bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electrical and Optical Properties of the 5,6:11,12-Bis(epidithio)naphthacene-Bromine System (TTT–Brn). Formation of Organic Mixed-valence Compounds (TTT)(TTT+)Br− and (TTT+)(TTT2+)(Br−)3
Authors: Matsunaga Yoshio , Takayanagi Kazuhiro 
Published: July 2006

Abstract
The electrical resistivity of the 5,6: 11,12-bis(epidithio)naphthacene-bromine system (TTT–Brn) was examined over the composition range from n=0.3 to 2.0 using polycrystalline compactions. The room-temperature resistivity shows a minimum of about 7 Ω cm near n=0.5, suggesting the formation of a mixed-valence compound, (TTT)(TTT+)Br−. The resistivity increases monotonously with n. No anomaly was found at the composition of (TTT+)Br−. The formation of another mixed-valence compound, the ideal composition of which may be expressed by the formula (TTT+)(TTT2+)(Br−)3, is indicated by an abrupt change of the resistivity from 100 to 4000 Ω cm around n=1.5. This change is accompanied by an increase of the activation energy for semiconduction by a factor of almost two and also by the change of sign in the variation of the Seebeck coefficient with the temperature from positive to negative. A further increase of the resistivity by a factor of ten was observed between n=1.5 and 2.0. The electronic and vibrational spectra support the coexistence of the TTT molecule and the TTT+ ion near n=0.5 and that of the TTT+ and TTP2+ ions near n=1.5.
Nuclear Magnetic Resonance in Hemihydrate Gypsum
Authors: Shimomura Kenji , Nagashima Toshikazu , Sanjoh Akira , Yoshida Makoto , Negita Hisao 
Published: July 2006

Abstract
The proton spin-lattice relaxation times T1 and T1D along the static and dipolar magnetic fields have been measured at 18 MHz for the water molecule in powdered hemihydrate gypsum CaSO4·(1/2)H2O. The minima of T1 and T1D were observed at 103⁄T=4.3(233 K) and 7.0(143 K) respectively. These are ascribed to the 180° flip motion of water molecules, with an activation energy of 15.1 kJ/mol. At higher temperatures, the translational diffusion of water molecules becomes dominant; this is not observed in gypsum CaSO4·2H2O. The activation energy of this motion is estimated to be 32.2 kJ/mol. In hemihydrate gypsum, though the diffusion is supposed to be anisotropic, the jumping distance of the water molecule is tentatively examined by Torrey’s lattice diffusion theory.
Studies on 2-Aziridinecarboxylic Acid. III. Reaction of 1-Acyl-2-aziridinecarboxylic Acid Peptide with Amines
Authors: Nakajima Kiichiro , Tanaka Takumi , Morita Kaoru , Okawa Kenji 
Published: July 2006

Abstract
The reaction of Z–Gly–Azy–Gly–OBzl with amines was studied. With primary amines, the 1-acyl group (Z–Gly) of the aziridine peptide mainly migrated to the reactant amine with cleaving of the amide bond between glycine and aziridine, whereas aniline and diethylamine gave diaminopropionic acid derivatives via the ring opening reaction.
Reaction between Various Copper(II) Complexes and Ascorbic Acid or 3,5-Di-t-butylcatechol
Authors: Oishi Naoyasu , Nishida Yuzo , Ida Kazuhiko , Kida Sigeo 
Published: July 2006

Abstract
The electron transfer reactions between various copper(II) complexes and two-electron donors, such as ascorbic acid and 3,5-di-t-butylcatechol, were investigated. Mononuclear copper(II) complexes with a distorted tetrahedral and a trigonal bipyramidal structure, and some binuclear complexes were readily reduced to copper(I) complexes by the two-electron donors, but not mononuclear planar copper(II) complexes. The catalytic activities of these copper(II) complexes for the oxidation of 3,5-di-t-butylcatechol by O2 were studied in relation to the above reactions.
Electrochemical Reduction of Elemental Sulfur in Acetonitrile
Authors: Fujinaga Taitiro , Kuwamoto Tooru , Okazaki Satoshi , Hojo Masashi 
Published: July 2006

