bluuebunny/crossref_metadata_2025_split huggingface dataset:
Thermoluminescence from the UV-Irradiated Solution of Triphenylmethane at Low Temperature
Authors: Yamamoto Naoto , Matsumura Michio , Tsubomura Hiroshi 
Published: July 2006

Abstract
Triphenylmethane, irradiated in the near ultraviolet region in a non-polar rigid medium at 77 K, showed thermoluminescence consisting of three bands, fluorescence and phosphorescence of triphenylmethane and fluorescence of triphenylmethyl radical. With the increase of solute concentration the yield of the emissions from triphenylmethane decreased while that of the emission from the radical increased. It was concluded that the emissions from triphenylmethane were due to the recombination between triphenylmethane cation and the photoejected electron, and that the fluorescence from the radical was mainly due to the electron transfer reaction between triphenylmethane cation and triphenylmethyl anion. Detailed emission processes inlcuding electron transfer and energy transfer processes were discussed.
Transmission of Substituent Effects through the Oxygen and Sulfur Atoms. IV. CNDO/2 Charge Distributions in Vinyl and Divinyl Ethers and Sulfides
Authors: Kajimoto Okitsugu , Kobayashi Masaru , Fueno Takayuki 
Published: July 2006

Abstract
Charge distributions in vinyl methyl and divinyl ethers and their sulfur homologs bearing a polar substituent at the trans-β position were calculated by the CNDO/2 method. It was found that the effect of substituents on charge distribution is transmitted primarily through the successive π-polarization of the ethylenic units involved. In the divinyl compounds, the sulfur atom on the spd basis is calculated to transmit the substituent effects more effectively than the oxygen atom. The greater transmission efficiency of the sulfur atom is interpreted in terms of the pπ-dπ-pπ conjugation.
Nuclear Quadrupole Effects in the Microwave Spectrum and Dipole Moment of Aniline
Authors: Hatta Aritada , Suzuki Masao , Kozima Kunio 
Published: July 2006

Abstract
The quadrupole hyperfine structure was resolved and analyzed for the vibrationally-ground state of the NH2 species. The quadrupole coupling constants are: χaa=2.34, χbb=1.86, and χcc=−4.20 MHz. The rotational constants obtained from the quadrupole corrected frequencies are as follows: A=5617.67, B=2593.88, and C=1777.04 MHz. The rotational constants of the ND2 species in the vibrationally-ground state were also determined. By the use of the moments of inertia of both species, the non-planarity of this molecule was ascertained. The dipole moments of the NH2 and the ND2 species were determined to be 1.15±0.02 D and 1.13±0.01 D respectively.
The Photoconductivity of Poly(N-vinylcarbazole). III. Photoconductivity in a Sandwich-type Cell.
Authors: Okamoto Kenichi , Kusabayashi Shigekazu , Mikawa Hiroshi 
Published: July 2006

Abstract
Photoconductivity in a sandwich-type cell of a PVCz film was investigated in a high vacuum and in the air. A large photociirrent was observed in the π–π* absorption region and a small photocurrent in the visible region. The former showed the following interesting points in its behavior. In low applied fields, no difference was found between the photoconductivity with positive-electrode illumination and that with negative-electrode illumination. In moderate or high fields, however, the photoconductivity with positive-electrode illumination was significantly different from that with negative-electrode illumination. The former showed a superlinear dependence on the applied field (consequently, iph+&gt;&gt;iph−) and a spectral response coinciding with the absorption spectrum. This photoconductive behavior was explained by assuming the mechanism of carrier generation, namely, the fieldassisted thermal dissociation of exciplexes and the detrapping of trapped carriers by singlet excitons. Carriers are supposed to migrate through the overlap of π-electrons of neighboring carbazyl rings in the same polymer chain.
Studies of the Preparation and Physical Properties of Multivalent Metal Condensed Phosphates. V. The Grinding of Various Aluminum Phosphates
Authors: Tsuhako Mitsutomo , Motooka Itaru , Kobayashi Masamitsu 
Published: July 2006

