bluuebunny/crossref_metadata_2025 huggingface dataset:
Three Methods to Look at Walsh-type Diagrams Including Nuclear Repulsions
Authors: Takahata Yuuzi , Parr Robert G
Published: July 2006

Energy correlation diagrams for molecules of type AH2 are examined by three different methods: (1) the quantum-mechanical virial theorem, (2) the method of median partition, (3) the integral Hellmann-Feynman theorem. Nuclear-nuclear repulsions are included. The formula for the first method takes the form W=−Σti, where ti is an orbital kinetic energy. The theory is applied to H2O, CH2, and BeH2. Negative-kinetic-energies-versus-angle diagrams for these molecules are presented. The pattern of the diagrams is quite different from the usual Walsh diagram. With this resolution non-bonding electrons play a significant role in determining bond angles. In the second method the resolution of the total energy takes the form W=Σi[ei+Vn(i)], where ei is a median electronic energy and Vn(i) is a resolved nuclear repulsion energy calculated from an expression derived from ideas of population analysis. The energies-versus-angle diagram thus obtained for H2O is similar to the one obtained by the first method. For the third method, the integral Hellmann-Feynman formula for the electronic energy change on bending is written in terms of corresponding orbital contributions, ΔEl=ΣiΔEl(i), and nuclear-nuclear repulsion is added in a resolved form. For H2O the ΔEl resemble Walsh diagrams closely, both with and without the nuclear-nuclear repulsion increments. Wave functions used throughout are LCAO-SCF functions built from medium-size Gaussian basis sets.
On the EPR Emission Spectrum of Transient Naphthosemiquinone Radical
Authors: Yoshida Hiroshi , Sohma Junkichi , Warashina Tetsuo
Published: July 2006

EPR spectrum in emission mode at the low-field hyperfine lines was observed for 1,4-naphthosemiquinone radical formed by the steady-state photolysis of solution of corresponding quinone in ethanol flowing through the cavity. Observed behavior of this spectrum was analyzed by a phenomenological way. The results support the view that the anomalous electron spin polarization is generated in the radical formation process. The conclusion was compared with the results of intermittent photolysis.
Topochemical Studies. III. The Crystal and Molecular Structures of Crotonic Acid, CH3CH=CHCOOH, and Crotonamide, CH3CH=CHCONH2
Authors: Shimizu Shozo , Kekka Shinji , Kashino Setsuo , Haisa Masao
Published: July 2006

Crotonic acid crystallizes in the monoclinic space group C2/c, with a=15.30(3), b=4.06(1), c=16.18(2) Å, β=107.4(1)° and Z=8; crotonamide in the monoclinic space group P21/a, with a=9.71(2), b=6.90(2), c=7.75(1) Å, β=104.0(4)° and Z=4. The structures have been solved by the Patterson method and refined by the block-diagonal least-squares method. The final R values are 0.090 for 337 observed reflections for crotonic acid, and 0.088 for 525 observed ones for crotonamide. The configuration of the molecules of crotonic acid and crotonamide is approximately planar and of trans-type regarding the C=C bond. Every two centrosymmetrically related molecules form a dimer through hydrogen bonds of 2.645 Å (OH···O) for crotonic acid and 2.963 Å (NH···O) for crotonamide. In the crystals of crotonamide additional NH···O hydrogen bonds (2.862 Å) link the neighboring molecules related by the a-glide plane to form a sheet parallel to (001) plane. Distances between the C=C bonds of the nearest neighbors are 3.86 Å for crotonic acid and 3.62 and 3.88 Å for crotonamide.
Polarographic and Anodic Stripping Polarographic Studies of Aliphatic Polyamine Complexes of Several Metal Ions
Authors: Komatsu Masahiro
Published: July 2006

The polarography of several aliphatic polyamine complexes of Pb(II), Zn(II), and Ni(II), and the anodic stripping polarography of polyamine complexes of Zn(II), Cd(II), Pb(II), and Cu(II) were studied. The aliphatic polyamines used were ethylenediamine(en), 1,3-propanediamine(1,3-pn), 1,2-propanediamine(1,2-pn), diethylenetriamine(den), and triethylenetetramine(trien). These lead(II) complexes gave a one-step reversible wave which was diffusion-controlled. The relation between the logarithm of the concentration of polyamine and the halfwave potential of the Pb(II) complex was straight, so that one species of complex ion was found to be predominant in the bulk of solution. The ionic species in the bulk of solution were found to be Pb(en)22+, Pb(1,3-pn)22+, Pb(1,2-pn)22+, Pb(den)22+, and Pb(trien)2+. The stability constants of these complexes were calculated and were found to increase in the order of Pb(1,3-pn)22+<Pb(en)22+<Pb(1,2-pn)22+<Pb(den)22+<Pb(trien)2+. The polarographic waves of Zn(II)-polyamine and Ni(II)-polyamine complexes were irreversible and diffusion-controlled, so the electrode reactions of these complexes were assumed using Matsuda-Ayabe’s theory. All these polyamine complexes of Zn(II), Cd(II), Pb(II), and Cu(II) gave well-defined anodic stripping polarograms. 1,3-pn was the best complexing reagent among these polyamines, because it gave the best separation of the peaks of the anodic stripping polarograms of the four metal ions. Calibration curves were obtained from 0.01 to 0.10 ppm for Zn(II), Pb(II), and Cu(II), and from 0.001 to 0.010 ppm for Cd(II) in 0.4 M 1,3-pn and 0.2 M KCl media. The effects of acid and base on the anodic stripping polarograms were also studied.
The Complexing of the Sodium Ion in Acetonitrile with Other Solvents. Investigation by the Use of a Cationsensitive Glass Electrode
Authors: Izutsu Kosuke , Nomura Toshiaki , Nakamura Toshio , Kazama Hidetoshi , Nakajima Shigeo
Published: July 2006