Abstract
Electrochemical reduction of elemental sulfur (S8) has been carried out in acetonitrile using a platinum electrode. The products were identified by means of spectrophotometry and ESR. Sulfur is reduced voltammetrically in two steps:
S_8+2e→S_8^2-, S_8^2-+2e→2S_4^2-
These products turns into more stable species by the succeeding chemical reactions in a bulk solution as follows:
2&S_8^2\oversetK\ightleftarrowsS_6^2-+1/4S_8& &(K=1.6×10^-2)
&S_6^2-\oversetK_d\ightleftarrows2S_3^\ewdot& &(K_d=1.2×10^-3)
The S42− species was enough active to react with S8 into S82−, which was regarded as the cause of a current maximum on the current-time curve in a controlled potential coulometry of S8 at a potential of the second reduction step.
Cyclization Reactions of 2,3-Bis(2-cyanophenyl)propionitriles. III. Substituent Effect on the Carbanion Reactivies of the Propionitriles and Tautomerism of 5-Acetamido-11-cyanoindeno[1,2-c]isoquinolines
Authors: Ando Kazuo , Tokoroyama Takashi , Kubota Takashi 
Published: July 2006

Abstract
The substituent effect in the base-catalyzed cyclization reaction of 2,3-bis(2-cyanophenyl)propionitriles (1) to 5-amino-11-cyano-11H-indeno[1,2-c]isoquinolines has been studied and the result is discussed in terms of the dichotomic carbanion reactivities of 1. Preparation of 1 and the tautomerism of 5-acetamido-11-cyanoindeno[1,2-c]isoquinolines between 5H and 11H structures are described.
Nucleophilic Reaction of Electron-deficient Pyridone Derivatives. II. Ring Transformation of 1-Substituted 3,5-Dinitro-4-pyridones with Sodio β-Keto Esters
Authors: Matsumura Eizo , Ariga Masahiro , Tohda Yasuo 
Published: July 2006

Abstract
The reactions of 1-substituted 3,5-dinitro-4-pyridones [1-substituents: methyl (1a), 2-pyridyl (1b), 6-methyl-2-pyridyl (1c), and 4-pyridyl (1d)] with diethyl sodio-3-oxopentanedioate give 1-substituted 3,5-bis(ethoxycarbonyl)-4-pyridones and sodio-1,3-dinitro-2-propane. On the other hand, the reactions of the 4-pyridones (1b, 1c, and 1d) with ethyl sodioacetoacetate give ethyl 4-hydroxy-3,5-dinitrobenzoate together with aminopyridine homologues, and that of la gives furo [3,2-b] pyridine derivative. On the basis of the concept of soft and hard acids and bases, a stepwise nucleophilic attack of the anion of β-keto esters at the electrophilic center of the 2 and 6-positions or 2 and 3-positions of the 4-pyridones is proposed to interpret the variations of the reaction courses.
Synthesis of Lipophilic Muramyl Dipeptide Derivatives via O-Aminoacyl Intermediates
Authors: Kobayashi Shigeru , Fukuda Tsunehiko , Yukimasa Hidefumi , Imada Isuke , Fujino Masahiko , Azuma Ichiro , Yamamura Yuichi 
Published: July 2006

Abstract
Incorporation of an amino acid into the 6 position of the muramic acid moiety of muramyl dipeptide has been achieved, providing an effective means for the synthesis of various new derivatives. Six new muramyl dipeptide derivatives with an N-acylated amino acid were synthesized using these intermediates and their immunological activity was examined. All the derivatives exhibited adjuvant activity on the induction of delayed-type hypersensitivity to N-acetyl-3-(4-arsonophenylazo)-l-tyrosine.
Aromatic Nucleophilic Substitution. XIII. Confirmation of the Anionic σ Complexes in the Reactions of 2,4-Dinitro- and 2,4,5-Trinitro-1-(1-piperidyl)naphthalenes with Piperidine in Dimethyl Sulfoxide
Authors: Sekiguchi Shizen , Hikage Reiko , Obana Kenmi , Matsui Kohji , Ando Yumiko , Tomoto Noboru 
Published: July 2006

