bluuebunny/crossref_metadata_2025 huggingface dataset:
Polarographic Study of Thallium(I) Complexes with Large Crown Ethers in Binary Acetonitrile‐Water Mixtures
Authors: Farhadi Khalil , Shamsipur Mojtaba
Published: May 2015

The complexation reactions between the Tl+ ion and large crown ethers dibenzo‐30‐crown‐10 (DB30C10), dibenzo‐27‐crown‐9 (DB27C9), dibenzo‐24‐crown‐8 (DB24C8) and dibenzo‐21‐crown‐7 (DB21C7) were studied in different acetonitrile‐water mixtures at 25°C using an a.c. polarographic technique. The stoichiometry and stability of the complexes were determined by monitoring the shift in peak potential of the polarographic waves of the metal ion against the crown concentration. In all solvent mixtures used, the stability of the resulting 1:1 complexes was found to vary in the order DC24C8 » DB30C10 > DB21C7 > DB27C9 > DB24C8. There is an inverse relationship between the complex formation constants and the amount of water in the mixed solvent. In all cases, a linear relation was observed between log Kf and the mole fraction of acetonitrile in its mixtures with water.
Simulation of the Collisional Cooling Effect in a Quadrupole Ion Trap Mass Spectrometer
Authors: Wu Hui‐Fen , Chen Li‐Wei , Lin Ya‐Ping
Published: May 2015

Examination of the collisional cooling effect of the buffer gases on ion trapping and detection in an ion trap mass spectrometer has been undertaken by the SIMION 3D program. Computation for the kinetic energy of ions under various conditions was used to account for the effects of collisional cooling of ions. Several parameters that may affect the collisional cooling effects of ions are evaluated including the existence and the variation of pressure of the buffer gas; the temperature of the ion trap; the size of the inner radius of the ion trap electrodes; the mass to charge ratio of ions; the alternative buffer gases and the qz. values which establish the ion trap trapping environment.
The Characterization of a New Reagent and Its Application in Determining Cu2+
Authors: Ma Donglan , Huang Yunrui , Xia Dongsheng , Wang Yulu
Published: May 2015

The study of the reaction of the new spectrophotometric reagent with Cu2+, N‐allyl‐N′‐(sodium p‐aminobenzenesulfonate)‐thiourea(ASAT)'s preparation and its characteristics are described. It was found that this reagent can react with some ions having characteristic phenomena, and, also determine a microamount of copper (ϵ303 nm = 2.39 × 105 L·mol−1·cm−1) in aqueous solution. The method's sensitivity and selectivity are good. The new methods are simple and convenient and can provide satisfactory results on samples.
Phase Transfer Catalyzed Method to Prepare Symmetrical Azobenzenes from Anilines
Authors: Wang Xiao‐Yang , Wang Yu‐Lu , Wang Cai‐Lan , Li Jian‐Ping , Wang Hong , Zhang Zi‐Yi
Published: May 2015

Using free radical 4‐hydroxy‐2,2,6,6‐tetramethyl‐1‐piperidinyloxyl as catalyst, the phase transfer catalyzed method of oxidation of anilines to symmetrical azobenzenes with a saturated solution of potassium ferricyanide in 2N aqueous potassium hydroxide and dichloromethane is described for the first time. The reaction has an intimate relation with Hammett substituent constants. This report offers an efficient and rapid method to prepare azobenzenes, and a possible mechanism is also suggested.
Formal Syntheses of (±)‐Methylenomycins A and B
Authors: Hong Fang‐Tsao , Lee Kung‐Shing , Liao Chun‐Chen
Published: May 2015

The syntheses of methyl ester of (±)‐desepoxy‐4,5‐didehydromethylenomycin A (4) and 2,3‐dimethyl‐5‐methoxycarbonyl‐2‐cyclopentenone (5) were accomplished from a common starting material, 2,3‐dimethyl‐4‐methoxyphenol (8), in only four and two steps in 35% and 53% overall yields, respectively. Photochemical rearrangements of masked p‐benzoquinones in methanol are the key steps.
Microwave Accelerated Cycloaddition Reactions of Nitrile Oxides and Allylic Alcohols
Authors: Lu Ta‐Jung , Tzeng Gwo‐Ming
Published: May 2015

The application of microwaves in promoting the cycloaddition reactions of allyl alcohols with nitrile oxides using a domestic microwave oven and a focused monomode microwave reactor have demonstrated that not only was the reaction time substantially reduced, but also the reaction yields were significantly improved over the conventional stirred reactions. Microwave irradiation alters the regioselectivity of the cycloaddition reaction which favors the non‐hydrogen‐bond directed cycloadduct, isoxazoline 4.
Molecular Nonlinear Optical Properties of Acceptors Substituted 2,2′‐Bipyridine and 1,10‐Phenathroline Complexes of Nickel Dithiolate
Authors: Chen Chin‐Ti , Lin Tzu‐Yao Jeremy , Chen Chiung‐Hsueh , Lin Kuan‐Jiuh
Published: May 2015

Linear and nonlinear optical properties of two new nickel(diimine)(dithiolate) complexes, nickel(4,4′‐dinitro2,2′‐bipyridyl)(tfd), Ni(NO2bipy)(tfd), (tfd = 1,2‐trifluoromethylethene‐1,2‐dithiolate) and nickel(4,7‐diphenyl‐1,10‐phenathroline)(tfd), Ni(dpphen)(tfd) are reported. Ni(NO2bipy)(tfd) has a potent electronic acceptor substituted on the diimine ligand and exhibits an enhanced molecular first hyperpolarizability (β0 = −31 × 10−30 esu), which is more than three times greater than that (β0 = −10 × 10−30 esu) of Ni(dpphen)(tfd). Ni(NO2bipy)(tfd) also possesses the longest absorption wavelength, the largest solvatochromic shift, and one of the largest dipole moment changes (‐16 debye from ground to excited state) among nickel(diimine)(dithiolate) complexes. Crystal X‐ray structure of Ni(NO2bipy)(tfd) is used to compared the π‐bonding structure of central (N=C‐C=N)Ni(S‐C=C‐S) unit with that of previously known nickel(4,4′‐bis(butyloxycarbonyl)‐2,2′‐bipyridyl)(tfd), Ni(CO2Bubipy)(tfd).
Coprecipitation Synthesis of a Superconductor via Multi‐Precipitants
Authors: Chen Yung‐Fang , Sheen Shyang‐Roeng
Published: May 2015