The complexing of the sodium ion in acetonitrile (AN) with such solvents as methanol, water, DMF, DMA, DMSO, HMPA, and pyridine has been studied potentiometrically by using a monovalent cation-sensitive glass electrode. The reference electrode of Ag-0.005 M AgNO3(AN) and the salt bridge of 0.1 M Et4NPi(AN) were used. Mono- and di-solvated ions were formed for methanol, water, and pyridine. For DMF, DMA, DMSO, and HMPA, tri-solvated species were also formed. The formation constants for the mono-solvated sodium ion were 0.7 for pyridine, 1 for methanol, 1.8 for water, 2.5 for DMF, 5 for DMA, 6 for DMSO, and 30 for HMPA.
Effect of Ethanol on the Outer-sphere Association of Λ- or Δ-Tris(ethylenediamine)cobalt(III) with d-Tartrate Ions in Aqueous Solutions
Authors: Yoneda Hayami , Miyoshi Katsuhiko , Suzuki Shingo , Taura Toshiaki
Published: July 2006

The effect of ethanol on the outer-sphere association of Λ- or Δ-[Coen3]3+ ion (en=ethylenediamine) with d-tartrate ion was investigated in aqueous solutions containing 0,1,3, and 5 wt% of ethanol at 25 °C by measuring the change in optical density of the charge-transfer spectra at 265 nm. It was found that the association constant of Λ-[Coen3]3+ ion with d-tartrate ion KA(Λ) was a little larger than that of Δ-[Coen3]3+ ion KA(Δ), and that the addition of ethanol increased both KA(Λ) and KA(Δ) but decreased the ratio KA(Λ)⁄KA(Δ). The diminished discrimination between Λ- and Δ-[Coen3]3+ ions by d-tartrate ion was discussed in terms of the solubility of these diastereoisomers in aqueous ethanol and was attributed to the increased electrostatic interaction between the complex and d-tartrate ions arising from the decrease in the dielectric constant of the medium.
Potentiometric and Spectrophotometric Studies of Fluoride Complexes of Uranium(IV)
Authors: Kakihana Hidetake , Ishiguro Shin-ichi
Published: July 2006

The stability constants and the molar extinction coefficients of uranium(IV) fluoride complexes were determined in aqueous solutions containing 1 M (Na++H+)Cl− as a constant ionic medium at 25 °C. The emf data obtained by the use of a fluoride-ion-selective electrode were explained in terms of the formation of a series of mononuclear complexes, UF3+, UF22+, UF3+, and UF4, with stability constants β1=(2.2±0.13)×107, β2=(1.33±0.05)×1013, β3=(2.9±0.5)×1017, and β4=(6±1)×1021 respectively. Using these values for β’s the spectra observed in the 350–700 nm region were analyzed by means of a computer in order to estimate the molar extinction coefficients of each uranium(IV) fluoride complex species.
Carbonylation of Alcohols, Olefins, and Saturated Hydrocarbons by CO in the Ag(I)–H2SO4 System
Authors: Souma Yoshie , Sano Hiroshi
Published: July 2006

In the presence of an Ag carbonyl-ion catalyst, prepared in situ from the Ag compound and carbon monoxide in H2SO4, olefins or alcohols reacted with carbon monoxide at room temperature and atmospheric pressure to produce exclusively tertiary carboxylic acids in high yields. The amount of Ag compound sufficient for carrying out the reaction is ca. 0.2 mol/l. The optimum reaction temperature is 0–40°C. The reaction proceeds practically at above a 90% H2SO4 concentration. Saturated hydrocarbons, containing a tertiary hydrogen, also reacted with carbon monoxide in the presence of alcohols or olefins as carbonium ion precursors, thus producing tertiary carboxylic acids.
Règies Concernant la Stéréochimie de L’ Hydrogénation Catalytique
Authors: Brown Eric , Ragault Michel
Published: July 2006

The rule of maximum compactness is put forward as a guide for establishing the stereochemistry of catalytic hydrogenation in many cases. This rule complements the well-known Auwers-Skita rule.
Stéréochimie des Perhydrobenz(e) Indénones-2
Authors: Brown Eric , Ragault Michel
Published: July 2006

The stereochemistry is given of various perhydrobenz(e) inden-2-ones, which have been synthesized as potential intermediates for C-nor-D-homo-steroids.
The Reaction of 3-(ω-EthoxycarbonyIacetyl)-2H-cyclohepta[b]furan-2-one with Active Methylene Compounds
Authors: Nozoe Tetsuo , Takase Kahei , Nakazawa Tomoo , Sugita Satoko , Saito Motoyasu
Published: July 2006

The reaction of 3-(ω-ethoxycarbonylacetyl)-2H-cyclohepta[b]furan-2-one (4) with malononitrile and with cyanoacetamide, in the presence of sodium ethoxide, gave 4-hydroxyazuleno[2,1-b]pyrid-2(1H)-one derivatives, (5) and (9) respectively, in good yields. On the other hand, the reaction of 4 with ethyl cyanoacetate gave 3-cyano2-ethoxycarbonylmethylazulene-1-carboxylic acid (12). The structures of these products were determined on the basis of the spectral data and some chemical evidences.
New Photochemical Reactions of 9-ω-Bromoacetylanthracene. I
Authors: Matsumoto Tamotsu , Sato Masanori , Hirayama Satoshi
Published: July 2006

New photochemical reactions were found on 9-ω-bromoacetylanthracene. The main photo-products were 1-aceanthrenone and 9-bromoanthracene. Their formation was not appreciably affected by the presence of oxygen. Other products such as anthracene, 9-acetylanthracene and anthraquinone were also detected and their yields greatly depended on the reaction conditions. From the low temperature experiments, it was made clear that 9-bromoanthracene and 1-aceanthrenone were formed via different mechanisms. A rather stable intermediate, which was not a radical but presumably an intramolecular adduct, was detected spectroscopically. 1-Aceanthrenone was formed from the intermediate both photochemically and thermally with liberation of hydrogen bromide. In the absence of oxygen both the thermal and photochemical reactions of the intermediate yielded almost the same amount of 1-aceanthrenone. The reaction mechanisms were considered in reference to the photochemical reactions of 9-nitroanthracene and sodium 9-anthroate. The relation between these reactions and the radiationless transition processes of carbonyl derivatives of anthracene was also discussed.
Phase Diagrams of YCl3–KCl, YCl3–NaCl, and YCl3–KCl·NaCl Systems, and Densities of Their Molten Mixtures
Authors: Mochinaga Junichi , Irisawa Kyozan
Published: July 2006

