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Articles 1681 - 1710 of 2720
Full-Text Articles in Chemistry
A Novel Glucose Chemiluminescence Biosensor Based On A Rhodanine Derivative Chemiluminescence System And Multilayer-Enzyme Membrane, Jinghua Yu, Lei Ge, Ping Dai, Congcong Zhang, Shenguang Ge, Jiadong Huang
A Novel Glucose Chemiluminescence Biosensor Based On A Rhodanine Derivative Chemiluminescence System And Multilayer-Enzyme Membrane, Jinghua Yu, Lei Ge, Ping Dai, Congcong Zhang, Shenguang Ge, Jiadong Huang
Turkish Journal of Chemistry
Using glucose oxidase as a model enzyme, a novel rhodanine derivative chemiluminescence biosensor for the determination of glucose was formed based on multilayer-enzyme membrane as receptor, which was assembled via layer-by-layer assembly of sol-gel and glucose oxidase-gold nano-particles inside a glass tube. Compared with the traditional chemiluminescence biosensor, the proposed biosensor had some remarkable advantages, such as good selectivity of substrate, good response performance, good stability, good sensitivity, and longer service life. The linear range was from 1.0 \times 10^{-6} to 5.0 \times 10^{-2} mol L^{-1} (r = 0.9991). The detection limit was 5.0 \times 10^{-7} mol L^{-1}. In this …
Synthesis And Spectroscopic Studies Of Some New Organometallic Chelates Derived From Bidentate Ligands, Kiran Singh, Parvesh Puri
Synthesis And Spectroscopic Studies Of Some New Organometallic Chelates Derived From Bidentate Ligands, Kiran Singh, Parvesh Puri
Turkish Journal of Chemistry
A series of organosilicon(IV) and organotin(IV) complexes having the formulae R_2MCl(L^1), R_2MCl(L^2), R_2MCl(L^3), R_2MCl(L^4), R_2M(L^1)_2, R_2M(L^2)_2, R_2M(L^3)_2, and R_2M(L^4)_2, where M = Si and Sn, and R = CH_3, were synthesized with Schiff bases 5-mercapto-4-(pyridine-2-carboxalideneamino)-s-triazole (HL^1), 4-(furfuralideneamino)-5mercapto-s-triazole (HL^2), 4-(2-chlorobenzylideneamino)-5-mercapto-s-triazole (HL^3), and 4-(4-flourobenzylideneamino)-5-mercapto-s-triazole (HL^4). These complexes were characterized by elemental analysis, molar conductance, and spectroscopic studies, including UV, IR, ^1H, ^{13}C, ^{29}Si, and ^{119}Sn NMR spectroscopy. On the basis of these studies, the resulting complexes are proposed to have trigonal bipyramidal and octahedral geometries.
Heterocyclic Synthesis Using Nitrilimines: Part 14. Synthesis Of New Pyrazole Derivatives, Hany Dalloul
Heterocyclic Synthesis Using Nitrilimines: Part 14. Synthesis Of New Pyrazole Derivatives, Hany Dalloul
Turkish Journal of Chemistry
A new series of 1,3,4,5-tetrasubstituted pyrazoles have been synthesized by the 1,3-dipolar cycloaddition of suitable nitrilimines to 3-propylidene and 3-benzylidene-phthalide. Both analytical and spectroscopic data of all the synthesized compounds are in full agreement with the proposed structures.
