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Full-Text Articles in Physical Sciences and Mathematics

Highly Stereoselective And Efficient Synthesis Of The Dopa Analogue In Pepticinnamin E Via Enantioselective Hydrogenation Of Dehydroamino Acids, Dequn Sun Jan 2010

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.


Synthesis Of Some New Biheterocyclic Triazole Derivatives And Evaluation Of Their Antimicrobial Activity, Hakan Bektaş, Ahmet Demi̇rbaş, Nesli̇han Demi̇rbaş, Şengül Alpay Karaoğlu Jan 2010

Synthesis Of Some New Biheterocyclic Triazole Derivatives And Evaluation Of Their Antimicrobial Activity, Hakan Bektaş, Ahmet Demi̇rbaş, Nesli̇han Demi̇rbaş, Şengül Alpay Karaoğlu

Turkish Journal of Chemistry

2-{3-(4-Substitutedbenzyl)-4-[2-(1H-indol-3-yl)ethyl]-5-oxo-4,5- dihydro-1H-1,2,4-triazol-1-yl}-N'-(aryl-methylene)acetohydrazides (5a-g), 4-amino-2-{-(4-substitutedbenzyl)-5-oxo-4,5-dihydro-1H-1,2,4-triazol- 1-yl}-N'-(arylmethylene)acetohydrazides (6a,b), and 4-[2-(1H-indol- 3-yl)ethyl]-5-(4-substitutedbenzyl)-2-{5-(phenylamino)-1,3,4-thiadiazol- 2-yl]methyl}-2,4-dihydro-3H-1,2,4-triazol-3-ones (8a,b) were synthesized starting from 4-alkyl-5-(4-substitutedbenzyl)-2,4-dihydro- 3H-1,2,4-triazol-3-ones (2a-c) by several steps and their structures were well characterized by elemental analyses, IR, ^1H-NMR, ^{13}C-NMR, and mass spectral studies. They were also screened for their microbial activities. The obtained antimicrobial activity results revealed that 12 among the 24 compounds tested displayed variable growth inhibition effects on the tested gram-positive and gram-negative bacterial strains. None of the compounds showed antifungal activity against yeast-like fungi.


Performance Evaluation Of Platinum-Based Catalysts For The Development Of Proton Exchange Membrane Fuel Cells, Abdul Sattar Ali Khan, Riaz Ahmed, Muhammad Latif Mirza Jan 2010

Performance Evaluation Of Platinum-Based Catalysts For The Development Of Proton Exchange Membrane Fuel Cells, Abdul Sattar Ali Khan, Riaz Ahmed, Muhammad Latif Mirza

Turkish Journal of Chemistry

Platinum-based catalysts are considered the most efficient catalysts for triggering electrochemical reactions in proton exchange membrane (PEM) fuel cells. In the present study, commercial catalysts containing 10% and 30% Pt supported on Vulcan XC-72 carbon were studied to assess their performance in PEM fuel cells. Both catalysts consisted of Pt particles of almost the same size. The utility of these catalysts in PEM fuel cells was studied by finding the real surface area and rate of electro-oxidation of methanol in 0.5 M H_2SO_4 by using cyclic voltammetry. The methanol oxidation reaction was used for characterization of catalysts of PEM fuel …


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 Jan 2010

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 …


Synthesis And Antimicrobial Activity Of N-Alkyl Substituted P-Methyl (E)-3- And 4-Azachalconium Bromides, Nuretti̇n Yayli, Gülbi̇n Misir, Nuran Yayli, Ahmet Yaşar, Emi̇ne Demi̇r, Zi̇hni̇ Demi̇rbağ Jan 2010

Synthesis And Antimicrobial Activity Of N-Alkyl Substituted P-Methyl (E)-3- And 4-Azachalconium Bromides, Nuretti̇n Yayli, Gülbi̇n Misir, Nuran Yayli, Ahmet Yaşar, Emi̇ne Demi̇r, Zi̇hni̇ Demi̇rbağ

