bluuebunny/crossref_metadata_2025_split huggingface dataset:
Heat Capacity of Potassium p-Chloranil Anion Radical Salt between 13 and 330 K
Authors: Kosaki Akio , Sorai Michio , Suga Hiroshi , Seki Syûzô 
Published: July 2006

Abstract
The heat capacity measurement for an organic free-radical salt, potassium p-chloranil, revealed a first-order phase transition at Tc=260.01 K. In spite of a first-order nature, the pre- and the post-transitional effects are remarkable. The enthalpy and the entropy of transition were determined to be ΔH=2796 J mol−1 and ΔS=11.06 JK−1 mol−1, respectively. The magnetic contribution to ΔS is only 2.23 JK−1 mol−1 when a dimeric configuration with a singlet-triplet spin equilibrium is assumed in the low temperature phase and a monomeric behavior of radicals with spin doublet is assumed above Tc. The present phase transition bears a close resemblance to a spin-Peierls transition in a linear chain system. The infrared spectrum at 120 K indicates a possible formation of dimers in the low temperature phase of this salt. A phenomenological model for the present phase transition is presented.
Acidic Properties of SiO2–MoO3 and MoO3, and Their Catalytic Activities
Authors: Maruyama Kazumasa , Hattori Hideshi , Tanabe Kozo 
Published: July 2006

Abstract
MoO3, SiO2, and SiO2–MoO3 of different compositions were prepared and their surface and catalytic properties examined. A large number of acid sites were generated by mixing SiO2 with MoO3, while each component oxide by itself did not exhibit any appreciable acidic properties. The oxidizing property of MoO3 was enhanced by mixing with SiO2. No new compounds were detected in the oxide mixture by X-ray diffraction. The activity for depolymerization of 2,4,6-trimethyl-1,3,5-trioxane correlated well with the surface acidity. In the isomerization of 1-butene, both MoO3 and SiO2–MoO3 were active. The active sites on MoO3 were poisoned by CO2 but not by NH3, while those on SiO2–MoO3 were poisoned by NH3 but not by CO2.
Crystal Field Levels of Neodymium and Erbium Ethylsulfate Nonahydrates
Authors: Kato Yoshifumi , Nagai Toshiyuki , Saika Apollo 
Published: July 2006

Abstract
The energy levels of the Nd3+ ion in Nd(C2H5SO4)3·9H2O and of the Er3+ ion in Er(C2H5SO4)3·9H2O are calculated within the 4fN configuration by the tensor operator method. The Hamiltonian containing a configuration interaction is diagonalized for the free ion levels and complete J-mixing is performed for the crystal field levels. The experimental “free-ion” energy levels of Nd3+ and Er3+ are fitted with a mean deviation of 70.8 cm−1 for 19 terms and 78.2 cm−1 for 22 terms, respectively. The crystal field parameters obtained for Nd(C2H5SO4)3·9H2O and Er(C2H5SO4)3·9H2O yield a mean deviation of 3.6 cm−1 for 43 levels and 3.6 cm−1 for 50 levels, respectively. The calculated Zeeman splitting factors (g values) in the direction along the crystal principal axis are in fair agreement with the experimental values.
Quantitative Analysis of Hydrogen in Titanium with an Ion Microanalyzer
Authors: Okajima Yoshiaki , Aizawa Yukiyoshi , Suzuki Katsumi , Sugawara Yasushi 
Published: July 2006

Abstract
Quantitative analysis of hydrogen in titanium was investigated with an ion microanalyzer. Argon ions as primaries were accelerated at a voltage of 10 kV. The diameter and the current of the beam were 1 mm and 2 μA, respectively. A mass spectrum was measured at 2×10−7 Torr. It was found that the intensity ratio of m⁄e=49(48TiH+) and 46(46Ti+) can be used for the determination of hydrogen in titanium. A linear relation was obtained between the intensity ratio and hydrogen concentration determined by the standard vacuum fusion method. The present method was applied to determine the hydrogen concentration in the surface layer of a sample treated by cathodic polarization. It was observed that hydrogen concentrations in the surface layer were much higher than those in the bulk of the sample.
Phase Equilibria in Sm2O3–V2O3–V2O5 System at 1200 °C
Authors: Kitayama Kenzo , Katsura Takashi 
Published: July 2006