Surfactant-Controlled Aqueous Synthesis Of Sno_2 Nanoparticles Via The Hydrothermal And Conventional Heating Methods, Muhammad Akhyar Farrukh, Heng Boon Teck, Rohana Adnan
Surfactant-Controlled Aqueous Synthesis Of Sno_2 Nanoparticles Via The Hydrothermal And Conventional Heating Methods, Muhammad Akhyar Farrukh, Heng Boon Teck, Rohana Adnan
Turkish Journal of Chemistry
Tin oxide nanoplates and nanoballs were fabricated using a cationic surfactant of cetyltrimethylammonium bromide (CTABr) as an organic supramolecular template and tin(IV) chloride as an inorganic precursor via the hydrothermal and conventional heating methods. Urea, which decomposes to ammonium and hydroxide ions during hydrolysis, was used as the source of slow homogeneous precipitation of Sn^{4+} with OH^- to control the particle size. The influence of different reaction parameters (time, temperature, and ratio of Sn^{4+} to CTABr) on particle sizes, particle distribution, and morphology was investigated using X-ray diffraction (XRD), transmission electron microscopy (TEM), and Fourier transform infrared (FTIR) spectroscopy. XRD …
Synthesis And Characterization Of Novel Triazol Compounds Containing A Thiophen Ring As Potential Antifungal Agents And The Structure Of 2-(2-Hydroxy-2-P-Tolyethyl)-5-(Thiophen-2-Ylmethyl)- 4-(4h-1,2,4-Triazol-4-Yl)-2h-1,2,4-Triazol-3(4h)-One, Yasemi̇n Ünver, Esra Düğdü, Kemal Sancak, Mustafa Er, Reşat Ustabaş
Synthesis And Characterization Of Novel Triazol Compounds Containing A Thiophen Ring As Potential Antifungal Agents And The Structure Of 2-(2-Hydroxy-2-P-Tolyethyl)-5-(Thiophen-2-Ylmethyl)- 4-(4h-1,2,4-Triazol-4-Yl)-2h-1,2,4-Triazol-3(4h)-One, Yasemi̇n Ünver, Esra Düğdü, Kemal Sancak, Mustafa Er, Reşat Ustabaş
Turkish Journal of Chemistry
A series of new 4-(3,5-disubstitue-4H-1,2,4-triazol-4-yl)- 5-(thiophen-2-yl-methyl)-2H-1,2,4-triazol-3(4H)-ones (3a-c) were obtained by reaction N'-1-ethoxy-2-thiophen-2-yl-ethylydene hydrazino carboxylic acid ethyl ester (1) and 4-amino-4H-1,2,4-triazoles (2). 4-(3,5-disubstitue-4H-1,2,4-triazol-4-yl)-2-(2-oxo-2-arylethyl)-5- (thiophen-2-yl-methyl)-2H-1,2,4-triazol-3(4H)-ones (4a-e) and ethyl 2-(4-(3,5-disubstitue-4H-1,2,4-triazol-4-yl)-5-oxo-3-(thiophen-2-ylmethyl)- 4,5-dihydro-1,2,4-triazol-1-yl)acetates (6a-c) were obtained by reaction of compounds 3 and bromoacetophenon derivatives and bromo ethylacetate, respectively. Compounds 5a-e were synthesized from the reaction of corresponding compounds 4a-e with NaBH_4. Compounds 7a-c were obtained by the reaction compounds 6 and LiAlH_4. Seventeen new compounds were synthesized and characterized by elemental analyses, IR, ^1H-NMR, and ^{13}C-NMR spectral data. The structure of compound 5d was inferred through IR, ^1H-, ^{13}C-NMR, elemental analyses, and X-ray spectral techniques. …
A New Dinuclear Lead(Ii) Complex Of 2,3-Diphenyl-Tetrazole-5-Thione: Synthesis And Characterization, Ruirui Zhuang, Fangfang Jian, Kefei Wang
A New Dinuclear Lead(Ii) Complex Of 2,3-Diphenyl-Tetrazole-5-Thione: Synthesis And Characterization, Ruirui Zhuang, Fangfang Jian, Kefei Wang
Turkish Journal of Chemistry
The present work reports on the synthesis, crystal structure, fluorescence, electrochemical behavior, and thermogravimetric analysis of a new dinuclear lead(II) complex of 2,3-diphenyl-tetrazole-5-thione. Its structure was characterized by X-ray crystallography, IR spectroscopy, and elemental analysis. Each lead atom adopts a distorted octahedral geometry by coordinating to 2 sulfur atoms from 2 2,3-diphenyl-tetrazole-5-thione ligands and 4 oxygen atoms from 3 nitrates. The fluorescence spectrum shows that the title complex has 2 fluorescence emission peaks, at 412 nm and 433 nm. Cyclic voltammetry studies show that the title complex has only one reduction peak, at 0.309 V. The thermogravimetric analysis indicates that …
Preparation Of Polystyrene/Montmorillonite Nanocomposites: Optimization By Response Surface Methodology (Rsm), Sadik Erdem Yalçinkaya, Nuray Yildiz, Mehmet Saçak, Ayla Çalimli