A precipitation process has been developed to prepare precursor powders, which can be calcined and sintered to form high‐Tc superconductors such as YBa2Cu3Oy. Precursor powders are prepared using a mixed‐precipitants system in which a solution contains precipitating anions such as hydroxide, oxinate and oxalate ions. A theoretical study on the conditions of mixed‐precipitants coprecipitation is performed. The solution pH of complete precipitation of the title system is extended and is maintained between 4.46 and 12.0. A series of experiments were conducted to confirm the as‐derived optimal condition. Finally, characterization of the properties of the YBa2Cu3Oy obtained after high temperature treatment is reported.
Palladium‐Catalyzed Chemoselective Intramolecular Cyclization of 2‐Bromoaryl Alkenenitriles
Authors: Deng Jui‐Hui , Tai Huo‐Mu , Yang Chau‐Chen
Published: May 2015

The chemoselectivity in the palladium‐catalyzed intramolecular cyclization of 2‐(o‐bromoaryl)‐alkenenitriles depends on the nature of α‐substitutents. 2‐(o‐Bromoanilino)alkenenitriles attacked the cyano group, followed by the cyano group transposition and hydrolysis, to give o‐(methylamino)benzonitrile. 2‐(o‐Bromobenzyl)alkenenitriles, 2‐(o‐bromophenylthio)alkenenitriles and 2‐(o‐bromophenoxy)‐alkenenitriles attacked the olefinic double bonds and led to l‐vinyl‐2‐indancecarbonitrile, 1,2,3,4‐tetrahydronaphthalene‐2‐carbonitriles, 3,4‐dihydro‐2H‐benzo[b]thiine‐2‐carbonitriles, and 3,4‐dihydro‐2H‐benzo[b]oxine‐2‐carbonitriles. A general mechanism for the palladium‐catalyzed arylations is proposed.
Nanocrystalline Tin‐Oxide Modified Electrodes and their Electrochemical Characterization
Authors: Wang Wen‐Ying , Wang Chong Mou
Published: May 2015

Nanocrystalline tin‐oxide particles were prepared as electrodes on the bases of ITO glass and AT‐cut quartz crystals (sputtered gold), respectively, and characterized for their electrochemical behavior. Experiments suggested that the SnO2 particles could induce an energy barrier to the redox reactions taking place on the electrode surface. When the amount of SnO2 exceeded ca. 10−7 mol cm−2, electrochemical activity demonstrated by the solution redox couples was entirely suppressed. Nevertheless, electrochemical impedance spectroscopic (EIS) measurements suggested that mutual communication between redox couples would still take place on the surface of SnO2. For instance, although the CV curves of Fe(CN)63‐/4‐ were completely blocked, the exchange current of Fe(CN)63‐/4‐ could still flow through the tin‐oxide modified electrode, increasing with its concentration up to 40 mM. The propagation of electrons in the SnO2 film was likely via a hopping mechanism. Electrochemical quartz microbalance (EQCM) measurements, in addition, suggested that a charge‐compensating cation (K+ or H+) uptake reaction may be induced as electrons were pumped to the Sn02 electrode, while, if electrons were removed, that could cause water desorption. Analysis based on the Frumkin adsorption isotherm showed the driving force behind the adsorption of water on SnO2 is about −2 kcal/mol. Nonetheless, the adsorbed water might face a competitive repulsion from acetonitrile when acetonitrile was used as the electrolyte medium.
Analysis of Synthetic Drugs in Chinese Medicine by High Performance Liquid Chromatography/Mass Spectrometry with In‐Source Collision Induced Dissociation
Authors: Song Yi , Cheng Hsing‐Ling , Her Guor‐Rong , Wen Kuo‐Ching
Published: May 2015

Sixteen chemical drugs, often found in adulterated Chinese medicine, were studied by high performance liquid chromatography/atmospheric ionization mass spectrometry. Under optimal conditions, three pairs of compounds were either coeluted or unresolved. The lack of chromatographic resolution and the lack of specificity in UV detection were overcome by a method based on high performance liquid chromatography/electrospray mass spectrometry. This method was capable of detecting the adulterants based on their retention times, molecular ions, and characteristic fragments resulting from in‐source collision induced dissociation.
Synthesis and Reactivity of 2‐(2,2‐Dicyano‐1‐methylvinyl)benzothiazole in Heterocyclic Synthesis: Convenient Route to Some Pyridazinone, Hydrazonoethyl, Thiophene, Phathalic Anhydride and Benzene Derivatives Incorporating a Benzothiazole Moiety
Authors: Selim Maghraby A. , Raslan Mohamed A. , Khalil Mohamed A. , Sayed Samia M.
Published: May 2015

A facile route to some pyridazinone, hydrazonoethyl, thiophene, phathalic anhydride and benzene derivatives incorporating a benzothiazole moiety is reported.
Bishordeninyl Terpene Alkaloids from Zanthoxylum Integrifoliolum
Authors: Liu Sian‐Ling , Tsai Ian‐Lih , Ishikawa Tsutomu , Harayama Takashi , Chen Ih‐Sheng
Published: May 2015

Examination of the leaves of Zanthoxylum integrifoliolum led to the isolation of a new bishordeninyl alkaloid, integramine, along with alfileramine, α‐allocryptopine, pseudoprotopine and (+)‐sesamin from the tertiary non‐phenolic base fraction. The structures of these compounds were elucidated by spectral evidence.
Optical Absorption of Long Range Electron Transfer Systems in Intense Fields
Authors: Okada Akira , Chernyak Vladimir , Mukamel Shaul
Published: May 2015

Effects of strong radiation field on long range electron transfer reactions and the crossover between the nonadiabatic and adiabatic limits are investigated. Dramatic variations of the absorption spectrum as a function of laser intensity were predicted in the nonadiabatic limit by Dakhnovskii, Lubchenko, and Coalson (Phys. Rev. Lett. 1996, 77, 2917). These results are extended by utilizing the interaction picture and Green function technique to calculate the spectrum in the crossover and the adiabatic regions. As the solvation timescale becomes slower, the multiphoton absorption is enhanced, and the dependence of the absorption spectrum on field intensity is supressed, eventually vanishing in the adiabatic limit.
Femtosecond Investigation of Photophysics of Intersystem Crossing in Terthiophene
Authors: Yang Ji‐Ping , Paa Wolfgang , Hotzel Mario , Rentsch Sabine
Published: May 2015

