bluuebunny/crossref_metadata_2025_split huggingface dataset:
1H, 2H, 19F, 31P, and 35Cl NMR Studies on Molecular Motions in Ionic Plastic Phases of Pyrrolidinium Perchlorate and Hexafluorophosphate
Authors: Ono Hiroshi , Ishimaru Shin’ichi , Ikeda Ryuichi , Ishida Hiroyuki 
Published: December 2004

Abstract
Measurements of 1H, 2H, 19F, 31P, and 35Cl NMR, differential scanning calorimetry (DSC), and X-ray powder diffraction were carried out in solid pyrrolidinium perchlorate ([C4H8NH2]ClO4) and hexafluorophosphate ([C4H8NH2]PF6). Five and three solid phases were obtained in perchlorate and hexafluorophosphate, respectively, by DSC measurement above 150 K. X-Ray powder patterns showed the highest-temperature solid phase of both salts to be CsCl-type cubic, indicating that both cations and anions take isotropically disordered orientations. The measurements of the NMR linewidth and its second moment revealed that the C4H8NH2+ and PF6− ions perform self-diffusion as well as isotropic rotation in this phase. From the dynamical behaviour of ions, the highest-temperature phase can be assigned to be an ionic plastic phase; this is the first example of an ionic plastic phase containing pyrrolidinium cations.
Electrocatalysis of O2 Reduction at Glassy Carbon Electrodes Modified with Adsorbed 1,4-Dihydroxy-9,10-anthraquinone Derivatives
Authors: Salimi Abdollah , Mousavi Mir Fazlollah , Sharghi Hashem , Shamsipur Mojtaba 
Published: December 2004

Abstract
The preparation and electrochemical characterization of glassy carbon electrodes modified by four recently synthesized 1,4-dihydroxy-9,10-anthraquinone derivatives are reported. The anthraquinones used were strongly and irreversibly adsorbed on the preanodized glassy carbon electrodes. The electrochemical behavior and stability of the modified electrodes were studied by cyclic voltammetry at different acidic and basic aqueous solutions, and pH of 6—7 was chosen as the optimum working pH. The adsorbed anthraquinone derivatives showed excellent electrocatalytic ability for the reduction of O2 to H2O2 with overpotentials of from 560 to 650 mV lower than that of a plain glassy carbon electrode. The heterogeneous rate constants for the reduction of O2 at the surface of the modified electrodes were determined by rotating-disk electrode voltammetry using the Koutecky–Levich plots. The apparent diffusion coefficient of O2 in buffered aqueous O2-saturated solutions was also estimated.
Recent Advances in the Synthesis of trans-Fused Polycyclic Ethers by Hydroxy-Epoxide-Cyclization and Ether-Ring-Expansion Reactions
Authors: Fujiwara Kenshu , Murai Akio 
Published: December 2004

Abstract
Natural trans-fused polycyclic ethers, produced by marine sources such as dinoflagellates, are hypothesized to be constructed efficiently from the corresponding polyepoxide precursors by a cascade of ring-closure reactions. The efficiency of the biogenetic pathway has been attractive for synthetic chemists and has prompted them to develop new methods for the construction of cyclic ethers from epoxides. In this review, recent advances in the synthesis of trans-fused polycyclic ethers by hydroxy-epoxide-cyclization reactions via monocyclic epoxonium ion intermediates and ether-ring-expansion reactions via bicyclic epoxonium ion intermediates are described.
A Non-Born–Oppenheimer Effective Hamiltonian for the Analysis of Vibrational–Rotational and Rotational Spectra of Diatomic Molecules
Authors: Uehara Hiromichi 
Published: December 2004

Abstract
A non-Born–Oppenheimer effective Hamiltonian for diatomic molecules with optimal fitting parameters, i.e., determinable clusters of expansion coefficients of Born–Oppenheimer corrections, has been derived. The effective Hamiltonian has formally the same form as Dunham’s Hamiltonian, except for additional corrections for successive ξ′i terms of a series expansion of the rotational parameter B(ξ′), extending the determinacy of the optimal parameters, ΔBa,b, Δωa,b, Δaiqa,b, riqa,b, in general for i = 1, 2, 3, ..., if spectra of isotopomers of atoms A and B are analyzed simultaneously. The effective Hamiltonian provides a clear-cut understanding of determinable correction parameters; e.g., in Dunham-type potential fits to spectral transitions for the single isotopomer optimal parameters δriq (i = 1, 2, ...) for corrections of series expansion terms of B(ξ′) should explicitly be included. The physical significance of the optimal parameters as well as of conventional molecular parameters, Be, −De, He, ωe, and −αe, etc., is described.
Photocatalytic Oxidation of Alkanes with Dioxygen by Visible Light and Copper(II) and Iron(III) Chlorides: Preference Oxidation of Alkanes over Alcohols and Ketones
Authors: Takaki Ken , Yamamoto Jun , Komeyama Kimihiro , Kawabata Tomonori , Takehira Katsuomi 
Published: December 2004

