bluuebunny/crossref_metadata_2025_split huggingface dataset:
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

AbstractTo 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

AbstractModeling 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

AbstractThe 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

AbstractA 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

AbstractThe 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

AbstractA 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.
Reaction of Y(Ba1.5Sr0.5)Cu3Oy with Water
Authors: Lin Ching‐Huang , Kao Huey‐Chuen I. 
Published: May 2015

AbstractReaction of superconducting Y(Ba1.5Sr0.5)Cu3Oy (abbreviated as YS‐123) powder with water in a closed system at pH 7 and 25 °C, after 150 h, the concentration ratio of Y:Ba:Sr:Cu ion in the solution is 0.0025:1:0.33:0.0003. Mass equation of the reaction is similar to that of YBa2Cu3Oy (abbreviated as Y‐123). Leaching rate of the Ba ion is higher than that of the Sr ion at the beginning of the reaction, which reflects the basicity difference between these two alkaline earth elements. The initial rate equation is expressed as Ro = k [S]oa [H3O+]ob. [S]o is the initial surface area of YS‐123 powder and H3O+ a catalyst. a and b are found to be 0.99 ± 0.02 and 0.58 ± 0.02, respectively. The initial rate, Ro, for 100.1 mg powder with a mean radius of 0.025 mm at pH 7 and25°C is 1.35 × 10−6 mol·min−1. Rate constant, k, is (0.54 ± 0.03), (1.1 ± 0.1) and (1.90 ± 0.08) × 10−3 mol·min−1·cm−2·M−0.6 for the reaction at 10, 25 and 40 °C, respectively, by using a = 1 and b = 0.6 for calculation. Activation energy (Ea) and pre‐exponential factor (A) calculated from the Arrhenius equation are 31.2 ± 0.4 kJ·mol−1 and (3.0 ± 0.4) × 102 mol·min−1·cm−2·M−0.6. Although the amount of Sr substitution to Ba is only 25%, initial reaction rate of YS‐123 in water is 2 orders magnitude smaller than that of Y‐123 at pH 7.
Constituents from Rubia Ustulata Diels and R. Yunnanensis Diels and Their Antiplatelet Aggregation Activity
Authors: Liou Meei‐Jen , Teng Che‐Ming , Wu Tian‐Shung 
Published: May 2015

AbstractA new anthraquinone glycoside, rubiayannone‐A (1), and a new coumarin, rubilatin‐A (2), together with twenty‐two known compounds were isolated and characterized from the roots of Rubia ustulata. A new anthraquinone, 2‐carbomethoxyanthraquinone (3), and rubiayannone‐A, 2‐formylanthraquinone were obtained from the roots of R. yunnanensis. The structures of those compounds were elucidated by spectroscopic methods. The antiplatelet aggregation activity of the isolated compounds 1, 4∼6 were also discussed.
Synthesis and Structure Determination of Some New N‐Glycosides of 4,5‐Disubstituted‐1,2,4‐Triazole‐3‐Thiones
Authors: Zamani Khosrow , Faghihi Khalil , Iqbal Rashid 
Published: May 2015

AbstractSome new N‐glycosides of 4‐(2‐phenylethyl)‐5‐pyridyl‐1,2,4‐triazole‐3‐thiones were synthesised by the coupling reaction of halo sugar with 4,5‐disubstituted 3H‐1,2,4‐triazole‐3‐thiones in the presence of mercuric cyanide and dry nitromethane as solvent, followed by deprotection using dry ammonia in methanol. All of the above compounds were fully characterized by means of infrared, 1H NMR spectroscopy, mass spectroscopy and elemental analysis.
Use of Raman Spectroscopy in Biological Compounds
Authors: Tu Anthony T. 
Published: May 2015

AbstractThe invention and subsequent use of laser as a light source in Raman spectroscopy ignited a wide application of Raman spectroscopy to organic compounds, biological compounds, and to biological tissues. Raman spectroscopy is a vibrational spectroscopy; Raman frequency is related to the mode of various vibrations in a molecule.In this review article, the use of Raman spectroscopy on biological molecules done at A. T. Tu's laboratory from 1962 to 1998, until his retirement, is summarized. The first part of the article is on peptide backbone structure and the local environment of amino acid residue side chain in proteins, mainly on snake neurotoxins. The second and third parts are direct analyses of gallstones and kidney stones by Raman spectroscopy without extraction, separation, and tedious chemical analysis. The last part is about the use of Raman spectroscopy to determine the anomeric bond in hexapyranosyl compounds.
Progress in the Recent Discovery and Development of Promising Anticancer and Anti‐HIV Agents from Natural Products in the United States
Authors: Wu Jiu‐Hong , Morris‐Natschke Susan L. , Lee Kuo‐Hsiung 
Published: May 2015