Preparation Of Polystyrene/Montmorillonite Nanocomposites: Optimization By Response Surface Methodology (Rsm), Sadik Erdem Yalçinkaya, Nuray Yildiz, Mehmet Saçak, Ayla Çalimli
Turkish Journal of Chemistry
Preparation of polystyrene (PS)-montmorillonite nanocomposites was carried out in 3 steps: purification and determination of the cation exchange capacity (CEC) of clay, synthesis of organoclay, and preparation of nanocomposites. In organoclay synthesis, 3 types of surfactants, long-chained (cetyltrimethylammonium bromide (CTAB)), short-chained (tetraethylammonium bromide (TEAB)), and ringed (benzyltriethylammonium bromide (BTEAB)), were used. Gallery distances of pure clay and organoclays (CTAB-O, TEAB-O, and BTEAB-O) were determined by X-ray diffraction (XRD) analysis as 1.25, 2.09, 1.52, and 1.63 nm, respectively. Preparation of nanocomposites was carried out by in situ polymerization. Composites, containing 2%, 4%, and 6% organoclay by mass, were characterized by XRD, …
A Simple And Efficient Procedure For Synthesis Of Optically Active 1,3,4-Oxadiazole Derivatives Containing L-Amino Acid Moieties, Naser Foroughifar, Akbar Mobinikhaledi, Sattar Ebrahimi
A Simple And Efficient Procedure For Synthesis Of Optically Active 1,3,4-Oxadiazole Derivatives Containing L-Amino Acid Moieties, Naser Foroughifar, Akbar Mobinikhaledi, Sattar Ebrahimi
Turkish Journal of Chemistry
Some new unsymmetrical and optically active 2,5-disubstituted 1,3,4-oxadiazoles 5a-j were efficiently synthesized by cyclization reaction of diacylhydrazides 4a-j. The synthesis of the title compounds was achieved by the reaction of acyl hydrazides 3a-b and N-phetaloyl-L-amino acids 1a-e in the presence of the phosphoroxy chloride (POCl_3) as an anhydrous reagent.
Friedel-Crafts Acylation Of Arenes With Carboxylic Acids Using Silica Gel Supported Alcl_3, Kaveh Parvanak
Friedel-Crafts Acylation Of Arenes With Carboxylic Acids Using Silica Gel Supported Alcl_3, Kaveh Parvanak
Turkish Journal of Chemistry
Aromatic compounds react smoothly with carboxylic acids in the presence of silica gel supported aluminium trichloride to afford the corresponding ketones with high regioselectivity in high to excellent yields. The catalyst is stable (as a bench top catalyst) and can be easily recovered and reused without appreciable change in its efficiency.
Chemistry Of 2-Aminoanthraquinones, Mostafa Gouda, Moged Berghot, Alaa Shoeip, Khaled Elattar, Abd El Galil Khalil
Chemistry Of 2-Aminoanthraquinones, Mostafa Gouda, Moged Berghot, Alaa Shoeip, Khaled Elattar, Abd El Galil Khalil
Turkish Journal of Chemistry
This review represents a systematic and comprehensive survey of the methods of preparation and the chemical reactivity of 2-aminoanthraquinone. This compound is an important intermediate for the synthesis of a variety of otherwise difficult to obtain synthetically useful and novel heterocyclic systems.
Co(Iii) Catalysed Asymmetric Ring-Opening Of Epichlorohydrin By Salicylaldehyde Derivatives: Reversal Of Enantioselectivity And Rate Acceleration On Addition Of Alcl_3, Leman Karadeni̇z, Gamze Koz, Kadri̇ye Aydin, Stephen Thomas Astley
Co(Iii) Catalysed Asymmetric Ring-Opening Of Epichlorohydrin By Salicylaldehyde Derivatives: Reversal Of Enantioselectivity And Rate Acceleration On Addition Of Alcl_3, Leman Karadeni̇z, Gamze Koz, Kadri̇ye Aydin, Stephen Thomas Astley
Turkish Journal of Chemistry
Using asymmetric Cobalt(III) salen catalysts, the ring-opening of epichlorohydrin by 2,3-dihydroxybenzal- dehyde and 2,4- dihydroxybenzaldehyde was found to occur at the phenolic groups most distant from the aldehydic group. Switching catalysts afforded a reversal in enantioselectivity. For 2,3-dihydroxybenzaldehyde and salicylaldehyde, addition of AlCl_3 to the reaction mixture led to an increase in reaction rate without any decrease in product enantiopurity.
