Open Access. Powered by Scholars. Published by Universities.®
- Keyword
-
- 1 (98)
- 2 (83)
- Synthesis (61)
- Adsorption (55)
- Antimicrobial activity (47)
-
- 3 (45)
- Phthalocyanine (35)
- Antibacterial activity (31)
- Molecular docking (30)
- Cytotoxicity (28)
- Preconcentration (26)
- Cyclic voltammetry (25)
- Palladium (25)
- Voltammetry (25)
- Schiff base (24)
- Spectrophotometry (24)
- Copper (23)
- Fluorescence (23)
- Lamiaceae (22)
- DFT (20)
- Kinetics (20)
- Antioxidant activity (19)
- Antioxidant (18)
- Cadmium (18)
- Chitosan (18)
- Nanoparticles (18)
- Photocatalysis (18)
- Antimicrobial (17)
- Catalyst (16)
- Electrospinning (16)
- Publication Year
Articles 1591 - 1620 of 2720
Full-Text Articles in Chemistry
Synthesis And Spectral Characterization Of A Decavanadate/Chitosan Complex, Violeta Dimitrova Kassabova Zhetcheva, Lilyana Parvanova Pavlova
Synthesis And Spectral Characterization Of A Decavanadate/Chitosan Complex, Violeta Dimitrova Kassabova Zhetcheva, Lilyana Parvanova Pavlova
Turkish Journal of Chemistry
A decavanadate/chitosan complex was synthesized by crosslinking chitosan with decavanadate anions at a pH of 3. The materials were characterized by Fourier transformed infrared spectroscopy (FT-IR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), absorption spectroscopy (UV-Vis), and transmission electron microscopy (TEM). The spectroscopic results indicated that the decavanadate/chitosan complex was successfully obtained as result of an ionic crosslinking of the chitosan with decavanadate anions.
Stability Study Of Passive Film On Copper Surface As A Function Of Anodic Potential, Amtul Naseer, Athar Yaseen Khan
Stability Study Of Passive Film On Copper Surface As A Function Of Anodic Potential, Amtul Naseer, Athar Yaseen Khan
Turkish Journal of Chemistry
Results for passive film formation and breakdown on copper disk electrodes in buffer solutions, pH 9.2 and 8.5, were reported earlier. The present studies were carried out in a buffer solution, pH 8.0, and together these studies make good material for understanding the effect of pH changes on film texture as a function of potential. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were used to examine passive film and the variations it went through upon being treated potentiostatically in the range of -0.3 to 0.9 V. On the basis of equivalent circuits used for modeling impedance data in this …
Preparation, Morphology, And Thermomechanical Properties Of Coal Ash/Polyethylene Oxide Composites, Khalid Saeed, Muhmmad Ishaq, Muhmmad Ilyas
Preparation, Morphology, And Thermomechanical Properties Of Coal Ash/Polyethylene Oxide Composites, Khalid Saeed, Muhmmad Ishaq, Muhmmad Ilyas
Turkish Journal of Chemistry
Coal ash/polyethylene oxide (ash/PEO) composite films were prepared by the solution casting technique. Scanning electron microscopy (SEM) micrographs indicated that the ash particles were dispersed and embedded well within the polymer matrix. The size of the ash particles in the PEO matrix was less than 3 \mu m. The polarized optical microscopic (POM) analyses revealed that the pure PEO, upon crystallization, showed distinct crystalline spherulites of a considerable size. The size of the spherulites was decreased by the incorporation of ash particles into the polymer matrix, which might be due to the nucleation role of ash in ash/PEO composite, and …
Assimilable Organic Carbon Generation From Algogenic Organic Matter In Drinking Water, Ji-Hoon Kim, Young-Ju Kim, Tahir Imran Qureshi
Assimilable Organic Carbon Generation From Algogenic Organic Matter In Drinking Water, Ji-Hoon Kim, Young-Ju Kim, Tahir Imran Qureshi
Turkish Journal of Chemistry
A study of assimilable organic carbon (AOC) derived from algogenic organic matter in different drinking water resources was conducted. Seasonal changes in the concentration of AOC at Kamafusa Dam were dependent on the algal cell numbers. Variations in AOC concentrations were found to be more reliant on the AOC-P17 component than the AOC-NOX component. The algal culture experiment showed that extracellular organic matter (EOM) released during the growth of Phormidium tenue in M-11 culture medium led to a significant increase in AOC concentration; however, no significant variations of AOC concentration were observed in CT culture medium containing high amounts of …
Determination Of Stability Constants Of 5-(2-Hydroxybenzylidene)-2-Thioxodihydropyrimidine-4,6(1h,5h)-Dione With Copper(Ii) And Mercury(Ii) Ions, Morteza Bahram, Nader Noroozi Pesyan, Abdolhossein Naseri, Masomeh Tasbihforosh
Determination Of Stability Constants Of 5-(2-Hydroxybenzylidene)-2-Thioxodihydropyrimidine-4,6(1h,5h)-Dione With Copper(Ii) And Mercury(Ii) Ions, Morteza Bahram, Nader Noroozi Pesyan, Abdolhossein Naseri, Masomeh Tasbihforosh
Turkish Journal of Chemistry
In this work, a hard model chemometric method was used to determine the stability constants of copper(II) and mercury(II) complexes with the newly synthesized ligand 5-(2-hydroxybenzylidene)- 2-thioxodihydropyrimidine-4,6(1H,5H)-dione in acetonitrile by UV-Vis spectrophotometry. The ligand forms stable complexes with both metal cations. The protonation constants of the ligand were also measured in an ethanol-water (1:1) mixture.
