bluuebunny/crossref_metadata_2025 huggingface dataset:
A Study of Inorganic Ion-exchangers. VIII. The Synthesis of the Crystalline Zr(RNH)xH2−x(PO4)2·yH2O and Their Characteristics (R=(CnH2n+1)3 and C5H5, n=1–6)
Authors: Kobayashi Etsuro , Shin Shigemitsu
Published: July 2006

The synthesis of microcrystalline compounds with the formula of Zr(RNH)xH2−x(PO4)2·yH2O (R=(CnH2n+1)3, C5H5, n=1–6, x=0.1–0.6, y=1–3) and their characteristics have been investigated. The compounds were formed by means of a hydrothermal reaction between RNH·H2PO4 and ZrOCl2 in the mole ratio of 4:1 at 130–180 °C. The layer-spacings of the trimethyl-, triethyl-, tripropyl-, tributyl-, tripentyl-, trihexylamine, and pyridine phosphates were 9.9, 13.0, 13.6, 17.0, 16.5, 18.4, and 10.9 Å respectively. In the thermal decomposition of each phosphate, the water of crystallization was eliminated at 105–130 °C. The organic base group in the alkylamine phosphates was burned in the presence of air at 330–360 °C, but this combustion was imperfect in the case of pyridine phosphate. The phosphates condensed at 400–450 °C. Zr(RNH)xH2−x(PO4)2·yH2O was also obtained by means of an ion-exchange reaction between γ-Zr(HPO4)2·2H2O and the corresponding tertiary amine. In these products, the layer-spacings of the trimethyl-, triethyl-, tripropyl-, tributyl-, tripentyl-, and trihexylamine phosphates were 17.6, 16.4, 16.7, 21.0, 21.5, and 23.2 Å respectively, while those of pyridine and piperidine phosphates were 12.4 and 18.4 Å respectively. The layer-spacings of the products increased roughly with the size of the guest molecules. When Zr(RNH)xH2−x(PO4)2·yH2O was treated with HCl, the products from the hydrothermal reaction changed to α-Zr(HPO4)2·H2O, while the products from the ion-exchange reaction returned to γ-Zr(HPO4)2·2H2O the raw material.
Synthesis and Stereoisomerization of Intra- and Intermolecularly Bridged Indigo
Authors: Omote Yoshimori , Tomotake Atsushi , Aoyama Hiromu , Nishio Takehiko , Kashima Choji
Published: July 2006

The intramolecularly bridged N,N′-azelaoylindigo (3) and N,N′-sebacoylindigo (4) have been synthesized from indigo and the corresponding dichloride. The intermolecularly bridged N′,N″-sebacoylbis(N-acetylindigo) (5) has been synthesized from N-acetylindigo and sebacoyl dichloride. The relative rates of the cis-to-trans thermal isomerization of 3, 4, and 5, compared with that of N,N′-diacetylindigo (1c), were as follows: 3, 0.77; 4, 3.9; 5, 1.4; 1c, 1.0.
Selective Hydrogenation of Cyclopentadiene to Cyclopentene Using Colloidal Palladium Supported on Chelate Resin
Authors: Hirai Hidefumi , Komatsuzaki Shigeru , Toshima Naoki
Published: July 2006

Cyclopentadiene was hydrogenated to cyclopentene selectively by using colloidal palladium supported on chelate resin with iminodiacetic acid moieties as a catalyst. The catalyst, containing metal particles of 1–6 nm in diameter, was prepared by reduction of the palladium(II)–chelate resin complex with methanol. Cyclopentene was produced in 97.1% yield at 100% conversion of cyclopentadiene at 30 °C under 1 atm of hydrogen. This value in yield was also achieved on repeated uses of the catalyst. The hydrogenation rate was correlated to the polarity parameter, ET(30) values, of the solvents used in the reaction, except in the case of dimethyl sulfoxide. The hydrogenation rates of cyclopentadiene (RD) and cyclopentene (RE) were expressed as RD=kD[H2][catalyst] and RE=kE[H2][cyclopentene][catalyst], respectively, where kD and kE are the rate constants. The equilibrium constant for complex formation between cyclopentadiene and the catalyst, KD, was estimated to be over 400 times larger than that between cyclopentene and the catalyst, KE. A mechanism, including the coordination of olefins to the catalyst and the subsequent hydrogenation of the coordinated complexes, was proposed.
Influence of Boric Acid on the Hydrolysis Rate of a Hydroxy Schiff Base
Authors: Matsuda Hiroshi , Nagamatsu Hiroaki , Okuyama Tadashi , Fueno Takayuki
Published: July 2006

Effects of boric acid on the rate of hydrolysis of a Schiff base derived from α-hydroxyisobutyrophenone and 2-methoxyethylamine were examined in the pH range 4.2–10.4 at 30 °C. The rate increased above pH 7 but decreased below pH 7 with increasing borate concentration following a saturation curve. This is consistent with a reaction sequence involving a preequilibrium formation of a borate–substrate complex followed by its rate-determining decay to the hydrolysis products. The formation constant of the complex showed a bellshaped change with pH but the rate constant for the complex decay was constant above pH 7, a small change being observed at lower pH. A mechanism involving an intramolecular transfer of the boron-coordinated hydroxide ion to the imine carbon within the complex is presented. Hydrazone formation from the hydroxy ketone was also examined in the presence of boric acid.
Linear Dependence of ODMR Transition Frequency on T1→S0 Transition Energy. p-Dichlorobenzene in Various Matrices
Authors: Iwasaki Noriko , Kinoshita Minoru
Published: July 2006

The linear dependence of ODMR transition frequency on the T1→S0 transition energy of p-dichlorobenzene in various matrices was interpreted with the spin-orbit couplings of the lowest triplet state with the triplet and singlet manifold, by assuming that the matrix dependent shifts in the triplet and singlet state energy are correlated with each other.
A Study of the Thermal Decomposition of Ruthenium Ammine Zeolites
Authors: Tatsumi Takashi , Maekawa Wataru , Tominaga Hiro-o
Published: July 2006

