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2011

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Articles 901 - 930 of 1068

Full-Text Articles in Chemistry

A Study Of Behavior Of Some 5-Substituted- 4-Phenyl-1,2,4-Triazoline-3-Thiones In Sulfuric Acid Solution Using Characteristic Vector Analysis, Vesna Dimova Jan 2011

A Study Of Behavior Of Some 5-Substituted- 4-Phenyl-1,2,4-Triazoline-3-Thiones In Sulfuric Acid Solution Using Characteristic Vector Analysis, Vesna Dimova

Turkish Journal of Chemistry

The protonation process of 1,2,4-triazoline-3-thiones (T3T) was studied in aqueous sulfuric acid using the UV method. Characteristic vector analysis (CVA) was used to reconstruct the experimentally obtained UV spectra, to overcome difficulties in calculating the protonation constants of T3T, and to separate the effect of protonation from the generalized medium effect. pK_{TH}+ values were calculated using the Hammett acidity function method, the Bunnett and Olsen method, and the excess acidity function method. The obtained values for m, \phi and m* were close to those characteristic for similar thio compounds, indicating that the protonation site in the molecule of T3T is …

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A Simple And Rapid Spectrophotometric Determination Of Trace Level Simple And Rapid Spectrophotometric Determination Of Trace Level Chromium Using Bis (Salicylaldehyde) Orthophenylenediamine In Nonionic Micellar Media, Rubina Soomro, Jamaluddin Ahmed, Najma Memon Jan 2011

A Simple And Rapid Spectrophotometric Determination Of Trace Level Simple And Rapid Spectrophotometric Determination Of Trace Level Chromium Using Bis (Salicylaldehyde) Orthophenylenediamine In Nonionic Micellar Media, Rubina Soomro, Jamaluddin Ahmed, Najma Memon

Turkish Journal of Chemistry

Bis(salicylaldehyde)orthophenylenediamine (BSOPD) has been proposed as new analytical reagent for the direct spectrophotometric determination of chromium. It reacts with chromium(VI) in slightly acidic (0.1 -- 0.3 M H_2SO_4) micellar medium to form a yellow - orange chelate with a molar ratio 2:3. The most remarkable point of this method is that the molar absorptivities of the Cr^{VI} -- BSOPD complex formed in the presence of nonionic TritonX -- 100 surfactant are almost 10 times higher than the value observed in aqueous solution. This results in enhancing the sensitivity and selectivity of the method. The reaction is instantaneous and the maximum …

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Controlled Growth Of Two-Dimensional Copper Nanoplates In Graphite Gallery, Xiaobei Bin, Jiazang Chen, Hong Cao Jan 2011

Controlled Growth Of Two-Dimensional Copper Nanoplates In Graphite Gallery, Xiaobei Bin, Jiazang Chen, Hong Cao

Turkish Journal of Chemistry

Copper nanoplates embedded in a graphite gallery were obtained by in situ reduction of stage 1, stage 2, and stage 3 CuCl_2-graphite intercalation compound precursors. The characterization results indicated that the morphology of the copper species was that of a 2-dimensional or quasi-2-dimensional nanoplate in the graphite gallery. Interaction between the metallic nanoplates and graphene sheet was also detected. The hexagonal graphene network restricted the crystallization orientation of the copper nanoparticles, and, at the same time, the finite space between the graphene sheets prevented the increase of the thickness. This method would provide a convenient route to synthesize or assemble …

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Assimilable Organic Carbon Generation From Algogenic Organic Matter In Drinking Water, Ji-Hoon Kim, Young-Ju Kim, Tahir Imran Qureshi Jan 2011

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 …

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Synthesis, Characterization, And Biological Activity Studies Of (E)-N'-((Thiophen-2-Yl)Methylene)Benzofuran-2-Carbohydrazide And Its Metal(Ii) Complexes, Madappa B. Halli, Vijayalaxmi B. Patil, Sumathi R. Bevinamarada Jan 2011

Synthesis, Characterization, And Biological Activity Studies Of (E)-N'-((Thiophen-2-Yl)Methylene)Benzofuran-2-Carbohydrazide And Its Metal(Ii) Complexes, Madappa B. Halli, Vijayalaxmi B. Patil, Sumathi R. Bevinamarada