Synthesis And Properties Of New Optically Active And Organosoluble Poly(Ester-Imide)S Containing L-Valine Moieties In The Main Chain By Direct Polycondensation Reaction, Khalil Faghihi, Meisam Shabanian, Mohsen Hajibeygi
Synthesis And Properties Of New Optically Active And Organosoluble Poly(Ester-Imide)S Containing L-Valine Moieties In The Main Chain By Direct Polycondensation Reaction, Khalil Faghihi, Meisam Shabanian, Mohsen Hajibeygi
Turkish Journal of Chemistry
New optically active poly(ester-imide)s (PEIs) containing bicyclo[2,2,2]oct-7-ene-2,3,5,6-tetracarboxylic diimide in the main chain were prepared by the reaction of N,N'-(bicyclo[2,2,2]oct-7- ene-2,3,5,6-tetra carboxylic)-bis-L-valine 4 as a diacid monomer with various aromatic diols 5a-g in a system of tosyl chloride (TsCl), pyridine (Py), and N,N-dimethylformamide (DMF). The reactions with TsCl were significantly promoted by controlling alcoholysis with diols, in the presence of catalytic amounts of DMF, to give a series of optically active poly(ester-imide)s. The resulting new polymers were obtained in good yields and inherent viscosities, ranging between 0.36 and 0.62 dL g^{-1}, and were characterized with FT-IR and ^1H-NMR spectroscopy, including specific …
Molecular Modeling And Antimycobacterial Studies Of Mannich Bases: 5-Hydroxy-2-Methyl-4h-Pyran-4-Ones, Barkin Berk, Demet Us, Si̇nem Öktem, Zühtü Tanil Kocagöz, Berrak Çağlayan, Işil Aksan Kurnaz, Di̇lek Demi̇r Erol
Molecular Modeling And Antimycobacterial Studies Of Mannich Bases: 5-Hydroxy-2-Methyl-4h-Pyran-4-Ones, Barkin Berk, Demet Us, Si̇nem Öktem, Zühtü Tanil Kocagöz, Berrak Çağlayan, Işil Aksan Kurnaz, Di̇lek Demi̇r Erol
Turkish Journal of Chemistry
The World Health Organization lists tuberculosis among the top 3 leading causes of death from a single infectious agent, and reported cases of multidrug-resistant tuberculosis (MDR-TB) are on the rise. In an attempt to improve MDR-TB drug-directed therapy, we synthesized 11 4-substituted piperazine derivatives of 3-hydroxy-6-methyl-4H-pyran-4-one pharmacophore by reacting 5-hydroxy-2-methyl-4H-pyran-4-one with suitable piperazine derivatives under Mannich reaction conditions. Inhibitory effects of the 11 compounds on Escherichia coli DNA gyrase were evaluated via DNA gyrase supercoiling assay. The minimum inhibitory concentrations (MIC) of the 11 compounds and 41 compounds from our previous studies against Mycobacterium tuberculosis H37RV were assessed, in vitro, …
Synthesis And In Vitro Antimycobacterial Activities Of Novel 6-Substituted-3(2h)-Pyridazinone-2-Acetyl-2-(Substituted/ Nonsubstituted Acetophenone) Hydrazone, Semra Utku, Mehtap Gökçe, Gönül Aslan, Gül Bayram, Mahmut Ülger, Gürol Emekdaş, Mustafa Fethi̇ Şahi̇n
Synthesis And In Vitro Antimycobacterial Activities Of Novel 6-Substituted-3(2h)-Pyridazinone-2-Acetyl-2-(Substituted/ Nonsubstituted Acetophenone) Hydrazone, Semra Utku, Mehtap Gökçe, Gönül Aslan, Gül Bayram, Mahmut Ülger, Gürol Emekdaş, Mustafa Fethi̇ Şahi̇n
Turkish Journal of Chemistry