Abstract
In the reactions of 2,4-dinitro- and 2,4,5-trinitro-1-(1-piperidyl)naphthalenes with piperidine in dimethyl sulfoxide, the 1,1-disubstituted anionic σ complex was confirmed to exist with visible absorption and NMR spectra. Especially in the latter case the 1,3-disubstituted anionic σ complex was formed, the cause of formation of which was ascribed to the deactivating effect of 1-piperidyl group on C1-position of a napthtalene ring and the steric effect of 1-piperidyl group on the nucleophilic attack of piperidine on C1-position. These factors make the 1,1-disubstituted anionic a complex unstable.
Synthetic Identification of Bitter Heptapeptide in Tryptic Hydrolysate of Casein
Authors: Hashimoto Akio , Aoyagi Haruhiko , Izumiya Nobuo 
Published: July 2006

Abstract
A heptapeptide, H–Cly–Pro–Phe–Pro–Ile–Ile–Val–OH (1), was synthesized and found to be indistinguishable from the natural peptide (2), isolated from a tryptic hydrolysate of Hammersten casein by means of chromatography, amino acid analyses, and mass spectrometric measurements. Both peptides (1 and 2) have a strong bitter taste.
Highly Strained Ring Systems. Hydrolysis of endo-Tetracyclo[5.2.0.02,4.03,5]non-8-en-6-yl p-Nitrobenzoate. Importance of Anchimeric Assistance by Bicyclobutane Ring. II
Authors: Isobe Masayoshi , Yano Kazuyuki 
Published: July 2006

Abstract
Solvolytic reactivity of endo-tetracyclo[5.2.0.02,4.03,5]non-8-en-6-yl p-nitrobenzoate(1-OPNB), endo-bicyclo-[4.1.0]hept-2-yl p-nitrobenzoate(2-OPNB), and endo-bicyclo[4.2.0]oct-7-en-2-yl p-nitrobenzoate(4-OPNB) was investigated in 50% aqueous acetone. 1-OPNB was less reactive than 2-OPNB that has no cyclobutene ring and more reactive than 4-OPNB that has no bicyclobutane ring. Product study in solvolysis of 1-OPNB was undertaken leading to the rearranged tricyclic alcohol as a major product. The importance of conformational factor for anchimeric assistance by bicyclobutane ring is discussed.
Oxidative Cleavage of Tin–Tin Bonds in Hexaalkyldistannane with Several 1,4-Benzoquinones, Detection of the Semiquinone Radicals and 4-(Trialkylstannoxy)phenoxyl Radicals by ESR spectroscopy.
Authors: Kozima Sinpei , Fujita Hideo , Hitomi Torazô , Kobayashi Kazuhiko , Kobayashi Kazuko , Kawanisi Mituyoshi 
Published: July 2006

Abstract
The mechanism of the oxidative cleavage of tin–tin bonds in hexamethyldistannane (Me3SnSnMe3) and hexabutyldistannane (Bu3SnSnBu3) with several 1,4-benzoquinones was investigated. Chlorine-substituted 1,4-benzoquinones exerted higher reactivity, implying that the electron-acceptability of quinone is a factor governing the reaction. Stoichiometric treatments of chloranil with the distannanes ruled out the alleged isolation of the free radical, 4-(trimethylstannoxy)phenoxyl radical, reported by Gornwell et al. The final products were not the free radical entity but normal compounds, 1,4-bis(trimethylstannoxy)benzenes. Measurements of ESR spectra revealed the formation of the semiquinone radical anions and the subsequent formation of 4-(tributylstannoxy)phenoxyl radicals as reactive intermediates in the reaction pathway.
New Routes to the Pyrrolo[2,1,a]isoquinoline System
Authors: Iwao Masatomo , Kuraishi Tsukasa 
Published: July 2006

Abstract
Some derivatives of the title ring system were prepared from methyl α-(1-isoquinolyl)-β-aminocrotonate and ethyl α-(1-isoquinolyl)-β-amino-β-ethoxyacrylate in moderate to good yields via their quaternary salts.
Restricted Rotation Involving the Tetrahedral Carbon. XXXIII. Restricted Rotation about a Csp3–Csp2 Bond in 10,10-Disubstituted 9-(2,6-Xylyl)-9,10-dihydroanthracene Derivatives
Authors: Nakamura Mikio , Oki Michinori 
Published: July 2006