Abstract
Visible light irradiation of alkanes in acetonitrile with CuCl2 and FeCl3 catalysts under atmospheric dioxygen gave the corresponding alcohols and ketones effectively; in these reactions, the total selectivity of the products did not decrease so much with increase of alkane conversion. For example, cyclohexanol and cyclohexanone were formed with ca. 70% selectivity at 50% conversion, because overoxidation of the products took place more slowly than cyclohexane oxidation. The relative reactivity values of cycloalkanes increased as their ring-sizes decreased. In the oxidation of hexane, the reactivity ratio of C1-/C2-/C3-H was found to be 1.0/1.4/1.8 with CuCl2 and 1.0/4.6/6.6 with FeCl3, respectively. Toluene and diphenylmethane were more reactive than cyclohexane with FeCl3, as expected, whereas the alkane was oxidized faster than the benzylic compounds in the separate reaction with CuCl2. Moreover, the alkane oxidation could be comparably performed by sunlight instead of an artificial lamp.
p-Type Semiconductors of Aromatic Diamines Doped with SbCl5
Authors: Ganzorig Chimed , Suga Kosaku , Fujihira Masamichi 
Published: December 2004

Abstract
Doping of N,N′-diphenyl-N,N′-bis(3-methylphenyl)-1,1′-biphenyl-4,4′-diamine (TPD) with antimony pentachloride (SbCl5) as a method to form its p-type organic semiconductor material is described. UV–visible absorption and X-ray photoelectron spectroscopic (XPS) data indicated formation of radial cations and dications in TPD films doped with SbCl5. This doping played important roles in hole conduction and in hole injection from an indium-tin oxide (ITO) electrode to the doped TPD layer in typical electroluminescent (EL) organic thin film devices.
New Hole-Transporting Amorphous Molecular Materials with High Glass-Transition Temperatures for Organic Light-Emitting Diodes
Authors: Okumoto Kenji , Shirota Yasuhiko 
Published: December 2004

Abstract
New hole-transporting amorphous molecular materials with high glass-transition temperatures (Tgs), 4,4′,4″-tris[9,9-dimethyl-2-fluorenyl(phenyl)amino]triphenylamine (TFATA) and N,N,N′,N′-tetrakis(9,9-dimethyl-2-fluorenyl)-[1,1′-biphenyl]-4,4′-diamine (FFD), have been developed. TFATA and FFD exhibit hole drift mobilities of 1.7 × 10−5 and 4.1 × 10−3 cm2V−1s−1, respectively, at 293 K at an electric-field of 1.0 × 105 Vcm−1 in their amorphous glasses. These materials permit the fabrication of thermally stable, high-performance organic light emitting diodes.
Oxidative Arylation of Ethylene with Benzene to Produce Styrene
Authors: Matsumoto Takaya , Yoshida Hajime 
Published: December 2004

Abstract
Rh complexes were found to work as catalysts for oxidative arylation of ethylene with benzene to produce styrene by addition of acetylacetone and O2 without any oxidizing agent like Cu salt. Vinylacetate was not formed at all in spite of coexistence of acetic acid.
Thermodynamic Consequences of Single-mutation on Association of an Antibody with Its Specific Antigen: The Case of HyHEL-10-hen Lysozyme Complex
Authors: Tsumoto Kouhei , Kumagai Izumi 
Published: December 2004

Abstract
The interactions between protein antigen and its specific antibodies with one-point mutation have been investigated using isothermal titration calorimetry. Some mutation led to the increase in enthalpy change, and others to the decrease. Contributions of each amino acid to the interaction could be classified with two types, i.e., enthalpic and entropic.
Novel Non-benzenoid Electron Acceptors: Syntheses and Electron Acceptability of Tetracyanoazulenequinodimethanes and Dicyanoazulenequinonemethides
Authors: Sato Ohki , Koizumi Yosuke , Sekiguchi Yoshihiro , Yoshioka Sachiko , Tsunetsugu Josuke , Yan Yong Zhe , Mori Akira , Takeshita Hitoshi , Nozoe Tetsuo 
Published: December 2004

