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Chemistry Faculty Publications

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Articles 871 - 900 of 1129

Full-Text Articles in Chemistry

Volatile Organic Compounds Composition Of Merged And Aged Forest Fire Plumes From Alaska And Western Canada, Joost A. De Gouw, C. Warneke, A. Stohl, A. G. Wollny, C. A. Brock, O. R. Cooper, J. S. Holloway, M. Trainer, F. C. Fehsenfeld, E. L. Atlas, Stephen G. Donnelly Ph.D., V. Stroud, A. Lueb May 2006

Volatile Organic Compounds Composition Of Merged And Aged Forest Fire Plumes From Alaska And Western Canada, Joost A. De Gouw, C. Warneke, A. Stohl, A. G. Wollny, C. A. Brock, O. R. Cooper, J. S. Holloway, M. Trainer, F. C. Fehsenfeld, E. L. Atlas, Stephen G. Donnelly Ph.D., V. Stroud, A. Lueb

Chemistry Faculty Publications

The NOAA WP-3 aircraft intercepted aged forest fire plumes from Alaska and western Canada during several flights of the NEAQS-ITCT 2k4 mission in 2004. Measurements of acetonitrile (CH3CN) indicated that the air masses had been influenced by biomass burning. The locations of the plume intercepts were well described using emissions estimates and calculations with the transport model FLEXPART. The best description of the data was generally obtained when FLEXPART injected the forest fire emissions to high altitudes in the model. The observed plumes were generally drier than the surrounding air masses at the same altitude, suggesting that the fire plumes …

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10,10′-Dinitro-10,10′-(Propane-1,3-Di­Yl)Di-10h-Anthracen-9-One, Mustafa Arslan, Erol Asker, John Masnovi, Ronald J. Baker May 2006

10,10′-Dinitro-10,10′-(Propane-1,3-Di­Yl)Di-10h-Anthracen-9-One, Mustafa Arslan, Erol Asker, John Masnovi, Ronald J. Baker

Chemistry Faculty Publications

The title compound, C31H22N2O6, was obtained as the decomposition product of (E,E)-1,3-bis­[9,10-dihydro-9-nitro-10-(trinitro­meth­yl)-9-anthr­yl]propane, which was synthesized via a photochemical reaction of 1,3-di-9-anthrylpropane with tetra­nitro­methane. Inter­molecular C—H⋯O inter­actions are the most prominent features of the crystal packing; no indications of any inter­molecular π–π stacking were found.

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Platinum(Ii) Diimine Diacetylides: Metallacyclization Enhances Photophysical Properties, Fei Hua, Solen Kinayyigit, John R. Cable, Felix N. Castellano May 2006

Platinum(Ii) Diimine Diacetylides: Metallacyclization Enhances Photophysical Properties, Fei Hua, Solen Kinayyigit, John R. Cable, Felix N. Castellano

Chemistry Faculty Publications

The synthesis, structural characterization, and photoluminescence properties of a new platinum(II) diimine complex bearing the bidentate diacetylide ligand tolan- 2,2'-diacetylide (tda), Pt(dbbpy)( tda) [dbbpy) = 4,4'-di-tert-butyl-2,2'-bipyridine], are described. In CH2Cl2, Pt( dbbpy)( tda) exhibits a strong visible charge-transfer absorption and broad emission centered at 562 nm. The photoluminescence quantum yield and excited-state lifetime are 0.52 and 2.56 mu s, respectively, at room temperature. These parameters indicate that the planarization and rigidity introduced by the cyclic diacetylide leads to a lower-energy-absorbing species displaying enhanced photophysics relative to the analogous Pt( dbbpy)( C = CPh)(2). Time-dependent density functional theory calculations, which include …

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Secondary N-Nitrosocarbamate Anions: Structure And Alkylation Reactions. A Dft Study, Vladimir Benin May 2006

Secondary N-Nitrosocarbamate Anions: Structure And Alkylation Reactions. A Dft Study, Vladimir Benin