Turkish Journal of Chemistry

Twenty new N-alkyl substituted p-methyl (E)-3- and 4-azachalcones (1a-j, 2a-j){3-[(1E)-3-(4-methylp-henyl)-3- oxoprop-1-en-1-yl]-1-alkyl (C_{5-12,_{14-15) pyridinium bromides (1a-j) and 4-[(1E)-3-(4-methylp-henyl)-3-oxoprop-1-en-1-yl]-1-alkyl (C_{5-12,_{14-15) pyridinium bromides (2a-j)} were synthesized and tested for antimicrobial activities against Staphylococcus aureus, Staphylococcus epidermidis, Bacillus subtilis, Enterococcus faecalis, Proteus vulgaris, and Escherichia coli. They showed good antimicrobial activity especially against the gram-positive bacteria tested with minimal inhibitory concentration (MIC) values less than 4.7 \mu g/mL in most cases. The optimum length of the alkyl chain for better and broader activity is situated in the range of 8-12 carbon atoms in the series of compounds 1a-j, 2a-j. The non-alkylated compounds 1-2 were …


Synthesis, Structural Determination, And Biological Activity Of New 7-Hydroxy-3-Pyrazolyl-4h-Chromen- 4-Ones And Their O-\Beta-D-Glucosides, Kishor Hatzade, Vijay Taile, Pravin Gaidhane, Vishwas Ingle Jan 2010

Synthesis, Structural Determination, And Biological Activity Of New 7-Hydroxy-3-Pyrazolyl-4h-Chromen- 4-Ones And Their O-\Beta-D-Glucosides, Kishor Hatzade, Vijay Taile, Pravin Gaidhane, Vishwas Ingle

Turkish Journal of Chemistry

A convenient route to synthesize some new medicinally important 7-hydroxy-3-pyrazolyl chromones (3a-i) is described. The interaction of 7-hydroxy-3-formyl chromone (1) with various substituted acetophenones and further cyclization with hydrazine hydrate in an aprotic solvent followed by condensation with 2, 3, 4, 6-tetra-o-acetyl-\alpha-dglucopyranosyl bromide afforded 2, 3, 4, 6-tetra-o-acetyl-\beta-d-glucopyranosyloxy-3-(3-aryl-1H-pyrazol-5- yl)-4H-chromen-4-ones (4a-i). Later deacetylation with anhydrous zinc acetate in methanol gave 7-o-\beta-d-glucopyranosyloxy-3-(3-aryl- 1H-pyrazol-5-yl)-4H-chromen-4-ones (5a-i). These compounds were evaluated for their in vitro antimicrobial and anti-oxidant activity. The structures of these newly synthesized o-glucosides were established by IR, NMR, mass spectra, elemental analysis, and chemical analysis.


Synthesis And Characterization Of Non-Symmetric Tetradentate Complexes Of Zn(Ii), Co(Ii), And Cu(Ii), Maryam Lashanizadegan, Shima Seraj Jan 2010

Synthesis And Characterization Of Non-Symmetric Tetradentate Complexes Of Zn(Ii), Co(Ii), And Cu(Ii), Maryam Lashanizadegan, Shima Seraj

Turkish Journal of Chemistry

The non-symmetrical tetradentate Schiff-base H_2L was obtained using the half-unit N-(1-hydroxy-2-acetophenone)-1-amino- 2-phenyleneimine (HL) with 2-hydroxyl-1-naphthaldehyde. ZnL, CoL, and CuL complexes were prepared and characterized by ^1H-NMR, IR, electronic, and atomic absorption spectra. The single crystal X-ray structure of CuL was determined. Crystal data for CuL are triclinic space group P-1, a = 8.3933 (17) Å, b = 11.197 (2) Å, c = 13.381 (3) Å, \alpha = 95.29 (3)°, \beta = 94.37 (3)°, \gamma = 95.82 (3)°, and z = 2.


