bluuebunny/crossref_metadata_2025 huggingface dataset:
New Mesomorphic Compounds: N,N′,N″-Trialkanoyl-2,4,6-trimethyl-1,3,5-benzenetriamines
Authors: Harada Yukimasa , Matsunaga Yoshio
Published: July 2006

The homologous series of N,N′,N″-trialkanoyl-2,4,6-trimethyl-1,3,5-benzenetriamines has been prepared. The viscous birefringent melts are given by the butyryl to hexadecanoyl derivatives. The X-ray diffraction pattern recorded for the octanoyl derivative and the higher homologous members consists of two sharp inner peaks and a broad outer one assignable to the 100, 110, and 001 reflections respectively, indicating that the phase is hexagonal disordered columnar (Dhd). A more-structured high-temperature phase is displayed at lower temperatures by the nonanoyl to hexadecanoyl derivatives.
Some Aspects through Sedimentation Study on the Extremely Elongated Micelle Formed in Cationic Surfactant-Aromatic Additive Systems
Authors: Sakaiguchi Yuko , Hirata Hirotaka
Published: July 2006

Sedimentation studies were carried out upon systems composed of HTAB or HPB, a cationic surfactant, and several aromatic additives which were accompanied by remarkable viscoelasticity in a solution in which the existence of extremely elongated gigantic rod-like micelles was previously established by the authors as images under an electron microscope. Those elongated rod-like micelle systems appeared to be separated into two components: one showed floatation and the other sedimentation under a 6×104 rpm force field, providing rather pertinent values of S20ω in the order of 10−13s, compared with several proteins or other polymeric substances. After attaining an equilibrium state during sedimentation, the micellar particle weight was deduced to be about 1.2×107 amu. The obtained values seemed to be considerably smaller than those expected from the electron microscope images where the length of the rod-like micelles were assumed to be infinitely elongated. The discrepancy is likely to have been brought about by a degradation of the micelle chain under a strong centrifugal force field.
Catalytic Activity of Nonstoichiometric Niobium Oxide with Controlled Composition, NbO2.488–2.500, for Butene Isomerization
Authors: Murakami Yasushi , Wada Yuji , Morikawa Akira
Published: July 2006

The composition of niobium oxide was controlled between NbO2.488 and NbO2.500 by treating with mixture of water vapor and hydrogen gas at 873K. X-ray diffraction (XRD) study of the treated niobium oxide showed that only a phase of nonstoichiometric T-Nb2O5 was found in the range of NbO2.488–2.500 and a phase of NbO2 coexisted with the T-Nb2O5 phase by further reduction. The catalytic activity of the oxide for cis-2-butene isomerization had a maximum value at the O/Nb ratio of 2.494. The electron spin concentration of Nb4+ ion, and the amount of nitrogen monoxide adsorbed on the niobium oxide also showed a maximum value at the O/Nb ratio of 2.496 and 2.494, respectively. Coincidence in the dependences, on the composition of the reduced niobium oxide, of the catalytic activity, the spin concentration of Nb4+ ion, and of the amount of adsorbed nitrogen monoxide shows that isolated Nb4+ ion with unsaturated coordination is a catalytically active site.
Synthesis, Properties, and Crystal and Molecular Structure of Chloro[N,N-bis(2-hydroxyethyl)glycinato]copper(II)
Authors: Yamaguchi Hiromitsu , Nagase Makoto , Yukawa Yasuhiko , Inomata Yoshie , Takeuchi Toshio
Published: July 2006