Chemistry Faculty Publications

The current article reports theoretical studies (DFT: B3LYP/6-31+G(d)) on the structure and alkylation reactions of the anions of some secondary N-nitrosocarbamates, a class of ambident nucleophiles whose chemistry has been little explored. Several anions (1–4), with an increasing size of the carbamate alkyl (aryl) group were investigated, in an attempt to establish the influence of the size of that group on the thermal stability and regioselectivity of alkylation of the title anions. The conclusion is that thermal stability and the mode of reaction are affected significantly only in the presence of very large and branched carbamate groups. The thermal …

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Nocturnal Odd-Oxygen Budget And Its Implications For Ozone Loss In The Lower Troposphere, Steven S. Brown, J. A. Neuman, T. B. Ryerson, M. Trainer, W. P. Dubé, J. S. Holloway, C. Warneke, J. A. De Gouw, Stephen G. Donnelly Ph.D., E. Atlas, B. Matthew, A. M. Middlebrook, R. Peltier, R. J. Weber, A. Stohl, J. F. Meagher, F. C. Fehsenfeld, A. R. Ravishankara Apr 2006

Nocturnal Odd-Oxygen Budget And Its Implications For Ozone Loss In The Lower Troposphere, Steven S. Brown, J. A. Neuman, T. B. Ryerson, M. Trainer, W. P. Dubé, J. S. Holloway, C. Warneke, J. A. De Gouw, Stephen G. Donnelly Ph.D., E. Atlas, B. Matthew, A. M. Middlebrook, R. Peltier, R. J. Weber, A. Stohl, J. F. Meagher, F. C. Fehsenfeld, A. R. Ravishankara

Chemistry Faculty Publications

Nitrogen oxides are important to the regulation of ozone throughout the Earth's atmosphere. Of particular interest for regional air quality is photochemical production and nocturnal destruction Of O3 in the lower troposphere in high NOx(=NO + NO2) environments. Nocturnal tropospheric odd oxygen (Ox), defined as O3 + NO2 + 2NO3 + 3N2O5, is used to assess the impact of NOx emissions on nocturnal O3 loss. Recent aircraft measurements of the components of Ox and HNO3 yield a detailed accounting of the nocturnal Ox budget in a regionally polluted environment. The analysis demonstrates the role of NO3 and N2O5 reactions in …

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9-Ethyl-3-(9h-9-Ethyl­Carbazol-3-Yl)-4-Nitro­-9h-Carbazole, Erol Asker, John Masnovi Apr 2006

9-Ethyl-3-(9h-9-Ethyl­Carbazol-3-Yl)-4-Nitro­-9h-Carbazole, Erol Asker, John Masnovi

Chemistry Faculty Publications

In the mol­ecule of the title compound, C28H23N3O2, the nitro group is almost perpendicular to the carbazole ring to which it is attached. The crystal packing is determined by C—H⋯O and π–π inter­actions, where the nitrated carbazole ring of one mol­ecule associates in a shifted parallel planar orientation with the centrosymmetrically related non-nitrated carbazole ring of a neighbouring mol­ecule.

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Bis(9-Ethyl­Carbazol-3-Yl)Ethane, Erol Asker, John Masnovi Apr 2006

Bis(9-Ethyl­Carbazol-3-Yl)Ethane, Erol Asker, John Masnovi

Chemistry Faculty Publications

In the title compound, C30H28N2, each carbazole skeleton is essentially planar. The planes of the two carbazole ring systems are nearly parallel, with a dihedral angle of 2.33 (19)°. The crystal packing is stabilized only by van der Waals forces and weak C—H⋯π inter­actions.

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Composition Ot Glvceride Esters Of Lauric Acid Bv Ftir Band Shape Analysis, Deniz P. Wong, Modesto Tan Chua, Erwin P. Enriquez Apr 2006

Composition Ot Glvceride Esters Of Lauric Acid Bv Ftir Band Shape Analysis, Deniz P. Wong, Modesto Tan Chua, Erwin P. Enriquez

Chemistry Faculty Publications

Synthesis of glyceride esters of a fatty acid produces a mixture of isomers that are difficult to separate and analyze, requiring high temperature GC in most cases particularly for long-chain esters. In this paper, we present a fast estimation of the composition of the glyceride esters of lauric acid and glycerol (monolaurin, dilaurin, and trilaurin) by FTIR band shape analysis. The method uses the fact that the carbonyl stretching regions of the pure glycerides have differentband shapes, which implies any composite band of a mixture of glycerides may be resolved into the component peaks due to each glyceride. The carbonyl …

