bluuebunny/crossref_metadata_2025_split huggingface dataset:
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

Abstract
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

Abstract
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 : &gt;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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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)&gt;Cu(II)&gt;Zn(II)&gt;Cd(II)&gt;Ni(II)&gt;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.
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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.