bluuebunny/crossref_metadata_2025_split huggingface dataset:
Isotopic Fractionation in a Thermal Ion Source
Authors: Kanno Hitoshi 
Published: July 2006

Abstract
Isotopic fractionation behavior in a thermal ion source was theroretically studied. An equation relating to the observed isotope ratio with the evaporated fraction of the sample was derived under conditions where two kinds of chemical species, atomic (atomic ions and neutral atoms) and molecular (molecular ions and molecules) species, simultaneously evaporate from the filament. It was demonstrated that integrations of all ion currents for two isotopes do not necessarily give a true ratio of the two isotopes in the sample when two evaporating chemical species are ionized at different rates. Isotopic fractionation curves for halides and elements of lithium, potassium, and rubidium are presented.
Restricted Rotation Involving the Tetrahedral Carbon. II. 2-Substituted 4,6,8-Trimethylazulenes
Authors: Oki Michinori , Nakamura Nobuo 
Published: July 2006

Abstract
1-(1-Hydroxyethyl)-4,6,8-trimethylazulene (3) was prepared by the lithium aluminum hydride reduction of 1-acetyl-4,6,8-trimethylazulene, and by the reaction of methylmagnesium iodide with 1-formyl-4,6,8-trimethylazulene. 3 showed various melting points according to its crystallization conditions and the reaction solvent. Their IR spectra both in solid states and in solutions, the NMR spectra at various temperatures, and the results of X-ray diffraction studies led to a conclusion that this phenomenon is attributable to polymorphism. From the temperature dependence of the NMR spectra of the t-butyl protons of 1-t-butyl-4,6,8-trimethylazulene, the internal rotation around the CBu–Cazulene was concluded to be slow only at the lower temperature.
The Trialkylborane-initiated Graft Copolymerization of Methyl Methacrylate onto Hemoglobin
Authors: Kojima Koichi , Iwabuchi Susumu , Kojima Kuniharu , Tarumi Niro 
Published: July 2006

Abstract
The graft copolymerization of methyl methacrylate by trialkylborane onto hemoglobin has been studied at 37°C. In aqueous media, graft copolymers were obtained in the form of a light brown powder or granules, while no grafting occurred in organic solvents, such as cyclohexanone, n-hexane, tetrahydrofuran, and toluene. The presence of water seems to be essential to the grafting. The hydrogen peroxide-decomposing property of hemoglobin was well preserved in the graft copolymers so obtained. The mechanism of the initiation is discussed.
The Effect of Water on the Reduction Potentials of Some Aromatic Compounds in the DMF-Water System
Authors: Hayano Shigeo , Fujihira Masamichi 
Published: July 2006

Abstract
From the viewpoint of the interaction between the oxidized or the reduced form of a depolarizer and solvents, the solvent effect on the half-wave potentials was studied. Another factor affecting the E1⁄2, i.e., pH or ion-pair formation, was also examined. The correction for the liquid junction potential was carried out by the use of the ferrocene standard. The reduction products, radical anions or dianions, were found to be stabilized by the hydrogen-bonding with water where the hydrogen-bond interaction of the dianion was stronger than that of the monoanion. Aromatic hydrocarbon radical anions, whose charges are dispersed over the molecule, were less susceptible to this solvent transfer than were the anthraquinone radical anion and the dianion, whose charges are strongly localized.
The Electronic Structures of trans and cis Isomers of Some Halogenoethylenes
Authors: Kato Hiroshi , Hirao Kimihiko , Konishi Hideyuki , Yonezawa Teijiro 
Published: July 2006

