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2005

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Articles 361 - 390 of 562

Full-Text Articles in Chemistry

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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A Concise Synthesis And The Antibacterial Activity Of 5,6-Dimethoxynaphthalene-2-Carboxylic Acid, Süleyman Göksu, Meti̇n Tansu Uğuz, Hasan Özdemi̇r, Hasan Seçen Jan 2005

A Concise Synthesis And The Antibacterial Activity Of 5,6-Dimethoxynaphthalene-2-Carboxylic Acid, Süleyman Göksu, Meti̇n Tansu Uğuz, Hasan Özdemi̇r, Hasan Seçen

Turkish Journal of Chemistry

5,6-Dimethoxynaphthalene-2-carboxylic acid was synthesized in 7 steps and with an overall yield of 46%. Bromination of 2-naphthol, and methylation with dimethyl sulfate followed by Friedel-Crafts acylation with AcCl gave 2-acetyl-5-bromo-6-methoxynaphthalene. 2-Acetyl-5-bromo-6-methoxynaphthalene was converted to 5-bromo-6- methoxynaphthalene-2-carboxylic acid by a haloform reaction. The esterification of the acid with methanol, methoxylation with NaOCH_3 in the presence of CuI and subsequent de-esterification with NaOH afforded 5,6-dimethoxynaphthalene-2-carboxylic acid. The 5-bromo-6-methoxynaphthalene-2-carboxylic acid and 5,6-dimethoxynaphthalene-2-carboxylic acid were found to have in vitro antibacterial activity against some pathogenic bacteria.

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Synthesis And In Vitro Antimicrobial And Cytotoxicity Activities Of 2-[(2-Nitro-1-Phenylalkyl)Thio]Benzoic Acid Derivatives, Mehtap Gökçe, Semra Utku, Erdoğan Berçi̇n, Berri̇n Özçeli̇k, Taner Karaoğlu, Ni̇ngur Noyanalpan Jan 2005

Synthesis And In Vitro Antimicrobial And Cytotoxicity Activities Of 2-[(2-Nitro-1-Phenylalkyl)Thio]Benzoic Acid Derivatives, Mehtap Gökçe, Semra Utku, Erdoğan Berçi̇n, Berri̇n Özçeli̇k, Taner Karaoğlu, Ni̇ngur Noyanalpan

Turkish Journal of Chemistry

In this research 14 compounds were tested for their antimicrobial activity. The synthesis of 7 compounds corresponding to 2-[(2-nitro-1-phenyl-propyl)thio]benzoic acids 4 has not been reported before and 7 compounds corresponding to 2-[(2-nitro-1-phenyl-ethyl) thio]benzoic acid 3 were reported by our research group. The antibacterial activity of the title compounds was evaluated by 2 Gram (+) (Staphylococcus aureus, Bacillus subtilis) and 2 Gram (-)(Pseudomonas aeruginosa, Escherichia coli) microorganisms. The antifungal activity of the compounds was also determined against yeast-like fungi (Candida albicans, C. krusei). For antibacterial activity, ampicillin and for antifungal activity, fluconazole and ketoconazole have been used as reference compounds. All …

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The Effect Of Metal Loading On Structural Characteristics And Low Temperature Co Oxidation Activity Of Coprecipitated Co/Al_2o_3, Şeyma Özkara, Ayşe Ni̇lgün Akin, Zülal Misirli, Ahmet Erhan Aksoylu Jan 2005

The Effect Of Metal Loading On Structural Characteristics And Low Temperature Co Oxidation Activity Of Coprecipitated Co/Al_2o_3, Şeyma Özkara, Ayşe Ni̇lgün Akin, Zülal Misirli, Ahmet Erhan Aksoylu

Turkish Journal of Chemistry

The effect of metal loading on structural properties and CO oxidation activity of coprecipitated Co/Al_2O_3 catalysts was investigated. The results indicated the participation of cobalt in the Co-Al skeleton for all coprecipitated samples. Environmental-SEM-EDXS studies showed that at loadings higher than ca. 15 wt.-%, cobalt formed layer-by-layer clusters on the surface; 16.8 wt.-% Co/Al_2O_3 displayed the highest activity and stability in CO oxidation.

