bluuebunny/crossref_metadata_2025 huggingface dataset:
Colorimetric Determination of Seleniumin Various Environmental Samples
Authors: Chatterjee Sukumar , Pillai Ajai Kumar , Gupta Vinay Kumar
Published: May 2015

A new reagent system using rhodamine‐B dye for the determination of selenium is described. The method is based on the reaction of selenium with acidified potassium iodide to liberate iodine. The liberated iodine bleaches the pink colour rhodamine‐B, which is measured at 555 nm. Beer's law is obeyed over the concentration range of 1–10 μg of selenium final solution volume of 25 mL (0.04–0.4 ppm) and the apparent molar absorptivity and Sandell's sensitivity was found to be 1.96× 105 l mol−1 cm−1 and 0.0004 μg cm−2, respectively. The method is simple, sensitive, and selective and is satisfactorily applied to micro‐level determination of selenium in various environmental and cosmetic samples.
Synthesis of Novel N‐Pyridylcantharidinimides by Using High Pressure
Authors: Lin Pen‐Yuan , Shi Sheng‐Jie , Lin Lun‐Huei , Chen Hsue‐Fen , Hsu Feng‐Lin
Published: May 2015

The recently described pressure reaction in the presence of trithylamine with subsequent thermal (200°C) cyclization provided 13N‐pyridylcantharidinimides 4a‐4m from aminopyridines and cantharidin in yields of 15–83%. 2‐Amino‐3,5‐dichloropyridine failed to yield 4n.
Spectroscopic Characterization of Some Tetradentate Schiff Bases and Their Complexes with Nickel, Copper and Zinc
Authors: Abd‐Elzaher Mokhles M.
Published: May 2015

Three ligands have been formed by the 1:2 molar condensation of o‐phenylenediamine with salicyldhyde, 2‐hydroxy‐1‐naphthaldhyde or o‐hydroxyacetophenone. The potentially tetradentate ligands are N,N′‐bis(salicyldhyde)‐o‐phenylenediamine(SalophH2), N,N′‐bis(2‐hydroxy‐1‐naphthaldhyde)‐o‐phenylenediamine (NophH2) and N,N′‐bis(o‐hydroxyacetophenone)‐o‐phenylenediamine (AophH2), respectively. These ligands form complexes (1:1 molar ratio) with nickel, copper and zinc ions. The complexes have been characterized by IR, 1HNMR, MS, uv/vis spectra in addition to elemental analysis. The spectral data of the ligands and their complexes with nickel, copper and zinc are discussed in connection with the structural changes which occur due to complexation.
Infrared Chemical Sensor for Detection of Chlorinated Phenols in Aqueous Solutions Based on a ATR Waveguide Coated with Structural Designed Polymers
Authors: Yang Jyisy , Hon Hau‐Huang
Published: May 2015

A combination of solid phase micro‐extraction (SPME) with attenuated total reflection (ATR) infrared spectrometry provides a fast and sensitive way to detect organic compounds in aqueous solutions. It is especially useful for detection of chlorinated organic compounds in environmental samples. Currently, analyses of organic compounds in aqueous solutions are limited to low‐polarity compounds by the SPME/ATR‐IR sensing method. This limitation was mainly caused by the low polarity nature of the SPME phase. To increase the capability of this method to detect more polar compounds and also to increase the sensitivity in detection of organic compounds, the principle of “like‐dissolve‐like” was used to design a specific SPME phase for a certain class of chlorinated compounds. To demonstrate this concept, chlorinated phenols were used as probe molecules and polyvinyl chloride was chemically modified with phenol, ‐naphthol and ‐naphthol to provide SPME phases with a similar chemical structure to chlorinated phenols. These polymers were used as SPME phases and their performance were compared with the commonly used SPME phases (i.e., polystyrene and polyisobutylene). Results indicated that naphthols attached to PVCs provided much lower compactness, which allows fast speed in absorption of phenols. Meanwhile, due to the structural similarity between naphthols attached to PVCs and phenols, much higher partition coefficients were found for these chemically modified PVCs than conventionally used polymers. To further increase the sensitivity for analysis of chlorinated phenols, the common influencing factors, such as pH values and salt effect were also investigated. Apparently, pH values of the solutions did not influence the structure of the modified PVCs significantly. In absorption of chlorinated phenols in aqueous solutions with different pH values, the observed IR signals were decreased greatly in pH higher than 6 due to the charged form of chlorinated phenols that were presented. Results of the salt effect indicated that three times stronger of IR signals can be obtained if 20% (w/vol) of NaCl was added.
Chemical Cleaning of Microfiltration Membranes Fouled by Whey
Authors: Madaeni Sayed Siavash , Sharifnia Shahram , Moradi Gholamreza
Published: May 2015

Millipore hydrophobic polyvinylidene fluoride (PVDF) microfiltration membranes were used for whey processing. Fouled membranes were cleaned with acid (HCl), alkaline (NaOH) and surfactant (Triton‐X100). The latter resulted in maximum flux recovery and resistance removal. Hydrochloric acid had a moderate effect and sodium hydroxide was the weakest cleaning agent. This is due to the cleaning strength of emulsifiers compared to acid or alkali. However acids are more efficient than alkaline solutions for removal of mineral compounds which remain on the membrane surface.

Cleaning efficiency depends on the concentration of cleaning agent being higher for higher surfactant concentration. For acids and alkali, the efficiency increases with increasing the concentration of the reagent reaches a maximum (optimum concentration) and then decreases. This can be explained by changes in permeability of the deposit layer with the concentration of the cleaning agent. Another explanation is the breakage of proteins by acid or alkali which produces more fouling materials and causes less cleaning efficiency.

Operating conditions affect the cleaning process. At higher stirring speeds (turbulent flow) or longer cleaning time better removal of deposits and higher cleaning efficiency were observed. The sequential cleaning process may or may not improve the cleaning efficiency. When acidic cleaning was followed by washing with a surfactant an improvement was achieved. This can be attributed to the incomplete removal of deposits by acid. However further cleaning with acid can not improve the cleaning efficiency.

