bluuebunny/crossref_metadata_2025_split huggingface dataset:
Isomeric Transition-activated 80Br and 82Br Reactions in the Gaseous CH3Br–HBr System
Authors: Kondo Kenjiro , Yagi Masuo 
Published: July 2006

Abstract
The isomeric transition(IT)-activated 80Br and 82Br reactions in the gaseous H80mBr–CH3Br and H82mBr–CH3Br systems have been compared and the roles of the charge and kinetic energy imparted to 80Br and 82Br in recombina tion reactions studied using a Kr moderator. The products CH3Br, CH2Br2, CHBr3, and CH3CH2Br in both reactions are only formed via thermal ionic processes. This differs from the 82mBrBr–CH3Br system, in which the reaction products are only formed through excess kinetic energy processes. The difference between the two reactions has been explained on the basis of the cross sections for charge neutralization and ion molecule reactions of Br+ ions as a function of the kinetic energy initially imparted to the 80Br or 82Br atoms. An isotope effect has been observed between the IT-activated 80Br and 82Br reactions with CH3Br, and attributed to the difference in the decay modes of 80mBr and 82mBr. Furthermore, the analysis of product yields due to the successive internal conversion process in 80mBr suggested that the second Auger process from the excited 80Br occurs in a liquid-like condition such as ion-clusters.
Catalysis by Mixed Oxide Perovskites. I. Hydrogenolysis of Ethylene and Ethane on LaCoO3
Authors: Ichimura Kenji , Inoue Yasunobu , Yasumori Iwao 
Published: July 2006

Abstract
Catalysis by a mixed oxide with a perovskite structure, LaCoO3, was studied for the hydrogenolysis of ethylene and ethane at temperatures 300–600 K using the hydrogen-excess mixtures. The high and stable activity was obtained by evacuating LaCoO3 at 600 K. Ethylene hydrogenolysis above 420 K proceeded consecutively via the intermediate, ethane, to produce methane, whereas only the hydrogenation to form ethane occurred below 420 K. Different temperature dependence of the rate was observed, i.e., the activation energy of −19.3 kJ·mol−1 in the range 420–600 K and 33.6 kJ·mol−1 in the range 300–420 K. The mechanistic analysis and tracer study using D2 showed that the slow step of the hydrogenation shifts, with increasing temperature, from the adsorption of hydrogen to the surface reaction between hydrogen atom and ethyl radical. The hydrogenolysis of ethane produced only methane and no ethylene was observed in gas phase; the reaction orders with respect to hydrogen and ethane pressures were, respectively, −0.5 and 1.0. In the reaction with D2, methane [D4] was the main product and an equilibrium among the formed H2, HD, and D2 was quickly established. The adsorption of ethane to undergo the rupture of the carbon-carbon bond and to form monocarbon species was proposed to be a slow step. The catalytic activities of the component oxides, La2O3 and Co2O3, were also examined for a comparison. The structure and electronic states of LaCoO3 were investigated by means of X-ray diffraction and X-ray photoelectron spectroscopy in connection with the catalytic activity. It was proposed that the hydrogenation proceeded mainly on a pair of La3+ and O2− ions, whereas the hydrogenolysis was accelerated by the Co3+ ion; the (110) plane is suggested to be the most favorable for the catalysis.
The Collection of Uranium from Sea Water with Hydrous Metal Oxide. IV. Physical Properties and Uranium Adsorption of Hydrous Titanium(IV) Oxide
Authors: Yamashita Hisao , Ozawa Yoshihiro , Nakajima Fumito , Murata Toshifumi 
Published: July 2006

Abstract
The adsorption of uranium from sea water with hydrous titanium(IV) oxide(HTO) was studied. HTO was prepared by mixing titanium(IV) chloride and aqueous ammonia at different pHs and temperatures. The fundamental property of HTO was investigated for apparent crystal size, specific surface area, and pore size. The uranium uptake of HTO was found to depend more strongly on the temperature than on the pH in the preparation. HTO prepared at higher temperatures exhibited larger pores and a higher uranium uptake. A kinetic study of the uranium adsorption revealed that the rate of adsorption was controlled by the particle diffusion. The diffusion coefficients were calculated.
The Raman Spectra of Aligned Thin Films of Nematic Liquid Crystals
Authors: Yamada Haruka , Fukumura Keiji , Tamamushi Bun-ichi 
Published: July 2006