Treatment of Ru(II) ammine–NaY under nitrogen at 100 and 300 °C leads to formation of [Ru(NH3)5N2]2+–NaY and metallic RU–N2, respectively. The effect of atmosphere and the type of Ru ammine complexes and zeolites on the decomposition behavior is discussed.
Immunoassay Using a Metal-complex Compound as a Chemiluminescent Catalyst. III. Flow-through Analysis of a Labeled Antigen Bound by Immune Reaction
Authors: Hara Tadashi , Toriyama Motohiro , Tsukagoshi Kazuhiko
Published: July 2006

By measuring the chemiluminescence intensity by the flow-through method rather than the conventional batchwise method, the sensitivity and precision of immunoassay and the time required for the measurement of the chemiluminescence intensity were improved as follows: 20 ng–50 μg of human albumin per tube, 5.8–7.2% (n=9) coefficient of variation, and 4 min measuring time.
Sodium Dibutyldiselenocarbamate. Analytical Application to the Extraction Spectrophotometry of Heavy Metals
Authors: Honjo Takaharu
Published: July 2006

Sodium dibutyldiselenocarbamate is soluble in water, and the form of its dibutyldiselenocarbamic acid is extractable by methylene dichloride; more than 99% of the reagent exists in the methylene dichloride phase in the pH region of 4–10. The reagent readily forms extractable chelates with AuIII, CoII, CuII, HgII, NiII, PdII, and ZnII while it gives considerable white precipitates with AgI and HgII in the pH region of 1–7. Each chelate in methylene dichloride absorbs at wavelengths lower than 400 nm. The peak of the copper(II) chelate with the molar absorbtivity of 1.50×104 at 442 nm is not affected by the spectra of the reagent and other metal chelates, and it can be used for the selective spectrophotometric determination of copper(II) up to 0–10 μg/cm3.
The Crystal Structure of Calcium Sulfite Tetrahydrate. Interatomic Distances and Angles
Authors: Matsuno Takashi , Takayanagi Hiroaki , Furuhata Kimio , Koishi Masumi , Ogura Haruo
Published: July 2006

Detailed geometries of the sulfite ions and of the oxygen-coordinations around the calcium ions in calcium sulfite tetrahydrate were determined based on the results of the X-ray analysis. It was revealed that the structure consists of two alternating layers, one consisting of calcium ions and water molecules, and the other consisting of sulfite ions and water molecules.
Acid Catalysis of the Denitrosation of N-Methyl-N′-cyclohexyl-N-nitrosothiourea
Authors: Isobe Masayoshi
Published: July 2006

The kinetics of denitrosation of N-methyl-N′-cyclohexyl-N-nitrosothiourea has been studied in the range of pH 3.45–3.73 using four organic acids; acetic acid, formic acid, chloroacetic acid, and cyanoacetic acid. Analyses of the kinetic data including the Brönsted plots have shown that the reaction is subject to a general acid catalysis.
Synthesis and Physicochemical Properties of Dioxathia[n]ferrocenophanes
Authors: Akabori Sadatoshi , Shibahara Sumio , Habata Yoichi , Sato Masaru
Published: July 2006

The reaction of 1,1′-bis(2-chloroethoxy)ferrocene with 1,2-ethanedithiolate in absolute ethanol gave mononuclear 1,10-dioxa-4,7-dithia[10]ferrocenophane and binuclear 1,10,21,30-tetraoxa-4,7,24,27-tetrathia[10,10]ferrocenophane, along with a small amount of unexpected 1,13-dioxa-4,7,10-trithia[13]ferrocenophane and 1,16-dioxa-4,7,10,13-tetrathia[16]ferrocenophane. Extraction of aqueous metal picrates (M; alkali, alkaline earth, Ag+, Tl+, Cd2+, Co2+, Cu2+, Ni2+, and Hg2+) with dioxathia[n]ferrocenophanes was examined and also with the corresponding ring membered polyoxa[n]ferrocenophanes. Dioxathiaferrocenophanes showed a highly selective extraction ability towards bivalent mercury and copper ions.
Effect of Temperature on the Polarographic Catalytic Current Produced by Proteins in the Presence of Cobalt Salts
Authors: Kano Kenji , Tokimitsu Ichiro , Ikeda Tokuji , Senda Mitsugi
Published: July 2006

The effect of temperature on the polarographic catalytic hydrogen evolution current (Brdicka current) produced by ribonuclease-A in an ammoniacal buffer containing cobalt salt has been studied using the theoretical equation of Brdi\`{c}ka current. With increasing temperature, the Brdicka current at −1.3 V increased between 10 and 30 °C then fell off above 30 °C, whereas the currents at −1.4 and −1.5 V decreased continuously. Analysis showed that the initial increase of the Brdicka current at −1.3 V was only apparent and that the Brdicka current constant, kB, which represents the catalytic activity of the protein, always decreased with increasing temperature in the potential range of −1.3 to −1.5 V. Further analysis has revealed that the intrinsic catalytic activity of the protein-cobalt(0) complex, which is transiently formed on the electrode surface and which catalyzes the hydrogen evolution, increases with increasing temperature whereas the life time of the complex decreases and the latter decrease cancels the former increase, resulting in the decrease of the kB value with increasing temperature.
Kinetic Studies of the Complex Formation in the System of Cyclodextrin, Iodine, and Iodide
Authors: Sano Takayuki , Yamamoto Masako , Hori Hiroka , Yasunaga Tatsuya
Published: July 2006

Kinetic studies of complex formation in the system consisting of cyclodextrin, iodine, and iodide have been made by the temperature-jump method. By addition of α-cyclodextrin to the iodine–iodide solution, a new relaxation in addition to that due to I62−, formation was observed, but not in the case of addition of β-cyclodextrin. The reciprocal relaxation time is independent of the iodine concentration, but increases with increase of both iodide and α-cyclodextrin concentration, with a tendency to reach a constant value at their high concentrations. From these concentration dependences of the relaxation time, the observed relaxation was assigned to the conformational change of the complex between α-cyclodextrin and iodide ion, and the rate constants were estimated to be 5.9×105 and 1.2×105s−1 for the forward and backward processes, respectively. A rationalization for the difference between α-cyclodextrin and β-cyclodextrin in this complex formation is proposed in terms of the molecular structure of cyclodextrin.
Competition between Hydrogen Fluoride and Hydrogen Chloride Molecular Elimination Channels in the Infrared Multiple-photon Decomposition of 1,2-Dichloro-1,1-difluoroethane
Authors: Ishikawa Yo-ichi , Arai Shigeyoshi
Published: July 2006

