bluuebunny/crossref_metadata_2025 huggingface dataset:
Electronic Spectra of Biphenyl and Fluorene
Authors: Hoshi Toshihiko , Inoue Hiroyasu , Shiraishi Junko , Tanizaki Yoshie
Published: July 2006

The ultraviolet absorption spectrum of diprotonated-2,7-diaminofluorene has been divided into two components polarized along the long and the short axes of the molecule by using the results of the dichroic spectra in the stretched PVA sheet. By a comparison of the experimental results with those calculated by means of a semiempirical LCAO-ASMO-SCF-CI approximation including a variable β method the assignment of the absorption bands has been made. It has been found that the compound has five absorption bands above 210 mμ. The existence of the additional 300 mμ band of fluorene has been explained theoretically by increasing the ionization potentials of the 9- and 10-carbon atoms by 3 eV from the usual value (11.42 eV).
Isotopic Fractionation in a Thermal Ion Source
Authors: Kanno Hitoshi
Published: July 2006

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

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

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

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

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

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|>>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

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

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

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

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

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>TFA>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>TFA>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

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

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

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

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

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

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

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

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−<<Cl−<Br−<I−<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

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

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=<0.01 : 0.04: 1 : 1.6 : <2 for Na–CO and k4e :k5e :k6e :k7e :k8e=<0.03 : 0.21 : 1 : 1.4 : <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

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

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.
Polarized Absorption Spectra of TCNNQ-Aromatic Hydrocarbon Molecular Complexes
Authors: I’haya Yasumasa J , Yunoki Toru , Suzuki Noboru
Published: July 2006

Polarized absorption spectra of TCNNQ and TCNNQ-anthracene, pyrene, phenanthrene (Group 1), 1,2-benzanthracene, chrysene and triphenylene (Group 2) molecular complexes were measured in the frequency range of 13.5–42 kK at room temperature and 80°K. The mole ratio of donor to acceptor was found to be 2 : 1 for Group 1 complexes and 1 : 1 for Group 2 complexes. Two broad bands observed in each spectrum of these complexes were assigned to be the first and the second charge-transfer (CT) bands. The CT bands were enhanced in intensity and displaced to the red at 80°K. The first CT bands were confirmed to be associated with the charge transfer from the highest occupied molecular orbital (HOMO) of donor to the lowest vacant molecular orbital (LVMO) of acceptor. The charge transfer mechanism for the second CT bands may be divided into two classes; for Group 1 complexes it is mainly due to the second LVMO of acceptor, while for Group 2 complexes, in addition to this, there is a possibility of the charge transfer from the second HOMO of donor to the LVMO of acceptor.
The Polarized Absorption Spectra of Some α-Aminoanthraquinones
Authors: Inoue Hiroyasu , Hoshi Toshihiko , Yoshino Junko , Tanizaki Yoshie
Published: July 2006

The π–π* electronic absorption spectra of 1-amino-, 1,4-diamino-, and 1,4,5,8-tetraaminoanthraquinones were investigated by means of the polarized absorption spectra using stretched PVA sheets and theoretical calculations. Each of these compounds has four absorption bands in the near-ultraviolet region (210–340 nm) and one in the visible region. The bands of the aminoanthraquinones which appear in the visible region can be assigned to the intramolecular charge-transfer transitions associated with the charge migration from the ami no group to the carbonyl groups.
Symmetry Rule for Predicting Bond Distortions in Conjugated Hydrocarbons
Authors: Nakajima Takeshi , Toyota Azumao , Fujii Sadao
Published: July 2006

A symmetry rule for predicting molecular shapes which is based on the second-order Jahn-Teller effect has been applied to the predictions of bond distortions in a number of nonalternant hydrocarbons in their ground and electronically excited states. In spite of the very crude approximation that only the lowest-lying excited state plays a dominant role in determining the energetically most favorable nuclear displacement, a fairly clear-cut criterion for molecular-symmetry reduction was obtained. The actual types of the most soft bond distortions, determined by examining the two-center components of transition densities, are in good agreement with the results of variable bond-length SCF MO calculations and available experimental results. The problem of symmetry reductions possible in large cyclic polyenes C4n+2H4n+2 is briefly discussed.
Interaction of 1,2-Dichloroethane with Benzene and other Aromatic Hydrocarbons
Authors: Morita Akio , Takahashi Hiroaki , Higasi Keniti
Published: July 2006