Abstract
The phase equilibria in the Sm2O3–V2O3–V2O5 system was established at 1200 °C. In this system, Sm2O3, Sm10V2O20, SmVO3, SmVO4, V2O3, V3O5, V4O7, V5O9, V6O11 and VO2 were stable and Sm10V2O20, SmVO4, V2O3, and VO2 had the non-stoichiometry. On the basis of the phase equilibria, the Gibbs free energy for the reactions, SmVO3+1⁄2O2=SmVO4 and 4 Sm2O3+2 SmVO3+O2=Sm10V2O20, were determined to be −30.4±0.1 and −76.8±0.1 kcal, respectively. Also, standard Gibbs free energies of oxidation of various vanadium oxides were calculated.
Palladium(II) Complexes of 2,2,6,6-Tetramethylpiperidine N-Oxyl Radical
Authors: Okunaka Masaaki , Matsubayashi Gen-etsu , Tanaka Toshio 
Published: July 2006

Abstract
2,2,6,6-Tetramethylpiperidine N-oxyl radical (CH3)4C5H6NO· (TMPNO·) reacts with palladium dichloride to give complexes of both anionic and cationic TMPNO; [PdCl(TMPNO)]2 (I) and [TMPNO+]2[Pd2Cl6]2− (II). I further reacts with dimethylsulfonium phenacylide or triphenylphosphine (L) to afford a mononuclear complex of the PdCl(TMPNO)(L) type. II undergoes a facile reaction with acetone to yield bis(N-acetonyl-N-hydroxy-2,2,6,6-tetramethylpiperidinium)hexachlorodipalladate, [(CH3)4C5H6\overset+N(OH)CH2COCH3]2[Pd2Cl6]2−. Configurations of these complexes are described.
The Reaction of Aromatic Nitrile N-Oxides with Tetrahalo-p-benzoquinones
Authors: Shiraishi Shinsaku , Ikeuchi Satoru , Sen\={o} Manabu , Asahara Teruzo 
Published: July 2006

Abstract
Cycloaddition reaction of aromatic nitrile N-oxides, such as benzonitrile N-oxide, 2,4,6-trimethylbenzonitrile N-oxide, and 2,3,5,6-tetramethylbenzonitrile N-oxide, with tetrahalo-p-benzoquinones was studied. The reaction gave 1:1- and/or 2:1-adducts of a nitrile N-oxide and a tetrahalobenzoquinone according to the conditions, especially the mole ratios of each reactant. The 2:1-adducts are formed via 1:1-adducts, each having two stereoisomers. The structures of these adducts were determined to be dioxazole derivatives formed by the addition of nitrile N-oxides to the carbonyl bonds of the tetrahalobenzoquinones.
Cyanamide Derivatives. Part 106. The Preparation of 15N-Labeled Cyanoguanidines
Authors: Omura Akira , Nonaka Tsutomu , Fuchigami Toshio , Ichikawa Eiichi , Odo Keijiro 
Published: July 2006

Abstract
Methods for labeling the chemically non-equivalent nitrogen atoms of cyanoguanidine with 15N were established. 1-Cyanoguanidine-1-15N and 1-cyano-15N-guanidine were prepared, and their labeled positions were also confirmed by mass spectroscopic analysis. 15N FT-NMR spectra of cyanoguanidine enriched with 15N were measured.
Synthesis and Spectral Characteristics of 4H-1-Benzothiopyran-4-ones
Authors: Nakazumi Hiroyuki , Kitao Teijiro 
Published: July 2006

Abstract
The physical properties of 4H-1-benzothiopyran-4-ones (thiochromones) and related compounds were characterized by means of mass, NMR, and UV spectra in order to distinguish thiochromones from 2H-1-benzothiopyran-2-ones (thiocoumarins). In the mass spectra, the fragmentation due to the retro-Diels-Alder reaction directly from the molecular ion is the most useful for differentiation. In the NMR spectra, thiochromones show the characteristic deshielding effect of benzenoid proton in 5-position and in the UV spectra a very strong absorption band in the region 250–270 nm. It was found that in the reaction of S-phenyl 3-oxobutanethioates with PPA, most of these compounds afford thiochromones through rearrangement giving an intermediate (IVa). The effect of the substituent of the S-phenyl 3-oxobutanethioate on the formation of the thiocoumarin was also discussed.
Far Infrared Reflection Spectra and Lattice Vibrations of CsNiCl3 Crystal
Authors: Akiyama Kenji , Morioka Yoshiyuki , Nakagawa Ichiro 
Published: July 2006