YCl3 has been prepared with Y2O3 and NH4Cl, and the optimum conditions for chlorination have been determined. The YCl3 salt obtained was purified to a pure YCl3 crystal by sublimation. Pnase diagrams of binary YCl3–KCl and YCl3–NaCl system, and liquidus curve diagram of quasi-binary YCl3–KCl·NaCl system have been determined with the use of the purified YCl3 crystal. Densities of YCl3 and the mixtures in molten state were measured dilatometrically, and represented by empirical formulas as a function of temperature. From the results thermal expansion coefficients and molar expansibilities of the molten YCl3 and the molar volumes of molten mixtures were calculated.
Electron-transfer Kinetics of Transition-metal Complexes in Lower Oxidation States. Part II. The Electrochemical Electron-transfer Rate of the Cr(bipy)3+/Cr(bipy)3 System as Measured by the Galvanostatic Double-pulse Method
Authors: Saji Tetsuo , Aoyagui Shigeru
Published: July 2006

The kinetic parameters of the electron-transfer reaction, Cr(bipy)3++e\ightleftharpoonsCr(bipy)3, were measured by the galvanostatic double-pulse method at a dropping mercury electrode in N,N-dimethylformamide. The apparent and the corrected standard rate constants were 1.0±0.2 and 0.3 cm s−1 respectively, and the transfer coefficient was 0.6±0.1 at 25 °C. These rate constants were discussed in comparison with the corresponding homogeneous rate constant on the basis of the theoretical equation of Marcus. They were quite inconsistent with the value, 103 cm s−1, predicted from the corresponding homogeneous rate constant.

The polarograms of Cr(bipy)3+ and Cr(bipy)3 exhibited three waves with half-wave potentials of −0.21, −0.65 and −1.19 V vs. a cationic glass electrode. The diffusion coefficients of these complexes, as determined polarographically, were identical: 3.2×10−6 cm2 s−1 at 25 °C.
Tri(hetero)substituted Carbonium Ions. VII. Effect of the Ring System on the Ambident Reactivity of Cyclic Dithiocarbamidium Ions
Authors: Nakai Takeshi , Hiratani Kazuhisa , Okawara Makoto
Published: July 2006

In order to study the effect of structure on the ambident reactivity of cyclic dithiocarbamidium ions, two endo-imimum type cations, 2-methylthio-3-methyl-4,5-dihydrothiazolium ion (5) and 2,3,5,6-tetrahydrothiazolo-[2,3-b]-thiazolium ion (6) were prepared. Their electrophilic reactivities were studied and compared with those of the exo-iminium type cations, 2-dimethylamino-1,3-dithiolan-2-ylium ion (1) and its ring analogues. 3-Di-methylamino-2,4-benzodithiepan-3-ylium ion (7) was prepared and its ambident reactivity was studied. Examination of the products obtained from their reactions with various nucleophiles revealed that the three cation have two reactive sites, i.e., the central (sp2) carbon (site a) and the S-methylene (or S-methyl) (sp3) carbon atoms (site b). Significant differences in the electrophilic behavior of the endo- and exo-iminium type cations were observed. They were discussed in terms of the structures as estimated from the spectra. Kinetic experiments showed that the reactivities at site a of these cations with hydroxide ion, relative to that of 1, are 22.5 (5): 16.6 (6): 27.2 (7), and at site b with N,N-dimethyldithiocarbamate ion are 3.3 : 282 : >104. The reactivity order suggests that the reactivities at the two sites, especially at site b, are very sensitive to a change in the ring system of the cations.
Substituent Effects on the 13C and 1H Chemical Shifts of 1-Phenyl-1,3-butadiene and Phenylallene
Authors: Okuyama Tadashi , Izawa Kunisuke , Fueno Takayuki
Published: July 2006

CMR and PMR spectra of trans-1-phenyl-1,3-butadiene (PBD) and phenylallene (PA) and their ring-substituted derivatives (p-CH3, m-CH3, p-Cl, and m-Cl) have been measured. The chemical shifts of side-chain carbons and protons were treated with a Hammett-type relationship. The carbon chemical shifts of the side chain gave alternately opposite sign of ρ values while those of PA showed little dependence on the ring substitution. The 1H chemical shifts showed behavior different from that of the 13C shifts. The mode of electron polarization along the side-chain of PBD and PA was discussed to interpret the observations.
8,5′-O-Cyclonucleosides of Tubercidin
Authors: Anzai Kentaro , Matsui Masanao
Published: July 2006

On treatment with NBS, 2′,3′-O-benzylidenetubercidin (1) and its isopropylidene analogue (6) afforded the 8,5′-O-cyclonucleosides 2 and 7 respectively. Catalytic hydrogenation of 2 and 7 afforded the dehalogenated compounds, 9 and 12.
The Proton Magnetic Resonance in the DPPH–Benzene Complex
Authors: Yoshioka Toshio , Ohya-Nishiguchi Hiroaki , Deguchi Yasuo
Published: July 2006

The proton magnetic resonance in single crystals of the DPPH–benzene complex has been measured around three Cartesian axes. All the spectra are highly complex, but some lines are clearly identified around all axes. The principal values of their anisotropic hyperfine tensors have been evaluated, in addition to the isotropic hyperfine coupling constants. In the crystalline state, the unpaired electron-spin distributions of one phenyl group is almost twice as large as that of the other phenyl group, as is to be expected from the crystal structure. Besides, the unpaired electron-spin delocalization is larger in the crystalline state than that in solution, particularly on the picryl group and on one phenyl group.
The Reaction of Ethyl Ethoxymethylenecyanoacetate with Its Hydrazino Derivatives
Authors: Saito Koji , Hori Isaburo , Igarashi Minoru , Midorikawa Hiroshi
Published: July 2006

The reaction of ethyl ethoxymethylenecyanoacetate with its hydrazino derivative in the presence of pyridine in ethanol at room temperature gave ethyl (4-ethoxycarbonyl-5-aminopyrazol-1-yl)methylenecyanoacetate(6) and two geometric isomers of ethyl (4-ethoxycarbonylpyrazol-5-ylamino)methylenecyanoacetate(7). Compound 6 itself, under the same conditions, rearranged to compound 7. Both compounds, 6 and 7, upon heating cyclized exclusively to the same product, diethyl 7-aminopyrazolo[1,5-a]pyrimidine-3,6-dicarboxylate(8). From the results of other combination reactions on methylenecyanoacetic ester homologs, a plausible reaction mechanism involving a rearrangement is discussed.
Computer-assisted In-phase AC Polarography: Determination of Cadmium (II) Ions
Authors: Fujiwara Shizuo , Hirota Michio , Sawatari Katsuhiko , Kojima Hiroyuki , Umezawa Yoshio
Published: July 2006

