bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Effect of the Reactor Type on the Selectivity of Thermal Reactions of p-Xylene in Temperature Gradient Systems
Authors: Kawakami Shigenobu , Iwaki Shingo , Nakada Masahiro , Yamaguchi Tatsuaki 
Published: July 2006

Abstract
Thermal reactions of p-xylene were investigated in two kinds of reactors, batch type and flow type, with a large temperature gradient. Excellent differences of the resulting products were observed between these two types of reactors. As for a batch type reactor, 4,4′-dimethylbibenzyl was produced in a high yield with [2.2]paracyclophane and toluene as by-products, and as for a flow type reactor, toluene was obtained as a major product with a low selectivity of 4,4′-dimethylbibenzyl, respectively. These results were different from those of the conventional fast flow pyrolysis method in which [2.2]paracyclophane or poly(3,6-dimethylene-1,4-cyclohexadiene) was formed as a major product. These differences can be accounted for by the partial separation of a reaction mixture caused by the thermal diffusion effect, which arises when the mixture is subject to a temperature gradient.
Unambiguous Proof of Nitrile Formation from Pyrazine Skeleton through Photo-Oxidative Degradation. Isolation and Structural Determination of Photodegraded Product of Amorphous Poly(2,5-distyrylpyrazine)
Authors: Hashimoto Yukihiko , Adegawa Yutaka , Hasegawa Masaki , Onodera Kazuyuki , Sakuragi Hirochika , Tokumaru Katsumi 
Published: July 2006

Abstract
In the presence of oxygen, amorphous poly(2,5-distyrylpyrazine) film was readily photodegraded, accompanied by cleavage of the pyrazine rings in the main chain. From the photodegraded film, t-2,c-4-diphenylcyclobutane-r-1,t-3-dicarbonitrile was isolated in 13% yield.
Oxidation Using Quaternary Ammonium Polyhalides. IX. Oxidation of Hindered Phenols with Benzyltrimethylammonium Tribromide
Authors: Kajigaeshi Shoji , Morikawa Yukihiro , Fujisaki Shizuo , Kakinami Takaaki , Nishihira Keigo 
Published: July 2006

Abstract
Reactions of hidered phenols, such as 2,6-di-t-butyl-4-methylphenol, 3,5-di-t-butyl-4-hydroxybenzyl alcohol, and 2,6-di-t-butylphenol, with benzyltrimethylammonium tribromide were carried out in dichloromethane in the presence of water, t-butyl alcohol, or aqueous sodium hydroxide at room temperature. Sequential reaction processes were provided by the obtained products.
Color Change of (E)-2,3-Bis(2,3,4,5,6-Pentafluorophenyl)-3-[2,3,5,6-tetrafluoro-4-(cyanomethyl)phenyl]acrylonitrile by the Addition of Amines
Authors: Nakayama Yasuhide , Inukai Kazuo , Hayashi Koichiro , Irie Masahiro 
Published: July 2006

Abstract
(E)-2,3-Bis(2,3,4,5,6-pentafluorophenyl)-3-[2,3,5,6-tetrafluoro-4-(cyanomethyl)phenyl]acrylonitrile(3E) was synthesized. A benzene solution of 3E turns into a brilliant red color by the addition of aliphatic amines. The coloration mechanism is studied by optical absorption, conductivity and product analyses. It has become apparent that ion-pair formations between 3E and the amines by proton transfer reactions are responsible for the coloration. Structural requirements of the amines for the ion-pair formation are discussed.
Metal Ion Dependent Site Selective Cleavage of P–O–S Linkage in the Methanolysis of Phenyl Phosphatosulfate
Authors: Eiki Toshio , Tagaki Waichiro 
Published: July 2006

