bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Study on Peierls Instability in Quasi-One-Dimensional-System with Interchain-Interactions. Semi-Empirical Self-Consistent-Field Molecular Orbital Approach
Authors: Watanabe Eijiro , Imamura Akira 
Published: July 2006

Abstract
It is widely known that interchain-interactions diminish the Peierls instability in a one-dimensional electronic system. We studied the electronic structure of the (–H–) chains as a model system for the quasi-one-dimensional system. We compare the result of a Hartree–Fock type calculations for a non-interaction chain, a two-chain model with interchain-interactions, two-chain model with interchain-interactions, and a two-dimensional model in which infinite number of chains on the same plane interact with each other. The energy band and the total energy are obtained by the LCAO crystal orbital method using the CNDO/2 approximation. According to the calculated total energy in models with interchain-interactions, for both two-chain and two-dimensional models, the Peierls instability decreases, and disappears for a strong interchain-interaction.
Nonlinear Phenomena in Bromate–Bromide–Cerium(III) System in a Continuous-Flow Stirred Tank Reactor: Reaction Behavior near the Crossing Point in a Cross-Shaped Phase Diagram
Authors: Sasaki Yoshihiro 
Published: July 2006

Abstract
The behavior of a bromate–bromide–cerium(III) system in a continuous-flow stirred tank reactor was simulated near the crossing point in the cross-shaped phase diagram obtained by using linearized stability analysis. The transitions between monostable states and an oscillatory state occur through supercritical and subcritical Hopf bifurcations. The steady states (SSI and SSII) in the neighborhood of the bifurcation points of the subcritical Hopf bifurcations are excitable against perturbations of the concentration of bromide. Some properties of the excitation were also examined. Complicated bifurcations associated with excitability are found in the bistable region near the crossing point. In order to understand bistability and oscillations in this system, the dynamical behavior of a five-variable model was examined by means of a two-variable approximation.
Synthetic Studies on Terpenoid Compounds. XXXIII. A Total Synthesis of (±)-15,16-Epoxy-cis-cleroda-3,13(16),14-triene
Authors: Tokoroyama Takashi , Kanazawa Reizo , Yamamoto Satoru , Kamikawa Tadao , Suenaga Hitoshi , Miyabe Makiko 
Published: July 2006

Abstract
A total synthesis of title cis-clerodane diterpene 9 has been achieved starting from a bicyclic intermediate 4, which was developed previously by us. Firstly the compound 4 was converted by five steps to octalone derivative 6, of which angular methylation, with the protection of 3-methylene group, afforded cis-decalone 7. Appendage of 3-furyl group and deoxygenation at C-20 carbon atom transformed the compound 7 to furanoid ketone 8. Methylenation of 8 followed by the double bond isomerization led to the completion of the synthesis.
New Near Infrared Absorbing Metal Complex Dyes: Synthesis and Metallochromic Properties of Two Isomeric Ligands, 2-(Dimethylamino)naphtho {[1,2-g] and [2, 1-g]} quinoline-7,12-diones
Authors: Yoshida Katsuhira , Koujiri Tetsunao , Sakamoto Eriko , Kubo Yuji 
Published: July 2006

Abstract
The Diels–Alder reaction of 5,8-quinolinedione with p-(dimethylamino)styrenes gave new two kinds of isomeric dyes, 2-(dimethylamino)naphtho[1,2-g]quinoline-7,12-diones and 2-(dimethylamino)naphtho[2,1-g]quinoline-7,12-diones, which showed quite different metallochromic behaviors. Upon addition of metal salts, one of the two isomers showed drastic spectral changes to have an intense absorption band in near infrared region. The color–structure relations were investigated.
Mesomorphic Properties of Bis(4-alkoxycarbonylphenyl)terephthalates
Authors: Matsunaga Yoshio , Miyajima Nobuhiko 
Published: July 2006

Abstract
The mesomorphic behavior of fifteen bis(4-alkoxycarbonylphenyl)terephthalates has been examined in order to study the effects of branching of the ester alkyl groups. The 2-methylation of purely smectogenic butyl, pentyl, and hexyl esters gives rise to the appearance of nematic properties.
Preparation and Molecular Structure of (Methoxo)(octaethylporphinato)iron (III)
Authors: Hatano Keiichiro , Uno Tadayuki 
Published: July 2006