An on-line polarograph is used to detect the in-phase component of the ac response. The applied ac voltage and resulting current are sampled simultaneously and multiplied and then integrated. The detection limit of Cd(II)(0.1M KCl) is 1.85×10−7M by accumulation.
The Reactions of 2-Hydroxystilbenes with Lead Tetraacetate and Manganic Acetate
Authors: Nogami Keifumi , Kurosawa Kazu
Published: July 2006

Four 2-hydroxystilbenes (Ia∼Id) were oxidized with lead tetraacetate to give corresponding 3-arylbenzofurans (IIa∼IId) in moderate yields. IId and IIe were also obtained by the reactions of Id and Ie respectively with manganic acetate in poor yields.
The Activating Effects of Amino Groups in Diazo-coupling Reactions
Authors: Hashida Y\={o}ji , Takenaka Junichi , Matsui Kohji
Published: July 2006

The rates of the reactions of various aromatic amines with diazotized sulfanilic acid have been studied. It was found that, among the N,N-disubstituted anilines, the activating effect of amino groups is roughly proportional to their pKa values.
The Crystal and Molecular Structure of meso-(2S,4s,6R)-2,4,6-Heptanetriol
Authors: Kuribayashi Shunsuke
Published: July 2006

The crystal structure of meso-(2S,4s,6R)-2,4,6-heptanetriol has been determined by means of X-ray methods. The crystal belongs to monoclinic system (space group Ic), with four molecules in a unit cell with dimensions of a=8.133, b=9.374, c=11.248 Å, and β=93.24°. The structure was solved by three-dimensional Patterson and trial-and-error methods. The final R factor was 0.076. The molecule has the GTT\barG conformation, and all of the OH groups are linked together by intermolecular hydrogen bonds.
Ultrasonic Study on Solute-Solvent Interaction in Aqueous Systems of Ethers
Authors: Takenaka Nobuo , Arakawa Kiyoshi
Published: July 2006

Ultrasonic velocity and absorption were measured for binary mixtures of water and ethers (1,2-dimethoxyethane, bis(2-ethoxyethyl)ether, bis (2-methoxyethyl)ether, ethylether, diethoxymethane, 1,1-diethoxyethane and 1,2-diethoxyethane) in the frequency range 15–45 MHz at 10–30 °C. Vibrational relaxation was observed in the pure liquid of 1,2-dimethoxyethane. For each solution of 1,2-dimethoxyethane and bis(2-methoxyethyl)ether, the maximum absorption at the intermediate composition was ascribed to the formation of dihydrate and trihydrate, respectively. The difference between the behavior of ethyl group in water and that of methyl group was discussed from the absorption data.
Kinetic Studies of the Nickel Glycolate Complex Formation in Solution by the Pressure-Jump Method
Authors: Harada Shoji , Okuue Yozo , Kan Haruki , Yasunaga Tatsuya
Published: July 2006

The nickel glycolate complex formation reaction was studied by the pressure-jump method and the kinetic parameters were obtained. The rate-determining step of the reaction was revealed to be the chelate-ring for mation process.
Infrared Absorption Spectra and Normal Coordinate Analysis of Metal-Dl-Tyrosine Chelates
Authors: Inomata Yoshie , Inomata Tadaaki , Moriwaki Takao
Published: July 2006

The infrared absorption spectra of Dl-tyrosine and six metal Dl-tyrosine chelates have been investigated from 4000 to 300 cm−1. A detailed normal coordinate analysis was performed for the metal chelates as a 39-body problem and an approximate description of the vibrational modes has been assigned to the observed frequencies. Dl-Tyrosine chelates are found to be coordinated with the metal through nitrogen and oxygen and to have a trans configuration; the same is true for other aliphatic amino acid chelates. The bond-stretching force constants for the metal-nitrogen bonds have been found to decrease in the order Pd(II)>Cu(II)>Zn(II)>Cd(II)>Ni(II)>Co(II). The calculated frequencies, which were obtained using the same force constants as in other aliphatic amino acid chelates, were in good agreement with the observed frequencies.
THE SOLUBILITIES OF SILVER SALTS
Authors: Masaki Kosaku
Published: July 2006

The solubilities of silver cyanide, thiocyanate, bromide and carbonate in water at 18°C. have been determined by the electromotive force measurements, and obtained the values:

(Remark: Graphics omitted.)
Palladium(II) Complexes Derived from the Reactions of Bis(3-hydroxy-2-methyl-4-pyronato)palladium(II) with Several Nitrogen Bases
Authors: Morita Hideyoshi , Shimomura Shigeru , Kawaguchi Shinichi
Published: July 2006

The preparation and properties of the palladium(II) amine complexes containing 3-hydroxy-2-methyl-4-pyronate ions as the counter anions, [Pd(N)4]L2 and [Pd(NN)2]L2·nH2O, are reported, where N=propylamine or benzylamine, NN=ethylenediamine, trimethylenediamine or N,N′-dimethylethylenediamine, HL=3-hydroxy-2-methyl-4-pyrone, and n=2–4. The unidentate-amine complex, [Pd(N)4]L2, reacts with Nal to afford [PdI2(N)2], whereas the bidentate-amine complex, [Pd(NN)2]L2·nH2O, reacts with Nal to give [Pd(NN)2]I2. The mixed-ligand complexes, [PdL(bpy)]X and [PdL(phen)]X (where bpy=2,2′-bipyridine, phen=1,10-phenanthroline, X=ClO4 or B(C6H5)4), are also reported. On the basis of the PMR spectra, the IR spectra, and the electric conductivities, the structures of the isolated complexes are discussed.
The Separation of Tin from Water and Sea-water by Flotation and the Determination of Tin by Atomic Absorption Spectrophotometry Following Stannane Generation
Authors: Nakashima Susumu
Published: July 2006