Abstract
By using the closed-shell SCF MO method with the zero-differential overlap approximation for all valence electron systems previously presented by us, the electronic structures of trans- and cis- substituted ethylenes (treated substituent=CH3, Cl, Br, and I) are studied. The calculated values of the π and valence electron charges, and the total energies of these isomers are presented. The natures of the higher occupied MO’s, especially the lonepair MO’s, of chlorinated ethylenes are discussed in connection with the photoelectron observation. The calculated lowest π–π* singlet transition energies accord well with the observed values. As to the rotational energy changes, the calculated results show that, at the perpendicular configurations, the triplet states for all the treated compounds are lowest, while the intermediate states for the cis-trans isomerizations of these compounds may be common to both the isomers.
Magnetic Properties of Some Iminoxyl Polyradicals. II. TEMPOP Triradical and TEMPOS Tetraradical
Authors: Nakajima Akira , Ohya-Nishiguchi Hiroaki , Deguchi Yasuo 
Published: July 2006

Abstract
The EPR spectra of the TEMPOP triradical and the TEMPOS tetraradical in solution showed seven and nine absorption lines respectively, which were interpreted as the hyperfine interaction between unpaired electron and 14N nuclei in the case of |Jin|&gt;&gt;A. The paramagnetic susceptibilities of TEMPOP and TEMPOS were measured. In the case of TEMPOP, no typical short-range ordering effect was found, but the 1⁄χM−T curve deviated from the Curie-Weiss law at very low temperatures. In the case of TEMPOS, the 1⁄χM−T curve was divided into four regions. In the first and third regions, the 1⁄χM−T curves both obey the Curie-Weiss law. The second region is the intermediate region between the first and third regions. In the last region, 1⁄χM−T shows a slight deviation from the Curie-Weiss law of the third region. In order to explain this behavior, some spin-cluster models with three and four spins were applied.
The Bromination of 4-Acetyltropolone
Authors: Takase Kahei , Sasaki Kazuya , Shimizu Kohei , Nozoe Tetsuo 
Published: July 2006

Abstract
The bromination of 4-acetyltropolone was examined, and two kinds of monobromo compounds, 4-acetyl-3-bromo- and 4-acetyl-7-bromotropolones, two kinds of dibromo compounds, 4-acetyl-3,7-dibromo- and 7-bromo-4-(ω-bromoacetyl)tropolones, a tribromo compound, 4-acetyl-3,5,7-tribromotropolone, and a tetrabromo compound, 3,5,7-tribromo-4-(ω-bromoacetyl)tropolone, were obtained. The third isomer of the monobromo compounds, 4-acetyl-5-bromotropolone, was synthesized from 4-acetyltropolone through 4-acetyl-5-aminotropolone. Moreover, an isomeric dibromo compound, 4-acetyl-5,7-dibromotropolone, was obtained by the debromination of the tribromo compound.
A New Route to Polycondensed Aromatics: Photolytic Formation of Triphenylene and Dibenzo[fg,op]naphthacene Ring Systems
Authors: Sato Takeo , Shimada Shigeru , Hata Kazuo 
Published: July 2006

Abstract
Application of photo-aryl coupling reactions for the syntheses of triphenylene and dibenzo[fg,op]naphthacene was explored. Three types of reactions were developed: Photocyclodehydrogenation of polyphenyl compounds, photolytic reactions of iodoarenes, and photocyclodehydrohalogenation of halogenopolyaryls. The effects of solvent, oxidant, and wavelength on the photocyclization of o-terphenyl and 2,2′-diphenylbiphenyl to the triphenylene and naphthacene, respectively, were examined. The conversion was best achieved by the reaction carried out in an aromatic solvent in the presence of an equimolar amount of iodine using a quartz or a Vycor vessel. Versatility of the processes was shown by the formation of naphthacene starting from either 2,2′-diphenyl-biphenyl (57% yield), 2,2′-bis(2-chlorophenyl)biphenyl (67%), 1,2,3-triphenylbenzene (21%), or 2,6-diiodo-biphenyl.
Nuclear Quadrupole Resonance Study of Charge Transfer Complexes: Chloranil Complexes
Authors: Chihara Hideaki , Nakamura Nobuo 
Published: July 2006