The crystal and molecular structure of the title copper(II) complex was determined by the X-ray diffraction method. The crystal is orthorhombic with the space group Pbca, Z=8, a=14.18(1), b=15.835(7), c=8.188(3) Å. Full matrix least-squares refinements have led to a final R value of 0.047 for 2128 reflections. The copper atom is in a trigonal-bipyramidal geometry, ligated by a nitrogen atom, an oxygen atom of carboxylato group, two hydroxyl oxygen atoms and a chlorine atom. The complex has three five-membered chelate rings which are formed by one copper, one nitrogen, one oxygen, and two carbon atoms. There are two hydrogen bonds formed between the non-coordinated carboxylato oxygen atom and the hydroxyl hydrogen atom. The powder diffuse reflection spectrum of this complex exhibits a band characteristic of trigonal bipyramidal structure at 1000 nm. In the far-infrared absorption spectra of this complex, the bands at 340, 317, and 275 cm−1 are assigned to the stretching vibrations of Cu–N, Cu–Cl, and Cu–O (carboxylato), respectively.
Structures and Properties of Divalent Metal Complexes of an N2O2 Type Ligand, 6,6′-Bis(benzoylamino)-2,2′-bipyridine
Authors: Yamada Masaki , Araki Koji , Shiraishi Shinsaku
Published: July 2006

Complex formations of an N2O2 tetradentate ligand, 6,6′-bis(benzoylamino)-2,2′-bipyridine (babpH2) with various divalent metal ions were investigated. BabpH2 complexes of Ni(II), Co(II), and Zn(II) were obtained as dinitrate and/or diacetate, and their deprotonated complexes, [Ni(babp)], [Co(babp)], and [Zn(babp)], where babp represents the deprotonated form of amide protons of babpH2, were also isolated. The deprotonated complexes were shown to have high thermal stability up to 300 °C. The structures, stabilities, and spectral properties of these complexes were discussed in relation to the copper(II) complexes of babpH2 and babp.
Determination of Trace Metals in Seawater by Graphite Furnace Atomic Absorption Spectrometry after Preconcentration Using Synergistic Extraction
Authors: Ueda Kazumasa , Kubo Katsutoshi , Yoshimura Osamu , Yamamoto Yoshikazu
Published: July 2006

Trace Cd, Mn, Pb, Co, Ni, and Cu have been quantitatively separated and concentrated from seawater matrices with a low concentration (mmol dm−3 level) of 1,1,1-trifluoro-4-mercapto-4-(2-thienyl)-3-buten-2-one and trioctylphosphine oxide cyclohexane solution. The synergistic extract was directly injected into the furnace and a reproducible signal with little memory effect was obtained. The extracted adduct enhanced the AAS sensitivity during thermal decomposition processes, and simultaneously resulted in depression of the interferences. The detection limits of the analytes ranged from several ng dm−3 to 100 ng dm−3. The proposed technique provides both the preconcentration and determination for trace analysis by a single extraction using a small volume of sample. Coastal seawater samples were analyzed by the method.
The Crystal and Molecular Structures of Dithia[4.3](6,9)(6′,9′)purinophane, Dithia[4.4](6,9)(6′,9′)purinophane, and Dithia[3.3](6,9)(9′,6′)purinophane
Authors: Seyama Fumio , Sakata Yoshiteru , Kasai Nobutami , Misumi Soichi
Published: July 2006

Molecular structures of three purinophanes, dithia[4.3](6,9)(6′,9′)purinophane (1), dithia[4.4](6,9)(6′,9′)purinophane (2), and dithia[3.3](6,9)(9′,6′)purinophane (3), have been determined by means of X-ray diffraction. 1: monoclinic, space group P21/n, a=10.561(1), b=16.674(3), c=9.136(1) Å, β=90.29(1)°, V=1608.8(4) Å3, Dc=1.529 g cm−3 for Z=4. 2: monoclinic, space group P21⁄n, a=10.870(2), b=17.058(2), c=9,289(1) Å, β=94.15(1)°, V=1717.9(4) Å3, Dc=1.487 g cm−3 for Z=4. 3: monoclinic, space group P21/n, a=8.068(1), b=27.841(2), c=6.913(1) Å, β=111.0(1)°, V=1449.8(2) Å3, Dc=1.631 g cm−3 for Z=4. All structures were solved by the direct method, and refined anisotropically by the least-squares procedure. Final R values are 0.045, 0.053, and 0.050 for 1, 2, and 3, respectively. Molecular structures of 1 and 2 take very similar crossed form, whereas that of 3 reveals a different crossed form.
A Novel Synthesis of (±)-Prostaglandin B1 Methyl Ester
Authors: Naora Hirokazu , Ohnuki Takashi , Nakamura Asao
Published: July 2006

