bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mesomorphic Properties of 2-(4-n-Alkoxybenzylideneamino)anthracenes
Authors: Sakagami Sakumitsu , Nakamizo Minoru 
Published: July 2006

Abstract
2-(4-n-Alkoxybenzylideneamino)anthracenes were synthesized, and the phase transitions were determined using a differential scanning calorimeter and a polarizing microscope. Methoxy through propoxy derivatives exhibit the monotropic nematic state, whereas the higher members show the enantiotropic nematic state.
The Analytical Application of Oleophilic Quaternary Ammonium Salts. XI. The Extraction of the Iron(III)–Pyrocatechol Violet–Tridodecylethylammonium Ternary Complex
Authors: Shijo Yoshio 
Published: July 2006

Abstract
The ionic associate of the iron(III)–Pyrocatechol Violet chelate anion with tridodecylethylammonium bromide is extracted into methyl isobutyl ketone. The ternary complex has an absorption maximum at 623 nm. The optimum pH for the extraction is 5.7–6.4 The molar absorptivity of the complex is 7.76×104 cm−1·mol−1·l. Its composition is estimated to be (Remark: Graphics omitted.).
Solvent Extraction Equilibria of Acids. V. The Extraction of Hydrobromic, Hydroiodic, and Thiocyanic Acids with Trioctylphosphine Oxide in Hexane
Authors: Niitsu Masaru , Sekine Tatsuya 
Published: July 2006

Abstract
The solvent extraction of hydrohalogenic acids and thiocyanic acid (HX) in 1 mol dm−3 electrolyte solutions with trioctylphosphine oxide (E) has been studied at 25 °C. The extraction constant, Kex1=[HXE]org[H+]−1[X−]−1][E]org−1, for thiocyanic acid was found to be 102.5, while Kex2=[HXE2]org[H+]−1[X−]−1[E]org−2 for hydrobromic and hydroiodic acids were found to be 100.34 and 101.78 respectively.
Condensation Products of Benzanthrone Obtained Using Copper Powder and Fused Zinc Chloride
Authors: Aoki Junji , Takekawa Minoru , Fujisawa Shoji , Iwashima Satoshi 
Published: July 2006

Abstract
By heating benzanthrone (3) with copper powder, zinc chloride, and sodium chloride, violanthrene B (8) and isoviolanthrene B (13) were obtained in addition to the tetrabenzo[a, cd, j, lm]perylene (4) reported previously. This method may be considered to be a convenient method of synthesizing not only 4, but also 13.
Vibration Spectra and Rotational Isomerism of Chain Molecules. II. Butane, Pentane, Hexane, Pentane-d12, and Hexane-d14
Authors: Harada Issei , Takeuchi Hideo , Sakakibara Masaaki , Matsuura Hiroatsu , Shimanouchi Takehiko 
Published: July 2006

Abstract
The Raman spectra of butane, pentane, hexane, pentane-d12, and hexane-d14 and infrared spectra of pentane-d12 and hexane-d14 were measured for the liquid and solid states. The rotational isomerism of normal paraffins was studied on the basis of the spectral observations and the normal coordinate calculations. The spectra of the deuterated compounds were useful in the confirmation of the less stable isomers and the establishment of the local symmetry force field of normal paraffins. The enthalpy differences among the rotational isomers were studied on pentane and hexane, which yielded some important data for the study of the conformations and properties of longer hydrocarbons.
Statistical Mechanical Calculation of the Radial Distribution Function for a Water-like Fluid
Authors: Hirata Fumio 
Published: July 2006

Abstract
The radial distribution function (RDF) for a water-like system, which has the fundamental characteristics of water, is calculated using the graph-theoretical technique developed by Andersen and Chandler. An interaction potential devised to simulate the hydrogen bond is regarded as a perturbation of the pair interaction between the two molecules of a reference system which consists of hard spheres each having a point dipole at each center. The effect of the hydrogen bond-like potential on the distribution of the molecules is shown explicitly. The results show a tetrahedral coordination similar to that in water. The resulting RDF has qualitatively reproduced the features observed in the experimental RDF curve for water.
Violet Emission Bands of the CN Radical Produced by Photodissociation of BrCN
Authors: Tatematsu Setsuko , Kondow Tamotsu , Nakagawa Toru , Kuchitsu Kozo 
Published: July 2006