Turkish Journal of Chemistry

Metal complexes of the type MLX_2, where M = Co(II), Ni(II), Cu(II), Zn(II), Cd(II), and Hg(II), and X = Cl and L = TMBC, Schiff base derived from the condensation of benzofuran-2-carbohydrazide with thiophene-2-aldehyde were synthesized. The structure of the complexes was proposed in light of analytical, IR, UV-Vis, ^1H-NMR, FAB-MS, ESR spectral data, and magnetic studies. The complexes were soluble in DMF and DMSO. The measured molar conductance values indicated that the complexes were nonelectrolytic in nature. On the basis of these studies, 6 coordinated octahedral polymeric structures were assigned to the Co(II), Ni(II), and Cu(II) complexes, and 4 …

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Synthesis And Characterization Of New Symmetrical 3,6-Bis[(25,26,27- Tripropoxy-28-(3-(4-Iodophenyl) Propoxy)-P-Tert-Butyl Calix[4]Arene Ethynyl]-9h- Fluoren-9-One By Sonogashira Coupling As A Novel Precursor For Synthesis Of Quinodimethane (Qdm), Karim Akbari Dilmaghani, Fazel Nasuhi Pur Jan 2011

Synthesis And Characterization Of New Symmetrical 3,6-Bis[(25,26,27- Tripropoxy-28-(3-(4-Iodophenyl) Propoxy)-P-Tert-Butyl Calix[4]Arene Ethynyl]-9h- Fluoren-9-One By Sonogashira Coupling As A Novel Precursor For Synthesis Of Quinodimethane (Qdm), Karim Akbari Dilmaghani, Fazel Nasuhi Pur

Turkish Journal of Chemistry

Novel symmetrical 3,6-bis[(25,26,27-tripropoxy-28-(3-(4-iodophenyl)propoxy)-p-tert-butyl calix[4]arene ethynyl]-9H-fluoren-9-one with a cone conformation was synthesized by palladium-catalyzed coupling of (25,26,27-tripropoxy- 28-(3-(4-iodophenyl)propoxy)-p-tert-butyl calix[4]arene and 3,6-diethynyl-9H-fluoren-9-one. Its structure was confirmed by FT-IR, ^1H-NMR, and ^{13}C-NMR spectroscopy, and elemental analysis and positive ion FAB mass spectrometry.

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A Near-Infrared Fluorescent Sensor For H^+ In Aqueous Solution And Living Cells, Aibin Wu, Liping Duan Jan 2011

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.

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Synthesis And Structural Analysis Of A Regular Cu-Mg-Al Hydrotalcite-Like Compound, Jiansong Wu, Yingkai Xiao, Yuping Liu, Wanbang Xu, Meifang Liang, Jian Cheng, Jianping Wan, Lingzhu Chen Jan 2011

Synthesis And Structural Analysis Of A Regular Cu-Mg-Al Hydrotalcite-Like Compound, Jiansong Wu, Yingkai Xiao, Yuping Liu, Wanbang Xu, Meifang Liang, Jian Cheng, Jianping Wan, Lingzhu Chen

Turkish Journal of Chemistry

A fine-quality, regular Cu-Mg-Al hydrotalcite-like compound was synthesized via the glycothermal method using CuCl_2 \cdot 2H_2O, MgCl_2 \cdot 6H_2O, AlCl_3 \cdot 6H_2O, and Na_2CO_3 as raw materials and sodium hydroxide as the precipitant. Hydrotalcite samples were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, thermogravimetric-differential thermal analysis, and Brunauer-Emmett-Teller N_2 surface area measurements. The influence of glycol content on the characteristics of the sample was investigated. The results show that the glycol content in the system had a greater impact on regular hydrotalcite with an intercalated structure. A Cu-Mg-Al hydrotalcite-like compound with a well-defined …

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Imaging The Extracellular Ph Of Tumors By Mri After Injection Of A Single Cocktail Of T1 And T2 Contrast Agents, Gary V. Martinez, Xiaomeng Zhang, María L. García-Martín, David L. Morse, Mark Woods, A. Dean Sherry, Robert J. Gillies Jan 2011