Experiments to confirm Kubo’s conclusion on the complex formation of 1,2-dichloroethane with benzene were carried out following his procedure. Dielectric measurements were carried out with inert solvents hexane and cyclohexane. The interactions between 1,2-dichloroethane and each of the compounds toluene and p-xylene were also studied with inert solvents hexane, cyclohexane, and carbon tetrachloride. The results are discussed in relation to complex formation.
Radiolysis of Mixtures of Hydrocarbons and Ammonia. I. Formation of Ethylamine from a Mixture of Ethylene and Ammonia
Authors: Tokunaga Okihiro , Hamanoue Kumao , Okamoto Jiro , Danno Akibumi
Published: July 2006

The γ-radiolysis of a gaseous mixture of ethylene and ammonia has been investigated over the whole range of composition. The products of decomposition were primarily hydrogen, ethane, n-butane, ethylamine, and acetylene. It was observed that the yields of ethane, n-butane, and ethylamine increased with the increasing concentration of ammonia, and that the G-values of these products at 98 mol% ammonia were 0.52, 2.12, and 0.89, respectively. Addition of oxygen or nitric oxide as radical scavengers tended to reduce the yields remarkably. The G-value of ethyl radical was calculated from the G-values of ethane, n-butane, and ethylamine, and the limiting value of G(C2H5·) was determined by extrapolation to 100 mol% ammonia. The value thus obtained agrees with the initial G-value of hydrogen radical, i.e., GH=7.0±0.6, which was obtained by Eyre and Smithies in the study of the γ-radiolysis of ammonia gas. From these results, it was concluded that thermal hydrogen radicals produced by the γ-radiolysis react quickly with ethylene, giving ethane, n-butane, and ethylamine from ethyl radicals.
Preparation and Properties of Iron(II) Complexes with Tetraoxime Analogues
Authors: Bagkes Joseph , Masuda Isao , Shinra Koichiro
Published: July 2006

Three polymeric iron(II)-tetraoxime chelates of the formula CH3C(NOH)C(NOH)-R-C(NOH)C(NOH)-CH3, where R: C6H4-O-C6H4, C6H4-C6H4, and 2,6-pyridyl, are characterized and compared with monomeric α-dioxime analogues. Analytical data indicate that in the solid state these Fe-N4 type chelates do not coordinate an axial base. Axial substitution takes place only upon dissolution into pyridine or similar basic solvents. The resemblance between the substituted polymer chelates and the monomeric dimethylglyoxime compounds, as far as their electronic spectra are concerned, is discussed. While the solid state polymers are all paramagnetic with moments 2.0–2.5 B.M., ESR data show that in solution a conversion into a diamagnetic species takes place. A strong absorption band due to the O–N stretching vibration appears at about 1650 cm−1 upon complexing of the nitrogen atoms. The paramagnetism and the reflectance spectra of the solid state samples are related to their structure.
Kinetic Studies of the Electron-Transfer Reaction in Iron(II) and Iron(III) Systems. V. The Reaction in Mixed Solvents of Methanol and Water
Authors: Wada Goro , Endo Akiko
Published: July 2006

The electron-transfer reaction between Fe(II) and Fe(III) species in mixed solvents of methanol and water was investigated by the use of Fe-59 as the radioactive tracer. The hydrolysis constant of Fe3+, KH, in the mixed solvent decreases gradually as the mole faction of methanol, xM, increases. At very high acidities, ionic association between Fe3+ and ClO4− ions occurs, thus forming an ion-pair in the mixed solvent. The apparent rate constant, kapp, of the electron-transfer reaction is a function with respect to xM; kapp does not vary much in the concentration range xM≤0.3, but it decreases as xM grows higher than 0.3. kapp is also dependent upon [H+] and in a linear relationship with [H+]−1. Thus, the two reaction paths, Fe2+-Fe3+ (k0) and Fe2+-FeOH2+ (kH), are deduced to be prevailing. Both rate constants, k0 and kH, decrease with an increase in xM. The constancy of kapp at 0≤xM≤0.3 is a result of compensation between the increasing KH value and the decreasing k0 and kH values. By taking into account the values of ΔHH\eweq=7.6 kcal/mol and ΔSH\eweq=−19.1 e.u. at xM=0.2, both of which do not differ greatly from those in pure water, the reaction is concluded to proceed through the hydrogen-atom-transfer mechanism in the mixed solvent, the inhibiting effect of methanol being due to the reduction of the hydrogen bondings between water molecules.
The Reaction Mechanism of 2-Dimethoxymethyl-3-methoxypropionitrile with Acetamidine. I. A Revised Structure of the Intermediate
Authors: Nishino Takenori , Kiyokawa Masumi , Miichi Yoshiyuki , Tokuyama Kanji
Published: July 2006