Abstract
Effects of various metal ions on the methanolysis of phenyl phosphatosulfate having P–O–S linkage were investigated. Metal ions examined were found to be divided into two different groups in the manner of cleavage of P–O–S linkage: Mg2+, Cr3+, Cu2+, Mn2+, and Ca2+ with larger ionic radii catalyzed the selective P–O bond cleavage, while Be2+, Al3+, Fe2+, and Zn2+ with smaller ionic radii promoted the selective S–O bond cleavage. Such selectivity was discussed in terms of the difference in the mechanisms of P–O and S–O bond cleavage.
Photokilling of Malignant Cells with Ultrafine TiO2 Powder
Authors: Cai Ruxiong , Hashimoto Kazuhito , Itoh Kiminori , Kubota Yoshinobu , Fujishima Akira 
Published: July 2006

Abstract
Photo-irradiated TiO2 particles drive various chemical reactions due to their strong oxidation and reduction ability. This effect is applied in order to kill malignant HeLa cells with TiO2 particles. During 10-min UV irradiation periods, HeLa cells were completely killed in the presence of TiO2 (100 μg cm−3). However, without irradiation these particles showed little cytotoxicity up to 360 μg cm−3. It is concluded that the cells were killed by hydroxyl (OH·) and perhydroxyl (HO2·) radicals produced from water by the irradiated TiO2 particles, and also that the cells were directly oxidized by photogenerated holes in TiO2. The distribution of TiO2 powders in the cells was observed using a transmission electron microscope. The TiO2 powder existed not only on the cell membrane, but also in the cytoplasm. Thus, the cells were damaged by photoexcited TiO2 not only from the cell membrane, but also from the inside of cytoplasm. Finally, the application of this malignant cell photokilling effect to photodynamic therapy is discussed.
Molecular Motion and Phase Changes in Long Chain Solid Normal Alkanes as Studied by 1H and 13C NMR
Authors: Ueda Takahiro , Takeda Sadamu , Nakamura Nobuo , Chihara Hideaki 
Published: July 2006

Abstract
Proton spin-lattice and dipolar relaxation times and 13C CP/MAS NMR spectra were measured on crystalline samples of n-C50H102 and long chain normal alkanes (n-alkanes) with average molecular weight of 595, 1214, and 2305 in order to characterize the static and dynamic molecular structures in the solid state. The 13C CP/MAS spectra indicate that the molecules take all-trans conformation in the orthorhombic unit cell and do not undergo any discernible change on annealing and/or quenching of specimens. On the other hand, the T1d in each material assumes a deep and clear minimum value in the orthorhombic phase; this relaxation process was unambiguously assigned to the molecular uniaxial reorientation about the long chain axis. There is a linear relation between the activation energy and the reciprocal of the chain length. In the case of n-C50H102 a solid state phase transition was found at 351 K. The T1d in the high temperature phase led to extremely high activation energy, 150 kJ mol−1, which may be attributable to molecular self-diffusion or other motion accompanying drastic change in the molecular structure.
Electrochemical Formation of 11-Molybdophosphate Anion at the Nitrobenzene/Water Interface and Its Applicability to the Determination of Orthophosphate Ion
Authors: Osakai Toshiyuki , Himeno Sadayuki , Saito Atsuyoshi 
Published: July 2006

Abstract
Transfer of the hexamolybdate ion, Mo6O192−, at the nitrobenzene(NB)/water(W) interface was studied by ion-transfer voltammetry. The Mo6O192− ion decomposed immediately after being transfered from NB to W. In the presence of orthophosphate ions in the weakly acidic W phase (pH 3.1), molybdophosphate anions, i.e. [H3PMo11O39]4−, were formed at the interface. A well-defined voltammetric wave due to the transfer of complex anions from W to NB was observed; the peak current was proportional to the bulk concentration of orthophosphate ions. Thus, the NB/W interface containing Mo6O192− in NB can function as an ion-selective electrode surface for a voltammetric determination of orthophosphate ions.
Damage of Egg Phosphatidylcholine Liposomes by DNA-Binding Cytotoxic Agents
Authors: O’Connor Charmian J , Denny William A , Emery Diane P , Tank Holger , Sato Toshinori , Sunamoto Junzo 
Published: July 2006