Abstract
35Cl nuclear quadrupole resonance frequencies were measured in electron donor-acceptor complexes between chloranil (tetrachloro-p-benzoquinone) and such donors as aromatic hydrocarbons, polyaromatics and amines. Some correlations between the resonance frequencies and infrared spectra were found and discussed in a qualitative way in terms of the π-electron transfer between donors and the chloranil molecule as acceptor. A Zeeman effect experiment was carried out on a single crystal of the 1:2 chloranil-8-hydroxyquinoline complex. The direction of one of the two non-equivalent C-Cl bonds obtained slightly differs from that determined by an X-ray diffraction study. Possible effects of the charge transfer on the resonance frequency and the asymmetry parameter are discussed according to the Mulliken theory of ’weak’ charge-transfer complex. No simple relations could be found between the experimental resonance frequencies and the ionization potential of the donor. This suggests that crystal field effects are rather large in comparison with the effect of charge transfer interaction.
Studies of Benzoylsulfene. IV. The Cycloaddition Reactions of Benzoylsulfene with Cinnamylideneamines
Authors: Tsuge Otohiko , Iwanami Sumio 
Published: July 2006

Abstract
The reaction of benzoylmethanesulfonyl chloride with cinnamylideneamines in the presence of triethylamine has been investigated; the products were identified, by spectral studies as well as by chemical transformations, as the corresponding Diels-Alder adducts of benzoylsulfene as a dienophile to the α,β-unsaturated anils, 2-substituted 5H, 6H-6-benzoyl-5-phenyl-1,2-thiazine 1,1-dioxides, in which the phenyl and benzoyl groups are quasi-equatorial and quasi-axial respectively. The cycloadducts underwent inversion, on treatment with sodium methoxide in methanol or with silica gel in chloroform, to the corresponding epimers, in which both the phenyl and benzoyl groups are quasi-equatorial.
Studies of the Liquid-Liquid Partition Systems. VIII. Stabilities and Extractabilities of Copper(II) and Zinc(II) Complexes with Acetylacetone, Trifluoroacetylacetone, and Hexafluoroacetylacetone in Aqueous Sodium Perchlorate Solution-Carbon Tetrachloride Systems
Authors: Sekine Tatsuya , Ihara Naohiko 
Published: July 2006

Abstract
The distribution of copper(II) and zinc(II) chelates with three β-diketones, acetylacetone (AA), trifluoroacetylacetone (TFA), and hexafluoroacetylacetone (HFA) between carbon tetrachloride and aqueous sodium perchlorate solutions at 0.1m, 1m, and 3m has been determined at 25°C as a function of the concentration of the dissociated chelate anions. The stability constants for the metal chelates in the aqueous phase and the two phasedistribution constants for the uncharged complexes have been determined by a graphic analysis of the distribution data. The distribution was also measured when the carbon tetrachloride phase was added with tributylphosphate (TBP) or trioctylphosphine oxide (TOPO) and the adduct-formation constants of the uncharged chelate with these ligands have been determined by a graphic analysis of the increase in the distribution ratio as a function of the ligand concentration. The results are as follows: (i) Copper(II) forms first and second complexes with these chelating ligands in the aqueous phase, whereas zinc (II) forms the third complex (except with HFA) besides the first and the second ones; the complexes are more stable in the ligand order of AA&gt;TFA&gt;HFA. (ii) The stability constants of the copper(II) complexes are much higher than those of the corresponding zinc(II) complexes. (iii) The distribution constant of the uncharged copper(II) complex is higher than that of the corresponding zinc(II) complex. (iv) No remarkable relation has been found among the distribution constants of the chelating acid and those of the uncharged metal chelates. (v) The adducts of the metal chelates are more stable in the ligand order of HFA&gt;TFA&gt;AA. The zinc(II) complex forms more stable adducts than does the corresponding copper(II) complex, and TOPO forms more stable adducts than does TBP. (vi) Changes in the concentration of the background salt alter the stability constants of the metal chelates and the distribution constants of the uncharged chelate (salting-out); the effects are, however, very complicated. On the basis of these results, the distribution constants of the uncharged chelates were discussed from the standpoint of the interactions of the central metal ions in the complexes with the water molecules, and a qualitative relationship between these interactions and the stabilities of the adduct chelate complexes was pointed out.
The Stereochemistry of 5-Substituted 2-Oxo-3-aryl-1,2,3-oxathiazolidines
Authors: Nishiyama Tomihiro , Yamada Fukiko 
Published: July 2006