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Synthesis And Characterization Of Nitrosyl[Tris(3,5dimethylpyrazolyl)Borato]Molybdenum Complexes Containing Aryloxo, Arylamido And Arylcyano Ligands, Işil Topaloğlu Sözüer, Seçki̇ner Dülger İrdem Jan 2005

Synthesis And Characterization Of Nitrosyl[Tris(3,5dimethylpyrazolyl)Borato]Molybdenum Complexes Containing Aryloxo, Arylamido And Arylcyano Ligands, Işil Topaloğlu Sözüer, Seçki̇ner Dülger İrdem

Turkish Journal of Chemistry

The complexes [MoTp*(NO)X(ZC_6H_4CN-p)] [Tp* = 3,5- dimethylpyrazolyl; X = Cl, Z = O and NH; X = I, Z = CN) were prepared and characterized using ^1H-NMR, IR, FAB mass spectroscopy and micro analysis.

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Synthesis, Characterization And Primary Antimicrobial Activity Evaluation Of 3-Phenyl-6-Methyl-4(3h)-Quinazolinone-2-Yl-Mercaptoacetic Acid Arylidenehydrazides, Aysel Gürsoy, Banu Ünal, Ni̇lgün Karali, Gülten Ötük Jan 2005

Synthesis, Characterization And Primary Antimicrobial Activity Evaluation Of 3-Phenyl-6-Methyl-4(3h)-Quinazolinone-2-Yl-Mercaptoacetic Acid Arylidenehydrazides, Aysel Gürsoy, Banu Ünal, Ni̇lgün Karali, Gülten Ötük

Turkish Journal of Chemistry

3-Phenyl-6-methyl-4(3H)-quinazolinone-2-yl-mercaptoacetic acid hydrazide (3) was reacted with substituted aldehydes in absolute ethanol to obtain a new series, 3-phenyl-6-methyl-4(3H)-quinazolinone- 2-yl-mercaptoacetic acid arylidenehydrazides (4a-q). The structures of 4a-q were elucidated by elemental analyses and from spectrometric (UV, IR, ^1H-NMR, ^{13}C-NMR and EIMS) data. Then 4a-q were evaluated for antibacterial, antifungal and antitubercular activities. No significant activity was observed against the selected microorganisms.

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A Novel Method For The Spectrophotometric Determination Of Thallium Using Methiomeprazine Hydrochloride, Hoskere D. Revanasiddappa, Telangusadhushetty N. Kiran Kumar Jan 2005

A Novel Method For The Spectrophotometric Determination Of Thallium Using Methiomeprazine Hydrochloride, Hoskere D. Revanasiddappa, Telangusadhushetty N. Kiran Kumar

Turkish Journal of Chemistry

A new, simple, sensitive, and rapid spectrophotometric method is proposed for the determination of trace amounts of thallium(III). The method is based on the oxidation of methiomeprazine hydrochloride by thallium(III) in phosphoric acid medium to give a blue radical cation, having a maximum absorption at 645 nm. Beer's law is valid over the concentration range 0.5--4.0 \mu g mL^{-1}, with molar absorptivity and Sandell's sensitivity of 3.2 \times 10^4 L mol^{-1} cm^{-1} and 0.0064 \mu g cm^{-2}, respectively. The detection limit of thallium determination is 0.01 \mu g mL^{-1}. The tolerance limits for interfering ions are discussed. All variables were …

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Synthesis And Spectral Investigations Of Some Platinum Metals Ions Coordination Compounds Of 4[N-(Furan-2'-Carboxalidene)Amino]Antipyrine Thiosemicarbazone And 4[N-(3',4',5'-Trimethoxybenzalidene)Amino]Antipyrine Thiosemicarbazone, Ram K. Agarwal, Surendra Prasad Jan 2005

Synthesis And Spectral Investigations Of Some Platinum Metals Ions Coordination Compounds Of 4[N-(Furan-2'-Carboxalidene)Amino]Antipyrine Thiosemicarbazone And 4[N-(3',4',5'-Trimethoxybenzalidene)Amino]Antipyrine Thiosemicarbazone, Ram K. Agarwal, Surendra Prasad