The difficulty in managing tuberculosis includes the prolonged duration of the treatment, the emergence of drug resistance, and coinfection with HIV/AIDS. Tuberculosis control requires new drugs that act on novel drug targets to help in combating resistant forms of Mycobacterium tuberculosis and reduce the treatment duration. For this purpose, 6-substituted-3(2H)-pyridazinone-2-acetyl-2- (substituted/nonsubstituted acetophenone) hydrazone derivatives were synthesized and their structures were elucidated by elemental analyses, IR, and ^1H-NMR. The in vitro antimycobacterial activities of synthesized compounds 5a-l were determined by the agar proportion method against Mycobacterium tuberculosis H37Rv. Among the target compounds, 5b and 5f exhibited the best antimycobacterial activity, with …
One Pot Synthesis Of Pyridophenanthroline And Pyrrolophenanthroline Derivatives By Regioselective Reaction Between 1,7-Phenanthroline And Dialkyl Acetylenedicarboxylate: New Fused Heterocyclic Compounds, Malek Taher Maghsoodlou, Reza Heydari, Sayyed Mostafa Habibi Khorassani, Batool Tahami Pour, Ghasem Marandi, Farhad Maghfuri
One Pot Synthesis Of Pyridophenanthroline And Pyrrolophenanthroline Derivatives By Regioselective Reaction Between 1,7-Phenanthroline And Dialkyl Acetylenedicarboxylate: New Fused Heterocyclic Compounds, Malek Taher Maghsoodlou, Reza Heydari, Sayyed Mostafa Habibi Khorassani, Batool Tahami Pour, Ghasem Marandi, Farhad Maghfuri
Turkish Journal of Chemistry
1,7-Phenanthroline reacts with dialkyl acetylenedicarboxylate in a regioselective manner to give new macromolecules such as tetramethyl- 6aH-pyrido[1,2-i][1,7]phenanthroline-7,8,9,10-tetracarboxylate and trialkyl pyrrolo[1,2-i][1,7]phenanthroline-7,8,9-tricarboxylate derivatives.
Synthesis And Antimicrobial Activity Of Methoxy Azachalcones And N-Alkyl Substituted Methoxy Azachalconium Bromides, Canan Albay, Nuran Kahri̇man, Nagi̇han Yilmaz İskender, Şengül Alpay Karaoğlu, Nuretti̇n Yayli
Synthesis And Antimicrobial Activity Of Methoxy Azachalcones And N-Alkyl Substituted Methoxy Azachalconium Bromides, Canan Albay, Nuran Kahri̇man, Nagi̇han Yilmaz İskender, Şengül Alpay Karaoğlu, Nuretti̇n Yayli
Turkish Journal of Chemistry
In this study, 18 new N-octyl, N-decyl, and N-dodecyl substituted o-, m-, and p-methoxy (E)-3- and 4-azachalcones, {4- or 3-[(1E)-3-(4-, 3-, or 2-methoxyphenyl)-3-oxoprop-1-en-1-yl]-1-alkyl (C_{8,10,12}) pyridinium bromides} (1a-6a, 1b-1b, and 1c-6c), and 4 new o-, and m-methoxy (E)-3- and 4-azachalcones (2, 3, 5, and 6) were synthesized and tested for antimicrobial activities against Escherichia coli, Yersinia pseudotuberculosis, Enterobacter aerogenes, Pseudomonas aeruginosa, Staphylococcus aureus, Enterococcus faecalis, Bacillus cereus, and Candida albicans. N-Alkyl substituted azachalconium bromides showed good antimicrobial activity against all tested microorganisms with minimal inhibitory concentration (MIC) values in the range of 0.42-58.7 \mu g/mL in most cases. Nonalkylated compounds 1-9 …
A Near-Infrared Fluorescent Sensor For H^+ In Aqueous Solution And Living Cells, Aibin Wu, Liping Duan
A Near-Infrared Fluorescent Sensor For H^+ In Aqueous Solution And Living Cells, Aibin Wu, Liping Duan
Turkish Journal of Chemistry
A heptamethine cyanine-based sensor (1) was designed and synthesized by incorporating heptamethine cyanine fluorophore and methylpiperazine. Sensor 1 exhibited good response to the change of pH levels, and a large Stokes shift (>100 nm) was obtained. Fluorescent image experiments in living cells further demonstrated its potential applications in biological systems.