Abstract
New six 2-oxo-3-aryl-5-methyl-1,2,3-oxathiazolidines and six 2-oxo-3-aryl-5-chloromethyl-1,2,3-oxathiazolidines have been prepared in good yields by the reactions of N-sulfinylanilines with propylene oxide and epichlorohydrin respectively in the presence of catalysts. The compounds obtained exist in isomeric cis and trans forms at the S=O bond. The configurations of their stereoisomers were discussed by means of NMR.
Radiotracer Studies on Adsorption of Surface Active Substance at Aqueous Surface. IV. Direct Measurement of Adsorption of Tritiated Nonionic Surfactant
Authors: Tajima Kazuo , Iwahashi Makio , Sasaki Tsunetaka 
Published: July 2006

Abstract
The radio- and surface-chemically pure nonionic surfactant, C10H21(CHT)2O(C2H4O)6H, was synthesized, and surface tension and adsorbed amount of its aqueous solution were measured directly at the air-solution interface at 30°C. Surface tension was measured by the drop-volume and Wilhelmy plate methods, while adsorbed amount was measured by the radiotracer method. The adsorption isotherm showed saturation values of 2.73×10−10 mol/cm2 above the concentration of about 1/5 of the critical micelle concentration. The observed amount of adsorption was in good agreement with the values calculated from surface tension data measured by the Wilhelmy plate method by applying the Gibbs adsorption isotherm for a single solute system. The time dependence of surface tension of surfactant solution was further discussed, and the inherent time dependence was shown for pure surfactant solution.
Syntheses of Acylurea Derivatives as Model Compounds for a Highly Specific Organic Reaction
Authors: Endo Tadashi , Noguchi Shigeru , Mukaiyama Teruaki 
Published: July 2006

Abstract
Some types of acylurea derivatives were prepared as model compounds for a highly specific organic reaction by molecular association. When ethyl chloroacetate was treated successively with o-aminobenzenethiol (4) and chloroacetyl isocyanate (1) under mild conditions, triacylurea derivative (9) was obtained in total 84% yield. It was found that the use of “amino acid amide and oxalyl chloride” method led to the formation of diacylurea derivative (11) in high yield.
Studies on Stable Free Radicals. VI. Synthesis of Substituted 4-Imidazolidinone-1-oxyls
Authors: Toda Toshimasa , Morimura Syoji , Mori Eiko , Horiuchi Hideo , Murayama Keisuke 
Published: July 2006

Abstract
It was found that the reaction of α-amino nitriles with carbonyl compounds gave the substituted 4-oxoimidazolidines in the presence of basic catalyst. These imidazolidinones were oxidized by hydrogen peroxide: although the imidazolidinones containing an α-hydrogen at the 2- or 5-position gave no radical products, 2,2,5,5-tetrasubstituted imidazolidinones afforded new stable nitroxide radicals. By this method, stable biradicals were also prepared; but, no corresponding stable nitroxide radical was isolated by oxidation of substituted imidazolidine-4-thiones.
Modified INDO Calculations of the Electronic Structure of Organic Molecules. I. Electronic Excitation Energies of Some Carbonyl Compounds and Conjugated Dienes
Authors: Yamaguchi Kizashi , Fueno Takayuki 
Published: July 2006