The reaction of 2-dimethoxymethyl-3-methoxypropionitrile (1) with acetamidine yields 2,7-dimethyl-5,6-dihydropyrimido[4,5-d]pyrimidine (6) via an intermediate, λmaxMeOH 262 mμ. This intermediate has been identified as 2-acetamidinomethylene-3-methoxypropionitrile (5) without being isolated. However, this assignment seems to be somewhat inconsistent with the stabilities of an acetal group in basic media and with the UV spectra of compounds with structures similar to 5. The reaction of 1 with sodium methoxide gave a dimeric compound (8). This result suggests the formation of 2-dimethoxymethylacrylonitrile (2) in the initial stage of the reaction of 1 with acetamidine. The reaction of acrylonitrlie with acetamidine yielded 2-methyl-4-amino-5,6-dihydropyrimidine (23), whose UV spectrum in methanol showed its absorption maximum at 270 mμ in neutral media and at 258 mμ in basic media. Therefore, the structure of the intermediate may be concluded to be 2-methyl-4-amino-5-dimethoxymethyl-5,6-dihydropyrimidine (27) instead of 5, and the reaction may be concluded to proceed via the pathway of 1→2→27→6.
Synthesis of 5,5-Dimethyl-4-acetoxy-2-cyclopentenone, an Intermediate in the Total Synthesis of Illudin M, through Sulfur Compounds. A Novel Intramolecular Migration of Ethylenedioxy Group
Authors: Matsumoto Takeshi , Shirahama Haruhisa , Ichihara Akitami , Shin Hyonsobb , Kagawa Shohei
Published: July 2006

5,5-Dimethyl-4-acetoxy-2-cyclopentenone, an intermediate in the total synthesis of illudin M, has been prepared from 1-methylsulfinyl-3,3-dimethyl-4,4-ethylenedioxy-2-pentanone as well as from 1,1 -trimethylenedithio-3,3-dimethyl-4,4-ethylenedioxy-2-pentanone. An example of new intramolecular transketalization has been described.
Olefin Disproportionation by Rhenium, Tungsten, and Molybdenum Based Catalysts. Effect of the Addition of Oxygen
Authors: Uchida Yasuzo , Hidai Masanobu , Tatsumi Takashi
Published: July 2006

ReCl5 was activated with Et3Al and oxygen to give a catalyst effective for the disproportionation of α-olefins as well as internal olefins. The catalyst species was deactivated by excess oxygen. The catalyst system consisting of either WCl6 or MoCl5 and Et3Al exhibited disproportionation activity in a short range of Al/M (M=W or Mo) molar ratio. The activity decreased with the increase in the Al/M ratio, but was restored by the introduction of oxygen.
Stereochemical Studies and Synthetic Applications of Bis-β-keto Sulfoxides
Authors: Yamamoto Yasusi , Nozaki Hitosi
Published: July 2006

Bis-β-keto sulfoxides of the MeSOCH2CO(CH2)nCOCH2SOMe (n=7, 8, or 10) type are prepared. The dl and meso isomers are isolated, and the stereochemistry of bis-β-keto sulfoxides (n=8) is established by means of the asymmetric synthesis of the resolvable isomer from an optically-active ester, (−)-menthyl–O–CO(CH2)8–CO–O–(−)-menthyl, and methylsulfinylcarbanion. It is concluded that the higher-melting one is the meso isomer and that the lower-melting one is racemic. The condensation of bis-β-keto sulfoxides, MeSOCH2CO(CH2)8-COCH2SOMe, and allyl bromide in the presence of a base and the subsequent desulfurization give the olefinic ketone, (CH2=CHCH2CH2CO(CH2)4)2. Optically active sulfoxide, MeSOCH2COPh, is obtained from (−)-menthyl benzoate and methylsulfinylcarbanion.
The Preparation and Deamination of 1-t-Butyl-3-amino-, 1-t-Butyl-3-aminomethyl-, and 1-t-Butyl-2-aminomethylazetidine
Authors: Chen Teng-Yueh , Hung Mu-Huang , Chen Po-Tau , Ohta Masaki
Published: July 2006