During whey processing fouling occurs by deposition of foulants of mostly proteins and macromolecules on the membrane surface or in the membrane matrix. Large substances (compared to the membrane pores) settle on the membrane surface and the small species penetrate and are adsorbed in the membrane pores. Cleaning dissolves and removes the adsorbed foulants from the membrane.
Sesquiterpenes and Flavonoids from Serratula Strangulata
Authors: Dai Jing‐Qiu , Hou Zhen‐Fu , Zhu Qi‐Xiu , Yang Li , Li Yu
Published: May 2015

Phytochemistry investigation of the whole plants of Serratula strangulata has led to the isolation of two sesquiterpenes, six flavonoids, and two isoflavonoids. Among these, a sesquiterpene and two flavonoids are new compounds. The structures of these new compounds were elucidated by spectroscopic methods and 2D NMR techniques.
Confined Atoms in Clusters Bubbles Dots and Fullerenes
Authors: Connerade Jean‐Patrick , Kengkan Prasert , Semaoune Rachid
Published: May 2015

We present a brief review of the subject of confined atoms, in which we emphasise the origins of the subject and its most recent applications. Emphasis is placed on the wide variety of situations to which the idealised quantum mechanical treatment is relevant. Both the nonrelativistic and relativistic methods are contrasted; an example of confinement in the Dirac‐Fock scheme is given and some special problems connected with relativistic confinement are mentioned. Finally, we present a discussion of the quantum pressure, and a novel, dimensionless choice of variables which allows universal atomic behaviour for confined atoms to be visualised.
Ion Recoil Following (2+1) REMPI of Nascent Atoms ‐ The Effect on Nascent Velocity Distributions in Velocity Map Imaging
Authors: Parker David H. , Delmdahl Ralph F. , Bakker Bernard B. L. G. , Loock Hans‐Peter
Published: May 2015

Velocity map imaging has achieved thus far are solution at 1eV kinetic energy release of ∼30 meV, thus 3% ΔE/E. In order to further improve the resolution we need to look more critically at one of the assumptions in the imaging method–that the conversion of neutral fragments to ionic fragments using the standard REMPI technique does not significantly change the nascent velocity distribution of the neutral species. This is shown in this paper to be a questionable assumption in many cases. The effects of ion recoil due to the detection process in the photodissociation of HI and O2 are predicted to fall in the 2–3% range for normal conditions in velocity map imaging. Recoil effects are illustrated for REMPI of D atoms cooled in a supersonic discharge expansion. Dramatic effects of recoil are also illustrated here for the photodissociation of HI. Recoil effects are shown to play a role in the final resolution of many types of velocity mapping experiments.
An Experimentalist's View of the H− Ion
Authors: Bryant H. C.
Published: May 2015

We present a short survey of selected experimental studies of the negative ion of hydrogen over the past twenty‐three years at the 800 MeV linear accelerator at Los Alamos. Experimental techniques are described and heuristic models are used to explain and motivate experimental results. We discuss the first observations of the 1P resonances just below n = 2, the so‐called “Feshbach” and “shape” resonances, seen in photodetachment. As one experimental question is answered, another question becomes exposed, for example, the effects of electric fields on the spectroscopy of the ion. Techniques used to convert the H− ion into a dual‐beam interferometer moving near the speed of light are described. Experimental data taken near thresh old in an electric field are displayed on a universal plot. Multiphoton detachment extends the spectroscopy of the ion to singlet states that would be unreachable by single photodetachment processes. A thin foil also is used to probe the ion structure. Using ion beams in the 35 kV range, 2‐photon measurements of an isotope shift between Hand D− reveal two‐electron correlation consequences. Finally we ad dress the question, “Why has the shape resonance not been seen in astrophysical observations?
Structure and Dynamics in Alkaline‐earth Atoms
Authors: Aymar Mireille , Lecomte J. M. , Luc‐Koenig E. , Millet M.
Published: May 2015

In this paper we will show how the approach combining the eigenchannel R‐matrix method to the techniques of multichannel quantum‐defect theory (MQDT) is a very powerful method to obtain realistic descriptions of complex spectra of alkaline‐earth atoms in the energy domain and to study the dynamics of various processes in these spectra. Several illustrations will be presented. Those on structure will concern photoionization spectra of barium and strontium at high energy and two‐photon ionization processes in magnesium and strontium. Then, recent results on the dynamics of coherent ionization processes will be presented.
Resonance Scattering in the Three‐Body Systems of Atom‐diatom and Relevance to Condensed Matter Physics
Authors: Salk Sung‐Ho Suck
Published: May 2015

Three‐body resonance scattering of atom‐diatomic molecule systems involving internal excitations is discussed by fully allowing the topological phase (Berry phase) contribution. Earlier a generalized formalism (Phys. Rev. A 1996, 53, 2433) of the three‐body resonance scattering was presented by introducing the gauge potential (Berry connection). Based on this study we provide additional information on topological importance in resonance scattering involving the atom‐diatomic molecule systems. The massive gauge field (Berry connection) contribution which arises from a broken symmetry is discussed. Its relevance to condensed matter physics will be briefly high lighted in connection with our recent theory of super conductivity (Phys. Rev. B 1999, 60, 6324).
Q‐Number Essence of the Time and Time‐Energy Uncertainty Relation
Authors: Quang Nguyen Vinh
Published: May 2015

It is proved that time must be a q‐number, which is defended against Pauli's argument indifferent forms. A new form of the commutator of a Hamiltonian with time is presented. The time‐energy uncertainty relation is derived on the same solid basis as the momentum‐position one.
Some Problems in the Theory of Trapping States
Authors: Quang Nguyen Vinh , Phong Pham Hong
Published: May 2015

After the 1997 Nobel Prize in Physics was awarded to Chu, Cohen‐Tannoudji, and Phillips, great interest returned to both the Bose‐Einstein condensation phenomena and the theory of trapping states. In this present work the mixing‐states principle, which is proved for the case of two arbitrarily degenerate levels by V. Q. Nguyen [Opt. Com. 1985, 5, 335] is extended to a system of three arbitrarily degenerate levels resonantly interacting with the equal‐detuning two‐mode laser field. The theorem for the maximal number of trapping states is proved. The consequence of the theorem is the “for bid den rule”: trapping states do not exist for a V‐system or for the lambda‐type system, in which the sum of the degenerate multiplicity of two low lev els is not greater than one of high level.
Hartree‐Fock Deformed Jellium Calculations for Metallic Clusters
Authors: Lyalin Andrey , Semenov Sergey , Solov'Yov Andrey , Cherepkov Nikolai , Connerade Jean‐Patrick , Greiner Walter
Published: May 2015