Time-resolved infrared emission spectra have been measured in the infrared multiple-photon decomposition of CClF2CH2Cl. The spectra were composed of emissions attributable to vibrationally excited HF* and HCl*. The emission yield of HF* increased rapidly with an increase in the fluence, while the yield of HCl* showed a maximum at 20 J cm−2. These results suggest that the HF and HCl molecular elimination channels compete with each other in the unimolecular decomposition of highly vibrationally excited parent molecules. The stochastic trajectory calculations provided a satisfactory description of the fluence dependences of the HF and HCl yields observed here for CClF2CH2Cl and previously for CHClFCHClF.
ESR in Mercury(II) Iodide Thiocyanate
Authors: Takei Kunio , Sugihara Kazuo , Hagiwara Hitoshi , Nakamura Seisuke
Published: July 2006

Powder of mercury(II) iodide thiocyanate (HgISCN) gives a weak electron spin resonance (ESR) signal at g=2.003 in the dark. When the powder is irradiated, the ESR-signal intensity increases during the exposure. When the light is turned off, the intensity decreases. The ESR-signal may be due to electrons trapped by lattice defects.
The Laser-flash Photolysis of Propanone, Butanone, and 2-Pentanone. Study of Triplet Decay Processes in Aliphatic Carbonyl Compounds
Authors: Naito Ikuo , Schnabel Wolfram
Published: July 2006

The laser-flash photolysis of propanone, butanone, and 2-pentanone were carried out in dichloromethane (265 nm, 15 ns flash duration). The emission spectra (fluorescence, phosphorescence, and P-type delayed fluorescence) and the transient absorption spectra (triplet state and acetyl radical) were recorded. From the decays of the emission and the absorption, the unimolecular (triplet decay) and bimolecular (T–T annihilation and self quenching) reaction-rate constants were determined. Oxygen quenched the triplet states with a diffusion-controlled rate constant (kO2=ca. 3×10 dm3mol−1 s−1).
Studies of Bitter Peptides from Casein Hydrolyzate. IX. Syntheses and Bitter Taste of Bitter Peptide BPIa Dimer, (Arg–Gly–Pro–Pro–Phe–Ile–Val)2, and Gly–Gly BPIa Derivatives
Authors: Miyake Ichizo , Kouge Katsushige , Kanehisa Hidenori , Okai Hideo
Published: July 2006

In order to elucidate the relationship between taste exhibition and chemical structure of bitter peptide BPIa, di–BPIa, Gly–Gly–BPIa, BPIa–Gly–Gly, and Gly–Gly–BPIa–Gly–Gly were synthesized. All of the peptides possessed a strong bitter taste of the same level as that of BPIa. In addition, the CD curves of the peptides were similar to that of BPIa. The results suggested that their spatial structures are essentially similar and that the whole molecular shape of BPIa contributes to its bitterness.
Specific Generation of Lithiated 3-Trimethylsiloxy-1,2-propadiene Derivatives from 1-(Trimethylsilyl)propargyl Alcohols
Authors: Kato Masahiro , Kuwajima Isao
Published: July 2006

1-(Trimethylsilyl)propargyl alcohols have been prepared by treating acyltrimethylsilanes with magnesium acetylides, and their base-induced reactions involving rearrangement of silyl group have been examined. Treatment of the alcohol with an equimolar amount of butyllithium in hexane followed by addition of tetrahydrofuran has allowed to generate the lithiated 3-trimethylsiloxy-1,2-propadiene, which reacts with an alkyl iodide to afford the alkylated 1-trimethylsiloxy-1,2-propadiene in high yield. Further, a catalytic amount of butyllithium also effects an efficient conversion of the alcohol to the corresponding 1-siloxy-1,2-propadiene through a similar rearrangement process.
A Consideration on the Structure of the Nascent Fibril Produced by Acetobacter xylinum
Authors: Kai Akira
Published: July 2006

The structure of the nascent fibril produced by Acetobacter xylinum was examined by electron microscopy and resistance to alkali. It was found that the inner part of the fibril after production is stained uniformly with sodium tungstophosphate. This suggests that the nascent fibril is in an amorphous state. Moreover, the fact that in the amorphous fibril microscopic fibrils with closely similar widths always appear in the course of time and that the X-ray diffraction diagram of the never-air-dried fibril treated with 11 wt% aqueous NaOH solution show cellulose I not cellulose II diffraction patterns, indicate that the arrangement of cellulose chains in its cross section can transform easily to that of chains in ellulose I crystalline. For such an arrangement, it must be presumed that in the nascent fibril cellulose chains are in the form of sheets of monomolecular layers corresponding to the (1\bar10) plane of cellulose I crystalline.
Silent Electric Discharge in the Equimolar Dihydrogen-Carbon Monoxide Mixture
Authors: Hata Sintaro , Hiramoto Koji , Katoh Katsuaki , Sasaki Kazuo
Published: July 2006

The purpose of this paper is focused on seeking the possibility of utilizing electric discharge in H2–CO mixtures as a mean of industrial processes. Along this line, the silent discharge in the equimolar mixture of CO and H2 has been studied as a function of both the flow rate of reacting gas mixture and the length of the discharge tube. The yield of formaldehyde, the main product, increased t with increasing flow rate of gas. At a given flow rate, however, the yield increased with increasing tube length indicating that the selectivity of formaldehyde can be increased steadily by increasing the rate of gas flow. The best value of the formaldehyde selectivity was 34% at the shortest residence time (0.25 s). Improvement of this value seems to be promising.
A Novel Beckmann Fission Reaction of 2-Aminocyclohexanone Oxime
Authors: Sato Haruyo , Imamura Shinzo , Kitano Yukishige
Published: July 2006