1-t-Butyl-3-amino, 1-t-butyl-3-aminomethyl-, and 1-t-butyl-2-aminomethylazetidine were prepared by the ammonolysis of 1-t-butyl-3-azetidinyl tosylate, and by the reduction of 1-t-butyl-3-cyano, and 1-t-butyl-2-cyanoazetidine respectively. In the deamination, both of the first two azetidines gave only the corresponding alcohols, 1-t-butyl-3-azetidinol and 1-t-butyl-3-hydroxymethylazetidine, while the last one was found to afford two products, 1-t-butyl-2-hydroxymethylazetidine and 1-t-butyl-3-hydroxypyrrolidine. The deamination products were identified as the corresponding acetates.
The Substituent Effect. II. Normal Substituent Constants for Polynuclear Aryls from the Hydrolysis of Arylcarbinyl Benzoates
Authors: Sawada Masami , Tsuno Yuho , Yukawa Yasuhide
Published: July 2006

The rates of the alkaline hydrolysis of 9 polynuclear arylcarbinyl benzoates were measured in 70% (v/v) aqueous acetone at 25°C. The new set of σ0 values for polynuclear aryls was obtained, using the ρm value established by the hydrolysis of m- and p-substituted-benzyl benzoates. In the present reaction, it is possible to assume that the peri-hydrogen steric effect is practically absent, bacause o-tolyl derivative gives a σ0 a value comparable with that of p-tolyl, and 1-naphthyl with that of 2-naphthyl. The set thus obtained can be successfully described in terms of two components; self-atom polarizability and Streitwieser’s inductive index, ∑rij−1.
The Base-catalyzed Condensation of α-Haloaldehydes with Dichloroacetates
Authors: Takeda Akira , Tsuboi Sadao , Wada Satoshi , Kato Hiroshi
Published: July 2006

The reaction of aliphatic α-haloaldehydes with methyl dichloroacetate in the presence of sodium methoxide was carried out. α-Chloroaldehydes afforded 2,4-dichloro-2,3-epoxyalkanoates (5), whereas α-bromoaldehydes gave 2,2-dichloro-3,4-epoxyalkanoate (7). The attempted epoxy-carbonyl rearrangement of 5 with hydrogen chloride or thionyl chloride failed. The thermal decomposition of methyl 2,4-dichloro-2,3-epoxynonanoate (5c) at 300–400°C afforded methyl 3-chloro-2-oxo-3-nonenoate (9c), and the similar treatment of methyl 2,4-dichloro-4-methyl-2,3-epoxypentanoate (5a) afforded a mixture of methyl 3,4-dichloro-4-methyl-2-oxopentanoate (6a), methyl 3-chloro-4-methyl-2-oxo-3-pentenoate (9a), and methyl 3-chloro-4-methyl-2-oxo-4-pentenoate (10). The treatment of 5 with thiourea in methanol gave the thiazole derivative (15), but neither sodiomalonate nor sodioacetoacetate reacted with 5.
The Accelerated Reaction of 2,2-Diphenyl-1-picrylhydrazyl with Cupric 3-(1-Butenyl)-2,4-pentanedionate in Frozen Solutions and Its ESR Spectra
Authors: Uehara Kaku , Kamei Kiyohiro , Tanaka Makoto , Murata Niro
Published: July 2006

The rate enhancements upon freezing in the reaction of 2,2-diphenyl-1-picrylhydrazyl (DPPH) with cupric 3-(1-butenyl)-2,4-pentanedionate (3-α-butenylacetylacetonate) were studied in benzene, dioxane, and cyclohexane. It was observed that the degree of the rate enhancements in frozen solutions varied remarkably with the kind of solvent. The order of the accelerating effect was as follows: benzene>dioxane>cyclohexane. Upon freezing, the hyperfine structure in the ESR spectra of DPPH collapsed into a single line, but the peak-to-peak line width (ΔHpp) changed appreciably with the solvents used. The order of the values of ΔHpp was as follows: cyclohexane>dioxane>benzene. These results suggest that the enhancement of the rate in a frozen solution is due to the increased concentration of reactants in the liquid region existing among the crystalline solvents.
Ionic Decomposition of Phenylazotriphenylmethane in Trifluoroacetic Acid
Authors: Kamigata Nobumasa , Kobayashi Michio , Minato Hiroshi
Published: July 2006