Turkish Journal of Chemistry

The present work describes the synthesis and spectral properties of some platinum metals chlorides coordination compounds of 4[N-(-(furan-2'-carboxalidene)amino]antipyrine thiosemicarbazone (FFAAPTS) and 4[N-(3',4',5'-trimethoxybenzalidene)amino]antipyrine thiosemicarbazone (TMBAAPTS). All the compounds have the general composition MCl_2(L) (M = Pd^{2+} or Pt^{2+} ; L = FFAAPTS or TMBAAPTS) or MCl_3(L) (M = Ru^{3+} , Rh^{3+} or Ir^{3+} ; L = FFAAPTS or TMBAAPTS). All the complexes were characterized by elemental analyses, molar conductance, molecular weight, magnetic measurements, and infrared and electronic spectra. The infrared spectra suggest that both the thiosemicarbazones behave as neutral tridentate (N,N,S) ligands. The magnetic and electronic spectra suggest that Pd^{2+} and …

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Non-Steroidal Anti-Inflammatory Drugs (Nsaids) As Donor Ligands In Organotin(Iv) Derivatives: Synthesis, Spectroscopic Characterization And Biological Applications, Saira Shahzadi, Khadija Shahid, Saqib Ali, Mohammad Mazhar, Amin Badshah, Ejaz Ahmed, Abdul Malik Jan 2005

Non-Steroidal Anti-Inflammatory Drugs (Nsaids) As Donor Ligands In Organotin(Iv) Derivatives: Synthesis, Spectroscopic Characterization And Biological Applications, Saira Shahzadi, Khadija Shahid, Saqib Ali, Mohammad Mazhar, Amin Badshah, Ejaz Ahmed, Abdul Malik

Turkish Journal of Chemistry

Some new di- and tri-organotin(IV) derivatives of 4 different non-steroidal anti-inflammatory drugs (NSAIDs) with the general formulae R_2SnL_2 and R_3SnL (where R = n-C_{8}H_{17} and C_6H_5CH_2) and L = 2-[(2,3-dimethylphenyl)amino]benzoic acid, 2-(2-fluoro-4-biphenyl)propionic acid, 2-(4-isobutylphenyl) propionic acid and 2-(3-benzoylphenyl)-propionic acid were synthesized. These compounds were structurally characterized by infrared and multinuclear NMR (^1H, ^{13}C, ^{119}Sn) spectroscopies and mass spectrometry. The isotopic effect of tin was studied by comparison of experimental data with the simulated isotopic pattern using the Chemtool software package. These compounds were also screened against different animal and plant pathogens to study their biological activity. LD_{50} data show that …

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New Complexes Of Organotin(Iv) 2-(N-Maleoylamino)-2-Methylpropanoate: Synthesis, Spectroscopic Characterization And Biological Activity, Sajjad Ahmad, Saqib Ali, Saira Shahzadi, Fiaz Ahmed, Khalid Mohammed Khan Jan 2005

New Complexes Of Organotin(Iv) 2-(N-Maleoylamino)-2-Methylpropanoate: Synthesis, Spectroscopic Characterization And Biological Activity, Sajjad Ahmad, Saqib Ali, Saira Shahzadi, Fiaz Ahmed, Khalid Mohammed Khan

Turkish Journal of Chemistry

Organotin(IV) complexes of 2-(N-maleoylamino)-2-methylpropanoate were prepared by treating the ligand acid with diorganotin dichloride and triorganotin chloride in 1:2 and 1:1 molar ratios, respectively. These reactions proceeded smoothly to completion and the complexes formed were characterized by elemental analysis, infrared, multinuclear NMR (^1H, ^{13}C, ^{119}Sn) and mass spectrometry. The biological activities of the tin complexes were studied by screening the compounds against various animal and plant pathogens. These results show that triorganotin(IV) carboxylates are more active against the animal and plant pathogens tested as compared to diorganotin dicarboxylates.