AbstractAs the 21st century begins, consumers in all countries are accepting natural medicines to improve quality of life, maintain health, and treat chronic and age‐related diseases. Accordingly, scientists worldwide are increasingly interested in the discovery and development of new drugs from plant, marine, and other sources. Natural resources have become more attractive as potential sources of new medicines, especially to treat cancer and AIDS. Recent progress in these areas will be discussed with emphasis on the discovery and development of clinically useful compounds as well as candidates for clinical trials. Contributions in these areas from the authors' laboratory will also be included.
Electroanalytical Kinetic and Diffusion Studies for the Reduction of 4‐Cyano‐3‐substituted Sydnones
Authors: Wang Lai‐Hao , Tien Hsien‐Ju 
Published: May 2015

AbstractThe electrochemical reduction mechanism of five 4‐cyano‐3‐substituted sydnones was investigated at a hanging mercury drop electrode by cyclic, linear sweep and differential pulse voltammetric methods in Britton‐Robinson buffer (pH 1.68–11.76). The electrode kinetics of 4‐cyano‐3‐(p‐tolyl)sydnone were studied in protic and aprotic solvent containing different tetra‐alkylammonium salts supporting electrolytes, respectively.
Time‐Resolved Thermal Lensing Studies on Metastable Species
Authors: Cheng Chung‐Chih , Wu Guo‐Ray , Chiou Chau‐Shuen , Yu Jen‐Kan , Chou Pi‐Tai 
Published: May 2015

AbstractTime‐resolved thermal lensing (TRTL) techniques have been applied to resolve photophysical and thermodynamic parameters for various metastable species, of which the relaxation dynamics are dominated by the radiationless transition. Using 1H‐phenalen‐1‐one as a sensitizer, the lifetime (τΔ), absolute quantum yield (ΦΔ) and efficiency of generation (STΔ) of singlet molecular oxygen (1Δg) have been determined in various organic solvents. In particular, through the development of an ultrasensitive detecting system, TRTL studies on the relaxation dynamics of O2(1Δg) become feasible in aqueous solution. In another application, based on the TRTL technique in combination with the O2 sensitization experiment, the T1‐S0 energy gap of the proton‐transfer tautomer in 3‐hydroxyflavone, which is otherwise inaccessible due to the dominant radiationless deactivation, has been deduced to be ∼ 8500 ± 1020 cm−1.
Enhancement of Chemiluminescence from the Oxidation of Luminol with Hydrogen Peroxide Catalyzed by Mn(III)‐Microperoxidase 8
Authors: Yeh Hui‐Chun , Lin Wann‐Yin 
Published: May 2015

AbstractMn(III)‐containing microperoxidase 8 (Mn(III)‐MP8) is an effective catalyst for the cheminluminescent (CL) reaction involving the oxidation of luminol with hydrogen peroxide at high pH. The CL emission was dramatically enhanced by the presence of guanidine hydrochloride or sodium carbonate in the reaction mixture. The enhancement was strongly pH‐dependent, with the most prominent pH at 10. Kinetic studies of the CL reaction have revealed that the enhancement was caused primarily by the significant acceleration of the CL cycle by the enhancer. The CL signal covers several orders of magnitude over a wide concentration range of luminol and hydrogen peroxide. The intense CL of the [Mn(III)‐MP8]‐luminol‐H2O2 system, especially in the presence of the enhancer, will have a great potential for extremely sensitive CL assays.
A Simple and Efficient Esterification Method
Authors: Chen Ming‐Yi , Lee Adam Shih‐Yuan 
Published: May 2015

AbstractA convenient and practical esterification was realized and this reaction proceeded without a dehydrating reagent or water removal equipment. The synthesis of esters by reaction of carboxylic acids with various alcohols such as methyl, ethyl, isopropyl, isobutyl, allyl, benzyl, propargyl and decanyl alcohols were achieved with a catalytic amount of CBr4 under refluxing reaction conditions.
Synthesis and Characterization of Organosoluble Copolyimides Based on 3,3′,4,4′‐Diphenylsulfonetetracarboxylic Dianhydride and a Pair of Aromatic Diamines Containing 1,2‐Bis(4‐Aminophenoxy)‐4‐tert‐Butylbenzene
Authors: Yang Chin‐Ping , Chen Ruei‐Shin , Wang Ming‐Jui 
Published: May 2015