Abstract
The semi-empirical valence-shell SCF MO theory (the INDO method) by Pople et al. has been modified for the purpose of calculating the electronic excitation energies of organic compounds. All the necessary one-center parameters have been evaluated from the valence-state ionization data of Hinze and Jaffé, combined with the Slater-Condon atomic parameters. The INDO method thus modified has been applied to carbonyl compounds and conjugated dienes. The calculated excitation energies have been found to be satisfactory in many respects.
Thermal and Photolytic Decompositions of Azobis(2-phenoxy)-2-propane
Authors: Ohno Atsuyoshi , Kito Noboru , Ohnishi Yutaka 
Published: July 2006

Abstract
Thermal and photolytic decompositions of azobis(2-phenoxy)-2-propane have been studied. More than half of the 2-phenoxyprop-2-yl radicals thus produced thermally cause the phenyl group to migrate from oxygen to the carbon, followed by elimination of the methyl group. Most of the remaining radicals abstract hydrogen from the solvent. When phenyl ether is employed as a solvent, homolytic aromatic substitution takes place yielding isopropylbenzene derivatives. It is shown by mechanistic consideration, although not completely decisively, that this is a new type of reaction in the sense that a part of the leaving group constitutes a part of the entering group.
Coexistence States of Iron in Synthesized Iron-bearing Allophane (Al2O3-SiO2-Fe2O3-H2O System)
Authors: Ossaka Joyo , Iwai Shin-ichi , Kasai Mitsuhiro , Shirai Toshiaki , Hamada Shuichi 
Published: July 2006

Abstract
A sharp exothermic peak at 980°C, which is found characteristic of allophane in its differential thermal analysis, shifted to the lower-temperature side and broadened as the iron content in the iron-coprecipitated samples increased. In the case of the iron-mixed samples, however, this exothermic peak did not shift, and a new broad exothermic peak, which was ascribed to hydrated ferric oxide, appeared. The crystallization processes in the heat-treated samples were found to depend on the coexistence state and the quantity of the iron. The dimensions of a unit cell of the mullite, crystallized at 1200°C from the iron-coprecipitated samples, varied with the iron content. The iron-mixed samples, however, showed little change in their cell dimensions. It is concluded that there are two states of the coexistence of iron in the allophanes. In one of them, iron ions form solid solutions of the allophane, i.e., as an iron-allophane. In the other, iron is in the mixture as the hydrated ferric oxide. The maximum amount of iron in the solid solution was estimated to be 5 wt% in the iron-allophane.
Mechanism of The Ullmann Condensation Reaction. II. Effects of the Medium, the Additives and the Substituents
Authors: Tuong Tran Dinh , Hida Mitsuhiko 
Published: July 2006

Abstract
The effects of the medium, the additives, and the oxidation state of the copper catalyst on the rate of the Ullmann condensation reaction of sodium 1-amino-4-bromoanthraquinone-2-sulfonate and aniline in an aqueous buffered solution were investigated. The reaction rate was not affected by the ionic strength but depended very largely on the hydrogen-ion concentration. It was also established that the reaction was retarded by the addition of anions which can coordinate to copper; the retarding effect was in the order: F−&lt;&lt;Cl−&lt;Br−&lt;I−&lt;CN−. The inhibiting effects of copper-chelating agents and oxygen were also observed. No marked difference, except a slight increase in initial rate, was observed when cuprous chloride was used as the catalyst instead of cupric sulfate. The effect of the substituents of aniline on the reaction rate can be expressed by Yukuwa-Tsuno’s equation, in which the parameters, ρ and r, were −2.20 and 0.50 respectively. The experimental results are discussed.
Calorimetric Study of the Glassy State. VI. Phase Changes in Crystalline and Glassy-Crystalline 2,3-Dimethylbutane
Authors: Adachi Keiichiro , Suga Hiroshi , Seki Syûzô 
Published: July 2006