Abstract
The stability of small unilamellar vesicles (SUV) formed by egg phosphatidylcholine has been examined in the presence of four DNA-intercalating drugs—carboxamides of acridine, anthracene, phenylquinoline, and phenylbenzimidazole. The physicochemical stability of the vesicle-membrane changed as the total drug concentration increased and, of the four drugs investigated, the phenylquinolinecarboxamide was the most destructive. The presence of cholesterol in the liposomal bilayer increased resistance to physicochemically induced damage by the drugs except the anthracenecarboxamide. In all cases, coating the liposomes with a polysaccharide made the liposomal surface more hydrophobic and led to the vesicle rupture by the cytotoxic agents. The cytotoxic 9-anilinoacridine derivatives, amsacrine and 9-[2-methoxy-4-(methylsulfonylamino)anilino]-5-methylacridine-4-N-methylcarboxamide (CI-921), were too insoluble to be encapsulated within the aqueous core of liposomes, but the neutral form of CI-921 was intercalated into the liposomal membrane of pullulan-derivative-coated liposomes. In this formulation, CI-921 was more effective against BM 314 carcinoma-cells than the free drug, but an anticarcinoembrionic antigen (anti-CEA) antibody binding liposome provided no additional advantage.
1H NMR Conformational Study of Viologen-Linked Porphyrins (p-FCnV)
Authors: Yamamoto Yasuhiko , Noda Sumio , Nanai Norishige , Okura Ichiro , Inoue Yoshio 
Published: July 2006

Abstract
Conformation of viologen-linked porphyrins (p-PCnV, n=4–7), which are capable of intramolecular electron transfer, was studied by 1H NMR in order to gain insight into the relative geometry of the donor and acceptor during the electron transfer process. The orientation of the viologen with respect to the porphyrin was interpreted in terms of the rate of the intramolecular electron transfer between the two π-systems.
New Chiral Auxiliary; 4,5-Diphenyl-1-methyl-2-imidazolidinone. Its Utility in Highly Enantioselective Aldol Reaction
Authors: Sankhavasi Wongsiri , Yamamoto Makoto , Kohmoto Shigeo , Yamada Kazutoshi 
Published: July 2006

Abstract
The aldol reaction of the boron enolate bearing the titled chiral auxiliary proceeded with high face selectivity.
Oxidation by Cobalt(III) Acetate. Part 13. Oxidation of Substituted Phenols with Cobalt(III) Acetate in Acetic Acid
Authors: Hirano Masao , Ishii Tadamichi , Morimoto Takashi 
Published: July 2006

Abstract
The oxidation of 2,6-di- and 2,4,6-tri-substituted phenols with cobalt(III) acetate has been investigated in acetic acid under an inert atmosphere; the former gave the corresponding diphenoquinones in excellent yields, and the latter yielded side-chain or nuclear acetoxylated products in moderate to good yields.
Electron Spin Resonance Study of Intrinsic Paramagnetism of Soluble Polyaniline Perchlorates
Authors: Iida Masaki , Asaji Tetsuo , Inoue Motomichi , Grualva Heriberto , Inoue Michiko B , Nakamura Daiyu 
Published: July 2006

Abstract
An ESR study was carried out on two polyaniline perchlorates prepared by different chemical methods: Soluble perchlorate I prepared by the use of copper(II) perchlorate as an oxidative coupling agent, and perchlorate II (corresponding to polyemeraldine perchlorate) obtained by treating a polymer base with perchloric acid. The ESR signal intensity of perchlorate I shows a thermally activated temperature dependence at temperatures between 95 and 300 K. The ESR signal intensity of perchlorate II was temperature-independent. When this polymer adsorbed oxygen, the ESR signal showed a thermally activated paramagnetism resembling that of perchlorate I. These paramagnetic properties can be explained by polaron spins that are antiferromagnetically coupled with each other, and are different from the Pauli-type paramagnetism. This suggests that the charge-transport cannot be explained by the migration of paramagnetic polarons along a polymer chain alone.
Reproduction of Bifurcation Structure of Belousov–Zhabotinskii Reaction in Flow System by Oscillatory Flow Term Oregonator
Authors: Sakanoue Shinji , Murase Chiaki , Endo Mitsuo 
Published: July 2006