AbstractA series of copolyimides was synthesized from commercial 3,3′,4,4′‐diphenylsulfonetetracarboxylic dianhydride with a pair of diamines, which contained 1,2‐bis(4‐aminophenoxy)‐4‐tert‐butylbenzene. The intermediate poly(amic acid)s had the inherent viscosities of 0.52–1.52 dL/g and were thermally converted into copolyimides. These copolymers were soluble in a variety of organic solvents such as NMP, DMAc, and DMF, and almost all of them could even be dissolved in less polar solvents such as m‐cresol, pyridine, and dioxane, showing a better solubility than corresponding homopolymers. Copolyimide films had tensile strengths of 87–160 MPa, elongations at a break of 9–12%, and initial moduli of 1.9–2.2 GPa. The glass transition temperatures of these copolymers were in the range of 262–288 °C, lower than that of homopolymers. The copolyimides had 10% weight loss temperatures in the range of 495–522 °C under nitrogen and 508–521 °C under air atmosphere, and they left more than 43% residue even at 800 °C in nitrogen. The thermal stability of copolymers was somewhat sacrificed due to the copolymerization, but they still belong under heat‐resistant polymeric materials.
Photochemical Synthesis of 2,2′‐Biflavanones from Flavone
Authors: Chen Arh‐Hwang , Kuo Wei‐Bao , Chen Chia‐Wen 
Published: May 2015

AbstractPhotolysis of flavone (4) with the electron‐donating amines including triethylamine or 2‐(N,N‐dimethylamino)ethanol in acetonitrile, benzene or methylene dichloride can easily afford two hydrodimers of 2,2′‐biflavanone(racemate) (5a) and 2,2′‐biflavanone(meso) (5b) and one reductive product of flavanone (6). Their yields were dependent on the molar ratios of substrate to amine, the kinds of amines, the solvents used and the irradiation sources. Higher yields were afforded 2,2′‐biflavanone(racemate) (5a), 2,2′‐biflavanone(meso) (5b) and flavanone (6) (30.0%, 20.9% and 15.8%, respectively) in the reaction condition of 1/2 molar ratio of flavone (4) to triethylamine in acetontrile with fourteen hours of irradiation.
Cytotoxic Constituents of the Leaves of Calocedrus Formosana
Authors: Chiang Yi‐Ming , Liu Han‐Kang , Lo Jir‐Mehng , Chien Shih‐Chang , Chan Yih‐Fwu , Lee Tzong‐Huei , Su Jen‐Kuan , Kuo Yueh‐Hsiung 
Published: May 2015

AbstractThe isolation and identification of twenty‐seven components from the leaves of Calocedrus formosana are described. Their structures were determined on the basis of spectral data as well as direct comparison with authentic samples. These compounds include a mixture of fatty acids, five benzenoids, two lignans, one sesquiterpene, fifteen diterpenoids, one steroid and two phaeophorbides. Some of these compounds exhibited cytotoxic activity.
Bromelain Catalyzed Synthesis of Peptides in Organic Solvent
Authors: Tai Dar‐Fu , Fu Shu‐Lin 
Published: May 2015

AbstractFor the first time, immobilized bromelain was shown to maintain high catalytic activity in organic solvent and to form peptide bonds. It requires only 7 hours to obtain Cbz‐Gly‐l‐Leu‐OMe in 85% yield. The precursor of aspartame (Cbz‐l‐Asp‐l‐Phe‐OMe) and other dipeptides were also synthesized by this method.
Novel DNA Binding Agents: Hydrazone‐based Helical Trinuclear Ag Complexes
Authors: Cheng Chien‐Chung , Hung Sue‐Mei , Yeh Chia‐Yi , Chang Chen‐Shen , Wang Wen‐Jwu 
Published: May 2015

AbstractUsing the hydrazone linker and the self‐assembly, functionalized Ag complexes with a helical structure showed a 2.96 Å distance between metal‐metal bonds, well‐aligned aromatic rings, and the strong affinity toward DNA.
Conductimetric Studies of Charge Transfer Complexes of p‐Chloranil with Some Alicyclic Amines in Polar Media
Authors: Sayed Nadia I. Abdel , El Badry Karima , Mohsen Hassan M. Abdel 
Published: May 2015