Chemical Composition And Antimicrobial Activity Of The Essential Oils Of Geranium Columbinum L. And G. Lucidum L. (Geraniaceae), Niko Radulovic, Milan Dekic, Zorica Stojanovic-Radic, Radosav Palic
Chemical Composition And Antimicrobial Activity Of The Essential Oils Of Geranium Columbinum L. And G. Lucidum L. (Geraniaceae), Niko Radulovic, Milan Dekic, Zorica Stojanovic-Radic, Radosav Palic
Turkish Journal of Chemistry
The chemistry of Geranium columbinum and G. lucidum volatiles has been studied here for the first time. The essential oils were obtained by hydrodistillation, analyzed by GC and GC-MS, and screened for their in vitro antibacterial and antifungal activity in a microdilution assay. In total, 172 constituents were identified, accounting for 88.1%-96.7% of the detected GC peak areas. The essential oils consisted mainly of fatty acids and fatty acid-derived compounds (65.0%-86.3%). The major compounds of the essential oils were hexadecanoic acid, hexahydrofarnesyl acetone, and tetracosane. The antimicrobial assay showed a strong activity of the oil from aerial parts of G. …
Electrocatalytic Reactivity Of Pt Ad-Layer Modified Au(111) Single Crystal Electrodes On Reduction Of Oxygen, Zekerya Dursun, Şükri̇ye Ulubay Karabi̇beroğlu, Buket Gelmez, Fatma Ni̇l Ertaş
Electrocatalytic Reactivity Of Pt Ad-Layer Modified Au(111) Single Crystal Electrodes On Reduction Of Oxygen, Zekerya Dursun, Şükri̇ye Ulubay Karabi̇beroğlu, Buket Gelmez, Fatma Ni̇l Ertaş
Turkish Journal of Chemistry
Electrocatalytic reduction of oxygen at electrochemically deposited Pt ad-layer modified Au(111) electrodes was studied in an O_2-saturated NaOH (0.1 M) solution. The results were compared with those obtained by using a polycrystalline Pt electrode and another Pt-deposited electrode prepared by replacement with Cu on bare Au(111). Linear sweep voltammetry displayed a positive shift of the oxygen reduction potential by about 0.14 V compared to the bare Au(111) electrode. This shift was about 0.06 V compared to a Pt disk electrode. Tafel slopes gradually changed between 0.06 and 0.1 V/dec, from 0.075 to -0.10 V/dec, from lower to higher current density …
Enantioselective Henry Reaction Catalyzed By A Novel L-(+)-Aspartic Acid-Derived Schiff Base Ligand And Cu(Ii) Ion, Gamze Koz, Demet Astley, Stephen Thomas Astley
Enantioselective Henry Reaction Catalyzed By A Novel L-(+)-Aspartic Acid-Derived Schiff Base Ligand And Cu(Ii) Ion, Gamze Koz, Demet Astley, Stephen Thomas Astley
Turkish Journal of Chemistry
Mild and efficient enantioselective Henry reactions of nitromethane with various aldehydes were catalyzed by a novel L-(+)-aspartic acid-derived Schiff base ligand in the presence of Cu(II) ions, affording the corresponding adducts in high yields (up to 96%) and enantioselectivities (up to 92% ee).