Five simple preparative methods of (±)-prostaglandin B1 (PGB1) methyl ester are described. All routes were started from a common intermediate, 7-(2-hydroxy-5-oxo-1-cyclopentenyl)heptanoic acid derived from cyclooctanone via two steps. The key reaction of these routes is a palladium-catalyzed vinylation. The methods provided other PGB1 congeners and are applicable to synthesize 11-functionalized PG systems.
Direct Synthesis of Ethylene Glycol from Carbon Monoxide and Hydrogen by Use of Rhodium Catalyst. The Effect of Amine Promoters and Their Roles
Authors: Masuda Takashi , Murata Kazuhisa , Matsuda Akio
Published: July 2006

The influence of addition of amines on the direct synthesis of ethylene glycol (EG) has been investigated using a rhodium catalyst under a high pressure (1800 kg cm−2). The addition of amines improved the catalyst activity and selectivity for the EG formation and the stability of the catalyst. The addition of amines further resulted in glycerol (GL) formation. Optimum amine/rhodium ratios for the EG formation were 50–100 in tetrahydrofuran solvent with a low polarity and 1–3 in γ-butyrolactone solvent with a high polarity. Optimum N/Rh ratios and IR spectra of reaction solutions suggested that amine promoters serve to accelerate the formation of mononuclear Rh species from the catalyst precursor. It was also suggested that amines promote formation of a Rh–CH2OH complex and insertion of CO. Bulky amines such as triisobutylamine, N-ethylcarbazole, triisopropanolamine, and tribenzylamine were especially effective promoters for the formation of EG and GL. The effectiveness of bulky amines as the promoter is discussed.
NMR Spectra of Organogermanium Compounds. VI. NMR Spectra and Molecular Mechanics Calculations of 3-Methyl- and 3,3-Dimethylgermacyclohexanes
Authors: Takeuchi Yoshito , Ichikawa Yasuko , Tanaka Katsumi , Kakimoto Norihiro
Published: July 2006

Several 3-methyl- or 3,3-dimethylgermacyclohexanes were prepared and their 13C and 73Ge NMR spectra were determined. Steric energies for all of stereoisomers of some of these germacyclohexanes were calculated by MM2 program. The effect of axial 3-methyl group of germacyclohexanes upon its C-5 is much the same with the corresponding effect in cyclohexanes, and is much smaller than the effect caused by axial methyl on germanium upon C-3,5. A large upfield shift is recorded for germanium nuclei when there is an axial methyl on C-3 of germacyclohexanes.
Formation of 4-Benzamidoisoxazole Derivatives
Authors: Zen Shonosuke , Harada Kazuho , Nakamura Hikaru , Iitaka Yoichi
Published: July 2006

The titled compounds (3) were synthesized by the reaction of nitrile oxides with 1-azirines and also the reaction of aliphatic nitro compounds with dibenzoylmethane derivatives in the presence of acetyl chloride and sodium methoxide. The structure of 3 was established by single crystal X-ray analysis. A mechanism of the formation for 3 is proposed.
The Reaction of 1-Amino-2,3-diphenylcyclopropenium Ions with 1,3-Diketones to Afford 2,4-Cyclopentadien-1-ols: The Regioselective Ring-Opening of 1-Aminocyclopropene Intermediates
Authors: Yoshida Hiroshi , Tamai Tomoji , Ogata Tsuyoshi , Matsumoto Kiyoshi
Published: July 2006