Abstract
A series of 10,10-disubstituted 9-(2,6-xylyl)-9,10-dihydroanthracene derivatives have been prepared and their conformations and barriers to internal rotation about the Cxylyl–C9 bond have been examined. These compounds exist predominantly as a pseudo-equatorial form in the ground state for rotation. A large effect is inserted by the substituents in 10 position on barriers to rotation and is interpreted in terms of a rotation-inversion mechanism rather than a simple rotation mechanism for the methyl-exchange process which is observed by 1H NMR spectra. The highest barrier to rotation has been found in the compound having two peri-chloro groups and a hydroxyl group in 9-position. The high barrier is ascribed to destabilization of the transition state, where 9-aryl group takes axial conformation, due to the three electronegative groups which are forced to be arranged parallelly in quite a near region. The change of 9-OH to 9-H thus decreases the barrier to rotation when peri-chlorines are present, while the increase in barrier is observed as in the case of 9-arylfluorenes and 9-arylxanthenes when they are absent.
Differential Refractometric Studies on Some Strong and Weak Molecular Complexes
Authors: Sahai Ram , Singh Vinod , Verma Rekha 
Published: July 2006

Abstract
A more adequate model has been developed to determine the equilibrium constant (K1) and stoichiometry of molecular complexes. This model involves the assumption:
&Δφ_a/C_D°={K_1C_A°/α(1+K_1C_A°)}-{K_1Δφ_a/(1+K_1C_A°)^2}
&Δφ_d/C_D°={K_1C_A°/α(1+K_1C_A°))}-{K_1Δφ_d/(1+K_1C_A°)^2}
where Δφa difference in the refraction per cm3 of solution and acceptor; Δφd is the difference in the refraction per cm3 of solution and donor; α is the extent of electronic polarization. CA° and CD° are the initial concentrations of acceptor and donor respectively. This model has been verified on some strong and weak complexes and was found better than that of earlier methods. Δφa, Δφd, and ΔΩCDA (refraction per cm3 due to chargetransfer complex) have also been used to Yoshida and \barOsawa’s method. The K1 obtained from the plot of Δφa or Δφd versus molar ratio of solutes were found more reliable for weak complexes than K1 calculated from Yoshida and \barOsawa’s plot. From these plots the percentage of contribution of donor or acceptor in total 30% solute aggregation as proposed by Yoshida and \barOsawa has been calculated. It is also noted that Yoshida and \barOsawa’s method may give the reliable value for strong complexes but for weak complexes only differential refractometric method can provide the best values.
Synthesis and Studies of Some Novel Analogues of Phthalein Dyes
Authors: Chamoli R P , Rai S J , Gupta P C 
Published: July 2006

Abstract
Some novel analogues of phthalein dyes have been synthesized by condensing a γ-keto acid, 2-(2-thenoyl) benzoic acid with various phenols. The dyes so obtained are unsymmetrically substituted phthalides where the central carbon atom is attached with two different rings and these dyes have been named as phthal-as-eins;-‘as’ representing unsymmetry, and-‘ein’ class of the compound (phthal-ein). The structures of these products have been established on the basis of their elemental analysis and chemical reactions. Absorption maxima of these new dyes have been determined and compared with those of true phthaleins.
Ortho Effects in Organic Molecules on Electron Impact. VIII. Intramolecular Aromatic Substitution in (Arylmethylene)barbituric Acids
Authors: Ramana Devalla Venkata , Kasi Viswanadham Somayajula 
Published: July 2006

Abstract
Mass spectral decomposition process involving intramolecular aromatic substitution with the ejection of either the hydrogen or the substituent in the ortho position from the M+· ion is noticed in the eleven 5-(arylmethylene) barbituric acids studied. It has been generally noticed that for such a cyclization to occur, the presence of an α,β-unsaturated carbonyl function, in conjugation with the ring, is essential in aromatic systems.
Bulk Copolymerization of Acrylonitrile with α-Chloroacrylonitrile
Authors: Okamoto Masao , Ishizuka Osamu 
Published: July 2006

