bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Formation of Electronically Excited Fragments by the Electron Impact of Furan and Related Five-membered Heterocycles
Authors: Tokue Ikuo , Ikarashi Masami , Takizawa Sadachika , Ito Yoshio 
Published: July 2006

Abstract
In the wavelength region of 200–600 nm, photoemissions from electronically excited H, CH, C2, and CS (only from thiophene and tetrahydrothiophene) were observed when furan, tetrahydrofuran, thiophene, and tetrahydrothiophene were excited by electron impact (0–70 eV). Hydrogen atoms (n=4) and CH(A2Δ) radicals were produced from these five-membered heterocycles via single collision excitations, while CS(A1Π) radicals from thiophene and tetrahydrothiophene were partly formed in secondary processes. The appearance potentials for the hydrogen Balmer β and the CH(A2Δ-X2Π) bands from these five-membered heterocycles are determined, and the dissociation processes forming H(n=4) and CH(A) are discussed.
Chemiluminescence from Reactions of N2*(A3Σu+) with Solid Organic Compounds at 77 K
Authors: Mitsumori Kenichi , Hiraoka Kenzo 
Published: July 2006

Abstract
The luminescence from reactions of N2(A3Σu+) with solid benzene, toluene, hexane, cyclohexane and those doped with biacetyl at 77 K has been investigated. For benzene, a broad band appeared in the range of 350–550 nm whose radiative lifetime was determined to be 2.5 s. This band was largely eliminated by addition of a small amount of biacetyl, indicating the participation of an intermediate excited state in solid benzene, i.e. triplet excitons. The emitter of the broad band was tentatively assigned to reaction products, possibly benzene isomers. For toluene, a strong appearance of benzyl radical emission was observed. With an addition of biacetyl, the elimination of benzyl emission and a strong growth of biacetyl phosphorescence were observed as for the benzene/biacetyl system. With an increase of biacetyl concentration, a remarkable red shift were observed for biacetyl phosphorescence, while no shift was observed for benzyl emission, indicating the difference of the solvent effect for these electronic transitions. No luminescence was observed for solid hexane and cyclohexane.
Magnetic-superexchange Interactions of Uranium(IV) Chloride-addition Complexes with Amides. I
Authors: Miyake Chie , Hinatsu Yukio , Imoto Shosuke 
Published: July 2006

Abstract
Studies of magnetic susceptibility, χ, from 300 to 2 K on seventeen UCl4–amide complexes showed that six complexes had maxima in χ between 155 and 82 K. This unusual magnetic behavior occurred only with N-methyl or ethyl-substituted amide complexes. Infrared and chemical evidence indicates that these six complexes probably have dimeric structure, in which two U(IV) ions are bridged by the amide ligands. Assuming a dimer structure and a two-spin Heisenberg model with −2Jex of about 90 cm−1 for the dimer, the magnetic susceptibilities for the six complexes were calculated in good agreement with the experimental results in the temperature region of the maxima in χ.
Preparation of Trifluoronitrosomethane
Authors: Umemoto Teruo , Tsutsumi Hideo 
Published: July 2006

Abstract
Trifluoronitrosomethane was prepared in a good yield by pyrolysis of nitrosyl trifluoroacetate in a flow of nitrogen monoxide at 190 °C using refluxed perfluorotributylamine as a diluent.
Palladium-catalyzed Reaction of Isoprene with Water in Presence of Carbon Dioxide and Base
Authors: Inoue Yoshio , Sato Michio , Satake Masaki , Hashimoto Harukichi 
Published: July 2006

Abstract
Palladium(0)-catalyzed reaction of isoprene with water was enhanced by the presence of carbon dioxide and a base to give dimethyloctadienols. The same catalyst was found to dehydrate the dimethyloctadienols to afford the corresponding dimethyloctatrienes. The effect of acidity of water on the isoprene-water reaction was also studied.
Acid Decomposition of 5-Amino-1-vinyl-4,5-dihydro-1H-1,2,3-triazoles. A Novel Formation of 1-Amino-2-azabutadienes
Authors: Ito Masato M , Nomura Yujiro , Takeuchi Yoshito , Tomoda Shuji 
Published: July 2006