1-Amino-2,3-diphenylcyclopropenium tetrafluoroborates (4) reacted with cyclic or acyclic 1,3-dicarbonyl derivatives (5) such as 1,3-diketones, β-keto esters, or gem-diesters in the presence of triethylamine to give 2,4-cyclopentadien-1-ols in moderate to good yields. Some isolated cyclopropene intermediates were, upon heating, converted to the corresponding cyclopentadienols. The factors that influence on the reactivities of 4 and 5 (basicities of the amino groups of 4 and bulkiness of the substituents of 4 and 5) are discussed qualitatively.
Radical Transport Reaction. Concurrent Transfer of Electron and Proton
Authors: Ichikawa Junji , Sonoda Takaaki , Kobayashi Hiroshi
Published: July 2006

Concurrent transport of electron and proton on the same molecule; formal hydrogen-transfer reaction, is successfully realized in aprotic media by using 1-butyl-4,4′-bipyridinium cation radical (BuPPH\underset.+), which is prepared from 1-butyl-4-(4-pyridyl)pyridinium ion. Hydrogen reduction with BuPPH\underset.+ was discriminated from electron reduction with octylviologen cation radical by the chemoselective reduction preferring enedione to vic-dibromide in aprotic media.
Effects of Crown-Type Host–Guest Complexation on Electrochemical Profiles of Pb2+ Ion
Authors: Tsukube Hiroshi , Takagi Kentaro , Higashiyama Tatsuo , Iwachido Tadashi , Hayama Naomi
Published: July 2006

Crown ethers, cryptands, and related synthetic host molecules modified electrochemical profiles of Pb2+ ion by host–guest complexations. The reduction potentials of the Pb2+ complexes were significantly correlated with their complex stabilities.
Electron Spin Resonance Studies of Anion Radicals of Benzoylsilanes
Authors: Mochida Kunio , Yamamoto Keiji
Published: July 2006

ESR studies of anion radicals of seven substituted benzoylsilanes were investigated. ESR data of these anion radicals are discussed in comparison with those of aryl alkyl ketones. ESR spectra of secondary product derived from the anion radical of benzoylsilanes were also examined.
Partial Oxidation of Isobutene to Methacrylic Acid on V2O5–P2O5 Catalysts
Authors: Ai Mamoru
Published: July 2006

The vapor-phase air oxidation of isobutene was studied with V2O5, V2O5–TiO2, V2O5–MoO3, V2O5–P2O5, V2O5–P2O5–TeO2, and heteropoly compound catalysts, such as H3PMo12O40, Cs2HPMo12O40, H5PMo10V2O40, and Cs2.5H2.5PMo10V2O40, in the presence of water vapor. On pure V2O5, the oxidation products were acetic acid and carbon oxides, plus small amounts of acetone and methacrylaldehyde. With the addition of TiO2 to V2O5, the selectivity to acetic acid increased a little, but the formation of methacrylaldehyde disappeared. The addition of MoO3 to V2O5 enhanced the formations of acetone and methacrylaldehyde, to a certain extent, but methacrylic acid was not obtained. With the V2O5–P2O5 catalysts, the yield of methacrylic acid attained 21 mol%, the sum of the yields of methacrylaldehyde and methacrylic acid attained 30 mol%, and the yield of acetic acid attained also 30 mol%. The P/V atomic ratio=1.6 catalyst was better than the P/V=1.06 catalyst in the formation of methacrylic acid. Further, the performance of the P/V=1.6 catalyst was better than that of the heteropoly compound catalysts. The results were discussed in the light of the acid–base properties of the catalysts.
The CH-Surface Area of Sugar Molecules as a Measure of Their Potential Hydrophobicity
Authors: Yano Yuki , Tanaka Keiko , Doi Yukio , Janado Masanobu
Published: July 2006

Differential affinity of three groups of sugars (monosaccharides, glucodisaccharides and methyl glycosides) can reasonably be interpreted in terms of a molecular surface parameter, the ratio of the surface area of hydrophobic groups (CH, CH2, and CH3) to that of hydrophilic groups (OH and –O–) computed from the crystallographic data.
Solvatochromism of the Co(III) Complexes with Macrocyclic N3O3-Type Ligands
Authors: Fujiwara Mika , Yoshitake Michiko , Fukuda Yutaka , Sone Kozo
Published: July 2006

