bluuebunny/crossref_metadata_2025_split huggingface dataset:
Measurement and Linear Correlation of the Solvent Polarity Parameters of Supercritical Carbon Dioxide and Its Cosolvent Systems
Authors: Ikushima Yutaka , Saito Norio , Arai Masahiko 
Published: August 2006

Abstract
The solvent polarity parameters, including the dipolarity/polarizability π* parameter, hydrogen-bond donor acidity α parameter, and hydrogen-bond acceptor basicity β parameter, were measured for supercritical carbon dioxide and cosolvent systems with ethanol, 2,2,2-trifluoroethanol, and dimethyl sulfoxide at pressures of 9.81—27.95 MPa and 318 K. A linear correlation was examined for relating those parameters with each other.
Redox Potentials of Cobalt (III/II) Complexes with Sulfonated Heterocyclic Azo Compounds
Authors: Yuchi Akio , Matsui Katsuhito , Ishizuki Tomosuke , Wada Hiroko 
Published: August 2006

Abstract
Cyclic voltammograms of the cobalt(III) complexes with sulfonated azo compounds indicated one quasi-reversible electrode process at the Pt or Au electrode at −0.3—0 V vs. SCE in aqueous solutions, which was assigned to a metal-centered redox reaction. The formal potentials are linearly correlated with the logarithmic protonation constants of the ligands.
Syntheses and Properties of New (Alkyl)dioxo[tris(3,5-dimethyl-1-pyrazolyl)hydroborato]molybdenum(VI) Complexes
Authors: Onishi Masayoshi , Ikemoto Kazuto , Hiraki Katsuma , Koga Ruri 
Published: August 2006

Abstract
New (alkyl)dioxo[tris(3,5-dimethyl-1-pyrazolyl)hydroborato]molybdenum(VI) complexes, where “alkyl” refers to methyl and trimethylsilylmethyl groups, were prepared as white microcrystals, and were characterized by NMR and IR spectroscopic techniques.
Mechanism for Isomerization of cis-Stilbene via Its Radical Cation as Investigated by Pulse Radiolysis. A Possible Role of a Dimeric Radical Cation as an Intermediate
Authors: Kuriyama Yasunao , Sakuragi Hirochika , Tokumaru Katsumi , Yoshida Yoichi , Tagawa Seiichi 
Published: August 2006

Abstract
Pulse radiolysis of cis-stilbene was carried out and transient absorption spectra were measured in varying concentrations in dichloromethane under air at room temperature. Concentration dependence of the spectral change indicates that cis-stilbene radical cations isomerize to trans-stilbene radical cations through interaction with a neutral cis-stilbene molecule, probably by way of a σ-type dimeric radical cation.
The Pictet-Spengler Reaction on L-Histidine. Preparation of Conformationally Restricted (+)-Pilocarpine Analogs
Authors: Sánchez-Sánchez M del Mar , Tel-Alberdi L M , Rioseras M Jesus , Rico-Ferreira M del Rosario , Bermejo-González F 
Published: August 2006

Abstract
The total regioselective synthesis of the rigid (+)-pilocarpine analogs 4—6 starting from L-histidine is described. The Pictet-Spengler condensation is used to prepare the tetrahydroimidazopyridine moiety present in the structure of these tricyclic derivatives.
Interaction of Methyl Orange with Submicellar Cationic Surfactants
Authors: Dutta Robin K , Bhat Subray N 
Published: August 2006

Abstract
The interaction of aqueous Methyl Orange (MO), an azo dye, with alkyltrimethylammonium and N-hexadecylpyridinium halide surfactants in submicellar concentration ranges has been investigated. The interaction gives rise to a new absorption band of MO with a maximum at ca. 370 nm, and the appearance of the new band has been attributed to change in the chromophore microenvironment in water structure enforced closely packed ion pairs of the dye with submicellar cationic surfactant. The strength of the interaction depends on the alkyl chain length of the surfactant, the surfactant head group and the counter ions.
Semiconductor Photocatalysis: Reaction Mechanisms for the Photoreductive cis–trans Isomerization of Electron-Deficient Alkenes Catalyzed by CdS Powder
Authors: Shiragami Tsutomu , Fukami Shinako , Pac Chyongjin , Wada Yuji , Yanagida Shozo 
Published: August 2006