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Synthesis, Spectral And Thermal Investigations Of Some Oxovanadium(Iv) Complexes Of Hydrazones Of Isonicotinic Acid Hydrazide, Ram K. Agarwal, Lakshman Singh, Deepak K. Sharma, Ritu Singh Jan 2005

Synthesis, Spectral And Thermal Investigations Of Some Oxovanadium(Iv) Complexes Of Hydrazones Of Isonicotinic Acid Hydrazide, Ram K. Agarwal, Lakshman Singh, Deepak K. Sharma, Ritu Singh

Turkish Journal of Chemistry

A new series of 12 complexes of oxovanadium(IV) with hydrazones of isonicotinic acid hydrazide, namely N-isonicotinamido-3',4',5'-trimethoxybenzalaldimine (INH-TMB) and N-isonicotinamido-2'-furanaldimine (INH-FUR) with the general formula VOX_2.nL (X = Cl, Br, I, NCS, NO_3, n = 1; X = ClO_4, n = 2; L = INH-TMB or INH-FUR) were synthesized and characterized on the basis of analytical, conductance, molecular weight, magnetic moment, infrared and electronic spectral data. The infrared data of the complexes reveal the bidendate nature of both ligands and coordination to carbonyl-oxygen and azomethinic-nitrogen atoms. The probable coordination number of the central metal is 5. Thermal stabilities of the complexes …

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Fast Oxidation Of Lactams To Cyclic Imides Using Microwave Irradiation, Avat Arman Taherpour, Hamid Reza Mansuri Jan 2005

Fast Oxidation Of Lactams To Cyclic Imides Using Microwave Irradiation, Avat Arman Taherpour, Hamid Reza Mansuri

Turkish Journal of Chemistry

Since polar reactants can adsorb microwave irradiation, chemists can utilize the microwave oven for some organic reactions. In this paper, we report a rapid conversion of lactams to cyclic imides using peracetic acid (CH_3-CO_3H) and manganic chloride (MnCl_2) in ethyl acetate (CH_3-COOEt) as a solvent and under microwave irradiation (90 W, 5 min) in good yields.

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Synthesis And Isolation Of New Regioisomeric 4-Thiazolidinones And Their Anticonvulsant Activity, Aysel Gürsoy, Nalan Terzi̇oğlu Jan 2005

Synthesis And Isolation Of New Regioisomeric 4-Thiazolidinones And Their Anticonvulsant Activity, Aysel Gürsoy, Nalan Terzi̇oğlu

Turkish Journal of Chemistry

Two regioisomer series, 2-(3-ethyl-4(3H)-quinazolinone-2- ylmercaptoacetylhydrazono)-3-alkyl/3-aryl-5-methyl-4-thiazolidinones (12-21) and 2-arylimino-3-(3-ethyl-4(3H)-quinazolinone-2-ylmercaptoacetylamino)- 5-methyl-4-thiazolidinones (22-26), were synthesized by the cyclization of 1-(3-ethyl-4(3H)-quinazolinone-2-ylmercaptoacetyl)-4-alkyl/aryl thiosemicarbazides (1-11) with ethyl 2-bromopropionate in the presence of anhydrous sodium acetate in anhydrous ethanolic medium. The structures of 12-26 were confirmed by analytical and spectral data (IR, ^1H-NMR and EIMS). Selected members of the thiosemicarbazides and thiazolidinones were subjected to anticonvulsant activity tests by the National Institute of Neurological Disorders and Stroke MD, USA.

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Synthesis Of Some New Dihalophenyl- And Dihalobenzylisocoumarins And Their (Dl)-3,4-Dihydroderivatives, Zahid Shafiq, Muhammad Arfan, Nasim Hasan Rama, Shahid Hameed, Ghulam Abbas, Muhammad Tahir Hussain Jan 2005

Synthesis Of Some New Dihalophenyl- And Dihalobenzylisocoumarins And Their (Dl)-3,4-Dihydroderivatives, Zahid Shafiq, Muhammad Arfan, Nasim Hasan Rama, Shahid Hameed, Ghulam Abbas, Muhammad Tahir Hussain

Turkish Journal of Chemistry

3-Dihalophenyl- and dihalobenzylisocoumarins (3a-c) were synthesized by condensation of homophthalic acid (1) with dihalobenzoyl- and dihalophenylacetyl chlorides (2a-c), respectively. The alkaline hydrolysis of these isocoumarins (2a-c) afforded keto-acids (4a-c). (dl)-3-(Dihalophenyl)- and (dl)-3-(dihalobenzyl)- 3,4-dihydroisocoumarins (6a-c) were obtained by reduction of keto-acids (4a-c) to racemic hydroxy-acids (5a-c) followed by cyclodehydration using acetic anhydride.