Abstract
The frequencies of the transverse (TO) and longitudinal (LO) modes of the infrared active vibrations of the crystal CsNiCl3 were obtained from the polarized far infrared reflection spectra. The polarized Raman spectra were also measured. The calculation of the TO and LO frequencies near the center of the Brillouin zone was made on the basis of a rigid ion model which includes effective ionic charges and interionic repulsive force constants. A set of potential constants and effective ionic charges were determined from the observed values of the TO and LO frequencies and Raman frequencies using the least-squares method. The short-range force constant associated with the nickel ion to the chlorine ion indicates that some amount of covalent character is included in this bond.
Preparation of Nickel(II) Complexes with 2,3-Butanediamines and Their Thermal Octahedral-Square Planar Transformation
Authors: Nishimoto Hideyuki , Yoshikuni Tadatsugu , Uehara Akira , Kyuno Eishin , Tsuchiya Ryokichi 
Published: July 2006

Abstract
The following nickel(II) complexes with meso- or dl-2,3-butanediamine (abbreviated to meso-bn and dl-hn, respectively) were prepared: [Ni(meso-bn)3]X2·2H2O, [Ni(meso-bn)2]X2 and [Ni(H2O)2(dl-bn)2]X2 (X=Cl, Br). It was found from the changes in the absorption spectra and magnetic susceptibilities that [Ni(meso-bn)3]X2·2H2O complexes, when heated to 188 (X=Cl) and to 233 °C (X=Br), respectively, undergo transformations from octahedral to square planar structures with the loss of two moles of lattice water and one mole of coordinated meso-bn. [Ni(H2O)2(dl-bn)2]X2 complexes were similarly found to transform from octahedral to square planar structures at 120 (X=Cl) and at 110 °C (X=Br), respectively with the evolution of two moles of coordinated water. After this transformation, the resulting complexes underwent the inverse transformation from square planar to octahedral structure at 170 °C, without any weight change. The effect of the configurational difference between meso- and dl-hn on the formation of tris and bis(2,3-butanediamine) complexes is also discussed.
Vibrational Spectra of Hydantoin and Its C- and N,N′-Deuterated Compounds
Authors: Saito Yutaka , Machida Katsunosuke 
Published: July 2006

Abstract
Infrared and Raman spectra of hydantoin and its C- and N,N′-deuterated derivatives in the solid state have been recorded. The fundamental frequencies were assigned by referring to isotopic frequency shifts and vibrational spectra of related compounds. Normal coordinate analysis was carried out by using a planar Cs molecular model. A simple Urey-Bradley force field was used for the stretching and the bending coordinates and a valence force field for the out-of-plane deformation and the torsional coordinates. The force constants were refined by the least squares method to reproduce the observed frequencies.
Photo-Induced Friedel-Crafts Acylation of Anthracene with Aroyl Chlorides
Authors: Tamaki Takashi 
Published: July 2006

Abstract
The photo-excitation of anthracene (1) in the presence of benzoyl chloride and its p- or m-substituted compounds (2) gave the corresponding 2- and 9-aroylanthracenes. No isomeric 1-aroylanthracenes (3) were detected. The aroyl chlorides (2) were found to quench the fluorescence of 1. The quenching constants obtained increased with increasing electron-withdrawing ability of the substituents and are in agreement with those independently obtained from the quantum yield determinations. The efficiency of the photoaroylation was dependent on the solvent polarity. The results suggest a plausible photochemical mechanism, which involves a CT complex formed from 1 in the excited singlet state and 2 in the ground state. This complex formation is supported by the positional selectivity exhibited in the product distribution.
TEA CO2 Laser Induced Photoreactions of Ethylene, Chloroethylenes and Chloroethanes
Authors: Nagai Keiichi , Katayama Mikio 
Published: July 2006