A Novel Optical Membrane With Extended Detection Range Of Ph, Meissam Noroozifar, Mozhgan Khorasani Motlagh, Safeyeh Bahmanzadeh, Shokoofah Boroon
A Novel Optical Membrane With Extended Detection Range Of Ph, Meissam Noroozifar, Mozhgan Khorasani Motlagh, Safeyeh Bahmanzadeh, Shokoofah Boroon
Turkish Journal of Chemistry
A pH optical sensor was developed based on the use of a mixture of Malachite Green Oxalate and Bromocresol Green indicators immobilized in a triacetylcellulose membrane, which had been previously hydrolyzed. Requirements of the pH indicators were investigated, including the effects of the coupling pH, indicator ratio, and concentrations of the indicators. The pH sensor performed with a very fast response (10 s) and long term stability with no significant leaching of the dyes. The sensor had a linear response over a range of 6.6 pH units in the pH range between 0.4 and 7.0. A relative standard deviation of …
Convenient Synthesis And Anion Recognition Property Of Acylhydrazone-Based Molecular Tweezer Receptors, Hai-Xian Ren, Ming-Gen Zhao, Ying-Jin Wang
Convenient Synthesis And Anion Recognition Property Of Acylhydrazone-Based Molecular Tweezer Receptors, Hai-Xian Ren, Ming-Gen Zhao, Ying-Jin Wang
Turkish Journal of Chemistry
Three acylhydrazone-based compounds were designed as novel neutral sensors for anions, and synthesized by simple steps in good yields. Their anion recognition properties were studied by UV-vis and ^1H-NMR spectroscopy. The results showed that the receptors 1, 2, and 3 all had a better selectivity for F^- and CH_3COO^-, but no evident binding with Cl^-, Br^-, I^-, NO_3^-, H_2PO_{4}^-, or HSO_{4}^-. The results indicated that anion recognition was achieved via convergent hydrogen bond interactions from acylhydrazone functionality on the side arms. The UV-vis data indicated that a 1:1 stoichiometry complex was formed between compounds 1, 2, or 3 and anions. …
Bromodimethylsulfonium Bromide/Tetrabutylammonium Nitrite: An Efficient Catalyst Mixture For The Nitration Of Phenols, Batool Akhlaghinia, Ali Reza Pourali
Bromodimethylsulfonium Bromide/Tetrabutylammonium Nitrite: An Efficient Catalyst Mixture For The Nitration Of Phenols, Batool Akhlaghinia, Ali Reza Pourali
Turkish Journal of Chemistry
Nitrophenols were obtained via direct nitration of phenols with tetrabutylammonium nitrite in the presence of bromodimethylsulfonium bromide at room temperature in high yields under aprotic conditions.
Synthesis, Spectroscopic Characterization, Mass Spectrometry, And Crystal Structure Of N-{[(4-Bromophenyl)Amino]Carbonothioyl}Benzamide, Sohail Saeed, Naghmana Rashid, Moazzam Bhatti, Peter Jones
Synthesis, Spectroscopic Characterization, Mass Spectrometry, And Crystal Structure Of N-{[(4-Bromophenyl)Amino]Carbonothioyl}Benzamide, Sohail Saeed, Naghmana Rashid, Moazzam Bhatti, Peter Jones
Turkish Journal of Chemistry
N-{[(4-bromophenyl)amino]carbonothioyl}benzamide was synthesized and characterized by IR, ^1H- and ^{13}C-NMR, mass spectrometry, and elemental analysis. The crystal structure was determined from single crystal X-ray diffraction data. It crystallizes in monoclinic space group P2_1/n with unit cell dimensions a = 13.822(3) Å, b = 5.927(2) Å, c = 16.642(3) Å, and \beta = 103.963(3)°. There is a strong intramolecular hydrogen bond of the type N__H \Lambda O, with an H\Lambda O distance of 2.6129 (11) Å. The mass fragmentation pattern is also discussed.