Abstract
Simulation has been made on the oscillatory flow term Oregonator model (OFO) proposed in our previous paper for the Belousov–Zhabotinskii reaction (BZ reaction) accompanying constant feed. When the amplitude of the forced oscillation term in OFO is taken extremely small, the computational simulation with this model finely reproduces the oscillatory mode, many types of wave patterns including nonperiodic chaotic behaviors and the bifurcation structure, which appear in the experimental results of the BZ reaction in flow system.
Unusual EPR Profile Obtained by Laser Photoreaction of Cardiovascular Tissue
Authors: Nakagawa Kouichi 
Published: July 2006

Abstract
Using spin trap methods, laser generated free radicals from cardiovascular tissue in high viscosity blood solution have been studied by EPR. The EPR spectra obtained are compared with spectra of free radicals produced by both cw and pulsed excimer laser irradiation. Nitroxide spin adduts produced by excimer laser irradiation show an unusual EPR hyperfine structure. In addition, the EPR spectra obtained by continuous wave (cw) laser irradiation are different from those obtained by excimer laser irradiation. The observed β-hydrogen hyperfine coupling for pulsed laser is approximately 1 Gauss smaller than those for cw laser irradiation. The present EPR results provide firm evidence that different free radical reaction intermediates are produced for each laser mode.
Insulator-to-Metal-to-Semiconductor Transitions of One-Dimensional Bis(1,2-dione dioximato)Pt(II) Complexes at High Pressures
Authors: Shirotani Ichimin , Kawamura Akira , Suzuki Kazunaga , Utsumi Wataru , Yagi Takehiko 
Published: July 2006

Abstract
The electrical resistivities and absorption spectra of one-dimensional bis(1,2-dione dioximato)Pt(II) have been studied at high pressures. The resistivities of needle crystals of Pt(dmg)2 and Pt(bqd)2 were measured in detail under a quasi-hydrostatic pressure of up to 7 GPa. Pt(dmg)2 is an insulator with a resistivity of 1015 Ω cm, and Pt(bqd)2 is a semiconductor with 103 Ω cm at atmospheric pressure. A pressure-induced insulator (semiconductor)-to-metal transition was observed for both complexes. This transition arises from a crossing of the 5dz2 valence and 6pz conduction bands. When the pressure was further increasued, a metal-to-semiconductor transition took place at around the pressure that showed a resistivity minimum. A new pressure-induced absorption band was found in the visible region for the Pt complexes. The new band did not shift with pressure; the intensity of the band, however, increased with pressure over a narrow pressure region. The pressure-induced band may be due to intramolecular d–d transitions. The metal-to-semiconductor transition may arise from a change in the electronic states at high pressure, since no anomaly in the strucutre was observed.
Intercalation of a Triethylenetetramine-Substituted Cyclodextrin by Co(II)- and Ni(II)-Montmorillonites
Authors: Kijima Tsuyoshi , Nakazawa Hiromoto , Takenouchi Satoshi 
Published: July 2006

Abstract
The intercalation of mono[6-[(8-amino-3,6-diazaoctyl)amino]-6-deoxy]-β-cyclodextrin (CDtrien) by Co(II)- and Ni(II)-montmorillonites was examined at 25°C. At low uptakes, the CDtrien molecules in both minerals form a monolayer, 13–14 Å thick, with their cavity axes perpendicular to the silicate layers. At higher loadings, guest molecules with the same orientation form a bilayer in Co(21.8 Å thick) and Ni-montmorillonites (17.6 Å). Their thicknesses are larger than those for the Cu-and Zn-analogues, 16.1 Å, i.e. twice the molecular thickness.
Syntheses and Properties of Binuclear Manganese(III) and Manganese(IV) Complexes with 1,2,3,4-Tetrakis(salicylideneamino)-2,3-diphenylbutane
Authors: Nakamura Masaaki , Shimokawa Sayuri , Miyanaka Yuri , Huang Hu , Kai Fumiaki 
Published: July 2006