Abstract
The X-ray structure of Fe(OEP)(OMe) is reported: Fe(C36H44N4)(CH3O), F.W.=619.7, monoclinic, P21/c, a=13.412(5) Å, c=18.912(8) Å, β=106.28(3)° and V=3348(4) Å3, Z=4. A methoxide-coordinated iron(III) porphyrinate with π-π dimeric porphyrin interaction in the solid state was revealed. The facile formation of the methoxide is briefly discussed.
Tetramerized Structure of (DMET)2ReO4 and Its Apparent Metallic Behavior in Resistivity
Authors: Saito Kazuya , Ishikawa Yoshimitsu , Ishibashi Masayoshi , Kikuchi Koichi , Kobayashi Keiji , Ikemoto Isao 
Published: July 2006

Abstract
The crystal structure of (DMET)2ReO4 (DMET: 5,6-dihydro-2-(4,5-dimethyl-1,3-diselenol-2-ylidene)dithiolo[4,5-b][1,4]dithiin) was determined, and its resisitivity and thermoelectric power were measured. Crystal data; (C10H10S4Se2)2·ReO4, Mr=1082.88, triclinic, P\bar1, a=6.715(1) Å, b=14.486(2) Å, c=15.867(2) Å, α=101.95(4)°, β=90.05(1)°, γ=78.43(1)°, V=1478.2(3) Å3, Z=2, Dx=2.43 Mg m−3, μ(Mo Kα)=9.62 mm−1, F(000)=1022, T=297 K, R=0.074 for 4391 reflections. The crystal has columnar structure. In the column, a large degree of tetramerization is observed. The resistivity under the normal pressure has metallic temperature dependence above ca. 295 K. The thermoelectric power is essentially constant above 200 K and no anomaly was detected around 295 K. The apparent metallic behavior was attributed to the small activation energy (band-gap) and the temperature dependence of the carrier mobility.
The Application of ESR Spin-Trapping Technique to the Evaluation of SOD-like Activity of Biological Substances
Authors: Mitsuta Keiichi , Mizuta Yukio , Kohno Masahiro , Hiramatsu Midori , Mori Akitane 
Published: July 2006

Abstract
The SOD-like activity of several biological substances was evaluated by an ESR spin-trapping technique. Superoxide radicals (O2\ewdot) were supplied enzymatically from a hypoxanthine–xanthine oxidase reaction to the evaluating system. By using a spin trap 5,5-dimethyl-1-pyrroline N-oxide (DMPO), the generated O2\ewdot was trapped stoichiometrically (1:1) as the spin adduct of O2\ewdot (DMPO–O2−). When biological substances were added to the system, a decrease in the ESR signal intensities of the adducts was observed. This phenomenon could be explained as being an inhibition of adduct formation, and related to the reactivity of added biological substances with O2\ewdot, called an SOD-like activity. By the method of kinetic competition with a 50% inhibitory dose (ID50), the second-order rate constant for the reaction between O2\ewdot and biological substance was determined. These rate constants can be used as a measure of the reactivity.
Lithium Alkylamide Catalyzed Addition Reaction of Alkylamine to Vinyl Monomers. II. Preparation and Q,e-Values of New Styrene Derivative: (S)-N-α-Methylbenzyl-3-vinylphenethylamine
Authors: Hamana Hiroshi , Horiguchi Koichi , Hagiwara Tokio , Narita Tadashi 
Published: July 2006

Abstract
The lithium alkylamide catalyzed addition reaction of α-methylbenzylamine with 1,3-divinylbenzene (m-DVB)was found to produce N-α-methylbenzyl-3-vinylphenethylamine (1:1 adduct) (m-MBVPA), which is a new styrene derivative, and 1,3-bis(N-α-phenethyl-2-aminoethyl)benzene (1:2 adduct). The specific rotation of (S)-N-α-methylbenzyl-3-vinylphenethylamine derived from the optically active (S)-α-methylbenzylamine with m-DVB was found to be [α]D6=−62.2°(c 1.46, CH3OH). The higher reactivity of 1,4-divinylbenzene (p-DVB) compared to m-DVB in this addition reaction system is ascribable to a larger conjugation of p-DVB. The vinyl group of m-MBVPA has been found to show a higher reactivity compared to that in the adduct of MBA with p-DVB. The monomer reactivity ratios and Q,e-values obtained from the radical copolymerization of m-MBVPA (M1) and styrene (M2) were r1=0.48, r2=0.70; Q1=0.62, and e1=0.24.
Oxidation of Alcohols with Electrolytic Manganese Dioxide. Its Application for the Synthesis of Insect Pheromones
Authors: Tsuboi Sadao , Ishii Naomi , Sakai Takashi , Tari Isao , Utaka Masanori 
Published: July 2006