A method is described for the separation and determination of sub-microgram levels of tin in water. A submicrogram amount of tin(II, IV) in a 1000-ml sample of water is coprecipitated with iron(III) hydroxide at pH 4.0±0.2. The precipitate is floated with the aid of sodium dodecyl sulfate and small air bubbles, and then separated and dissolved in 2 ml of 6 M hydrochloric acid and diluted to 10 ml with water. Finally, the tin content is determined by the generation of stannane, using sodium borohydride as a reductant, followed by atomic absorption spectrophotometry with a long absorption cell (60×1.2 cm i.d.). This separation technique has also been successfully applied to the determination of sub-microgram amounts of tin in natural sea-water. The time required for the pre-concentration of tin from a 1000-ml volume of solution is about 15 min per sample after 15 min of stirring.
Crystal and Molecular Structure of trans-1,4-Dibenzoyl-2,5-dimethylpiperazine
Authors: Okamoto Kojun , Sekido Kiyotane , Itoh Jun , Noguchi Teruo , Hirokawa Sakutaro
Published: July 2006

The crystal structure of trans-1,4-dibenzoyl-2,5-dimethyl-piperazine has been determined by the X-ray method. The space group is P21/c, with a=7.483, b=6.577, c=19.939 Å, β=116.71° and Z=2. The structure was solved by the direct method and refined by the least-squares method to the final R factor of 0.094 for 2559 independent reflections. A nitrogen atom and three carbon atoms bonded to the nitrogen atom are approximately in a plane. The molecule is centrosymmetric, the piperazine ring having a chair-form. The methyl groups are in the axial position. The oxygen atom is approximately in a plane formed by N, C(carbonyl), and C(benzene). The dihedral angle between this plane and the benzene ring is approximetely 70°.
Determination of Ultratrace Zinc by Enzymatic Activity of Carbonic Anhydrase
Authors: Kobayashi Kensei , Fujiwara Kitao , Haraguchi Hiroki , Fuwa Keiichiro
Published: July 2006

A method for the determination of trace zinc has been investigated by using enzymatic activity of carbonic anhydrase. The recovery of enzymatic activity of apo-carbonic anhydrase was proportional to the amount of zinc in solution theoretically and experimentally, when it was monitored spectroscopically using the substrate, p-nitrophenyl acetate. The amount of zinc in the sample solutions was therefore determined from the curve, zinc concentration vs. the enzymatic activity. The limit of detection is 10 ng/ml or 2 ng. The method has been applied to the analysis of zinc in fruit juices and water samples.
Electrochemical Behavior of Ferredoxins Adsorbed on Mercury Electrode Surface. Cyclic d.c. and a.c. Voltammetric Studies with Hanging Mercury Drop Electrode
Authors: Ikeda Tokuji , Toriyama Kazunobu , Senda Mitsugi
Published: July 2006

The electrochemical behavior of Clostridium pasteurianum ferredoxin and spinach ferredoxin was studied by cyclic d.c. and cyclic phase-selective a.c. voltammetry with a hanging mercury drop electrode. An irreversible adsorption of these ferredoxins on the electrode surface is described. In successive cyclic voltage scans both d.c. and a.c. voltammograms of ferredoxins change gradually in both height and form until a steady state is attained, indicating that the ferredoxins adsorbed on the electrode surface decompose to cluster-free ferredoxins. Apoferredoxins give the same voltammograms as the steady state voltammograms of ferredoxins. The steady state voltammograms are assigned to RSH/RSHg redox reaction of the cysteine residues in apoferredoxin. At pH lower than 8 the d.c. waves are explained by an equation for reversible one-electron surface redox reaction. Kinetic parameters of the redox reaction were determined by a.c. voltammetry.
The Reaction of ω-Ethoxyalkyl Bromides with Silver(I) Cyanide and Nitrite. The Participation of an Oxonium Ion
Authors: Watanabe Nanao , Uemura Sakae , Okano Masaya
Published: July 2006

The reaction of ω-ethoxyalkyl bromides (Cn: n=2–5) with silver(I) cyanide or nitrite in less polar solvents to give the corresponding isocyanide or a mixture of the corresponding alkyl nitrite and nitroalkane respectively, proceeded with ease only when n=4. In the latter reaction, the ratios of O- and N-attack (O/N) were 16–18/ 82–84 and 31–46/54–69 when n\eweq4 and n=4 respectively. The facile reaction in both cases when n=4 and the increasing O-attack in the case of silver(I) nitrite may suggest that the reaction proceeds through the initial formation of a five-membered oxonium ion, the O-ethyltetrahydrofuranium ion, and a subsequent attack by CN− and NO2− or their silver(I) bromide complex.
Hydrolytic Reactions of p-Nitrophenyl Esters in Reversed Micellar Systems
Authors: Fujii Hirotada , Kawai Tohru , Nishikawa Hiroyasu
Published: July 2006

Hydrolytic reactions of several p-nitrophenyl esters were studied with and without catalysts in reversed micellar systems consisting of sodium octanoate, 1-hexanol and water. Hydrolytic rate constants become very large as compared with those in aqueous solutions, increasing with decrease in the molar ratio of water to sodium octanoate (R-value). The results of kinetic measurements were discussed in terms of the behavior of water molecules and polar groups of sodium octanoate as revealed by means of IR and 1H, 13C and 23Na-NMR spectroscopy. It was concluded that the decrease in the R-value induces the increase in the mobility of water molecules and the decrease in the polarity of the water core, which affects the partition coefficient of p-nitrophenyl esters between the 1-hexanol phase and the water phase, enhancing hydrolytic reactions.
Chemistry of N-Thiosulfinylanilines. II. Thermolysis and Photolysis of N-Thiosulfinylanilines
Authors: Inagaki Yoshio , Okazaki Renji , Inamoto Naoki
Published: July 2006