Inclusion And Release Of Theophylline From Chitosan Based Microparticles, Niculina Popa, Ovidiu Novac, Lenuta Profire, Doina Hritcu, Marcel Ionel Popa Jan 2010

Inclusion And Release Of Theophylline From Chitosan Based Microparticles, Niculina Popa, Ovidiu Novac, Lenuta Profire, Doina Hritcu, Marcel Ionel Popa

Turkish Journal of Chemistry

Chitosan (CS) based microparticles for controlled release of theophylline (THP) were obtained by ionic gelation. The microparticles were characterized by laser diffraction analysis (particle size), scanning electron microscopy (SEM), FTIR spectroscopy, and thermogravimetric analysis. The average diameter of the CS-THP microparticles was 182 \mu m. The FTIR spectra confirmed that new hydrogen bonds had formed between the carbonylic group belonging to THP and the amino group of CS, while the thermogravimetric analysis showed a modified stability in the obtained particles and confirmed the presence of an interaction between the drug and CS. The THP release process was monitored for up …


Stabilizing Cyclacene Molecules, Muthana Shanshal Jan 2010

Stabilizing Cyclacene Molecules, Muthana Shanshal

Turkish Journal of Chemistry

It is shown that introducing a single methylene group into each trannulene ring of a cyclacene molecule compels the formation of a non-bonded molecular orbital, NBMO, in the ring. The union of both trannulenes conforms to a first order perturbation change in the total energy according to Dewar's PMO theory. The NBMO coefficients can be calculated then according to Coulson's pairing theorem. The PMO calculated new HOMO-LUMO energies of the cyclacene indicate the relative stabilization of the singlet over the triplet state of the cyclacene. The results are confirmed by the DFT calculation of differently substituted bis, methylene cyclacenes. The …


Direct Reductive Amination Of Carbonyl Compounds Using Sodium Borohydride-Silica Chloride, Heshmatollah Alinezhad, Mahmood Tajbakhsh, Neda Hamidi Jan 2010

Direct Reductive Amination Of Carbonyl Compounds Using Sodium Borohydride-Silica Chloride, Heshmatollah Alinezhad, Mahmood Tajbakhsh, Neda Hamidi

Turkish Journal of Chemistry

A simple and convenient procedure for reductive amination of aldehydes and ketones using sodium borohydride in the presence of silica chloride as an active, inexpensive, recoverable, and recyclable catalyst is described. The reactions were carried out with equimolar amounts of amine and carbonyl compound using silica chloride-sodium borohydride in THF at room temperature.


Composition Of The Essential Oils Of Pinus Nigra Arnold From Turkey, Ekrem Sezi̇k, Osman Üstün, Bülent Demi̇rci̇, Kemal Hüsnü Can Başer Jan 2010

Composition Of The Essential Oils Of Pinus Nigra Arnold From Turkey, Ekrem Sezi̇k, Osman Üstün, Bülent Demi̇rci̇, Kemal Hüsnü Can Başer

Turkish Journal of Chemistry

Essential oil composition of the needles of Pinus nigra Arnold collected from different localities in Turkey was investigated by GC and GC/MS. The main components in the oils were \alpha-pinene, \beta-pinene, \beta-caryophyllene, and germacrene D.


An Investigation Of Energy Transfer Between Coumarin 35 And Xanthene Derivatives In Liquid Medium, Mahmut Toprak, Mustafa Arik Jan 2010

An Investigation Of Energy Transfer Between Coumarin 35 And Xanthene Derivatives In Liquid Medium, Mahmut Toprak, Mustafa Arik

Turkish Journal of Chemistry

The energy transfer between coumarin 35 (C35) and pyronin compounds, which are xanthene derivatives, i.e. pyronin B (PyB) and pyronin Y (PyY), in methanol was investigated at room temperature by using steady-state absorption, emission, and time-resolved fluorescence spectroscopy. Fluorescence energy transfer rate constants (k_T) and critical radius (R_0) were determined for C35-PyB and C35-PyY molecular pairs in methanol. The obtained values of k_T and R_0 indicated that the dipole-dipole interaction between C35-PyB and C35-PyY molecular pairs accounted for the energy transfer mechanism. The energy transfer efficiency and the distance between the donor and acceptor (r) were also calculated for donor-acceptor …


Picolyl Substituted N-Heterocyclic Carbene/Palladium Catalyzed Heck Reactions, Murat Yi̇ği̇t, Beyhan Yi̇ği̇t, İsmai̇l Özdemi̇r, Engi̇n Çeti̇nkaya Jan 2010

Picolyl Substituted N-Heterocyclic Carbene/Palladium Catalyzed Heck Reactions, Murat Yi̇ği̇t, Beyhan Yi̇ği̇t, İsmai̇l Özdemi̇r, Engi̇n Çeti̇nkaya

Turkish Journal of Chemistry

Novel 1,3-dialkylimidazolinium and 1,3- dialkyltetrahydropyrimidinium hexafluorophosphate salts as N-heterocyclic carbene precursors were prepared by reacting N,N'-dialkylethandiamine or N,N'-dialkylpropandiamine, triethyl orthoformate, and ammonium hexafluorophosphate. The salts were characterized spectroscopically and tested in homogeneous Heck reactions.