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9,9′-Diethyl-3,3′-Di-9h-Carbazol­Yl, Erol Asker, John Masnovi Mar 2006

9,9′-Diethyl-3,3′-Di-9h-Carbazol­Yl, Erol Asker, John Masnovi

Chemistry Faculty Publications

In the title compound, C28H24N2, the carbazole ring systems are essentially planar to within 0.076 (3) Å. The dihedral angle between the planes of the ring systems is 40.38 (4)°. The contribution of inter­molecular π–π inter­actions to the mol­ecular stacking is observed.

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Bis(9-Ethyl­Carbazol-3-Yl)Methane, Erol Asker, John Masnovi Mar 2006

Bis(9-Ethyl­Carbazol-3-Yl)Methane, Erol Asker, John Masnovi

Chemistry Faculty Publications

In the title compound, C29H26N2, the carbazole ring systems are essentially planar. There is no indication of π–π interactions in the crystal structure, adjacent carbazole groups being non-parallel.

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Orientational Disorder In Sodium Cadmium Trifluoride Trihydrate, Nacdf3·3h2o, Robert W. Smith, Arthur Mar, Jianjun Liu, Stan Schnell, John R. Hardy Mar 2006

Orientational Disorder In Sodium Cadmium Trifluoride Trihydrate, Nacdf3·3h2o, Robert W. Smith, Arthur Mar, Jianjun Liu, Stan Schnell, John R. Hardy

Chemistry Faculty Publications

Attempts to synthesize the hypothetical anhydrous fluoroperovskite NaCdF3, which has been predicted to be stable, resulted instead in a hydrated fluoride of nominal composition NaCdF3·3H2O. It decomposes to sodium fluoride, cadmium fluoride, and water at 60 °C. Its structure has been determined by single-crystal X-ray diffraction. Na0.92(2)Cd1.08F3.08·2.92H2O crystallizes in the cubic space group with a = 8.2369(4) Å and Z = 4. The structure is based on the NaSbF6-type (an ordered variant of the ReO3-type) and features tilted sodium- and cadmium-centred octahedra …

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1,3-Indane-Based Chromogenic Calixpyrroles With Push-Pull Chromophores: Synthesis And Anion Sensing, Ryuhei Nishiyabu, Pavel Anzenbacher Jr. Feb 2006

1,3-Indane-Based Chromogenic Calixpyrroles With Push-Pull Chromophores: Synthesis And Anion Sensing, Ryuhei Nishiyabu, Pavel Anzenbacher Jr.

Chemistry Faculty Publications

Knoevenagel condensation of 2-formyl-octamethylcalix[4]pyrrole with selected 1,3-indanedione derivatives yields calix[4]pyrrole anion sensors with push-pull chromophores displaying strong intramolecular charge transfer. The push-pull feature results in augmented signal output as well as in dramatic changes in anion selectivity exemplified by a 50-fold increase in acetate vs chloride selectivity compared to the parent calix[4]pyrrole.

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Annealing Effects On The Crystallite Size And Dielectric Properties Of Ultrafine Ba1-Xsrxtio3 (0 < X < 1) Powders Synthesized Through An Oxalate-Complex Precursor, Gabriel Caruntu, Charles J. O'Connor Feb 2006

Annealing Effects On The Crystallite Size And Dielectric Properties Of Ultrafine Ba1-Xsrxtio3 (0 < X < 1) Powders Synthesized Through An Oxalate-Complex Precursor, Gabriel Caruntu, Charles J. O'Connor

Chemistry Faculty Publications

Nanocrystalline Ba12xSrxTiO3 (0 , x , 1) nanopowders were prepared through the oxalate route and the influence of the thermal history on their dielectric properties was investigated. For pelletized samples obtained by decomposing the corresponding oxalate intermediates at 600 uC and then annealed at different temperatures ranging from 600 to 1000 uC the dielectric constant decreases upon increasing the strontium content of the samples. Similar behavior was observed with decreasing the temperature of the thermal treatment of the pellets, a trend which is presumably ascribed to a synergic effect of decreasing the porosity of the samples, the increase of the …