Abstract
Oxidation of alcohols with electrolytic manganese dioxide under mild conditions afforded aldehydes and ketones in good yields. The method was applied for the syntheses of cystophorene [(3E, 5Z)-1,3,5-undecatriene] (15) and a sex pheromone of forest tent cater pillar [(5Z, 7E)-5,7-dodecadien-1-ol (18)].
Reaction of β-Nitroketeneaminal with Olefins Bearing Electron-Withdrawing Group and Aldehydes
Authors: Tokumitsu Takao 
Published: July 2006

Abstract
The reaction of 2-(nitromethylene)imidazolidine (1) with olefins bearing an electron-withdrawing group gave Michael-type addition products and/or 5-nitro-1,7-diazabicyclo[4.3.0]nonane derivatives derived from the Michael-type adduct. The reaction of 1 with α,β-unsaturated aldehydes in the presence of an acid, on the other hand, gave similar diazabicyclic derivatives and 2-[(2-imidazolidinylidene)nitromethylene]-5-nitro-1,7-diazabicyclo[4.3.0]non-5-ene derivatives. The reaction of 1 with saturated and aromatic aldehydes in the presence of hydrochloric acid gave 1,3-bis(2-imidazolidinylidene)-1,3-dinitropropane derivatives. The enhanced enaminic character of 1 is ascribable to the two electron-donating amino groups fixed in a five-membered ring.
Oxidation of Secondary Alcohols over Hydrous Zirconium(IV) Oxide
Authors: Kuno Hideyuki , Takahashi Kyoko , Shibagaki Makoto , Shimazaki Kazuko , Matsushita Hajime 
Published: July 2006

Abstract
The oxidation of secondary alcohols with ketones was carried out by catalysis with hydrous zirconium(IV) oxide. In the batch reaction system, the oxidation proceeded efficiently to give the corresponding ketones, except for some secondary alcohols. On the other hand, all of the secondary alcohols were efficiently converted to the corresponding ketones in the flow oxidation system. The influence of the hydrogen acceptor on the oxidation rate was investigated by the use of several ketones, and the oxidation rate was influenced by the electron density and steric hindrance around the carbonyl group. The dependence on the reaction temperature was also investigated in the flow reaction system.
Effect of Bond-Length Alternation on the Aromaticity of Benzene
Authors: Aihara Jun-ichi 
Published: July 2006

Abstract
Dewar-de Llano PPP-SCF-MO calculations were performed to examine the effect of bond-length alternation on the σ and π frames of benzene. It was confirmed that the equalization of the CC bond lengths in benzene was caused primarily by a high degree of aromaticity. Benzene still is highly aromatic even if it is deformed artificially. Adiabatic and vertical resonance energies were defined for this compound.
General and Highly Efficient Syntheses of m-Fluoro Arenes Using Potassium Fluoride-Exchange Method
Authors: Suzuki Hiroshi , Yazawa Naoto , Yoshida Yasuo , Furusawa Osamu , Kimura Yoshikazu 
Published: July 2006

Abstract
Tetraphenylphosphonium bromide was found to be a suitable catalyst for the reaction of m-nitroaryl derivatives carrying cyano, nitro, chlorocarbonyl, trifluoromethyl, and chlorosulfonyl groups with potassium fluoride in the presence of a stoichiometric amount of phthaloyl dichloride, giving the corresponding m-fluoro aromatic derivatives in good yields. The catalyst was also found to be efficient for the fluorodesulfonylation of m-(fluorosulfonyl)aryl derivatives to afford m-fluoro arenes by the use of a reaction-distillation technique.
Studies of the Acidity and Ionic Conductivity of Silica-Supported Heteropoly Compounds. III. Paramagnetic Species Involved in the Dehydration Reaction on Supported 12-Molybdophosphoric Acid and Its Salts
Authors: Ohtsuka Reiji , Kobayashi Jun-ichi 
Published: July 2006