Abstract
TEA CO2 laser induced chemical reactions of ethylene, chloroethylenes and chloroethanes have been investigated. Since these compounds have absorptions at wavelengths of 10.6 or 9.6 μm band of the CO2 laser, strong excitation of the molecular vibration gives rise to an infrared photochemical reaction. In chlorine derivatives, the cleavage of the C–Cl bond by the laser irradiation appears to initiate decompositions of these materials. The final products were mainly brought about by molecular elimination of HCl, H2, or Cl2. The present results demonstrate that the CO2 laser induced reactions differ form their thermal reactions.
N,N-Disubstituted 1,3-Dithiolan-2-iminium–TCNQ\ewdot Salts: Effect of the Substituents on the Nitrogen Atom on the Composition and the Electrical Conductivity
Authors: Araki Shingo , Tanaka Toshio 
Published: July 2006

Abstract
Following 10 simple and complex salts of TCNQ\ewdot with N,N-disubstituted 1,3-dithiolan-2-iminium cations; (Remark: Graphics omitted.) (n=1 when R1=R2=n-Pr, n-C6H13, n-C8H17, Ph, and R1=Me and R2=Ph; n=2 when R1= R2=n-Pr, n-Bu, Ph, and R1=Me and R2=Ph), and (Remark: Graphics omitted.) were prepared. Of these, simple salt (Remark: Graphics omitted.) was obtained in two different crystalline forms; unstable violet needles and green plates. All the salts as compacted samples displayed semi-conducting behaviors in the 20–90 °C range. Electrical resistivities of the 1:2 complex salts fell in the range of 5–90 ohm cm at 25 °C, while the simple and 2:3 complex salts showed much large resistivities (the order of 103–109 ohm cm). The measurements of electronic absorption spectra and magnetic susceptibilities indicated that the simple salts in the solid state involve dimeric (TCNQ)22−, except for the green salt of (Remark: Graphics omitted.) which consists of the iminium cation and discrete TCNQ\ewdot radical anion. Electronic spectra of the 1 : 2 and 2 : 3 complex salts also are discussed in comparison with analogous TCNQ\ewdot salts reported so far.
The Formation of Manganese and Cobalt Ferrites by the Air Oxidation of Aqueous Suspensions and Their Properties
Authors: Kiyama Masao 
Published: July 2006

Abstract
Manganese and cobalt ferrites were prepared by the air oxidation of aqueous suspension of Fe(OH)2 and either Mn(OH)2 or Co(OH)2 at 50–80 °C. In alkaline suspensions, all the metal ions are transformed into spinel ferrites, MxFe3−xO4 (M=Mn or Co), by a suitable combination of the oxidation temperature and the concentration of the excess NaOH. Both manganese and cobalt ferrites consist of ferromagnetic particles (ferrite(A)) when x is smaller than 1.3, nonferromagnetic particles (ferrite(B)) when x is larger than 2, and mixtures of the two in the intervening range. The contents of Mn or Co, both in a solid solution of hydroxides, Mx⁄3Fe1−x⁄3(OH)2, and in ferrite, increase with the progress of the formation of the ferrite(A) caused by oxidation. The formation of the ferrite(B) begins when x in the solid solution reaches 2. Each particle in the ferrite(A) is less homogeneous in comparison with that in the ferrite prepared by a solid-state reaction, although with the same composition. The difference in the homogeneity causes the essential difference in magnetic properties.
Ground States of the Square Planar Low-Spin Cobalt(II) Complexes
Authors: Nishida Yuzo , Kida Sigeo 
Published: July 2006

Abstract
In order to investigate the ground state configuration of some square planar cobalt(II) complexes such as Schiff base complexes of the cis-[CoN2O2] type, whose ESR spectra are quite different from those of cobalt(II) phthalocyanine and porphyrins, the spin-orbit matrix based on the four zero-order wave functions, (yz)1, (xz)1,(z2)1, and (xy) were diagonalized on assuming reasonable values for necessary parameters. The result has clearly shown that an unpaired electron is localized in dyz orbital in the ground state for these complexes. ESR spectra of a series of cobalt(II) complexes with N4-macrocyclic ligands were measured and interpreted in terms of the conclusion obtained here.
Structure-taste Relationship of Novel α-l-Aspartyl Dipeptide Sweetners
Authors: Miyoshi Muneji , Nunami Ken-ichi , Sugano Hiroshi , Fujii Toshiyuki 
Published: July 2006