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Spectroscopic Characterization Of The Ground And Low-Lying Electronic States Of Ga2n Via Anion Photoelectron Spectroscopy., S M. Sheehan, Giovanni Meloni, B F. Parsons, N Wehres, D M. Neumark Jan 2006

Spectroscopic Characterization Of The Ground And Low-Lying Electronic States Of Ga2n Via Anion Photoelectron Spectroscopy., S M. Sheehan, Giovanni Meloni, B F. Parsons, N Wehres, D M. Neumark

Chemistry Faculty Publications

Anion photoelectron spectra of Ga2N− were measured at photodetachment wavelengths of 416nm(2.978eV), 355nm(3.493eV), and 266nm(4.661eV). Both field-free time-of-flight and velocity-map imaging methods were used to collect the data. The field-free time-of-flight data provided better resolution of the features, while the velocity-map-imaging data provided more accurate anisotropy parameters for the peaks. Transitions from the ground electronic state of the anion to two electronic states of the neutral were observed and analyzed with the aid of electronic structure calculations and Franck-Condon simulations. The ground-state band was assigned to a transition between linear ground states of Ga2N−(XΣg+1) and Ga2N(XΣu+2), yielding the electron affinity …

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Structural And Evolutionary Classification Of G/U Wobble Basepairs In The Ribosome, Neocles B. Leontis, Ali Mokdad, Maryna V. Krasovska, Jiří Sponer Jan 2006

Structural And Evolutionary Classification Of G/U Wobble Basepairs In The Ribosome, Neocles B. Leontis, Ali Mokdad, Maryna V. Krasovska, Jiří Sponer

Chemistry Faculty Publications

We present a comprehensive structural, evolutionary and molecular dynamics (MD) study of the G/U wobble basepairs in the ribosome based on high-resolution crystal structures, including the recent Escherichia coli structure. These basepairs are classified according to their tertiary interactions, and sequence conservation at their positions is determined. G/U basepairs participating in tertiary interactions are more conserved than those lacking any interactions. Specific interactions occurring in the G/U shallow groove pocket-like packing interactions (P-interactions) and some phosphate backbone interactions (phosphate-in-pocket interactions)-lead to higher G/U conservation than others. Two salient cases of unique phylogenetic compensation are discovered. First, a P-interaction is conserved …

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Fluorescent Analysis Of Translesion Dna Synthesis By Using A Novel, Non-Natural Nucleotide Analogue, Irene Lee, Anthony J. Berdis Jan 2006

Fluorescent Analysis Of Translesion Dna Synthesis By Using A Novel, Non-Natural Nucleotide Analogue, Irene Lee, Anthony J. Berdis

Chemistry Faculty Publications

The replication of damaged DNA is a promutagenic process that can lead to disease development. This report evaluates the dynamics of nucleotide incorporation opposite an abasic site, a commonly formed DNA lesion, by using two fluorescent nucleotide analogues, 2-aminopurine deoxyribose triphosphate (2-APTP) and 5-phenylindole deoxyribose triphosphate (5-PhITP). In both cases, the kinetics of incorporation were compared by using a 32 P-radiolabel extension assay versus a fluorescence-quenching assay. Although 2-APTP is efficiently incorporated opposite a templating nucleobase (thymine), the kinetics for incorporation opposite an abasic site are significantly slower. The lower catalytic efficiency hinders its use as a probe to study …

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Recent Developments Inthe Mechanistic Enzymology Of The Atp-Dependent Lon Protease From Escherichia Coli: Highlights From Kinetic Studies, Irene Lee, Anthony J. Berdis, Carolyn K. Suzuki Jan 2006

Recent Developments Inthe Mechanistic Enzymology Of The Atp-Dependent Lon Protease From Escherichia Coli: Highlights From Kinetic Studies, Irene Lee, Anthony J. Berdis, Carolyn K. Suzuki