Abstract
Copolymerization of acrylonitrile (M1) with α-chloroacrylonitrile (M2) was carried out at 60 °C using 4.3×10−2 mol% of α,α′-azobisisobutyronitrile. The four copolymers obtained were analyzed, their mole fractions of α-chloroacrylonitrile units being 0.196, 0.377, 0.532, and 0.722, and the monomer reactivity ratios r1 and r2 were found to be 0.31 and 3.25, respectively.
The Solvent Effects of Water–Dimethyl Sulfoxide Mixtures on the Keto-Enol Tautomerization Rate of Di-n-alkyl β-Diketones
Authors: Watarai Hitoshi 
Published: July 2006

Abstract
The kinetic solvent effects of water–dimethyl sulfoxide (DMSO) mixtures on the ketonization and the enolization rate constants of eight di-n-alkyl β-diketones were analyzed in terms of the group-transfer free energy from water to the mixed solvents. The transfer free energy of the transition state, as calculated from the rate constant and the partition coefficient of the keto or enol form, is found to be divided into three contributions: the two group-transfer free energies of the “transition state skeleton” and the methylene group, and the transfer free energy change due to the inductive effect of the n-alkyl group.
Kinetic Studies of the Electron Transfer Reaction in Iron(II) and Iron(III) Systems. X. The Electron Transfer Reaction between Iron(II) and Iron(III) in the Presence of Pyridine in Aqueous Solution
Authors: Wada Goro , Kawauchi Aiko 
Published: July 2006

Abstract
When pyridine is added to the reaction system of the electron transfer between Fe(II) and Fe(III) in aqueous solution at constant [HClO4]o, the apparent rate constant k grows rapidly with [Py]o at [Py]o&lt;C[HClO4]o, while k suddenly diminishes to a small and constant value at [Py]o&gt;[HClO4]o. The predominant paths of the reaction will be discussed.
A.c, Polarographic Determination of Cyanide Ion after Conversion to Mercury(II) Cyanide by Use of Hg-form Resin
Authors: Hanagata Goro , Ohzeki Kunio , Kambara Tomihito 
Published: July 2006

Abstract
Cyanide ion was converted to mercury(II) cyanide by shaking with Hg(II)-form resin and determined by a.c. polarography at pH 9.0. The recovery was 80.5%. A linear calibration curve was obtained in the cyanide concentrations ranging from 10−4 to 10−3 M (1 M=1 mol dm−3).
Evidence for Electron-transfer Process in Abnormal Grignard Reactions. Enolization and α-Diketone Formation
Authors: Okubo Masao , Morigami Yoshiaki , Suenaga Reiko 
Published: July 2006

Abstract
The effect of 2,6-dimethyl groups on enolization vs. addition in the reaction of PhMgBr with PhCH2COPh, and also the formation of α-diketone from 2,4,6-Me3C6H2COCl by the treatment with MeMgX and i-PrMgX in the presence of CoCl2, were studied. The results were discussed on the basis of electron-transfer mechanism.
A New Synthesis of Allethrolone
Authors: Ono Noboru , Tanabe Yo , Tanikaga Rikuhei , Kaji Aritsune , Matsuo Takashi 
Published: July 2006

Abstract
A new synthesis of 2-allyl-4-hydroxy-3-methyl-2-cyclopenten-1-one, so called allethrolone is described, in which the Michael addition of 3-phenylthio-5-hexen-2-one to 1-nitro-1-propene followed by conversion of the nitromethyl group in the adduct to an aldehyde function is involved as the key step.
ESR Studies of Abnormal Methyl Radicals on Various Solid Surfaces
Authors: Oduwole Duro A , Wiseall Barrie 
Published: July 2006

Abstract
Direct spectroscopic evidence is presented that strongly caged methyl iodide (or methane) molecules in porous surfaces are the precursors of abnormal methyl radicals. The implication of this result as concerns the nature of radical surface interaction is discussed in terms of a matrix effect.
The Hydrothermal Activation of Silica–Alumina for Butene Isomerization. A Device to Prepare a Standard Sample
Authors: Furuyama Shozo , Murashita Osamu , Yukumoto Yuko , Morimoto Tetsuo 
Published: July 2006