Photophysics of ultrafast intersystem crossing and triplet yield in 2,2′:5′,2″ ‐terthiophene (3T) was investigated in dependence of excitation wavelength by means of femtosecond time‐resolved absorption/emission spectroscopy. Triplet generation yield was monitored by using the product of maximum and width of the photoinduced triplet absorption band near 460 nm. We found that triplets were generated by two different processes: (i) the well‐known intersystem crossing from the lowest vibrational S1 state and (ii) ultrafast intersystem crossing from an intermediate state generated by photoexcitation. We discuss the probable formation mechanism and the lifetime of an intermediate state. The results suggest that this intermediate state is a nonplanar conformer within the S1 manifold; it seems to be responsible for the high effective triplet generation.
Excitation Energy‐Transfer in the LH2 Antenna of Photosynthetic Purple Bacteria via Excitonic B800 and B850 States
Authors: Linnanto Juha M. , Korppi‐Tommola Jouko E. I.
Published: May 2015

A newly developed CIEM method that uses a combination of semi‐empirical or ab‐initio configuration interaction methods and exciton theory to predict electronic energies, eigenstates, absorption and CD spectra of aggregated chromophoric systems with environmental interactions included is extended and used for estimation of excitation energy transfer rates. Excitonic energy levels of the two ring systems the B800 and the B850 of the light harvesting antenna LH2 of Rhodopseudomonas acidophila and the corresponding absorption spectrum were calculated by assuming inter‐ring interactions to be zero. Excitation energy transfer rates were calculated by using the Fermi Golden rule with the dipole ‐ dipole operator, the excitonic basis sets created by the CIEM method of the non‐interacting ring systems and a statistical variation of the elements of the exciton Hamiltonian to account for the inhomogenous broadening of the experimental spectrum. Energy transfer rates of from 300 fs to 450 fs within the B800 ring, from 450 fs to 800 fs from the B800 ring to the B850 ring, that are in good agreement with the experimentally observed rates, were obtained. The model predicts wavelength dependent energy transfer rates within the B800 band, with slower rates in the red end of the absorption. Energy transfer between two excitonic systems imply that observed rates depend on the spectral/temporal widths of the excitation and probe pulses. The model also predicts decreasing rates for low temperatures, as homogenous line widths become narrower at lower temperatures.
Spectral Holography and Spectral Nonlinear Optics of Ultrashort Pulses
Authors: Mazurenko Yuri T.
Published: May 2015

This paper reviews the principles of recording, reconstruction and nonlinear transformations of ultrashort light pulses, based on spatial spectral decomposition of light. Some applications of these methods for processing time‐dependent signals in the femtosecond to nanosecond range are also considered.
Generalised Master Equation for the Spin‐Boson Hamiltonian by the Projection Operator Technique
Authors: Cheche T. O. , Hayashi M. , Lin S. H.
Published: May 2015

Starting from the von Neuman equation of quantum theoretical dynamics, by using the projection operator technique, we write the generalised master equation (GME) of the reduced statistical operator. By using this technique we find a series expansion of the memory kernel which allows, in principle, a treatment of the higher orders of approximation. By keeping only the first term of this expansion, which corresponds to the second order of the perturbation treatment, GME is applied, in the Markov approximation, to the spin boson Hamiltonian to describe the dynamics of the relevant pseudo‐spin subsystem. In the secular and rotating wave approximations this dynamics is found to be described by the Bloch equations.
The Adsorbate Electron Affinity Dependence of Femtosecond Electron Dynamics at Dielectric/Metal Interfaces
Authors: Gaffney Kelly J. , Liu Simon H. , Miller Andre D. , Szymanski Paul , Harris Charles B.
Published: May 2015

The two photon photoemission technique has been utilized to investigate the adsorbate electron affinity dependence of interfacial electron transfer dynamics. The comparison of calculated and experimental results highlight a brief discussion of a dielectric continuum model. For the n‐heptane/Ag(111) and the benzene/Ag(111) interfaces, the model effectively reproduces experimental image potential state properties. The model fails to adequately describe the influence of anthracene adsorbates on image potential state lifetimes, as demonstrated by the experimental and theoretical results. The experimental n = 1 lifetime of 1200 femtoseconds and binding energy of −0.53 eV for the anthracene bilayer differ greatly from the calculated values of 40 femtoseconds and −1.4 eV.
Anharmonic Oscillator Approach to the Exciton‐Exciton Annihilation Dynamics in Molecular Aggregates
Authors: Renger T. , May V. , Sundström V. , Kühn O.
Published: May 2015

The dynamics of Frenkel excitons in aggregates of coupled electronic three‐level molecules in the presence of strong external fields is investigated. Particular emphasis is paid to the microscopic inclusion of exciton‐exciton annihilation. It appears as a combination of exciton fusion and internal conversion processes which are taken into account within perturbation theory. The influence of an environment on the exciton dynamics is treated by means of stochastic fluctuations of the electronic transition energies. A closed set of equations of motion is derived and it is shown how nonlinear optical spectra can be calculated nonperturbatively.
Importance of Acoustic Solvent Mode and Solute‐Solvent Radial Distribution Functions in Solvation Dynamics: Studied by RISM Theory
Authors: Nishiyama Katsura , Hirata Fumio , Okada Tadashi
Published: May 2015

We have applied the reference interaction‐site model (RISM) theory to explain our experiments on solvation dynamics of laser dyes in polar organic solvents by means of the transient hole‐burning and time‐resolved fluorescence spectroscopy [K. Nishiyama and T. Okada, J. Phys. Chem. A, 101 (1997)5729; 102 (1998) 9729]. The experiments show that the dynamic response function of the relaxation derived from the inhomogeneous spectral band‐width of the solute‐solvent system relaxes about an order of magnitude slower than that of average energy of the system. On the basis of our present theoretical prediction, we suggest that the relaxation dynamics of the spectral width might be mainly characterized by the solvent acoustic mode (translational motion) as well as the rearrangement of second plus further solvent shells.
Time‐Resolved Fluorescence Spectroscopy of Porphyrin J‐Aggregates Using Optical Kerr Gate Methods
Authors: Kano Hideaki , Kobayashi Takayoshi
Published: May 2015

