bluuebunny/crossref_metadata_2025_split huggingface dataset:
Crystal Structures and Magnetic Properties of Charge‐Transfer Salts: Cobaltocenium Bis(cis 1,2‐diphenylethene‐1,2‐dithiolato)metalates (Metal = Ni, Pd, Pt)
Authors: Sheu Chou‐Fu , Lee Jung‐Si 
Published: May 2015

AbstractCharge‐transfer salts [Co(C5H5)2][M(dpt)2] (M = Ni and Pt; dpt = cis‐1,2‐diphenylethene‐1,2‐dithiolate) were synthesized and crystallographically characterized. [Co(C5H5)2][Ni(dpt)2] crystallizes in the monoclinic space group C2/c with a = 25, 607(3) Å, b = 9.4151(11) Å, c = 14.407(4) Å, β = 101.373(22)°, V = 3405.3(10) Å3 and Z = 4. [Co(C5H5)2][Pt(dpt)2] belongs to the triclinic space group \documentclass{article}\pagestyle{empty}\begin{document}$ {\rm P}\bar 1 $\end{document} with a = 9.4666(11) Å, b = 13.9869(12) Å, c = 14.2652(9) Å, α = 99.983(6)°, β = 90.034(7)°, γ = 109.751(7)°, V = 1747.2(3) Å3 and Z = 2. Both structures consist of ··· D+A−D+A−D+A− ··· linear chains with the local C5 axis of the eclipsed [Co(C5H5)2]+ cation parallel to the best MS4 plane of the [M(dpt)2]− anion. Magnetic susceptibility measurements show that χM T values of the complexes [Co(C5H5)2][M(dpt)2] (M = Ni, Pd, and Pt) remain nearly constant in the temperature range 15–300 K, but decrease rapidly with further decreasing of temperature, indicating weak antiferromagnetic interactions at low temperatures.
Polar Chemical Constituents from Phoebe formosana
Authors: Wang Perng‐Haur , Lee Shoei‐Sheng 
Published: May 2015

AbstractA chemical investigation on the H2O‐soluble constituents from the leaf of Phoebe formosana. led to the characterization often compounds including two C‐glycosylflavone — vitexin (1), isovitexin (2); six O‐glycosylflavonol — quercetin 3‐O‐galactoside (3), quercetin 3‐O‐α‐L‐arabinopyranoside (4), kaempferol 3‐O‐α‐L‐arabinofuranoside (5), kaempferol 3‐O‐α‐L‐rhamnoside (6), kaempferol 3‐O‐β‐D‐xylopyranoside (7); one dihydroflavonol ‐(+)‐dihydroquercetin (8) and two nucleosides ‐adenosine (9), and adenine (10). Their structures were determined on the basis of spectral analysis.
Interfacing ASE and HPLC for the Determination of PAH in Soil
Authors: Chen Chien Wen , Wang Yun Yuan , Wu Gaston J. C. 
Published: May 2015

AbstractA method was developed to couple an accelerated solvent extraction system (ASE) with high performance liquid chromatography (HPLC) for the analysis of PAH in soil samples. The resolution of HPLC is well maintained while the advantages of ASE, fast extraction, less solvent consumption and ease of operation, are well expressed. The precision and accuracy of this method are verified by a series of analyses of reference material, and the precision of retention from multiple injection indicates minimum loss of chromatographic resolution by the interface of this technique. Detection limits for the studied PAH range from 0.07 ng/Kg to 0.21 ng/Kg with a fluorescence detector.
Chemical Constituents of a Formosan Soft Coral Sinularia sp.
Authors: Sheu Jyh‐Horng , Chang Kuie‐Chi , Sung Ping‐Jyun , Duh Chang‐Yih , Shen Ya‐Ching 
Published: May 2015

AbstractA new marine sterol 7β‐hydroperoxy‐24‐methylenecholesterol (1) along with five known compounds sarcophytol A (2), (Z)‐N‐[2‐(4‐hydroxyphenyl)ethyl]‐3‐methyldodec‐2‐enamide (3), 5α,7αH‐eduesm‐11(13)en‐4α‐ol (4), 24‐methylenecholesterol (5) and 1β‐hydroxy‐α‐cyperone (6) have been isolated from a Formosan soft coral Sinularia sp. The structures of the above compounds were determined by spectral analyses. Cytotoxicity of compounds 1–6 toward various cancer cell lines also is reported.
A Model Calculation for the Isomerization and Decomposition of Chemisorbed HCN on the Si(100)‐2×1 Surface
Authors: Bacalzo‐Gladden F. , Musaev D. G. , Lin M. C. 
Published: May 2015