Imaging The Extracellular Ph Of Tumors By Mri After Injection Of A Single Cocktail Of T1 And T2 Contrast Agents, Gary V. Martinez, Xiaomeng Zhang, María L. García-Martín, David L. Morse, Mark Woods, A. Dean Sherry, Robert J. Gillies

Chemistry Faculty Publications and Presentations

The extracellular pH (pH(e) ) of solid tumors is acidic, and there is evidence that an acidic pH(e) is related to invasiveness. Herein, we describe an MRI single-infusion method to measure pH(e) in gliomas using a cocktail of contrast agents (CAs). The cocktail contained gadolinium-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraaminophosphonate (GdDOTA-4AmP) and dysprosium-1,4,7,10-tetraazacyclododecane-N,N',N'',N'''-tetrakis(methylenephosphonic acid) (DyDOTP), whose effects on relaxation are sensitive and insensitive to pH, respectively. The Gd-CA dominated the spin-lattice relaxivity ΔR(1) , whereas the Dy-CA dominated the spin-spin relaxivity ΔR(2)*. The ΔR(2)* effects were used to determine the pixel-wise concentration of [Dy] which, in turn, was used to calculate a value for [Gd] …

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Epitaxial Electrodeposition Of Metal Oxide Films And Superlattices Which Exhibit Resistance Switching, Rakesh V. Gudavarthy Jan 2011

Epitaxial Electrodeposition Of Metal Oxide Films And Superlattices Which Exhibit Resistance Switching, Rakesh V. Gudavarthy

Doctoral Dissertations

"This dissertation presents an investigation of the electrodeposition of metal oxide films and superlattices on conducting polycrystalline and single crystal substrates. In the first part of the study, electrodeposition of magnetite (Fe₃O₄) films and superlattices in the magnetite/zinc ferrite system which exhibit resistance switching is studied. Paper I reports the electrodeposition of superlattices in the magnetite/zinc ferrite system and shows that only superlattices exhibit multistate resistance switching. In paper II, simple polycrystalline magnetite films electrodeposited on stainless steel crystals exhibit multistate resistance switching which can be tuned by controlling the composition of the films. Paper II describes the epitaxial electrodeposition …

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Relaxation Imaging To Characterize Lightweight Polymer-Crosslinked Aerogels, Emmalou T. Satterfield Jan 2011

Relaxation Imaging To Characterize Lightweight Polymer-Crosslinked Aerogels, Emmalou T. Satterfield

Masters Theses

"Silica aerogels are three-dimensional assemblies of silica nanoparticles with extremely low densities. In some instances, the internal void volume is more than 90% of the total volume. The highly porous structure of the aerogels leads to attractive properties for thermal and noise insulation, due to very low thermal conductivity and very high acoustic impedance. The strength of silica aerogels has been substantially improved by casting a thin conformal polymer coating over the entire internal porous surfaces of the nanostructure. The coating reinforces the interparticle connections without significantly compromising the internal void space. To analyze and compare the properties of several …

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Synthesis Of Some 2,3,6,8-Tetraarylimidazo[1,2-A]Pyrazine Derivatives By Using Either Reflux Or Microwave Irradiation Method, And Investigation Their Anticancer Activities, İsmai̇l Kayaği̇l, Şeref Demi̇rayak Jan 2011

Synthesis Of Some 2,3,6,8-Tetraarylimidazo[1,2-A]Pyrazine Derivatives By Using Either Reflux Or Microwave Irradiation Method, And Investigation Their Anticancer Activities, İsmai̇l Kayaği̇l, Şeref Demi̇rayak

Turkish Journal of Chemistry

In this study, some 2,3,6,8-tetraarylimidazo[1,2-a]pyrazine derivatives were synthesized by reacting 1-(2-aryl-2-oxoethyl)-2-aryloyl-4,5-diarylimidazoles from 2-aryloyl-4,5-diarylimidazole and 2-bromoacetophenone derivatives with ammonium acetate in acetic acid by using the method that was previously developed and repeatedly tested in our studies. Structural elucidation of the compounds was performed by IR, ^1H-NMR, and MASS spectroscopic data and elemental analysis results. Anticancer activities of selected compounds were evaluated and the noticeable activity values were reported.