Synthesis And Antimicrobial Activities Of 2-(5-Mercapto)-1,3-Oxadiazol-2-Ylmethyl-1,2,4-Triazol-3-One Derivatives, Nesli̇han Demi̇rbaş, Ahmet Demi̇rbaş, Hakan Bektaş, Şengül Alpay Karaoğlu, Deni̇z Şahi̇n Jan 2010

Synthesis And Antimicrobial Activities Of 2-(5-Mercapto)-1,3-Oxadiazol-2-Ylmethyl-1,2,4-Triazol-3-One Derivatives, Nesli̇han Demi̇rbaş, Ahmet Demi̇rbaş, Hakan Bektaş, Şengül Alpay Karaoğlu, Deni̇z Şahi̇n

Turkish Journal of Chemistry

The synthesis of 4-amino-2-[(5-mercapto-1,3,4-oxadiazol-2- yl)methyl]-5-(4-methylphenyl)-2,4-dihydro-3H-1,2,4-triazol-3-one (2) and 4-amino-2-[(4-amino-5-mercapto-4H-1,2,4-triazol-3-yl)methyl]- 5-(4-methylphenyl)-2,4-dihydro-3H-1,2,4-triazol-3-one (5) was performed starting from 2-[4-amino-3-(4-methylphenyl)-5-oxo-4,5- dihydro-1H-1,2,4-triazol-1-yl]acetohydrazide (1). The treatment of 2 and 5 with 4-fluorobenzaldehyde (for 8) or salicylaldehyde (for 6) afforded the corresponding Schiff bases (6 and 8). The condensation of 5 with phenacyl bromide produced 4-amino-5-(4-methylphenyl)-2- [(6-phenyl-7H-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazin-3-yl)methyl]- 2,4-dihydro-3H-1,2,4-triazol-3-one (7). The alkylation of 2 and 8 was carried out by using methyl iodide in basic media. Compounds 3 and 10a,b were prepared by aminoalkylation of 2 and 8 with 4-fluorophenyl piperazine, morpholine, or 4-methyl piperazine in the presence of formaldehyde. The synthesized compounds were screened for their antimicrobial activities …


Convenient Synthesis Of Monomeric Steroids From Steroidal Oxalate Dimers Using Flash Vacuum Pyrolysis (Fvp), Lutfun Nahar, Alan Turner, Satyajit Sarker Jan 2010

Convenient Synthesis Of Monomeric Steroids From Steroidal Oxalate Dimers Using Flash Vacuum Pyrolysis (Fvp), Lutfun Nahar, Alan Turner, Satyajit Sarker

Turkish Journal of Chemistry

Flash vacuum pyrolysis (FVP) or thermolysis (FVT), an environmentally friendly method for studying organic reaction mechanisms as well as synthesis, was applied to a series of oxalate dimers (1, 3, 5, 7, 9, 11, 13, and 15) to synthesise monomeric enes, dienes, and a triene (2, 4, 6, 8, 10, 12, 14, and 16). All steroidal monomers were identified by spectroscopic means.


Comparative Kinetic Studies On The Alkaline Hydrolysis Of Halogen Substituted Isocoumarins, Hafiz Badaruddin Ahmad, Muhammad Aslam Malana, Muhammad Yousaf, Muhammad Rehan, Mazhar Abbas Jan 2010

Comparative Kinetic Studies On The Alkaline Hydrolysis Of Halogen Substituted Isocoumarins, Hafiz Badaruddin Ahmad, Muhammad Aslam Malana, Muhammad Yousaf, Muhammad Rehan, Mazhar Abbas