Abstract
Highly pure commercially available CdS powder (99.999%) catalyzes the effective cis–trans photoisomerization of electron-deficient alkenes under visible light irradiation using triethylamine (TEA) as an electron donor, accompanying the formation of the dihydro compound as a two-electron reduction product. The photoisomerization does not occur at all in the absence of TEA. Donor effect, solvent effect, deuterium incorporation experiments for photocatalysis, and MOPAC molecular orbital calculation (MNDO/PM3) of the intermediary radical anions from the alkenes were investigated in order to elucidate the mechanism of this photoisomerization. These results reveal that the CdS-catalyzed cis–trans photoisomerization should proceed through two pathways involving the photoreduction of alkenes: one through the back electron transfer from the radical anion of the alkene (alkene−•) towards the radical cation of TEA (TEA+•), both formed by photoexcited conduction band electrons and holes of CdS, respectively. The other is the reoxidation of a radical intermediate (alkyl•), formed by protonation of alkene−•, by TEA+•.
Adsorbed Oxygen Species Formed by the Decomposition of N2O on Li/MgO Catalysts
Authors: Nakamura Masato , Yanagibashi Hiroshi , Mitsuhashi Hiroyuki , Takezawa Nobutsune 
Published: August 2006

Abstract
A considerable amount of adsorbed oxygen species were produced by the decomposition of N2O on Li/MgO. The amount of the oxygen species greatly increases by Li(I)-doping on MgO. Over 0.7 wt% Li/MgO, the amount of the oxygen species formed was 10.67 μmol m−2. The temperature-programmed desorption of the oxygen species revealed that two types of adsorbed oxygen species were present on Li/MgO; one (α-oxygen species) desorbed in proportion to the second order in the amount of the adsorbed species with an activation energy of 141 kJ mol−1, giving a peak (α-oxygen peak) at 673—693 K; the other (β-oxygen species) desorbed in proportion to the first order in the amount of the adsorbed species with an activation energy of 219 kJ mol−1, giving a peak (β-oxygen peak) at 753—768 K. A weak α-oxygen peak occurred on MgO and no β-oxygen peak was discerned. On Li/MgO, a β-oxygen peak appeared along with an α-oxygen peak. At higher Li-loadings the β-oxygen peak was more intense than the α-oxygen peak. The sites for these oxygen species were suggested to be derived by the addition of Li(I) on MgO. It was suggested that the α-oxygen species were present at the surface sites on higher index faces of MgO, whereas the β-oxygen species were present at oxygen vacancies in the vicinity of Li(I) substituting for Mg(II). The hydrolysis of these adsorbed oxygen species yielded an appreciable amount of H2O2, suggesting that these species were primarily present as surface peroxide on MgO and Li/MgO.
Influence of Surface Treatment of the p-GaP Photocathode on the Photoelectrochemical Reduction of Carbon Dioxide
Authors: Ikeda Shoichiro , Yamamoto Akio , Noda Hidetomo , Maeda Masunobu , Ito Kaname 
Published: August 2006

Abstract
Effects of the surface treatments of p-GaP electrodes with various etchants on the photoelectroreduction of CO2 were investigated in 0.1 mol dm−3 KHCO3 aqueous solution. The catalytic activities for CO2 photoelectroreduction of p-GaP electrodes depended on the etchants and also their crystallographic orientations, (100) or (111) faces. The reduction products were only HCOO− and CO from CO2, and H2 as a by-product. Aqua regia was prefer to produce HCOO− on both faces. Conc. HCl was effective for HCOO− formation on the (111) face. Although the alkaline potassium hexacyanoferrate(III) solution was effective for reducing the overpotential and increase the photocurrent, the main product was H2. Conc. HNO3 was not effective.
Molecular Dynamics Simulation of Aqueous MNO3 (M = Li, Na, K, Rb, and Cs) Solutions
Authors: Kataoka Yosuke 
Published: August 2006