Abstract
Changes in the structures of various aluminum phosphates as a result of grinding were studied by a variety of physical methods—X-ray analysis, DTA, TGA, infrared absorption spectroscopy and electron microphotography, and their acidic properties were investigated in order to obtain information on the surface activity of the compounds. The X-ray diffraction patterns indicated that the A, B, and C types of Al4(P4O12)3 and AlPO4 (Berlinite) did not become completely amorphous even after grinding for 72 hr; this shows that the crystal structures of these compounds were relatively stable to grinding. Substance K was structurally more fragile than the other aluminum phosphates (Al4(P4O12)3, AlPO4), becoming completely amorphous on being ground for 72 hr. On DTA and TGA, the ground aluminum phosphates exhibited an endothermic peak, accompanied by a weight loss due to the loss of adsorbed water in the vicinity of 100°C. A further weight loss at higher temperatures was presumably due to dehydration caused by the condensation of P–OH. The amounts of acids on the ground aluminum phosphates were almost independent of the acid strength, which was around +1.5 (pKa). The amounts of acids of the A, B, and C types and of AlPO4 tended to increase slightly with the grinding time. The amount of acid of the K substance reached a maximum after 6 hrs grinding but decreased slowly when grinding was continued for longer than 15 hr.
Variational Calculation of Atoms and Molecules by a Modified Hassé Method Using Hulthén Functions. III. Long-range Interactions between Hydrogen Atom and Proton and between Two Hydrogen Atoms
Authors: Yamabe Tokio , Ishimaru Shingo , Fukui Kenichi 
Published: July 2006

Abstract
The variation method using the wave function of the modified Hassé form is applied to the problem of long-range interactions between hydrogen atom and proton and between two hydrogen atoms. The interaction energy is also related to the perturbation energy under the Unsöld approximation by the use of several pertinent approximations, and an “improved second-order Unsöld energy,” which will be higher than the exact second-order perturbation energy, is newly proposed. The numerical results show that the present trial wave function is quite effective; particularly, at R\gtrsim10 (a.u.), the dispersion energy between hydrogen atoms is better than that of Hirschfelder-Linnett, which might be the best variational result at a large nuclear separation. Furthermore, the importance of considering the degeneracy in treating the induction energy is numerically disclosed for an example of H–H+ interaction. The coefficients in the asymptotic form of the dispersion energy between two hydrogen atoms are briefly discussed, and, finally, a new method for the calculation of the second-order energy is suggested.
The Crystal Structure of Quinolinic Acid
Authors: Takusagawa Fusao , Hirotsu Ken , Shimada Akira 
Published: July 2006

Abstract
The crystal structure of quinolinic acid (2,3-pyridinedicarboxylic acid) has been determined by the method of X-ray diffraction. The crystal is monoclinic, with a space group of P21/c and with cell dimensions of a=7.421, b=12.729, c=7.850 Å, and β=116.96°. The crystal structure was solved by the inspection of a Patterson map. The final R value was 6.78% for 1224 observed reflections. The quinolinic acid molecule takes the form of a zwitter ion in the crystal. The pyridine ring in the molecules shows a significant deformation from the C2V symmetry of idealized geometry. The lengths of the two C–C bonds joining the carboxyl groups to the ring are longer than the normal value. There is an intramolecular hydrogen bond between the adjacent carboxyl groups. The bond lengths in the two C–O groups which participate in this intramolecular hydrogen bond are longer than those of the other two C–O groups. One of the two carbonyl oxygen atoms participates in a hydrogen bond, while the other is free from it. The molecules are arranged in layers closely parallel to the (0 1 0) plane. Each molecule on the same plane is hydrogen-bonded to form an endless chain along the a axis. These chains are packed by the van der Waals forces. The thermal diffuse scattering observed on Weissenberg photographs can be explained by this hydrogen-bond system.
Studies on Intermolecular Complex Formation. III. Crystal Structure of Thymine-N,N-Diethylmelamine Complex Monohydrate
Authors: Tamura Chihiro , Hata Tadashi , Sato Sadao 
Published: July 2006