Simultaneous Determination Of Dopamine, Uric Acid, And Folic Acid By A Modified Tio_2 Nanoparticles Carbon Paste Electrode, Mohammad Mazloum Ardakani, Mohammad Ali Sheikhmohseni, Hadi Beitollahi, Ali Benvidi, Hossein Naeimi
Simultaneous Determination Of Dopamine, Uric Acid, And Folic Acid By A Modified Tio_2 Nanoparticles Carbon Paste Electrode, Mohammad Mazloum Ardakani, Mohammad Ali Sheikhmohseni, Hadi Beitollahi, Ali Benvidi, Hossein Naeimi
Turkish Journal of Chemistry
The electrochemical behavior of dopamine (DA) was studied at the surface of a 2,2-[1,2 buthanediylbis(nit- riloethylidyne)]-bis-hydroquinone/TiO_2 nanoparticles modified carbon paste electrode (BQTMCPE) in aqueous media using voltammetric and chronoamperometric techniques. It was found that under optimum conditions (pH 8.0), the oxidation of DA at the surface of such an electrode occurred at about 220 mV lower than that of an unmodified carbon paste electrode (CPE). Using differential pulse voltammetry (DPV), a highly selective and simultaneous determination of DA, uric acid (UA), and folic acid (FA) was explored at the modified electrode. DPV peak currents of DA, UA, and FA increased …
Synthesis Of Novel Tetraoxime Derivative With Hydrazone Side Groups And Its Metal Complexes, İlknur Babahan, Hüseyi̇n Anil, Nursabah Sarikavakli
Synthesis Of Novel Tetraoxime Derivative With Hydrazone Side Groups And Its Metal Complexes, İlknur Babahan, Hüseyi̇n Anil, Nursabah Sarikavakli
Turkish Journal of Chemistry
In this study, the synthesis of a novel tetraoxime (LH_4) derivative containing hydrazone side groups, and its transition metal complexes with Ni(II), Cu(II), Co(II), and Zn(II) ions, were reported. The ligand was synthesized by reacting anti-glyoximehydrazine (GH_2) with terephthaldialdehyde. Polymeric complexes with Ni(II) and Co(II) and binuclear complexes with Cu(II) and Zn(II) of this tetraoxime were isolated. Structural assignments were supported by a combination of ^1H-NMR, ^{13}C-NMR, HMQC, FT-IR, UV-Vis, thermogravimetric analysis (TGA), molar conductances, elemental analyses, and magnetic susceptibility.
In Situ Catalytic Activities Of 1,3-Dialkyltetrahydropyrimidinium Salts/[Rucl_2(P-Cymene)]_2 System For Transfer Hydrogenation Reactions, Emi̇ne Özge Özcan, Deni̇z Mercan, Nevi̇n Gürbüz, Engi̇n Çeti̇nkaya, Beki̇r Çeti̇nkaya, İsmai̇l Özdemi̇r
In Situ Catalytic Activities Of 1,3-Dialkyltetrahydropyrimidinium Salts/[Rucl_2(P-Cymene)]_2 System For Transfer Hydrogenation Reactions, Emi̇ne Özge Özcan, Deni̇z Mercan, Nevi̇n Gürbüz, Engi̇n Çeti̇nkaya, Beki̇r Çeti̇nkaya, İsmai̇l Özdemi̇r
Turkish Journal of Chemistry
Hydrogen-transfer reduction processes are attracting increasing interest from synthetic chemists in view of their operational simplicity. In the present study novel ruthenium carbene complexes were generated in situ and tested for their transfer hydrogenation reactions. The in situ prepared 3 component 1,3-dialkyltetrahydropyrimidinium salts (LHX)/[RuCl_2(p-cymene)]_2 and KOH catalyzed quantitatively the transfer hydrogenation of ketones under mild reaction conditions in 2-propanol.