The color and visible spectrum of [Co(tacnta)] and [Co(tacntp)]·3H2O depend remarkably on the acceptor number of the solvent, as also do those of K[Co(edta)]·2H2O and related chelates. The changes are especially large in the case of [Co(tacntp)]·3H2O, extending to solvents of high acidity. A plausible explanation is given for this solvatochromism.
Pheophytinization of Chlorophyll a and Chlorophyll a′ in Aqueous Acetone
Authors: Mazaki Hitoshi , Watanabe Tadashi
Published: July 2006

Chlorophyll (Chl) a and its C-10 epimer, Chl a′, are compared for pheophytinization (demetallation) kinetics in aqueous acetone containing HCl. For each pigment the pheophytinization rate is of second order with respect to proton, and under identical conditions Chl a′ is pheophytinized by roughly 50% faster than Chl a, due probably to weaker Mg–N bonds in Chl a′.
Sesquiterpene Lactones from Flowers of Picris hieracioides L
Authors: Kanayama Takeshi , Tada Masahiro
Published: July 2006

The isolation and structural elucidation of four guaianolides from the antimicrobial fractions of the flowers of Picris hieracioides L. (Compositae) are reported. Two of them are new compounds.
One-Step Conversion of Mesoionic Olate to Thiolate by Lawesson’s Reagent
Authors: Araki Shuki , Goto Tetsuya , Butsugan Yasuo
Published: July 2006

Treatment of mesoionic olates with Lawesson’s reagent provides a convenient one-step conversion to mesoionic thiolates.
1,3,4-Thiadiazolines by a 1,5-Dipolar Ring Reconstruction of Mesoionic (2,3-Diphenyltetrazolio)thio Ylides
Authors: Araki Shuki , Goto Tetsuya , Butsugan Yasuo
Published: July 2006

4-Phenyl-2-phenylazo-2,3-dihydro-1,3,4-thiadiazoles were synthesized from 2,3-diphenyltetrazolium-5-thiolate by two methods. The formation of the thiadiazolines is rationalized by 1,5-dipolar ring closure of the intermediate mesoionic (tetrazolio)thio ylides.
Preparation and Resolution of Bis[tris(2-aminoethaneselenolato)cobalt(III)-μ-Se, μ-Se′, μ-Se″]cobalt(III) Complex
Authors: Miyanowaki Shin , Konno Takumi , Okamoto Ken-ichi , Hidaka Jinsai
Published: July 2006

The title Se-bridged complex, [CoIII{CoIII(aese)3}2]3+ (aese=2-aminoethaneselenolate), was newly prepared by the reaction of fac-[Co(aese)3] with Co2+ and separated into three isomers, ΔΔ, ΔΛ, and ΛΛ, by the ion-exchange chromatographic method. The isomers were characterized from their absorption, CD, and 13C NMR spectra.
Ylide-Metal Complexes. XIV. An X-Ray Photoelectron Spectroscopic Study on Tellurium Complexes of Methylenetriphenylphosphorane
Authors: Konno Hidetaka , Yamamoto Yoshihisa
Published: July 2006

A series of new tellurium complexes of methylenetriphenylphosphorane, (C6H5)3P=CH2 (L), namely, dichlorobis(methylenetriphenylphosphorane)tellurium dichloride, [L2TeCl2]Cl2, chlorotris(methylenetriphenylphosphorane)tellurium trichloride, [L3TeCl]Cl3, and tetrakis(methylenetriphenylphosphorane)tellurium tetrachloride, [L4Te]Cl4, were examined by XPS. Binding energies of Te 3d electrons for the complexes are considerably lower than those for common Te(IV) compounds such as (C6H5)2TeCl2, TeCl4 (correctly Te4Cl16) and others, and they diminished with increasing number of L’s and decreasing number of bonded chlorine atoms, indicating that L is an electron donor. Bonded chlorine atoms and free chloride ions were clearly distinguished from the binding energy of Cl 2p3⁄2 electrons.
Determination of Iodide Ion Using Alkali-Free Lead Phosphate Glasses as Potentiometric Detector Sensors in Nonsuppressed Ion Chromatography
Authors: Nomura Tsuyoshi , Hikichi Yasuo , Nakagawa Genkichi
Published: July 2006