Synthesis And Crystal Structure Of A Novel Multimodal Ligand, 6,6'-Bis(2-(Di(Pyridin-2-Yl)Methylene)-1-Methylhydrazinyl)-2,2'-Bipyridine, And Its Copper(I) Complex, {[Cu_3l_2](Pf_6)_3° 3h_2o} (1), Çağlar Ağaç, İsmai̇l Yilmaz, Abdurrahman Şengül, Simon J. Coles
Synthesis And Crystal Structure Of A Novel Multimodal Ligand, 6,6'-Bis(2-(Di(Pyridin-2-Yl)Methylene)-1-Methylhydrazinyl)-2,2'-Bipyridine, And Its Copper(I) Complex, {[Cu_3l_2](Pf_6)_3° 3h_2o} (1), Çağlar Ağaç, İsmai̇l Yilmaz, Abdurrahman Şengül, Simon J. Coles
Turkish Journal of Chemistry
The single crystal X-ray structure of the novel multimodal ligand 6,6'-bis(2-(di(pyridin-2-yl)methylene)-1-methylhydrazinyl)-2,2'-bipyridine, C_{34}H_{28}N_{10} (L), was determined at 120 (2) K. The ligand possesses a centre of symmetry that generates a planar bipyridyl core with the hydrazone substituents in a trans-geometry. The di-2-pyridyl moieties at either terminus of the molecule twist out of the plane (52.90 and 56.32 Å). The crystal structure comprises 2-dimensional ribbons that stack about each other so as to optimise van der Waals interactions and packing efficiency. Studies of the coordination properties of the novel multimodal ligand with copper(I) show that 2 ligand strands wrapped around the copper(I) …
Effect Of Various Substituents On Intramolecular 1,1-Vinylboration, Synthesis Of 1-Silacyclobutene Derivatives, Ezzat Khan, Bernd Wrackmeyer
Effect Of Various Substituents On Intramolecular 1,1-Vinylboration, Synthesis Of 1-Silacyclobutene Derivatives, Ezzat Khan, Bernd Wrackmeyer
Turkish Journal of Chemistry
The reaction of 1-boryl-1-alkenyl chlorosilane derivatives with alkynyllithium reagents [Li-C\equiv C-R^3 (R^3~=~Ph, SiMe_3)] at low temperature (--78 °C) affords alkenyl(alkyn-1-yl)silanes. These compounds are precursors of 1-silacyclobutene derivatives, which are formed via intramolecular 1,1-vinylboration. This reaction works for various groups at silicon (R^1/R^2: R^1 = H, Me, Ph; R^2 = Me, Ph) and at the C=C and C\equiv C units (R/R^3: R = ^nBu, Ph; R^3 = ^nBu, Ph, SiMe_3). The conversion into 1-silacyclobutene derivatives is incomplete only in the case of R^3 = SiMe_3. The reactions were monitored by NMR spectroscopy in order to elucidate the reaction mechanism, and the …
Solid Phase Extraction Of Copper, Nickel, And Cobalt In Water Samples After Extraction Using Surfactant Coated Alumina Modified With Indane-1,2,3-Trione 1,2-Dioxime And Determination By Flame Atomic Absorption Spectrometry, Mahdi Hosseini, Nasser Dalali, Ali Karimi, Kourosh Dastanra
Solid Phase Extraction Of Copper, Nickel, And Cobalt In Water Samples After Extraction Using Surfactant Coated Alumina Modified With Indane-1,2,3-Trione 1,2-Dioxime And Determination By Flame Atomic Absorption Spectrometry, Mahdi Hosseini, Nasser Dalali, Ali Karimi, Kourosh Dastanra
Turkish Journal of Chemistry
A simple method for simultaneous pre-concentration of Cu, Ni, and Co metal ions prior to their determination by flame atomic absorption spectrometry is reported. The method is based on the extraction of target ions via complexation with indane-1,2,3-trione 1,2-dioxime immobilized on sodium dodecyl sulfate (SDS) coated alumina. The metal content on the adsorbent was eluted with 4.5 mL of 2 mol L^{-1} nitric acid. The influences of the analytical parameters including pH, sample volume and flow rate, and eluent type and flow rate were investigated. The effect of matrix ions on the retentions of the analytes was also examined. The …
Ethyl 5-Oxo-3-Arylamino-2,5-Dihydroisoxazole-4- Carboxylates As Sources Of Imidazopyrimidine And Aminoindole Derivatives, Ahmad Poursattar Marjani, Jabbar Khalafy
Ethyl 5-Oxo-3-Arylamino-2,5-Dihydroisoxazole-4- Carboxylates As Sources Of Imidazopyrimidine And Aminoindole Derivatives, Ahmad Poursattar Marjani, Jabbar Khalafy
Turkish Journal of Chemistry
The reaction of ethyl 5-oxo-3-arylamino-2,5-dihydroisoxazole-4- carboxylates with 2-chloropyrimidine and 2-chlorobenzoxazole gave the corresponding isoxazolones with pyrimidine and benzoxazole rings substituted on N-2. Their rearrangements with triethylamine in ethanol produced the corresponding imidazopyrimidine and aminoindole derivatives, respectively, through intramolecular cyclisation.