Abstract
The violet emission spectra of CN(B2∑−X2∑), Δv=0, were observed by the photodissociation of BrCN by Lyman-α radiation (121.6 nm). The peak intensities for the vibrational levels v′≥1 relative to v′=0 decreased with the BrCN pressure (up to 2 Torr), whereas at 0.1 Torr or lower the spectrum was essentially independent of the pressure. The relative vibrational populations (v′=0–10) and the effective rotational temperatures were estimated by a band-envelope analysis. The effective rotational temperature, estimated to be 2000±200 K for v′=0–4, was practically independent of the pressure. Within the low-pressure limit the distributions of the excess energy to vibration and rotation were estimated to be 0.50±0.08 and 0.17±0.02 eV, respectively.
2-Mercaptobenzothiazole Supported on Silica Gel for the Chromatographic Concentration of Cadmium, Copper, Lead, and Zinc in Natural Water Samples
Authors: Terada Kikuo , Inoue Akihiko , Inamura Junko , Kiba Toshiyasu 
Published: July 2006

Abstract
The preparation and characteristics of 2-mercaptobenzothiazole supported on silica gel (MBT–SG), and its application to the preconcentration and determination of cadmium, copper, lead, and zinc in natural water samples are described. The MBT–SG was prepared by impregnating silica gel with MBT in a dioxane–methyl acetate solvent mixture, drying, washing with deionized water, and finally drying. The chelating capacity of the material was 0.01 meq. Cu/g. Cadmium, copper, lead, and zinc were quantitatively retained on the MBT–SG at pH values of 4.8, 2.5, 4.8, and 6.5 for an aqueous solution, and at pH values of 4.8, 2.8, 4.8, and 6.5 for sea water. A column made of the material provided quantitative recovery of these metals from natural water samples at higher flow rates (2–5 1/h) than other chelating resins, e. g., chelex 100. Cadmium was eluted with hydrochloric acid (1 : 99), copper and lead with acetone–hydrochloric acid mixture (9 : 1), and zinc with an acetate–hydrochloric acid buffer solution (pH 4.0). Then, the quantities of the four metals in their effluents were determined by atomic absorption spectrometry.
The Transannular Cyclization and Hydrogen Shift in the Chlorination of 1,5-Cyclooctadiene and cis-Cyclooctene with Antimony(V) Chloride
Authors: Uemura Sakae , Onoe Akira , Okano Masaya 
Published: July 2006

Abstract
The slow addition of SbCl5 to a CCl4 solution of 1,5-cyclooctadiene or cis-cyclooctene gives an isomeric mixture of endo- and exo-2, anti-8-dichlorobicyclo[3.2.1]octanes (1 and 2) or an isomeric mixture of trans- and cis-1,4-dichlorocyclooctanes (12 and 13) respectively in a good yield. The former reaction involves the transannular cyclization, while the latter is accompanied by the transannular hydrogen shift. The addition of 1,5-cyclooctadiene to a CCl4 solution of SbCl5 (reverse addition) affords endo-2,6- and endo, exo-2,6-dichlorobicyclo[3.3.0]octanes (6 and 7) as additional products, besides 1 and 2. In the case of cis-cyclooctene, however, a reverse addition produces only chlorocyclooctane. It has been revealed that a mixture of 6 and 7 is readily isomerized to a mixture of 1 and 2 by the interaction with SbCl5. The 1,4-chlorination of cis-cyclooctene which gives 12 and 13 also occurs with VCl4, SeCl4, PhICl2, and PCl5, although the selectivity and the yield are low compared to the case of SbCl5.
Thermal Stability of Alkylcopper(I) Complexes Coordinated with Tertiary Phosphines
Authors: Miyashita Akira , Yamamoto Takakazu , Yamamoto Akio 
Published: July 2006