AbstractAb initio molecular orbital and hybrid density functional theory calculations have been performed to study the adsorption, isomerization, and decomposition of HCN on Si(100)‐2×1 using the Si9H12 cluster model of the surface. The results of our calculations indicate that the HCN can adsorb molecularly without a barrier onto the surface with both end‐on (LM1) and side‐on (LM2) positions. LM1 can isomerize to LM2 with a small barrier of 8 kcal/mol. The isomerization of LM2 by H‐migration from C to the N atom, requires 76 kcal/mol activation energy (c.f. 47.5 kcal/mol in the gas phase) because of surface stabilization. Both HCN(a) and HNC(a) end‐on adsorbates were found to dissociate readily, as concluded in our earlier experiment, to produce H and CN adspecies. The computed vibrational frequencies of HCN, CN, and also HCNH adspecies agree reasonably well with those observed experimentally. HCNH was found to be stable, with either the C or the N attaching to the surface.
On the Search for H5O2+centered Water Clusters in the Gas Phase
Authors: Chang Huan‐Cheng , Jiang Jyh‐Chiang , Chang Hai‐Chou , Wang Yi‐Sheng , Lin Sheng H. , Lee Yuan T. 
Published: May 2015

AbstractIn searching for H5O2+‐centered water clusters, we employed vibrational predissociation spectroscopy and ab initio calculations. Structures of the clusters were characterized by the free‐ and hydrogen‐bonded‐OH stretches of ion cores and solvent molecules. Systematic examination of H+(H2O)5–7 in a supersonic expansion reveals the presence of both cyclic and noncyclic forms of H5O2+‐centered water clusters. The proton transfer intermediate H5O2+(H2O)4 was identified, for the first time, by its characteristic hydrogen‐bonded‐OH stretches of the ion core at 3178 cm−1. Also discovered at n = 7 is the H5O2+‐containing five‐membered ring isomer, whose existence is evidenced by the observation of a bonded‐OH stretching doublet at 3544 and 3555 cm−1 of the solvent molecules. The observations are in accord with ab initio calculations which forecast that H5O2+(H2O)4 and H5O2+(H2O)5 are, respectively, the lowest‐energy isomers of protonated water hexamers and heptamers.
Total Synthesis of Dimethyl Glolosiphone A via α‐Carbonyl Radical Spiro‐Cyclization
Authors: Sha Chin‐Kang , Ho Wen‐Yueh 
Published: May 2015

AbstractA general approach toward spiro[4.4]nonane structure based on the α‐carbonyl radical cyclization has been developed. Efficient total synthesis of dimethyl gloiosiphone A (2) was achieved. Thus, alkylation of the anion of dimethylhydrazone of cyclopentanone with 5‐iodopent‐1‐yne followed by hydrolysis gave ketone 4. Iodination of 4 via its TMS‐enol ether yielded iodo ketone 7. Radical spiro‐cyclization of 7 gave spiro ketone 10. Iodination of 10 afford iodo spiro ketone 23. Oxidation and iodination of 23 gave compound 24. Methylation of 24 furnished methoxy iodo enone 25. Substitution of iodide in 25 with methoxide produced dimethoxy enone 26. Allylic oxidation of 26 gave diketone 27. Treatment of 27 with OsO4 and N‐methylmorpholine N‐oxide gave dihydroxy ketone 28. Methylation of the primary alcohol group in 28 afforded dimethyl gloiosiphone A (2).
Sesquiterpenes from the Roots of Ligularia duciformis
Authors: Gao Kun , Yang Li , Jia Zhong‐Jian 
Published: May 2015

AbstractTwo new sesquiterpenes named liguducin‐A (1) and ‐B (4) were isolated from a Chinese medicinal plant, the dried roots of Ligularia duciformis, together with four known sesquiterpenes, 4α, 10β‐dihydroxy‐1β,5α‐H‐guai‐6‐ene (2), 4α‐hydroxy‐1β,5α,11α‐H‐guai‐9‐en‐12,8α‐olide (3), 1β‐hydroxyeudesm‐4,11‐dien‐3‐one (5) and 1β,6α‐dihydroxyeudesm‐4(15)‐ene (6). On the basis of the spectral evidence, their structures were determined.
Determination of Arsenic and Mercury in Various Environmental Matrices by Chemical Neutron Activation Analysis
Authors: Lo Jem‐Mau , Wei Ju‐Chin 
Published: May 2015