Acid-catalyzed decomposition of phenylazotriphenylmethane was studied in mixtures of benzene and large excess concentration of trifluoroacetic acid. The decomposition was of first order and the rate was much faster than that in pure aromatic solvents. The values of activation energy (Ea=22.3 kcal/mol) and activation entropy (ΔS\eweq=−5.2 e.u) fit the isokinetic relationship established for the ionic decomposition of benzenediazonium tetrafluoroborate in aprotic polar solvents and of phenylazo p-tolyl sulfone in mixtures of benzene and trifluoroacetic acid. The reaction products were benzene, biphenyl, benzophenone, triphenylmethane, triphenylmethyl alcohol and nitrogen. Orientations and partial rate factors for the phenylation of monosubstituted benzenes indicated that not phenyl radical but phenyl cation was produced as an intermediate. Further, the UV spectrum of PAT in benzene and trifluoroacetic acid shows λmax at 403 mμ (logε 4.48) and λmax at 427 mμ (logε 4.48). However, the UV spectrum of PAT in benzene and in the absence of trifluoroacetic acid has no absorption in this range. The formation of triphenylmethyl alcohol and the UV spectra of PAT in acid solution indicate that triphenylmethyl cation was formed as an intermediate. A plausible mechanism was discussed.
Electrochemical Fluorination of N-Nitrosodiethylamine
Authors: Watanabe Nobuatsu , Haruta Masatake , Chang Byongte
Published: July 2006

The fluorination of (C2H5)2N–NO at a nickel anode under a variety of operating conditions resulted in the formation of liquid products such as (CF3)2C2F5N, (C2F5)2CF3N, (C2F5)3N, and the compounds containing C–N groups together with gaseous fragmentation products such as CF4, C2F6, CHF3, NF3, and N2. Current efficiency of total gaseous products increased appreciably as the concentration of substrate and current density became higher. Effect of electrolysis temperature was so characteristic as observed in the fluorination of triethylamine that there existed the temperature at which a maximum value of current efficiency was given. On the basis of both the experimental results on the effects of operating conditions and the electrochemical measurements in hydrogen fluoride solutions of Et2N–NO, mechanism of the fluorination reaction was discussed and compared with those of diethylamine and triethylamine.
Bromination of Aliphatic Ketones with Copper(II) Bromide in Organic Solvents. I. The Reaction of Acetone with Copper(II) Bromide in Methanol
Authors: Kojima Yoshitane , Kawaguchi Shinichi
Published: July 2006

The reaction between acetone and methanol to form acetone dimethylacetal attains equilibrium quickly under the influence of copper(II) bromide. Reaction of both acetone and acetone dimethylacetal with copper(II) bromide thus proceed simultaneously to produce copper(I) bromide, hydrogen bromide, and brominated substrates. The mass balances of these reactions were established. On account of the retarding effect of copper(I) bromide and the enhancing effect of hydrogen bromide, the time course of reaction is too complicated to be analyzed, and the initial rate formula was determined. Two reaction pathways were suggested and copper(II) bromide was considered to play dual roles as a catalyst and a brominating agent in either case. The acid catalyzed reactions were also found to follow a two-term rate law, one being independent of and the other first order with respect to copper(II) bromide.
Radiolyses of Mixtures of Ammonia and Hydrocarbons. II. Formation of Hydrogen from Mixtures of Ammonia and Olefins (Ethylene, Propylene and Butadiene)
Authors: Hamanoue Kumao , Okamoto Jiro , Tokunaga Okihiro , Danko Akibumi
Published: July 2006