Alkali-free lead phosphate glasses containing silver oxide show a linear relationship with the Nernstian slope for iodide concentration. By using these glass membranes as potentiometric detector sensors for ion chromatography, the limit of detection for iodide ion was extended down to 0.05 μg cm−3. The high sensitivity can be interpreted in terms of the strong interaction between iodide ion and the silver ion incorporated in the membrane material.
Yeast-Mediated Reduction of N-Substituted Acetoacetamides. Improvement of Conversion by Immobilization
Authors: Kawai Masao , Tajima Kenji , Mizuno Satoko , Niimi Koichi , Sugioka Hiroaki , Butsugan Yasuo , Kozawa Akimasa , Asano Tsuneo , Imai Yoshio
Published: July 2006

N-Ethylacetoacetamide and acetoacetanilide were enantioselectively converted into the corresponding (S)-3-hydroxy compounds by alginate- or polyurethaneimmobilized bakers’ yeasts, while without immobilization the yield of the yeast-mediated reaction was very low.
Catalytic Oxygenation of Cholesterol with a Platinum Catalyst under Moderate Pressure of Oxygen
Authors: Sakamaki Hiroshi , Take Masa-aki , Akihisa Toshihiro , Matsumoto Taro , Ichinohe Yoshiyuki
Published: July 2006

The catalytic oxygenation of cholesterol 1 with a platinum black catalyst under moderate pressure (20–25 atm) of oxygen yielded eleven oxidation products, 3–13a. The reaction pathway of the catalytic oxygenation is discussed on the basis of the results for several reaction conditions.
Synthesis of 1,4-Benzoquinone Derivatives Having Two Side-Armed Polyethers and Crown Ethers, and Their Electrochemical Study in the Presence of Alkali Metal Cations (Na+ and K+)
Authors: Togo Hideo , Hashimoto Kiichi , Morihashi Kenji , Kikuchi Osamu
Published: July 2006

Several crown ethers and two side-armed polyethers which have reducible quinonoid groups were prepared. Some of them, 7a, 7b, and 7d, showed highly enhanced cation-binding properties for the Na+ cation upon electrochemical reduction.
A Facile Syntehsis of 2-Substituted Azetidines
Authors: Shono Tatsuya , Matsumura Yoshihiro , Uchida Kenshi , Nakatani Fumihiko
Published: July 2006

A new method for the synthesis of 2-substituted azetidines has been exploited. The method consists of (1) anodic acetoxylation of 1-(p-tolylsulfonyl)azetidine at the 2-position and (2) subsequent nucleophilic substitution of the acetoxyl group with nucleophiles such as trimethylsilyl cyanide, allyltrimethylsilane, 2-acetoxyfuran, and trimethyl phosphite.
Molecular Structure of Trimethylphosphine–Borane as Determined from Electron Diffraction and Microwave Spectroscopic Data
Authors: Iijima Kinya , Hakamata Yumi , Nishikawa Takashi , Shibata Shuzo
Published: July 2006

The molecular structure of trimethylphosphine–borane has been determined from gas electron diffraction and spectroscopic data. The molecular parameters and their uncertainties are rg(B–H)=1.225±0.011 Å, rg(P–B)=1.899±0.006 Å, rg(C–P)=1.815±0.003 Å, rg(C–H)=1.103±0.002 Å, ∠HBH=108.6±0.6°, and ∠CPC=104.6±0.3°. The P–B distance of this complex is about 0.04 Å shorter than those of trimethylphosphine–boron trihalides.
17O NMR Study of Metal Carbonyl Cluster Compounds. III. 17O NMR Spectra of Mixed Metal Carbonyl Cluster Compounds, R2Sn[M(CO)x][M′(CO)y], R2Sn[M(CO)x][M′(CO)yCp], and ClSn[Mn(CO)5][Fe(CO)2Cp]2
Authors: Onaka Satoru , Kato Yoshio
Published: July 2006