AbstractChemical neutron activation analysis was developed for determining trace amounts of arsenic and mercury in a variety of environmental matrices, including water, sediment, rock, plants, animal organs, etc: The adsorption procedure via magnesium oxide as the agent was applied to preconcentrate arsenic from the digested environmental matrices where arsenic in the form of As(V) ion could be highly efficiently adsorbed by hydrous magnesium oxide. On the other hand, the extraction procedure via lead diethyldithiocarbamate as the agent was applied to preconcentrate mercury from the digested environmental matrices where mercury in the form of Hg(II) ion could be highly efficiently extracted into the solution of lead diethyldithiocarbamte in dichloromethane. Both of the preconcentrated materials prepared ultimately in the solid states, i.e., arsenic in magnesium oxide and mercury in lead diethyldithiocarbamte were taken to be neutron irradiated. The γ spectra of the preconcentrated samples irradiated generally showed clear peaks of the product radionuclides from arsenic or from mercury by the different separation procedures. The possible interfering elements such as Na, Br, etc., were prominently minimized in respect of most of the preconcentrated samples. The reliability and accuracy of the proposed analytical methods for detecting arsenic and mercury can be confirmed by the assay of commercial standard reference materials including sediment, rock, plants, and animal organs.
Removal of Heavy Metals from Plating Wastewater by Crystallization/Precipitation of Gypsum
Authors: Huang Chein‐Ho , Wu Cheng‐Kwung , Sun Ping‐Ching 
Published: May 2015

AbstractA high surface area was created during nucleation and crystal growth of gypsum by mixing calcium and sulfate ions, causing adsorption of heavy metals on the colloids of gypsum and capsulation in the subsequent precipitation process. In addition to the effect of surface area, zeta potential and surface pH of the gypsum colloids, ionic strength of solution, as well as solubility and particle size of the metal hydroxide influenced the extent of uptake of heavy metals from wastewater.
Enzymatic Reaction in Supercritical Fluid Carbon Dioxide Using Dry‐Ice
Authors: Yu Hui‐Ming , Lin Han‐Liang , Wu Chi‐Yue , Tseng Ming‐Jen , Chen Shui‐Tein , Jeyashoke Narumon , Krisnangkura Kanit 
Published: May 2015

AbstractNew enzymatic reactions in supercritical fluid carbon dioxide catalyzed by lipases (PPL, Lipase MY, Candida cylindracea Lipase), and Proteases (subtilisin Carlsberg, subtilisin 8397, immobilized papain) with high efficiency and yields in a simple high pressure reactor using readily available dry‐ice have been developed.
Inhibition of Trichothecin and Ergosterol Biosynthesis in Trichothecium roseum by Lovastatin
Authors: Huang Wan‐Ling , Lee Kuan Rong , Shiao Ming‐Shi 
Published: May 2015

AbstractThe effect of lovastatin, an HMG‐CoA reductase inhibitor, on the biosynthesis of trichothecin, ergosterol, and fatty acids in the fungus Trichothecium roseum was investigated. Treatment of lovastatin (50 μM) to a 5‐day‐old culture of T. roseum reduced the incorporation of [2‐14C]acetate into trichothecin by 79%, whereas the conversion of [5‐3H]mevalonate into this sesquiterpenoid mycotoxin was reduced by only 28%. In a parallel experiment, the incorporation of [2‐14C]acetate and [5‐3H]mevalonate into ergosterol were decreased by 78% and 17%, respectively. Meanwhile, the conversion of labeled acetate into fatty acids was not significantly affected. These results indicate that HMG‐CoA reductase is a major, but not strict, regulatory site in mevalonic acid pathway leading to the formation of trichothecin and ergosterol. No priority was found in utilization of a single, residual mevalonic acid pool in response to lovastatin inhibition for the biosynthesis of trichothecin and ergosterol. Inhibition of mevalonic acid formation does not significantly divert acetyl CoA into fatty acid synthesis.
Cu2+‐ATPases: Sequence Analyses and Implications in the Wilson Disease
Authors: Liaw Shwu‐Huey , Chuang Lee‐Ming 
Published: May 2015