2-(4-Cyanobutyl)-4,5,6,7-tetrahydrobenzimidazole was obtained by treating 2-aminocyclohexanone oxime with ethyl acetimidate hydrochloride in acetic acid at below 50 °C, though only 2-methyl-4,5,6,7-tetrahydrobenzimidazole was produced by the reaction of 2-aminocyclohexanone oxime and free ethyl acetimidate in neutral solvents. A novel Beckmann fission reaction of dimeric 2-aminocyclohexanone oxime is presumed to participate in the formation of 2-(4-cyanobutyl)-4,5,6,7-tetrahydrobenzimidazole.
Chemical-state Analysis by Means of Soft X-Ray Spectroscopy. II. Kβ Spectra for Phosphorus, Sulfur, and Chlorine in Various Compounds
Authors: Taniguchi Kazuo
Published: July 2006

The phosphorus-, sulfur- and chlorine-Kβ spectra in various compounds are obtained by means of secondary excitation using a simple quasi-two-crystal X-ray spectrometer. The spectra thus obtained change depending upon the chemical state. The spectra are discussed from the point of view of chemical-state analysis. The spectral features are especially influenced by the hydrogen and oxygen of the ligand. The peak on the lower-energy side appears to be related to the oxygen, and the peak grows with an increase in the oxidation number. The spectrum gives information on the structural formula.
Nonisothermal Crystallization of Poly(tetrafluoroethylene)
Authors: Ozawa Takeo
Published: July 2006

Crystallization of poly(tetrafluoroethylene) was observed by differential scanning calorimetry at constant cooling rates. A method for kinetic analysis of thermoanalytical data of nonisothermal crystallization was applied to analyze the data, and it was elucidated that poly(tetrafluoroethylene) crystallizes one-dimensionally from preexisting nuclei, which are presumably impurities. These results are in accordance with electron-microscopic observation of the crystalline morphology of poly(tetrafluoroethylene), which consists of band-like or star-like crystallites. The kinetic parameters, especially the temperature dependence of the linear growth rate, were estimated.
Furan Ring Formation in OH-initiated Photooxidation of 1,3-Butadiene and cis-1,3-Pentadiene
Authors: Ohta Tomohiro
Published: July 2006

Reactions of hydroxyl radicals with 1,3-butadiene and cis-1,3-pentadiene in the presence of oxygen were studied in the gas phase. Two OH radical sources were employed; photolysis of H2O2 at 254 nm and photolysis of methyl nitrite at 360 nm. In the reaction system for 1,3-butadiene, furan was detected besides acrylaldehyde and in the cis-1,3-pentadiene system, 2-methylfuran was detected besides acetaldehyde, acrylaldehyde, and crotonaldehyde by gas chromatographic analysis. Approximate yields of furan and 2-methylfuran were 5.3–6.7% and 6.7–8.4%, respectively, which were sensitive to the conditioning of the surface of reactor but insensitive to hydroxyl radical sources, the surface material of reaction vessel or the surface to volume ratio of reactors. The yields of aldehydes were also measured. Isotopic labeling experiment with 18O2 by use of mass spectrometry indicated that abstraction of vinyl–hydrogen from 1,3-butadiene and cis-1,3-pentadiene occurred about 3% of the time. Photooxidation of 2,5-dihydrofuran initiated with ·OH radicals was also discussed to explain the increase of furan in the dark after the irradiation.
Adsorption Properties of Pillar Interlayered Montmorillonite
Authors: Matsumoto Mutsuyoshi , Suzuki Minoru , Takahashi Hiroshi , Saito Yasukazu
Published: July 2006

From analyses of Langmuir-type isotherms and αs-plots for nitrogen adsorption, both the micropore volume and the external surface area have been determined for pillar interlayered montmorillonite (abbreviated as PILM) prepared by intercalating the polynuclear Al cation into the montmorillonite interlayer. The applicability of the Gurvitsch rule to microporous PILM samples was confirmed for adsorption of heptane, whereas the adsorbed amounts of polar adsorbates were dependent on dehydrated states of the alumina pillar. High density of benzene in the micropore independent of calcination temperature suggests some peculiar orientation of benzene in the adsorbed state due to its molecular shape. The interaction of a water molecule with the adsorption site is weak and dependent on the calcination temperature of PILM samples. On this basis, the inhibition of rehydration of the alumina pillar has been discussed.
Basic Properties of MgO Doped with Alkaline Metal Compounds
Authors: Matsuda Tsuneo , Sasaki Yo , Miura Hiroshi , Sugiyama Kazuo
Published: July 2006

Basic properties of MgO doped with NaOH, KOH, and Li2CO3 which was calcined at 550, 700, and 900 °C in air were examined. The basicity of the catalysts was determined from the irreversible amount of adsorption of phenol and BF3, followed by evacuation at room temperature (for both adsorbates), 100, 200, and 300 °C (for phenol) after adsorption at room temperature. A good correlation was observed between the amount of phenol remained after evacuation at higher temperature than 200 °C and that of BF3. By doping of 1 wt% of alkali metal compounds in MgO the isomerization activity of 1-butene was enhanced, but by 10 wt% the activity remarkably decreased.
An Inspection of the Purity of Helium Used as the Carrier Gas in Pulse-adsorption Experiments
Authors: Miura Hiroshi , Narita Toshiyuki , Haruta Makoto , Sugiyama Kazuo , Matsuda Tsuneo
Published: July 2006

A novel method is proposed to inspect the oxygen content of the helium used as the carrier gas in pulse-adsorption experiments. The oxygen is first adsorbed on Pt/SiO2 catalyst and then titrated by CO pulses. This method is very simple and requires only a conventional pulse-adsorption system.
Tetrabromooxomolybdate(V) Complex. The Catalytic Reactivity for the Reaction of t-Butyl Hydroperoxide
Authors: Kurusu Yasuhiko , Masuyama Yoshiro , Saita Mikio
Published: July 2006