We observed for the first time ultra‐fast relaxation process due to internal conversion from S2‐exciton to S1‐exciton in porphyrin J‐aggregates using the optical Kerr gate method. The S2 fluorescence shows sharp spectra with almost zero Stokes shift. The decay time is less than the instrumental function and cannot be time‐resolved by the Kerr gate method. The relaxation time of the S2‐exciton was also measured by pump‐probe spectroscopy with about 10 fs resolution, and the decay time, 130 ± 10 fs, was consistently obtained with that of the S2 fluorescence.
The Decomposition Reaction of 4‐Acetylsydnones Arylhydrazones
Authors: Kuo Wen‐Fa , Chiu Chun‐Yen , Lin I‐Tzu , Sheu Shu‐Ya , Lm Kao‐Hung , Yeh Mou‐Yung
Published: May 2015

The acidic decomposition of 4‐acetylsydnones arylhydrazones 2 results in the formation of 4‐arylhydrazo‐1,2‐pyrazolin‐5‐ones 3 and 4‐arylamino‐1,2,3‐triazoles 4, respectively. The reactions of 4‐acetylsydnones 1 with arylhydrazines 5 afford compounds 3 as the only products in the absence of solvent.
Synthesis and Structure Characterization of 2‐(Dimethylaminomethyl)pyrrolate and 2,5‐Bis(dimethylaminomethyl)pyrrolate Zirconium Complexes
Authors: Huang Jui‐Hsien , Kuo Pei‐Cheng , Lee Gene‐Hsiang , Peng Shie‐Ming
Published: May 2015

Tetrakis(diethylamido)zirconium reacts with 2‐(dimethylamino)methyl pyrrole (DMAMP) and 2,5‐[bis(dimethylamino)methyl]pyrrole (BDMAMP) to give Zr(NEt)2(DMAMP)2 1 and Zr(NEt)3(BDMAMP) 2, respectively. Both 1 and 2 have been characterized by 1H and 13C NMR spectroscopies and 1 has also been characterized by X‐ray crystallography. Complex 1 shows an agostic interaction between Zr and H(21A) in solid state that is not sustained in solution. Reacting 1 with 2 equivalents of trimethylsilyl chloride in toluene yields ZrCl2(DMAMP)2 3 in 75% yield which was characterized by 1H and 13C NMR spectroscopies.
Kinetics of 2‐Propanol Dehydration over Montmorillonite Clays and Pillared Montmorillonites
Authors: Cho Youg‐Gou , Ko An‐Nan
Published: May 2015

Metal ion exchanged montmorillonites (AlM & CrM) and metal oxide pillared montmorillonite (AlPM & CrPM) were prepared and characterized with XRD, FT‐IR, nitrogen adsorption and TPD of ammonia. The pillaring process results in a remarkable increase of interlayer distance, surface area and acid amount of the catalyst. However, increasing the calcined temperature causes reverse effects for the CrPM catalyst. The acid amount decreases in the order of CrPM200 < CrPM300 < AlPM500 < CrM < CrPM400 ≥ CrPM500 ≥ AlM. In the dehydration of 2‐propanol to propene, the reaction follows first order kinetics and the apparent rate constant is related to the catalyst acid amount. Compensation effect occurs in this reaction over the series of catalysts.
The Separation of Alanine Enatiomer Derivatives by the Proton‐Inhibition Method
Authors: Lee Sheau‐Long , Yang Chung‐Min , Shieh Kuan‐Jiunn , Liang Xinmiao , Li Hai‐Yan
Published: May 2015

Better peak shapes and complete separation of amino‐3,5‐dinitro derivatives by (S)‐N‐(2‐naphthyl)alanine derived chiral stationary phase (CSP) is achieved by adding a trace amount of acetic acid in the mobile phase. This method provides an indication of its broad applicability on direct separation of a series of amino‐containing enantiomers on CSP. In addition, the reversed elution order was obtained on its enatiomeric CSP.
Synthesis of ϵ‐Caprolactam from Cyclohexanone Oxime Using Zeolites Hβ, HZSM‐5, and Alumina Pillared Montmorillonite
Authors: Ouyang Kuang‐Hao , Chen Chih‐Wei , Ko An‐Nan
Published: May 2015

The Beckmann rearrangement of cyclohexanone oxime (CHO) to ϵ‐caprolactam (ϵ‐C) was studied in a plug flow reactor at 300–400°C under atmospheric pressure by using Hβ, ZSM‐5, and alumina pillared montmorillonite. With Hβ(X) Y zeolites, raising the SiO2/Al2O3 molar ratio (X) results in the enhancement of catalyst acid strength with concomitant decrease of the total acid amount. In creasing the calcination temperature (Y) causes remarkable diminution of catalyst surface area, acid strength, and acid amount. A similar trend was found for AlPMY catalysts. In there action of CHO, the initial catalytic activity correlates well with the total acid amount of various catalysts except for Hβ(10) Y (Y > 600°C). The reaction proceeds on both Brönsted and Lewis acid sites and the catalyst deactivation most likely occurs at the strong Brönsted acid sites. The effect of solvents in the feed on the catalytic results was also investigated; it was found that polar solvents such as ethanol or n‐butanol give high ϵ‐C yield and longer catalyst life time. In the reaction of CHO/C2H5OH over Hβ(10)800 at 400°C and W/F 74.6 gh/mol, the CHO conversion and ϵ‐C yield remain 100% and 92%, respectively, for at least 20 h time‐on‐stream. The reaction paths and the mechanism for ϵ‐C formation are proposed.
A Conformational Study of Cyclohexane‐1,3,5‐tricarbonitrile Derivatives
Authors: Chuang Tsung‐Hsun , Fang Jim‐Min
Published: May 2015