Abstract
ESR studies on the dehydration reaction of t-butyl alcohol have been carried out while trying to characterize 12-molybdophosphoroc acid (H3PMo12O40) and its salts supported on silica. In H3PMo12O40 supported on silica ESR spectra showed three signals due to molybdenum(V) with three different surroundings: at the interface near the silica support, at the outer surface of the H3PMo12O40 layer and in the bulk of H3PMo12O40. For K3PMo12O40 supported on silica, crystalline K3PMo12O40 is formed on silica, even at low loadings. The ESR spectra of partially potassium-substituted catalysts is also examined.
Synthesis of Dimethylamino Terminated Poly(tetrahydrofuran) and Adhesion Property of Poly(tetrahydrofuran) Ionene Prepared Therefrom
Authors: Kohjiya Shinzo , Ohtsuki Tohru , Yamashita Shinzo , Taniguchi Masaharu , Hashimoto Tamotsu 
Published: July 2006

Abstract
In order to establish the polymerization conditions for the synthesis of bifunctional dimethylamino group terminated poly(oxytetramethylene) (AT-PT), living cationic polymerization of tetrahydrofuran by trifluoromethanesulfonic anhydride was carried out. Especially, factors determining the molecular weight were investigated. The polymerization enabled us to prepare monodispersed AT-PTs having molecular weght between 2000 and 10000. The resultant AT-PTs were bifunctional, i.e., each molecule contains two dimethylamino groups. From AT-PT and dihalide, poly(oxytetramethylene) ionene (PTI) was synthesized in a thin film form. Tensile properties of the PTI films revealed that the films were very tough and elastic. PTI was also found to have high peel strength towards the Bakelite surface. The peel strength increased with the increase of cationic site on PTI main chains, i. e., with the decrease of molecular weight of AT-PT. PTI also had a high permeability of moisture due to the presence of ionic sites. From these results, PTI can be a promising adhesive material for some biomedical application.
Molecular Rotational Potentials in Solid Halogenated Benzenes: C6Cl6, sym-C6Cl3F3, and C6F6
Authors: Nakamura Nobuo , Yoshino Hiroshi 
Published: July 2006

Abstract
In a previous paper which examined the molecular rotation in sym-C6Cl3F3 crystal by the 35Cl NQR an unrealistically long activation parameter, τ0, for the molecular rotation was obtained by assuming the three-fold molecular uniaxial reorientation. In order to examine the reason for such unacceptable result the relaxation time (T1) data were reanalyzed with the help of the computer experiment which calculates the rotational potential function for each molecule in the crystal lattice. The computation was carried out using the 6-exponential type interatomic pair potential functions. It was found that the potential for the plane molecular rotation in the hexagonal unit cell is non-sinusoidal and has, in addition to the most stable orientation, an extra minimum where the molecules can stay for a finite time at moderately high temperatures. The rotational potential thus obtained was used successfully to reanalyze our previous T1 data for this material. 35Cl NQR T1’s were measured for C6Cl6 crystal and analyzed using anisotropic rotational potentials. The analysis predicted possible disordered structure of this material. In the case of C6F6 it was confirmed that the in-plane rotation of two crystallographically inequivalent molecules can be excited with different activation energies from each other, being consistent with the previous fluorine NMR work.
Preparative Method of Fine Powder of Yttrium(III) Oxide by Thermal Decomposition of NH4Y(C2O4)2·H2O Fine Crystals Obtained by New Reaction of Yttrium(III) Hydroxide Slurry with Oxalic Acid Solution
Authors: Minagawa Yukinori , Yajima Fumikazu 
Published: July 2006

Abstract
A fine powder of yttrium (III) oxide used for an additive of new ceramics, such as Si3N4, ZrO2 etc, has been obtained by thermal decomposition (at 750°C for 1.5 h) of NH4Y(C2O4)2·H2O prepared by the reaction of yttrium hydroxide slurry and an oxalic acid solution. This process has facilitated a scale-up for the production of NH4Y(C2O4)2·H2O fine crystals, resulting in low production costs. The formation mechanism of the crystals via Y(OH3) slurry is discussed.
Magnetic Field Effects on the Intramolecular Photoreaction of n-Alkyl Anthraquinone-2-carboxylates
Authors: Tanimoto Yoshifumi , Uehara Megumu , Takashima Masanobu , Itoh Michiya , Hiramatsu Mitsuo , Nakagaki Ryoichi , Watanabe Takeshi , Nagakura Saburo 
Published: July 2006