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Pyranocoumarins From Seseli Gummiferum Subsp. Corymbosum Growing In Turkey, Alev Tosun, Nazi̇re Özkal, Masaki Baba, Toru Okuyama Jan 2005

Pyranocoumarins From Seseli Gummiferum Subsp. Corymbosum Growing In Turkey, Alev Tosun, Nazi̇re Özkal, Masaki Baba, Toru Okuyama

Turkish Journal of Chemistry

Seseli gummiferum Pall. ex Sm. subsp. corymbosum (Boiss. & Heldr.) P.H. Davis (Syn: S. corymbosum Boiss. & Heldr.) (Umbelliferae) collected in southern Anatolia was investigated for the presence of coumarins. A new angular-type pyranocoumarin, corymbocoumarin (1), along with 5 known coumarins (2-6) were isolated from the aerial parts of this plant. Corymbocoumarin (1) was established to be (-)-(3'S,4'S)-3' -acetoxy-4'-isovaleryloxy-3',4' -dihydroseselin (1) and coumarins 2-6 were identified as (-)-(3'S,4'S) -3'-acetoxy-4' -angeloyloxy-3' ,4' -dihydroseselin (2), (+)-(3' S,4' S)-3' -hydroxy-4' -angeloyloxy-3', 4' -dihydroseselin (d-laserpitin) (3), (-)-(3' S,4' S)-3' -angeloyloxy-4' -hydroxy-3', 4' -dihydroseselin (4), 3' -acetoxy-4' -isobutyloxy-3', 4' -dihydroseselin (5) and osthole (6), respectively, …

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Determination Of Cadmium, Copper, Iron, Manganese, Lead And Zinc In Lichens And Botanic Samples By Electrothermal And Flame Atomic Absorption Spectrometry, Orhan Acar, Sümer Özvatan, Murat İli̇m Jan 2005

Determination Of Cadmium, Copper, Iron, Manganese, Lead And Zinc In Lichens And Botanic Samples By Electrothermal And Flame Atomic Absorption Spectrometry, Orhan Acar, Sümer Özvatan, Murat İli̇m

Turkish Journal of Chemistry

Within the framework of the International Atomic Energy Agency (IAEA) Analytical Quality Control Service (AQCS) Chemistry Unit a research program was initiated for the identification of trace elements such as Cd, Cu, Fe, Mn, Pb and Zn in IAEA lichen-338 for a proficiency test (PT). This was to evaluate the possibility of using lichens as biomonitors of trace elements in atmospheric pollution. Pyrolysis and atomization temperatures, atomization and background profiles, detection limits and characteristic masses of analytes in lichen samples with Ni, Ni + Pd and Ni + Pd + tartaric acid (TA) modifier mixture, and without any modifiers were …

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Mechanism And Kinetics Of Copper(Ii) Transport Through A Liquid Membrane Containing A Dithiophosphonate Derivative As Carrier, H. Korkmaz Alpoğuz, Ahmet Kaya, Mehmet Karakuş Jan 2005

Mechanism And Kinetics Of Copper(Ii) Transport Through A Liquid Membrane Containing A Dithiophosphonate Derivative As Carrier, H. Korkmaz Alpoğuz, Ahmet Kaya, Mehmet Karakuş

Turkish Journal of Chemistry

The transport of Cu(II) ions from an aqueous solution into an aqueous receiving solution through a bulk liquid membrane containing a dithiophosphonate derivative (1) as a carrier was examined. The kinetic parameters were analyzed assuming 2 consecutive, irreversible first-order reactions. The influence of temperature and stirring rate on the kinetic parameters (k_1, k_2, R_m^{max}, t_{max}, J_d^{max} and J_a^{max}) was also investigated. The membrane entrance rate, k_1, and the membrane exit rate, k_2, increased with increasing temperature and stirring rate. For the maximum membrane exit flux, J_a^{max}, the activation energy was determined from the slope of the linear Arrhenius relationship to …

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Anodic Stripping Voltammetric Behavior Of Mercury In Chloride Medium And Its Determination At A Gold Film Electrode, Füsun Okçu, F. Ni̇l Ertaş, H. İsmet Gökçel, Hüseyi̇n Tural Jan 2005