Chemistry Faculty Publications

Lon protease, also known as protease La, is one of the simplest ATP-dependent proteases that plays vital roles in maintaining cellular functions by selectively eliminating misfolded, damaged and certain short-lived regulatory proteins. Although Lon is a homo-oligomer, each subunit of Lon contains both an ATPase and a protease active site. This relatively simple architecture compared to other hetero-oligomeric ATP-dependent proteases such as the proteasome makes Lon a useful paradigm for studying the mechanism of ATP-dependent proteolysis. In this article, we survey some recent developments in the mechanistic characterization of Lon with an emphasis on the utilization of pre-steady-state enzyme kinetic …

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Controlling Rna Self-Assembly To Form Filaments, Neocles B. Leontis, Lorena Nasalean, Stéphanie Baudrey, Luc Jaeger Jan 2006

Controlling Rna Self-Assembly To Form Filaments, Neocles B. Leontis, Lorena Nasalean, Stéphanie Baudrey, Luc Jaeger

Chemistry Faculty Publications

Fundamental control over supra-molecular self-assembly for organization of matter on the nano-scale is a major objective of nanoscience and nanotechnology. 'RNA tectonics' is the design of modular RNA units, called tectoRNAs, that can be programmed to self-assemble into novel nano- and meso-scopic architectures of desired size and shape. We report the three-dimensional design of tectoRNAs incorporating modular 4-way junction (4WJ) motifs, hairpin loops and their cognate loop-receptors to create extended, programmable interaction interfaces. Specific and directional RNA-RNA interactions at these interfaces enable conformational, topological and orientational control of tectoRNA self-assembly. The interacting motifs are precisely positioned within the helical arms …

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Cacu3ti4o12: Low-Temperature Synthesis By Pyrolysis Of An Organic Solution, Jianjun Liu, Yucheng Sui, Chun-Gang Duan, Wai-Ning Mei, Robert W. Smith, John R. Hardy Jan 2006

Cacu3ti4o12: Low-Temperature Synthesis By Pyrolysis Of An Organic Solution, Jianjun Liu, Yucheng Sui, Chun-Gang Duan, Wai-Ning Mei, Robert W. Smith, John R. Hardy

Chemistry Faculty Publications

The giant-dielectric-constant material CaCu3Ti4O12 (CCTO) has been synthesized by pyrolyzing an organic solution containing stoichiometric amounts of the metal cations, which is done at lower temperature and shorter reaction time than the conventional solid-state reaction. A stable solution was prepared by dissolving calcium nitrate, copper(II) nitrate, and titanium(IV) isopropoxide in 2-methoxyethanol. This solution was pyrolyzed and heat-treated to achieve single-phase CCTO. The phases, microstructures, and dielectric properties of intermediate and final samples were characterized by X-ray diffraction, scanning electron microscopy, and dielectric spectroscopy.

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Preparation Of Some Substituted Terephthalic Acids, Susanna Branion, Vladimir Benin Jan 2006

Preparation Of Some Substituted Terephthalic Acids, Susanna Branion, Vladimir Benin

Chemistry Faculty Publications

We report in detail the preparation of two substituted terephthalic acids: 2‐sulfomethylterephthalic acid (1) and 2‐phosphonoterephthalic acid (2). Efficient, short syntheses have been developed for both compounds. They are potentially useful monomers for construction of acid‐pendant polymer chains.

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Preparation, Characterization And Dft Studies Of Some New N-Nitrosocarbamates And N-Nitrosoureas, Ragavan Narayanan, Helene Hedian, Eric Shamo, Vladimir Benin Jan 2006

Preparation, Characterization And Dft Studies Of Some New N-Nitrosocarbamates And N-Nitrosoureas, Ragavan Narayanan, Helene Hedian, Eric Shamo, Vladimir Benin

Chemistry Faculty Publications

We are presenting the preparation, characterization and density functional theory (DFT) studies {B3LYP/6-31+G(d)) of several reiated classes of N-nitrosocarbamates and N-nitrosoureas. The iong-range goal is the design and preparation of compounds, which would undergo photochemical or hydrolytic decomposition, to yield stabilized cyclic cations that can serve as alkylating agents at various nucleophilic centers, including DNA bases.