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Effect Of Cmc And Hpc Mixture On The Photocatalytic Activity Of Nd-Tio_2/Sio_2 Film Under Visible Light Irradiation, Parviz Aberoomand, Shahram Moradi, Susan Samadi, Mohammad Saber Tehrani, Mohammad Hadi Givianrad Jan 2011

Effect Of Cmc And Hpc Mixture On The Photocatalytic Activity Of Nd-Tio_2/Sio_2 Film Under Visible Light Irradiation, Parviz Aberoomand, Shahram Moradi, Susan Samadi, Mohammad Saber Tehrani, Mohammad Hadi Givianrad

Turkish Journal of Chemistry

Neodymium-titania/silica films were prepared by the sol-gel method with the addition of various amounts of hydroxy propyl cellulose (HPC) and 5.09 \times 10^{-5} g g^{-1}_{solution} of carboxy methyl cellulose (CMC) in saturated conditions. The porous Nd-TiO_2/SiO_2 was obtained after heat treatment for 2 h at 500 °C, with the surface area up to 276 m^2 g^{-1}, which was measured using the Brunauer, Emmett, and Teller (BET) method. Scanning electron microscopy (SEM) showed that the particle size of Nd-TiO_2/SiO_2 decreased and the microstructure of the film became loose in suitable conditions with the addition of CMC to HPC. Subsequently, the photocatalytic …

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Synthesis And Evaluation Of The Analgesic Activity Of Some New Isoxazolo[4,5-D]Pyridazin-4(5h)-One Derivatives, Oya Ünsal Tan, Keri̇man Özadali, Özgür Yeşi̇lyurt, Hakan Kayir, İsmai̇l Tayfun Uzbay, Ayla Balkan Jan 2011

Synthesis And Evaluation Of The Analgesic Activity Of Some New Isoxazolo[4,5-D]Pyridazin-4(5h)-One Derivatives, Oya Ünsal Tan, Keri̇man Özadali, Özgür Yeşi̇lyurt, Hakan Kayir, İsmai̇l Tayfun Uzbay, Ayla Balkan

Turkish Journal of Chemistry

Some isoxazolo[4,5-d]pyridazin4(5H)-one derivatives were synthesized and tested for their analgesic activity. The analgesic activities of the compounds were determined by hot-plate and acetic acid writhing tests using morphine and diclofenac as references. Compounds 4a, 4f, 4g, and 4i (25 mg/kg) showed analgesic profiles similar to that of morphine (5 mg/kg).

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Synthesis, Crystal Structure, And Antioxidant Properties Of Novel 1,2,4-Triazol-5-Ones Containing 3,4-Dimethoxyphenyl And 3,4-Dihydroxyphenyl Moiety, Yasemi̇n Ünver, Sevgi̇ Meydanal, Kemal Sancak, Di̇lek Ünlüer, Reşat Ustabaş, Esra Düğdü Jan 2011

Synthesis, Crystal Structure, And Antioxidant Properties Of Novel 1,2,4-Triazol-5-Ones Containing 3,4-Dimethoxyphenyl And 3,4-Dihydroxyphenyl Moiety, Yasemi̇n Ünver, Sevgi̇ Meydanal, Kemal Sancak, Di̇lek Ünlüer, Reşat Ustabaş, Esra Düğdü

Turkish Journal of Chemistry

A series of new 4-(3,4-dimethoxyphenethyl)-5-akyl/aryl-2H- 1,2,4-triazol-3(4H)-ones (3a-g) was obtained by the reaction of ethyl 2-(ethoxy)(alkylidene/arylidene)hydrazinecarboxylate (1) and 2-(3,4-dimethoxyphen- yl)ethanamine (2). Compounds 4a-f and 5 were synthesized from the reaction of corresponding compounds 3a-f and 3g with BBr_3, respectively. With elemental analysis, IR, ^1H-NMR, and ^{13C-NMR spectral data, 14 newly synthesized compounds were characterized. The structure of compound 3a was inferred through IR, ^1H- and ^{13}C-NMR, elemental analysis, and X-ray spectral techniques. In addition, the newly synthesized chemicals were screened for their antioxidant properties. Among the chemicals tested, 4a, 4c, 4d, 4f, and 5 exhibited the highest degree of antioxidant activity.

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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 Jan 2011

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. …

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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 Jan 2011

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).

