bluuebunny/crossref_metadata_2025 huggingface dataset:
Determination of Naphthalenesulfonate Isomers in Industrial Effluents and River Water by Solid‐Phase Extraction and Capillary Zone Electrophoresis
Authors: Liu Cm‐Hung , Ding Wang‐Hsien
Published: May 2015

This work presents a method to separate polar naphthalenesulfonate (NS) isomers by capillary zone electrophoresis (CZE) with ultraviolet detection in industrial effluents and river water samples. The method involves extraction of samples by a polystyrene‐divinylbenzene copolymer (PS‐DVB) solid‐phase extraction (SPE) cartridge. The most effective CZE separation conditions were obtained in 20 mM borate buffer with 30% acetonitrile at pH 9.0 and 30 °C. The method proposed herein provides a high precision and sensitivity for NS isomers, to quantitation at ≤ 1.0 μg/L in 200 mL of the water samples. Recovery of the NS isomers in spiked water samples ranged from 73% to 87% while RSD ranging from 5.6 to 9.7%. The analysis of industrial effluents and river water samples was performed and naphthalene‐2‐sulfonate was found as a major pollutant. The difficulties in quantitating and identifying analytes in complex environmental samples can be resolved by using an internal standard response factor to calculate concentrations and relative migration times for peak confirmation.
Pictet‐Spengler Condensation of N,N‐Dimethylsulfamoyl‐β‐Phenethylamines with Methylthioacetic Acid Ethyl Ester. New Synthesis of Ethyl 1,2,3,4‐Tetrahydroisoquinoline‐1‐Carboxylates
Authors: Wang Huey‐Min , Su Chien‐Hsing , Kang Iou‐Jmn , Chen Lmg‐Chmg
Published: May 2015

The reaction of N,N‐dimethylsulfamoyl‐β‐phenethylamines with methylthioacetic acid ethyl ester using phenyliodine(III) bis(trifluoroacetate) gives moderate to good yields of the corresponding ethyl 1,2,3,4‐tetrahydroisoquinoline‐1‐carboxylates.
Photocatalytic Acetolysis of α‐Epoxyketones
Authors: Memarian Hamid R. , Nikpour Farzad
Published: May 2015

Photocatalytic ring opening of α‐epoxyketones by 2,4,6‐triphenylpyrylium tetrafluoroborate in glacial acetic acid resulted in the formation of diastereomeric hydroxyester compounds. The presence of the additional substitutent on the parent molecule affects the rate of the ring opening.
A New Redox Reaction of Ascorbic Acid at Platinum Electrodes
Authors: Ye Bao‐Xian , Lin Lin , Wang Cm‐Hong , Jin Bao‐Hm , Liu Ling‐Fang
Published: May 2015

A pair of new redox peaks of ascorbic acid at a platinum electrode was found and studied in detailed by spectroelectrochemistry and electrochemistry technologies. This is a quasi‐reversible redox reaction with a one‐electron transfer process. The intermediate of tertiary carbon free radical exists in this process. The appearance reaction rate constant and the diffusion coefficient were investigated. A possible reaction mechanism has been proposed.
Amyloid Structure: Models and Theoretical Considerations in Fibrous Aggregates
Authors: Morgan David M. , Lynn David G. , Lakdawala Ami S. , Snyder James P. , Liotta Dennis C.
Published: May 2015

In celebration of the many contributions to peptide chemistry from K.‐T. Wang's laboratory, this manuscript explores the structure of the Aβ(10–35) fibril. This central segment of the Aβ peptide of Alzheimer's Disease self‐assembles into well‐ordered paracrystalline arrays that seem to contradict many of the accepted paradigms established for soluble, globular proteins. Here we exploit initial molecular modeling efforts to assist in understanding these apparent contradictions. The emerging structure is one of a large self‐assembly of β‐strands, whose stability is dependent on large spatial and temporal fluctuation about a central core, giving rise to what can be best described as a dynamic and fluid tube‐like micelle. This fibril structure maintains features that are distinctly different from those of either synthetic or biological fibrils, and these differences have profound implications for biomedical intervention in amyloid diseases as well as for the design of self‐assembling nanoscale fibrils.
Lithium Hydrides and Lithium Dimers: Sub‐Doppler Spectroscopy and Dynamics
Authors: Bouloufa N. , Cacciani P. , Jeung G.‐H. , Vetter R.
Published: May 2015

Deep insights into molecular structures and dynamics were obtained for lithium dimers and lithium hydrides by sub‐Doppler spectroscopy combining molecular beams and cw tunable laser beams. For 7Li7Li species, accurate spectroscopic studies of the B 1Πu‐X 1Σg+ system were carried out, with the measurement of hundreds of wave numbers and with the determination of dissociation rates due to tunneling through the potential barrier of the B 1πu state. They led to the full description of the B state potential, including its barrier. For 6Li7Li species, weak but non‐negligible dissociation rates in the B 1Πu state were observed, measured and interpreted assuming that an electronic coupling between the B 1Πu and 1 1Πg states takes place through an ungerade‐gerade symmetry breaking. For LiH species, the A 1Σ+‐X 1 Σ+ system was revisited for both isotopomers. For this molecule, dynamical effects are predicted in highly‐excited Rydberg states, that could be studied by use of similar sub‐Doppler techniques.
Formation of Alkyne Bridged Multicobalt Carbonyl Complexes with Tris(2‐Thienyl)Phosphine or Bis(Trimethylsilylethynyl)Phenylphosphine Ligand
Authors: Hong Fung‐E , Lien Fang‐Ching , Chang Yu‐Chang , Ko Bao‐Tsan
Published: May 2015

Treatment of Co4(CO)12 with an excess of trimethylsilylacetylene (TMSA) in the presence of tri(2‐thienyl)phosphine in THF at 25 °C for 2 hours yielded six compounds. Two pseudo‐octahedral, alkyne‐bridged tetracobalt clusters, [Co4(μ4‐η2‐HC≡CSiMe3)(CO)10(μ‐CO)2] (4) and [Co4(μ4‐η2‐HC≡CSiMe3)‐(CO)9(μ‐CO)2{P(C4H4S)3}] (6), along with an alkyne‐bridged dicobalt complex, [Co2(CO)5(μ‐HC≡CSiMe3)‐{P(C4H4S)3}] (5), were obtained as new compounds. The addition of the thienylphosphine ligand, in fact, facilitates the reaction rate.