Abstract
The crystal and molecular structure of the thymine-N,N-diethylmelamine complex monohydrate has been solved by means of the direct method. The crystals are monoclinic, with the space group of P21/c and with a=7.167, b=16.123, c=13.179 Å, and β=104.2°. The final R-factor for 1612 reflections is 0.087. These two components are hydrogen-bonded by a NH···N and two NH···O bonds with distances of 2.881, 2.821, and 3.006 Å. The complex formation ability for thymine and uracil has also been tested for some other organic compounds with amino and nitrogen heterocycles.
Optical and Magnetic Studies of CuSeO3·2H2O Based on the Refined Crystal Structure
Authors: Asai Takeshi , Kiriyama Ryôiti 
Published: July 2006

Abstract
Magnetic, IR and electronic spectral studies were made on CuSeO3·2H2O, its crystal structure being refined. The IR band at 927 cm−1 was found to be due to a rocking vibration of a water molecule. The H-bonding scheme was suggested. The electronic spectrum shows a maximum of the d-d transition bands at ca. 14000 cm−1. This was explained on the basis of a square pyramidal coordination of a Cu ion. Above 100 K the magnetic susceptibility obeys the Curie-Weiss law with θ=−92·6 K and μeff=2.00βB. At lower temperatures it shows a broad maximum at ca. 45 K, a sharp peak at 26.4 K corresponding to TN. The behaviour could be explained from the antiferromagnetic superexchange interactions of Cu cations through the σ-bonds of SeO32− anions. The small anisotropy and the number of cations intermediated by each anion give rise to the 1-dimensional character. A linear Heisenberg model and the molecular field model gave J⁄k values of −33 and −31 K, respectively. The latter model also gave the observed ratio of |θ|⁄TN.
Structural Studies of Tryptophan Metabolites by X-ray Diffraction Method. I. The Crystal and Molecular Structure of 5-Hydroxy-Dl-Tryptophan
Authors: Wakahara Akio , Kido Masaru , Fujiwara Takaji , Tomita Ken-ichi 
Published: July 2006

Abstract
5-Hydroxy-Dl-tryptophan was crystallized from a methanol solution in the monoclinic space group C2/c, with cell-dimensions of a=16.765, b=5.892, c=20.887 Å, and β=92.06°. The molecular structure and stereoconfiguration have been elucidated by the direct method for non-primitive space group. A Fourier map, calculated with the largest 198 normalized structure factors as Fourier coefficients, revealed the whole structure which was refined by the least-squares method. The molecule is a zwitterion as in the crystal structure of amino acids, each amino nitrogen atom having an extra proton. The indole ring plane forms a dihedral angle of 40° with that formed by an acid group. With respect to the conformation about the C(α)–C(β) bond, the orientation of C(β)–C(γ) bond is trans with respect to the C(α)–COO–. The molecules are arranged in double layers parallel to the ab-plane. The layer by polar groups is held together by a series of hydrogen bonds in a three-dimensional network, and by non-polar groups in the other layer, indole rings being stacked by van der Waals forces. The d-and l-forms of 5-hydroxytryptophan are hydrogen-bonded into two types of dimer related by the center of symmetry, one through N–H···O, and the other through O–H···O hydrogen bonding.
Crystal and Molecular Structure of ω-Amino Acids, ω-Aminosulfonic Acids and Their Derivatives. V. Crystal and Molecular Structure of γ-Guanidino Propane Sulfonic Acid
Authors: Kim Yang Bae , Wakahara Akio , Fujiwara Takaji , Tomita Ken-ichi 
Published: July 2006