Abstract
To understand the anisotropy, cation dependence, and concentration dependence of the orientational relaxation time of the nitrate ion, the structure and molecular motion were studied by molecular dynamics simulation of MNO3 (M = Li, Na, K, Rb, and Cs) solutions. The interaction parameters determined for the molten salt were used between the ions. The Carravetta–Clementi potential was assumed for the water–water pair. An empirical combination rule was adopted in the water-ion interactions. Simulations were done at several volumes corresponding to the normal density and low pressures. The temperature was 300 K and the concentrations was 1 or 2 mol kg−1. The distribution of water molecule is almost isotropic around the nitrate ion. No water molecules are found which move in strong correlation with the rotation of the nitrate ion. The calculated orientational relaxation time of the nitrate ion is in agreement with the experimental results qualitatively with respect to its anisotropy, cation dependence, and concentration dependence. These were analyzed by the potential energy of the species around the nitrate ion. The anisotropy of the relaxation time was due to the anisotropic charge distribution in the nitrate ion, as demonstrated by several models.
Liquid Phase Reaction of Acetaldehyde over Various ZSM-5 Zeolites
Authors: Mori Hidemitsu , Yamazaki Tatsuya , Ozawa Sentaro , Ogino Yoshisada 
Published: August 2006

Abstract
Acetaldehyde reacted over various ion-exchanged ZSM-5 zeolites at 15 ± 0.5 °C under a nitrogen pressure of 1 × 105 Pa. The main products of the reaction were 2α,4α,6α-trimethyl-1,3,5-trioxane (cis-paraldehyde) and its isomer, 2α,4α,6β-trimethyl-1,3,5-trioxane (trans-paraldehyde). Several rare earth ZSM-5 (REZSM-5) and M/HZSM-5 (partially proton exchanged ZSM-5) catalysts exhibited high activities for trans-paraldehyde formation. The reaction appeared to proceed by the following scheme: cis-paraldehyde ← acetaldehyde → trans-paraldehyde. A comparison of the catalytic activity with the IR intensity of acidic OH groups over the catalyst suggested that the active site for cis-paraldehyde formation was the Brönsted acidic site, while the active site for trans-paraldehyde formation was a Brönsted acid site in the neighborhood of an Mn+ site in the ZSM-5 zeolite pore.
Photochemistry of Diphenyl Sulfide/Halogen and Mesitylene/Halogen Complexes in Liquid Halocarbons
Authors: Sumiyoshi Takashi , Kawasaki Masahiro , Katayama Meiseki 
Published: August 2006

Abstract
The photochemical reactions of the diphenyl sulfide/X (X = Cl, Br) and mesitylene/X complexes have been studied by the combined pulse radiolysis–laser flash photolysis method. While no photochemistry is observed from the excited state of diphenyl sulfide/Cl complexes in CCl4, permanent photobleaching induced by intermolecular hydrogen abstraction is observed in 1,2-dichloroethane (Φ = 0.05) and in CCl4 which contains an additive such as dichloromethane, cyclohexane, and 2-methyl-2-propanol. The excited state of mesitylene/Cl complexes undergoes solvent independent intramolecular hydrogen abstraction with a quantum yield of 0.10. No photochemistry is observed from the excited states of diphenyl sulfide/Br and mesitylene/Br complexes in CBrCl3 with and without containing cyclohexane. The difference in the bond dissociation energy of H–Cl, H–Br, and C–H explains the dependence of the photochemical reaction modes on both solvents and halogens.
Construction of Defect-Diminished Lithium 10,12-Heptacosadiynoate Monolayer by Means of Crystallization on the Water Surface
Authors: Kuriyama Keisuke , Kajiyama Tisato 
Published: August 2006