Abstract
Tetracyanoazulenequinodimethanes and dicyanoazulenequinonemethides, a new family of azulene-based electron acceptors have been derived from mono-, di-, and tri-bromo- and -chloro-azulenequinones by reaction with titanium tetrachloride, malononitrile and pyridine. Their unique electron acceptability has been revealed by CV measurement.
Active Species of Molybdenum Carbide Catalysts in Methane Reforming: η-Mo3C2
Authors: Oshikawa Katsuhiko , Nagai Masatoshi , Omi Shinzo 
Published: December 2004

Abstract
η-Mo3C2 was the most active molybdenum carbide species for methane reforming, surpassing β-Mo2C which has been reported previously. From the correlation of the TPR results, the amount of η-Mo3C2 was directly related to the methane decomposition rate, indicating the importance of this type of carbide for methane reforming.
Triplet State of O-Acyloximes Studied by Time-Resolved Absorption Spectroscopy
Authors: Allonas Xavier , Lalevée Jacques , Fouassier Jean-Pierre , Tachi Hideki , Shirai Masamitsu , Tsunooka Masahiro 
Published: December 2004

Abstract
Triplet states of O-acyloximes were studied for the first time by means of laser absorption spectroscopy. Energy transfer experiments showed that the acyl moiety has no effect on the triplet energy, which depends only on the ketone oxime part. It was observed that the difference between the triplet energy of the parent ketone and that of the oxime varies, depending on the oxime structure. This behaviour is explained on the basis of a non-vertical character of the energy transfer reaction.
Oxidized Diamond: A Novel Support for Catalytic Dehydrogenation
Authors: Nakagawa Kiyoharu , Kajita Chiaki , Ikenaga Na-oki , Kobayashi Tetsuhiko , Nishitani-Gamo Mikka , Ando Toshihiro , Suzuki Toshimitsu 
Published: December 2004

Abstract
We found that oxidized diamond played a significant role to improve catalyst performance of Cr2O3 catalyst during the dehydrogenation of C2H6 to C2H4 in the presence of CO2.
Catalytic Asymmetric Borane Reduction of Prochiral Ketones by the Use of Chiral β-Diamines
Authors: Asami Masatoshi , Sato Shinsuke , Watanabe Hiroyasu 
Published: December 2004

Abstract
The catalytic asymmetric borane reduction of prochiral ketones was examined in the presence of chiral β-diamines. Chiral secondary alcohols were obtained with modest to high enantiomeric excesses (up to 92% ee) using (S)-2-[(p-trifluoromethyl)anilinomethyl]indoline.
High Catalytic Activity of As-Synthesized, Ordered Porous Silicate–Quaternary Ammonium Composite for Knoevenagel Condensation
Authors: Kubota Yoshihiro , Nishizaki Yusuke , Sugi Yoshihiro 
Published: December 2004

Abstract
The Knoevenagel condensation of carbonyl compounds with active methylene compounds catalyzed by as-synthesized, ordered porous silicate–quaternary ammonium composite materials gave corresponding α,β-unsaturated esters in high yields under very mild liquid phase conditions.
Thermodynamics and solubility of (U
x
Np1-

x
)O2(am) solid solution in the carbonate system
Authors: Rai Dhanpat , Hess Nancy J. , Yui M. , Felmy Andrew R. , Moore D. A. 
Published: December 2004

Summary
The formation of a solid solution can significantly affect the solubility of a minor component. The objectives of this study were to determine the nature of U(IV) and Np(IV) solid solutions and their thermodynamic properties. For this purpose, (U
x
Np1-

x
)O2(am) precipitates with values of x varying from 0.05 to 0.95 were prepared, characterized, and used to determine their solubility in dilute to concentrated K2CO3 and KHCO3 solutions. The solubility data show that the equilibrium in these systems is reached in < 7 days, the solubility-controlling solids are amorphous, and that we were successful in maintaining U and Np in the tetravalent state. A scanning electron microscope equipped with energy dispersive spectrometry and X-ray absorption spectroscopic analyses of the solids indicated the quilibrated co-precipitates to be solid solutions. A close agreement between the thermodynamic predictions, assuming an ideal solid solution, and the experimental solubilities shows that U(IV) and Np(IV) form an ideal solid solution and that non-ideal solid solution behavior for this system can be ruled out.
Modeling of the complex formation of metal ions with humic acids
Authors: Tochiyama Osamu , Niibori Yuichi , Tanaka Kouichi , Kubota Takumi , Yoshino Hirofumi , Kirishima Akira , Setiawan Budi 
Published: December 2004