AbstractThe stoichiometry of charge‐transfer complexes which ionise in polar media has been studied by conductimetric titration technique in the systems morpholine‐p‐chloranil (CA), piperidine‐CA and pyrrolidine‐CA in three different polar solvents namely N,N‐dimethylformamide, acetonitrile and dimethylsulfoxide at different temperatures of 10, 15, 18, 20, 25 and 30 °C. The stoichiometric ratios of these complexes were found to vary from 1:1 to 1:4 (acceptor: donor) depending on the system, temperature and solvent used. The ασM‐values of these complexes have been reported. The effect of solvents, temperatures and types of electron donors on the σP‐values has been examined.
Application of Weakly Oriented Non‐ionic Liquid Crystal Solvents to NMR Studies of Poly‐ethylene Oxide (PEO)
Authors: Liu Pin‐Hsiu , Ding Shangwu 
Published: May 2015

AbstractWe report in this article the application of a series of weakly ordered liquid crystal solvents for liquid state nuclear magnetic resonance (NMR) spectroscopy. The solvents are a n‐alkyl‐poly(ethylene glycol)/n‐alkyl alcohol non‐ionic liquid crystal system, first proposed by Ruckert and Otting (J. Am. Chem. Soc. 2000, 122, 7793). The merits of these solvents are further demonstrated by using them with a homogeneous polymer PEO which is one of the most studied polymer electrolyte materials, thus offering an answer to the question of whether the weak anisotropy introduced by liquid crystal solvents has any connection with the large‐scale (≥ one nanometer) heterogeneity (tertiary or higher orders of structure) of the system under study.
Novel Complex Catalyst of η3‐(Pentamethylcyclopentadienyl)dimethylaluminum/Titanium(IV) Butoxide (Cp*AlMe2/Ti(OBu)4) for Syndiotactic Polystyrene
Authors: Chen Yu‐Pin , Tsai Jing‐Cherng , Hong Jin‐Long 
Published: May 2015

AbstractA novel metallocene catalyst was prepared from the reaction of (η3‐pentamethylcyclopentadienyl)dimethylaluminum (Cp*AlMe2) and titanium(IV) n‐butoxide Ti(OBu)4. The resulting titanocene Cp*Ti(OBu)3 was combined with methylaluminoxane (MAO)/tri‐iso‐butylaluminum (TIBA) to carry out the syndiotactic polymerization of styrene. The resulting syndiotactic polystyrene (sPS) possesses high syndiotacticity according to 13C NMR. Catalytic activity and the molecular weight of the resulting sPSs were discussed in terms of reaction temperature, concentration of MAO, amounts of scavenger TIBA added, and the hydrogen pressure applied during polymerization.
Syntheses, Structures and Spectroscopic Studies of Dimolybdenum Complexes Containing Bridging Butyrate and Phosphine Ligands
Authors: Suen Maw‐Cherng , Chen Jhy‐Der , Keng Tai‐Chiun , Wang Ju‐Chun 
Published: May 2015

AbstractBy reactions of Mo2(O2CPrn)X2(PPh3)2 (X = Cl, 1; X = Br, 2) with Ph2PCH2CH2P(Ph)CH2CH2PPh2 (etp) in CH2X2, the quadruply bonded complexes containing bridging butyrate and tridentate phosphine ligands of the type Mo2(O2CPrn)X3(η3‐etp) (X = Cl, 3; X = Br, 4) were prepared. Their UV‐vis and31P{1H}‐NMR spectra have been recorded and the structures of 1 and 2 have been determined by X‐ray crystallography. Crystal data for 1: space group P21/c, a = 9.708 (2)Å, b = 18.491 (4)Å, c= 12.688 (3)Å, β = 110.76 (3)°, V = 2130 Å3, Z = 2, with final residuals R = 0.0441 and Rw = 0.0519. Crystal data for 2: space group P21/c, a = 9.737 (1)Å, b = 18.632(1)Å, c = 12.680(1)Å, β= 110.27 (1)°,V = 2158.2 (3) Å3, Z = 2, with final residuals R = 0.0322 and Rw = 0.0481. The δ → δ* transition energies, 31P{1H}‐NMR chemical shifts and the coupling constants are dependent on the natures of the halogen atoms and the carboxylate ligands. The through metal‐metal couplings |3JP‐Mo‐Mo‐P| for complexes of the type Mo2(O2CR)X3(η3‐P3), which contain η3‐polydentate phosphine ligands are about 20 ± 2 Hz.