Electrocatalytic Oxidation Of Methanol At Pd And Pt Ad-Layer Modified Au(111) Electrodes In Alkaline Solution, Süleyman Koçak, Zekerya Dursun, Fatma Ni̇l Ertaş
Electrocatalytic Oxidation Of Methanol At Pd And Pt Ad-Layer Modified Au(111) Electrodes In Alkaline Solution, Süleyman Koçak, Zekerya Dursun, Fatma Ni̇l Ertaş
Turkish Journal of Chemistry
The electrochemical oxidation of methanol was investigated by using various ad-layer modified Au(111) electrodes in alkaline media in comparison to Au(111), polycrystalline Pd, and polycrystalline Pt electrodes. Catalytic activity of gold toward methanol oxidation has tended to increase in more alkaline media, as reflected in the oxidation peak in the concentration range of NaOH (0.1-3.0 M) studied here. The oxidation peak potential of methanol shifted to more negative potentials, indicating a pH-dependent surface reaction. Among the electrodes studied, single-crystal gold electrode surfaces modified with Pd and Pt ad-layers displayed the highest catalytic activity for methanol oxidation. Additional shifts of about …
Synthesis Of Starch-G-Poly(Acrylic Acid-Co-2-Hydroxy Ethyl Methacrylate) As A Potential Ph-Sensitive Hydrogel-Based Drug Delivery System, Mohammad Sadeghi
Synthesis Of Starch-G-Poly(Acrylic Acid-Co-2-Hydroxy Ethyl Methacrylate) As A Potential Ph-Sensitive Hydrogel-Based Drug Delivery System, Mohammad Sadeghi
Turkish Journal of Chemistry
The present work focused on the design of a drug delivery system (DDS) based on pH-sensitive hydrogel. The hydrogels were prepared via graft copolymerization of mixtures of acrylic acid (AA) and 2-hydroxy ethyl methacrylate (HEMA) onto starch backbones by a free radical polymerization technique. Sodium bicarbonate (NaHCO_3) was added to function as a foaming agent under acidic conditions, rendering the hydrogels to be porous. The porous structure of the hydrogel was essential in this system to yield a large surface area so that 5-fluorouracil (5-FU) release could be facilitated. The hydrogel, thus prepared, possessed a porous structure as determined by …
Electrochemical Impedance Spectroscopy Study On Intercalation And Anomalous Diffusion Of Alcl_4^- Ions Into Graphite In Basic Molten Salt, Ali Ehsani, Mohammad Ghasem Mahjani, Majid Jafarian
Electrochemical Impedance Spectroscopy Study On Intercalation And Anomalous Diffusion Of Alcl_4^- Ions Into Graphite In Basic Molten Salt, Ali Ehsani, Mohammad Ghasem Mahjani, Majid Jafarian
Turkish Journal of Chemistry
Electrochemical impedance spectroscopy (EIS) was employed to investigate diffusion of AlCl_4^- ions in basic (AlCl_3-NaCl-KCl) molten salt. Nyquist plots in different DC offset potentials showed finite and restricted aluminum ion diffusion due to insertion and blocking in the graphite electrode. The general Warburg, open Warburg, and short Warburg impedance in the complex Nyquist plot of this system showed the anomalous diffusion behavior of the ions in the graphite electrode. The diffusion coefficient of the AlCl_4^- ions was calculated from the slope of the Warburg line in a totally blocking film in the graphite electrode and was found to be 2.8 …
Studies On The Mechanism Of Phosphazene Ring-Opening Polymerization (Rop), Selen Bi̇lge
Studies On The Mechanism Of Phosphazene Ring-Opening Polymerization (Rop), Selen Bi̇lge
Turkish Journal of Chemistry
In this study, the ring-opening polymerization (ROP) of cyclic trimer N_3P_3Cl_6 catalyzed by [Et_3Si(N_3 P_3Cl_6)][CHB_{11}H_5Br_6] (3) obtained from the reaction of N_3P_3Cl_6 (1) and Et_3Si(CHB_{11}H_5Br_6) (2) at room temperature was investigated. This provided a unique opportunity to explore the polymerization mechanism. The coordinatively unsaturated cation [N_3P_3Cl_5]^+ is responsible for the ROP of N_3P_3Cl_6, and is formed by the intramolecular elimination of Et_3SiCl from 3. The detection of Et_3SiCl by ^1H-NMR as the catalysis proceeded offers new evidence for the formation of [N_3P_3Cl_5]^+. The progress of the catalysis was followed using ^{31} P-NMR and revealed the build-up of a polymer. Cyclic …
A New And Simple Procedure For The Polarographic Speciation And Determination Of Trace Inorganic As(Iii) And As(V) Species, Ülkü Ünal, Güler Somer
A New And Simple Procedure For The Polarographic Speciation And Determination Of Trace Inorganic As(Iii) And As(V) Species, Ülkü Ünal, Güler Somer
Turkish Journal of Chemistry
A new and simple differential pulse polarographic method was developed for the trace determination of As(III) and As(V) species in the same sample. Among several electrolytes, 0.1 M HCl was found to be the most suitable. As(III) had 3 peaks in this medium, and the peak at --0.82 V was chosen because of its peak shape and response to standard additions. In this medium, the limit of detection for As(III) was found to be 1.5 \times 10^{-7} M. Since As(V) is not electroactive, it had to be reduced first into As(III). For this purpose, KI in an acidic and hot …
A Computational Study On Substituted Diazabenzenes, Selçuk Gümüş
A Computational Study On Substituted Diazabenzenes, Selçuk Gümüş
Turkish Journal of Chemistry
The results of computational calculations on the aromaticity of the monosubstituted diazabenzenes (pyridazine, pyrimidine, and pyrazine) are reported herein. The aromaticity of the parent heterocycle was enhanced by substitution of strong electron-withdrawing groups. The effects of the position of the substituent on the aromaticity and the stability of the system were also investigated by studying all possible derivatives of the systems.