Turkish Journal of Chemistry

Kinetics of the hydrolysis of 3-(2'-chloro-6'-fluorobenzyl) isocoumarin (1), 3-(4'-fluorophenyl)isocoumarin (3), 3-(2'- fluorophenyl)isocoumarin (5), 3-(2'-chlorophenyl)isocoumarin (7), and 3-(4'-chlorophenyl)isocoumarin (9) were studied spectrophotometrically in the presence of aqueous solution of potassium hydroxide. The rates of hydrolyses for these isocoumarins were compared. The data for isocoumarin (1) were further investigated to probe the reaction mechanism. The dependence of pseudo-first order rate constant k_{obs} on hydroxide ion concentration is fitted by the expression k_{obs} = k_o + k_1[OH] + k_2 [OH]^2, showing the formation of monoanionic and dianionic tetrahedral intermediates during the course of reaction. The magnitude of k_o shows significant participation of solvent …


Synthesis, Characterisation, And Structural Elucidation By Spectral Investigation (Ft-Ir, Multinuclear Nmr, Mass Spectrometry) Of Biologically Active Organotin(Iv) Compounds Containing Germanium, Muhammad Kaleem Khosa, Muhammad Mazhar, Saqib Ali, Sarim Dastgir Jan 2010

Synthesis, Characterisation, And Structural Elucidation By Spectral Investigation (Ft-Ir, Multinuclear Nmr, Mass Spectrometry) Of Biologically Active Organotin(Iv) Compounds Containing Germanium, Muhammad Kaleem Khosa, Muhammad Mazhar, Saqib Ali, Sarim Dastgir

Turkish Journal of Chemistry

A new series of di and tri-organotin(IV) compounds containing germanium with the general formula R_{4-n}SnL_n was synthesised by reaction of 3-triphenylgermanyl-3,3-dimethylpropionic acid with organotin(IV) oxides and organotin(IV) chloride in 2:1 and 1:1 molar ratio, respectively, where R~=~CH_3, C_2H_5, n-C_4H_9, n-C_8H_{17}, and C_6H_5 n = 1 or 2 and L~=~triphenylgermanyl acid anion (GeC_{23} H_{23} O_2^-). These compounds were characterised by elemental analyses, FT-IR, multinuclear NMR (^1H, ^{13}C, ^{119}Sn), and mass spectrometry. The geometry around the tin atom was determined and compared in both solution and solid states. The spectroscopic results indicated that all the diorganotin(IV) compounds containing germanium possess trigonal-bipyramidal structures …


Asymmetric Synthesis Of 8-O-4'-Neolignan Perseal B, Yamu Xia, Wei Wang, Yinglan Guo, Junfeng Li Jan 2010

Asymmetric Synthesis Of 8-O-4'-Neolignan Perseal B, Yamu Xia, Wei Wang, Yinglan Guo, Junfeng Li

Turkish Journal of Chemistry

Full details of an enantioselective total synthesis of 8-O-4'-neolignan perseal B are presented for the first time. The synthesis was achieved in 8 steps from vanillin and involved the asymmetric dihydroxylation reaction using AD-mix-\alpha to give the key intermedium (1S,2S)-1-(4-(benzyloxy)-3-methoxyphenyl)propane-1,2,3- triol, and the Mitsunobu reaction between phenylpropanoid and vanillin formed perseal B. The synthetic method of perseal B exhibits a new route for 8-O-4'-neolignan.


Molecular Recognition Of Aromatic Amines By Coumarin Substituted Azacrown Ether, Hiten Mehta, Harjinder Kaur, Shobhana Menon Jan 2010

Molecular Recognition Of Aromatic Amines By Coumarin Substituted Azacrown Ether, Hiten Mehta, Harjinder Kaur, Shobhana Menon

Turkish Journal of Chemistry

New chromogenic azacrown ether N[7-hydroxy-4-methyl-coumarin-8-methylene]-4-azadibenzo-18-crownether (HMCMADCE) was synthesised through the condensation reaction of 4-azadibenzo-18-crown- 6ether, 4-methyl,7-hydroxy coumarin and formaldehyde was used to investigate its behaviour towards the aromatic amines. All the aromatic primary amines gave specific colours in aqueous medium. The functional group recognition behaviour is further extended to study the estimation of the aromatic primary amine in commercial drug samples. The amines can be estimated in the presence of several functional groups like phenolic-OH, secondary and tertiary aromatic amines as well as aliphatic amines.