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Bromination Of 2,3-Dihydrobenzobarrelene And Synthesis Of Its Mono- And Dibromide Derivatives: Unexpected Wagner-Meerwein Rearrangement On Silica Gel, Selçuk Eşsi̇z, Mehmet Emi̇n Şengül, Ertan Şahi̇n, Ari̇f Daştan Jan 2011

Bromination Of 2,3-Dihydrobenzobarrelene And Synthesis Of Its Mono- And Dibromide Derivatives: Unexpected Wagner-Meerwein Rearrangement On Silica Gel, Selçuk Eşsi̇z, Mehmet Emi̇n Şengül, Ertan Şahi̇n, Ari̇f Daştan

Turkish Journal of Chemistry

The bromination reaction of dihydrobenzobarrelene under different conditions was studied. The bromination reaction of dihydrobenzobarrelene with molecular bromine gave only a Wagner-Meerwein rearrangement product by aryl and alkyl migration. Its high-temperature bromination reaction resulted in the formation of normal addition products besides rearrangement products. The bromination reaction of the alkene with 1,2- dibromotetrachloroethane (DBTCE) gave a non-rearrangement product as the sole product. The synthesis and bromination reaction of 2-bromodihydrobenzobarrelene was also studied. An unexpected Wagner-Meerwein rearrangement was observed on silica gel during the column chromatography of isomeric tribromides. Herein, we report the results of the synthesis, and the X-ray crystal …

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Synthesis Of Novel Tetraoxime Derivative With Hydrazone Side Groups And Its Metal Complexes, İlknur Babahan, Hüseyi̇n Anil, Nursabah Sarikavakli Jan 2011

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.

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Antioxidant Phenolics From Lobaria Pulmonaria (L.) Hoffm. And Usnea Longissima Ach. Lichen Species, Fadi̇me Atalay, Mesut Bünyami̇ Halici, Ahmet Mavi̇, Ahmet Çakir, Fehmi̇ Odabaşoğlu, Cavi̇t Kazaz, Ali̇ Aslan, Ömer İrfan Küfrevi̇oğlu Jan 2011

Antioxidant Phenolics From Lobaria Pulmonaria (L.) Hoffm. And Usnea Longissima Ach. Lichen Species, Fadi̇me Atalay, Mesut Bünyami̇ Halici, Ahmet Mavi̇, Ahmet Çakir, Fehmi̇ Odabaşoğlu, Cavi̇t Kazaz, Ali̇ Aslan, Ömer İrfan Küfrevi̇oğlu

Turkish Journal of Chemistry

In this study, 1 steroidal and 8 phenolic compounds from Lobaria pulmonaria (L.) Hoffm. and Usnea longissima Ach. were isolated and their chemical structures were characterized by ^1H-NMR, ^{13}C-NMR, DEPT, ^1H-^1H COSY, HMQC, HMBC, IR, UV, and MS spectroscopic methods as stictic acid, isidiophorin, rhizonaldehyde, rhizonyl alcohol, pulmonarianin, vesuvianic acid, ergosterol peroxide, usnic acid, and diffractaic acid. Among these compounds, pulmonarianin, isolated from L. pulmonaria, was characterized for the first time as a natural compound. In addition to isolation and characterization, the lipid peroxidation inhibition and DPPH radical scavenging activities of the isolated compounds were investigated. Among these compounds, isidiophorin, …

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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 Jan 2011

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.

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Simultaneous Determination Of Copper And Cadmium In Environmental Water And Tea Samples By Adsorptive Stripping Voltammetry, Mohammad Bagher Gholivand, Alireza Pourhossein, Mohsen Shahlaei Jan 2011

Simultaneous Determination Of Copper And Cadmium In Environmental Water And Tea Samples By Adsorptive Stripping Voltammetry, Mohammad Bagher Gholivand, Alireza Pourhossein, Mohsen Shahlaei

Turkish Journal of Chemistry

A sensitive and selective method for the simultaneous determination of copper and cadmium in seawater, river water, and tea samples is described. The method is based on the adsorptive accumulation of 2,2--dithiosalicylic acid complexes of these elements onto a hanging mercury drop electrode, followed by reduction of adsorbed species by voltammetric scan using differential pulse modulation. Optimal analytical conditions were as follows: ligand concentration of 11 nM, pH of 9.5, and an adsorption potential at --300 mV versus Ag/AgCl, with an accumulation time of 60 s. The peak currents are proportional to the concentration of copper and cadmium over the …