The nature of an ammonium counter cation of tetrabromooxomolybdate complex influences the rate of decomposition of t-butyl hydroperoxide(t-BuOOH) and oxidation with t-BuOOH. The catalytic activity of the ammonium for the decomposition of t-BuOOH decreased as the following order; benzyltrimethylammnium, –N-methyl pyridinium, –trimethylene bispyridinium, >>pyridinium, –quinolinium, >1,3-propanediammonium, −1,6-hexanediammonium. However, the reverse order was observed in the catalytic activity for the epoxidation by t-BuOOH, and the rate of oxidation of alcohol by t-BuOOH was independent of the nature of ammonium cation.
The Syntheses of the Corticoid Side-chain. II. A New Synthesis of 17α,21-Dihydroxypregna-1,4-diene-3,20-dione 21-Acetate from 21-Hydroxy-20-methylpregna-1,4-dien-3-one
Authors: Nitta Issei , Haruyama Toshio , Fujimori Shinichiro , Inoue Shinya , Ueno Hiroaki
Published: July 2006

17α,21-Dihydroxypregna-1,4-diene-3,20- dione, a potentially useful intermediate of prednisolone, can be prepared from 21-hydroxy-20-methylpregna-1,4-dien-3-one, a biodegradation product of cholesterol.
Nonadiabatic Transitions in Photochemical Electrocydic Reaction of Acrylaldehyde to Form 2H-Oxete
Authors: Morihashi Kenji , Kubota Hiroshi , Kikuchi Osamu
Published: July 2006

The photochemical electrocyclic reaction of s-cis-acrylaldehyde to form 2H-oxete was examined on the basis of the nonadiabatic interaction between potential energy surfaces. The nonadiabatic coupling g terms were calculated by the reduced classical-trajectory method along two postulated reaction paths, the concerted path and the step-by-step path. The calculated g terms were characteristic of the avoided crossing between the potential energy surfaces. The calculated g terms and the transition probabilities indicated that the step-by-step path was very efficient in the formation of 2H-oxete from the π–π* state of acrylaldehyde.
The Photochemical Magnetic Field Effect of Isoquinoline N-Oxides
Authors: Hata Norisuke
Published: July 2006

The irradiation of isoquinoline N-oxide in ethanol resulted in the formation of lactam in a ca. 67% yield via the S1 state (Process I). When the photochemical isomerization was carried out in the presence of a magnetic field, the chemical yield of lactam was found to show a minimum at approximately 1T. In order to interpret this new phenomenon, Process I was assumed to be initiated by electron transfer from the excited singlet N-oxide to the hydrogen-bonded ethanol (the formation of a singlet hydrogen-bonded radical ion pair). Thus, the new type of magnetic-field effect was excellently explained in terms of an electron-nuclear hyperfine interaction mechanism including the electron-exchange interaction in the radical-ion pair (the magnetic-field effect due to HFI-J mechanism). This implies that the magnetic-field effect is unambiguous evidence that Process I (N-oxide→lactam) does not involve the oxaziridine intermediate, but proceeds via the singlet hydrogen-bonded radical-ion pair (radical-ion-pair mechanism of Process I). The irradiation of 1-cyanoisoquinoline N-oxide in ethanol resulted in the formation of 1,3-oxazepine in a ca. 66% yield via the S1 state(Process II). The photochemical isomerization was not affected at all by an external magnetic field. This is consistent with the idea that Process II (N-oxide→oxazepine) does not involve a field-sensitive intermediate, but occurs with the intervention of oxaziridine (the oxaziridine mechanism of Process II).
Rate and Mechanism of Ligand Exchange of Several Tris(β-diketonato)iron(III) Complexes with 4-Isopropyltropolone in Carbon Tetrachloride
Authors: Sekine Tatsuya , Inaba Kazuho
Published: July 2006

The rate of ligand exchange of seven tris(β-diketonato)iron(III) in carbon tetrachloride with 4-isopropyltropolone was measured by a spectrometric method in order to determine the effect of the chemical properties of the leaving ligand on the reaction mechanism. It was found from the dependence of the rate on the leaving and entering ligands and also from the values of ΔH\eweq and ΔS\eweq that the exchange reaction of iron(III) complexes with acetylacetone and its two phenyl-substituted derivatives proceeds by a dissociative mechanism. It was also found that reactions with trifluoroacetylacetone and its phenyl- and 2-thienyl-substituted derivatives proceeds by an associative mechanism. An hexafluoroacetylacetonato complex formed an intermediate with the entering ligand in the first stage of the reaction and then a ligand exchange occured. It was concluded from these results that the ligand exchanges of more stable complexes were controlled by the break of a leaving ligand. Less stable ones were controlled by bond formation with the entering ligand.
Inclusion Complex Formation of γ-Cyclodextrin. One Host-Two Guest Complexation with Water-soluble Dyes in Ground State
Authors: Hirai Hidefumi , Toshima Naoki , Uenoyama Satoshi
Published: July 2006

β-Cyclodextrin forms the 1:1 inclusion complex with Crystal Violet, Methylene Blue, Methyl Orange, or Congo Red in water. On the other hand, γ-cyclodextrin forms the 1:2 complex with Crystal Violet, Methylene Blue, or Methyl Orange, while the 1:1 complex is given with Congo Red. The one host-two guest complexations are shown on the bases of the changes of the electronic spectra, dependence of induced circular dichroisms on the concentrations of dyes, and the continuous variation methods with induced circular dichroism. The dissociation constants for the 1:2 complexes are determined with the improved Benesi-Hildebrand equation. Alternation between the 1:1 and 1:2 complexation is discussed in terms of the cavity size of cyclodextrin and the aggregation character of dye.
Multiple Substituent Effects on 13C Chemical Shifts of N-Benzylideneanilines. Evidence for Substituent–Substituent Interactions and Their Implications of Conformational Changes with Substituents
Authors: Akaba Ryoichi , Sakuragi Hirochika , Tokumaru Katsumi
Published: July 2006