Abstract
A sweetness potency was found in novel α-l-aspartyl dipeptide analogs which were quite stable on heating in an aqueous solution. The insertion of a methylene group into the peptide chain of α-l-aspartyl dipeptide esters mostly decreased the potency of the sweetness. However, the further exchange of the carbonyl and oxygen functions with each other on the ester group of a C-terminal β-alkyl-β-aminopropionic acid was found to increase the sweetness. Thus, N-(α-l-aspartyl)-O-pivaroyl-d-alaninol, N-(α-l-aspartyl)-O-cyclobutylcarbonyl-d-alaninol and N-(α-l-aspartyl)-O-cyclopropylcarbonyl-d-alaninol were all more than 200 times as sucrose.
A Comparative Study of the Photo-induced Berson-Willcott Rearrangement of Methyl 3-Isopropyl-1a,7b-dihydro-1H-cyclopropa[a]naphthalene-1-exo- and 1-endo-acetate
Authors: Kato Masahiko , Tsuji Masakazu , Miwa Toshio 
Published: July 2006

Abstract
The effect of 1-exo- and 1-endo-methoxycarbonylmethyl groups on the course of the photo-induced BersonWillcott rearrangement of methyl 1a,7b-dihydro-1H-cyclopropa[a]naphthalene-1-acetate have been studied. Different reaction rates with the same final products have been observed and are discussed from the view of the stereochemical course of the reaction, which strongly supports the 60°-mechanism, i.e., a slither motion of C-1 with inversion of configuration.
Vinyl Polymerization. 368. Polymerization of Methyl Methacrylate with the System of RNA, Water and Cu(II) Ion
Authors: Imoto Minoru , Nishida Yoshiyuki , Yoshikawa Toshiyuki , Ouchi Tatsuro 
Published: July 2006

Abstract
The radical polymerization of methyl methacrylate (MMA) was carried out with the system of ribonucleic acid (RNA), Cu(II) ion and water. The generation of free radical was found to take place in the water layer where RNA and Cu(II) ion exist. Urea shows a promoting activity. The effects of pH of water medium and temperature on the conversion of MMA were investigated. A reaction mechanism was proposed.
1,3-Dipolar Cycloadditions to Bicyclic Olefins. IV. The Influence of Non-neighboring Double Bonds on the Stereoselectivity in 1,3-Dipolar Cycloadditions to Bicyclo[n.2.2]alkadienes
Authors: Taniguchi Hisaji , Ikeda Toshikazu , Imoto Eiji 
Published: July 2006

Abstract
1,3-Dipoles, such as phenylglyoxylonitrile oxide (1), benzonitrile oxide, and phenyl azide, undergo cycloadditions to the more electron-rich double bond of 2,3-bis(methoxycarbonyl)bicyclo[2.2.2]octa-2,5-diene (5) to afford only endo adducts. The cycloadditions of these 1,3-dipoles to the more electron-rich double bond of 6,7-bis(methoxycarbonyl)bicyclo[3.2.2]nona-6,8-diene (6) give only exo adducts. Benzonitrile-N-phenylimine (4) undergoes cycloadditions to both the more electron-rich and the more electron-poor double bonds of 5 or 6. The reaction of 4 with 5 yields two endo adducts, and the reaction of 4 with 6 gives two exo adducts. However, the cycloaddition of 1 to 5,6-endo,endo-bis(methoxycarbonyl)bicyclo[2.2.2]oct-2-ene affords both the exo- and endo adducts. The reason for the predominant endo cycloadditions toward 5 and exo cycloadditions toward 6 is discussed.
The Study of Thermochemical Hydrogen Preparation. VI. A Hydrogenevolving Step through the H2S–CO Cycle
Authors: Dokiya Masayuki , Fukuda Kenzo , Yokokawa Harumi , Kameyama Tetsuya 
Published: July 2006