Reaction of an alkyne‐bridged dicobalt complex, [(η2‐H‐C≡C‐SiMe3)Co2(CO)6] (3), with a bi‐functional ligand, PPh(‐C≡C‐SiMe3)2, yielded an unexpected six‐membered, cyclic compound, {(Ph)(Me3Si‐C≡C)P‐[(η2‐C≡C‐SiMe3)Co2(CO)5]}2 (7).

All of these new compounds were characterized by spectroscopic means; the solid‐state structures of (5), (6) and (7) have been established by X‐ray crystallography.
Analysis of Petroleum Distillates from Fire Debris Using Supercritical Fluid Extraction with a Two‐Level Orthogonal Array Experimental Design
Authors: Huang Ching‐Te , Hsieh You‐Zung
Published: May 2015

A supercritical fluid extraction (SFE) method was developed in the present study as an effective sample pretreatment technique of petroleum distillates from fire debris. Three petroleum distillates were used as target analytes, including 95 unleaded gasoline, kerosene, and premium diesel. An orthogonal array (L16) experimental design was adopted to separately evaluate primary SFE experimental factors. The SFE efficiencies of petroleum distillates at various extraction conditions were examined and the optimized SFE conditions were identified. Experimental results demonstrated that the optimized SFE method not only provided an effective extraction method for the spiked sample, but also successfully recovered residues of petroleum distillates from fire debris.
Solubilization and Separation of Dicarboxylic Acids by Surfactant Micelles and Polyelectrolytes
Authors: Mahmoud Faten Z. , Youssef Mona I.
Published: May 2015

Semi‐equilibrium dialysis (SED) and micellar enhanced ultra filtration (MEUF) methods are used to determine the extent of solubilization of water‐insoluble compounds by surfactant and polyelectrolyte. In this study, solubilization of ortho‐, meta‐ and para‐phthalic acids (OPA, MPA and TPA), 1,4‐ and 2,6‐naphthalene dicarboxylic acids (1,4‐NDCA and 2,6‐NDCA) into hexadecylpyridinium chloride (CPC), and the behavior of these acids to bind to the polyelectrolyte ionizable groups were investigated at 25 °C, using SED and MEUF methods. Polydimethyldiallylammonium chloride (PDMDAAC) is used in this study.

It was found that the solubilization of organic acids decreases with increasing the solute mole fractions in micelles. Also, the best separation occurs at the lowest concentration of the phthalate ions and high concentrations of either CPC or PDMDAAC. The results support the idea of charge interaction between the anionic dicarboxylate groups and cationic surfactant or polyelectrolyte. The results also show that the presence of a second phenyl ring does not greatly affect the solubilization behavior of the acids.
Synthesis and Visible Spectral Behaviour of Some New N‐Bridgehead Heterocyclic Cyanine Dyes Incorporating Pyrazolo (4,5‐b) Indolizine (Benzoindolizine)
Authors: Koraiem A. I. M. , El‐Aal R. M. Abd , Mohammed N. S.
Published: May 2015

The new unsymmetrical N‐bridgehead, apo (zeromethine), mono‐methine, dimethine, meso substituted tetramethine and styryl cyanine dyes incorporating pyrazolo (4,5‐b) indolizine (benzoindolizine) nuclei were prepared. Structural confirmation was carried out by elemental analyses, IR, H‐NMR, mass spectra and 13C‐NMR with the aid of carbon DEPT spectral data. The visible absorption spectra for the newly synthesized cyanines were examined in 95% ethanol.
Bovine Serum Albumin as the Additive of Chiral Mobile Phase for Enantiometric Separation of Dansyl‐Amino Acids with Size‐Exclusion Chromatography
Authors: Liu Fu‐Ken , Wei Guor‐Tzo
Published: May 2015

This work used bovine serum albumin (BSA) as a chiral selector in the mobile phase additive of Size‐exclusion Chromatography (SEC) for enantiomeric separation of Dansyl‐derivative amino acids and the measurement of dissociation constant between Dansyl‐derivative amino acids and BSA. The parameters, such as BSA concentration and buffer concentration, were investigated to obtain the optimized enantiomeric resolution conditions. Also, theoretical descriptions of those parameters' effect on the separation are presented to correlate with experimental results. Baseline resolution of Dansyl‐norvaline, which was used as a model molecule, was obtained with the optimized condition of 80 ppm BSA, 8 mM phosphate at pH 7.4, and 25 °C column temperature. This optimized condition was employed to separate other amino acids. The separation results were then applied to calculate the dissociation constant between the guest molecular (Dansyl‐derivative amino acids) and the host molecular (BSA). The results show that the SEC system can be easily employed for both enantiomeric separation of Dansyl‐amino acids and the measurement of dissociation constants between Dansyl‐amino acids and serum protein.
Single Molecule Fluorescence Spectroscopy
Authors: White J. D. , Hsu J. H. , Wang C. F. , Chen Y. C. , Hsiang J. C. , Su S. C. , Sun W. Y. , Fann W. S.
Published: May 2015

Single molecule spectroscopy can uncover fluctuation averaged out in ensemble measurements. In addition, single molecule spectroscopy naturally implies ultra‐sensitive measurements, which should play important role in future proteomics and genomic research. Fluorescence method is the most commonly used single molecule detection. In this paper, we will use single conjugated polymer fluorescence spectroscopy to illustrate the power of this technique.
Generalized Floquet Formulation of Time‐Dependent Density Functional Theory for Multiphoton Processes in Intense Laser Fields
Authors: Chu Shih‐I , Telnov Dmitry A.
Published: May 2015