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The Sorption Of Cadmium(Ii) Ions On Mercerized Rice Husk And Activated Carbon, Mas Rosemal Hakim Mas Haris, Nor Aimi Abdul Wahab, Chong Wan Reng, Baharin Azahari, Kathiresan Sathasivam Jan 2011

The Sorption Of Cadmium(Ii) Ions On Mercerized Rice Husk And Activated Carbon, Mas Rosemal Hakim Mas Haris, Nor Aimi Abdul Wahab, Chong Wan Reng, Baharin Azahari, Kathiresan Sathasivam

Turkish Journal of Chemistry

This work describes the removal of Cd(II) ions in aqueous solution by unmodified and base-modified rice husk (RH) as compared to that by activated carbon (AC). Mercerization of RH was carried out by using dilute solutions (0.013 M) of NaOH, KOH, and Ca(OH)_2. The experiments were conducted in duplicate under 1-batch and 2-batch treatments. In the 1-batch treatment, a fresh 200 mg of each adsorbent was used to study the sorption of the Cd(II) ions from 100-mL solutions at an initial concentration of 5 mg L^{-1}. The adsorption percentage increased in the order of unmodified RH (80.13 \pm 0.46%) < Ca(OH)_2-modified RH (90.74 \pm 0.18%) < NaOH-modified RH (93.36 \pm 0.23%) \le KOH-modified RH (93.78 \pm 0.27%) < AC (98.4 \pm 0.18%). In the 2-batch treatment, a fresh 100 mg of each adsorbent was placed in 100-mL solutions at an initial concentration of 5 mg L^{-1} of Cd(II) ions for 30 min, and the resulting solutions were filtered. The filtrates were subjected to another fresh 100 mg of each adsorbent for an additional 30 min. The percentage removal of the metal ion using the 2-batch treatment for unmodified RH, base-modified RH, and AC was 97.71%, 98.00 \pm 1.00%, and nearly 100%, respectively.

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Performance Evaluation Of A Novel Asymmetric Capacitor Using A Light-Weight, Carbon Foam Supported Nickel Electrode, Padmanaban Sasthan Kuttipillai Jan 2011

Performance Evaluation Of A Novel Asymmetric Capacitor Using A Light-Weight, Carbon Foam Supported Nickel Electrode, Padmanaban Sasthan Kuttipillai

Dissertations, Master's Theses and Master's Reports - Open

Electrochemical capacitors have been an important development in recent years in the field of energy storage. Capacitors can be developed by utilizing either double layer capacitance at the electrode/solution interfaces alone or in combination with a battery electrode associated with a faradic redox process in one electrode. An asymmetric capacitor consisting of electrochemically deposited nickel hydroxide, supported on carbon foam as a positive electrode and carbon sheet as a negative electrode has been successfully assembled and cycled. One objective of this study has been to demonstrate the viability of the nickel carbon foam positive electrode, especially in terms of cycle …

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New Photovoltaic Acceptors: Synthesis And Characterization Of Functionalized C-Fused Anthradithiophene Quinones, Kerri Shelton Jan 2011

New Photovoltaic Acceptors: Synthesis And Characterization Of Functionalized C-Fused Anthradithiophene Quinones, Kerri Shelton

University of Kentucky Master's Theses

Stable organic semiconductors are critical to produce inexpensive, efficient and flexible thin film organic solar cells. A current chemical focus is the synthesis of stable, electron-accepting materials to be utilized as an acceptor layer in photovoltaics.1 The Anthony group has shown that the functionalization of pentacene with suitable electron withdrawing groups provides a catalog of suitable acceptors for this purpose.2 These pentacenes can be further modified to pack in a unique 1-dimensional "sandwich herringbone" crystal packing, leading to improved device current.3 To improve the stability of acene acceptors, we have taken two hetero-atom themed approaches. First, we …

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Partially Halogenated Acenes And Heteroacenes For Organic Electronics, Balaji Purushothaman Jan 2011

Partially Halogenated Acenes And Heteroacenes For Organic Electronics, Balaji Purushothaman