Carbon-13 chemical shifts are reported for series of N-benzylideneanilines; 4-YC6H4CH=NC6H4NMe2-4, 4-NO2C6H4CH=NC6H4X-4, 4-YC6H4CH=NC6H4NO2-4, and 4-YC6H4CH=NC6H3(CH3)2-2,6. Multiple substituent effects on the azomethine carbon chemical shifts were examined, and nonadditivity observed for 4-YC6H4CH=NC6H4NMe2-4 and 4-NO2C6H4CH=NC6H4X-4 is interpreted in terms of substituent–substituent interactions accompanied by conformational changes with substituents in these N-benzylideneanilines. Effects of the substituents Y (on the benzylidene benzene ring) on the azomethine carbon chemical shifts were also studied in detail. The results suggest that there are two competetive electronic factors responsible for chemical shift variation, and that the substituent effects should be treated separately between electron-releasing and electron-withdrawing groups. The latter groups always exert inverse (the chemical shifts undergo upfield shifts with increase in the electron-withdrawing properties of the substituents) substituent effects, whereas the former exhibit normal (the chemical shifts undergo upfield shifts with increase in the electron-releasing properties of the substituents) or inverse substituent effects depending on the degree of electron demand developed on the azomethine carbons.
Synthesis of 3-Amino-5H-pyrido[4,3-b]indoles, Carcinogenic γ-Carbolines
Authors: Akimoto Hiroshi , Kawai Akiyoshi , Nomura Hiroaki
Published: July 2006

The carcinogenic γ-carbolines 3-amino-1,4-dimethyl-5H-pyrido[4,3-b]indole (1) and 3-amino-1-methyl-5H-pyrido[4,3-b]indole (2) were synthesized efficiently by the following procedures. The key method involved the acid-catalyzed cyclization of 2-acetamido-3-(2-indolyl)alkanoic acids to 1,2-dihydro-γ-carbolines. This was followed by dehydrogenation to the γ-carbolinecarboxylates and conversion of the ester group to the carboxyl and finally to the amino one by Curtius rearrangement. Alternative methods involved the thermolysis of 4-(1-benzotriazolyl)-3,6-dimethyl-2-pyridinamine to synthesize 1 and the condensation of 3-acetylindole-2- acetonitrile with ammonia to synthesize 2. The structures of γ-carbolines 1 and 2 were unambiguously established by comparing samples of each synthesized by the two different routes. A selective and one-step synthesis of ethyl 2-acetamido-3-(2-indolyl)alkanoates was newly exploited starting from diethyl acetamidomalonate and quaternary ammonium salts of 2-[1-(dimethylamino)alkyl]indoles.
A Conductance Study of Benzo-18-crown-6- and Its Analogs-Alkali Metal Ion Complexes in Various Solvents
Authors: Takeda Yasuyuki
Published: July 2006

Limiting ionic molar conductivities of benzo-18-crown-6 (B18C6)–alkali metal ion complexes in various nonaqueous solvents were determined at 25 °C. The mobilities of the B18C6 complexes were compared with those of 18-crown-6 (18C6)– and dibenzo-18-crown-6 (DB18C6)–alkali metal ion complexes. Regardless of varieties of alkali metal ions held in the crown ether cavity, the larger is the size of the crown ether complex, the less mobile the complex is. For aprotic solvents (acetonitrile, DMF, DMSO, propylene carbonate), the mobility of the B18C6–K+ complex is smaller than that of (n-C4H9)4N+; however, for the protic solvent (methanol), they are almost the same. Walden product value of the B18C6–K+ complex as well as 18C6– and DB18C6–K+ complexes somewhat changes with the variation of solvents. For these three crown ether–K+ complexes, Walden product values of acetonitrile and propylene carbonate are larger than or nearly equal to those of DMF and DMSO. This may indicate that, for the aprotic solvents, donicity is a very important factor in determining the magnitude of mobility of the crown ether–K+ complexes. The B18C6–K+ complex as well as 18C6- and DB18C6–K+ complexes seems to act as a structure breaker in a hydrogen-bonding solvent.
The Crystal and Molecular Structure of Tetrakisthiocyanatobis-(triphenylphosphine)cobalt(II)mercury(II) in Dimer Form, [CoHg(SCN)4{(C6H5)3P}2]2
Authors: Kinoshita Hisashi , Shimoi Mamoru , Ouchi Akira
Published: July 2006

The crystal and molecular structure of the title metal complex was determined by the X-ray diffraction method. The crystal is triclinic, with the space group P\bar1, Z=1, a=11.934(2), b=14.642(9), c=11.801(6)Å, α=90.41(5), β=94.04(2), and γ=83.82(2)°. The final R value for 6928 reflections is 0.065. The cobalt(II) ato is in a tetrahedral geometry, ligated by four nitrogen atoms of the thiocyanato (SCN) ligands, while the mercury(II) atom is in a trigonal-bipyramidal geometry, where two phosphorus atoms of both the triphenylphosphine ligands bond axially and three sulfur atoms of SCN’s equatorially; however, these Hg–S bonds are very long. Thus, the pairs of cobalt(II) and mercury(II) atoms are linked by one SCN bridge, forming a sixteen-membered ring of Co2Hg2(SCN)4, and this ring is linked with the next ones on both sides in the a-axis direction with two longer bondings.
Hydrogenation of Carbon Monoxide to Form Light Olefins over an Iron-modified Crystalline Silica
Authors: Sano Tsuneji , Yanagisawa Hiroshi , Okabe Kiyomi , Okado Hideo , Hagiwara Hiroyuki , Yasumoto Yoshiroh , Takaya Haruo
Published: July 2006

Iron-modified crystalline silicas prepared from an Fe(II) compound were more active than those prepared from an Fe(III) compound. The (C2H4+C3H6) selectivity of the former was lower than that of the latter. By the addition of alkaline earth metals, the (C2H4+C3H6) selectivity of the catalysts prepared from the Fe(II) compound increased remarkably.
Change of Orientation in Photoreaction by Oxygen. Effect of Oxygen on Photo-methoxylation of Dimethyl Esters of 2,4- and 3,4-Pyridinedicarboxylic Acid
Authors: Sugiyama Toru , Kanai Mitsuharu , Takenaka Setsuko , Sugimori Akira
Published: July 2006

The UV-irradiation of dimethyl 2,4- and 3,4-pyridinedicarboxylates in methanol in the presence of H2SO4 under O2 brings about methoxylation at the β- position of the pyridine ring, while under N2 methoxylation occurs at the α-position.
Crowned Tetrathiafulvalene Derivatives
Authors: Otsubo Tetsuo , Ogura Fumio
Published: July 2006