Thermolysis of 2,4-di-t-butyl-6-methyl-N-thiosulfinylaniline (1) in refluxing benzene afforded 2,4-di-t-butyl-8-thia-9-azabicyclo[4.3.0]nona-2,4,6,9-tetraene (6) and 2,4-di-t-butyl-6-methylaniline (7), while its photolysis resulted in the formation of N,N′-bis(2,4-di-t-butyl-6-methylphenyl)sulfur diimide (17) and 7. The mechanism of the thermolysis involving 1,5-hydrogen migration and o-quinonoid intermediate has been proposed. The electronic spectrum of the initial intermediate in the photolysis was obtained in EPA matrix and tentatively assigned to a dithionitro compound (42) or a dithiaziridine (41). Thermolysis of 2,4,6-tri-t-butyl-7,8-dithia-9-azabicyclo[4.3.0]nona-2,4,9-triene (4b) equilibrated with 2,4,6-tri-t-butyl-N-thiosulfinylaniline (4a) gave 4,6-di-t-butyl-3H-1,2,3-benzodithiazole 2-oxide (26) and 2,4,6-tri-t-butylaniline (27). The reaction in the presence of a catalytic amount of p-toluenesulfonic acid improved the yield of both 26 and 27, suggesting the ionic decomposition pathway. However, an ESR signal was observed during the thermal decomposition of 4 in the absence of oxygen, implying a concurrent homolytic pathway if not a major one. The mechanism of these reactions are briefly discussed. The photolysis of 4 led to 27 and N,N′-bis(2,4-di-t-butyl-6-methylphenyl)sulfur diimide (43).
Crystal and Molecular Structure of ω-Amino Acids, ω-Aminosulfonic Acids and Their Derivatives. IX. Crystal and Molecular Structure of 3-Amino-2-hydroxy-1-propanesulfonic Acid
Authors: Kim Yang Bae , Bando Sachiko , Hombo Toshiyasu , Fujiwara Takaji , Tomita Ken-ichi
Published: July 2006

The crystal structure of 3-amino-2-hydroxy-1-propanesulfonic acid was determined by MULTAN system with X-ray intensity data on a diffractometer and refined by the least-squares method to an R-value 0.087 for 1620 reflections. The crystals were orthorhombic, space group Pbca, Z=8, with a=9.909, b=12.032 and c=10.251 Å. The molecule takes the zwitterionic form, H3+NCH2CH(OH)CH2SO3−. The skeletal conformation of the molecule is planar trans zigzag. The molecules are held together by three-dimensional network of hydrogen bonds.
Chemical Reaction of Electron Donor-Acceptor System: Reaction Mechanism of the Tricyanovinylation Reaction of N,N-Dimethylaniline with Tetracyanoethylene
Authors: Nogami Takashi , Nakano Yoshio , Hasegawa Yoshiki , Shirota Yasuhiko , Mikawa Hiroshi
Published: July 2006

The decay of the charge-transfer (CT) absorption band in the tricyanovinylation reaction of N,N-dimethylaniline (DMA) with tetracyanoethylene (TCNE) in 1,2-dichloroethane was followed by the electronic absorption measurement. Primary hydrogen isotope effect was observed for the decay of the CT-band in line with the mechanism:

[D+A\ightleftharpoonsDA]→I

I+D→NA

NA+D\undersetslow→P

D: DMA; A: TCNE; DA: CT-complex; I: zwitterionic intermediate; NA: p-(1,1,2,2-tetracyanoethyl)-N,N-dimethylaniline; P: p-tricyanovinyl-N,N-dimethylaniline.
Degradation of Magnesium and Calcium Highpolyphosphate Coacervates
Authors: Umegaki Takao , Kanazawa Takafumi
Published: July 2006

The degradation of highpolyphosphates in the coacervates of magnesium and calcium is discussed on the basis of the results of viscosity measurement and paper chromatographic analysis of highpolyphosphates. The initial viscosity and transparency of some magnesium coacervates were maintained with little change at 30 °C for about 2 weeks, while most calcium coacervates changed within 10 days into wet cakes containing Ca(H2PO4)2·H2O and Ca3(HP2O7)2·4H2O. The formation of pyrophosphates during the course of degradation of both coacervates is remarkable as compared with that on the hydrolysis of alkali highpolyphosphates in aqueous solutions.
Transpiration Study of the Reaction of Water Vapor with Barium Oxide
Authors: Sasamoto Tadashi , Mizushima Kentar\={o} , Sata Toshiyuki
Published: July 2006

Barium oxide has been found to react with water vapor at temperatures from 1443 to 1593 K to form gaseous Ba(OH)2 according to the reaction; BaO(s)+H2O(g)→Ba(OH)2(g). The standard free energy of formation is given by the equation, ΔGr°=49400–16.6 T (cal/mol) in the present temperature range. From the thermodynamic cycle the bond energy between barium and two hydroxyl groups has been found to be 196.8 kcal/mol.
Phase Relations in the Sulfur-rich Portion of the Fe–V–S System at Temperatures between 520 and 814 °C
Authors: Wada Hiroaki
Published: July 2006

An equilibrium study of a part of the Fe–V–S system at sections with atomic Fe:V ratios 1:1, 3:2, and 71:29 was carried out. A gravimetric method using a quartz spring balance was employed in the range of log(PS2/atm)=−4 to −0.8 at temperatures between 520 and 814 °C. Phase relations in the sulfur-rich portion of the Fe–V–S system were examined on the basis of the PS2-T-X relation and X-ray analyses of the quenched specimens. The phase diagram of the Fe–V–S system was tentatively constructed at about 570 °C. The compositional dependence of the lattice parameters of the (Fe,V)3S4 solid solution was studied from the crystallographic viewpoint.
The Condensation Products of Naphthanthrone
Authors: Fujisawa Shoji , Aoki Junji , Takekawa Minoru , Iwashima Satoshi
Published: July 2006

Three hydrocarbons, with absorption maximum at 510 nm, 533 nm, and 567 nm respectively, have been synthesized by the condensation of naphthanthrone in a mixed flux of zinc chloride and sodium chloride with copper powder. The structures of the hydrocarbons have been determined by comparison with the products obtained by the alkali fusion and reduction of naphthanthrone and 2-bromonaphthanthrone.
Structure of the Rearrangement Product of Dihydromayurone with Boron Trifluoride in Acetic Acid-Acetic Anhydride at 50 °C
Authors: Sekizaki Haruo , Ito Masaaki , Inoue Shoji
Published: July 2006

The structure of the second main product, 4-acetoxy-1,7,8-trimethyltricyclo[5.4.0.04,8undec-9-ene, in the rearrangement reaction of dihydromayurone with boron trifluoride in acetic acid-acetic anhydride at 50 °C, and reaction mechanism is presented and discussed.
A Facile Synthesis of 4,5-Dialkoxy-o-benzoquinones by the Oxidation of Catechol with Iodates in Alcohol
Authors: Itoh Yuji , Kakuta Takuya , Hirano Masao , Morimoto Takashi
Published: July 2006

4,5-Dimethoxy-o-benzoquinone has been prepared by the oxidation of catechol with sodium iodate in methanol. In higher alcohols, the same oxidation occurs in the presence of a crown ether to give the corresponding 4,5-dialkoxy-o-benzoquinones. In the latter cases using 18-crown-6, the potassium salt is more effective than the sodium salt.
Empirical Formula for Mass Transfer across the Boundary between Convections in a Two-layer System
Authors: Kamakura Katsuyoshi
Published: July 2006

When a two-layer system which consists of water (upper layer) and an aqueous solution (lower layer) is heated from one side and cooled from the opposite side, a convection starts in each layer and a sharp horizontal boundary is formed by the two flows in opposite directions. The empirical formula for the transfer of a solute across the boundary was obtained by measuring the change in the concentration of a solute in the upper layer. The flux, WA, of a solute, A, was expressed by

W A=a3(Δρ1–Δρ0)D0.5(ΔcI⁄Δρ2).