We present a short review article of recent new developments of Floquet formulations of time‐dependent density functional theory (TDDFT) for ab initio nonperturbative treatment of multiphoton and high‐order nonlinear optical processes of many‐electron quantum systems in intense laser fields. In the presence of monochromatic or polychromatic (multi‐color) time‐dependent fields, it is shown that the time‐dependent Kohn‐Sham equation can be exactly reformulated as a time‐independent generalized Floquet matrix eigenvalue problem. The theory has been extended to include the time‐dependent current density functional theory (TDCDFT) as well. In the case of bound‐free transition processes such as multiphoton ionization or dissociation, we show that the complex scaling transformation can be implemented into the Floquet formulation of TDDFT and TDCDFT, and the field‐induced complex quasienergy (dressed) states of many‐electron quantum systems can be determined by means of the solution of a time‐independent non‐Hermitian Floquet matrix eigenvalue problem. To facilitate the exploration of the constraints satisfied by the universal but unknown time‐dependent exchange‐correlation energy functionals, we develop several exact relations and theorems for the quasienergy functionals. Finally we present some initial applications of the Floquet‐TDDFT formalism for the study of multiphoton ionization of neutral atoms and electron angular distribution in multiphoton detachment of negative ions in intense laser fields. The Floquet‐TDDFT/TDCDFT formalism provides a powerful new theoretical foundation and feasible procedures for the exploration of many‐electron atomic and molecular physics in strong fields in the future.
Characterization of Sodiated Lipids by Electrospray Ionization‐Quadrupole Ion Trap Tandem Mass Spectrometry
Authors: Ho Yen‐Peng , Huang Ping‐Chen
Published: May 2015

Collisionally activated dissociation (CAD) of glycerophosphoglycerol, glycerophosphocholine, glycerophosphoethanolamine, and glycerophosphoserine species was examined using quadrupole ion trap mass spectrometry (QITMS). Since the spectral patterns obtained by QITMS may differ from those obtained using sector or quadrupole mass spectrometry, methods employed in the structure analysis of phospholipids on a sector or quadrupole mass spectrometer are not necessarily useful on an ion trap mass spectrometer. CAD (or MS/MS) of sodiated phospholipids was proposed to structurally analyze phospholipids. The CAD spectra of such ions obtained by QITMS revealed informative ions. Product ions that corresponded to the loss of polar heads identified the lipid classes. Product ions formed by the loss of fatty acyl substituents from sn‐1 and sn‐2 positions were also observed. A preferential loss of the sn‐1 fatty acyl group over the loss of the sn‐2 fatty acyl group was observed among the phospholipid standards examined. This facilitated the determination of the identities and positions of fatty acyl substituents.
The Early Stage of a β‐Hairpin Folding: The Role of Water Molecules
Authors: Li Feng‐Yin , Chen Turning , You Zhi‐Qiang , Mou Chung‐Yuan
Published: May 2015

Water has been shown to play a crucial role in stability and catalytical function. Our purpose is to understand the salvation behavior of water molecules during the folding process, in particular, a deca‐peptide β‐hairpin folding. We performed molecular dynamics simulation by employing AMBER6.0 with an explicit water model. The results indicate that water molecules surrounding a biomolecule can be categorized into at least three shells.
Structures and UV‐Visible Absorption Properties of Unsymmetrical Bisdithiolene Nickel Complexes
Authors: Wang Chih‐Chieh , Wu Wei‐Ching , Lee Gene‐Hsiang , Chen Chin‐Ti
Published: May 2015

A new unsymmetrical bisdithiolene nickel complex Ni(Et2dazdt)(mnt) was synthesized and structurally characterized, where Et2dazdt and mnt denote 1,4‐diethyl‐perhydrodiazepine‐2,3‐dithione and maleonitrildithiolate, respectively. Its crystal structure and absorption spectrum were determined and compared to those of Ni(Et2pipdt)(mnt), where Et2pipdt is 1,4‐diethyl‐piperazine‐2,3‐dithione. X‐ray diffraction analysis reveals that the Ni(S2C2)2 moiety of Ni(Et2dazdt)(mnt) is not planar due to the twist conformation of a seven‐member ring of Et2dazdt ligand. The twisting of Et2pipdt is less severe and NiS4 center of Ni(Et2pipdt)(mnt) possesses a closer to planar conformation than that of Ni(Et2dazdt)(mnt). Unlike Ni(Et2pipdt)(mnt), Ni(dazdt)(mnt) shows two major separated absorption bands in the visible and near‐IR region, although both absorption bands show negative solvatochromism similar to that of Ni(Et2pipdt)(mnt).
Nonlinear Light Absorption in Porphyrin Derivatives Including the Complexes of the IIIa Metal Group
Authors: Wen T. C. , Hwang L. C. , Lin W. Y.
Published: May 2015

The nonlinear absorption properties of GaClTMPP, InClTMPP and TlClTMPP (TMPP: tetrakis‐(3,4,5‐trimethoxyphenyl)porphyrins) doped in boric acid glass are probed using the Z‐scan technique at different wavelengths. The characteristc of reverse saturable absorption (RSA) is observed at 532 nm, while the two photon absorption (TPA) is dominated at several wavelengths from 840 to 1350 nm. We find that the excited state absorption cross section σex at 532 nm is enlarged along a series of the central metal ions: Ga(III)Cl < In(III)Cl < Tl(III)Cl, and the two‐photon allowed transitions at near infrared are proposed to be 1B*1g ← S0 and 1B*2g ← S0
Influence of Alkanethiols Adsorption on Oxidized Copper Nanoparticles
Authors: Chen Shin‐Fu , Yeh Chen‐Sheng
Published: May 2015

Alkanethiols were introduced to study their influence on the oxidized Cu colloids. The XPS measurements have been performed to characterize Cu identities in various stages, i.e. freshly prepared Cu, aged Cu, and aged Cu mixing with alkanethiols. The aged colloidal solutions resulted in CuO growth. The adsorption of alkanethiols on the oxidized copper reduced Cu2+ to Cu1+ with the formation of surface thiolates. Based on the TEM images, addition of alkanethiols yielded a distinct change in the colloidal appearance from aggregation to dispersion.
Optimum Synthesis of Mesoporous Silica Materials from Acidic Condition
Authors: Lin Hong‐Ping , Kuo Chin‐Lung , Wan Ben‐Zu , Mou Chung‐Yuan
Published: May 2015