Abstract
Three kinds of silica–alumina catalysts were prepared by hydrothermal treatment (heating a sample in hot water) over the range of 25–250 °C for various periods. It was found that the hydrothermal treatment significantly increased its catalytic activity for butene isomerization. The dependencies of various surface properties (the production ratio of 2-butene isomers, the surface acidity, the surface area, the pore-size distribution, and the shape and size of the catalyst particle) on the hydrothermal conditions and the kind of starting catalyst sample were systematically investigated, too. It was concluded that the increase in the catalytic activity might be due to the progress of the Si/Al isomorphic substitution in the tetrahedral surface silica network. Hot water might serve as a solvent for the cations and facilitate their movements. Since the hydrothermal treatment can erase the effects of the blending method on the catalytic activity and other surface properties almost completely, this treatment can be used to prepare a standard sample.
Studies of the Magnetic Circular Dichroism and Tautomerism of Pyridinols (Pyridinones) and Pyrimidinols (Pyrimidinones)
Authors: Kaito Akira , Hatano Masahiro 
Published: July 2006

Abstract
The magnetic circular dichroism(MCD) spectra of pyridinols (pyridinones) and pyrimidinols (pyrimidinones) were measured in the wavenumber region of 27000–50000 cm−1. The transition energies, the oscillator strengths, and the Faraday B terms were calculated within the framework of the INDO/S-CI approximation. The calculated results for the π*←π transitions were in good agreement with the experimental results. The lactim-lactam tautomerism of 3-pyridinol(3(1H)-pyridinone) and 2-pyrimidinol (2-pyrimidinone) was discussed.
Liquid Crystal Formation in Binary Systems. II. Induction of Nematic and Smectic Phases by Electron Donor-Acceptor Interaction between the p-Dimethylamino and p-Nitro Derivatives of N-Benzylideneaniline
Authors: Araya Kotaro , Matsunaga Yoshio 
Published: July 2006

Abstract
The formation of solid molecular complexes and the induction of nematic and smectic phases have been demonstrated with a number of binary mixtures of potentially-mesomorphic electron donors and acceptors of the type N-(p-X-benzylidene)-p-Y-aniline. One of the components contains a dimethylamino group as X or Y, and the other a nitro group as X or Y. The remaining substituents are methoxyl, ethoxyl, or propoxyl groups. The maximum temperature of the nematic phase induced in these electron donor-acceptor systems is higher by 23 to 45 °C than the straight line joining the latent transition temperatures of the two components. The tendency to form a solid complex and that to induce a nematic phase are both shown to a large extent by the propoxy derivatives, to a lesser extent by the methoxy derivatives, and least by the ethoxy derivatives. All the solid molecular complexes are reddish brown and exhibit an additional electronic absorption band located at about 500 nm. The mesophases are similarly colored. The enhanced thermal stability of the nematic and smectic phases in these binary mixtures is ascribed to the complex formation by an electron donor-acceptor interaction.
Charge Transfer and Proton Transfer in the Formation of Molecular Complexes. XII. o-Aminobenzoic Acid–Picric Acid and Related Complexes
Authors: Matsunaga Yoshio , Usui Reiko 
Published: July 2006

Abstract
The combination of o-aminobenzoic acid and picric acid was found to yield four kinds of adducts. These were a stable yellow (1:1) salt, formed by the proton transfer from the picric acid to the o-aminobenzoic acid molecule, two red (1:1) molecular complexes of markedly different stability, and a red (2:1) complex consisting of the o-aminobenzoic acid molecule, its protonated ion, and the picrate ion. The enthalpy change and the activation energy for the isomerization from the salt to the charge-transfer complex by a solid-solid transformation were shown to decrease during storage. The 1,3,5-trinitrobenzene complexes with o-(methylamino)benzoic acid, o-, m-, and p-(dimethylamino)benzoic acids, and their sodium and potassium salts were prepared. Their electronic spectra were measured, along with those of the complexes with o- and p-aminobenzoic acids and their salts presented in the work of Sudborough and Beard. The displacement of the charge-transfer absorption maxima to the lower wavenumber side by the salt formation is 2×103 cm−1 on the average and seems to be consistent with our proposition that the picrate ion acts as an electron acceptor in aromatic amine-picric acid (2:1) complexes.