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(E)-9,10-Dihydro-9-Methyl-9-Nitro-10-(Trinitro­Meth­Yl)Anthracene, Mustafa Arslan, Ronald J. Baker, John Masnovi, Erol Asker Dec 2005

(E)-9,10-Dihydro-9-Methyl-9-Nitro-10-(Trinitro­Meth­Yl)Anthracene, Mustafa Arslan, Ronald J. Baker, John Masnovi, Erol Asker

Chemistry Faculty Publications

The title compound, C16H12N4O8, was prepared by the photochemical reaction of 9-methyl­anthracene and tetra­nitro­methane in dichloromethane. Intermolecula face-to-face π–π stacking inter­actions are present along the a axis.

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Lead Optimization Of 7-Benzyloxy 2-(4′-Pyridylmethyl)Thio Isoflavone Aromatase Inhibitors, Bin Su, John C. Hackett, Edgar S. Diaz-Cruz, Young Woo Kim, Robert W. Brueggemeier Dec 2005

Lead Optimization Of 7-Benzyloxy 2-(4′-Pyridylmethyl)Thio Isoflavone Aromatase Inhibitors, Bin Su, John C. Hackett, Edgar S. Diaz-Cruz, Young Woo Kim, Robert W. Brueggemeier

Chemistry Faculty Publications

Aromatase, the enzyme responsible for estrogen biosynthesis, is a particularly attractive target in the treatment of hormone-dependent breast cancer. The synthesis and biological evaluation of a series of 2-(4′-pyridylmethyl)thio, 7-alkyl- or aryl-substituted isoflavones as potential aromatase inhibitors are described. The isoflavone derivatives demonstrate IC50 values from 79 to 553 nM and compete with the endogenous substrate, androstenedione. Data supporting the ability of these analogs to suppress aromatase enzyme activity in the SK-BR-3 breast cancer cell line are also presented.

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Covalently Networked Monolayer Protected Nanoparticle Films, D. J. Tognarelli, Robert B. Miller, Rebecca R. Pompano, Andrew F. Loftus, Daniel J. Shiebley, Michael C. Leopold Oct 2005

Covalently Networked Monolayer Protected Nanoparticle Films, D. J. Tognarelli, Robert B. Miller, Rebecca R. Pompano, Andrew F. Loftus, Daniel J. Shiebley, Michael C. Leopold

Chemistry Faculty Publications

No abstract provided.

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Interaction Of Porphyrins With A Dendrimer Template: Self-Aggregation Controlled By Ph, Pavel Kubat, Kamil Lang, Pavel Janda, Pavel Anzenbacher Jr. Oct 2005

Interaction Of Porphyrins With A Dendrimer Template: Self-Aggregation Controlled By Ph, Pavel Kubat, Kamil Lang, Pavel Janda, Pavel Anzenbacher Jr.

Chemistry Faculty Publications

The interaction between self-aggregated porphyrins such as 5,10,15,20-tetrakis(4-sulfonatophenyl)porphyrin (TPPS) and 5,10,15,20-tetrakis(4-phosphonatophenyl)porphyrin (TPPP), and a generation 5 (G5) PAMAM dendrimer template is governed by minute differences of porphyrin acido-basic properties. While at neutral pH both monomeric TPPS and TPPP form complexes with G5, decreasing pH did not lead to porphyrin ring protonation (pK(a) approximate to 5) but rather to the preferential formation of H-aggregates (probably H-dimers), most likely due to protonation of the G5. Upon further acidification of the solution, this face-to-face orientation of the porphyrin units is being converted to edge-to-edge aligned J-aggregates with a tightly defined structure. This process …

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Simple Electrooptical Sensors For Inorganic Anions, Pavel Anzenbacher Jr., Karolina Jursikova, Manuel Marquez Oct 2005

Simple Electrooptical Sensors For Inorganic Anions, Pavel Anzenbacher Jr., Karolina Jursikova, Manuel Marquez

Chemistry Faculty Publications

Electrooptical sensors consisting of a conjugated chromophore undergoing a change in color and a redox-active moiety such as quinone fused to the chromophore were synthesized. Strong changes in colorimetric and electrochemical properties were observed in the presence of inorganic anions. A unique anion-specific response was observed for fluoride, pyrophosphate, and acetate. DFT (B3LYP/6-31G*) calculations performed for both "on/off" states of a sensor-fluoride model are in good agreement with the observed electrochemical and spectroscopic data.