Anodic Stripping Voltammetric Behavior Of Mercury In Chloride Medium And Its Determination At A Gold Film Electrode, Füsun Okçu, F. Ni̇l Ertaş, H. İsmet Gökçel, Hüseyi̇n Tural

Turkish Journal of Chemistry

The electrochemical behavior of aqueous Hg(II) ions at a gold film electrode is described. The effects of supporting electrolyte and halide ions on the anodic stripping voltammetric behavior of Hg(II) ions was illustrated to prepare a basis for the analysis in real samples with high saline content. The concentration ratio of metallic mercury to halide ions at the electrode surface determines the resulting peak characteristics. The peak potentials in particular shift in a more negative direction as the halide concentration increases. A comparative study with Cu(II) ions revealed that a different mechanism is involved in their reoxidation steps. Mercuric ions …

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Catalytic Spectrophotometric Determination Of Chromium, Angelina Miltcheva Stoyanova Jan 2005

Catalytic Spectrophotometric Determination Of Chromium, Angelina Miltcheva Stoyanova

Turkish Journal of Chemistry

The catalytic effect of chromium(III) and chromium(VI) on the oxidation of sulfanilic acid by hydrogen peroxide was studied. The reaction was followed spectrophotometrically by measuring the absorbance of the reaction product at 360 nm. Under the optimum conditions 2 calibration graphs (for chromium(III) up to 100 ng mL^{-1}, and for chromium(VI) up to 200 ng mL^{-1}) were obtained, using the ``fixed time'' method with detection limits of 4.9 ng mL^{-1} and 3.8 ng mL^{-1}, respectively. The results suggest that at the reaction conditions chromium(VI) is reduced and chromium(III) is oxidized to an intermediate oxidation state and the catalytic action of …

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Proton Conduction In Pvpa --Benzimidazole Hybrid Electrolytes, Fatma Sevi̇l, Ayhan Bozkurt Jan 2005

Proton Conduction In Pvpa --Benzimidazole Hybrid Electrolytes, Fatma Sevi̇l, Ayhan Bozkurt

Turkish Journal of Chemistry

Proton conducting properties of benzimidazole (BnIm) doped poly(vinylphosphonic acid) (PVPA) were studied. The doping ratio, x, which is the number of moles of BnIm per mole of polymer repeat unit, varied from 0.5 to 2. The samples were characterized by FT-IR spectroscopy, thermogravimetric analysis (TG), differential scanning calorimetry (DSC) and impedance spectroscopy. The IR study indicates the protonation of heterocyclic units from the "free nitrogen" side. The proton conductivity and thermal stability of the blends increase with x. Maximum conductivity of PVPA x BnIm blends is approximately 10^{-3} S/cm at 150 °C.

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Synthesis Of Isomorphous Prototypic [Crfe_2o(Aco)_6(Tep)_3]Cl And [Crfe_2o(Aco)_6(Tmp)_3]Cl As Oxo-Centered Hetero Tri-Nuclear Carboxylate Complexes, Massoud Rafizadeh, Reza Tayebee, Vahid Amani Jan 2005

Synthesis Of Isomorphous Prototypic [Crfe_2o(Aco)_6(Tep)_3]Cl And [Crfe_2o(Aco)_6(Tmp)_3]Cl As Oxo-Centered Hetero Tri-Nuclear Carboxylate Complexes, Massoud Rafizadeh, Reza Tayebee, Vahid Amani

Turkish Journal of Chemistry

[CrFe_2O(AcO)_6(TEP)_3]Cl, (1), and [CrFe_2O(AcO)_6(TMP)_3]Cl, (2), were prepared by replacing 3 water molecules in the [CrFe_2O(AcO)_6(H_2O)_3]Cl complex with triethyl- and trimethyl-phosphates, respectively. FT-IR spectroscopy confirmed an oxo-centered, carboxylate-bridged, heteronuclear triangular structure for the title compounds. M_3O and MO_4 units adopted D_{3h} and D_{4h} local symmetry, respectively, and are surrounded by 6 bridging acetates with C_{2v} local symmetry.