We have developed the Hartree‐Fock jellium model for deformed metal clusters by treating the quantized electron motion in the field of the spheroidal ionic jellium background in the Hartree‐Fock approximation. Using this model, we have calculated single electron energy levels as a function of the cluster deformation parameter for a series of sodium clusters with the number of atomsNin a cluster ranging from 4 to 40. We have established that the cluster deformations corresponding to the minimum total energy of the oblate and prolate clusters are in reasonable agreement with the experimental data and the predictions of other theoretical models.
For the Development of Femto Second X‐Ray Laser Using Inner‐Shell L23M1 Transition in Ca
Authors: Kim Dong Eon , Son Sang Hyun , Kim Jae Hoon , Tóth Csaba , Barty Chris P. J.
Published: May 2015

A new physical scheme for femto second X‐ray lasers, where the upper lasing is pumped by X‐ray photons and the lower lasing level is depopulated via a Coster‐Kronig radiationless transition, is analyzed for Ca. The transition wave length is 4.1 nm, which is in side the water window. The peak spectral brightness of the X‐ray laser out put at 4.1 nm is predicted to be as large as 5× 1025 photons/sec./(mm2 mrad2 0.1% band width), which is 4 to 5 orders of magnitude brighter than a typical undulator radiation in the similar spectral region. In addition to the high flux, the expected duration of X‐ray lasing of ∼3 fs. will be useful for the study of fast dynamics in physical and biological sciences.
Effects of Imperfect Gate Operations in Shor's Prime Factorization Algorithm
Authors: Guo Hao , Long Gui‐Lu , Sun Yang
Published: May 2015

The effects of imperfect gate operations in implementation of Shor's prime factorization algorithm are investigated. The gate imperfections may be classified into three categories: the systematic error, the random error, and the one with combined errors. It is found that Shor's algorithm is robust against the systematic errors but is vulnerable to the random errors. Error threshold is given to the algorithm for a given number N to be factorized.
Theoretical Study of Electron‐Impact Ionization of He‐Like Ions
Authors: Kuo Tien‐Yow , Huang Keh‐Ning
Published: May 2015

We apply the two‐potential distorted‐wave approximation to study the electron‐impact ionization of He‐like ions. The relativistic and non‐relativistic total cross sections for incident energies from 1 to 10 ionization‐energy units are calculated. Results are compared with other theoretical calculations and experimental data. Systematic behaviors along the isoelectronic sequence are studied.
Doubly Charged Molecular Ions Studied by Double Charge Transfer Spectroscopy
Authors: Furuhashi Osamu , Kinugawa Tohru , Nakamura Nobuyuki , Masuda Suomi , Yamada Chikashi , Ohtani Shunsuke
Published: May 2015

We have developed a double charge transfer (DCT) spectroscope to study doubly charged molecular ions (dications). In the course of the development, DCT spectra of N2, CO, and NO has been ob served with energy resolution of about 0.5 eV. The spectral profiles observed have shown the Franck‐Condon (FC) behavior. We have made an effort to in crease the resolution up to about 140 meV, which is much better than those (1–1.5 eV) reported in previous works. In the present measurement, the vibrationally resolved DCT spectrum for N2++ could be obtained for the first time. The observed peak structures agree well with those calculated using FC factors, differing meaningfully from the spectra taken with Auger electron spectroscopy (AES) and thresh old photoelectrons coincidence (TPEsCO) spectroscopy. The DCT spectroscopy might be a powerful method to study the potential curves of short‐lived dications.
Classical Trajectory Study of the HFCO → HF + CO Reaction. II. Mode Specificity, DFCO Dissociation Dynamics, Effects of Rotational Energy
Authors: Budenholzer Frank , Lin Po‐Shen
Published: May 2015

Classical trajectories have been calculated for the unimolecular dissociation reaction H(D)FCO → H(D)F + CO over a modified form of the electronic ground state potential surface of Wei and Wyatt [J. Phys. Chem. 1993, 97, 13580]. The modifications of the potential energy surface and the method of calculating the trajectories are de scribed in an earlier publication from our laboratory [J. Phys. Chem. A. 1998, 102, 947]. Trajectories were initiated with the classical zero point energy distributed randomly in the six normal modes of the molecule and an additional approximately 60 kcal/mol distributed in one of the six normal modes. Clear evidence of mode specificity was found in that the excitation of the six different modes leads to significantly different rates of reaction: CH stretch > CH bend ≅ CF stretch ≥ CO stretch ≅ FCO bend > out of plane bend. For DFCO, mode specificity is considerably less apparent in that the range of life times for the six normal modes is less than half that for HFCO. Average product CO and HF distributions were also determined for both HFCO and DFCO dissociation. To investigate the degree of IVR between various modes, trajectories were calculated with the same initial energy approximately equally divided between two different initial modes. Finally, trajectories were calculated to study the effect of increasing rotational energy on the rate of HFCO dissociation. These results are discussed in terms of general theories of reaction rates, recent theoretical treatments of HFCO dissociation and experimental results.
High‐Pressure and Concentration‐Dependent Studies on C‐H—O Interactions of Binary Aqueous Mixtures: Formic Acid/D2O and Acetone/D2O
Authors: Chao Ming‐Chi , Weng Nai‐Hsin , Chang Hai‐Chou , Jiang Jyh‐Chiang , Lin Sheng Hsien
Published: May 2015