Abstract
The crystal structure of γ-guanidino propane sulfonic acid was determined by the symbolic addition method with X-ray intensity data on a diffractometer and refined by the least-squares method to an R-value 0.069 for 1963 reflections. The crystals were monoclinic, space group P21/c, Z=8, with a=10.080, b=8.013, c=19.716 Å and β=98.17°. Two independent molecules in the asymmetric unit both have a zwitterionic form, (NH2)2+CNHCH2CH2CH2SO3−. There are two forms, trans zigzag and cis ones, which are linked by N(1)H···O hydrogen bonds. The molecules are held together in the crystal by a three-dimensional network of NH···O hydrogen bonds.
Reactions of Diphenylphosphinothioyl Isothiocyanate and Related Compounds with Some Nucleophiles and Carbodiimides
Authors: Ojima Iwao , Akiba Kin-ya , Inamoto Naoki 
Published: July 2006

Abstract
Diphenylphosphinothioyl isothiocyanate (1) reacted with alcohols, water and diphenylphosphinothioic acid to give the esters and anhydride of diphenylphosphinothioic acid by substitution reaction on the phosphorus atom, but reacted with amines by addition to the isothiocyanate group to afford diphenylphosphinothioylthioureas or their ammonium salts. Diphenylphosphine and p-toluenethiol, however, did not react with 1. On the contrary, diphenylphosphinothioyl isocyanate underwent only addition reaction with water, amine and thiol. Isothiocyanate (1) and p-toluenesulfonyl isothiocyanate were found to undergo 1,2-cycloaddition reaction with carbodiimides across the C=S bond to produce 1,3-thiazetidine derivatives.
Synthesis of Carbocydic Adenosine Analogs: 9-(2′,3′,4′,5′-Tetrahydroxycyclopentyl)adenines
Authors: Suami Tetsuo , Nishiyama Shigeru , Tadano Kinichi , Lichtenthaler Frieder W 
Published: July 2006

Abstract
The synthesis of five 9-(2′,3′,4′,5′-tetrahydroxycyclopentyl)adenines with 1,2,4/3,5- (2a), 1,2,3/4,5- (2b), 1,4,5/2,3- (2c), 1,4/2,3,5- (2e) and all-cis configuration (2d) are described, by animation of 4-amino-5-nitro-6-chloropyrimidine with the respective 5-aminocyclopentanetetrols (3a–e), followed by reduction of the nitro group and cyclization with formamide.
Prelimimnary anyifungal properties are reported.
Some Doping Effects on the Semiconducting Properties of Gd2CuO4
Authors: Kenjo Tadao , Yajima Seishi 
Published: July 2006

Abstract
Some doping effects on the semiconducting properties of the Gd2CuO4 compound were investigated. The ZrO2 or ThO2 (0.5 mol%) lowered the resistivity of the Gd2CuO4 at room temperature by a factor of 104. The thermoelectric powers of the same samples were negative. These were explained as being due to the Cu+ ions formed by the dopants. The CaO dopant lowered the resistivity by a factor of ten and converted the sign of the thermoelectric power from negative to positive. The resistivity of the BaO-doped samples increased with an increase in the dopant concentration up to 0.5 mol%, and decreased with an increase in the dopant concentration in the concentration region lower than that. This suggested that the dopant of BaO was less effective on the resistivity-lowering than was the CaO. The samples doped with the ZrO2 and CaO simultaneously gave a trend similar to those doped with the BaO in the concentration dependence of the resistivity. Silver oxide and indium oxide were also employed as dopants, but no doping effects were observed on either resistivity or the lattice parameters.
Studies of the DNA–Acridine Complexes. I. Fluorescence Depolarization
Authors: Kubota Yukio 
Published: July 2006