On the basis of the mixtures composed of CnTMAB/acids/TEOS/water, the mesoporous materials with well‐ordered hexagonal structures can be synthesized under acidic condition (pH < 1.0) with a careful control of the silica condensation. However, the induction period time for the formation of surfactant‐silica precipitation varied with the employed acid source and decreased in the series: HNO3 < HBr < HCl < H2SO4 at the same acid concentration. Increasing the acid concentration not only induced a fast precipitation rate, but also provoked more nuclei seeds formation and reduced the particle size of the mesoporous silica products. A proper aging time is also significant for getting the well‐ordered mesoporous materials via acid route, and a longer aging time would induce a gradual decomposition of the mesostructures. For morphology, in acid synthetic medium, various interesting shell‐like curved patterns on the surface of mesoporous silica particles were formed. The physical properties (such as d‐spacing, pore size, BET surface area and porosity) of the calcined mesoporous silica are almost not affected by the nature of the acid source, but the pore size of the mesoporous materials can be tailored by varying the chain length of the surfactant. Adding the proper amount of ammonia solution for adjusting the pH value between 8–10 can improve the hexagonal mesostructures order of the mesoporous materials while maintaining the original morphology.
Improved Flow Injection Analysis of H2O2 on Cinder/Prussian Blue‐Modified Electrodes by CTAB Micelles
Authors: Zen Jyh‐Myng , Chen Pei‐Yan , Kumar Annamalai Senthil
Published: May 2015

In the present work, a new strategy involving the addition of CTAB at its critical micelle concentration was developed to improve the electrochemical properties of the cinder/PB‐modified screen‐printed electrode (designated as cinder/PB‐SPE) in the detection of H2O2 by flow injection analysis (FIA). Such new PB hybrids derived from cinder have remarkable stability even under strong hydrodynamic stress. The cylindrical CTAB micelles formed at the 2nd critical micelle concentration can effectively promote the PB redox behavior. Under optimized conditions with pH 7 PBS + 7 mM CTAB as carrier solution in FIA, a linear calibration was obtained up to 25 μM H2O2 with slope, regression coefficient, and detection limit (S/N = 3) of 1.03 A/Mcm2, 0.995, and 4.02 μM respectively. Interferences by direct electrochemical oxidation of easily oxidizable substances can be prevented due to the low detecting potential of the working system.
Continuous On‐Line Monitoring of Trihalomethanes in Chlorinated Drinking Water Using an Automated System Based on Pulse Introduction Membrane Extraction and High Speed Gas Chromatography/Mass Spectrometry
Authors: Chang Cheng Chin , Lu Pei Fen , Her Guor Rong
Published: May 2015

An automated system based on pulse sample introduction membrane extraction and gas chromatography/mass spectrometry (GC/MS) has been developed for on‐line monitoring of Trihalomethanes (THMs) in chlorinated drinking water. Pulse samples were injected into the membrane through a sample loop. Zero air was used as the eluent to elute the water samples and also acted as the purging gas. The use of zero air as the purging gas facilitates the cleanup of the membrane to reduce the tailing part of sample input. Under typical operating conditions, the cycle time can be reduced to less than 4 min. The detection limits of this system were found to be about 50 ppt, 50 ppt, 50 ppt, and 20 ppt for CHCl3, CHBrCl2, CHBr2Cl, and CHBr3, respectively. The utility of this system was demonstrated with a ten‐hour on‐line monitoring of THMs in tap water.
Low‐Pressure One‐Step Synthesis of Methyl Isobutyl Ketone from Acetone and Hydrogen over Metal Modified Solid Base Catalysts
Authors: Lin Kai‐Hsim , Ko An‐Nan
Published: May 2015

One‐step synthesis of methyl isobutyl ketone (MIBK) from acetone and hydrogen over metal modified solid base catalysts has been studied at atmospheric pressure and 175–250 °C by using a fixed‐bed, integral‐flow reactor. Two types of catalysts have been utilized: (1) zeolites modified with palladium (Pd/Kβ, Pd/KZSM‐5); and (2) metal oxides modified with sodium and palladium (Pd/Na/MgO, Pd/Na/NaOH/γ‐Al2O3). The catalyst properties were characterized by the methods of atomic absorption, temperature‐programmed desorption and gas adsorption. Sodium vapor deposition on magnesia, followed by impregnation with tetraamine palladium (II) chloride apparently enhances the catalyst basicity as compared with that of magnesia supported palladium. For catalysts with different supports, the base amount decreases in the order of Pd/Na/MgO > Pd/Na/NaOH/γ‐Al2O3 > Pd/KZSM‐5 > Pd/Kβ, in accordance with the catalytic activities. As the amount of sodium or palladium in Pd/Na/MgO increases, the catalyst base amount, acetone conversion and MIBK selectivity are also enhanced to a maximum and then decline. Better catalytic results were attained at a higher pretreating temperature of hydrogen on the catalyst. The optimum conditions for this reaction are 0.5%Pd/0.47%Na/MgO pretreated with hydrogen at 400 °C, reaction temperature 200 °C, acetone/hydrogen mol ratio 1, and W/Fa 6g·h/mol. Under these conditions, the acetone conversion and MIBK yield are 47.3% and 30.7%, respectively, at 480 min time‐on‐stream. The reaction network and reaction mechanism for the formation of MIBK are proposed and discussed.
A New Simple and Accurate Turbidimetric Method for Determination of Ascorbic Acid in Pharmaceuticals and Fruits
Authors: Farajzadeh Mir Ali , Nagizadeh Sepideh
Published: May 2015

An accurate, simple, solvent free and inexpensive turbidimetric method is presented for the determination of ascorbic acid in pharmaceutical preparations and fruits. It needs no special reagents or precautions. In this method HgCl2 oxidizes ascorbic acid in citrate buffer at a pH of about 4 and produced Hg2Cl2 precipitate as monitored by turbidance measurements. The procedure is very simple and the experimental conditions such as temperature, ionic strength, stirring and time are not critical. High sensitivity and selectivity are two other advantages of this method. Linear dynamic range of the calibration curve is between 3–120 μg/mL with limit of detection (LOD) 1 μg/mL, which allows the ascorbic acid contents of most fruits and vegetables to be analyzed. On the other hand, the interference studies show that common compounds in real samples and colored substances have no considerable effect on the determination. Only filtration of some samples is necessary and other treatments, which are performed prior to determination of ascorbic acid by other analytical methods, are eliminated. Finally, ascorbic acid concentration in different samples is determined by the proposed method and obtained results are compared with the results of the official 2,6‐dichlorophenolindophenol or iodimetric methods and a good agreement is obtained. This method is very sensitive in comparison with iodimetry and is very fast relative to the 2,6‐dichlorophenolindophenol method.
Purification ofCandida RugosaLipase Using Agarose Mercurial Column
Authors: Tai Dar‐Fu , Chang Yuan‐Fimg , Chiou Tzyy‐Wen
Published: May 2015