Reactions Of 4-Benzoyl-1,5-Diphenyl-1h-Pyrazole-3- Carboxylic Acid Chloride With Various Hydroxylamines And Carbazates, Eli̇f Korkusuz, İsmai̇l Yildirim
Reactions Of 4-Benzoyl-1,5-Diphenyl-1h-Pyrazole-3- Carboxylic Acid Chloride With Various Hydroxylamines And Carbazates, Eli̇f Korkusuz, İsmai̇l Yildirim
Turkish Journal of Chemistry
The 1H-pyrazole-3-carboxylic acid 2 was converted via reactions of its acid chloride 3 with various hydroxylamine 4a-f and carbazate derivatives 8a-c into the corresponding novel N-substituted-4-benzoyl-1,5-dipenyl-1H-pyrazole-3-carboxamides 5a-c, N,N-disubstituted-4-benzoyl-1,5-diphenyl-1H-pyrazole-3-carboxylates 6d,e, 4-benzoyl-N-{[(4-benzoyl-1,5-diphenyl-1H-pyrazol-3-yl)carbonyl]oxy}- N-methyl-1,5dip- henyl-1H-pyrazole-3-carboxamide (7), and 4-benzoyl-N'-(alkoxycarbonyl)-1,5-diphenyl-1H-pyrazole-3-car- bohydrazides 9a,b and 10, respectively, in good yields (65\%-90\%). The reactions of 3 with 4 and 8 in xylene for 8-15 h with catalytic amounts of base led to the formation of the products 5-7, 9, and 10. The structures of all new synthesized compounds were established by the ^{13}C-NMR, ^1H-NMR, IR spectroscopic data, and elemental analyses.
Vapor Phase Alkylation Of Toluene Using Various Alcohols Over H3po4/Mcm-41 Catalyst: Influence Of Reaction Parameters On Vapor Phase Alkylation Of Toluene Using Various Alcohols Over H_3po_4/Mcm-41 Catalyst: Influence Of Reaction Parameters On Selectivity And Conversion, Alireza Abbaspourrad, Roozbeh Javadkalbasi, Farzad Zamani
Vapor Phase Alkylation Of Toluene Using Various Alcohols Over H3po4/Mcm-41 Catalyst: Influence Of Reaction Parameters On Vapor Phase Alkylation Of Toluene Using Various Alcohols Over H_3po_4/Mcm-41 Catalyst: Influence Of Reaction Parameters On Selectivity And Conversion, Alireza Abbaspourrad, Roozbeh Javadkalbasi, Farzad Zamani
Turkish Journal of Chemistry
A mesoporous MCM-41 molecular sieve material with a molar ratio of SiO_2/Al_2O_3 = 70 and loaded with H_3PO_4 was used as a catalyst for the alkylation of toluene, using various alcohols, namely methanol, iso-propanol, and tert-butanol, as alkylating agents. Para-alkylated toluene was the predominant product, formation of which was enhanced by moderate temperature, low amounts of the alkylating agents in the feed, and high carrier gas flow rate. Time on stream was found to exert a profound effect on the selectivity and conversion to the different products.
Determination Of Trace Element Contents Of Thymus Species From Turkey, Fatümetüzzehra Küçükbay, Ebru Kuyumcu
Determination Of Trace Element Contents Of Thymus Species From Turkey, Fatümetüzzehra Küçükbay, Ebru Kuyumcu
Turkish Journal of Chemistry
Eleven mineral and trace elements (Mg, Ca, K, Fe, Mn, Al, Zn, Cu, Cd, Ni, and Pb) were determined in the Thymus species growing in Turkey. The total concentrations were measured in samples mineralized with concentrated nitric acid and hydrogen peroxide in a microwave system. The determination of mineral and trace elements in the leaves of the Thymus species was carried out by flame and graphite furnace atomic absorption spectrometry. The accuracy of the method was ensured by using standard reference material (NIST-SRM 1515 apple leaves). The concentration of elements in the Thymus species and their biological activity on humans …
Biotransformation Of Danazol By Fusarium Solani And Gibberella Fujikuorii, And Prolyl Endopeptidase Inhibition Studies Of Transformed Products, Azizuddin Shaikh, Muhammad Iqbal Choudhary
Biotransformation Of Danazol By Fusarium Solani And Gibberella Fujikuorii, And Prolyl Endopeptidase Inhibition Studies Of Transformed Products, Azizuddin Shaikh, Muhammad Iqbal Choudhary
Turkish Journal of Chemistry
Biotransformation of danazol (17\beta-hydroxy-17\alpha-pregna-2,4-dien-20-yno-[2,3-d] isoxazole) (1) on fermentation with Fusarium solani yielded 17\beta-hydroxy-2-(hydroxymethyl)-17\alpha -pregn-4-en-20-yn-3-one (2) and 17\beta -hydroxy-2-(hydroxymethyl)-17\alpha-pregna-1,4-dien-20-yn-3-one (3), while the fermentation of 1 with Gibberella fujikuorii yielded compound 2 only. The structures of these compounds were deduced on the basis of modern spectroscopic techniques. Prolyl endopeptidase inhibition activities of danazol (1) and its transformed products 2 and 3 are also studied.