Cyclohexane‐1,3,5‐tricarbonitrile reached equilibrium having 1,3‐cis‐1,5‐cis and 1,3‐cis‐1,5‐trans isomers in a ratio of 3:7. The cis, cis‐isomer preferred the conformation with three equatorial cyano groups, where as the cis, trans‐isomer displayed two cyano groups on equatorial positions and another cyano group on axial position. Condensation of cis, cis‐cyclohexane‐1,3,5‐tricarbonitrile with L‐(S)‐valinol by the catalysis of ZnCl2 in refluxing 1,2‐dichlorobenzene afforded two isomeric cyclohexane‐1,3,5‐trioxazolines in favor of the 1,3‐cis‐1,5‐trans isomer. Metalation of cis, cis‐cyclohexane‐1,3,5‐tricarbonitrile, followed by alkylations with dimethyl sulfate, benzyl bromide or allyl bromide, gave the cor responding trialkylation products with predominance of 1,3‐cis‐1,5‐trans isomers. The cis, trans‐isomer showed two cyano groups on axial positions and another cyano group on equatorial position, where as the cis, cis‐isomer exhibited three axial cyano groups. Treatment of trimethyl cis, cis‐cyclohexane‐1,3,5‐tricarboxylate with lithium diisopropylamide and dimethyl sulfate afforded mainly the trimethyl ester of Kemp's triacid, which showed three axial carboxylate groups. Two competitive factors, i.e. the steric effect of in coming electrophiles and the dipole‐dipole inter actions of the cyano or carboxylate groups, might inter play to give different stereoselectivities in these reaction systems.
Exploration of an Efficient Method for Optical Resolution of Etodolac
Authors: Chou Shan‐Yen , Tseng Chin‐Lu , Chang Lien‐Shange
Published: May 2015

The exploration of an efficient method for resolving etodolac using either L‐cinchonidinium salt or chiral isopinocamphenol diastereomeric esters is described herein. Furthermore, racemization mechanism of chiral etodolac is rationalized in terms of an isotope labeling experiment.
Chemical Constituents from Strychnos Cathayensis
Authors: Cheng Ming‐Jen , Tsai Ian‐Lih , Chen Ih‐Sheng
Published: May 2015

Secostrychnosin (1), a new secoiridoid, as well as seven compounds never before isolated from nature: 4‐tert‐butyl‐2‐oxazolidinone (2), 3‐acetoxyindole (3), indole‐2‐carboxylic acid (4), benzocaine (5), 3‐acetylindole (6), butylparaben (7) and 2‐hydroxy‐3‐methoxybenzaldehyde (8), together with fifty other known compounds, have been isolated from the stem of Strychnos cathayensis. These compounds include twenty‐three alkaloids, twelve benzenoids, four steroids, three flavonoids, three iridoids, two triterpenoids, two secoiridoids, two fatty acids, one lignan, one acetophenone, one coumarin, one chromane, one tetraterpenoid, one tannin, and one organic acid. The structures of these compounds were determined by means of spectralanalyses.
An Efficient Synthetic Strategy for Introduction of C3‐C4 Double Bond into Eudesmane Skeleton: First Total Synthesis of (+)‐Chrysanthemol
Authors: Chen Yonggang , Zhou Gang , Xiong Zhaoming , Liu Lijun , Li Yulin
Published: May 2015

The first enantioselective synthesis of (+)‐chrysanthemol 1 was carried out starting from (+)‐dihydrocarvone in ten steps. In our studies, a facile synthetic strategy has been developed for introduction of C3‐C4 double bond into a eudesmane skeleton.
Product Imaging Studies of Photodissociation and Bimolecular Reaction Dynamics
Authors: Houston Paul L. , Cosofret Bogdan R. , Dixit Amitaviram , Dylewski Scott M. , Geiser Joseph D. , Mueller Julie A. , Wilson Ruth J. , Pisano Patrick J. , Westley Michael S. , Lorenz K. Thomas , Chandler David W.
Published: May 2015

This paper briefly reviews recent progress in product imaging studies of photodissociation and bimolecularreaction dynamics.

The SO2 + hv → SO(3Σ−) + O(3P2) channel in the ultraviolet photodissociation of sulfur dioxide at photolysis wave lengths between 202 and 207 nm has been studied using resonance‐enhanced multiphoton ionization with time‐of‐flight product imaging. These imaging experiments allowed the determination of the vibrational populations of the SO(3Σ−) fragment at several wave lengths. A change in the vibrational populations occurs from a distribution where most of the population is inv = 0 for wave lengths shorter than 203.0 nm to one where the population is more evenly distributed for longer wavelength dissociation. The changes in the internal energy distribution are attributed to participation of two different predissociation mechanisms. Our data suggest that the predissociation mechanism below 203.0 nm involves an avoided crossing with the repulsive singlet state.1A1.

The O3(X 1A1) +hv → 0(2p3PJ) + O2(X3Σg−) product channel in the UV photodissociation of ozone has been investigated at photolysis wave lengths of 226, 230, 233, 234, 240, and 266 nm. At 226, 230, 233, 234, and 240 nm, the yield of the O2 product in vibrational states greater than or equal to 26 was 11.8 ± 1.9%, 11.5 ± 1.2%, 8.2 ± 2.0, 4.7 ± 1.8, and 0.6 ± 0.1%, respectively.

Two‐dimensional ion counting product imaging has also been used to determine the bond energy for the dissociation of jet‐cooled O3 into O(1D) + O2(1Δ). The bond dissociation energy into O(1D) + O2(1Δ) was found to be 386.59 ± 0.04 kJ/mol. The standard heat of formation of O3 is calculated to be −144.31 ± 0.14 kJ/mol.

State‐selective differential cross sections for rotationally in elastic scattering of NO (Ji = 0.5, 1.5, F1 → Jf = 2.5–12.5, F1 and Jf=1.5–9.5, F2) from He and D2 measured by crossed molecular beam ion imaging are reported. The images typically exhibit a single broad rotational rain bow maximum that shifts from the forward to the back ward scattering direction with in creasing ΔJ. The angle of the rain bow maximum was lower at a given ΔJ for D2 than for He as a collision partner. At a collision energy of ∼500 cm−1, primarily the repulsive part of the potential surface is probed, which can be modeled with a 2‐D hard ellipse potential. This model for rotationally in elastic scattering is shown to qualitatively match the experimental differential cross sections. A more advanced CEPAPES for NO + He does not give substantially better agreement with the experiment.
Control of Photodissociation by Alignment, Bleaching and Optical Phase
Authors: Kawasaki Masahiro
Published: May 2015