Abstract
The Raman spectra of thin films of nematic liquid crystals, MBBA and NP-5A, have been measured for samples sandwiched between two glass (or quartz) plates, which had been pretreated in several ways. The intensities of the fundamental bands of the molecules and the polarization components of each band depend on the molecular orientation structures, such as the homogeneous and homeotropic alignments. The intensity ratio provides a semi-quantitative measure for the molecular orientation, and the Raman results are compared with those from polarizing microscopic observations and infrared spectra. The molecular orientation of the liquid crystals varies with the concentrations of surface-active agents as well as the materials used for the pretreatment of the plates. The molecular interactions, which give rise to the orientation structures, are briefly discussed.
A New Assisted Reaction in the Photodecomposition Reaction of Dibenzoyl Peroxide
Authors: Sakaguchi Yoshio , Hayashi Hisaharu , Nagakura Saburo 
Published: July 2006

Abstract
2,2′-, 2,3′-, and 3,3′-Dimethylbiphenyls were found in the photodecomposition reaction of dibenzoyl peroxide using toluene as solvent. We carried out the experiments to study the external magnetic field, oxygen scavenging, and excitation light intensity effects on their yields. It is concluded that they are produced through the dimerization of (benzoyloxy)methylcyclohexadienyl radicals. This is a new case of the assisted reaction by benzoyloxyl radical. The yields of dimethylbiphenyls were found to be affected remarkably by the small variation of the concentration of benzoyloxyl radical through the three experiments.
Thermal Decomposition of Graphite Fluoride. II. Kinetics of Thermal Decomposition of (CF)n in a Vacuum
Authors: Watanabe Nobuatsu , Koyama Satoshi 
Published: July 2006

Abstract
The rate of thermal decomposition of (CF)n prepared under several reaction conditions was measured in a vacuum. The rate was expressed by Avrami-Erofeyev’s equation of second-order for highly oriented sample and of first-order for disordered one. The apparent activation energies of the decomposition reaction were about 50 kcal/mol (1 cal=4.184 J) for the former, and about 14 kcal/mol in higher temperature region and about 100 kcal/mol in lower temperature region for the latter. Thermal decomposition of (CF)n proceeds two-dimensionally around a nucleus of carbon which is formed at the initial stage of decomposition. The rate of thermal decomposition of various samples is dependent on the number of the nucleus forming sites. The nucleation of carbon takes place on a grain boundary between two small crystallites of (CF)n. The rate of the growth of the nucleus is fast along the grain boundary but slow in other directions. The activation energy was estimated to be about 100 kcal/mol for the former and almost 0 kcal/mol for the latter.
Thermal Decomposition of Graphite Fluoride. III. Thermal Decomposition of (CF)n in Oxygen Atmosphere
Authors: Watanabe Nobuatsu , Kawamura Toshihiko , Koyama Satoshi 
Published: July 2006

Abstract
Thermal decomposition of (CF)n was carried out under an oxygen atmosphere. The decomposition temperature was found to be a decisive factor to control the decomposition mechanism and the structure of residual substances. The decomposition reaction proceeded faster in oxygen than in a vacuum at temperatures higher than 588 °C. However, it was reversed below 588 °C. The decomposition mechanism in high temperature region was similar to that in a vacuum. The ESCA spectra of residual substances prepared above 588 °C indicated the presence of carbon atoms which were not bonded with fluorine, namely the nuclei comprised of carbon still remained even in oxygen. The rate of the weight decrease was larger in oxygen than in a vacuum because of the reaction of carbon nuclei, which was formed by thermal decomposition, with oxygen. On the other hand, it considerably decreased below 588 °C, where no nuclei was found for any sample.
The J-aggregate 5,5′,6,6′-Tetrachloro-1,1′-diethyl-3,3′-bis(4-sulfobutyl)benzimidazolocarbocyanine Sodium Salt in Aqueous Solution
Authors: Makio Shigetoshi , Kanamaru Nobuaki , Tanaka Jiro 
Published: July 2006