Candida rugosalipase from Sigma was subjected to an agarose mercurial column, and the three fractions thus collected were further desalted using a Sephadex G‐25 column. The purification of these isozymes increases their catalytic activities toward the hydrolysis of triacetin. An improved resolution on the hydrolysis of 2‐chloroethyl 2‐phenylpropionate was also observed by utilizing one of the isolated isozymes CRL II.
Formation of ATP by Photochemical Excitation of Benzoquinones in Dimethylacetamide Solution
Authors: Lee Hung‐Wen , Huang Kunpo
Published: May 2015

A new method of adenosine triphosphate production is described which involves photo‐excitation of p‐benzoquinones under the presence of adenosine diphosphate and inorganic phosphate in N,N‐dimethylacetamide solution. A possible mechanism for the reaction is presented.
Substitution Coordination Approach for Selective Determination of Complex: Pontachrome Violet SW/Fe(III)/Cu(II) System
Authors: Gao Hong‐Wen , Hu Nai‐Liang
Published: May 2015

The Substitution Coordination for Selective Determination (SCSD) was proposed by studying the complexations of pontachrome violet SW (PCV) with Fe(III) and Cu(II) at pH 5.5. The up dated approach to the de termination of binding constants of a complex was established by the spectral correction technique (SCT). The substitution complexation Cu(II) + Fe(PCV) → Cu(PCV) + Fe(III) has been applied to the direct selective determination of copper traces by the SCT with a high sensitivity.
Four‐ and Five‐Coordinate Gallium Complexes Stabilized by Bidentate 2‐(Dimethylaminomethyl)Pyrrole Ligand: Molecular Structures of Ga[NC4H3(CH2NMe2)‐2]3and GaMe2[NC4H3(CH2NMe2)‐2]
Authors: Yu Ru‐Ching , Huang M‐Hsien , Lee Gene‐Hsiang , Peng Shie‐Ming
Published: May 2015

Treatment of GaCl3with one equiv of Li[NC4H3(CH2NMe2)‐2] (n = 1, 2, 3) in diethyl ether at −78 °C yields GaCl3‐n[NC4H3(CH2NMe2)‐2]n(n = 1,1; n = 2,2; n = 3,3). Compound 1 reacts with two equiv of RLi to afford GaR2[NC4H3(CH2NMe2)‐2] (4a, R=Me; 4b, R=Bu) via transmetallation. Reacting 2 with one equiv of RLi in diethyl ether,3and4are formed via ligand redistribution. Variable temperature1H NMR spectroscopic experiments reveal that the five‐coordinate gallium compound3is fluxional and results in a coalescence temperature at 5 °C, at which ΔG≠is calculated at ca. 10.4 Kcal/mole. All the new compounds have been characterized by1H and13C NMR spectroscopy and the structures of compounds3and4ahave also been determined by X‐ray crystallography.
Separation of Dyes from Aqueous Solutions by Paper Adsorption
Authors: Wang Wan‐Kung , Zhou Whe‐Zuang , Huang Whe‐Ling
Published: May 2015

Separation of the dyes methyl violet, methylene blue, and congo red from aqueous solutions by paper capillary permeation adsorption method was studied using paper. Nearly 100% of the investigated dyes could be separated under the optimum conditions. The effect of pH on the separation efficiency was studied in particular. At pH 5–9, 1.3–11, and 7–11, the maximum separation was achieved for methyl violet, methylene blue and congo red, respectively. The effects of dye concentration and some foreign ions on the separatability were examined. Moreover, the selective separation of some dyes was attempted by elution with chemical reagents.
Studies with Alkylheterocycles: Novel Synthesis of Functionally Substituted Isoquinoline and Pyridopyridines Derivatives
Authors: Elmaati Tarek M. Abu , El‐Taweel Fathy M. A.
Published: May 2015

Several isoquinolines were prepared via reacting pyridine 4 with cinnamonitriles 5a‐c or 5d‐f. Treating 4 with elemental sulphur yielded thienopyridine 9. 9 reacts with acrylonitrile to give isoquinoline 12. 12 was also prepared from 4 and methylenemalononitrile. Condensation of 4 with aromatic aldehydes gave the arylidine 13. 13 afforded the pyridine 14 and 15 on treating it with NH4OH and AcOH/HCl, respectively.
Systematical Synthesis of Distamycin Analogues and Their Interaction with Herring Sperm DNA
Authors: Tang Feili , Wang Jin , Liu Dan , Li Jingjian , Yuan Gu
Published: May 2015

A simple procedure for the systematical synthesis of eight distamycin analogues containing N‐methylpyrrole (Py) and N‐methylimidazole (Im) has been developed by a chloroform reaction and DCC coupling reaction without amino protection and deprotection, and the interaction of the analogues with Herring Sperm DNA was investigated by fluorescence spectroscopy.
Synthetic Study of 4‐Substituted Piperidine Ring in Elarofiban, RWJ‐50042, Tirofiban and Paroxetine
Authors: Chang Meng‐Yang , Lin John, Yi‐Chung , Chen Shui‐Tein , Chang Nein‐Chen
Published: May 2015

A new strategy for synthesizing a 4‐substituted piperidine ring uses the formal [3+3] cycloaddition reaction as the key protocol. This method provides a convenient formal synthesis of elarofiban, RWJ‐50042, tirofiban and paroxetine.
QSAR Studies on Dipeptides Based on a Combinatorial MHDV‐GA‐MLR Method
Authors: Liu Shu‐Shen , Yin Chun‐Sheng , Wang Xiao‐Dong , Wang Lian‐Sheng
Published: May 2015