SummaryBased on the conceptual model of cation-humic interactions considering the heterogeneous composition and polyelectrolyte nature of humic acids, the description of the interaction by the expression, logKapp= logK-mlog [M]+alogα-blog [Na+], is proposed, whereKapp=[M··(zR)]/([M][R]), [M··(zR)] is the concentration of the cation bound to the humic acid, [M] is the concentration of the free cation with charge z, and [R] is the concentration of the free anionic sites of the humic acid, [R]=(CR-z[M··(zR)])α(CRis a total concentration of proton exchanging sites and α is a degree of dissociation). logK,m,aandbare the constant parameters depending on the cation and the humic acid. The expression is successfully applied to the experimental results on the complex formation (or protonation) of humate and polyacrylate (a homogeneous polymeric weak acid) with H+, NpO2+, Eu3+, Ca2+, Fe2+and Fe3+obtained under the condition where hydrolysis of cations and saturation of the reacting sites can be neglected.
The reduction of U(VI) by near field hydrogen in the presence of UO2(s)
Authors: Spahiu Kastriot , Devoy Jerome , Cui Daqing , Lundström Max 
Published: December 2004

Summary
In several recent works a large impact of dissolved hydrogen on spent fuel dissolution has been observed: the solution concentrations of all redox sensitive components of the spent fuel decrease with time, while gas phase analyses indicate levels of radiolytic oxygen below the detection limit. This indicates that at the relatively low temperatures of these studies (≤70 °C) hydrogen is activated. The aim of this study is to test one of the proposed mechanisms for hydrogen activation, namely by UO2(s) surfaces, which may act as hydrogen catalysts. Dissolved U(VI) carbonate species were used as oxidized species in order to test the reducing ability of hydrogen in the presence and absence of UO2(s). In most cases parallel experiments with the same conditions, but under Ar(g) atmosphere were carried out as blanks. Quartz lined autoclaves avoiding any contact of the solution with metallic parts were used. The experiments were carried out in two stages: first the stability of the (10-7-10-5) M U(VI) in 10 mM NaCl, 2 mM NaHCO3 solutions in the presence of dissolved hydrogen was tested. Then a gold net basket containing UO2(s) fragments was introduced in the autoclave and the concentration of U(VI) was followed at different time intervals by ICP-MS. Various dissolved hydrogen concentrations, temperatures and U(VI) concentrations were used, always spanning the range of these parameters in a proposed deep rock repository. Especially at the lowest U(VI) concentrations tested (∼100 ppb) the activation of dissolved hydrogen by UO2(s) surfaces is clearly visible. As a conclusion of this work it may be stated that in the temperature range (20-70 °C) investigated a) dissolved hydrogen does not reduce U(VI) carbonate species in the absence of a catalyst and b) in the presence of UO2(s) surfaces dissolved hydrogen reduces U(VI) in carbonate solutions, very probably to UO2(s).
The fate of radiolytic oxidants during spent fuel leaching in the presence of dissolved near field hydrogen
Authors: Spahiu Kastriot , Cui Daqing , Lundström Max 
Published: December 2004

Summary
In most European disposal concepts, one expects large amounts of dissolved hydrogen produced by the anoxic corrosion of iron inside a damaged container. At repository temperatures (<100 °C), dissolved hydrogen is quite inert and is not expected to contribute to the redox capacity of the deep groundwaters. In a previous work from this laboratory we observed a large impact of dissolved hydrogen on the dissolution of the spent fuel in stainless steel autoclaves. In this work we report data on spent fuel dissolution obtained using quartz lined autoclaves to ensure that there is no contact between the solution and the metallic parts; we also made a number of other experimental improvements. The autoclave was filled with a solution 10 mM NaCl, 2 mM NaHCO3 and with H2+0.03% CO2 at a pressure of 0.5 MPa in the remaining free volume. The leaching of PWR spent fuel powder, placed in a gold basket, was studied during more than one year by analysing solution samples taken at regular time intervals. Special care was devoted to the study of the initial phase of the dissolution that was not investigated previously. In spite of the ten times lower hydrogen concentration as compared to the study in stainless steel autoclaves, extremely low concentrations of uranium (less than 10-9 M) were again measured in the solution samples; this was the case also for most of the redox sensitive fuel components. The uranium levels in solution remained practically constant during the whole leaching period, indicating the absence of any oxidative dissolution of the spent fuel matrix. In order to follow the fate of radiolytic oxidants, gas phase analyses were also carried out. The radiolytic oxygen levels in the autoclave measured after one year leaching were below the detection limit. A discussion of the fate of the radiolytic oxidants in these experiments and the mechanism of the hydrogen activation is also presented. The main conclusion is that for concentrations of dissolved hydrogen above 4 mM, no measurable oxidative dissolution of the UO2 matrix seems to occur in the studied systems.
Structural changes of uranyl moiety with reduction from U(VI) to U(V)
Authors: Mizuoka Koichiro , Ikeda Yasuhisa 
Published: December 2004