Abstract
The aggregation of the title dye in a dilute alkaline aqueous solution is investigated at 283–303 K by measuring the electronic absorption spectra. The association number is estimated to be 8, the heat of formation and the entropy change for the association are found as ΔH=−91.5 kcal mol−1 (1 cal=4.184J) and ΔS=−139.3 cal K−1 mol−1, respectively. The structure of the octamer is discussed from a view of spectral shift, intermolecular force and the crystalline structural data. The lifetimes, quantum yields and polarization of fluorescence are investigated on the monomeric and the J-aggregate state of the dye. The energy transfer between several J-aggregate units is indicated in the excited state.
Possible Role of Denatured Albumin in Formation of “Heat-resistant” Serum Albumin
Authors: Terada Hiroshi , Watanabe Kazuhiko , Kametani Fujio 
Published: July 2006

Abstract
Studies with the probe dye 2-(4-hydroxyphenylazo)benzoic acid, which can detect small conformational differences in serum albumin, showed that the conformation of “heat-resistant” serum albumin (form N′) was not constant, but depended on the heating temperature, becoming similar to that of the denatured monomer as the heating temperature was increased from 55 °C to 70 °C in buffer of pH 7.0. Denatured albumin was suggested to protect native serum albumin from full denaturation. In the presence of denatured albumin, native albumin was found to undergo only a slight conformational change to give the N′ form. This protective effect may explain why a constant amount of serum albumin remains as “heat-resistant” serum albumin even after prolonged heating.
Singlet Energy Transfer in p-Terphenyl Crystal Doped with Tetracene
Authors: Shinohara Hiroyuki , Kotani Masahiro 
Published: July 2006

Abstract
The transfer of singlet energy in p-terphenyl crystal was measured as a function of the dopant (tetracene) concentration and the temperature. The simple hopping model yields a value of 3×10−14 s. This value is believed to be correct within a factor of 5. In the low temperature phase of the crystal, the energy transfer is temperature dependent with an activation energy of 66 cm−1 in undeuterated p-terphenyl and 90 cm−1 in perdeuterated p-terphenyl. It seems probable that in the low temperature phase the freedom of the conformational change of the molecule plays an important role in the energy migration.
Nitrogen Determination by Pyrolysis Using Steam. I.
Authors: Nomura Akira , Morita Yazaemon , Kogure Yukitoshi 
Published: July 2006

Abstract
Pyrolysis of nitrogen compounds with use of steam and FeCl3–Al2O3 catalyst was investigated in detail in order to develop a new method for nitrogen determination. The catalyst was prepared by mixing an aqueous FeCl3 solution and porous active Al2O3 for column chromatography and drying the mixture. A sample solution containing nitrogen was added to the catalyst in a boat and was then covered with an additional catalyst after removal of the solvent, leaving the sample adsorbed on the catalyst. The boat was then inserted into a pyrolysis tube, the sample being pyrolyzed in the presence of steam also used as carrier gas. The nitrogen in the sample converted into ammonia by the pyrolysis reaction was determined by titration after steam distillation under alkaline conditions. The nitrogen compounds except for N–O and N–N bonded compounds were converted quantitatively into ammonia by the pyrolysis under optimum conditions. The reaction was applied to the determination of nitrogen in various compounds.
Synthesis and Characterization of Metal Complexes with Schiff Bases Obtained from N,N′-Bis(3-aminopropyl)piperazine and Salicylaldehyde Derivatives
Authors: Kuma Hiro , Yamada Shoichiro 
Published: July 2006