Synthesis And Characterization Of Hybrid Congo Red From Chloro-Functionalized Silsesquioxanes, Ahmet Gültek Jan 2010

Synthesis And Characterization Of Hybrid Congo Red From Chloro-Functionalized Silsesquioxanes, Ahmet Gültek

Turkish Journal of Chemistry

Congo red dye has been bonded to the functionalized octameric polyhedral silsesquioxanes (POSS), which were prepared by hydrolytic condensation of chloro-functionalized organosilicon monomers in the presence of a catalyst. The binding reaction of congo red to the POSS with chloro groups was achieved via the addition of the congo red via NaCl elimination. The structures of POSS with chloro side groups provided an attractive site for binding congo red that not only retains some of its characteristic properties, but also has exceptional hybrid properties possessed by the silica. The dye characteristics of the material were determined by means of UV …


Mannich Base Derivatives Of 3-Hydroxy-6- Methyl-4h-Pyran-4-One With Antimicrobial Activity, Demet Us, Barkin Berk, Eni̇se Ece Gürdal, Ni̇han Ayteki̇n, Zühtü Tanil Kocagöz, Berrak Çağlayan, Işil Kurnaz, Di̇lek Demi̇r Erol Jan 2010

Mannich Base Derivatives Of 3-Hydroxy-6- Methyl-4h-Pyran-4-One With Antimicrobial Activity, Demet Us, Barkin Berk, Eni̇se Ece Gürdal, Ni̇han Ayteki̇n, Zühtü Tanil Kocagöz, Berrak Çağlayan, Işil Kurnaz, Di̇lek Demi̇r Erol

Turkish Journal of Chemistry

A series of 3-hydroxy-6-methyl-2-[(substitutedpiperidine-1-yl) methyl]-4H-pyran-4-one structured compounds were synthesized by reacting 5-hydroxy-2-methyl-4H-pyran-4-one with suitable piperidine derivatives using Mannich reaction conditions. Antibacterial activities of the compounds for E. coli ATCC 25922, S. paratyphi ATCC BAA-1250, S. flexneri ATCC 12022, E. gergoviae ATCC 33426, and M. smegmatis ATCC 14468 were assessed in vitro by the broth dilution method for determination of minimum inhibitory concentration (MIC). In addition, their inhibitory effects over DNA gyrase enzyme were evaluated using a DNA gyrase supercoiling assay. All the synthesized compounds showed a MIC value of either 8 or 16 \mu g/mL for M. smegmatis, whereas minimum …


Electrochemical Properties Of 1-(O-, M-, P-Nitrophenyl)-3-(M-Nitrophenyl)- 5-Phenylformazans And Their Nickel Complexes, Habi̇be Tezcan, Mehmet Levent Aksu Jan 2010

Electrochemical Properties Of 1-(O-, M-, P-Nitrophenyl)-3-(M-Nitrophenyl)- 5-Phenylformazans And Their Nickel Complexes, Habi̇be Tezcan, Mehmet Levent Aksu

Turkish Journal of Chemistry

The electrochemical properties of NO_2 formazans and their Ni(II) complexes were investigated. The investigated formazans included a NO_2 group at the o-, m-, and p-positions of the 1-phenyl ring and at the m-position of the 3-phenyl ring. The oxidation and reduction peak potentials, number of electrons transferred, diffusion coefficient, heterogeneous rate constant, and possible reaction mechanism of the compounds were determined with the use of cyclic voltammetry (CV), ultramicrodisc electrodes (UMEs), and chronoamperometry (CA). The peak potentials (E}_{ox1}) were observed to shift towards more anodic potentials in formazans and more cathodic potentials in their respective Ni complexes compared to unsubstituted …


(E)-3-[(3-(Trifluoromethyl)Phenylimino)Methyl] Benzene-1,2-Diol: X-Ray And Dft Calculated Structures, Başak Koşar, Çi̇ğdem Albayrak, Mustafa Odabaşoğlu, Orhan Büyükgüngör Jan 2010

(E)-3-[(3-(Trifluoromethyl)Phenylimino)Methyl] Benzene-1,2-Diol: X-Ray And Dft Calculated Structures, Başak Koşar, Çi̇ğdem Albayrak, Mustafa Odabaşoğlu, Orhan Büyükgüngör