Abstract
Acid decomposition of 4-alkyl-5-dialkylamino-1-vinyl-4,5-dihydro-1H-1,2,3-triazoles gave N1,N1-dialkyl-N2-vinylalkanamidines, which have 2-aza-1,3-butadiene skelton, in fair yields.
The Reaction of O-Silylated Enolates of Carboxylic Esters and of Lactones with Aminomethyl Ethers Catalyzed by ZnCl2
Authors: Oida Tatsuo , Tanimoto Shigeo , Ikehira Hideyuki , Okano Masaya 
Published: July 2006

Abstract
It was found that the reaction of O-silylated enolates of carboxylic esters and of lactones with aminomethyl ethers proceeds smoothly under a catalytic action of zinc chloride to afford the corresponding α-aminomethylated carboxylic esters or lactones, except only one case using O-silylated enolate of δ-valerolactone, in which the resultant α-aminomethyl-δ-valerolactone is somewhat unstable and undergoes decomposition, leading to the production of α-methylene-δ-valerolactone.
Structures of the [4+2] Bicyclic Adducts from the Diels-Alder Reaction of Methyl Coumalate with Isoprene
Authors: Matsui Takanao , Inoue Takeshi , Nakayama Mitsuru , White James D 
Published: July 2006

Abstract
The preparation of 9- and 8-methyl-9-iodo-3-oxo-2-oxabicyclo[4.4.0]dec-4-ene-6,8-carbolactone and 8-methyl-3-oxo-2-oxabicyclo[4.4.0] deca-4,9-diene-6,8-carbolactone from the adducts (2a and 2b) of methyl coumalate with isoprene confirmed the structures of the regioisomers, 2a and 2b.
Electronic Absorption Spectra and Geometry of Molecular Ions Generated from Stilbene and Related Compounds. III. Radical Ions of (Z)-Stilbene and Its α,β-Dialkyl Derivatives
Authors: Suzuki Hiroshi , Ogawa Keiichiro , Shida Tadamasa , Kira Akira 
Published: July 2006

Abstract
The radical ions of (Z)-stilbene and its α,β-dialkyl derivatives were produced by γ-ray irradiation of the parent compounds in frozen matrices at 77 K, and their geometries were investigated by electronic absorption spectroscopy. While the relaxed geometries of the radical ions of (Z)-stilbene are probably similar to that of the neutral molecule, those of the radical ions of the α,β-dialkyl derivatives are appreciably different from those of the neutral molecules: The torsion angle of the central ethylenic bond is distinctly larger and that of each C–Ph bond is probably smaller in the radical ions than in the neutral molecules. On illumination the radical ions of (Z)-stilbene isomerize to the E isomers, but those of the α,β-dialkyl derivatives do not. A mechanism of the photoisomerization is proposed, and an interpretation of the difference in the photochemical behavior between the unsubstituted stilbene radical ions and the α,β-dialkyl derivatives is given.
The Reactions of the Singlet NH Radicals with C4 Olefins in the Liquid Phase
Authors: Hamada Jun-ichi , Tsunashima Shigeru , Sato Shin 
Published: July 2006

Abstract
The reactions of NH radicals with C4 olefins, trans- and cis-2-butenes, 1-butene, and isobutene, were investigated by the photolysis of hydrogen azide in the liquid olefin at 0 °C and at the temperature of Dry Ice–methanol. Except for nitrogen and ammonia, amines and aziridines were found to be formed in good yield. 2-Butene-1-amine and trans-2,3-dimethylaziridine from trans-2-butene, 2-butene-1-amine and cis-2,3-dimethylaziridine from cis-2-butene, 3-butene-1- and 2-amines and 2-ethylaziridine from 1-butene, and 2-methyl-2-propene-1-amine and 2,2-dimethylaziridine from isobutene. These product formations were successfully explained by the insertion into the C–H bond and the addition to the double bond of olefin by the singlet NH radicals. In the case of 2-butene, no isomerized aziridine formation was observed. This result suggested that the triplet NH radicals rarely add to the double bond of olefin.
Brφnsted Relation for Hydrogen→Deuterium Exchange Reactions of Imidazole-bearing Molecules with Amino Groups
Authors: Endo Toshiya , Shimada Ichio , Inagaki Fuyuhiko , Miyazawa Tatsuo 
Published: July 2006

