk Kolak, Gülaçti Topçu, Seher Bi̇rteksöz, Gülten Ötük, Ayhan Ulubelen Jan 2005

Terpenoids And Steroids From The Roots Of Salvia Blepharochlaena, Ufuk Kolak, Gülaçti Topçu, Seher Bi̇rteksöz, Gülten Ötük, Ayhan Ulubelen

Turkish Journal of Chemistry

From the roots of Salvia blepharochlaena Hedge and Hub. Mor. 4 triterpenoids, 4 steroids, 6 diterpenoids, and an aromatic ester were isolated. The structures of these compounds were established by spectroscopic methods. Formosanolide was isolated for the first time from the genus Salvia.

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Synthesis And Antimicrobial Activities Of Some New Flavonyl Pro-Drug Esters Of Ampicillin, Meltem Ceylan Ünlüsoy, Nurten Altanlar, Rahmi̇ye Ertan Jan 2005

Synthesis And Antimicrobial Activities Of Some New Flavonyl Pro-Drug Esters Of Ampicillin, Meltem Ceylan Ünlüsoy, Nurten Altanlar, Rahmi̇ye Ertan

Turkish Journal of Chemistry

A new series of flavonyl pro-drug esters of ampicillin (Va-b) was prepared by condensing the appropriate bromomethyl flavone with ampicillin trihydrate potassium salt. Flavone derivatives and ampicillin both have good antibacterial activity. The synthesized compounds were tested for their antifungal and antibacterial activities in vitro. Both of the compounds were active against Candida krusei and Staphylococcus aureus.

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Synthesis And Structural Characterization Of The 2-[(O-Pyridyl)-Sulfanylmethyl]-Pyrimidine-Silver(I) Complex [Ag_2(Opsp)_2](No_3)_2, Li-Rong Wen, Ming Li, Gui-Long Zhao, Xue-Mei Li, Ou-Yang Pingkai, Shu-Sheng Zhang Jan 2005

Synthesis And Structural Characterization Of The 2-[(O-Pyridyl)-Sulfanylmethyl]-Pyrimidine-Silver(I) Complex [Ag_2(Opsp)_2](No_3)_2, Li-Rong Wen, Ming Li, Gui-Long Zhao, Xue-Mei Li, Ou-Yang Pingkai, Shu-Sheng Zhang

Turkish Journal of Chemistry

The new silver(I) complexe [Ag_2(opsp)_2](NO_3)_2 (1) was synthesized by the self-assembly of AgX (X = NO_3^-) with the versatile multidentate ligand opsp (opsp = 2-[(o-pyridyl)-sulfanylmethyl]- pyrimidine). X-ray single-crystal diffraction analyses show that 1 is dinuclear molecule. In 1, 1 opsp ligand acts in a bidentate mode with 2 nitrogen atoms from a pyridine ring and a pyrimidine ring coordinating to 2 Ag(I) atoms, and the Ag(I) center is 2-coordinated by 2 nitrogen atoms showing linear coordination geometry.

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