A combinatorial method for estimating and predicting the biological activities of two sets of dipeptides, a set of 48 compounds and another set of 58, was developed. The molecular holographic distance vector (MHDV) was employed to characterize the structures of the peptide molecules. Preliminary selection of the MHDV descriptors was performed based on the number of the molecules having non‐zero MHDV values. The final optimal descriptors were completed by a genetic algorithm‐based variable selection procedure. Then the optimal descriptors are used to relate to the biological activities of the peptides using the multiple linear regression (MLR) method. For two panels of dipeptides, the correlation coefficient of estimations (r) are respectively 0.9651 for 48 peptides and 0.936 for 58 peptides, and the correlation coefficient of leave‐one‐out predictions (q) are respectively 0.9452 and 0.9075.
Synthesis and Characterization of Phenyl Modified PDMS/PHMS Copolymers
Authors: Yang Mei‐Hui , Lin Hsin‐Tso , Lin Chih‐Chun
Published: May 2015

A series of polydimethylsiloxane (PDMS)/polyhydrogenmethylsiloxane (PHMS)/polymethylphenylsiloxane (PMPS) random copolymers with different phenyl contents were synthesized in one step through triflic acid‐catalyzed ring‐opening polymerization of cyclic comonomers and characterized by GPC, IR and NMR. Sequential structures of the random copolymers were determined by 29Si‐NMR spectroscopy. Thermal properties of these copolymers were studied by DSC and TGA. The effect of phenyl moiety on the thermal properties of the copolymers was discussed. The refractive index (nD) increased regularly with the introducing of phenyl‐functionality as expected.
Solvent Effects on the Solvolysis of Some Secondary Tosylates. Applications of YBnOTs and YxBnOTs Scales to Mechanistic Studies
Authors: Liu Kwang‐Ting , Lin Yen‐Shyi , Duann Yeh‐Fang
Published: May 2015

The solvolysis of α‐tert‐butyl‐2‐naphthylmethyl, 9‐fluorenyl, and some 1‐aryl‐1‐tert‐butylmethyl tosylates (8–10) in a variety of solvents were studied. Both the single‐parameter Hammett‐Brown equation and the dual‐parameter Yukawa‐Tsuno equation showed linear correlations. The variation of ρ values was discussed. A new YxBnOTs scale was developed, and the YBnOTs scale was expanded. Solvent effects for a number of tosylates were examined. Excellent linear relationships observed from the single‐parameter Grunwald‐Winstein equation (Eqn. 2) for 9‐fluorenyl tosylate (10) led to the conclusion that the 9‐fluorenyl cation in the solvolysis transition state was unlikely antiaromatic. Anchimeric assistance in the solvolysis of 16–19 was discussed.
Palladium(II) Complexes Containing P∼N∼O Donors. Preparation and Reactivity
Authors: Shi Ping‐Yung , Liu Yi‐Hong , Peng Shie‐Ming , Liu Shiuh‐Tzung
Published: May 2015

Palladium complexes [(P∼N∼O)PdR]BF4 containing imine‐phosphine‐ether tridentate donor were prepared. The behavior of an ether donor, a hemi‐labile one, influences the coordination mode of a carbon ligand around the metal center. Reaction of excess styrene with [(P∼N∼O)PdMe]BF4 results in the formation of [(P∼N∼O)Pd(η3‐CH(CH3)C6H5)]BF4, which is characterized by spectral and crystal structural determination. Copolymerization of olefin and carbon monoxide catalyzed by [(P∼N∼O)PdMe]BF4 is addressed.
Reactions of Sydnone Rings with Cyclopentadiene and/or Dicyclopentadiene: Formation of Pyrazole by Utilization of Sydnones as the Synthetic Presursors
Authors: Lin Shaw‐Tao , Tien Hsien‐Ju , Huang Shul‐Man , Chen Jinn‐Tsair , Shu Jinn‐Tsair
Published: May 2015

Sydnone can be converted to pyrazoles by reacting with cyclopentadiene. These products result from direct reaction of sydnone with either cyclopentadiene or dicyclopentadiene. Among the four products, two of the compounds are verified by X‐ray diffraction analysis.
Direct Oxidative Amidation of Aldoses by Iodine in Ammonia Water
Authors: Chen Ming‐Yi , Hsu Jue‐Liang , Shie Jiun‐Jie , Fang Jim‐Min
Published: May 2015

Aldopentoses, aldohexoses and the benzylated derivatives reacted with iodine in ammonia water at room temperature to give their corresponding saccharide amides in high yields. The reactions proceeded with oxidation of the aldose hemiacetals by iodine to generate the saccharide lactone intermediates, which underwent ammonolysis in situ to give the saccharide amides.
Cytotoxic and Antiplatelet Aggregation Principles of Ruta Graveolens
Authors: Wu Tian‐Shung , Shi Li‐Shian , Wang Jhi‐Joung , Iou Song‐Chou , Chang Hsien‐Chang , Chen Yuh‐Pan , Kuo Yao‐Haur , Chang Ya‐Ling , Tenge Che‐Ming
Published: May 2015

Nineteen compounds have been isolated from the methanol extract of the root and aerial parts of Ruta graveolens. The structural elucidation of these isolated compounds were determined by the spectroscopic methods and/or comparison of the physical data with literature values. Their antiplatelet aggregation and cytotoxic activities were examined to find potent antiplatelet aggregation and cytotoxic compounds from natural resources. Among them, dictamine (5), skimmianine (7), psoralen (8), chalepensin (12), clausindin (13), and graveolinine (16) showed significant inhibition of platelet aggregation, induced by arachidonic acid and collagen. Arborinine (2), dictamine (5), isopimpinellin (11), clausindin (13), and graveoline (17) exhibited cytotoxic activity against KB, Hela, DLD, NCI and Hepa tumor cell lines.
Rice Bran as an Excellent Sorbent for Heavy Metals from Aqueous Media, 2. Determination of Related Parameters
Authors: Farajzadeh Mir Ali , Vardast Mohammad Reza
Published: May 2015