Abstract
A new dichlorodimanganese(III) and novel tetrachlorodimanganese(IV) complexes with 1,2,3,4-tetrakis(salicylideneamino)-2,3-diphenylbutane were prepared and characterized. The obtained dimanganese(IV) complex was rather stable to moisture in the solid state, but readily reduced to the corresponding dimanganese(III) complex in a methanol solution. The complexes can not be electrochemically formed as mixed valence states.
Structural and Compositional Changes of Hydrated Sodium Molybdenum Bronze by Heat Treatments in Air
Authors: Sotani Noriyuki , Eda Kazuo , Furusawa Kouichi , Hatayama Fumikazu , Takagi Sadao 
Published: July 2006

Abstract
When hydrated sodium molybdenum bronze, VD, was heated in air, dehydration as well as both irreversible and reversible phase changes took place as follows:
Na0.22(H2O)0.43H0.03MoO3.11\xrightarrow442 KNa0.21H0.03MoO3.14\xrightarrow555 KNa2Mo4O13+MoO3\xrightarrow801 Kmelt.
Structure and Polarized Spectra of cis-difluorotetraamminecobalt(III) Perchlorate, cis-[CoF2(NH3)4]ClO4
Authors: Mitsutsuka Yoshihiro , Aoyama Tomonori , Ohba Shigeru , Saito Yoshihiko , Kaneuchi Fumiko , Tsuboi Masamichi 
Published: July 2006

Abstract
The structure of cis-[CoF2(NH3)4]ClO4 has been determined by a single-crystal X-ray diffraction method. Crystals are tetragonal, space group P41 (or P43), a=7.2645(6), c=16.260(2) Å, V=858.1(2) Å3, Z=4,T=297(1) K, final R=0.052 for 970 observed unique reflections. The coordinated F and N atoms could be distinguished unambiguously from each other based on the thermal parameters. The bond distances Co–F and Co–N are 1.828(6)–1.870(5) and 1.924(7)–1.944(7) Å, respectively. The absorption spectra of the single crystals have been examined in the visible and infrared regions with polarized radiation by the use of microspectrophotometers. The 584 nm band (B1) was considered to borrow intensity from some A1 bands through vibronic coupling with some B1 vibrations, and the 504 nm band (A2 & B2) through some A2 and B2 vibrations. Two of the four ammine groups of this cobalt complex were found to give an NH3 rocking frequency (860 cm−1) higher by 50 cm−1 than the other two (at 810 cm−1). This fact has been attributed to two inter-molecular hydrogen bonds (NH···F=2.85–2.68 Å) in which the former two ammine groups are involved.
Monolayer Level Depth Profiling by Laser Induced Fluorescence Spectroscopy
Authors: Wu Xing-Zheng , Kitamori Takehiko , Teramae Norio , Sawada Tsuguo 
Published: July 2006

Abstract
Application limits of the proposed concentration depth profile using laser induced fluorescence spectroscopy based on the reciprocal principle (Bull. Chem. Soc. Jpn., 64, 755 (1991)) were investigated. Although this method has no limitations regarding film thickness and spatial resolution in the depth direction theoretically, for practical applications, they are limited by the instrumental factors. Effects of uncertainty in the observation angle measurement, which depends on the size of the detector, the mechanical precision of the rotating stage, and experimental errors in the fluorescence intensity measurement on the accuracy of the reconstructed concentration depth profile were discussed in detail. The theoretical results predicted nanometer level depth profiling with our laboratory-constructed instruments. A 29 nm thick model film sample, consisting of long chain molecular bilayers, was used to verify the theoretical analysis results. The concentration depth profile for bilayer level steps of about 5 nm was obtained under our experimental conditions. Possible improvements in this method and monolayer level depth profiling were also considered.
Spectrophotometric Determination of Tetrathionate by Its Oxidation with Iodate
Authors: Koh Tomozo , Yajima Masako 
Published: July 2006