The C‐H—O interactions of formic acid and acetone aqueous solutions were studied under various concentrations. The infrared spectra of acetone/D2O were also measured as a function of pressure. The C‐H stretching frequency of formic acid reveals a red‐shift with dilution. On the other hand, upon diluting acetone with D2O, the blue‐shift with dilution in C‐H stretching frequency was observed. Further high‐pressure study provides the experimental evidence for the enhancement of hydrophobic hydration as the sample was compressed to high‐pressure ices, while C‐H vibration of acetone, being trans formed from liquid to high‐pressure ice VII, are altered into a band located at ∼2950 cm−1. The C‐H—O inter action may be a distinct possibility to understand the band‐shape and frequency‐shift of the C‐H stretching modes of formic acid/D2O and acetone/D2O.
Laser‐Induced Alignments of Symmetric and Asymmetric Top Molecules
Authors: Chen Kuo‐Mei
Published: May 2015

Analytic expressions of the distribution function of figure axes of symmetric and asymmetric top molecules under a polarized one‐photon excitation are de rived by the density matrix theory. To prepare maximally aligned reactants, those formulas are useful in stereodynamic experiments when the optical alignment techniques are utilized.
Transient Frequency Modulation Spectroscopy and 266 nm Photodissociation of Bromoform
Authors: Liu Wen‐Ling , Chang Bor‐Chen
Published: May 2015

A high‐resolution absorption spectrometer, based on the combination of frequency‐modulation (FM) and diode laser techniques, has been constructed to investigate the reaction intermediates in the 266 nm laser photolysis of bromoform (CHBr3). The absorption spectrum of HCBr corresponding to the electronic transition was successfully obtained. We also found that the nascent HCBr is electronically excited. These data indicate that in the reaction path way we observed, the first step of the 266 nm photolysis is a two‐photon process and HCBr is one of the primary intermediates. The electronically excited HCBr absorbs one or two more photons to produce the electronically excited CH radical.
Theory of Medium‐Induced Optical Activities
Authors: Hsu F. C. , Kuo Y.‐T. , Shiu Y.‐J. , Liang K. K. , Hayashi M. , Chang T.‐C. , Lin S. H.
Published: May 2015

In this paper, using the dipole‐dipole interactions to de scribe the interaction between the system molecule and medium molecules, a theory of medium‐induced optical activity has been developed. We have shown that the symmetry technique can be used to determine the types of electronic states that can be involved in the medium‐induced optical activity and that the octant rule can be deduced by using our theory.
Investigations of Ultrafast Dynamics in Light‐emitting Polymers
Authors: Chang R. , Hayashi M. , Liang K. K. , Lin S. H.
Published: May 2015

A microscopic model is constructed to describe the excited states of MEH‐PPV in thin film. It is suggested that in the high energy region, the nature of excited states in the film is very similar to the species observed in solution phase. Moreover the processes of energy transfer, vibrational relaxation and dissipation are considered to occur simultanesously, in contrast to the usual argument that assumes exciton migration occurs after vibrational motion reaches thermal equilibrium. In the low energy region, corresponding to the red‐edge of absorption, the excited state behaves differently. We assume that there exists a low energy species due to the enhancement of coplanarity of polymers in thin film and the absorption spectrum can be fitted.
Characteristics of Lariat Crown Ether‐Copper (II) Ion‐Selective Electrodes
Authors: Su Chia‐Ching , Ueng Chuen‐Her , Liu Lilian Kao
Published: May 2015

An ion‐selective electrode using ionophore 2′‐picolyl sym‐dibenzo‐16‐crown‐5 ether as membrane carrier, sodium tetraphenylborate (NaTPB) as an anion excluder, and 2‐nitrophenyl‐octyl ether (NOPE) as the plasticing solvent mediator has been successfully developed. This electrode exhibits al in ear response with a slope of 42 mV/decade in concentration ranging from 10−5 molL−1 to 10−1 molL−1, slightly larger than the 30 mV expected from the one‐to‐one complex. The reason for the super‐Nernstain slope is the partial dimmer formation in side the membrane of the electrode, because this dimmer [Cu(C25H27NO6)2(H2O)2] 2ClO4, has been isolated and confirmed by single crystal X‐ray crystallography. The detection limit for the cop per (II) ion was estimated to be 1 × 10−6 molL−1. Electrades composed of other plasticing solvent mediators such as tris(2‐ethylhexyl) phosphate (TOP), bis (2‐ethylhexyl) sebacate (DOS) and dibutyl phthalate (DBP) were also investigated. Stability constants (logKs) of the two to one and the one to one 2‐picolylsym‐dibenzo‐16‐crown‐5 ether‐Cu (II) complexes have been determined by potentiometric titration in methanol.
Application of Wavelet Neural Network to the Prediction of Gas Chromatographic Retention Indices of Alkanes
Authors: Yin Chunsheng , Guo Weimin , Lin Teng , Liu Shushen , Fu Rongqiang , Pan Zhongxiao , Wang Liansheng
Published: May 2015

A wavelet neural network (WNN) is employed to create a quantitative structure‐retention index relationship, which correlates the novel molecular distance edge vector (MDEV)‐consisting of ten elements to Gas Chromatographic retention indexes (RIGC) of Alkanes. The RIGC has been calculated by the WNN from the molecular topological descriptors of examined alkanes. In this work, the RIGC estimated and predicted by conventional neural networks (say back propagation neural networks, BP) has also been provided. The excellent predicted results with a correlation of 0.9996 and standard deviation of 5.0598 suggest that the WNN technique is a powerful tool in QSAR/QSPR modeling and superior to the BP neural networks.
The HPLC Analysis of the Concentration and Enantiomeric Purity of Selected Amino Acids in Two Highly Fermented Foods
Authors: Chen Shushi , Chen Nan‐Hurng
Published: May 2015

A HPLC system linked to a variable wavelengths UV detector was used to sequentially determine the total concentration and enantiomeric composition of two selected free amino acids (leucine, phenylalanine) in two highly fermented foods, bean curd and paste soy bean (i.e., miso), after their derivatization with N‐benzoyl chloride. As was expected, fermented bean curds tended to have a higher percentage of D‐enantiomers and greater total amount of amino acids than paste soy beans or fermented soy beans as reported previously. In one case, the relative amounts of D‐phenylalanine and D‐leucine exceeded 40% of the individual amino acids. Interestingly, paste soy bean made in Japan is found to be better than that made in Taiwan in terms of a higher total level of amino acids and a lower percentage of D‐enantiomers. In most samples, leucine was found to have a lower average percentage of D‐enantiomer but higher total concentration than phenylalanine. This finding is consistent with what was observed for fermented soy beans. Only a trace of amino acids (leucine, phenylalanine) was found in raw soybeans and bean curd, which was thought to be a result of a lack of microbial activities (e.g., fermentation, aging, etc.).
Synthesis of Arylnaphthoquinones and Their Reactions with o‐Substituted Primary Aromatic Amines
Authors: Fandy Ragab F. , Abbas Hessan H. , Al‐Hussaini Ayman S. , Hammam Ahmed S.
Published: May 2015