AbstractWilson disease is an autosomal recessive disorder of copper metabolism, and the defective gene codes for a P‐type Cu2+‐ATPase. Sequence comparison revealed that the Cu2+‐ATPases were very distinct from the Ca2+‐, Na+‐ H+‐, and K+‐ATPases, which however, shared significant similarity to each other. The major difference may be due to the difference in metal ligand preference. Some novel conserved motifs in the Wilson disease protein were also identified, including a putative Walker A motif (GCGIGCKV, residues 1099–1106), and a Walker B motif (GDGVND, residues 1266–1271) for the cofactor ATP binding and hydrolysis, a unique KAPIQ motif (residues 910–914) in the transduction domain, and some motifs in the transmembrane segments probably for the substrate specificity. Combining with the previous genetic and biochemical data, some conserved residues could be assigned for possible functions. This information should provide a guide for designing future studies of structure‐function relationships in the Wilson disease gene. Sequence analysis is also useful in distinguishing whether the mutant residues are missense or polymorphism, such as T977M was identified as a missense mutation because only small amino acid residues appear at this position.
Solvolysis of 1‐Aryl‐1‐tert‐butylmethyl Bromides. Hammett‐Type Correlation Analysis and Revised YBnBr Scale
Authors: Liu Kwang‐Ting , Chin Chin‐Pu , Yu Der‐Gann , Duann Yeh‐Fang 
Published: May 2015

AbstractThe solvolysis of a series of 1‐aryl‐1‐tert‐butylmethyl bromides (1a–1g) in a variety of solvents were carried out. Linear relationships were observed from Hammett‐type analysis of logarithm of rate constants using single‐parameter Brown‐Okamoto equation (Eqn. 1) and dual‐parameter Yukawa‐Tsuno equation (Eqn. 2), respectively. The ρ values and the γ values were found to depend mainly on the range of substituents and not the type of solvents employed. The observation of an upward deviation for the data points of strongly deactivating substrates 1f and 1g could be interpreted by an electrophilic acceleration owing to the solvation of leaving group. It is likely an additional example of overshadowed solvent effect in the dual‐parameter treatment of rate data. Moreover, the variation of γ values was found contradicting the general consideration of resonance contribution. The observed excellent linear correlations with YBnBr and the good solubility in aqueous solution with high percentage of water made 1c a better reference standard than 2‐bromo‐2‐(4‐trifluormethyl)adamantane (3) for obtaining revised and extended YBnBr values. Correlation analysis using the single‐parameter Grunwald‐Winstein equation (Eqn. 3) with YBnBr was found to be superior over the dual‐parameter equation containing YBr and I (Eqn. 5).
Preparation and Properties of a New Chelating Resin Containing Sulfur and Nitrogen Donor Atoms
Authors: Chen Min‐Jane , Liu Chuen‐Ying 
Published: May 2015

AbstractA novel chelating resin was obtained by incorporating 2‐mercaptoethylamine into polystyrene divinylbenzene copolymer. Conversion of functional groups of the resin was confirmed by IR spectra, elemental analysis, hydrogen capacity, and protonation constants. The functionality of the resin is 0.45 mmol g−1. The water regain as a function of pH was determined. The coordination behavior of the resin was investigated by IR, EPR and potentiometry. Effects of pH on adsorption of metal ions to the resin, both at large excess and limited amount of metal ions were examined. The resin exhibits exceptionally high affinity for soft metal ions, even in highly acidic aqueous media. EPR measurements at different copper loading were made. The results showed that the copper(II)‐resin complex might be distorted tetragonal. Protonation constants and stability constants of the resin were determined at 25 °C and ionic strength of 0.5 M KCl solution. The selectivity of the resin toward metal ions decreased in the order: Au(III) > Pt(IV) > Ag(I) > Pd(II) > Hg(II) > Fe(III) > Cu(II) > Zn(II) > Cd(II) > Ni(II) ≡ Co(II). Metal ion coordination occurs primarily at the nitrogen and sulfur donor atoms, but the polymeric backbone also makes significant contribution to metal binding. The resin demonstrated high promise for the collection and analysis of noble metal ions, especially from complex matrix samples.
Polarographic Study of Thallium(I) Complexes with Large Crown Ethers in Binary Acetonitrile‐Water Mixtures
Authors: Farhadi Khalil , Shamsipur Mojtaba 
Published: May 2015

AbstractThe 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

AbstractExamination 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

AbstractThe 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

AbstractUsing 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

AbstractThe 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

AbstractThe 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

AbstractLinear 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

AbstractA 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

AbstractThe 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.