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Design And Characterization Of Amino And Chloro Functionalized Rhombohedral Silsesquioxanes, Ahmet Gültek, Turgay Seçki̇n, Hali̇l İbrahi̇m Adigüzel Jan 2005

Design And Characterization Of Amino And Chloro Functionalized Rhombohedral Silsesquioxanes, Ahmet Gültek, Turgay Seçki̇n, Hali̇l İbrahi̇m Adigüzel

Turkish Journal of Chemistry

A more rapid and a versatile synthetic approach for the preparation of polyhedral silsesquioxanes (POSS) by hydrolytic condensation of organosilicon monomers in the presence of a Pt catalyst was studied. The structural properties of POSS molecules were determined by X-ray powder diffraction analysis, yielding a rhombohedral unit cell with a = 11,52796Å and \alpha = 94,9754° for octaaminopropyl-POSS, and a rhombohedral unit cell with a = 11,51421Å, \alpha = 96,7214° for octachloropropyl-POSS. The activation energies were found to be 64.8, and 89.1 kJ/mol for octaaminopropyl-POSS and octachloropropyl-POSS, respectively. The products were also characterized by Fourier transform infrared spectroscopy, ^1H and …

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Synthesis Of Novel Proponohydrazides And Their Hydrolysis Reactions, Mustafa Saçmaci, Emi̇n Saripinar, Yunus Akçamur Jan 2005

Synthesis Of Novel Proponohydrazides And Their Hydrolysis Reactions, Mustafa Saçmaci, Emi̇n Saripinar, Yunus Akçamur

Turkish Journal of Chemistry

4-(4-Methoxybenzoyl)-5-(4-methoxyphenyl)-2,3-furandione 1 reacted with N-aryl substituted phenylhydrazones 3a-h via the p,p'-dimethoxydibenzoylketene intermediate 2 giving the proponohydrazide derivatives 5a-h. In addition, compounds 5a-h were converted into corresponding pyrazolone derivatives 7i,j by the reactions of hydrolysis in acidic solution. The structures of these new synthesized compounds were determined by ^{13}C NMR, ^1H NMR and IR spectroscopic data and elemental analysis.

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Studies On Mononuclear Chelates Derived From Substituted Schiff Base Ligands (Part 4): Synthesis And Characterization Of A New 5-Hydroxysalicyliden-P-Aminoacetophenoneoxime And Its Complexes With Co(Ii), Ni(Ii), Cu(Ii) And Zn(Ii), Erdal Canpolat, Mehmet Kaya Jan 2005

Studies On Mononuclear Chelates Derived From Substituted Schiff Base Ligands (Part 4): Synthesis And Characterization Of A New 5-Hydroxysalicyliden-P-Aminoacetophenoneoxime And Its Complexes With Co(Ii), Ni(Ii), Cu(Ii) And Zn(Ii), Erdal Canpolat, Mehmet Kaya

Turkish Journal of Chemistry

5-Hydroxysalicyliden-p-aminoacetophenoneoxime (LH) was synthesized starting from p-aminoacetophenoneoxime and 5-hydroxysalicylaldehyde. Complexes of this ligand with Co^{+2}, Ni^{+2}, Cu^{+2} and Zn^{+2} salts were prepared. With this ligand, complexes were synthesized using Co^{+2}, Ni^{+2}, Cu^{+2} and Zn^{+2} salt with a metal:ligand ratio of 1:2. Their structures were elucidated on the basis of elemental analyses, IR, ^1H- and ^{13}C-NMR, electronic spectra, magnetic susceptibility measurements, molar conductivity and thermogravimetric analyses.

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Synthesis Of Mannich Bases Of Some 2,5-Disubstituted 4-Thiazolidinones And Evaluation Of Their Antimicrobial Activities, Handan Altintaş, Öznur Ateş, Seher Bi̇rteksöz, Gülten Ötük, Meltem Uzun, Di̇lek Şanata Jan 2005

Synthesis Of Mannich Bases Of Some 2,5-Disubstituted 4-Thiazolidinones And Evaluation Of Their Antimicrobial Activities, Handan Altintaş, Öznur Ateş, Seher Bi̇rteksöz, Gülten Ötük, Meltem Uzun, Di̇lek Şanata