Abstract
Cobalt(II), nickel(II), cobalt(III), manganese(III), and iron(III) complexes have been synthesized with Schiff bases (abbreviated as X-sal-prpi) derived from N,N′-bis(3-aminopropyl)piperazine and salicylaldehyde derivatives. On the basis of electronic spectra, infrared spectra, and magnetic data, the structures of the metal complexes are discussed. Complexes of the type CoII(X-sal-prpi) are five-coordinated, and MIII(X-sal-prpi)ClO4 consist of six-coordinated [M(X-sal-prpi)]+ and free ClO4− ions, the ligands X-sal-prpi being quinquidentate in the former and sexadentate in the latter.
Synthesis of Indeno[1,2-d]azepine Derivatives
Authors: Kimura Masaru , Satake Kyosuke , Yonemori Shigeaki , Morosawa Shiro 
Published: July 2006

Abstract
4-Ethoxyindeno[1,2-d]azepine(18) and 10-bromo-4-ethoxyindeno[1,2-d]azepine were prepared by O-ethylation of indeno[1,2-d]azepin-4-ol(12ab) and 10-bromoindeno[1,2-d]azepin-4-ol(13ab) with Et3OBF4 in 62 and 69% yields, respectively. 12ab was obtained by bromination of 1,2,3,4,5,10-hexahydro-4-indeno[1,2-d]azepine(3) or 1,2,3,4-tetrahydroindeno[1,2-d]azepin-4-one with NBS, and subsequent dehydrobromination of the corresponding bromide formed in situ on basic alumina in 10% yield. When the bromination time was over 20 h, only 13ab was isolated in 20% yield. Direct dehydrogenation of 3 with DDQ gave 10-chloroindeno[1,2-d]azepin-4-ol in 27% yield. The NMR and electronic spectra of 18 indicated the presence of a fully conjugated 14-pi ring system in it. We also investigated the possibility for dehydrogenation of 3-ethoxycarbonyl-1,2,3,4,5,5a,10,10a-octahydroindeno [1,2-d] azepin-10-one.
Photochemical Ethoxycarbonylation, Formylation, and Ethoxymethylation of Ruthenocene in Ruthenocene–Polychloromethane–Ethanol Systems
Authors: Sugimori Akira , Matsui Masaru , Akiyama Takeo , Kajitani Masatsugu 
Published: July 2006

Abstract
Similar to ferrocene the UV-irradiation of ruthenocene–polychloromethane–ethanol systems brings about substitution (ethoxycarbonylation for CCl4, formylation for CHCl3, and ethoxymethylation for CH2Cl2) and oxidation. When CHCl3 and CH2Cl2 are used, substitution is dominant. In the irradiation of ruthenocene–CCl4–ethanol system, [Ru(C5H5)2]+[RuCl4]− and cyclopentenes substituted by chlorine and trichloromethyl are obtained. The excitation of the CT-complex between ruthenocene and polychloromethane initiates the reaction.
One-step Synthesis of 3-(Dialkylamino)indolizines by the Palladium-catalyzed Reaction of α-Bromopyridine, Propargyl Alcohol, and Secondary Amine
Authors: Ohsawa Akio , Abe Yoshihito , Igeta Hiroshi 
Published: July 2006

Abstract
3-(Dialkylamino)indolizines were synthesized in one step by the reaction of 2-bromopyridine, propargyl alcohol, and secondary amines in the presence of Pd(PPh3)2Cl2–CuI as a catalyst. 3-(2-Pyridyl)-2-propyn-1-ol and 3-(2-pyridyl)acrylaldehyde were suggested to be intermediates of the reaction. 3-Dialkylamino derivatives of pyrrolo[1,2-a]quinoline, pyrrolo[2,1-a]isoquinoline, and pyrrolo[1,2-b]pyridazine were obtained from the corresponding α-haloazaaromatics in a similar way.
Cyclization of Isothiosemicarbazones. III. Formation of Thiazolines and Thiazoles through Potential Sulfonium Salts from N,S-Disubstituted Isothiosemicarbazones
Authors: Yamazaki Chiji 
Published: July 2006