Abstract
Thermolysis of isolated alkylcopper(I) complexes having tertiary phosphine ligand(s) RCuLn (R=CH3, C2H5, n-C3H7, i-C4H9) in the solid state and in toluene has been studied in order to clarify the role of the tertiary phosphine ligand in stabilizing the alkylcopper(I) complexes. The distribution of the thermolysis products shows that the thermolysis of the alkylcopper complexes having ethyl or longer alkyl chain proceeds through a β-elimination mechanism. The rate of the thermolysis obeys the first order rate law, −d[RCuLn]/dt=k[RCuLn]. The activation parameters of the thermolysis were obtained from the temperature dependence of k and a compensation effect between ΔH\eweq and ΔS\eweq was demonstrated. The activation energy Ea of the thermolysis of RCu(PPh3)2 increases in the order of R=C2H5&lt;n-C3H7&lt;i-C4H9. Coordination of electron-donating tertiary phosphine decreases Ea and a linear relationship between ν(Cu–CH3) frequencies and Ea for thermolysis of the methylcopper complexes was observed. Addition of PPh3 into the toluene solutions of CH3Cu(PPh3)2(diethyl ether)0.5 and C2H5Cu(PPh3)2 causes some retardation of the thermolysis. The major role of the tertiary phosphine ligand in stabilizing the alkylcopper complexes is proposed to strengthen the Cu–C bond by changing the electronic state of copper atom. An energetic consideration based on Chatt and Shaw’s theory is given in order to account for the results concerning the stabilities of the alkylcopper complexes. Photolysis of the alkylcopper complexes takes a quite different decomposition pathway producing mainly RH from RCuLn.
Enzyme-like Reaction Catalyzed by NAD+–Reduced Keratin Systems
Authors: Hirano Morio , Takahashi Fujio 
Published: July 2006

Abstract
Reduced keratin, which was obtained by reductive cleavage of human hair, was found to form a 1 : 1 complex with nicotinamide adenine dinucleotide (NAD+). The complex exhibited catalytic activity for the oxidation of glyceraldehyde to form glyceric acid. It was found from the results of pH titration, polarograms and NMR measurements that the NAD+-reduced keratin complex binds to glyceraldehyde to form an intermediate, which is susceptible to oxidation by oxygen. It was concluded from kinetic studies that this catalytic reaction showed a homotropic effect.
Photochemical Reactions of 4-Flavanols in the Presence of Ketone Sensitizers
Authors: Suzuki Morio , Amano Jiro , Morioka Motonobu , Mizuno Hideo , Matsushima Ryoka 
Published: July 2006

Abstract
Irradiation of an oxygen-free benzene solution of cis-4-flavanol 1a by a mercury lamp in the presence of benzophenone gave 4-flavanone (32%), benzopinacol (85%), cis- and trans-2-(diphenylhydroxymethyl)-4-flavanols (7.6%), and 2-(diphenylhydroxymethyl)-4-flavanone (7.7%), whereas photolysis of cis-4-acetoxyflavane under similar conditions gave cis-2-(diphenylhydroxymethyl)-4-acetoxyflavane(24%), 2,2′-bi-4-acetoxyflavane (6%), and benzopinacol. Photolysis of 1a in acetone gave 4-flavanone (3.6%), trans-4-(1-hydroxy-1-methylethyl)-4-flavanols (9.9%). The cis isomers of the parent and substituted 4-flavanols showed higher reactivities than the corresponding trans isomers.
Sequential Polypeptides. The Steric Hindrance of l-Valine Residues in the Polycondensation of Peptide Active Esters
Authors: Katakai Ryoichi 
Published: July 2006

Abstract
Five tripeptide N-hydroxysuccinimide esters with N-terminal l-valine, l-phenylalanine, and l-alanine were polymerized in N,N-dimethylformamide with a variety of concentration of the monomers. The yields and molecular weights of the resulting sequential polypeptides were then compared in order to demonstrate the presence of the steric hindrance of the l-valine residue in polycondensation. The results of the polycondensation and the conformational study of the resulting polypeptides suggest that the side chain of the l-valine residue at the N-terminal position of the monomers hinders the polycondensation of the monomers.
The Reactions of Aryldiazomethanes with Sulfur Dioxide in the Presence of Enamines
Authors: Tanabe Toyoshige , Nagai Toshikazu 
Published: July 2006