Abstract
The base-catalyzed hydrogen→deuterium exchange rates of the imidazole C-2 protons were measured for the imidazole-bearing molecules with amino groups (N2H2·Im) in 2H2O at various pH. From the pH dependences of the pseudo-first-order rate constants, the second-order rate constants were obtained for the N2H3+·Im2H+ species and for the equilibrium mixtures of the N2H2·Im2H+ and N2H3+·Im species. For both the N2H3+·Im2H+ and N2H2·Im2H+ species, the second-order rate constants and microscopic dissociation constants of the imidazolium rings were found to satisfy the Brφnsted relation, with concomitant estimation of the abundance ratio of the N2H2·Im2H+ and N2H3+·Im species. This abundance ratio was compared with that estimated from the pH dependence of proton chemical shifts.
Volumetric Study on the 1,3-Dipolar Cycloaddition Reaction of Diazodiphenylmethane with Several Olefins
Authors: Yoshimura Yosuke , Osugi Jiro , Nakahara Masaru 
Published: July 2006

Abstract
A high pressure kinetic study was made of the 1,3-dipolar cycloaddition reaction of Ph2CN2 with dimethyl maleate (DMM), dimethyl fumarate (DMF), methyl acrylate (MA), maleonitrile (MN), fumaronitrile (FN), and acrylonitrile (AN) in toluene at 25 °C. The activation volumes (ΔV\eweq) at 1 bar obtained for DMM, DMF, MA, MN, FN, and AN are −23.4±0.5, −22.3±0.2, −19.8±0.4, −21.5±0.6, −21.0±1.1, and −23.9±0.5 cm3 mol−1, respectively. The reaction volume (ΔV) for the reaction between Ph2CN2 and DMM was determined dilatometrically by taking advantage of supersaturation of the cycloadduct in solution; ΔV=−24.5±0.5 cm3 mol−1 and ΔV\eweq⁄ΔV=0.955. The present volumetric information coupled with a kinetic analysis shows that Firestone’s biradical mechanism is not the case; the concerted mechanism is supported. The experimental result is compared with that of a recent ab initio molecular orbital calculation with respect to the activation and reaction volumes.
Pressure and Temperature Effects on Octahedral-Tetrahedral Equilibria in Pyridine Solutions of Some Cobalt(II) Halides
Authors: Kojima Kazuo , Saida Minoru , Donoue Masami , Matsuda Jiro 
Published: July 2006

Abstract
The visible absorption spectra of CoX2 (X=Cl, Br) in pyridine solutions have been measured in the ranges 1 bar—3 kbar at room temperature, and ≈4—≈70 °C at 1 atm. The equilibrium, [CoX2(py)2](tetrahedral)+2py\ightleftharpoons[CoX2(py)4](octahedral), is found to be followed over these pressure and temperature ranges. High pressure favors the octahedral species, with the volume changes, −41 cm3/mol for the chloride and ≈−30 cm3/mol for the bromide at 1 atm. The pressure dependence of the volume change is less for the bromide than for the chloride. High temperature, however, favors the tetrahedral species, with the heats of reaction, 57.3 and 60.7 kJ/mol for the chloride and the bromide, respectively. Some discussions on both the effects are also presented.
Phase Equilibria in the Nd2O3–V2O3–V2O5 System at 1200 °C
Authors: Kitayama Kenzo , Mizokuchi Chikaaki , Katsura Takashi 
Published: July 2006