Computational Study On Nitronium Squarate - Potential Oxidizers For Solid Rocket Propulsion?, Eli̇f Gökçinar, Thomas Klapötke
Computational Study On Nitronium Squarate - Potential Oxidizers For Solid Rocket Propulsion?, Eli̇f Gökçinar, Thomas Klapötke
Turkish Journal of Chemistry
The enthalpies of formation for solid ionic nitronium squarate, [NO_2]_2[C_4O_4], and covalent squaric acid dinitrate ester, O_2N-C_4O_4-NO_2, were calculated using the complete basis set (CBS-4M) method of Petersson and coworkers in order to obtain very accurate energies. The covalent form (O_2N-C_4O_4-NO_2) was identified as the more stable isomer. The combustion parameters with respect to possible use as ingredients in solid rocket motors for both stable species were calculated using the EXPLO5 code. The performance of an aluminized formulation with covalently bound dinitrate ester (O_2N-C_4O_4-NO_2) was shown to be comparable to that of ammonium perchlorate/aluminum. This makes squaric acid dinitrate ester …
Comparative Essential Oil Analysis Of Geranium Sylvaticum Extracted By Hydrodistillation And Microwave Distillation, Nuran Kahri̇man, Gonca Tosun, Hasan Genç, Nuretti̇n Yayli
Comparative Essential Oil Analysis Of Geranium Sylvaticum Extracted By Hydrodistillation And Microwave Distillation, Nuran Kahri̇man, Gonca Tosun, Hasan Genç, Nuretti̇n Yayli
Turkish Journal of Chemistry
The essential oil of Geranium sylvaticum L. (Geraniaceae) was isolated by hydrodistillation (HD) and microwave distillation (MD). The composition of the volatile oils was characterized by GC-FID and GC-MS. A total of 73 and 70 compounds were identified, constituting over 90.3% and 98.7% of oil composition of G. sylvaticum, respectively. Sesquiterpene hydrocarbons were shown to be the main group of constituents (HD: 31.7% and MD: 39.8%). The major component of the oils of G. sylvaticum was \gamma -muurolene (HD: 10.9% and MD: 19.6%). The comparative study showed that the amount of total volatiles (98.7%) and the major constituent (39.8%) were …
Quantum Chemical Studies On Tautomerism And Basicity Behavior Of Some 1,2,4-Triazole Derivatives, Cemi̇l Öğreti̇r, Yadi̇gar Gülseven Sidir, İsa Sidir, Erol Taşal
Quantum Chemical Studies On Tautomerism And Basicity Behavior Of Some 1,2,4-Triazole Derivatives, Cemi̇l Öğreti̇r, Yadi̇gar Gülseven Sidir, İsa Sidir, Erol Taşal
Turkish Journal of Chemistry
The acidity constants, relative stabilities, and tautomeric equilibrium constants of some 1,2,4-triazole derivatives were determined using the density functional theory (DFT) with the B3LYP method and 6-311G(d,p) basis set. The integral equation formalism version of the polarizable continuum model (IEFPCM) was used in the calculations of the aqueous phase. The calculated tautomeric equilibrium and relative stabilities values revealed that the 4H-1,2,4 triazole form for all studied molecules was favored over the 1H-1,2,4 triazole form. Protonation processes indicated the predominance of the 1H-1,2,4 triazole form over the 2H-1,2,4 triazole form. The correlation attempt between the experimental and the calculated acidity constants, …
Silver Ion-Assisted Ring Expansions In Different Solvent Systems, Mesut Boz, Hafi̇ze Çalişkan, Ömer Zai̇m
Silver Ion-Assisted Ring Expansions In Different Solvent Systems, Mesut Boz, Hafi̇ze Çalişkan, Ömer Zai̇m
Turkish Journal of Chemistry
Several ring expansion products carrying vinylic bromo functionality were synthesized by opening of the geminal dibromobicyclo[n.1.0]alkanes ring. Dibromocarbene was formed from bromoform and potassium tert-butoxide in hexane. Its reaction with various cyclic alkenes was the resultant dibromobicyclo[n.1.0]alkanes. Then, opening was performed using AgNO_3 in various solvent systems, such as acetic acid/DMSO, acetic acid/DMF, CH_3OH/acetone, and H_2O/DMF.