In part 2 of this report related parameters of the rice bran (as a sorbent of heavy metals) such as exchange capacity, distribution coefficients and isotherms, etc. were studied. The obtained results show that selectivity of the bran towards heavy metals such as Cu(II), Cd(II), Fe(III), Ni(II), Zn(II) and Pb(II) is very high. Also, distribution coefficients between aqueous solution and bran are more than 104 so that all cations are completely adsorbed by the bran in relatively low concentrations. The principal advantages of this sorbent are as follows: high efficiency, very high exchanging speed, cheapness (in comparison with conventional resins), performance in batch and continuous conditions and producing no environmental pollution. The only disadvantage of the bran is low exchanging capacity for some elements (but for lead it is comparable to classical resins); however, it is able to eliminate heavy metals in mg/L level and above. On the other hand, due to low cost of bran and high cost of recovery of ion exchangers there is no necessity to recover the bran. Reproducibility of the proposed method in removal of heavy metals is excellent and the relative standard deviations for eight repeated removals for all cations with the exception of iron are less than 1%.
First and Efficient Method for Reduction of Aliphatic and Aromatic Nitro Compounds with Zinc Borohydride as Pyridine Zinc Tetrahydroborato Complex: A New Stable Ligand‐Metal Borohydride
Authors: Zeynizadeh Behzad , Zahmatkesh Karam
Published: May 2015

Pyridine zinc tetrahydroborate, [(Py)Zn(BH4)2], as a new stable ligand‐metal borohydride, is prepared quantitatively by complexation of 1:1 zinc borohydride and pyridine at room temperature. This reagent efficiently reduces different aromatic and aliphatic nitro compounds to their primary amines in refluxing THF. In addition, the reduction shows chemoselectivity for aliphatic nitro compounds over the aromatic nitro compounds.
Synthesis of 8‐Desoxythunberginol A and (±)‐8‐Desoxy‐3,4‐Dihydrothunberginol A
Authors: Saeed Aamer
Published: May 2015

A two step synthesis of title isocoumarin isolated from Homalium longifolium and its conversion into corresponding 3,4‐dihydroisocoumarin has been described. 3,4‐Dimethoxybenzoyl chloride on condensation with homophthalic acid afforded 3‐(3′,4′‐dimethoxyphenyl)isocoumarin which was demethylated to furnish the 8‐desoxythunberginol A, whereas its sequential saponification, reduction and demethylation yielded the (±)‐8‐desoxy‐3,4‐dihydrothunberginol A. The synthesized compounds were examined in vitro for antibacterial activity.
Synthesis, Characterization and Bio‐activities of Novel Organotin(IV) Complexes with N‐Phthaloyl‐D‐valine
Authors: Ashfaq Muhammad , Baloch Musa Kaleem , Majeed Abdul , Khanzada Abdul Wahab Khan , Shah Wali Ullah
Published: May 2015

The synthesis and spectroscopic characterization of novel organotin(IV) complexes are described. The monomeric compound possesses trans octahedral, and the dimeric complex is of six‐coordinated skew trapezoidal bipyramidal geometry. The triorganotin(IV) complexes are assigned a polymeric trigonal bipyramidal and a tetrahedral structure. The ED50 test showed toxicity to brine shrimp naupli and bio‐activities tests of the compounds exhibited antibacterial, antifungal and excellent anti‐tumour activities.
New Annulation Techniques; Condensations of Phosphonium Ylides and Substituted 2H‐Pyran‐5‐carboxylates; Preparation of Cyclohexenonedicarboxylates and Cyclohexadienedicarboxylates
Authors: Moorhoff Cornelis M.
Published: May 2015

Substituted alkyl 2H‐pyran‐5‐carboxylates condensed with alkyl 3‐oxo‐4‐(triphenylphosphoranylidene)butanoate and alkyl 4‐(triphenylphosphoranylidene)‐2‐butenoate to form substituted 2‐vinyl‐6‐oxo‐4‐cyclohexene‐1,3‐dicarboxylates, some of which showed ecto‐parasiticidal activity in pets and cattle, and substituted 2‐vinyl‐3,5‐cyclohexadiene‐1,3‐dicarboxylates, respectively. The last mentioned product is in marked contrast to the product obtained using the corresponding arsonium analogue.
Solvent‐Free Synthesis of N,N′‐Diarylureas Using Microwave Technology
Authors: Sun Ting , Li Jing , Wang Yu‐Lu
Published: May 2015

A simple and rapid solvent‐free synthesis of N,N′‐diarylureas in a microwave oven has been reported for the first time. Nine compounds were synthesized. The reaction time is short (2∼5 min) and gives excellent yield (80–95%).
A New Method for the Synthesis of Acyl‐diazenes Using NaNO2‐Ac2O
Authors: Li Jian‐Ping , Liu Ping , Xue Wan‐Xin , Wang Yu‐Lu
Published: May 2015

An efficient and convenient method for the synthesis of acyl‐diazenes from acylhydrazines using NaNO2‐acetic anhydride as a novel oxidant agent is reported. The reaction gives excellent yields and the reaction time is not long.
Chemical Composition and the Origin of Suspension Particles in Liang‐Dong Bay (Yin‐Yang Sea), Northern Taiwan
Authors: Fang Jiann‐Neng , Yu Being‐Sheng , Chen Yaw‐Lin , Song Sheng‐Rong , Lo Huann‐Jih , Lin I‐Chieh , Liu Chia‐Mei , Liu Ya‐Jiun
Published: May 2015

A phenomenon of mixing blue and brown seawater, called “Yin‐Yang Sea”, has existed for decades in Liang‐Dong Bay. In order to determine the chemical composition and origin of pollutants in the bay, each of 5 water samples from the stream and bay were collected for chemical analyses. Meanwhile, suspension particles in the bay, the sediments on the bottom of bay and the precipitation on the bottom of the stream were also collected for chemical, X‐ray diffraction and particle size analyses.