Cycloaddition reaction of 2‐aryl‐1,4‐benzoquinones 1a‐d with a number of different dienes, namely 2,3‐dimethylbutadiene; 1,4‐diphenylbutadiene and anthracene yield 2‐aryl‐6,7‐dimethyl‐1,4‐ naphthoquinones 3a,b; 2,5,8‐triphenyl‐1,4‐naphthoquinone 4 and 2‐aryl‐1,4,9,10‐tetrahydro‐9,10‐o‐benzoanthracene‐1,4‐dione 5, respectively were investigated. In addition, the cycloaddition reaction of 2‐aryl‐1,4‐benzoquinones 1d,e with 2,3‐dimethylbutadiene was also investigated to yield 2‐aryl‐5,8‐dihydro‐6,7‐dimethyl‐1,4‐naphthohydroquinones 2a,b. Cyclocondensation reactions of Diels‐Alder adducts 2b, 3b, 5a with ethylenediamine, o‐substituted primary aromatic amines gave quinoxaline, phenazine, phenoxazine and phenothiazine ocyclic derivatives 6–14.
An Acid‐Catalyzed Fragmentation Reaction of a Triamine‐Linked Acridine Dimer
Authors: Chou Shan‐Yen , Yin Wei‐Kung
Published: May 2015

An acid‐catalyzed cleavage of the C‐Nϵ bond from Nϵ‐(2,3,4,5‐tetrahydroxyvaleryl) substituted side chain and/or its acetonide form of a triamine‐linked acridine dimer is de scribed. An envisaged multi‐neighboring group‐assisted solvolysis reaction mechanism is proposed.
Thermodynamic Studies of Myelin Basic Protein upon Interaction with Zinc
Authors: Saboury Ali Akbar , Saeidian Shahriar , Sanati Mohammad Hosain , Moosavi‐Movahedi Ali Akbar , Alasti Fatameh
Published: May 2015

The interaction of myelin basic protein (MBP) from bovine central nervous system with divalent zinc ion was studied by UV‐Vis titration spectrophotometry and isothermal titration calorimetry techniques at 27°C in Tris buffer solution at pH = 7.2. MBP has one binding site for a zinc ion. The binding of a zinc ion is endothermic (ΔH = + 159 kJ mol−1) with a dissociation binding constant of 0.445 μM. The results obtained by two previous methods of isothermal titration spectrophotometry and calorimetry are similar and consistent with the result obtained from a new calculation method of calorimetric data analysis according to the Scatchard plot.
Triphenylphosphine‐Mediated Reduction of Electron‐Deficient Propargyl Ethers to the Allylic Ethers
Authors: Tsai Ming‐Shan , Rao U. Narasimha , Wang Jeng‐Rong , Liang Chung‐Hao , Yeh Ming‐Chang P.
Published: May 2015

Semihydrogenation of α,β‐unsaturated ynoates and ‐ynones bearing a γ‐alkoxy group can be performed using triphenylphosphine and water. α,β‐Unsaturated ynoates were reduced to a mixture of cis and trans α,β‐unsaturated enoates, whereas, ynones were reduced to trans α,β‐unsaturated enones as the only products.
Spin Trapping Studies on Radical Cations of Styrene
Authors: Ho Tong‐Ing , Lin Chiou‐Rong , Pan Kai , Hsu Chi‐Wei
Published: May 2015

The radical cat ions of styrene (π‐type), generated by photosensitized electron‐transfer of 1,4‐dicyanobenzene (DCB), using 2‐methyl‐2‐nitrosopropane (MNP) as spin trap ping agents and nucleophiles as the co‐reactant were investigated. The spin‐trapped nitroxide radicals were subjected to HPLC‐ESR and mass spectroscopic studies. Long‐range hfsc were obtained by resolution enhancement. Mass spectral fragmentation pat terns sup port the regioselective formation of the trapped nitroxides, which is derived from the anti‐Markovnikov addition of the methanol to the β‐position of the styrene cationradicals.
Cationic Phosphine‐imine ρodium(I) Complexes and Their Activity on Catalysis of Phenylacetylene Polymerization
Authors: Reddy K. Rajender , Lin Chi‐Feng , Lee Gene‐Hsiang , Peng Shie‐Ming , Chen Jwu‐Ting , Liu Shiuh‐Tzung
Published: May 2015

A series of phosphine‐imine rhodium(I) complexes have been prepared and characterized by both spectroscopic and X‐ray single crystal analyses. Their activity on catalytic polymerization of phenylacetylene is investigated. The study of the solvent effect on polymerization shows that aqueous medium can in crease the productivity of polymer.
Ole Fin Complexes of Silver(I) and Copper(I)β‐Diketonates
Authors: Chow Tahsin J. , Lm Shou‐Shun , Chi Kai‐Mmg , Lin Kuan‐Jiuh
Published: May 2015

Reactions of silver(I) and copper(I) 1,1,1,5,5,5‐hexafluoroacetylacetonate (hfacac) with dienes 1, 2 and 3 resulted in some stable complexes. All of them showed an equal molar ratio of hfacac to diene per coordinated metal ion. The structure of Ag(hfacac)(1)(THF) 6 was solved by X‐ray diffraction analysis. The complex crystallized in the monoclinic space group P21/n with a = 6.342(3), b = 32.891(7), c = 11.680(2) Å, and z = 4. It was mononuclear with inclusion of a solvent molecule. Since the C2v symmetry of 3 retained upon forming both silver(I) and Cu(I) complexes, a fast equilibrium of dissociation/recombination must have happened in the solutions. The changes of 1H and 13C NMR chemical shifts caused by coordination were measured.
The Chemical Constituents from the Aril of Cassia Fistula L.
Authors: Lee Ching‐Kuo , Lee Ping‐Hung , Kuo Yueh‐Hsmng
Published: May 2015