Water-Gas Shift Reaction Over Bimetallic Pt-Ni/Al_2o_3 Catalysts, Burcu Selen Çağlayan, Ahmet Erhan Aksoylu
Water-Gas Shift Reaction Over Bimetallic Pt-Ni/Al_2o_3 Catalysts, Burcu Selen Çağlayan, Ahmet Erhan Aksoylu
Turkish Journal of Chemistry
The water-gas shift (WGS) activity of bimetallic Pt-Ni/Al_2O_3 catalysts was investigated in the temperature range 200-450 °C using an idealized feed composition consisting of 3% CO and 6%-10% H_2O. The effects of the Ni content, space velocity, and H_2O/CO ratio on the catalytic performance of the catalysts were studied. An increase in the Ni content and H_2O/CO ratio shifted the carbon monoxide conversion--temperature curve toward lower reaction temperatures. No detectable methane formation was observed in the catalytic reaction tests. The results indicate that Pt-Ni/Al_2O_3 catalysts are highly selective and active for water-gas shift reactions under idealized conditions.
Methanol Dehydration Reaction To Produce Clean Diesel Alternative Dimethylether Over Mesoporous Aluminosilicate-Based Catalysts, Di̇lek Varişli, Kenan Cem Tokay, Ayşegül Çi̇ftçi̇, Ti̇mur Doğu, Gülsen Doğu
Methanol Dehydration Reaction To Produce Clean Diesel Alternative Dimethylether Over Mesoporous Aluminosilicate-Based Catalysts, Di̇lek Varişli, Kenan Cem Tokay, Ayşegül Çi̇ftçi̇, Ti̇mur Doğu, Gülsen Doğu
Turkish Journal of Chemistry
Due to its good burning characteristics and high cetane number, dimethylether (DME) is considered as a highly attractive and clean alternative to diesel fuel. This ether can be produced by methanol dehydration reaction over solid acid catalysts. In the present study, activities of mesoporous aluminosilicate catalysts prepared by the hydrothermal synthesis route and containing Al/Si atomic ratios ranging between 0.03 and 0.18 were tested in methanol dehydration. The optimum Al/Si ratio was 0.09 for DME synthesis. Activity of silicotungstic acid (STA) impregnated aluminosilicate was also tested. This STA impregnated catalyst showed very high DME yield values at temperatures as low …
Synthesis, Characterization, And Optical Properties Of Novel 2,5-Bis[4-(2-(-Arylvinyl)Phenyl]-1,3,4-Oxadiazoles, Dao-Hang He, Yong-Chuang Zhu, Zhuo-Ru Yang, Ai-Xi Hu, Gao Cao
Synthesis, Characterization, And Optical Properties Of Novel 2,5-Bis[4-(2-(-Arylvinyl)Phenyl]-1,3,4-Oxadiazoles, Dao-Hang He, Yong-Chuang Zhu, Zhuo-Ru Yang, Ai-Xi Hu, Gao Cao
Turkish Journal of Chemistry
Six novel 2,5-bis[4-(2-arylvinyl)phenyl]-1,3,4-oxadiazoles were synthesized by introducing 1,3,4-oxadiazole moiety into the stilbene skeleton. The synthesis route included the cyclization of p-toluic acid and hydrazine hydrate catalyzed by polyphosphoric acid (PPA), bromination of 1,3-dibromo-5,5-dimethylhydantoin (DBDMH), esterification, and the Wittig-Horner reaction. All the title compounds were characterized by ^1H-NMR, MS, and elemental analysis. UV-Vis absorption and fluorescence emission spectra in THF solution were investigated; the compounds may have potential for use in organic optical materials.