Abstract
2,3-Dimethylbutane has two crystalline phases, high temperature form (crystal-I) and low temperature form (crystal-II). On account of the supercooling effect of crystal-I, its glassy crystalline state (non-equilibrium frozen-in state) is established below Tg (76 K) by rapid cooling. The heat capacities for various phases were determined from 13 to 300 K from principal interest in the thermodynamic properties of the glassy crystal. The transition temperature from crystal-II to crystal-I and melting point were determined to be 136.02 K and 145.05 K, respectively. The heats of transition and of fusion were determined to be 6427 J mol−1 and 788 J mol−1, respectively. From these data, the residual entropy and T2 temperature were determined to be 7.4 JK−1 mol−1 and 65 K, respectively. We also calculated the ratio of Tg to T2 for several glassy crystals known hitherto, which amounts to 1.15–1.20. The stabilization effect was studied by the measurement of the change of the configurational enthalpy in the glassy crystalline state. Also, we discovered a new meta-stable intermediate phase (crystal-III) in the course of irreversible transition from the supercooled crystal-I to crystal-II. The thermal properties of this phase were also studied and its residual entropy was determined to be 2.7 JK−1 mol−1.
Excitation of Sodium Atoms by Collisions with Vibrationally Excited Molecules behind Shock Waves
Authors: Tsuchiya Soji , Suzuki Isao H 
Published: July 2006

Abstract
Simultaneous measurements of Na D and CO fundamental emissions have been made behind a shock wave in CO–Ar or CO–N2–Ar mixture containing a trace of Na vapor. The relaxation of a population in each vibrational level is calculated by use of Montroll-Shuler equation. The Na D emission intensity behind the shock wave in the 1.5% CO+Ar mixture nearly follows the relaxation of CO molecules excited to a vibrational level v=3 or 4, which is energetically lower than the 32P state of Na. This means that most Na atoms are excited by collisions with CO molecules in a level higher than v=3, and that the Na D reversal temperature exceeds the vibrational temperature of CO molecules behind the shock wave. In contrast to this, excitation of Na behind the shock wave in the 1.7% CO+49.3% N2+49.0% Ar mixture is due to collisions with N2 molecules in a level higher than v=6, and a nearly resonant vibrational-to-electronic energy transfer is realized. The relative values of the exciting rate kve by collisions with CO or N2 in a level v are determined to be k1e :k2e :k3e k4e :k5e=&lt;0.01 : 0.04: 1 : 1.6 : &lt;2 for Na–CO and k4e :k5e :k6e :k7e :k8e=&lt;0.03 : 0.21 : 1 : 1.4 : &lt;2 for Na–N2 collisions at about 2600°K.
Semiconductivity and Photoconductivity of TCNQ Crystal
Authors: Hiroma Shoji , Kuroda Haruo , Akamatu Hideo 
Published: July 2006

Abstract
The results of a preliminary investigation on the semiconductive and photoconductive behaviors of the TCNQ crystal are described. The single crystal of TCNQ shows a resistivity of the order 1011 Ω·cm at room temperature with an activation energy of about 0.6 eV. The photoconductive sensitivity of a TCNQ crystal is comparatively high. There are two types of crystal with respect to sensitivity to visible light. In both cases, the low-energy tail is extended up to about 1.5 eV. It is shown that both the activation energy of photoconduction and the light-intensity dependence of photocurrent differ appreciably in visible and ultraviolet regions.
The Mössbauer Effect in Ethyltin Halides and Related Compounds
Authors: Watanabe Noriyuki , Niki Eiji 
Published: July 2006

Abstract
The Mössbauer spectra for ethyltin halides and related compounds (Et4Sn, SnX4 (X=Cl,Br, I), Et3SnX, Et2SnX2 (X=Cl, Br, I), EtSnI3) were obtained. The replacement of ethyl groups by halogen atoms made the isomer shifts more positive relative to the tetraethyltin precursor. These results may be explained in terms of the rehybridization theory that the s-character of a central atom tends to concentrate in orbitals directed toward electropositive substituents. A suggestion that the compounds of RSnX3 type show smaller quadrupole splittings than the R3SnX compounds is made and discussed in terms of the rehybridization in the orbitals of the tin atom and in terms of bond ionicity.