Abstract
The reactions of several arydiazomethanes with sulfur dioxide in the presence of 2-methyl-1-morpholinopropene gave cyclic sulfones, thietane 1,1-dioxides, indicating the existence of sulfene as a reaction intermediate. The stereoselectivity of the sulfene-enamine cycloaddition showed that the less thermodynamically stable cis orientation was generally preferred. On the other hand, the reactions in the presence of 1-morpholinocyclohexene, which has a labile proton β to the morpholino moiety, afforded acyclic or cyclic sulfones, depending on the substituents of diazomethanes. The mechanism of these reactions is discussed.
Gas Chromatographic Studies of the Thermal Decompositions of Hexaammine-, Chloropentaammine-, and trans-Dichlorotetraammine-cobalt(III) Chloride in the Solid State
Authors: Onodera Sukeo 
Published: July 2006

Abstract
This paper will describe gas chromatographic studies of the thermal decomposition of cobalt(III) ammine complexes in the solid state. The sample is pyrolyzed in a chamber in a helium atmosphere at a heating rate of 1 °C/min. The evolved products are directly led into a chromatographic separation column at periodic intervals of 10 °C. The preliminary gaseous product for these compound is ammonia. The gas evolution(GE) curves for each compound could be made as function of the temperature on the basis of the various gas chromatograms. These GE curves show two maximum peaks; the first is a sharp peak at about 250 °C, while the second is a broad peak in the 280–340 °C temperature range. The combination of these GE curves with the results of TG and DTA studies allows more complete interpretations of the thermal-decomposition reactions of the cobalt(III) ammine complexes.
Studies of the Isomerization of Unsaturated Carboxylic Acids. III. Thermal Rearrangement of Dimethyl Methylenesuccinate to Dimethyl Mesaconate
Authors: Sakai Mutsuji 
Published: July 2006

Abstract
Dimethyl methylenesuccinate (1) was found to equilibrate with dimethyl mesaconate (3) at elevated temperatures. Thermal rearrangements of 1 and 3 were studied kinetically and a plausible mechanism is proposed.
ESR Study on the Photoreduction of N-Acetyldiphenylmethyleneamine in 2-Propanol
Authors: Toshima Naoki , Aoki Kyoji , Hirai Hidefumi 
Published: July 2006

Abstract
Photoreduction of N-Acetyldiphenylmethyleneamine (1) in 2-propanol was studied both by the ESR spectroscopy of irradiated imine 1 in a matrix solvent at −196 °C and by the deuteration analysis of acetone formed from 2-propanol-d in the photoreduction process. The ESR spectrum consists of a broad singlet and a quartet. The latter is assigned to the CH3CH(OH)\dotCH2 radical, which can be produced by β-hydrogen abstraction by the excited imine 1 from 2-propanol, but not by the excited benzophenone. Formation of acetone-d on irradiation of 1 in 2-propanol-d suggests that the imine 1 in the excited state has a hydrogen abstracting character.
Dichroism and Configuration Analysis of 2-Ethylthio-1,3-Diazaazulene
Authors: Hiratsuka Hiroshi , Tanizaki Yoshie , Hoshi Toshihiko 
Published: July 2006

Abstract
Electronic absorption spectrum of 2-ethylthio-1,3-diazaazulene (ESDA) is investigated by means of dichroism analysis using the stretched PVA film. Seven π-π* bands and an allowed n-π* band are assigned. The experimental assignment of π-π* bands is in good agreement with the theoretical result using the PPP calculation. The effect of substituent groups on 1,3-diazaazulene (DA) is discussed by making use of a correlation diagram of SCF MO’s of ESDA, 2-ethoxy-1,3-diazaazulene (EODA), DA, and the substituent groups. Configuration analysis of wave functions for ESDA and EODA is carried out, and the substituent effects of the ethylthio and ethoxyl groups are compared. The result shows that the ethylthio group perturbs the electronic structure of DA more strongly than the ethoxyl group.
Vibrational Spectra and Normal Coordinate Calculations for Trimethyiarsine–Borane
Authors: Watari Fumio 
Published: July 2006