Here, a3 is the mass-transfer coefficient; Δρ1, the density difference between the liquid on the heated wall and that on the cooled wall; Δρ0, the value of Δρ1 at which the convections start; D, the diffusion coefficient of a solute; and ΔcI and Δρ2, the concentration difference and the density difference, respectively, between the solution of the upper layer and that of the lower layer.
Raman Spectra of Alkali Metal Oxalates in Aqueous Solution. Evidence for Ion-pair Formation
Authors: Kanamori Kan , Mihara Masamitsu , Kawai Kiyoyasu
Published: July 2006

Laser Raman spectra of aqueous solutions of lithium, potassium, and caesium oxalates have been obtained; their band contours were examined by curve analysis. The intensities of several bands show distinct concentration and cation dependences. This behavior is connected with the ion-pair formation of oxalate ions with alkali metal cations. The assignments of C=O stretching vibrations are also discussed.
Thermodynamic Study of the Self-association of 6-Methylpurine in Water-1,4-Dioxane Solvent
Authors: Morimoto Satoshi
Published: July 2006

Determination of the thermodynamic quantities of the self-association of 6-methylpurine in water(1)–1,4-dioxane(2) (x2=0–0.36) mixed solvent has been made from heat of dilution measurements in various organic contents, at 25 °C. It was confirmed experimentally that the dissociation process of associating purine bases in solution is very fast by dilution. It was characteristic of this solvent system that the standard enthalpy and entropy changes, ΔH° and ΔS°, of the association exhibited an abrupt behavior. These values decrease remarkably with 1,4-dioxane content up to a water-rich solvent composition below x2=0.012. After that, they approach their relatively high values for the pure organic component, at first with a steep slope, later more gradually. This behavior is related to the structural changes of the solvent in an extremely sensitive way. In the case of water (1)–methanol(2) (x2<0.19) mixed solvent system which has been investigated for comparison with the above system, minimum values of the same kind were found in the vicinity of x2=0.12, at 25 °C.
Differential Determination of Tellurium(IV) and Telluriiim(VI) by Atomic Absorption Spectrophotometry after Hydride Generation. Combined Use of Titanium(III) Chloride as a Prereductant and Sodium Borohydride Solution
Authors: Jin Kazuo , Taga Mitsuhiko , Yoshida Hitoshi , Hikime Seiichiro
Published: July 2006

Sensitive determination of tellurium was investigated by atomic absorption spectrophotometry after hydride generation and differential determination of tellurium(IV) and tellurium(VI) in acidic solution was carried out. When sodium borohydride solution is used without any prereductant, only the signal from tellurium(IV) is obtained. On the other hand, when titanium(III) chloride solution is added before the addition of borohydride solution, total signal from tellurium(IV) and tellurium(VI) can be obtained; 30—60 s of prereduction is required. The effectiveness of the titanium(III) chloride-borohydride reduction system is shown in the interference study. The interference of selenium(IV) is eliminated up to 200 fold vs. 0.25 μg of tellurium(IV) in 20 cm3 of 3 mol dm−3 hydrochloric acid by the use of 2 cm3 of 5% w/v titanium(III) chloride solution as a prereductant. Tellurium in steel and sulfur (commercial reagent) can be determined satisfactorily without isolation of tellurium from matrix by this method. Detection limit of the method is 8 ng. The coefficient of variation of the method is 2.4% in the ten determinations of 0.25 μg of tellurium.
Studies of the Metal Complexes of Cyclohexane Derivatives. VI. The Thermal Transformation of Nickel(II) Complexes of 1,2-Cyclohexanediamine Isomers
Authors: Saito Reiko , Kidani Yoshinori
Published: July 2006

The thermal transformations of the following three types of nickel(II) complexes were investigated by means of TG-DSC analyses: [Ni(t-chxn)2(H2O)2]X2, [Ni(c-chxn)3]X2·nH2O, and [Ni(t-chxn)3]X2·nH2O (X=Cl−, Br−, and NO3−), where c- and t-chxn denote cis- and trans-1,2-cyclohexanediamine respectively. The distorted octahedral [Ni(t-chxn)2(H2O)2]X2 complexes (X=Cl− and Br−) are thermally deaquated to form yellow complexes, which then turn into parental diaquabis-complexes in the air at room temperature. [Ni(t-chxn)2(H2O)2] (NO3)2 undergoes a thermal deaquation-anation reaction. The octahedral tris(c-chxn) complex is converted into a square planar bis(c-chxn) one by the evolution of one molecule of the ligand upon heating, whereas tris(t-chxn) complex became a distorted octahedral bis(t-chxn) one with anion coordination. In this paper, the stereochemical thermal changes of the complexes in the solid state will be discussed with regard to the steric configuration of the ligands.
Acetoxymethylation of Coumarins by Manganese(III) Acetate
Authors: Kurosawa Kazu , Harada Hironobu
Published: July 2006

The reactions of 4-methoxy-, 7-methoxy-, 6,7-dimethoxy-, and 7,8-dimethoxycoumarins with manganese(III) acetate in boiling acetic acid containing acetic anhydride gave 3-(acetoxymethyl) coumarins as the major product. The reactions of coumarin, and 6-methoxy- and 8-methoxycoumarins with manganese(III) acetate yielded a mixture of 3-(diacetoxymethyl)- and nuclear acetoxymethylated coumarins. The reaction of 7-methoxycoumarin with lead(IV) acetate gave 7-methoxy-3-methylcoumarin.
Electron-organic Chemistry. IV. Structure—Anodic Potential Relationship and Electron-transfer-induced Reactions of [2.2]Para- and -Metaparacyclophanes
Authors: Sato Takeo , Torizuka Koichi , Shimizu Motomu , Kurihara Yukio , Yoda Noriko
Published: July 2006