Turkish Journal of Chemistry

4-Carbethoxymethyl-2-[(\alpha -chloropropionyl/\alpha -bromobutyryl/\alpha-chloro-(\alpha-phenyl)acetyl)amino]thiazoles (2a-c) were synthesized by the reaction of 4-carbethoxymethyl-2-aminothiazole (1) with \alpha-chloropropionyl chloride, \alpha-bromobutyryl bromide and \alpha-chloro-\alpha -phenylacetyl chloride, respectively, which were then refluxed with ammonium thiocyanate to obtain 5-substituted 2-[(4-carbethoxymethylthiazol-2-yl)imino]-4-thiazolidinones (3a-c). 3a-c were stirred with formaldehyde and various secondary amines to gain 15 novel compounds with the structure 5-substituted 5-(N,N-disubstituted aminomethyl)-2-[(4-carbethoxymethylthiazol-2-yl)imino]-4- thiazolidinones (4a-o). The antibacterial activities of the compounds against S. aureus ATCC 6538, S. epidermidis ATCC 12228, E. coli ATCC 8739, K. pneumoniae ATCC 4352, P. aeruginosa ATCC 1539, S. typhi, Sh. flexneri and Pr. mirabilis ATCC 14153 were tested using disk diffusion, while the antifungal …

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O-Galloyl Flavonoids From Geranium Pyrenaicum And Their In Vitro Antileishmanial Activity, Di̇lek Erci̇l, Maeki Kaloga, Oliver A. Radtke, M. Koray Sakar, Albrecht F. Kiderlen, Herbert Kolodziej Jan 2005

O-Galloyl Flavonoids From Geranium Pyrenaicum And Their In Vitro Antileishmanial Activity, Di̇lek Erci̇l, Maeki Kaloga, Oliver A. Radtke, M. Koray Sakar, Albrecht F. Kiderlen, Herbert Kolodziej

Turkish Journal of Chemistry

From the aerial parts of Geranium pyrenaicum Burm., a new flavonol glycoside, kaempferol 3-O-(2'',3''-di-O-galloyl)-{\ss}-D-glucopyranoside (7), along with 6 known related glycosides [kaempferol 3-O-\beta-D-glucopyranoside (1), quercetin 3-O-\beta-D-glucopyranoside (2), quercetin 3-O-\beta-D-galactopyranoside (3), kaempferol 3-O-(2''-O-galloyl)-\beta-D-glucopyranoside (4), quercetin 3-O-(2''-O-galloyl)-\beta-D-glucopyranoside (5) and quercetin 3-O-(2'',3''-di-O-galloyl)-{\ss}-D-glucopyranoside (6)] and the ellagitannins corilagin (8) and tellimagrandin I (9) were isolated. Their structures were established from spectroscopic studies (UV, FAB-MS, ^1H and ^{13}C-NMR, ^1H-^1H COSY, HETCOR, HMBC). Compounds 1-7 were evaluated for antileishmanial activity against a panel of Leishmania species (L. major, L. donovani and L. amazonensis), indicating appreciable in vitro activities (IC_{50} 4-27 nM) when compared with Pentostam (IC_{50} …

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Some New Mannich Bases Of 5-Methyl-2-Benzoxazolinones With Analgesis And Anti-Inflammatory Activities, Nesri̇n Gökhan, Meri̇ç Köksal, Esra Küpeli̇, Erdem Yeşi̇lada, Hakki Erdoğan Jan 2005

Some New Mannich Bases Of 5-Methyl-2-Benzoxazolinones With Analgesis And Anti-Inflammatory Activities, Nesri̇n Gökhan, Meri̇ç Köksal, Esra Küpeli̇, Erdem Yeşi̇lada, Hakki Erdoğan

Turkish Journal of Chemistry

The synthesis of a novel series of Mannich bases of 5-methyl-3-substituted piperazinomethyl-2-benzoxazolinones is described. The structures attributed to compounds 3c, 3d and 3f-3n were elucidated using IR and ^1H NMR spectroscopic techniques as well as elemental analysis. The compounds were examined for their in vivo anti-inflammatory and analgesic activities in 2 different bioassays, namely, carrageenan-induced hind paw edema and p-benzoquinone-induced abdominal constriction tests in mice, respectively. In addition, the ulcerogenic effects of the compounds were determined. Among the derivatives tested the most promising results were obtained for the compounds bearing electron-withdrawing substituents (F, Cl, COCH_3) in the para position of …

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