Abstract
Studies were carried out on the infrared spectra (33–4000 cm−1) of eight isotopic trimethylarsine–boranes, (CH3)3AsBH3, (CH3)3As10BH3, (CH3)3AsBD3, (CH3)3As10BD3, (CD3)3AsBH3, (CD3)3As10BH3, (CD3)3AsBD3, and (CD3)3As10BD3, in the solid state at low temperature, and on the Raman spectra (0–4000 cm−1) in the solid state and in solution of dichloromethane at room temperature. The spectra were interpreted on the basis of C3V molecular symmetry, complete assignments for all fundamentals except the internal torsion being made. Normal coordinate calculations were carried out utilizing a symmetry force field in order to confirm the assignments. One of the methyl rocks was found to be mixed with the borane rock, making the assignments of these frequencies complicated. The As–B and As–C force constants were found to have the values 1.849 and 3.087 mdyn/Å, respectively.
A New Spectrophotometric Method for the Determination of Some Reducible Compounds by the Reduction with Chromium(II) Ion
Authors: Terada Kikuo , Honnami Hiromi , Kiba Toshiyasu 
Published: July 2006

Abstract
A number of reducible compounds, such as nitrates, nitrites, nitro, nitroso, azoxy compounds, aldehydes, carbon tetrachloride, oximes, and chloramine T, can be determined by reducing them with chromium(II) ion prepared in an aqueous solution in a special vessel and measuring the absorbance of the resulting chromium(III) in the solution. In this reducing process, nitrate and nitrite are reduced to hydroxylamine quantitatively in hydrochloric acid at room temperature; carbon tetrachloride, nitrobenzene, and chloramine T each consume definite amounts of chromium(II) in an acidic medium at room temperature; propionaldehyde and azoxybenzene react with the reagent only in a basic solution; dimethylglyoxime and 1-nitroso-2-naphthol react only under heating at 80 °C in an basic medium. The absorbance of the resulting chromium(III) ion in the presence of the excess chromium(II) is found to obey Beer’s law at the wavelengths of 410–425 nm over the range of 4×10−3–8×10−2 mol/l of chromium(III). This concentration range corresponds to about 10−5–10−4 mol of the reducible compounds mentioned above. A rapid and precise method has been established with few disadvantages.
Kinetics of the Proton-Transfer Reaction of 4-(2,4-Dihydroxyphenylazo)nitrobenzene in Dioxane–Water Media
Authors: Yoshida Noboru , Fujimoto Masatoshi 
Published: July 2006

Abstract
Kinetics of proton-transfer reactions in 4 to 50%(v/v) dioxane–water media between hydroxide ion and 4-(2,4-dihydroxyphenylazo)nitrobenzene (Magneson; MAG) having a strong OH···N intramolecular hydrogen-bond are studied by means of the temperature-jump method. The forward and the backward rate constants kf and kr[H2O] for the reaction OH−+HA−\oversetkf\undersetkr\ightleftharpoonsH2O+A2− are evaluated to be in the range of 9.2×105–1.3×105 mol−1 dm3 s−1 and 5.5×103–1.8×103 s−1, respectively. The dependence of the kf and the acid dissociation constant Kac on the dioxane contents of the medium is interpreted on the basis of solute-solvent interactions.
An MO-Theoretical Study of the Electronic Structures of Formyloxyl and Acetoxyl Radicals
Authors: Kikuchi Osamu , Utsumi Kayoko , Suzuki Keizo 
Published: July 2006

Abstract
A semi-empirical NDDO MO method was applied to formyloxyl(HCOO) and acetoxyl(CH3COO) radicals in order to determine whether the ground-state electronic structure of the acyloxyl radical is of σ- or π-type. A σ-type state was found to be more stable than a π-type state over the entire range of values of the OCO angles of these radicals. This appears to be in agreement with the experimental facts which have been derived from the ESR spectra of several acyloxyl radicals.
ESR of F Center in HgI2·2HgS Darkened with Sunlight
Authors: Takei Kunio , Hagiwara Hitoshi , Tanaka Hiroshi 
Published: July 2006