The anodic peak potentials of [2.2]para- and -metaparacyclophanes were found to be highly dependent on the solvent. A cleavage reaction occured when [2.2]paracyclophane was electrolyzed anodically, using acids or alcohols as nucleophilic solvents, whereas lead tetraacetate oxidation in trifluoroacetic acid–dichloromethane gave nuclear substitution products. The cathodic reduction in hexamethylphosphoric triamide–lithium chloride–acetic acid gave 1,2-di-p-tolylethane and its Birch reduction products. On anodic oxidation, [2.2]metaparacyclophane gave a rearrangement reaction product, 4-hydroxy[2.2]metacyclophane. Possible reaction pathways for these reactions were formulated.
A Study of Catalysis by Metal Phosphates. V. The Alkylation of Toluene with Methanol over Metal Phosphate Catalysts
Authors: Sodesawa Toshiaki , Kimura Isao , Nozaki Fumio
Published: July 2006

The side chain alkylation of toluene with methanol over the catalyst of Ca3(PO4)2 or K3PO4 supported on active carbon gave more ethylbenzene than that over MgO. It was found that there are correlations between the catalytic activities and acid-base properties.
Analysis of Glass Films Prepared from Alkoxides on Glass Substrates
Authors: Iino Akira , Mizuike Atsushi
Published: July 2006

Sodium in 50 nm thick ZrO2–SiO2 glass films has been determined by secondary ion mass spectrometry. A remarkable sodium contamination from the Pyrex glass substrate has been confirmed.
Rayleigh Ratio for Benzene and Its Temperature Dependence
Authors: Kamata Toshio , Nakahara Hisae
Published: July 2006

The temperature dependence of the Rayleigh ratio for benzene was studied for the purpose of comparing various reported values obtained at different temperatures with each other. The following relationship was obtained for a wavelength of incident light of λ0=435.8 nm:

R 90=(0.1377t+43.06)×10−6cm−1

where t is temperature (°C). Light-scattering photometers were calibrated with benzene purified by a preparative gas chromatograph by using a value of the Rayleigh ratio for benzene of R90=46.5×10−6cm−1 (25 °C, λ0=435.8 nm). In order to verify the validity of the calibrations, molecular weight determinations were run on three standard substances: egg white lysozyme, raffinose, and sucrose. The temperature of benzene was directly measured by inserting the sensor of a thermistor thermometer into the benzene within the cell.
Emission Spectra of 1,4-Naphthoquinone and Its 2-Methyl Derivative in the Vapor Phase
Authors: Itoh Takao , Baba Hiroaki
Published: July 2006

The emission spectra of 1,4-naphthoquinone (NQ) and 2-methyl-1,4-naphthoquinone (MNQ) vapors have been investigated at various temperatures in the presence of added foreign gases (≈100 Torr). The results indicate that in both NQ, and MNQ, the emission consists of T1(n, π*)→S0 phosphorescence and weak E-type delayed fluorescence, S1(n, π*)→S0, the latter lying at higher frequencies. This new interpretation of the vaporphase emission spectra of the naphthoquinones, which is substantially different from the interpretations given by previous authors, is based on and consistent with the following observations: (1) When the temperature is raised, the ratio of the fluorescence intensity to the phosphorescence intensity increases; (2) the S1–T2 energy separations, 1365±60 and 1500±200 cm−1 for NQ, and MNQ, respectively, determined from the temperature dependence of the emission intensities agree with the corresponding values obtained from spectral data; (3) the emission lifetimes obtained by monitoring the fluorescence and phosphorescence are identical.
Resistmetric Study of the Potential-sensitive Surface Layer Formed on VO2 Electrode in a Neutral Solution
Authors: Nakamura Toyohisa , Haruyama Shiro
Published: July 2006

The formation of a potential-dependent surface layer on VO2 electrode has been investigated from the change in conductance of a thin VO2 film electrode by galvanostatic polarization. The VO2 electrode dissolved as vanadate with 100% current efficiency by anodic polarization. At potentials negative to the immersion potential, the VO2 electrode functioned as an insoluble electrode with the formation of the potential-dependent surface layers of the vanadium oxides by lower valence. The change in composition of the surface layers was traced by resistmetry and coulometry, and illustrated against the amount of electric charge passed, taking V7O13, V6O11, V5O9, V4O7, V3O5, and V2O3 as the possible oxides. The composition at vanadium oxides of outer-most layer was plotted against the electrode potential. The plot shows a multi-step figure as in the equilibrium partial pressures of oxygen on vanadium oxides at high temperatures, suggesting a model in which the composition of the outer-most layer of the oxide responds to the electrode potential applied.
Hydrogen-Deuterium Equilibration Reaction over Platinum Supported on Polyamide-6
Authors: Inoue Yasunobu , Hacho Seiji , Miyazaki Eizo , Yasumori Iwao
Published: July 2006

Catalysis by platinum supported on polyamide-6 was examined for the H2-D2 equilibration reaction at 0 °C in the pressure range of 5–20 Torr (1 Torr=133.3 Pa). Three kinds of polyamides with different molecular weights were prepared as support; the concentration of platinum varied from 0.5 to 2.7 wt%. With preadsorption of hydrogen at 0 °C, the rate of the reaction was found to increase up to 10 times as high as the original level. The rate km (HD molecule s−1Pt atom−1) showed a maximum, depending on surface area of the polyamides used, in the range 0.8–1.0 wt% of Pt content and its dependence on total pressure is represented by km=K1P⁄(1+K2√‾P)2 irrespective of Pt content. No significant isotope effect was observed at 0 °C. It was found that a linear relationship exists between the enhancement of km and the amount of hydrogen preadsorbed, indicating an important role of the preadsorbed hydrogen in activation of the catalysts. In contrast to km, the turn-over frequency kt (HD molecule s−1 site−1) was nearly independent of Pt concentration. The exchange reaction is explained in terms of the Bonhoeffer-Farkas mechanism. XPS spectra provided the evidence for the presence of Pt(II) complexes on the surface. The structure of active sites is discussed.