Summary
Redox behavior of UVIO2(dbm)2DMSO (dbm = dibenzoylmethanate, DMSO = dimethyl sulfoxide, 2VI
) and structural properties of UVO2
+ complexes have been investigated with cyclic voltammetry and IR spectroelectrochemical technique, respectively. As a result, it was confirmed that 2VI
is quasi-reversibly reduced to [UVO2(dbm)2DMSO]- (2V
) without any successive reactions, and that 2V
is stable in DMSO. The formal potential for the redox couple, 2V
/2VI
, is -1.362 V vs . the ferrocene/ferrocenium ion redox couple. The IR spectra measured at various applied potentials show a shift of the peak due to the asymmetric stretching (ν3) of O=U=O from 906 to 775 cm-1 with the reduction from 2VI
to 2V
. From the ν3 peak positions, U=O distances of 2V
and 2VI
were estimated as 1.82 and 1.76 Å by Badger´s rule.
Uranium adsorption on weathered schist – intercomparison of modelling approaches
Authors: Payne Timothy E. , Davis James A. , Ochs Michael , Olin Markus , Tweed Cherry J. 
Published: December 2004

SummaryExperimental data for uranium adsorption on a complex weathered rock were simulated by twelve modelling teams from eight countries using surface complexation (SC) models. This intercomparison was part of an international project to evaluate the present capabilities and limitations of SC models in representing sorption by geologic materials. The models were assessed in terms of their predictive ability, data requirements, number of optimised parameters, ability to simulate diverse chemical conditions and transferability to other substrates. A particular aim was to compare the generalised composite (GC) and component additivity (CA) approaches for modelling sorption by complex substrates. Both types of SC models showed a promising capability to simulate sorption data obtained across a range of chemical conditions. However, the models incorporated a wide variety of assumptions, particularly in terms of input parameters such as site densities and surface site types. Furthermore, the methods used to extrapolate the model simulations to different weathered rock samples collected at the same field site tended to be unsatisfactory. The outcome of this modelling exercise provides an overview of the present status of adsorption modelling in the context of radionuclide migration as practised in a number of countries worldwide.
Formation of hydroxyapatite in soils using calcium citrate and sodium phosphate for control of strontium migration
Authors: Moore Robert C. , Sanchez Charles , Holt Kathleen , Zhang Pengchu , Xu Huifang , Choppin Gregory R. 
Published: December 2004

Summary

90Sr contamination is a major problem at several U.S. sites. At some sites, 90Sr has migrated deep underground making site remediation difficult. In this paper, we describe a novel method for precipitation of hydroxyapatite, a strong sorbent for 90Sr, in soil. The method is based on mixing a solution of calcium citrate and sodium phosphate in soil. As the indigenous soil microorganisms mineralize the citrate, the calcium is released and forms hydroxyapatite. Soil, taken from the Albuquerque desert, was treated with a sodium phosphate solution or a sodium phosphate/calcium citrate solution. TEM and EDS were used to identify hydroxyapatite with CO3
2- substitutions, with a formula of (Ca4.8Na0.2)[(PO4)2.8(CO3)0.2](OH), in the soil treated with the sodium phosphate/calcium citrate solution. Untreated and treated soils were used in batch sorption experiments for Sr uptake. Average Sr uptake was 19.5, 77.0 and 94.7% for the untreated soil, soil treated with sodium phosphate, and soil with apatite, respectively. In desorption experiments, the untreated soil, phosphate treated soil and apatite treated soil released an average of 34.2, 28.8 and 4.8% respectively. The results indicate the potential of forming apatite in soil using soluble reagents for retardation of radionuclide migration.
Influence of humic substances on the63Ni migration through crushed rock media
Authors: Tanaka Tadao , Sakamoto Y. , Mukai M. , Maeda T. , Nakayama S. 
Published: December 2004

SummaryColumn experiments were performed to study effects of humic acid on the mobility of63Ni(II) through crushed granite media. The63Ni concentration passing the column increased with increasing the concentration of humic acid. The migration behavior of63Ni, either retarded or non-retarded, could not be simulated by the widely-accepted, instantaneous equilibrium sorption model. The rate limited transformation model, taking into account non-equilibrium complexation of63Ni with humic acid facilitates the description of the observed migration behavior of63Ni.