A new type of tetrathiafulvalene derivatives, fused with crown ethers, was prepared, which did not form a complex with sodium cation or TCNQ acceptor but readily with silver cation.
Preparation and Characterization of Some Co(III) Complexes Containing (1R,2R)-Dimethyl-1,2-cyclohexanediamine. Crystal Structure of (+)435-trans-[CoCl2(R,R-dmchxn)2]Cl·HCl·2H2O
Authors: Sato Mitsunobu , Yokoo Yasuhiko , Yashiro Morio , Yano Shigenobu , Yoshikawa Sadao , Kobayashi Kimiko , Sakurai Tosio
Published: July 2006

(−)546-trans-[Co(NO2)2(R,R-dmchxn)2]+ and (+)546-Λ-Co(CO3)(R,R-dmchxn)2]+, which had been newly prepared, reacted with concentrated HCl to give, respectively, (−)435-trans-(SSSS)-[CoCl2(R,R-dmchxn)2]+ and (+)435-trans-(SRRS)-[CoCl2(R,R-dmchxn)2]+ stereospecifically, where R,R-dmchxn=(1R,2R)-N,N′-dimethyl-1,2-cyclohexanediamine. The stereospecific formation of (+)546-Λ-[Co(CO3)(R,R-dmchxn)2]+ has been observed. The trans-dichloro complexes and their precursors have been characterized by elemental analysis and by electronic absorption, circular dichroism, 1H NMR, and 13C NMR spectroscopies. An X-ray crystal-structure determination was undertaken on one of the trans-dichloro isomers, (+)435-[CoCl2(R,R-dmchxn)2]Cl·HCl·2H2O, whose structure could not be characterized by usual spectroscopies. This complex forms triclinic crystals with a=11.395(10) Å, b=11.674(8) Å, c=11.031(8) Å, α=98.62(6)°, β=102.48(8)°, γ=118.24(5)°, and Z=2, in the space group P1. Least-squares refinements converged at an R value of 0.041 for 4870 independent reflections with Fo>3[σ(Fo)]. The complex cation has an approximately twofold symmetry. The conformations of the two five-membered chelate rings are both λ. The arrangements of the groups around the two secondary nitrogen atoms are R and S in each diamine. The isomerization from the (+)435-trans-dichloro complex to the (−)435 isomer has been observed under mild basic conditions.
Oxidative Removal of N-(4-Methoxybenzyl) Group on 2,5-Piperazinediones with Cerium(IV) Diammonium Nitrate
Authors: Yamaura Masanori , Suzuki Tsuneji , Hashimoto Hironobu , Yoshimura Juji , Okamoto Thoru , Shin Chung-gi
Published: July 2006

It was shown that N-(4-methoxybenzyl) group on 2,5-piperazinediones can be oxidatively removed with cerium(IV) diammonium nitrate under mild conditions, and the oxidative removal was performed in some model compounds which have several functional groups.
The α-Chlorination of Aryl Ketones with Manganese(III) Acetate in the Presence of Chloride Ion
Authors: Tsuruta Takehiko , Harada Tetsuya , Nishino Hiroshi , Kurosawa Kazu
Published: July 2006

The reaction of 2-(4-methoxyphenyl)-4-chromanone with Mn(OAc)3 in the presence of LiCl gave 3,3-dichloro-2-(4-methoxyphenyl)-4-chromanone. The reactions of 2-phenyl-4-chromanone, 1-phenyl-1-propanone, 1,2-diphenylethanone, and 1-tetralone similarly yielded α,α-dichloro derivatives in good yields. 2,2,2-Trichloroacetophenones were obtained from 2,2-dichloroacetophenones, but in the absence of LiCl, 2,2-dichloroacetophenones gave 2,2,3,3-tetrachloro-1,4-butanediones. KCl, NaCl, NH4Cl, AlCl3, and CaCl2 were also employed as the Cl− ion source. Synthetic applicability and the reaction mechanisms are discussed briefly.
Pentoside Synthesis by Dehydrative Glycosylation. Synthesis of O-α-l-Arabinofuranosyl-(1→3)-O-β-d-xylopyranosyl-(1→4)-d-xylopyranose
Authors: Koto Shinkiti , Morishima Naohiko , Takenaka Kazuhiro , Uchida Chisa , Zen Shonosuke
Published: July 2006

O-α-l-Arabinofuranosyl-(1→3)-O-β-d-xylopyranosyl-(1→4)-d-xylopyranose isolated from the hydrolyzate of corncobs arabinoxylan was synthesized by way of dehydrative glycosylation.
Brillouin Scattering of Supercooled Liquids. I. Tri-o-tolyl Phosphate
Authors: Koda Shinobu , Nomura Hiroyasu , Nakamura Masayuki , Miyahara Yutaka
Published: July 2006

The sound velocities of tri-o-tolyl phosphate in the GHz region were measured by means of the Brillouin scattering method over a wide range of temperatures. In the temperature range from 283 to 313 K, the sound velocity dispersion was observed directly. The relaxation curves of the longitudinal modulus could be analyzed using a B.E.L. model with a parameter of K=0.5. With a rising temperature, a deviation from the B.E.L. model appeared. We considered that the deviation was attributed to the rotational molecular motion of tri-o-tolyl phosphate.
Effects of Addition of Vanadium to Alumina-supported Ruthenium Catalyst on Adsorption and Hydrogenation of Carbon Monoxide
Authors: Enomoto Toshiyuki , Okuhara Toshio , Misono Makoto
Published: July 2006

The hydrogenation of carbon monoxide to hydrocarbons (Fischer-Tropsch synthesis) was studied over RU/Al2O3 catalysts to which transition metals such as V, Cr, Mn, and Ag were added. Among these additives, V was most effective for the suppression of methane formation, without changing the olefin/paraffin ratio and the propagation probability. The catalytic activity decreased and the infrared band of adsorbed carbon monoxide shifted only slightly upon the V addition, showing little change in the electronic state of Ru. The particle size of the Ru remained almost unchanged, although the degree of hydrogen adsorption decreased to half. This indicates that Ru particles were partially covered by V (or an oxide of V). The effect on the turnover frequency of hydrogenation of CO was compared with those for the hydrogenation of benzene, and the hydrogenolysis of ethane. These effects were found to be very similar to an ensemble effect reported for Ru–Cu/SiO2 catalysts. On the basis of these results, it is concluded that the addition of V brought about an effect similar to the ensemble effect.
Hexacarbonylmolybdenum-induced Reaction of Isoxazoles. Cycloaddition of Isoxazoles with Acetylenic Esters and Related Reactions
Authors: Kobayashi Tomoshige , Nitta Makoto
Published: July 2006