Abstract
The reaction of 3,4-disubstituted isothiosemicarbazones with α-bromo ketones led to the formation of 4-thiazoline derivatives, the substituents on the sulfur atom being cleaved as bromides. They are identical with the compounds obtained by the condensation of the corresponding thiosemicarbazones, having significantly lower E⁄Z ratios in certain products than in those from thiosemicarbazones. The yields of 4-thiazolines widely vary with the substituents on the N-4 and the sulfur atom in the isothiosemicarbazones and also with halo ketones. A mechanism has been suggested which deals with a sulfonium-formation and dissociation process at the apparently less nucleophilic sulfur atom of isothiosemicarbazone. The mechanism might explain the effect of changes in the substituents on the sulfur atom upon the yield of 4-thiazolines, the higher contents of (Z)-4-thiazoline from (E,E)-2,6-dichlorobenzaldehyde 3-allyl-4-methylisothiosemicarbazone, and the inertness or less reactivity of anisaldehyde 2,3-dimethylisothiosemicarbazone and salicylaldehyde 3-allyl-4-phenylisothiosemicarbazone. Differentiation between isomeric thiazole and 4-thiazoline compounds was also described.
Studies on Heteropentalenes. II. Cycloaddition of Imidazo[2,1-b]thiazoles, Thiazolo[3,2-a]benzimidazole, and Imidazo[2,1-b]benzothiazole with a Reactive Acetylenic Ester
Authors: Abe Noritaka , Nishiwaki Tarozaemon , Komoto Noriko 
Published: July 2006

Abstract
Cycloaddition of imidazo[2,1-b]thiazoles with dialkyl acetylenedicarboxylate follows dual courses depending on the polarity of the solvent, affording pyrrolo[2,1-b]thiazoles in an aprotic nonpolar solvent, or imidazo[1,2-a]pyridines and imidazo[3,4-a]pyridines, together with thiophenes, in an aprotic polar solvent. Thiazolo[3,2-a]benzimidazole and imidazo[2,1-b]benzothiazole were also found to react with the acetylenedicarboxylate to give pyrido[1,2-a]benzimidazole and pyrrolo[2,1-a]benzothiazole, respectively. The reactions would be accounted for in light of the Diels-Alder reaction in an aprotic nonpolar solvent and the 1,4-dipolar cycloaddition in an aprotic polar solvent.
Coordinative Role of Alkali Cations in Organic Reactions. V. The Perkin Reaction
Authors: Poonia Narinder S , Sen Swagata , Porwal Prafulla K , Jayakumar A 
Published: July 2006

Abstract
The Perkin condensation of benzaldehyde (PhCHO) and acetic anhydride (Ac2O) in the presence of an alkali acetate (M+OAc−) involves extensive participation of M+ and takes place best with K+OAc−. Employing an excess of meticulously dehydrated K+OAc−, a record high yield of cinnamic acid (≈75%) can be obtained in a 60 min reaction. The product of the reaction before hydrolysis is not PhCH=CHCOOCOCH3 as usually believed but potassium cinnamate plus K+(OAc, HOAc)−. Conductometric solution stability studies on M+-ligand (M+=Na+ and K+; Ligand=PhCHO, o-NO2C6H4CHO, o-HOC6H4CHO) systems in 2-propanol show that stability sequences for PhCHO and o-NO2C6H4CHO are NaOAc&lt;KOAc and KOAc&lt;NaOAc, respectively. These are in line with the catalytic efficiency these salts displayed during the condensation reaction, o-HOC6H4CHO, for which the Perkin condensation is extremely poor, is practically non-complexing with M+OAc− in 2-propanol.
Configuration Analysis and Electronic State Properties. III. Ten-π-electron Systems
Authors: Buemi Giuseppe 
Published: July 2006

Abstract
The electronic state properties of the nonbenzenoid hydrocarbons fulvalene, heptatriafulvalene, dimethylenebenzocyclobutene, [5]radialene, 8-vinylheptafulvene, 1,2-benzofulvene and 2,3-benzofulvene have been studied by means of MIM and PPP-configuration analyses. The resonance integrals evaluated by Kon’s equation are satisfactory for the MIM method but not for PPP. On the whole the general spectral trend is fairly predicted by both approximations, the wavefunction composition being in line with the first electronic transitions. The lower energy electronic transitions are found to be a mixture of locally excited and charge transfer states while those computed at higher energy have prevailing charge transfer character.
Purification of Methylthymol Blue and Methylxylenol Blue by High-Performance Liquid Chromatography
Authors: Nakada Shoji , Yamada Mutsuo , Ito Tasuku , Fujimoto Masatoshi 
Published: July 2006