We have demonstrated alignment of neutral molecules by nonresonant IR laser pulse, bleaching of electronically excited states by resonant IR laser pulse and photoabsorption control of ground state molecules by phase of incident light. The electric field of a pulsed laser is used for alignment that is demonstrated by measurement of the control of the anisotropy of photo fragments generated by polarized light. The angular distribution of I(2P3/2) atoms from the photodissociation of CH3I at 304 nm was measured with alignment by the 1.06 μm laser pulse excitation:

By the alignment, the photodissociation branching ratio of Cl(2P3/2) and Cl*(2P1/2) was controlled in the photodissociation of Cl2 at 404 nm. The 1.06 μm laser pulse excitation of the photoprepared OCS at 230 nm bleaches the formation of CO(X1Σ+, J) + S(1D) and induces a new excitation pathway by an upconversion process:

The phenomenon of interference of the amplitude for absorption of one photon of frequency 3 ω (201 nm) and the amplitude for absorption of three photons of frequency ω (603 nm) was successfully applied to ammonia, alkylamines, cyclooctatetraene and 1,1‐dimethylhydrazine.
New Insight into Exchange Energy of Covalent Chemical Bonds
Authors: Tang K. T. , Toennies J. P. , Yiu C. L.
Published: May 2015

The exchange energy for the H2 molecule is calculated for a wide range of inter nuclear distance R extending down to R = 0.5 a0 using the surface integral method. This method accounts for the physical exchange of the two electrons between the two nuclei. The good agreement of the present results with the standard Heitler‐London calculation demonstrates that the exchange energy can in deed be described in terms of electrons hop ping back and forth between the nuclei, an interpretation which has been frequently criticized in the past.
Hydrogen‐rare Gas Interactions and Raman Line Shapes
Authors: Waldron Levi , Liu Wing‐Ki
Published: May 2015

Employing the recent XC(fit) intermolecular potential for H2‐Ar, we have presented the results of the spectral parameters for the D2‐Ar Raman Q1 branch, obtained from quantum mechanical close‐coupled calculations. While the theoretical line shifts of the polarized Raman spectra were found to agree with experiments, the corresponding widths were smaller than the measured values by as much as 56%. We observed that the shifts and the widths depend on the vibrational dependence of the potential in their own separate ways, and our results suggested that the anisotropic vibrational dependence of the XC(fit) potential requires improvement, in conjunction with further fine‐tuning of the isotropic part. Even though there is no experimental data for comparison, we have computed the line‐mixing parameters of the polarized Raman Q1 branch, as well as the depolarized line widths and shifts for the Q1(j) lines. These results showed the same trends as the corresponding ones for D2‐He.
Direct Measurement of a Beam Force Exerted to a Foil with a Laser Displacement Meter
Authors: Katayama Ichiro , Jeong Sun‐Chan , Tsuchida Hidetsugu , Ogawa Hidemi , Sakamoto Naoki , Itoh Akio
Published: May 2015

The interaction of a beam with a target foil is studied using a torsion balance. The change in equilibrium angle of the target frame due to momentum transfer of the projectile was measured by a laser displacement meter. The thick foil result can be interpreted in a straight forward way. On the other hand, the thin foil result shows that the momentum transfer to the tar get is 71 +/‐ 10% of that expected from energy loss of a projectile.
Density Functional Theory with Optimized Effective Potential: An Application to Hollow Atoms in the Bulk of Metallic Materials
Authors: Tong Xiao‐Min , Kato Daiji , Watanabe Tsutomu , Shimizu Hiroshi , Yamada Chikashi , Ohtani Shunsuke
Published: May 2015

The local spin‐density functional theory with an optimized effective potential and self‐interaction correction is used to study the energy structure of hollow atoms or ions in the bulk of metallic materials. The energy structure of conduction electrons in the bulk of metallic material is treated by the jellium model. Based on this method, we have studied the emit ted x‐ray spectra of Arq+ hollow atoms and ions in the bulk of Ag as well as in the vacuum. By comparing the energy spectra of Arq+ hollow atoms or ions in the vacuum and in the bulk of Ag, we can illustrate the conduction electron screening effect. Our calculated x‐ray spectra of Arq+ hollow atoms or ions in the bulk of Ag is in reasonable agreement with the experiment.
Single and Multiple Ionization of Atoms by Electron Impact
Authors: Golecki Philip , Klar Hubert
Published: May 2015

We report progress achieved during decades on direct single and multiple ionization of simple atoms by electron collsion. In particular we investigate total cross sections from thresh old to high energies. We show that all experimental data compare favorably with Wannier thresh old theory. A better understanding of the ionization process one gets from the analysis of multiply differential cross sections. To this end we discuss (e, 2e) and (e, 3e) events.
Variational Calculation of the Energy for Helium‐like Ground State from Z = 2 to 5
Authors: Wang Zhi‐Wen , Guan Xiao‐Xu
Published: May 2015

The non‐relativistic energies of the ground states in the helium‐like systems from Z = 2 to 5 are calculated by using three different basis functions, the Slater‐type, the ordered coordinates and the modified angular wave functions in which the angular variational parameters are included. In calculations with the latter two types of basis functions, we only used 168 terms in eight l components. The best value of energy for neutral helium atom in this work is obtained by using the modified angular wave functions. It is determined to be −2.9037161 a.u., which is about 0.00017 a.u. lower than that obtained with the 221‐term Slater‐type expansions. In cases of the helium‐like ions from Z = 3 to 5, the comparison of our calculated results using these three types of basis functions indicates that the results obtained with the modified angular wave functions are better than those with the other two types of basis functions. The convergence pattern in energy with the increasing number of terms in the angular partial wave functions is also analyzed.
X‐ray Spectroscopy of Highly Charged Ions at the Tokyo EBIT
Authors: Nakamura Nobuyuki , Kato Daiji , Nakahara Tetsuro , Ohtani Shunsuke
Published: May 2015

Recent results and experimental plans in X‐ray spectroscopic studies of highly charged ions at the Tokyo EBIT (Electron Beam Ion Trap) are presented. We have been using a flat crystal spectrometer to observe X‐ray transitions in the energy range of 3–10 ke V. It has been used to investigate the strong configuration mixing in neonlike ions, the electron‐impact excitation of highly charged ions, the polarization of Ly‐α in hydrogenlike Ti21+, and so on. A Johansson type of spectrometer has been constructed to observe X‐ray transitions in the higher energy range, 10–30 keV. It will be used for high‐resolution spectroscopy of the Lyman series in hydrogenlike medium‐Z ions. In particular, an inter comparison method between Ly‐α of In48+and Ly‐β of Rh44+ is proposed to measure the 1s Lamb shift precisely. It will provide a precise test of the QED theory in the strong field regime.
Cavity Ringdown Spectroscopy: New Approaches and Out Comes
Authors: He Yabai , Orr Brian J.
Published: May 2015