γ-radiolyses of gaseous mixtures of ammonia and olefins (ethylene, propylene and butadiene) have been investigated over the whole composition range of mixtures, and consideration was given on the primary processes of hydrogen formation. From the extrapolated values of G(H2) obtained in the γ-radiolyses of the mixture of ammonia and olefins, it was found that the non-scavengeable G(H2) of ammonia, ethylene, propylene and butadiene were 0.68–0.72, 1.26, 1.06, and 0.33, respectively. Gas-phase radiolyses of ammonia-perdeuterated olefin mixtures have also been investigated. From kinetic calculation on the data of isotopic mixtures of hydrogen, the following results were obtained; 1) both thermal and non-scavengeable hydrogen molecules are produced by the γ-radiolysis of ammonia, and the non-scavengeable hydrogen molecules are produced for the most part by a unimolecular process, 2) almost all the hydrogen molecules produced by the γ-radiolyses of olefins (ethylene, propylene, and butadiene) are non-scavengeable; a unimolecular process plays an important role in the case of ethylene, and in other cases a bimolecular process. G(H2) of the butadiene radiolysis is very small compared with that of other olefins and with the calculated value of butadiene, i.e., G(H2)<1. The discrepancies can be interpreted in terms of the addition reaction of the “hot” hydrogen radicals to butadiene to form t-2-butene.
The Amine Sensitization of the Fluorescence of Tris-(dibenzoylmethano)europium(III)
Authors: Fukuzawa Tadashi , Ebara Nozomu
Published: July 2006

The effect of amines on the efficiency of fluorescence of tris(dibenzoylmethano)europium(III) has been investigated in a methanol solution. Amines with low pKb values seem to form 1 : 1 complexes with the chelate, and the change in the fluorescence intensity of the chelate is due exclusively to the formation of a complex, which fluoresces more strongly than the chelate itself. It seems that the sensitization of the fluorescence is due to the change in the relaxation lifetime. In the case of amines with aromatic moieties, sensitization through energy transfer may also take place, but this never occurs unless the amine molecule is present in the complex. The structure of the complex and the mechanism of sensitization are discussed.
Acidity and Acid Strength of Zeolite Catalysts
Authors: Ikemoto Misako , Tsutsumi Kazuo , Takahashi Hiroshi
Published: July 2006

The influence of pretreatment temperature, silica-to-alumina mole ratio, the kind of cation and degree of cation exchange on the number of acid sites, and the acid strength of zeolite catalysts were examined by means of amine titration. Strong acid sites whose H0 function is lower than −8.2 were analyzed by ultraviolet spectroscopy. Though H-zeolites have fairly strong acid sites (−10.8<H0<−8.2), the number of acid sites decreases with the decrease of the silica-to-alumina mole ratio, as a result of the collapse of the zeolite structure. Ca-zeolites have an acid site distribution similar to that of H-zeolites only when the silica-to-alumina mole ratio is larger than 4.6. Only La-form Y-zeolite has strong acid sites (H0<−10.8). When the degree of La-exchange exceeds 85 mol%, zeolite shows an acid coloration even with dinitrotoluene with pKa−12.8.
A Theoretical Consideration of the Electron-scavenging Process In Liquid Hydrocarbons. III. Integral Transforms of the Distribution Functions
Authors: Yamazaki Hideo , Shinsaka Kyoji
Published: July 2006

The relations of integral transforms between various distribution functions are discussed using the potential control approximation ignoring the diffusion term in the Smoluchowski equation; the initial spatial distribution of the electron-ion pair or the initial distribution of electrons from the central ion core in a spur, χ(r, 0); the relative G-value of electron recombination, G(ksCs) as a function of the concentration of the scavenger and the rate constant; the time dependence of the electron concentration, N(t), after pulse irradiation; and the relaxation time spectrum, K(n), of the decay of the electron concentration after pulse irradiation or of the weight function, K(n), in the initial exponential distribution of thermalized electrons in a spur are shown to be connected by the square diagram of Laplace transforms:

(Remark: Graphics omitted.)

By the use of this relation, the various distribution functions are evaluated from the empirical formulas of G(ksCs) proposed by Schuler et al. and by Hummel.
Equilibrium of Urea Synthesis. I.
Authors: Inoue Shigeru , Kanai Kazumichi , Otsuka Eiji
Published: July 2006

A test of the equilibrium conversion of CO2 to urea was carried out using a batch autoclave. Some results different from those reported by Frèjacques were obtained, as was expected from the latest data on commercial urea plants. The equilibrium conversion reached its maximum value at about 195°C by 5–15% higher than that reported by Frèjacques. On the contrary, at temperatures above 200°C the value was lower, and falled rapidly with the raise of temperature. This phenomenon may be due to the mechanism of the equilibrium of urea synthesis, and not to the experimental method, as our sampling was made directly from the liquid phase. The equilibrium conversion, x, may be expressed with respect to NH3/CO2, a, H2O/CO2, b, and temperature, t, as

(Remark: Graphics omitted.)

Therefore, a limited conversion exists in the conventional urea process.