Abstract
The conditions under which tetrathionate is oxidized stoichiometrically to sulfate by iodate have been established by investigating the reaction rate of tetrathionate with iodate in a medium containing varying amounts of sulfuric acid at room temperature and 40 °C. Tetrathionate reacted with iodate with a tetrathionate: iodate mole ratio of 3 : 7 under the conditions of the usual procedure. After a complete reaction, the iodine, formed from excess iodate by the addition of iodide, was spectrophotometrically measured as triiodide. A 14-fold chemical amplification was achieved for the determination of tetrathionate by using the proposed method, compared with the conventional methods via the sulfitolysis and cyanolysis of tetrathionate. A linear calibration graph with a negative slope was obtained over the concentration range 2.5×10−7–2.5×10−5 mol dm−3 tetrathionate (0.5–56 μg of S4O62− in 10 cm3); the relative standard deviation was 0.42% at the 1.5×10−5 mol dm−3 tetrathionate level.
Kinetics and Mechanisms of Photo-Induced Reduction of Iodine by Diamine-N-polycarboxylate Ions in an Aqueous Solution
Authors: Kimura Masaru , Ohomura Akiko , Nakazawa Fumiko , Tsukahara Keiichi 
Published: July 2006

Abstract
Although the reduction of iodine by diamine-N-polycarboxylate ions such as ethylenediaminetetraacetic acid, trans-1,2-cyclohexanediaminetetraacetic acid, N-(2-hydroxyethyl)ethylenediamine-N,N′,N′-triacetic acid, and ethylenediamine-N,N′-diacetic acid was negligible in the dark, it occurred greatly upon irradiation with visible light of an aqueous solution over the pH range 4–8. The rate of the photo-sensitized reaction was of half-order regarding both the light intensity irradiated and the concentrations of iodine, which correspond to those of the triiodide ion in the presence of excess iodide ions, and was proportional to the concentration of the diamine-N-polycarboxylate ion. Further, the rate was of half-order for concentrations of I− below 3×10−4 mol dm−3 and was of inversely half-order for concentrations of I− above 6×10−4 mol dm−3. The reaction was inhibited by radical scavengers of acrylonitrile, acrylamide, and hexaamminecobalt(III) ions. Both hydrogen ion and complex forming metal ions, such as copper(II) and zinc(II), are also strong inhibitors of the reaction. The reaction mechanism, where initiation reaction is a photo-dissociation of iodine and the reactive species is a I2\divdot radical anion, is proposed to account for the obtained results.
Selective Ring-Opening Reaction of Epoxides with Sodium Borohydride in the Presence of Cyclodextrins in Aqueous Media
Authors: Hu Ying , Uno Mitsunari , Harada Akira , Takahashi Shigetoshi 
Published: July 2006

Abstract
In the presence of cyclodextrins (CDs), the ring-opening reaction of styrene oxide with NaBH4 in aqueous media proceeded smoothly to give 1-phenylethanol with high selectivity of up to 94%, and kinetic resolution of the racemic epoxide was observed. Kinetic studies suggest the resolution based on the different reaction rates between two enantiomers included in the CD’s cavity. The reaction of epoxides such as 1,2-epoxyindan and 1,2-epoxy-3-phenylpropane are also affected by the addition of CDs to proceed smoothly with high regioselectivities.
Prediction of Product-Selectivity in an Electroorganic Process by Mathematical Modeling of Reaction Mechanism. A Rotating Cylinder Electrode System
Authors: Cheng Po-Chung , Nonaka Tsutomu , Chou Tse-Chuan 
Published: July 2006

Abstract
A mathematical mechanism model is developed for the electroreduction of carbonyl compounds in an acidic solution and shows that the formation ratio of hydrodimeric to hydromonomeric products, i.e. the product-selectivity, depends on substrate concentration, mass transfer coefficient and current density. Model calculations are in agreement with experimental results from the electroreduction of p-methylbenzaldehyde using a rotating cylinder cathode and explain a drastic effect of mass transport on the product-selectivity.