Abstract
The melting temperature, Tm of lithium 10,12-heptacosadiynoate monolayer on the water surface was evaluated by a combination of two kinds of measurements, the subphase temperature, Tsp dependence of modulus of the monolayer based on a π–A isotherm and also, the Tsp dependence of the electron diffraction, ED patterns of the monolayer. Tm of the monolayer was evaluated to be 300 K from the results of both an apparent decrease in the Tsp vs. modulus curve and the change of the ED pattern from a crystalline triclinic spot to an amorphous halo. The aggregation structure of the monolayer during a compressing process at Tsp below and above Tm was investigated on the basis of the bright field electron micrograph and the ED pattern. The monolayer on the water surface was classified into a crystalline monolayer and an amorphous one depending on the Tsp below and above Tm of the monolayer, respectively. However, the formation of the crystalline and amorphous monolayers is irrespective of the surface pressure. Furthermore, the defect-diminished crystallized monolayer was prepared by cooling the amorphous monolayer down to a temperature range below Tm.
Spectrophotometric Determination of Palladium(II) Using 4-(Dimethylamino)benzaldehyde Thiosemicarbazone
Authors: Shetty A Nityananda , Gadag Rudrayya V 
Published: August 2006

Abstract
A simple, rapid, and selective spectrophotometric method is proposed for the determination of palladium(II), using 4-(dimethylamino)benzaldehyde thiosemicarbazone (DMABT) as a spectrophotometric reagent. The reagent forms a 1 : 2 complex (Pd : Reagent) with Pd(II) in the pH range 2.2—3.6. The complex is soluble in aqueous solution containing 20% acetone and 30% ethanol by volume. Beer’s law is valid upto 2.3 ppm of palladium. The molar absorptivity is 4.59 × 104 dm3 mol−1 cm−1 and Sandell’s sensitivity 2.33 × 10−3 μg cm−2. The method tolerates large number of cations and anions.
Kjeldahl Digestion Method Formulated by a Criterion Related to the Oxidation Number of Nitrogen
Authors: Shirai Michiko , Kawashima Takeshi 
Published: August 2006

Abstract
A comprehensive Kjeldahl digestion method was formulated based on the criteria that 1) compounds having only nitrogens of oxidation number −III are digested by using H2SO4 with increased K2SO4 without the presence of any other oxidizing agent, and that 2) alternative compounds having nitrogens of oxidation number greater than −III are digested by using H2SO4 with K2SO4 and the reducing agent Zn. This formulation resulted in a satisfactory nitrogen determination of almost all types of organic nitrogen compounds, including those compounds for which it is known to be difficult to analyze using the conventional Kjeldahl method, for example pyridines, pyrazolones, 1,2-diazines, and 1,2,3-triazoles.
Synergic Extraction of Rare Earths(III) with 4,4,4-Trifluoro-1-(2-thienyl)-1,3-butanedione and Nitrogen-Involving Polydentate Ligands as Diethylenetriamine and Triethylenetetramine
Authors: Satake Saeko , Tsukahara Satoshi , Suzuki Nobuo 
Published: August 2006

Abstract
The synergic extraction of rare earths(III), i.e. La, Sm, Tb, and Lu, using 4,4,4-trifluoro-1-(2-thienyl)-1,3-butanedione (Htta) and a nitrogen-involving neutral polydentate ligand, such as diethylenetriamine (dien) or triethylenetetramine (trien), was studied between benzene and aqueous phases. The synergic enhancement of this extraction system was attributed to the formation of an adduct, RE(tta)3dien or RE(tta)3trien. The adduct formation constants (βS,1) were determined. Although βS,1 decreases with the atomic number of RE(III), the detailed tendency of βS,1 depends on the number of nitrogen atoms of the polydentate ligands.
Solvent Extraction of Alkaline Earth Ions with Benzoyltrifluoroacetone into Carbon Tetrachloride in the Absence and Presence of Tetrabutylammonium Ion or Trioctylphosphine Oxide
Authors: Sekine Tatsuya , Takagi Kunihiro , Nguyen Thi Kim Dung 
Published: August 2006