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Benzothiadiazoles And Dipyrrolyl Quinoxalines With Extended Conjugated Chromophores−Fluorophores And Anion Sensors, Dmitry Aldakov, Manuel A. Palacios, Pavel Anzenbacher Jr. Oct 2005

Benzothiadiazoles And Dipyrrolyl Quinoxalines With Extended Conjugated Chromophores−Fluorophores And Anion Sensors, Dmitry Aldakov, Manuel A. Palacios, Pavel Anzenbacher Jr.

Chemistry Faculty Publications

Stable fluorescent chromophores find use in a growing number of practical applications, including their utility as laser dyes,1 emitters in light-emitting diodes,2 photoconductors,3 optical data storage,4 and optical switches.5 Stable fluorophores with high quantum yields are widely used in fluorescent sensors6 and labels.7 These became very popular lately, owing to their potential for high sensitivity at low concentration coupled with decreased cost of the required equipment.8 Recently, we have described a new class of fluorescent anion sensors bearing extended conjugated chromophores9 with incorporated 2,3-di(1H-2-pyrrolyl)quinoxaline, (DPQ), as the anion recognition element.10 Literature shows that DPQ binds anions via hydrogen bonding between …

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1,3-Bis(9-Ethyl­Carbazol-3-Yl)Propane, Erol Asker, John Masnovi Sep 2005

1,3-Bis(9-Ethyl­Carbazol-3-Yl)Propane, Erol Asker, John Masnovi

Chemistry Faculty Publications

In the title compund, C31H30N2, π–π overlap is absent in the region where carbazole groups of two adjacent mol­ecules are inclined toward each other. The eth­yl groups which protrude from the plane of the carbazole groups and the alkyl­ene chain connecting the two carbazole groups are responsible for the poor mol­ecular stacking.

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Incorporation Of Factor Va Into Prothrombinase Is Required For Coordinated Cleavage Of Prothrombin By Factor Xa, Michael A. Bukys, Melissa A. Blum, Paul Y. Kim, Nicole Brufatto, Michael E. Nesheim, Michael Kalafatis Jul 2005

Incorporation Of Factor Va Into Prothrombinase Is Required For Coordinated Cleavage Of Prothrombin By Factor Xa, Michael A. Bukys, Melissa A. Blum, Paul Y. Kim, Nicole Brufatto, Michael E. Nesheim, Michael Kalafatis

Chemistry Faculty Publications

Prothrombin is activated to thrombin by two sequential factor Xa-catalyzed cleavages, at Arg271 followed by cleavage at Arg320. Factor Va, along with phospholipid and Ca2+, enhances the rate of the process by 300,000-fold, reverses the order of cleavages, and directs the process through the meizothrombin pathway, characterized by initial cleavage at Arg320. Previous work indicated reduced rates of prothrombin activation with recombinant mutant factor Va defective in factor Xa binding (E323F/Y324F and E330M/V331I, designated factor VaFF/MI). The present studies were undertaken to determine whether loss of activity can be attributed to selective loss of efficiency at one or both of …

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Synthesis And Characterization Of Azole Isoflavone Inhibitors Of Aromatase, John C. Hackett, Young Woo Kim, Bin Su, Robert W. Brueggemeier Jun 2005

Synthesis And Characterization Of Azole Isoflavone Inhibitors Of Aromatase, John C. Hackett, Young Woo Kim, Bin Su, Robert W. Brueggemeier

Chemistry Faculty Publications

The synthesis and biological evaluation of a series of 2-azole and 2-thioazole isoflavones as potential aromatase inhibitors are described. Differences in inhibitory activity of triazole and imidazole inhibitors are rationalized with density functional theory to expose a key difference in the electronic structure of these molecules. In addition, difference binding spectra of inhibitors to immunoaffinity-purified aromatase produces classical Type II spectra consistent with coordination of the nitrogen lone pair electrons to the aromatase P450 heme.

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