Cavity ringdown (CRD) absorption spectroscopy provides high sensitivity and photometric precision in the measurement of weak optical absorption spectra. We report several innovations in CRD technique involving either pulsed or continuous‐wave (cw) tunable coherent sources. In the former case, we use narrowband, injection‐seeded optical parametric oscillator (OPO) devices based on quasi phase‐matched nonlinear‐optical media and a novel intensity‐dip cavity control scheme; one such pulsed OPO is pumped by a compact, in expensive multimode laser but still delivers single‐mode OPO signal output. The latter area concerns cw‐CRD spectroscopy with a single‐mode tunable diode laser (TDL) and a rapidly swept ringdown cavity, most recently enhanced by a novel optical heterodyne approach that yields a noise‐limited absorption sensitivity of 3 × 10−9 cm−1. Such pulsed and cw CRD methods are used to record weak rovibrational spectra of carbon dioxide gas (CO2) with high resolution in the 1.5‐μm near‐infrared region. Emphasis is on high‐performance spectroscopic systems with relatively simple, in expensive, compact instrumentation.
Synthesis, Crystal Structure and Magnetic Properties of Zinc (II) Chloride Complexes with Pyridyl‐Substituted Nitronyl Nitroxides
Authors: Lee Chin‐Jhan , Wei Ho‐Hsiang , Lee Gene‐Hsiang , Wang Yu
Published: May 2015

ZnCl2(NIT‐pPy) 1, (NIT‐pPy = 2‐(4‐pyridyl)‐4,4,5,5‐tetramethyl‐4,5‐dihydro‐1H‐imidazolyl‐1‐oxyl‐3‐oxide) crystallizes in the orthorhombic space group Pnn2 with the cell parameters a = 9.4083(9), b = 39.686(3), c = 7.4417(14) Å. ZnCl2(NIT‐6M‐oPy) 2, (NIT‐6M‐oPy = 2‐(6‐methyl‐2‐pyridyl)‐4,4,5,5‐tetramethyl‐4,5‐dihydro‐1H‐imidazolyl‐1‐oxyl‐3‐oxide) crystallizes in the monoclinic space group Pn with a = 7.377(2), b = 19.096(4), c = 11.853(2) Å, β = 95.65(3)°. The temperature dependence magnetic susceptibility of complex 1 revealed an intermolecular ferromagnetic exchange interaction. A simple spin‐polarization model has been used to justify the observed ferromagnetic exchange interaction between the spins of the radical NO group in complex 2.
Synthesis of Thiadiazolinylpyrazolopyridine and Pyridopyrazolotriazine Derivatives
Authors: Attaby Fawzy A. , Elneairy Mohamed A. A. , Eldin Sanaa M. , El‐Louh Ali K. K.
Published: May 2015

3‐Diazotized aminopyrazolo[3,4‐b]pyridines 2a,b used as good synthons for the synthesis of 3‐thiadiazolinylpyrazolo[3,4‐b]pyridines 8a,b through their reactions with thiocyanatoacetophenone (6) and pyrido[2,3:3′,4′]pyrazolo[5,1‐c][1,2,4]triazines 5a‐d via their reactions with several active methylene containing reagents: 3a,b, 12, 16, 20, 23a‐d and 26a‐c. All the structures of the newly synthesized heterocyclic compounds were established by considering the data of IR,1H NMR and mass spectra in addition to the synthesis of most newly synthesized heterocyclic compounds via other routes.
A Theory of Coulomb Explosion of Molecules
Authors: Lin S. H. , Mishima K. , Hayashi M. , Chang A. H. H. , Yi J. , Mebel A. M.
Published: May 2015

In this paper, a theory of Coulomb explosion of molecules in intense laser fields based on the Auger effect will be presented. We first show how to calculate the rate of Auger process and then show that multiple ionization processes can be induced by the Auger effect alone or by the Auger effect followed by autoionization. For the case of molecules, multiple ionization is in general followed by dissociation.
Physico‐Chemical Properties of Nb/Ti Binary Oxides and their Photo‐Catalytic Activities
Authors: Tsai Shi‐Jane , Cheng Soofin
Published: May 2015

A series of binary Nb/Ti ox ides was prepared by co‐precipitation. Their structure and physico‐chemical properties in term of surface area, surface acidity, bandgap energy and life time of the radiation‐excited electron‐hole pair were examined. These properties were correlated to their catalytic activities in photodegradation of oxygenated organic pollutants in water. The organic pollutants under investigation were phenol, cyclohexanol and tetrahydrofuran (THF). The lab‐made titanium oxide and those doped with a small amount of Nb (molar ratio of Nb/(Nb+Ti) less than 20%) showed higher activities in degradation of the organic pollutants. However, the mineralization efficiencies were different for the three oxygenated organic pollutants. Nearly complete mineralization to form CO2 could be achieved in the degradation of phenol. For cyclohexanol, only ca. 50% selectivity of CO2 was obtained over all the catalysts. Similar low efficiency in complete mineralization was observed in the degradation of THF, but higher selectivity (ca. 65–75%) of CO2 could be obtained on the binary oxide with Nb content less than 4 molar %. In contrast, the binary Nb/Ti oxide with equal Nb and Ti molar content gave the poorest catalytic activity. The photocatalytic activity is generally correlated well to the life time of the radiation‐excited electron‐hole pairs. The contribution of surface acidity to the photocatalytic activity was only demonstrated on the niobia‐dominant oxide catalysts to ward THF. The photocatalytic activity was found to have no correlation with the crystal line structure, the bandgap energy, the surface area or the surface hydroxyl density.
Synthesis and Reactions of Highly Protected Mannosamines
Authors: Smeu Jia‐Cheng , Shaw Yeng‐Jeng , Luh Tien‐Yau
Published: May 2015