A series of mixed metal carbonyl cluster compounds of R2Sn[M(CO)x][M′(CO)y] and R2Sn[M(CO)x][M′(CO)yCp] were synthesized and their 17O NMR spectra were measured to demonstrate how 17O NMR spectroscopy is superior to IR spectroscopy to study the electronic nature of the oxygen atoms in CO groups. For these mixed metal clusters, 17O NMR spectral assignments were easily made and the electron distribution around the O atoms was concluded to be only slightly changed compared with those of homo-dinuclear R2Sn[M(CO)x]2 and R2Sn[M′(CO)yCp]2.
New Mesomorphic Compounds: N,N′-Dialkanoyl-2,4-bis(alkanoyloxy)-1,3-benzenediamines
Authors: Kawada Hiromitsu , Matsunaga Yoshio
Published: July 2006

A series of N,N′-dialkanoyl-2,4-bis(alkanoyloxy)-1,3-benzenediamines has been synthesized. The high temperature phases appearing in the heptanoyl to hexadecanoyl derivatives are viscous and are transformed into isotropic liquids with enthalpy changes of 20 kJ mol−1 or less. Their X-ray diffraction patterns are characteristic of the hexagonal disordered columnar phase. The second moment of the broad-line proton NMR spectrum measured in the mesophase region is 0.8 to 0.9 G2 in the case of the octanoyl derivative and 0.04 G2 in the case of the tetradecanoyl derivative, indicating the rather large difference in the motional behavior between these half-disk-shaped molecules.
Electrode Kinetics of Metal Complexes Confined in Perfluoro Polycarboxylate and Polysulfonate Coatings on Graphite Electrodes
Authors: Oyama Noboru , Ohsaka Takeo , Ushirogouchi Tooru , Sanpei Sachiko , Nakamura Sadako
Published: July 2006

A heterogeneous electron-transfer process of [Os(bpy)3]2+⁄3+ (bpy: 2,2′-bipyridine) and [(trimethylammonio)methyl]ferrocene/ferricinium (TAF+⁄2+) redox couples, which were confined in perfluoro polycarboxylate and polysulfonate polyelectrolyte coatings on graphite electrodes, at the electrode/film interfaces as well as a homogeneous charge-transport process within the coating films were examined by means of potential-step chronoamperometry and chronocoulometry, normal pulse voltammetry and ac impedance measurements. The relevant kinetic parameters (i.e., the standard rate constant k° and the transfer coefficient of the heterogeneous electron-transfer process and the apparent diffusion coefficient Dapp for the homogeneous charge-transport process) were determined at various concentrations of the redox species in the films at various pH’s. The temperature dependences of Dapp, k° and the formal potentials of the [Os(bpy)3]2+⁄3+ and TAF+⁄2+ couples confined in the films were also examined and the relevant activation parameters for the heterogeneous electron-transfer and homogeneous charge-transport processes and the reaction entropies of these redox couples were evaluated. On the basis of the kinetic and thermodynamic data obtained, the mechanism of the charge-transport process within the films, the effects of polymer domain and pH on the rates of the heterogeneous electron-transfer and homogeneous charge-transport processes and on the incorporation of the redox species into the films, etc. are discussed.
The α-Helical Conformation of the Aib-Containing Oligopeptide, Boc–(Leu3–Aib)2–OBzl
Authors: Okuyama Kenji , Tanaka Nobuo , Doi Masamitsu , Narita Mitsuaki
Published: July 2006