Turkish Journal of Chemistry

The crystal structure of (E)-3-[(3-(Trifluoromethyl)phenylimino)- methyl]benzene-1,2-diol was determined using X-ray diffraction and the molecular structure was investigated with density functional theory (DFT). The X-ray study showed that the title compound has a strong intramolecular O-H...N hydrogen bond and 3-dimensional crystal networks are primarily determined by O-H...O intermolecular hydrogen bonds and weak van der Waals interactions. The strong O-H...N bond is evidence of the preference for the phenol-imine tautomeric form in the solid state. Optimized molecular geometry was calculated with DFT at the B3LYP/6-31G(d,p) level. The results from both experiment and theoretical calculations for the title compound are compared with each …


Evaluation Of Solid-Phase Extraction Sorbent With Ketoimine Groups For The Preconcentration Of Benzene And Phenolic Compounds In Water, Iwona Rykowska, Wieslaw Wasiak Jan 2010

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%.


Synthesis And Spectroscopic Studies Of Some New Organometallic Chelates Derived From Bidentate Ligands, Kiran Singh, Parvesh Puri Jan 2010

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.


Preparation And Characterization Of Anticancer Drug-Loaded Implantable Plga Microparticles, Meltem Çeti̇n, İmran Vural, Alptuğ Ati̇la, Yücel Kadioğlu Jan 2010

Preparation And Characterization Of Anticancer Drug-Loaded Implantable Plga Microparticles, Meltem Çeti̇n, İmran Vural, Alptuğ Ati̇la, Yücel Kadioğlu

Turkish Journal of Chemistry

This article describes the preparation and characterization of anticancer drug-loaded poly(lactide-co-glycolide) (PLGA) microparticles. PLGA microparticles loaded with doxorubicin HCl (DOX) were prepared via o/w emulsion solvent evaporation. The release characteristics, encapsulation efficiency, size, and morphology of the PLGA microparticles were also determined. A cytotoxicity test was performed by using Glioma RG2 cancer cells to investigate the cytotoxicity of DOX-loaded PLGA microparticles. The DOX-loaded PLGA microparticles had an average diameter of 500 \pm 9 nm. The DOX encapsulation efficiency and drug loading were 22.75% and 0.78%, respectively. DOX-loaded PLGA microparticles displayed a significant cytotoxicity toward the RG2 cells as compared to …


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 Jan 2010

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. …


Silica Supported Polyphosphoric Acid (Ppa-Sio_2): An Efficient And Reusable Heterogeneous Catalyst For The One-Pot Synthesis Of \Alpha -Amino Phosphonates, Malek Taher Maghsoodlou, Sayyed Mostafa Habibi-Khorassani, Reza Heydari, Nourollah Hazeri, Seyed Sajad Sajadikhah, Mohsen Rostamizadeh, Leila Keishams Jan 2010

Silica Supported Polyphosphoric Acid (Ppa-Sio_2): An Efficient And Reusable Heterogeneous Catalyst For The One-Pot Synthesis Of \Alpha -Amino Phosphonates, Malek Taher Maghsoodlou, Sayyed Mostafa Habibi-Khorassani, Reza Heydari, Nourollah Hazeri, Seyed Sajad Sajadikhah, Mohsen Rostamizadeh, Leila Keishams

Turkish Journal of Chemistry

An efficient green protocol is described for the preparation of \alpha -amino phosphonates, employing a one-pot three-component condensation reaction between aldehydes, amines, and trialkyl phosphites in the presence of PPA-SiO_2 under solvent-free conditions at 80 °C. The present procedure offer advantages such as high to excellent yields, short reaction time, inexpensiveness, recovery, and reusability of catalyst.


Surfactant-Controlled Aqueous Synthesis Of Sno_2 Nanoparticles Via The Hydrothermal And Conventional Heating Methods, Muhammad Akhyar Farrukh, Heng Boon Teck, Rohana Adnan Jan 2010

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 …


Preparation Of Polystyrene/Montmorillonite Nanocomposites: Optimization By Response Surface Methodology (Rsm), Sadik Erdem Yalçinkaya, Nuray Yildiz, Mehmet Saçak, Ayla Çalimli Jan 2010

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, …