Twenty‐seven compounds including eight long‐chain hydrocarbons, 1‐hexacosanol (1), 1‐octacosanol (2), palmitic acid (3), stearic acid (4), oleic acid (5), linoleic acid (6), heptacosyl eicosanate (7), glyceryl‐1‐tetraeicosanoate (8); three sterols, β‐sitosterol (24), stigmasterol (25), β‐sitosteryl‐3‐O‐D‐glucopyranoside (26); one triterpene, lupeol (27); eight anthraquinones, chrysophanol (9), emodin (10), physcion (11), citreorosein (12), rhein (13), rhein methyl ester (14), ziganein (15), 1,4,5‐trihydroxyanthraquinone (16); two coumarins, isoscopoletin (17), scopoletin (18); two chromones, 2,5‐dimethyl‐7‐hydroxychromone (19), 2,5‐dimethyl‐7‐methoxychromone (20); three aromatic compounds, isovanillic acid (21), vanillic acid (22), and 2,4‐dihydroxybenzaldehyde (23), were isolated and identified from the bark of Cassiafistula. Their structures were determined on the basis of spectral data.
Spectrophotometric Determination of Palladium(II) with New Re Agent N‐octyl‐N′‐(Sodium P‐Amminobenzenesulfonate)Thiourea (OPT)
Authors: Ma Dong‐Lan , Li Ying , Ltf Quan‐Jian , Wang Yu‐Lu
Published: May 2015

The color reaction of palladium(II) with the new reagent OPT was studied. In the presence of cetyltrimethyl ammonium bromide (CTMAB), in pH 5.0–5.6 HAc‐NaAc buffer solution, a yellow‐brown soluble complex with the ratio of 1:4 was formed. The maximum absorption was at 299.0 nm, the apparent molar absorptivity ϵ299.0 nm = 1.38×105l mol−1 cm−1. Beer's law was obeyed in the range of 2–12 μg Pd(II)/25 mL. The method's sensitivity and selectivity were very good. It could be used to determine palladium(II) in a catalyst with satisfactory results.
The Competitive Reactions between Electron Transfer and Radical Addition in Free Radical Reactions
Authors: Wu Yuh‐Wern , Lu Cheng‐Yi
Published: May 2015

The photolytic reactions of 2‐substituted αlyl chloride with t‐BuHgCl In different solvents were Investigated. The reactions proceed the SH2′ reaction mechanism except the substituent is a strong electron‐releasing group. The electron transfer process becomes more competitive with the radical addition process when the substituent is a strong electron‐releasing group. When the substituent is a strong electron‐releasing group such as ‐CH2SiMe3, there action in CH2CN shows pronounced electron transfer process while the reaction in DMSO or THF involves both of the SH2′ and the electron transfer processes. The reaction is sol vent dependent. An electron transfer mechanism is discussed.
Studies on the 1,3‐Dipolar Cycloaddition of 3‐Arylsydnone Nitrile Oxides to Cyclic Alkene Compounds
Authors: Smh Mei‐Hsiu , Her Kuei‐Hua , Yeh Mou‐Yung
Published: May 2015

Cycloadditions of 3‐arylsydnone nitrile oxides (1) with various cyclic alkenes led to 4‐isoxazolyl or 4‐isoxazolinyl sydnones. The reactions were controlled either by the HOMO (dipole)‐LUMO (dipolarophile) interaction or by the LUMO (di pole)‐HOMO (dipolarophile) interaction. The former were accelerated by electron withdrawing substituted dipolarophiles, such as 2‐cycloalken‐1‐ones (3a∼3c), etc., while the latter were improved by the dipolarophiles with electron‐donating substituents, such as 1‐morpholino‐1‐cyclohexene (3d), 1,3‐cyclohexadiene (3e). Be sides that, methylenecycloalkanes 3f∼3g are more active than cyclohexene to ward cycloaddition with nitrile ox ides 1. The cycloaddition ad ducts may serve as useful building blocks in synthesis through chemical modification and ring cleavage, and also be employed in the syntheses of many natural products with significant and special activities.
Facile Synthesis of N‐Substituted Isothiazol‐3(2H)‐Ones Using a Hypervalent Iodine(III) Re Agent
Authors: Kang Iou‐Jiun , Wang Huey‐Min , Huang Hsin‐Yu , Chen Ling‐Ching
Published: May 2015

Treatment of N‐substituted (Z)‐3‐(benzylsulfanyl)propenamides (4) with phenyliodine(III) bis(trifluoroacetate) containing trifluoroacetic acid resulted in an interrupted Pummerer‐type reaction to give N‐substituted isothiazol‐3(2H)‐ones (5) rather than the normal Pummerer‐type products.
The Synthesis of Symmetrically Octa‐Substituted Phthalocyanines and Their Physical and Photo‐Physical Properties
Authors: Gao Detao , Xu Haitao , Yan Tiantang , Peng Bixian
Published: May 2015

A series of symmetrically substituted phthalocyanines have been synthesized from 3,6‐dialkoxyphthalonitrile and the corresponding metal salts. All of these complexes are extremely soluble in chloroform. Their melting points vary greatly with their different substituents. Their structures are confirmed by elemental analysis,1H NMR, UV‐VIS.
The Ionic Conductivity of Solid Electrolytes for Li4+xMxSi1–xO4‐yLi2O (M=Al, B) Systems
Authors: Chen Ru‐Fen , Song Xiu‐Qin
Published: May 2015