Abstract
Relatively large amounts of 3,3′-bis[bis-(carboxymethyl)aminomethyl]thymolsulfonphthalein (Methylthymol Blue, MTB) and 3,3′-bis[bis(carboxymethyl)aminomethyl]-p-xylenolsulfonphthalein (Methylxylenol Blue, MXB) are easily purified by high-performance liquid chromatography (HPLC).
The Synthesis of 1,3,5-Thiadiazinylium Salts
Authors: Shibuya Isao 
Published: July 2006

Abstract
1,3,5-Thiadiazinylium salts were synthesized in good yields by the reaction of N-acyl imidoyl chlorides with thioamides or the treatment of 4H-1,3,5-thiadiazines with trityl salts.
A 13C NMR and CNDO/2 Calculation Study of the Transannular Interaction in [2.2]Metacyclophanes
Authors: Tokita Kazushi , Kondo Shoichi , Mori Nobuo 
Published: July 2006

Abstract
The substituent effects on the chemical shifts and CNDO/2 total electron densities of the facing aryl carbons, C-8 and C-16, in [2.2]metacyclophanes are reported.
The Reaction of Thiocumulenes with Fulvene
Authors: Saito Takao , Musashi Teruhiko , Motoki Shinichi 
Published: July 2006

Abstract
S-(9-Fluorenylidene)-N-(p-tolylsulfonyl)sulfimide and bis(p-tolylsulfonyl)sulfur diimide reacted as 1,3-dipoles with fulvenes to form (2+3)cycloadducts.
Michael Addition of p-Styrenesulfinate to Acrylic Compounds
Authors: Kamogawa Hiroyoshi , Kusaka Hiroyuki , Nanasawa Masato 
Published: July 2006

Abstract
Acrylic compounds CH2=CHX, where X represents -COOH, –CONH2, –CN, and –COOCH2CH2OH, were converted into the corresponding 3-(p-vinylphenylsulfonyl)- and 3-(p-tolylsulfonyl)propionic acids and their derivatives by the Michael addition with p-styrene- and p-toluenesulfinates, respectively, in the presence of acid as proton source.
Studies on Biologically Active Pteridines. V. Synthesis of (6S)-5,6,7,8-Tetrahydro-1,3,5,6-tetramethyllumazine
Authors: Sugimoto Takashi , Matsuura Sadao 
Published: July 2006

Abstract
(+)-5,6,7,8-Tetrahydro-1,3,5,6-tetramethyllumazine, a compound derived from enzymically reduced (−)-5,6,7,8-tetrahydro-6-methylpterin, was shown to be of (S)-configuration at the C-6 chiral center by a synthesis, which was performed by condensation of 5-bromo-6-chloro-1,3-dimethyluracil and (2S)-1-amino-2-(methylamino) propane. The structure of the condensation product was determined unequivocally by an independent synthesis using a regioselective methylation of 5,6,7,8-tetrahydro-1,3,6-trimethyllumazine.
Thermodynamic Study on Mixed Monolayers of Butyl Eicosanedioate and Tetradecanoic Acid
Authors: Hayami Yoshiteru , Yano Takeshi , Motomura Kinsi , Matuura Ryohei 
Published: July 2006

Abstract
In order to clarify the behavior of mixed monolayers of butyl eicosanedioate and tetradecanoic acid, the surface pressure was measured as a function of mean area at various compositions and temperatures. Four types of phase transition were observed. By use of the thermodynamic treatment previously developed, the apparent molar entropy and energy changes associated with the phase transition were evaluated. It was concluded on thermodynamic considerations that the butyl eicosanedioate and tetradecanoic acid monolayers are immiscible in condensed states and their phase diagram has a two-dimensional eutectic point.