Abstract
The motion of the DNA–acridine complexes in solution was studied by the fluorescence depolarization method. Five derivatives of 3,6-diaminoacridine were used in order to investigate the effect of amino substituion on the depolarization results. A linear relation between the reciprocal polarization (1/P) and T/η was obtained by varying the temperature of a native DNA–acridine solution. The limiting polarization (P0) and the mean rotational relaxation time (ρh) of the complex were evaluated from these data. The ρh value of the complex (30–50 nsec) was much larger than the value of free acridine in water, but it was much too small to correspond to the rotation of the whole DNA molecule. Further, it was found that the values of P0 and ρh for 3,6-bis(diethylamino)acridine are much smaller than those for other acridines. This may result from some steric hindrance of the binding by bulky diethylamino groups.
Mechanism of Hydrogenolysis. III. Thermal Hydrogen Exchange and Demethylation of Toluene-2-d1, -3-d1, and -4-d1
Authors: Sato Yoshiki , Amano Akira 
Published: July 2006

Abstract
Rates of gas phase thermal hydrogen exchange and hydrogenolytic demethylation of toluene-2-d1, -3-d1, and -4-d1 are evaluated using flow apparatus at temperatures 675–750 °C in the presence of a large excess molecular hydrogen. Both the exchange and the demethylation obey three-halves order rate law indicating the chain mechanism carried by hydrogen atom, the former being found slightly faster than the latter. Rate parameters of the two reactions taking place concurrently are then correlated with the extended Hückel superdelocalizability values appropriate to methylcyclohexadienyl transient formation. Overall applicability of the dynamic index as a measure of reactivity of deuteriotoluenes toward hydrogen atom attack is taken as an additional support for the generally accepted chain mechanism whose rate-determining step consists of electroneutral hydrogen atom addition to aromatic nucleus.
Simulation Analysis of the Acid–catalyzed Hydrolysis of Carboxylatopentammineruthenium(III) Complexes
Authors: Ohkubo Katsutoshi , Sakamoto Hiroyuki , Kitagawa Futoshi , Ohyoshi Akira 
Published: July 2006

Abstract
The mechanism of the acid-catalyzed hydrolysis of (NH3)5RuO2CR2+ (R=H, CH3, C2H5, (CH3)2CH, CH2OH, and/or CH2NH2) has been established by the trapezoidal simulation analyses with a computer. The proposed reaction sequences of SN1 combined with SN2 mechanisms involving a quasi-stable intermediate (NH3)5Ru3+ have proved to be plausible, and the kinetic parameters (rate constants, ΔH\eweq, ΔS\eweq, etc.) have been given for all of the elementary reactions. The aquation rate has been determined by the solvent-assisted, heterolytic dissociation of (NH3)5RuO2CR2+ and follows this order: formato&gt;acetato&gt;propionato&gt;isobutyrato&gt;glycolato&gt;glycinato.
Charge Transfer in Acetonitrile–Halogen Complexes
Authors: Negita Hisao , Shibata Kaoru , Furukawa Yoshihiro , Yamada Koji 
Published: July 2006

Abstract
The charge transfer in acetonitrile-halogen complexes was examined by means of the nuclear quadrupole resonances resulting from the relevant nuclei. 14N NQR parameters (|e2Qq|=3.6000 MHz and η=0.0183) and 35Cl NQR parameters (|e2Qq|=107.44 and 108.50 MHz) were obtained for the acetonitrile-chlorine complex, whereas 14N NQR parameters (|e2Qq|=3.5439 MHz and η=0.0043) and a 81Br NQR parameter (|e2Qq|=640.52 MHz) were obtained for the acetonitrile-bromine complex. From these parameters, the charged states of the nitrogen, chlorine, and bromine atoms in these charge-transfer complexes were calculated by means of the Townes and Dailey theory. In the case of the acetonitrile-bromine complex, the charge loss at the nitrogen atom was not equal to the gain at the bromine atom, as long as the charge was assumed to be transferred only to the p-orbital of the latter. This discrepancy was explained by assuming some d-hybridization at the bromine atom. The charged states of the nitrogen atoms in these complexes were qualitatively in good agreement with the electron affinities of the chlorine and bromine molecules. Moreover, the temperature dependences of the 14N and 81Br nuclear quadrupole coupling constants in the acetonitrile-bromine complex were investigated in the range from −196 to −60 °C.
Counterion Effect on the Titration Behavior of Poly(maleic acid)
Authors: Muto Nobuhiko , Komatsu Tsuyoshi , Nakagawa Tsurutaro 
Published: July 2006