In the presence of hexacarbonylmolybdenum, substituted isoxazoles undergo a cycloaddition reaction with dimethyl acetylenedicarboxylate across the C-4–C-5 bond to give 3,4-bis(methoxycarbonyl)pyridine derivatives. In a similar cycloadition of isoxazoles with methyl propiolate, 4-(methoxycarbonyl)pyridine derivatives were also obtained. The β-carbon atom of methyl propiolate could intervene in the bonding with the C-5 position of the isoxazoles regioselectively. A mechanism involving a complexed 2-oxa-3-azabicyclo[3.2.0]hepta-3,6-diene derivative and the subsequent N–O and C-1–C-5 bond cleavage leading to a complexed (β-keto vinyl)nitrene intermediate is proposed for the formation of pyridine derivatives. In order to clarify the mechanistic aspect, the reaction of 4-phenyl-2-oxa-3-azabicyclo[3.2.0]hepta-3,6-diene and its related compounds were also studied to give pyridine derivatives.
The Co-amination of Phenol and Cyclohexanol with Palladium-on-carbon Catalyst in the Liquid Phase. An Application of a Hydrogen-transfer Reaction
Authors: Hamada Hideaki , Yamamoto Makoto , Kuwahara Yasushi , Matsuzaki Takehiko , Wakabayashi Katsuhiko
Published: July 2006

Phenol and Cyclohexanol are simultaneously aminated to aniline and cyclohexylamine by ammonolysis with the palladium-on-carbon catalyst in the liquid phase, although the amination of either phenol or cyclohexanol hardly occurs without the other. In contrast, carbon-supported ruthenium, rhodium, and platinum catalysts are ineffective for this co-amination; they are active only for the amination of cyclohexanol to cyclohexylamine. These results are explained by the specific activity of palladium for hydrogen transfer between phenol and cyclohexanol.
Selective Hydrogenation of Conjugated Dienes Catalyzed by Thiocyanatotris(triphenylphosphine)cobalt(I)
Authors: Nakayama Taisei , Kanai Hiroyoshi
Published: July 2006

Thiocyanatotris(triphenylphosphine)cobalt(I) prepared in situ from bis(thiocyanato)bis(triphenylphosphine)cobalt(II), triphenylphosphine, zinc bromide, selectively hydrogenated conjugated dienes to the corresponding cis-monomenes. The C2-or/and C3-methyl substituted 1,3-butadienes enhance the reactivity by a factor of 2.3 per one methyl group, while C1- or/and C4-methyl substituted 1,3-butadienes lower the reactivity by a factor of 1/23 per one methyl group. In the hydrogenation of cyclic conjugated dienes α-angle (∠C–C=C) is closely related to the hydrogenation rate. The rates of hydrogenation in cyclic ethers are greater than those in acyclic ethers, but the cis-selectivity in acyclic ethers is much higher. Deuterium selectively adds to 1,3-butadiene and 2,5-norbornadiene (bicyclo[2.2.1]hepta-2,5-diene) to give 3,4-dideuterio-1-butene and cis-1,4-dideuterio-2-butene, and endo,endo-5,6-dideuterionorbornene and endo,endo-3,5-dideuterionortricyclene, respectively. A mechanism is proposed which derives from anti-π-allylcobalt hydride or delocalized nortricyclenylcobalt hydride as an intermediate.
Syntheses of Diferrocenyl Trithiocarbonate and a Tetrathio-substituted Ethylene Derivatives of Ferrocene
Authors: Sato Masaru , Akabori Sadatoshi
Published: July 2006

Diferrocenyl trithiocarbonate, 1,3-dithia[3]ferrocenophane-2-thione, and 2,2′-bi(1,3-dithia[3]-ferrocenophan-2-ylidene) were prepared.
Effects of Uniaxial Pressure and Shear on the Electrical Conductivity of Solid. II. Electrical Conductivity in Some Amorphous Coordination Polymers
Authors: Kanda Seiichi , Ohkawa Kuwako , Yamashita Kenichi , Oda Nobuo , Chihara Hideaki
Published: July 2006

Three amorphous coordination polymers, R2dtoaCu, where R=CH3, C6H5CH2, or cyclohexyl and dtoa=(N,N′-disubstituted dithiooxamidato), were prepared and the effect of uniaxial pressure on their electrical resistivities in the direction of the external pressure was measured. Application of the pressure up to 6×108 Pa caused an increase in the resistivity but, before reaching the equilibrium state, the resistivity exhibited a complicated time variation, which was not completely reversible upon pressure release as far as the measurement could trace. The results were explained on the basis of a model in which at least two competing processes occur. One of the processes is assumed to be reorientation of the two-dimensional network of molecules perpendicular to the applied pressure, which is a slow process and takes as long as hundreds of hours to reach the equilibrium. Activation energies of various processes were derived.
Tetraalkylammonium Ion-selective Electrodes with Supporting Electrolytes. An Experimental Test of the Theory of Liquid Ion-exchange Membrane Ion-selective Electrodes Based on the Concept of the Mixed Ion-transfer Potential
Authors: Kakiuchi Takashi , Obi Ichiro , Senda Mitsugi
Published: July 2006

Selectivity characteristics of liquid-membrane ion-selective electrodes for tetraethylammonium and triethylmethylammonium ion-selective electrodes in the presence of homologous tetraalkylammonium ions as interfering ions were studied with supporting electrolytes both in the liquid membrane and in the sample solution. The emf vs. logarithm of the concentration of the primary ion curves in the presence of interfering ion were well described by the theory of liquid-membrane ion-selective electrodes which is based on the concept of the mixed ion-transfer potential at the liquid-membrane/sample solution interface. The dependence of the selectivity coefficients on the concentrations of the primary ion in the liquid membrane and of the interfering ion in the sample solution agreed well with the theoretical prediction.