Abstract
In the photoreaction of n-alkyl anthraquinone-2-carboxylates, AQ-n, magnetic field effects were observed in the decay of biradicals, the formation rate and the yield of cage products and the disappearance yield of AQ-n. The results are interpreted in terms of the radical pair mechanism. Chain length dependence of the disappearance yield indicates that singlet-triplet energy degeneracy of biradicals occurs when n&gt;10.
Crystal and Electronic Structures of (BEDT–TTF)2[MHg(SCN)4](M=K and NH4)
Authors: Mori Hatsumi , Tanaka Shoji , Oshima Masashi , Saito Gunzi , Mori Takehiko , Maruyama Yusei , Inokuchi Hiroo 
Published: July 2006

Abstract
The crystal structures of (BEDT–TTF)2[MHg(SCN)4] (M=K at 298 and 104 K and M=NH4 at 298 K) were determined by X-ray analyses. A donor layer and an anion sheet stack alternately along the b-axis. The packing pattern of the donor is close to α-phase, while an anion sheet constructs a thick two-dimensional polymer plane parallel to (010). The linkage of (Remark: Graphics omitted.) (or NH4) (Remark: Graphics omitted.) in an anion sheet is very unique. The band structure calculation indicates both a closed and an open Fermi surfaces, resembling that of κ-(BEDT–TTF)2[Cu(NCS)2].
Mechanism of Combustion Reactions in Hydrogen–Air Premixed Flames
Authors: Fukutani Seishiro , Kunioshi Nilson , Jinno Hiroshi 
Published: July 2006

Abstract
Simulation was performed by use of a chemical kinetic model built for flat hydrogen–air premixed flames in order to investigate the combustion mechanism taking place in flames through a wide range of equivalence ratio. The following results were obtained: the flame zone of the stoichiometric flame can be considered as having two different regions; the low-temperature region has, furthermore, three parts differing in reaction mechanism; since the reactions cannot proliferate hydrogen atoms by themselves in the low-temperature region, the acceleration of the reactions is necessarily governed by the hydrogen atoms diffused from the flame front; in the high-temperature region, the reactions produce an excess of hydrogen atoms which activate the reactions in this region or diffuse toward the low-temperature region; lean hydrogen flames possess smaller burning velocity than that of rich flames because the reactions in the low-temperature region have less reproducibility of hydrogen atoms.
Photochemically Induced Single Electron Transfer Reactions of Benzils with Allylstannane. Direct Observation of Reactive Intermediates by ESR Method
Authors: Maruyama Kazuhiro , Matano Yoshihiro 
Published: July 2006

Abstract
Although the photochemically induced reaction of benzil with allyltrimethylstannane in benzene afforded α-allylbenzoin as a major product, benzil did not react thermally with the same reagent. An ESR observation disclosed that the benzil anion radical ion-paired upon contact with trimethylstannyl cation (BSnMe3) was generated during irradiation. Its structure was confirmed by the detection of satellite signals arising from tin isotopes. Moreover, a triplet radical pair was also observed during the photolysis of a solid solution containing benzil and allylstannane at 77 K. This reaction proceeded via a single electron transfer from allylstannane to photoexcited benzil, followed by a cleavage of the C–Sn bond of the allyltin cation radical. Ultimately, a radical pair composed of BSnMe3 and the allyl radical was formed and their coupling gave α-allylbenzoin as an isolated product.
Crystal Structure of Potassium 2,2′-(2,5-Cyclohexadiene-1,4-diylidene)bis[propanedinitrile]-1,4,7,10,13,16-hexaoxacyclooctadecane, [K+(“18-Crown-6”)]TCNQ−
Authors: Nogami Takashi , Morinaga Minoru , Mikawa Hiroshi , Nakano Hideyuki , Horioka Miyako , Horiuchi Hiroyuki , Tokonami Masayasu 
Published: July 2006