The Li4+xMxSi4+xO4‐yLi2O (M=Al, B; x = 0 to 0.6, y = 0 to 0.5) ion conductors were prepared by the Sol‐Gel method and examined in detail. The powder and sintered samples were characterized by DTA‐TG, XRD, SEM, and AC impedance techniques. The experimental results show that the conductivity and sinterability in creased with the amount of excess lithium oxide in the silicate. The Li2O phase acts as a flux to accelerate the sintering process and to obtain high conductivity of grain boundaries. The particle size of the sintered pellets is about 0.25 μm. The maximum conductivity at 200 °C is 5.40 × 10−3s cm−1 for Li4.4Al0.4 Si0.6O4‐0.3Li2O.
An Improved Oxidative Cleavage Method for Large Scale Preparation of Some Acid‐Labile Aglycones from Glycosides
Authors: Wang Perng‐Haur , Jou Sheng‐Jye , Chen Wen‐Chuan , Lee Shoei‐Sheng
Published: May 2015

A practical method for large‐scale preparation of acid‐labile aglycones including protopanaxadiol, protopanaxatriol, cycloastragenol, and jujubogenin from the corresponding glycoside containing fraction was developed. The key point of this improved method is to generate and maintain the critical reaction conditions, anhydrous and strongly basic, in situ. This effort over comes the weakness of the reported method for oxidative cleavage of glycones and scales up the preparation of these acid‐labile aglycones for further studies.
Three New Phenolic Compounds from Nepeta Prattii
Authors: Hou Zhen‐Fu , Tu Yong‐Qiang , Li Yu
Published: May 2015

Three new phenolic compounds, 2‐(glycer‐2‐yl)‐5‐(2‐hydroxyethyl)phenyl‐O‐β‐D‐glucopyranoside, 2‐(glycer‐2‐yl)‐5‐(2‐hydroxyethyl)phenyl‐O‐β‐D‐galactopyranoside and ethyl 3‐(3,4‐dihydroxyphenyl)lactate were isolated from Nepeta prattii. Their structures were elucidated by spectral methods.
The Constituents of Euchresta Formosana
Authors: Lo Wen‐Li , Chang Fang‐Rong , Hsieh Tian‐Jye , Wu Yang‐Chang
Published: May 2015

A new flavanone, euchrenone a17 (1), along with eighteen known compounds, glabrol (2), euchrenone a2 (3), formononetin (4), 7‐methoxy‐2′,4′‐dihydroxyisoflavone (5), 3‐(3,4‐dimethoxy‐phenyl)‐7,8‐dihydroxy‐chromon‐4‐one (6), 5,7,2′‐trihydroxy‐4′‐methoxyisoflavone (7), 2′‐hydroxygenistein (8), euchrenone b1 (9), euchrenone b2 (10), euchrenone b16 (11), vanillin (12), p‐hydroxybenzoic acid (13), medicagol (14), octadecyl ferulate (15), (+)‐syringaresinol (16), β‐sitosteryl‐D‐glucoside (17), and a mixture of β‐sitosterol (18) and stigmasterol (19), were isolated from the methanolic extracts of the roots of Euchresta formosana. The structures of these compounds were established by means of spectral analysis.
Intermolecular Interactions in Aqueous Dimethyl Sulphoxide and Acetic Acid Probed by High‐Pressure FTIR
Authors: Feng Chun‐Min , Kao Hsiang‐En , Su Chih‐Chia , Jiang Jyh‐Chiang , Lin Sheng Hsien , Chang Hai‐Chou
Published: May 2015

The infrared spectra of DMSO/D2O and CH3COOD/D2O were measured under various concentrations and pressure. The frequencies of the C‐H stretching vibration bands for DMSO/D2O mixtures increase with increasing the mole fraction of D2O, implying the contraction of the C‐H bonds. As the pressure was elevated to 1.5 GPa, the C‐H vibrations of DMSO/D2O were altered into four bands at ∼2927 cm−1, ∼2941 cm−1, ∼3007 cm−1, and ∼3025 cm−1. Further concentration‐dependent studies indicated that the spectral features at ∼2941 cm−1 and ∼3036 cm−1 arise from pressure‐induced C‐H—O hydrogen bonding between C‐H in DMSO and oxygen atom in D2O. Ab initio calculations were performed, while the calculated results are consistent with the interpretations based on the high‐pressure infrared experiments. Analogous to DMSO/D2O, the pressure‐dependent studies on CH3COOD/D2O mixtures provide the evidence of the C‐H—O hydrogen bonding as the pressure was elevated.
Fiber‐Optic Chemical Sensors: A General Review
Authors: Yang Jyisy , Lee Chung‐Jay , Wei Cheng‐Huang
Published: May 2015

Fiber‐optic sensors provide a simple and fast way in detection of interested molecules in variety of sample matrices. To accelerate the progress in this field, the basic sensing principles and current technologies of both extrinsic and intrinsic types of fiber‐optic sensors were described in this article. In the intrinsic fiber‐optic sensors, evanescent wave absorption spectroscopic method and fluorescence spectroscopic method based on evanescent wave excitation were introduced. In the extrinsic fiber‐optic sensors, two major types of sensors including fluorescence spectroscopic method and Raman spectroscopic method were described. The complementary chemical information and unique advantages of different sensors were described.
Electronic Angular Momentum Polarizations of Atomic Fragments in Diatomic Photodissociations: Correlations between Electronic States in the Molecular and the Asymptotic Regions
Authors: Chen Kuo‐Mei
Published: May 2015

To understand electronic angular momentum polarization phenomena of atomic photofragments in diatomic photodissociations, Wigner‐Witmer correlation rules should be augmented to treat these problems quantitatively. The essential step to achieve this goal is to find the transformation relationships between basis functions of Hund's coupling cases (a) (or (b)) and (c). Because the partition of a united electronic configuration into two separated electronic configurations is undertaken, in general no analytical transformation can be established. To illustrate the present scheme in acquiring the transformation relationships, the direct photodissociation of O2(B3Σ−u) into O(1D) + O(3P) is explicitly considered. The electronic angular momentum polarization of oxygen atoms in |1D, J = 2, MJ = 0〉 observed in the recent experiment on O2 photodissociation can be rationalized by this quantitative correlation rule.
Green's Function and Eigenvalue Representations of Time Lag for Membrane Permeation Transport
Authors: Chen Jenn‐Shing , Chang Wen‐Yih
Published: May 2015