Highly protected mannosamine derivatives are synthesized from protected glucose derivatives having a free hydroxy group at C2 position. Indium‐mediated allylation of protected mannosamine derivatives is investigated.
Effect of Monomer Sequencing on the Mesophase Behavior of PDPS/PDMS Copolymer
Authors: Yang Mei‐Hui , Hwang Yeun‐Hsing , Liu Jiann Chang , Chou Chyan
Published: May 2015

Polydiphenylsiloxane‐co‐polydimethylsiloxane (PDPS/PDMS) statistical and reshuffled copolymers with different compositions have been synthesized and characterized. The phase behaviors of these copolymers are studied by differential scanning calorimetry (DSC) and polarized optical microscopy (POM). Critical compositions for the appearance of the thermal transitions were determined. The thermal transition properties, such as temperature and peak shape, were correlated to the structures of the copolymers. Effect of the monomer sequencing on the mesophase transition behaviors was examined.
Two New Sesquiterpenes and Two New Lignans from the Leaves of Juniperus Chinensis Var. Kaizuka
Authors: Lee Ching‐Kuo , Cheng Yu‐Shia
Published: May 2015

Two new sesquiterpenes, 8,9‐secocedrachinol (1), (+)‐1‐hydroxy‐1,3,5‐bisabolatrien‐10‐one (2) and two new lignans, (7R,8S)‐9′‐(β‐rhamnopyranosyl)‐3‐methoxy‐3′:7,4′:8‐diepoxyneolignan‐4,9‐diol (3), and (7S,8S)‐9′‐(β‐rhamnopyranosyl)‐3‐methoxy‐3′:7,4′:8‐diepoxyneolignan‐4,9‐diol (4), together with eleven known compounds, cedral, sesquichamaenol, caryophylleneoxide, humulenepoxide, benzoic acid benzylester, 4‐hydroxy‐3‐methoxycinnamic acid, 7‐hydroxy‐8‐(3‐methylbut‐2‐enyl)chromen‐2‐one, 2‐[4‐(3‐ hydroxy propyl)‐2‐methoxyphenoxy]propane‐1,3‐diol, luteolin, 3,4‐bis‐(4‐hydroxy‐3‐methoxybenzyl)dihydro‐ furan‐2‐one, and pluviatolide were isolated from the leaves of Juniperus chinensis var. kaizuka. The structures of these compounds were established on the basis of spectroscopic data.
Crown Ether Phase Transfer Catalysts for An Ionic Polymerization of Bisphenol A / 4,4′‐Dichlorodiphenyl Sulfone
Authors: Lue Lie‐Chuan , Shih Jeng‐Shong
Published: May 2015

Various crown ethers were prepared and applied as phase transfer catalysts for the an ionic copolymerization of bisphenol A and 4,4′‐dichlorodiphenyl sulfone monomers with alkali salts, e.g., NaNH2, NaOH and KOH, as initiators. The catalytic abilities of various crown ethers for the an ionic polymerization of bisphenol A / 4,4′‐dichlorodiphenyl sulfone were found to be in the order: 15‐crown‐5 ≅ monobenzo‐15‐crown‐5 > 18‐crown‐6 > Dicyclohexano‐18‐crown‐6 > Dibenzo‐18‐crown‐6 > 12‐crown‐4 with sodium amide (NaNH2) as initiator. Sodium amide was shown to be a better initiator than NaOH or KOH with monobenzo‐ 15‐crown‐5 as a catalyst. Effects of solvents and temperature on the crown ether catalytic polymerization were also investigated. Dimethyl sulfoxide (DMSO) exhibited much better for the polymerization than other organic solvents, e.g., toluene, p‐xylene, dimethyl formamide and dioxane. Higher polymerization was found at higher temperatures and about 100% yield of poly(bisphenol A / sulfone) was obtained at 125 °C in 3 hr. The molecular weight of poly(bisphenol A / sulfone) as a function of reaction time was determined with gel permeation chromatography. Concentration effects of crown ether on % yield and molecular weight of poly(bisphenol A / sulfone) were also investigated and discussed.
De Sign and Synthesis of 1,2,4‐Oxadiazole Derivatives as Non‐Steroidal 5α‐Reductase Inhibitors
Authors: Chang Chih‐Shiang , Kan Wai Ming , Chen Chiu‐Liang , Wang K. C. , Chern Ji‐Wang
Published: May 2015

The purpose of this study was to synthesize compounds in which the 1,2,4‐oxadiazole moiety replaced the amide bond of ONO3805 and to evaluate its 5α‐reductase inhibitory activity as a potential benign prostatic hyperplasia therapeutic target. Four 1,2,4‐oxadiazole derivatives, 1,2,8, and 20, were evaluated in vitro against 5α‐reductase of rat liver microsome. The prepared 1 and 2 possessed similar binding affinity (Ki) to that of ONO3805. Therefore, the use of 1,2,4‐oxadiazole ring as surrogate of the amide bond in ONO3805 has a successful result in this study. It leads not only to enhance chemical stability but also to maintain meaningful inhibitory activity. The butyric acid moiety of these inhibitors is considered to play an important role in mimicing the phosphoric acid portion of coenzyme‐NADPH in interacting with the active site of 5α‐reductase.
Triterpenoids from Rhaponticum Uniflorum
Authors: Zhang Yong‐Hong , Cheng Jie‐Kai , Yang Li , Cheng Dong‐Liang
Published: May 2015

The isolation and identification of twenty‐one components (including four new triterpenoid saponins and one new triterpenoid acid) from the root of Rhaponticum uniflorum (L.) DC. (Compositae) are described. Their structures were determined on the basis of spectral analysis and chemical trans formation. The new compounds were identified as 3‐O‐α‐L‐arabinopyranosyl‐urs‐12,18(19)‐dien‐28‐oic acid β‐D‐glucopyranosyl ester, 3β‐ hydroxyurs‐12,18(19)‐dien‐28‐oic acid β‐D‐glucopyranosyl ester, 3β‐hydroxyurs‐12,19(29)‐dien‐28‐oic acid β‐D‐glucopyranosylester, 3‐O‐α‐L‐arabinopyranosyl‐urs‐9(11),12‐dien‐28‐oic acid β‐D‐glucopyranosyl ester and 2 α,3 α, 19α,25‐tetrahydroxyurs‐12‐en‐23,28‐dioic acid.