Abstract
The crystal structure of the title complex was determined by an X-ray diffraction method. The potassium ion is coordinated by six oxygens of a crown ether and two cyano-nitrogens of two TCNQ anion radicals. Both the crown ether dimer and the TCNQ dimer are arranged alternately in the solid.
Acidity and Catalytic Activity of Zirconium and Titanium Sulfates Heat-Treated at High Temperature. Solid Superacid Catalysts
Authors: Arata Kazushi , Hino Makoto , Yamagata Nobutsugu 
Published: July 2006

Abstract
Acidity and catalytic activity of Zr(SO4)2 and Ti(SO4)2 calcined at 500–800°C were studied. The products obtained by calcination at 725°C for Zr(SO4)2 and at 625°C for Ti(SO4)2 showed the highest activity for the cracking of cumene among samples calcined at other temperatures; the former showed an acid strength of −13.16&lt;H0≤−12.70 and the activity for the reaction of pentane.
Structural Phase Transition and Electrical Conductivity of the Perovskite CH3NH3Sn1-xPbxBr3 and CsSnBr3
Authors: Yamada Koji , Kawaguchi Hiroshi , Matsui Takashi , Okuda Tsutomu , Ichiba Sumio 
Published: July 2006

Abstract
A series of solid solutions, CH3NH3Sn1−xPbxBr3 (x=0–1), having cubic perovskite structures was obtained by solid-state reactions. The 119Sn Mössbauer spectra for x&lt;0.4, however, indicated that the tin environment was considerably distorted from a regular octahedron at 110 K. On the other hand, a single Lorentzian spectrum having a large isomer shift was observed for x&gt;0.7, suggesting the presence of a regular SnBr6 octahedra in the perovskite CH3NH3PbBr3 matrix. The high electrical conductivity of the perovskite CsSnBr3 drastically decreased upon the replacement of the cation by CH3NH3 and the central metal by Pb. This behavior suggests that both the infinite linear chain (–Br–Sn(Pb)–Br–) and its bond length have significant importance regarding electrical conductivity.
Regioselective Condensation of Ethynyl Vinyl Ketone or 2-Propynyl Ether Derivatives with Silyl Enol Ethers Catalyzed by Trityl Perchlorate
Authors: Mukaiyama Teruaki , Matsui Shigekazu , Homma Koichi , Kobayashi Sh\={u} 
Published: July 2006

Abstract
In the presence of a catalytic amount of trityl perchlorate, ethynyl vinyl ketone derivatives regioselectively react with silyl enol ethers to afford the corresponding Michael adducts in high yields. 2-Propynyl ether derivatives also react with silyl enol ethers in the presence of a catalytic amount of trityl perchlorate, to give the corresponding adducts in high yields. In the case of the reaction with 2-propynyl ether derivatives, regioselectivities were apparently different between two silylated nucleophiles, silyl enol ethers of ketones and ketene silyl acetals.
Reaction of a Thioaminyl Diradical with 7,7,8,8-Tetracyanoquinodimethane (TCNQ). The Formation of a Cyclophane Compound
Authors: Miura Yozo , Ohana Tsuguyori , Kunishi Teruo 
Published: July 2006

Abstract
The reactions of thioaminyl mono- (MONOR) and diradicals (DIR) with 7,7,8,8-tetracyanoquinodimethane (TCNQ) have been investigated. The reactions of TCNQ with MONOR gave 1:2 adducts of TCNQ and MONOR in 85–88% yields, while the reaction with DIR afforded either a cyclophane compound (77%), or an alternating polymer of TCNQ and DIR (59 wt%), dependent on the structures of DIR.
Synthesis and Spectroscopic Properties of Germanium Naphthalocyanines
Authors: Iwakabe Yasushi , Numata Shunichi , Kinjo Noriyuki , Kakuta Atsushi 
Published: July 2006

Abstract
Two novel naphthalocyanines, naphthalocyaninatobis(triethylsiloxy)germanium GeNc[OSi(C2H5)3]2 and naphthalocyaninatobis(tributylsiloxy)germanium GeNc[OSi(n-C4H9)3]2 were synthesized. These compounds had a strong absorption peak in the near-infrared; the absorption maximum of their evaporated films shifted to the long-wavelength side from the position in solution.