Abstract
Phase equilibria in the Nd2O3–V2O3–V2O5 system were established at 1200 °C by changing the oxygen partial pressures from −0.68 (air) to −12.50 in terms of logPO2. In this system, VnO2n−1 (n=2–7), VO2, Nd2O3, NdVO3, NdVO4, 0.81Nd2O3·0.19V2O5 (Nd1.62V0.38O3.38, A), and 3Nd2O3·V2O5 (Nd3VO7, B) were stable under the present experimental conditions. Compounds with Nd2O3/V2O5 mole ratios of 6/1 and 2/1 were not found under the present experimental conditions. Compounds A, Nd3VO7, NdVO3, and NdVO4 have nonstoichiometric compositions. The pattern of the phase diagram is different from those of other Ln2O3–V2O3–V2O5 systems that have previously been established by us. On the basis of the phase diagram, the Gibbs energies of the reactions:
(1) 31⁄50Nd2O3+19⁄50NdVO3+19⁄100O2=Nd1.62V0.38O3.38
(2) 50⁄31Nd1.62V0.38O3.38+12⁄31NdVO3+6⁄31O2=Nd3VO7
(3) NdVO3+1⁄2O2=NdVO4
were determined to be −61.4, −47.4, and −128.9 kJ respectively. In the Nd2O3–V2O3 system, only NdVO3 is stable under the present experimental conditions.
Kinetic Study of the Oxidation of Formate by Iodine in Micellar Solutions of Alkyltrimethylammonium Chlorides
Authors: Hayakawa Katumitu , Kanda Mitsuo , Satake Iwao 
Published: July 2006

Abstract
The spectrophotometric study was made of the oxidation of formate by iodine in micellar solutions of decyl- and dodecyltrimethylammonium chlorides. In the presence of the cationic surfactant micelles, the reaction was found to take place only at the micellar surface according to the same mechanism as in water. The experimental second-order rate constant rose steeply to a maximum at the critical micelle concentration and then decreased monotonously with increasing surfactant concentration. A tentative estimation based on a charged-phase separation model led to the true second-order rate constant in micellar phase of 0.03–0.07 mol−1 dm3 s−1 at 30 °C, which is comparable with that in water. Thus the observed rate enhancement in cationic surfactant solutions can be interpreted in terms of an increase in surface concentration of the formate ion arising from an electrostatic interaction with the micellar ion. The micellar effects on the formation constant of triiodide ion are also discussed.
Mechanism of the Photochemical and Thermal Wolff Rearrangement of 2-Diazo-1,3-dicarbonyl Compounds
Authors: Tomioka Hideo , Hayashi Norihiro , Asano Tsuneo , Izawa Yasuji 
Published: July 2006

Abstract
Thermolysis and photolysis of 2-diazo-1,3-dicarbonyl compounds were investigated as a function of methanol concentration. As the methanol concentration decreased, methyl group migration increased concomitant with the suppression of O–H insertion into methanol, whereas aryl group migration was essentially unaltered with the methanol concentration. The results are interpreted as indicating that aryl migration occurs directly from the excited state of diazo compounds, but that met hyl migration takes place in the singlet carbene in competition with O–H insertion.
Conversions of Carbonyl Compounds via Their Polymeric Sulfonylhydrazones into Alkenes, Alkanes, and Nitriles
Authors: Kamogawa Hiroyoshi , Kanzawa Asami , Kadoya Masahiro , Naito Takeshi , Nanasawa Masato 
Published: July 2006

Abstract
Reins consisting of cross-linked poly(styrene-divinylbenzene) matrices functionalized with hydrazinosulfonyl groups react with aldehydes and ketones to form the sulfonylhydrazone derivatives. The extent of the reaction is sensitive to the type of resin and the bulk of the carbonyl compound. When heated strongly under alkaline conditions, the sulfonylhydrazones release the corresponding alkenes; upon the NaBH4 or LiAlH4 treatment, they also release the corresponding alkanes; and, upon refluxing in methanol with potassium cyanide, they release nitriles containing one additional carbon atom.
Coenzyme Models. 33. Evidence for Retro-acyloin Condensation as Catalyzed by Thiazolium Ion and Cationic Micelle. Oxidative Trapping of the “Active Aldehyde” Intermediates by Flavin
Authors: Shinkai Seiji , Hara Youichiro , Manabe Osamu 
Published: July 2006