Abstract
The solvent extraction of Mg2+, Ca2+, Sr2+, and Ba2+ (M2+) in aqueous 0.1 mol dm−3 sodium nitrate solutions with benzoyltrifluoroacetone (Hbfa) in carbon tetrachloride was studied in both the absence and presence of tetrabutylammonium ion (tba+) or trioctylphosphine oxide (TOPO). It was found that not only the M(bfa)2 species, but also the tba+M(bfa)3− or the M(bfa)2(TOPO)n species (n is 1 to 3), were extracted by the addition of tba+ or TOPO, and that the extraction was very much enhanced. The equilibria for the extractions were treated as the over-all equilibrium of (i) extraction of the M(bfa)2 chelate and (ii) the association of the ion-pair of the reagents, tba+bfa−, or the TOPO molecules with the chelate in the organic phase. The separation of these four metal ions was improved by the addition of tba+. This was due to the fact that the chelates of smaller M2+ associated with the tba+bfa− better than those of larger M2+ in the organic phase.
Solvent Extraction of Lanthanum(III), Europium(III), and Lutetium(III) with 5,7-Dichloro-8-quinolinol into Chloroform in the Absence and Presence of Tetrabutylammonium Ions or Trioctylphosphine Oxide
Authors: Noro Junji , Sekine Tatsuya 
Published: August 2006

Abstract
The solvent extractions of lanthanum(III), europium(III), and lutetium(III) (M3+) in 0.1 mol dm−3 sodium nitrate solutions with 5,7-dichloro-8-quinolinol(HA) into chloroform were studied in both the absence and presence of tetrabutylammonium ions (tba+) or trioctylphosphine oxide (TOPO). In the absence of tba+ or TOPO, the extracted species were the MA3 and MA3HA (self-adduct), though MA4−tba+ was found when tba+ was added; MA3TOPO and MA3(TOPO)2 were found when TOPO was added in addition to the above mentioned two species. The anionic complex or TOPO adducts greatly enhanced the extraction. The data were statistically analyzed and the equilibrium constants for the extraction of these species, as well as the constants for the association of the HA, the A−tba+, or the TOPO on the MA3 in the organic phase, were determined. The extraction of the MA3 is better in the order LaA3 &lt; EuA3 &lt; LuA3. Although the values of the association constant of the HA or the TOPO on the MA3 are rather similar for the three metal chelates, the constants for A−tba+ are larger in the same order as mentioned above. Thus, the separation of these three metal ions by solvent extraction with this chelating extractant is not much affected by the addition of TOPO, but is greatly improved by the addition of tba+.
Characterization of Calcium-Deficient Hydroxyapatite after a Catalytic Reaction with Trichloroethylene Vapor
Authors: Nishikawa Harumitsu , Ikeda Shigero , Monma Hideki 
Published: August 2006

Abstract
Calcium-deficient hydroxyapatite (DAp) was characterized both before and after an oxidative catalytic reaction with trichloroethylene (TCE) vapor at 450 °C. Most of the Cl in the TCE which decomposed by the reaction was captured as Cl− in DAp. This result supports the assumption reported in a previous paper. On the basis of infrared spectroscopic and X-ray photoelectron spectroscopic results, the captured Cl species was assumed to replace OH− in DAp and to form chloroapatite.
Preparation and Structures of K3[VIII(ox)2(μ-SO4)] and K5[VIII(ox)2(SO4)2]
Authors: Kanamori Kan , Kunita Noriko , Okamoto Ken-ichi , Hidaka Jinsai 
Published: August 2006