Polyphenolic Compounds From Geranium Purpureum Vill. Growing In Turkey, Di̇dem Şöhretoğlu, Mahmut Koray Sakar, Olov Sterner
Polyphenolic Compounds From Geranium Purpureum Vill. Growing In Turkey, Di̇dem Şöhretoğlu, Mahmut Koray Sakar, Olov Sterner
Turkish Journal of Chemistry
Two new flavonol derivatives, Geranioside A (kaempferol 3-[3-(\alpha-rhamnopyranosyl)-4-oxy-5-hydroxy-6-methyl-3,4-dihyropyran-2H- 2-pyranoside]) (1) and Geranioside B (quercetin 3-[3-(\alpha-rhamnopyranosyl)- 4-oxy-5-hydroxy-6-methyl-3,4-dihyropyran-2H-2-pyranoside]) (2), along with 5 known flavonols (quercetin (3), kaempferol (4), quercetin 4'-O-\beta -glucopyranoside (5), quercetin 3-O-\beta -glucopyranoside (6), and kaemferol-3-O-\beta -glucopyranoside (7)), a gallic acid derivative (methyl gallate (8)), and a hydrolysable tannin (pusilagin (9)), were isolated from the aerial parts of Geranium purpureum. The structures of the isolated compounds were elucidated on the basis of UV, IR, and 1D- and 2D-NMR experiments as well as TOF-MS.
Evaluation Of Solid-Phase Extraction Sorbent With Ketoimine Groups For The Preconcentration Of Benzene And Phenolic Compounds In Water, Iwona Rykowska, Wieslaw Wasiak
Evaluation Of Solid-Phase Extraction Sorbent With Ketoimine Groups For The Preconcentration Of Benzene And Phenolic Compounds In Water, Iwona Rykowska, Wieslaw Wasiak
Turkish Journal of Chemistry
The applicability of silica gel, modified with ketoimine groups, to solid phase extraction (SPE) was tested. Basic characteristics of the modified silica were determined using elemental analysis, and ^{29}Si CP MAS NMR spectroscopy, as well as measurement of specific surface area. Some applications of the sorbent studied to preconcentration and further determination of organic compounds, such as benzene, phenol, and o-chlorophenol, by means of solid-phase extraction (SPE) and gas chromatography are presented. The determined recovery rates were about 95%-98%.
Some Bioactive Organotin(Iv) Derivatives With 3,4-Dichlorophenylacetic Acid: Synthesis, Spectroscopic Properties, And X-Ray Structure Of [Sn_4(C_4h_9)_8(Oocch_2c_6h_3cl_2)_4o_2], Muhammad Adeel Saeed, Muhammad Khawar Rauf, . Imtiaz-Ud-Din, Amin Badshah, Muhammad Zaeem Akhtar, Bushra Mirza
Some Bioactive Organotin(Iv) Derivatives With 3,4-Dichlorophenylacetic Acid: Synthesis, Spectroscopic Properties, And X-Ray Structure Of [Sn_4(C_4h_9)_8(Oocch_2c_6h_3cl_2)_4o_2], Muhammad Adeel Saeed, Muhammad Khawar Rauf, . Imtiaz-Ud-Din, Amin Badshah, Muhammad Zaeem Akhtar, Bushra Mirza
Turkish Journal of Chemistry
Some bioactive organotin(IV) derivatives of 3,4-dichlorophenylacetic acid (HL) were synthesized by reacting the ligand acid with various di- or tri-organotin compounds (in suitable mole ratios) in the presence of triethylamine. The structural investigation was carried out via multinuclear (^1H, ^{13}C, and ^{119}Sn) NMR, IR spectroscopy, and X-ray crystallography. The crystal structure of 4 comprises a central Sn_2O_2 core with O atoms bonded to 2 dibutylbis(3,4-dichlorophenylacetato)tin(IV) units. All the Sn atoms of 4 are essentially 5-coordinated in distorted trigonal-bipyramidal geometry. Some of the compounds exhibited significant antibacterial and antifungal activity.