The suspension particles are amorphous and are predominantly composed of Fe(OH)3. This is showen by the solubility products of water samples in the bay being higher than the ksp of Fe(OH)3. The deposits on the bottom of the stream also show similar results. However, the chemical concentrations of major ions, e.g. Na+, K+, Ca+2, Mg+2, Cl− and SO4−2, are much higher in the bay water than of the stream water. Nevertheless, Fe+2, Mn+2, Cu+2 and Si+4 show positive anomalies in the lower stream where the abandoned pits are located. Thus, it is assumed that minerals in the pits, such as pyrite and marcasite, are the main source supplying iron through weathering. Iron released by minerals is carried by the stream and arrives in the bay in hours. Since the oxidation rate becomes very slow in the bay because of the effects of salts and neutral pH values, most of the particles of Fe(OH)3 form in the bay gradually.
Single Molecule Spectroscopy
Authors: Latychevskaia Tatiana Y U. , Liang Kuo Kan , Hayashi Michitoshi , Chang Chung‐Hung , Renn Alois , Wild Ur S. P. , Hsu Jui‐Hung , Chang Ta‐Chau , Lin Sheng Hsien
Published: May 2015

Single molecular experiments carried out in the group of Prof. Wild in ETH Zurich, as well as the experimental and theoretical studies of several research groups in Taiwan, have been summarized in this review. It is shown that with the contemporary technologies, single molecular experiments can be carried out under a broad range of physical conditions. These includes low and room temperatures; in vacuum, in solution, in the air, or with specific pressure applied on the sample; in applied direct‐current or alternating‐current electric fields; on molecules in solid matrices, in gel, or even functioning biomolecules in vitro. Theoretical efforts have been able to help identifying the interactions of single molecules with their surroundings that modulate their static or time‐resolved spectroscopic properties. The joint experimental and theoretical effort to develop the research techniques in single molecular experiments is shown to be fruitful, and future works in this direction are important for many fields in chemistry, physics, and biology.
A Theoretical Study of N‐methlyformamide Photolysis
Authors: Chen Xue‐Bo , He Hong‐Yuan , Fang Wei‐Hai
Published: May 2015

The potential energy surfaces for N‐methlyformamide(HCONHCH3) dissociation into HCO + NHCH3 and CONHCH3 + H in the ground and lowest triplet states have been characterized with DFT, MP2 and CASSCF methods with the cc‐pVDZ basis set, while the S1 potential energy surfaces for the dissociation reactions were determined by the CASSCF/cc‐pVDZ optimizations followed by MRSDCI single‐point calculations. The mechanism of the HCONHCH3 photodissociation has been elucidated on the basis of the computed potential energy surfaces and surface crossing points.
Bifurcation Analysis of the Trans ↔ Cis Rotation of Monorotor Molecules
Authors: Cheng Hsiu‐Yao , Lai Chi‐Jung , Chang Shyang
Published: May 2015

The bifurcation analyses of the internal rotation of three different series of monorotor molecules are investigated in this paper. Our results indicate that the types of catastrophe and topological regions are related to the generic form of potential energy function and the critical points. Namely, when the double‐barrier energy function is represented as the third‐order generic polynomial of the reduced reaction coordinate, the process is isomorphic to the elementary fold catastrophe. Similarly, when the triple‐barrier energy functions are represented as the fourth‐order generic polynomial of the reduced reaction coordinate, the process is isomorphic to the elementary cusp catastrophe.
Theoretical Study of the X+YCl (X, Y=H, D) Reactions
Authors: Yao Li , Han Ke‐Li , Song He‐Shan , Zhang Dong‐Hui
Published: May 2015

Time‐dependent wave packet calculations for the reaction H+HCl and its isotopic reactions are carried out on the potential energy surface (PES) of Bian and Werner (BW2) [Bain, W.; Werner, H.‐J. J. Chem. Phys. 2000, 112, 220]. Reaction probabilities for the exchanged and abstraction channels are calculated from various initial rotational states of the reagent. Those have then been used to estimate reaction cross sections and rate constants which also are calculated and explained by the zero‐point energy and the tunneling effect. The results of this work were compared with that of previous quasiclassical trajectory calculations and reaction dynamics experiments on the abstraction channel. In addition, the calculated rate constants are in reasonably good agreement with experimental measurements for both channels.
Computations on a Series of Substituted Quinolines
Authors: Slanina Zdenêk , Hsu Ming‐Ann , Chow Tahsin J.
Published: May 2015

Computations are reported for a series of eight substituted quinolines. Their computed HOMO‐LUMO gaps have particularly been of interest as they can be measured and should correlate with some physico‐chemical properties. Structures and energetics of the selected substituted quinolines have been evaluated at several levels of theory. Interesting deviations from planarity are found in some cases. There is a good agreement with available observed thermochemical data. Effects of various computational approximations are discussed.
Clustering, Saturated Vapors, and the Atmosphere
Authors: Slanina Zdenêk
Published: May 2015

Recent heuristic computational findings of temperature increase of clustering degree in several, quite different saturated vapors are analyzed. A thermodynamic proof is presented, showing that this event should be rather common. Illustrations are primarily based on saturated steam and also on carbon vapor. Consequences for the atmosphere are discussed.
Computation of the Protein Structure Entropy and Its Applications to Protein Folding Processes
Authors: Chan Chen‐Hsiung , Lyu Ping‐Chiang , Hwang Jenn‐Kang
Published: May 2015

We have developed a general method to compute the structure entropies of protein sequences. Structure entropy gives a quantitative measure of structure conservation. This relationship is similar to that between sequence entropy and sequence conservation. Experimental studies in protein folding have suggested that residues relevant to protein folding, or the so‐called “hot spot” residues, are usually structurally conserved, though not necessarily conserved in sequences. Hence, the ability to compute structure entropy can help identify important residues related to protein folding. In this work, we have applied our approach to several model proteins frequently used in protein folding experiments. Our results suggest a close relationship between the structure entropies of residues and their rates of amide proton exchange, and we are able to identity regions of residues that are important in protein folding.
Theoretical Study of the Fragmentation of Glycine Radical Cation
Authors: Lu Hsiu‐Feng , Li Feng‐Yin , Lin S. H.
Published: May 2015

Using the CCSD(T)//B3LYP method with 6–31+G(d,p) basis sets, we report the preliminary result about four fragmentation reactions of glycine cation radical and propose possible mechanisms for several ion products found in glycine mass spectrum. There are intermediates in the reaction pathway of the fragmentation of glycine radical cation. Our result shows that the dominant fragmentation process arises from the Cα‐R cleavage by losing COOH, corresponding to the m/z 30 peck (NH2CH2+). There are two reactions generating this fragment in the four fragmentation reactions discussed in this report.