University of Kentucky Doctoral Dissertations

Inorganic materials have dominated electronic applications such as photovoltaic cells, thin film transistors (TFTs) and light emitting diodes (LEDs). However developments in the field of organic electronics over the past three decades have enabled the use of organic materials in these devices. While significant improvements have been made to improve their electronic properties there are several road blocks towards commercial application. One of the significant obstacles is the poor charge carrier mobility associated with organic semiconductors processed by well established printing methods. The goal of my research project is to improve the charge carrier mobility of solution cast films of …

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Design And Construction Of A Reflectron Time Of Flight Mass Spectrometer For Multiphoton Ionization And Vibrational Spectroscopic Studies Of Mass-Selected Clusters, Matthew Dodd Mcdowell Jan 2011

Design And Construction Of A Reflectron Time Of Flight Mass Spectrometer For Multiphoton Ionization And Vibrational Spectroscopic Studies Of Mass-Selected Clusters, Matthew Dodd Mcdowell

Honors Theses

Mass spectrometry is typically employed for the elucidation and identification of elements and compounds. Its ability to select and isolate specific molecular clusters makes it an ideal tool for the fundamental spectroscopic study of the photophysical and geometric properties of molecules and molecular clusters. The design and construction of a reflectron time of flight mass spectrometer (reflectron TOF-MS) as well as its implementation for electronic and vibrational spectroscopic studies of various molecules and molecular clusters is discussed. The first chapter introduces basic theory related to electronic spectroscopy, multiphoton ionization, and vibrational spectroscopy. The second chapter entails the theoretical aspects of …

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Interactions And Effects Of Biomolecules On Au Nanomaterial Surfaces, Manish Sethi Jan 2011

Interactions And Effects Of Biomolecules On Au Nanomaterial Surfaces, Manish Sethi

University of Kentucky Doctoral Dissertations

Au nanoparticles are increasingly being used in biological applications. Their use is of interest based upon their unique properties that are achieved at the nanoscale, which includes strong optical absorbances that are size and aggregation state dependent. Such absorbances can be used in sensitive chemical/biological detection schemes where bioligands can be directly attached to the nanoparticle surface using facile methods. Unfortunately, a number of complications persist that prevent their wide-scale use. These limitations include minimal nanoparticle stability in biological-based media of high ionic strength, unknown surface functionalization effects using simple biomolecules, and determining the binding motifs of the ligands to …

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Periodic Trends In Structure Function Relationship Of Organic Heteroacenes, Marsha Loth Grimminger Jan 2011

Periodic Trends In Structure Function Relationship Of Organic Heteroacenes, Marsha Loth Grimminger

University of Kentucky Doctoral Dissertations

Our group has previously shown that small changes to molecular structure result in large changes to device properties and stability in organic electronic applications. By functionalizing aromatic heteroacenes with group 14 and group 16 elements, it is possible to control morphology and improve stability for a variety of applications such as thin film transistors and solar cells. Functionalization within the heteroacene core led to changes in electronic structure as observed by electrochemistry and light absorption. By substituting down the periodic table, the carbon heteroatom bond length increased, leading to subtle changes in crystal packing. Absorption maxima were red-­‐shifted and stability …

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Synthesis And Physicochemical Properties Of Cationic Microgels Based On Poly(N-Isopropylmethacrylamide), Xiaobo Hu, Zhen Tong, L. Andrew Lyon Jan 2011

Synthesis And Physicochemical Properties Of Cationic Microgels Based On Poly(N-Isopropylmethacrylamide), Xiaobo Hu, Zhen Tong, L. Andrew Lyon

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Surfactant-free, radical precipitation copolymerization of N-isopropylmethacrylamide and the cationic co-monomer N-(3-aminopropyl) methacrylamide hydrochloride (APMH) was carried out to prepare microgels functionalized with primary amines. The morphology and hydrodynamic diameter of the microgels were characterized by atomic force microscopy and photon correlation spectroscopy, with the effect of NaCl concentration and initiator type on the microgel size and yield being investigated. When a 2,2'-azobis (2-amidinopropane) dihydrochloride (V50)-initiated reaction was carried out in pure water, relatively small microgels (similar to 160 nm in diameter) were obtained in low yield (similar to 20%). However, both the yield and size increased if the reaction was …

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