Abstract
When yellow powders of HgI2·2HgS turn black in sunlight in a few seconds, the black powders show an ESR signal, whose intensity increases with the time of irradiation; its g-value is 2.0046±0.00028. The result of analysis shows that this signal is due to F centers, consisting of electrons captured by positive holes prepared at sites of S2− ions in the crystal.
Synthesis and X-Ray Structure of Triethylenetetramine-palladium(II) Complex
Authors: Hori Fumio , Matsumoto Keiji , Ooi Shun’ichiro , Kuroya Hisao 
Published: July 2006

Abstract
The triethylenetetraminepalladium(II) perchlorate and the potassium triethylenetetraminepalladium(II)tris-(hexafluorophosphate) were prepared; the X-ray structure analysis has been carried out for the latter compound. The crystal of [Pd(trien)](PF6)2·KPF6 is orthorhombic, with space group Pbca: a=21.645 (5), b=20.873 (5), c=9.541 (2) Å, and Z=8. The structure has been determined from X-ray diffractometer data and refined to R=0.091 (1166 reflections). The Pd atom has a planar coordination of 4N atoms disposed in a somewhat trapezoidal form. The complex cation has a pseudo symmetry plane which is perpendicular to the 4 N plane and bisects the H2N–Pd–NH2 angle. In the quadridentate triethylenetetramine ligand, each of the terminal H2N–CH2–CH2–NH– fragments forms a 5-membered chelate ring with the asymmetric envelope conformation, whereas the chelate ring formed by the middle –NH–CH2–CH2–NH– fragment has the symmetric envelope conformation. The electronic spectrum of [Pd(trien)]2+ is presented.
Metal-ion Complexation of Noncyclic Poly(oxyethylene) Derivatives. I. Solvent Extraction of Alkali and Alkaline Earth Metal Thiocyanates and Iodides
Authors: Yanagida Shozo , Takahashi Kazutomo , Okahara Mitsuo 
Published: July 2006

Abstract
The reaction of noncyclic poly(oxyethylene) derivatives with alkali and alkaline earth metal ions was investigated by means of the solvent extraction of their thiocyanates or iodides. Polyethylene glycols with more than 23 oxyethylene units showed a strong extracting power comparable to those of the crown ethers, and the power increased with the increasing number of oxyethylene units in them. Extraction studies using homogeneous poly(oxyethylene) monododecyl ethers revealed that more than 7 oxyethylene units were necessary to bind the potassium ion in the water phase and to transfer the complexed salt to the organic phase, and that the extracting ability of octa(oxyethylene) monododecyl ether was about one sixth of that of 18-crown-6. The monododecyl ether is fairly effective as a complexing agent for potassium picrate even below its critical micelle concentration; the stoichiometry of the extractable complex was found to be 0.8:1 with respect to the ether and the picrate. There was no remarkable difference in the selectivity for alkali metal ions between noncyclic poly (oxyethylene) derivatives and 18-crown-6.
Mechanism of the Reduction of Nitric Oxide with Ammonia over Cu(II) Ion-Exchanged Zeolites
Authors: Arakawa Tsuyoshi , Mizumoto Mamoru , Takita Yusaku , Yamazoe Noboru , Seiyama Tetsuro 
Published: July 2006

Abstract
The catalytic NO reduction with NH3 over Cu(II) ion-exchanged zeolite was studied with special attention to the temperature dependence of catalytic activity which reaches maximum at ca. 120 °C. ESR study showed that in the catalytic system all the exchanged copper ions exist as Cu(II) up to ca. 120 °C, above which Cu(II) ions decrease with a rise in temperature. The reaction rates measured at 110 and 140 °C were found to show similar dependence on both NO and NH3 partial pressures, indicating that the reaction mechanism does not differ much. By lowering temperature the Cu(I) ions formed at higher temperatures were reoxidized to Cu(II), accompanied by N2O formation due to the disproportionation of NO. From the results and the IR spectroscopic data a reaction mechanism was proposed. It includes a step in which NO reacts with NH3 adsorbed to Cu(II) ions to give rise to the evolution of N2 and the reduction of Cu(II) ions, and steps in which Cu(II) ions are regenerated accompanying the evolution of N2+N2O.