Abstract
N-Hexadecylthiazolium bromide(HxdT) in the CTAB micelle, which is known as an excellent catalytic system for acyloin condensation of aldehydes, catalyzes the reverse reaction (i.e., retro-acyloin condensation) to give aldehydes from α-ketols via the active aldehyde intermediates. The existence of the novel, HxdT-mediated process was proposed on the basis of an experimental discovery that flavin (3-methyltetra-O-acetylriboflavin: MeFl), which is capable of oxidatively trapping the active aldehyde intermediates, is reduced by α-ketols such as acetoin and 3-hydroxy-3-methyl-2-butanone in the micellized HxdT solution. It was further substantiated by detection of acetaldehyde in the final reaction mixture. Based on the disappearance rate of the absorbance of MeFl, we spectrophotometrically estimated the rate constants for the retro-acyloin condensation. Similarly, biacetyl, the monohydrated species of which is analogous to α-ketol, afforded acetaldehyde and acetic acid in the micellized HxdT solution, the rate constant being greater by factors of 102–103 than those for α-ketols. The relevance of the retro-acyloin condensation to biological systems (e.g., the mechanism of transketolase catalysis) is discussed.
The Hydroxylation of β-Terpineol and Its Acetate with the Cultured Cells of Nicotiana tabacum
Authors: Suga Takayuki , Lee Ym Sook , Hirata Toshifumi 
Published: July 2006

Abstract
The biotransformation of c-4-p-menth-8(9)-en-r-l-ol (β-terpineol) and its acetate with the cultured suspension cells of Nicotiana tabacum were tested. It was found that the cultured cells have the ability to hydroxylate not only the allylic positions of the C–C double bond of these substrates, but also their terminal carbon-carbon double bond. The hydroxylation at the 4-position of their allylic positions was stereospecific, affording a trans-1,4-diol.
The Ion-exchange Chromatography of Imino Derivatives of Glycine
Authors: Kawashiro Katsuhiro , Morimoto Shiro , Yoshida Hideyuki 
Published: July 2006

Abstract
The resolution of the six imino derivatives of glycine (Gly) by ion-exchange chromatography is described. The imino compounds included iminodiacetonitrile (1), iminodiacetamide (2), iminodiacetic acid (3), α-(cyanomethylamino)acetamide (4), α-(cyanomethylamino)acetic acid (5), and α-(carbamoylmethylamino)acetic acid (6). A mixture of 1–6 was chromatographed along with Gly, glycinamide, aminoacetonitrile, and NH3 with an automatic amino acid analyzer using Aminex A-4 resin column (0.25φ×50 cm) and sodium citrate buffers. When the initial buffer of pH 3.25 was changed to pH 6.50 15 min after beginning the analysis, these ten components were completely resolved. The analysis was completed in about 4.5 h. The stability of 1, 4, and 5 in aqueous media at room temperature was also studied.
Anion-catalyzed Phase-transfer Catalysis. I. Application to Diazo-coupling Reactions
Authors: Iwamoto Hidetoshi , Yoshimura Masaji , Sonoda Takaaki , Kobayashi Hiroshi 
Published: July 2006

Abstract
Anion-catalyzed phase-transfer catalysis was evidenced in the diazo-coupling reactions of the arenediazonium ion with a range of diazophile components in liquid-liquid- and liquid-solid two-phase systems. The tetrakis[3,5-bis(trifluoromethyl)phenyl]borate ion was effective as an anionic catalyst to accelerate the reactions. Comparisons of the reaction rates in the two-phase system with those in solution systems indicated that the acceleration was due to the increased activity of the cationic reagent, partly by solubilization and partly by the dehydration of such cationic species in the nonpolar organic phase.
Restricted Rotation Involving the Tetrahedral Carbon. XLVII. The “Positive” and the “Negative” Buttressing Effects on the Rotational Barriers in 9-(1,1-Dimethyl-2-phenylethyl)-1-halotriptycenes
Authors: Yamamoto Gaku , Suzuki Masahiko , Oki Michinori 
Published: July 2006

Abstract
9-(1,1-Dimethyl-2-phenylethyl)-1,2,3,4-tetrahalotriptycenes (halogen=F, Cl, and Br) were synthesized and the kinetic studies of the rotational isomerization were made. The obtained data were compared with those for the corresponding 1-halo derivatives. The equilibrium constants (±sc⁄ap) for the tetrahalo compounds are smaller than those for the respective monohalo counterparts. The tetrafluoro compound isomerizes twice slower than the monofluoro one at 240 °C, showing the “positive” buttressing effect. Contrarily, the tetrachloro and the tetrabromo compounds isomerize 13 and 100 times, respectively, faster than the corresponding monohalo compounds at 175 °C, exhibiting the “negative” buttressing effect. These intriguing phenomena are discussed in terms of the molecular deformation in these congested compounds, which affects both the ground state and the transition state for rotation.
Acyl Transfer from S-Monoacyldihydrolipoamide to Benzylamine in the Presence of Oxidizing Agents
Authors: Nambu Yoko , Endo Takeshi , Okawara Makoto 
Published: July 2006