Abstract
Two sulfatovanadium(III) complexes, trans-K3[VIII(ox)2(μ-SO4)] (1) and trans-K5[VIII(ox)2(SO4)2] (2), were prepared. The X-ray crystallography of complex 1 showed that the complex consists of a one-dimensional polymer chain with a bridging sulfate ion. In aqueous solution, however, the sulfate bridge is cleaved and the sulfate ion coordinates to vanadium(III) unidentately. Complex 2 has been characterized by elemental analysis, and Raman and infrared spectra.
A Phosphate Staining Reagent Revisited
Authors: Sankar N , Sahal Dinkar 
Published: August 2006

Abstract
A phosphate staining reagent [S. K. Goswami and C. F. Frey, J. Liquid Res., 12, 509 (1971)] was found to show differential staining of phosphate esters. Thus, the staining reaction mixtures in cases of molecules like dodecyl dihydrogenphosphate [DDP], phosvitin and phosphocellulose showed intense blue colors which on standing precipitated down leaving a colorless supernatant. However, at equimolar phosphate concentrations molecules like inorganic phosphate/diphosphate, ATP, and phosphoserine stained poorly. It was apparent that (a) the staining does not involve hydrolysis of phosphate esters and (b) the proximity between phosphate esters determines the staining intensity of different molecular systems. In order to confirm the proximity model, constant amounts of DDP were incubated with the staining reagent in the presence of increasing concentrations of sodium dodecyl sulfate [SDS]. A decrease in staining of phosphate was seen with progressive increase in the concentration of SDS. The slope of this inhibition curve was enhanced when the concentration of DDP was clamped at 300 μM (1 M = 1 mol dm−3) than was the case at 450 μM. The results of these experiments are suggestive of competitive binding of SDS to aggregates of DDP, a phenomenon which decreases the proximity relationship between phosphate head groups of DDP. This has provided us a new method for the estimation of SDS and amphiphiles of similar kind which have the ability to alter proximity relations in DDP aggregates. Phosvitin, a phosphoprotein rich in clusters of intramolecular phosphate esters was only marginally sensitive to the presence of SDS for its staining by this reagent.
Enkephalin Alkylamides As Dimeric Probes for Bivalent Interaction with δ Opioid Receptors
Authors: Shimohigashi Yasuyuki , Tani Ayako , Ohno Motonori , Costa Tommaso 
Published: August 2006

Abstract
The bifunctional interaction of dimeric enkephalins with δ opioid receptors was evidenced by comparing activities between dimers and their monomeric alkylamide analogs having alkyl groups corresponding to the crosslinking spacer. When the tetrapeptide enkephalin amide H–Tyr–d-Ala–Gly–Phe–NH2 was alkylated by a dodecyl group, the resulting enkephalin dodecylamide exhibited only 7—15% activities of those of the nonalkylated amide in the μ assays (muscle assay in guinea pig ileum and rat brain binding assays using [3H]naloxone or [3H]–[d-Ala2,MePhe4,Gly-ol5]enkephalin) and 6—48% activities in the δ assays (muscle assay in mouse vas deferens and binding assays using [3H]–[d-Ala2,d-Leu5]enkephalin or [3H]–[d-Ser2,Leu5]enkephalyl-Thr6). DTE12, a dimer of the structure (H–Tyr–d-Ala–Gly–Phe–NH–(CH2)6–)2 which is created structurally by linking the second tetrapeptide enkephalin molecule to the dodecyl group of enkephalin dodecylamide, was almost as active as enkephalin dodecylamide in the μ assays. However, its δ activities were drastically enhanced, showing 57-fold increase in activity in the muscle assay and 33-fold increase in the brain binding assays when compared with the dodecylamide monomer. Similar results were also obtained for a set of pentapeptide enkephalins; i.e., enkephalin amide H–Tyr–d-Ala–Gly–Phe–Leu–NH2, its ethylamide analog and crosslinked dimer DPE2. The results indicated that the presence of the second peptide in the dimeric enkephalin molecule is responsible for most of increase in biological activities and receptor selection, and that the dimeric enkephalin functions as bivalent ligands for δ receptors.