Abstract
A two-step decomposition process of hydrogen sulfide was studied. The process is constituted from a hydrogen-evolution step (CO+H2S\oversetca.200°C→H2+COS) and a carbonyl sulfide-decomposition step (COS\oversetca.830°C→CO+1⁄x·Sx. Almost an equilibrium amount of hydrogen could be produced in the first reaction (ca. 40%, 200 °C, 1 atm, CO/H2S=2.2) with a cobalt sulfide or nickel sulfide catalyst. In the second reaction, an almost equilibrium amount of carbonyl sulfide (45%) could also be decomposed into carbon monoxide and elementary sulfur at 830 °C under 1 atm with a sufficient reaction rate and selectivity without using any catalysts. Carbon dioxide was formed as a by-product in the second reaction: however, its yield was only 5% of the carbon monoxide produced. From these results, it may be concluded that this two-step decomposition process of hydrogen sulfide can produce more hydrogen than that produced by the direct decomposition of hydrogen sulfide. In the second reaction, however, the recombination of carbon monoxide with elementary sulfur can not be neglected. Thus, a rapid separation of sulfur from carbon monoxide is required.
Conductance Behavior of Manganese Soap Solutions in 1-Butanol and 3-Methyl-1-butanol
Authors: Varma R P , Singh K , Singh H 
Published: July 2006

Abstract
The specific conductance of manganese soap solutions in 1-butanol and 3-methyl-1-butanol has been measured at temperatures in the range 35–50 °C. Manganese soaps form micellar aggregates and the CMC, which decreases with increase in chain length of the soaps of saturated fatty acids, was found to be independent of the nature of the solvent. Conductance behavior of soaps is given by the equation logλM=A+BlogC where A and B are constants and C is the concentration in mol/dm3. Constant A increases with increase in temperature and chain length of the soap. Constant B is independent of temperature but varies with soap chain. Molecular conductance at infinite dilution, λ∞, dissociation constant, K, activation energy of conductance, ΔEλ, and heat of dissociation, ΔH°, have been evaluated.
The Verification of Three-Dimensional Aromaticity: Tricarbonyliron Complexes of Olefins
Authors: Aihara Jun-ichi 
Published: July 2006

Abstract
Using Mingos’s Hiickel molecular-orbital model, polyolefins were found to be markedly aromatized by the coordination of tricarbonyliron. The Dewar-type resonance energies calculated for the title compounds are consistent with their chemistry.
An Infrared Study of Acid Sites on Silica-Alumina Catalysts Poisoned with Sodium Hydroxide
Authors: Take Jun-ichiro , Ueda Toshiaki , Yoneda Yukio 
Published: July 2006

Abstract
We investigated the effect of NaOH impregnation on the acidic properties (the type, strength, and amount of acid sites) of silica-alumina by means of IR spectroscopy of chemisorbed pyridine. Most acid sites on the unpoisoned catalyst were of the Lewis type. Some Lewis-bound pyridine was retained on the surface even at 400 °C, but the pyridinium ion was eliminated at 300 °C, indicating that the strong acid sites were also of the Lewis type. Impregnated NaOH affected both Lewis and Brønsted sites. An increase in the amount of NaOH resulted in the elimination of the Brønsted acid sites of medium strength, and also in a significant reduction in the number of Lewis acid sites over the whole range of acid strength. Weak Brønsted acid sites showed no marked change in number. When the NaOH-impregnated catalysts were exposed to pyridine, a new IR band appeared at about 1445 cm−1; this band is attributable to pyridine associated with the Na ions on the surface.
Studies of the Metal Complexes of Cyclohexane Derivatives. IV. Copper(II) and Nickel(II) Complexes of 1,2-Cyclohexanediamine Isomers
Authors: Saito Reiko , Kidani Yoshinori 
Published: July 2006

Abstract
Two types of copper(II) complexes, Cu(c-chxn)2X2·nH2O and Cu(t-chxn)2X2·nH2O (X=Cl−, Br−, NO3−, and ClO4−, n=0–2), and three types of nickel(II) complexes, [Ni(c-chxn)2]X2, [Ni(c-chxn)3]X2·nH2O (X=Cl−, Br−, NO3−, and ClO4−, n=0.5–1.5) and [Ni(t-chxn)2(H2O)2]X2 (X=Br− and ClO4−), were synthesized. Here, c-chxn and t-chxn stand for cis- and trans-1,2-cyclohexanediamine respectively. Based upon the analyses of the electronic spectra and magnetic moments, the structures of the copper(II) complexes synthesized were found to be distorted octahedrons. The influence of the steric configurations of the diamine isomers on the structures of the copper(II) complexes is small. The three types of nickel(II) complexes were found to have square planar, octahedral, and distorted octahedral structures respectively. The steric influence of the ligands on the properties of the nickel(II) complexes was also considered.