Abstract
Acyl transfer reaction from N-benzyl-8-S-(p-nitrobenzoyl)dihydrolipoamide to benzylamine was enhanced with oxidizing agents such as cobalt(II) ion or a soluble flavin under an oxygen atmosphere or with di-4-pyridyl disulfide, accompanied by the formation of N-benzyllipoamide.
31P NMR Study of Active Species for Ethylene Dimerization in σ-Aryl Nickel Complex–AgClO4
Authors: Ishimura Yoshimasa , Maruya Ken-ichi , Nakamura Yoshiyuki , Mizoroki Tsutomu , Ozaki Atsumu 
Published: July 2006

Abstract
[NiBr(σ-C6F5)(PPh3)2] and [NiCl(σ-C6Cl5)(PPh3)2] are active for ethylene dimerization in the presence of AgClO4. The activity increases with increase in the amount of AgClO4 and reaches maximum at AgClO4/Ni-complex=2. Addition of excess AgClO4 leads to marked decrease in activity with [NiBr(σ-C6F5)(PPh3)2] but a little decrease with [NiCl(σ-C6Cl5)(PPh3)2]. 31P NMR spectra of the active solution showed new resonance peaks due to [Ni(ClO4)(σ-C6X′5)(PPh3)2] and [Ni(ClO4)(σ-C6X′5)(PPh3)] (X′=F,Cl), accompanying formation of AgX (X=Br,Cl) and [Ag(ClO4)(PPh3)]. Thus the role of AgClO4 is to abstract halide anion and/or triphenylphosphine. The amount of Ni(ClO4)(σ-C6X′5)(PPh3)] is in good correlation with the rate of dimerization, which suggests this species to be catalytically active.
The ESR Spectrum of a π Cation Radical Trapped in a Single Crystal of Chloro(tetraphenylporphyrinato)cobalt(III)
Authors: Kohno Masahiro , Ohya-Nishiguchi Hiroaki , Yamamoto Kiyoko , Sakurai Tosio 
Published: July 2006

Abstract
The electron-spin-resonance (ESR) spectra of three paramagnetic species trapped in single crystals of chloro(tetraphenylporphyrinato)cobalt(III) have been observed at 77 K. Using the ESR parameters obtained, one of them has been identified as the [CoIII(tpp)]2+·(Cl−)2 π cation radical, and the other two species, as [CoII(tpp)] which are influenced by axial ligation. From the angular variations in the hfcc due to the 59Co, 14N, and 35Cl in the π cation radical, it has been found that the unpaired electron resides on the a2u porphyrin π orbital and polarizes the Co and Cl atomic orbitals through a spin-polarization mechanism. Finally, the radical formation mechanisms in solution are briefly discussed, based on the results obtained from the single-crystalline measurements.
A Comparison between Ruthenium and Palladium with Regard to the Chemisorption of Carbon Monoxide on Metal Clusters Using Molecular Orbital Calculations
Authors: Kobayashi Masahiro 
Published: July 2006

Abstract
Self-consistent charge extended Hückel calculations for systems consisting of 1–3 CO molecules chemisorbed on 8-atom and 10-atom clusters of Ru and Pd are reported. The binding energies and overlap populations between Pd and C are always smaller than those between Ru and C. It was found that the multiple types of bondings between 2–3 CO and a surface metal atom were less stable for Pd than for Ru.
Electronic Structure and Spectra of Organic Dye Anions of Uranine and Eosin Y
Authors: Hirano Koichi 
Published: July 2006

Abstract
The excited states of the organic dye anions of Uranine and Eosin Y are invesitigated by the semi-empirical SCF-MO-CI calculations. The two-center core integral values of the C–Br bond (−0.20 eV) were determined. Agreement between the calculated and observed spectra was satisfactory. The first intense bands of these dye anions can be assigned to the HOMO→LUMO transition band arising from the local excitation of xanthene ring. The second bands are interpreted as the overlap of the two transition bands for the xanthene ring and for the residual π-systems.