Abstract
The potentiometric titration of poly(maleic acid) (PMaA) in aqueous solutions containing alkali metal salts and a tetramethylammonium salt was carried out at 25 °C, and the effect of the counterions on the titration behavior of PMaA was examined in detail. The acidity of the primary carboxylic groups of PMaA increases in the order of (CH3)4N+&lt;Li+&lt;Na+&lt;K+, whereas that of the secondary carboxylic groups increases with the decrease in the crystallographical radius of the counterions, in agreement with the results for ordinary polycarboxylic acids. The order of K+&gt;Na+&gt;Li+ for the binding strength to the primary carboxylate groups of PMaA is interpreted in terms of the radius of the hydrated cations; it can be attributed to the stable ring structure of the monoanion of the maleic acid residue, resulting from the hydrogen bonding between two adjacent carboxylate groups.
Solvent Effect in Electron Spin Resonance Spectra and Electrochemical Reaction of Substituted Nitrobenzene Anion Radicals
Authors: Fujinaga Taitiro , Deguchi Yasuo , Umemoto Kisaburo 
Published: July 2006

Abstract
In order to examine the effect of solvents on the hyperfine splittings of anion radical the electron spin resonance spectra of substituted nitrobenzene anion radicals were studied. The effect of hydroxylic solvent is enhanced when the nitro group is forced out of the plane of the benzene ring due to the steric influence of the bulky functional group at the ortho position. The effect is reduced when the nitro group forms intramolecular hydrogen bond with the hydroxyl group at the ortho position. A model for the solvent effect considering the hindered rotation of the nitro group in the radical molecule caused by the formation of intermolecular hydrogen bond with solvent is found to be reasonable from a molecular orbital calculation, taking account of changes in molecular orbital parameters resulting from hydroxylic solvation. The shifts in polarographic half wave potentials with the solvent system as well as the dehalogenation reaction in the course of electrochemical reduction of halonitrobenzenes is interpreted by means of the model.
Studies on Fragment Ion Distribution and Reactions with the Use of a Charge Spectrometer. IV. Dependence of Cross Sections of Some Ion–Molecule Reactions on the Kinetic Energy of Ions
Authors: Nagatani Toshio , Yoshihara Kenji , Shiokawa Takanobu 
Published: July 2006

Abstract
Gross sections of methylamine and methanol for ion-molecule reactions with various rare gases have been studied by means of a charge spectrometer used as a double mass spectrometer. The results differed from those predicted by the Gioumousis-Stevenson theory. The difference was most pronounced for helium ion, the lightest ion.
Ultrasonic and Thermodynamic Studies on the Aqueous Solutions of Tetramethylurea
Authors: Sasaki Katsutaka , Arakawa Kiyoshi 
Published: July 2006

Abstract
Ultrasonic absorption and sound velocity were measured for aqueous solutions of tetramethylurea at temperatures 10–30 °C. Excess compressibility and partial molar volume were obtained. The curves for the concentration dependence of density, viscosity, and absorption show a maximum at about 60 vol% (20 mol%). The excess compressibility curve shows a minimum at the same concentration. It is concluded that a molecular complex of the molar ratio 4: 1 (water: tetramethylurea) linked with hydrogen-bonds is formed at 20mol%. In a dilute solution (below 4mol%), the magnitude of ultrasonic absorption of tetramethylurea solutions is equal to that of 1,3-dimethylurea solutions, but is less than that of 1,3-diethylurea solutions. The tetramethylurea–water interaction is of a similar nature to that between 1,3-dimethylurea and water in a dilute solution.