Modeling membrane permeation transport by particles undergoing random walk over a one‐dimensional lattice leads to a master equation, which describes the time dependence of particle concentration. With the stipulated conditions appropriate for absorptive permeation, the master equation is then solved in the Laplace domain to find the flux into the receiver, which in turn is used to formulate the time lag, tL. It turns out tL can be represented by trace(A−1), where A is the transition matrix associated with the master equation. An analog to this representation for the continuous coordinate space is \documentclass{article}\pagestyle{empty}\begin{document}$ {\rm t}_{\rm L} = \int\limits_{\rm 0}^{\rm h} {{\rm G}\left({{\rm x,x}} \right){\rm dx}} $\end{document}, where G(x, x) is the Green's function associated with the steady‐state diffusion equation with zero value at both boundaries 0 and h, and the source and observation points coinciding at x (0 < x < h). We have also provided a rigorous proof for this new Green's function representation of time lag. A bonus from the latter is that the time lag can be calculated \documentclass{article}\pagestyle{empty}\begin{document}$ {\rm t}_{\rm L} = \sum\limits_{\rm n} {\frac{1}{{{\rm \lambda }_{\rm n} }}} $\end{document}, where λn is the eigenvalue of the transmission matrix. The directional symmetry of the time lag is easy to be interpreted on the basis of Green's function or eigenvalues representations.
Cation Driven Charge Transfer in (Co, Fe) Prussian Blues
Authors: Sheu Hwo‐Shuenn , Jen Shih‐Hui , Kang Ting‐Wei , Jang Ling‐Yun , Lee Jyh‐Fu
Published: May 2015

The charge transfer between Cobalt and Iron ions in a series of (Co, Fe) Prussian blues has been investigated by synchrotron X‐ray absorption spectroscopy and powder diffraction. (Co, Fe) Prussian blues, AxCoy[Fe(CN)6]‐nH2O where A = Li, Na, K, Rb and Cs, were prepared by dropwise mixing method. X‐ray absorption near edge spectra showed that cobalt was in a higher oxidation state when the interstitial alkali cation changed from Li, Na, to K, Rb, Cs. At the same time, the valence of Fe shifted from 3+ to 2+. The cation driven charge transfer ability follows the order of Li ≈ Na < K < Rb ≈ Cs. A similar trend was also found when the KCl concentration was increased during the synthesis of K‐containing Prussian blue. The higher the concentration of KCl, the more Fe2+‐CN‐Co3+ fragment in the (Co, Fe) Prussian blue, and hence the higher efficiency for photo‐induced magnetization. The Co‐N distance in Prussian blue became shorter, about 0.15 Å in Co2+ salt compared to Co3+ salt, and the unit cell dimension was reduced about 0.3 Å as well.
Geneses of Cobaltic Oxide
Authors: Huang Jin‐Fa , Hung Aina , Wang Chen‐Bin , Yeh Chuin‐Tih
Published: May 2015

A sample of cobalt oxide with cobalt ions in a highly oxidative state, p‐Co2O3, was prepared from Co(NO3)2(aq) through a precipitation by NaOH and an oxidation by H2O2. The prepared p‐Co2O3 was characterized as a nonstoichiometric sample with a chemical formula of Co3+0.96Co4+0.04O2−1.52‐0.6H2O, by combined techniques of the thermogravimetry (TG) and temperature‐programmed reduction (TPR). Stoichiometric samples of Co2O3‐H2O, Co3O4 and CoO were fabricated from the p‐CO2O3 by controlled hydrogen reduction in TPR to 420 K and thermal decompositions at 670 and 1170 K, respectively. The stoichiometric cobalt oxides have been subsequently used as standard samples to pursue their reducibility in hydrogen and their structures with XRD and IR spectrum. The refined cobaltic oxide was characterized as a monohydrated oxide of hexagonal crystal.
Structure, Magnetic Properties, Mössbauer and Catalase‐like Activity of Spin Crossover Iron(III) Complexes with Salicylaldimine Ligands
Authors: Wang Meichen , Lee Gene‐Hsiang , Wang Yu , Dong Teng‐Yuang , Wei Ho‐Hsiang
Published: May 2015

The preparation and characterization of three new spin‐crossover ferric complexes with the composition [Fe(5‐Br‐Salmeen)2]ClO4 (1), [Fe(5‐Br‐SalEen)2]PF6.CH2Cl2 (2), and [Fe(3‐OCH3‐Salpen)2]PF6 (3), where substituted Salmeen, SalEen, and Salpen result from the Schiff‐base condensation of substituted salicylaldehyde with N‐methylethylenediamine, N‐ethylethylenediamine, and N‐methylpropylenediamine, respectively. The structural determinations reveal that complexes 1–3 cations possess the same general structure with the N4O2 donor atom set from two tridentate ligands forming a distorted octahedron about the Fe(III) ion. Complexes 1–3 have been shown by variable‐temperature magnetic susceptibility (2–300 K) and 57Fe Mössbauer spectroscopy to be (low‐spin, S = 1/2) ↔ (high‐spin, S = 5/2) spin‐equilibrium compounds in the solid state. The H2O2 disproportionation of complexes 1–3 in methanol at 25 °C show the rate law of kobs[H2O2] [complex].
Tetrachlorophenylporphyrinato Manganese(III) Acetate as a New Ionophore for a Coated Triiodide Ion‐Selective Electrode
Authors: Farhadi Khalil , Bonab Hossein Sheikhloei , Maleki Ramin , Shamsipur Mojtaba , Shargi Hashem
Published: May 2015

A novel triiodide sensor based on (tetrachlorophenylporphyrinato) manganese(III) acetate is described. The electrode is prepared by incorporating the ionophores into plasticized PVC membrane, which is directly coated on the surface of a graphite electrode. The resulting electrode has a linear dynamic range between 1.0 × 10−1 and 7.9 ×10−6 M with a near‐Nernstian slope of −66.5 ± 1.0 mV per decade and a detection limit of 6.0 × 10−6 M. The influences of lipophilic additives on the response properties of the electrode were investigated. The proposed sensor revealed high selectivity for triiodide over a wide variety of other anions and could be used in a pH range 2–9. The electrode can be used for at least 3 months without any considerable divergence in potential. It was applied as indicator electrode in potentiometric titration of ascorbic acid and triiodide ions.