Density Functional Theory Investigation Of Electrophilic Addition Reaction Of Chlorine To Tricyclo[4.2.2.2^{2,5}]Dodeca-1,5-Diene, Rza Abbasoğlu, Ahmet Yaşar
Density Functional Theory Investigation Of Electrophilic Addition Reaction Of Chlorine To Tricyclo[4.2.2.2^{2,5}]Dodeca-1,5-Diene, Rza Abbasoğlu, Ahmet Yaşar
Turkish Journal of Chemistry
Potential energy surface (PES) of the tricyclo[4.2.2.2^{2,5}]dodeca- 1,5-diene (TCDD)-Cl_2 system was studied by B3LYP/6-311+G(d,p) method and the configurations [reactants, molecular charge-transfer (CT) complex, transition states (TS1 and TS2), intermediate (INT), and product (P)] corresponding to the stationary points (minima or saddle points) were determined. Initially, a molecular CT-complex forms between Cl_2 and TCDD. With a barrier of 22.362 kcal mol^{-1} the CT-complex can be activated to an intermediate (INT) with energy 14.682 kcal mol^{-1} higher than that of the CT-complex. The intermediate (INT) then transforms easily (barrier 5.102 kcal mol^{-1}) into the final, N-type product. Accompanying the breaking of the …
Highly Stereoselective And Efficient Synthesis Of The Dopa Analogue In Pepticinnamin E Via Enantioselective Hydrogenation Of Dehydroamino Acids, Dequn Sun
Turkish Journal of Chemistry
An efficient and new method was developed to prepare the dopa analogue 11 in natural pepticinnamin via catalytic hydrogenation of dehydroamino acids (DDAA) with a good yield and ee. Product 11 is a key intermediate towards the total synthesis of pepticinnamin E and its analogues.
Ionic Liquids As Solvent For Efficient Esterification Of Carboxylic Acids With Alkyl Halides, Yetki̇n Gök, Bülent Alici, Engi̇n Çeti̇nkaya, İsmai̇l Özdemi̇r, Özlem Özeroğlu
Ionic Liquids As Solvent For Efficient Esterification Of Carboxylic Acids With Alkyl Halides, Yetki̇n Gök, Bülent Alici, Engi̇n Çeti̇nkaya, İsmai̇l Özdemi̇r, Özlem Özeroğlu
Turkish Journal of Chemistry
The selective esterification of carboxylic acid derivatives with a variety of alkyl halides was carried out using ionic liquid as solvent in the presence of triethylamine. The reaction was found to proceed under relatively mild conditions with excellent conversions (up to 99%) and selectivities. The ionic liquid was recycled and reused.
Electrooxidation Of Hydrazine By Carminic Acid As A Mediator On A Glassy Carbon Electrode, Mohammad Mazloum Ardakani, Seyed Hossein Moosavizadeh, Ali Sadeghiane, Mohammad Hossein Mashhadzadeh, Mohammad Ali Karimi
Electrooxidation Of Hydrazine By Carminic Acid As A Mediator On A Glassy Carbon Electrode, Mohammad Mazloum Ardakani, Seyed Hossein Moosavizadeh, Ali Sadeghiane, Mohammad Hossein Mashhadzadeh, Mohammad Ali Karimi
Turkish Journal of Chemistry
Electrocatalytic oxidation of hydrazine on a glassy carbon electrode with carminic acid as a homogeneous mediator in 0.1 M phosphate buffer solution (pH 8.0) was studied. Cyclic voltammetry study showed that the catalytic current of the system depends on the concentration of hydrazine. The magnitude of the peak current obtained by linear sweep voltammetry for carminic acid increased sharply in the presence of hydrazine and proportional to the hydrazine concentration in the ranges of 5.0-800.0 \mu M and the detection limit was 3.0 \mu M by this technique. The detection limit was promoted by differential pulse voltammetry and decreased to …