The octapeptide Boc–(Leu3–Aib)2–OBzl crystallizes in the space group P21, with a=11.450(2), b=27.915(7), c=11.255(2) Å, β=116.95(1)°, and Z=2. The crystal structure has been solved by direct methods and refined to an R value of 0.08. The peptide back-bone, except for the C-terminal Aib residue, folds into a right-handed α-helical conformation, stabilized by four intramolecular (5→1) hydrogen bonds and two intermolecular hydrogen bonds between molecules related by the 21 symmetry along the b direction. In order to determine the helical conformation definitively, the helical parameters (unit height h and unit twist θ) at each amino-acid residue were derived from the bond lengths, bond angles, and torsional angles of the peptide main chain. The average values of these parameters for seven residues (h=1.57 Å and θ=99.0°) showed much better agreement with those for an α-helix (h=1.5 Å and θ=100°) rather than with those for a 310-helix (h=2.0 Å and θ=120°). Peptide helices are arranged in columns in head-to-tail fashion. These columns are packed in parallel with respect to their helical direction. Between neighbouring chains of helices only hydrophobic contacts are found.
Biomolecules Conform to the Rule of Topological Charge Stabilization
Authors: Aihara Jun-ichi
Published: July 2006

Almost all biomolecules conform to the rule of topological charge stabilization. Heteroatoms are placed at the right sites in proteins, nucleoside bases, porphyrins, and related metabolites. It is noteworthy that typical redox-mediating coenzymes obey this rule both in the oxidized and reduced states. Thus, it is very likely that the rule of topological charge stabilization has been one of the most important guiding principles not only in chemical evolution but also in general biosynthesis.
The Infrared Spectrum of Dioxygen Bound to the Synthetic Porphinatoiron in an Aqueous Medium
Authors: Yuasa Makoto , Yamamoto Kimiko , Nishide Hiroyuki , Tsuchida Eishun
Published: July 2006

A highly concentrated aqueous solution of heme ([heme]=25 mM) was prepared by embedding the 5,10,15,20-tetrakis(α,α,α,α-o-(2′,2′-dimethyl-20′-(2″-trimethylammonio)ethylphosphonatoxy)eicosanamido)phenyl)porphinatoiron(II) complex of 1-dodecylimidazole in bilayer of polymerized 1,2-bis(2,4-octadecadienoyl)-sn-glycero-3-phosphocholine liposome (poly-lipid liposome/heme). The dioxygen-binding mode of the poly-lipid liposome/oxyheme in the aqueous medium was then measured by means of infrared difference spectroscopy: The νo–o value at 1161 cm−1 was found to correspond to those of the oxy picket-fence heme in Nujol mulls, oxy myoglobin, and oxy hemoglobin in an aqueous medium.
Ab Initio Calculation for the Interaction Energy of He–H
Authors: Ichihara Akira , Sasagane Kohtoku , Itoh Reikichi
Published: July 2006

Using the help of an ab initio calculation with a configuration interaction (CI) treatment, the potential energies of a HeH system in the ground (X2Σ+) and the first three (A2Σ+, B2Π, C2Σ+) excited electronic states were calculated, making due correction for the basis set superposition effect.
Geometrical Isomers of Anionic Complexes Favorable to Chiral Discriminatory Ion-Pairing with Λ-[Co(en)3]3+ Ion and the Diastereomeric Ion-Pair Formation Constants in Solution
Authors: Tatehata Akira , Asaba Yasuyuki
Published: July 2006

The stereoselectivities in the ion pairing of the geometrical isomers of anionic complexes, [Co(ox)(gly)2]− and [Co(ox)(edda)]− (ox=oxalate dianion, gly=glycinate anion, and edda=ethylenediamine-N,N′-diacetate dianion) with [Co(en)3]3+ have been investigated by a chromatographic method. Only the C1-cis(N) isomer of three geometrical isomers of [Co(ox)(gly)2]− and the β-cis isomer of two of [Co(ox)(edda)]−, in which three coordinated oxygen atoms are disposed triangularly along the pseudo C3 axis, have been observed to interact more strongly with [Co(en)3]3+ than the other geometrical isomers. The diastereomeric ion-pair formation constants of C1-cis(N)-[Co(ox)(gly)2]− and β-cis-[Co(ox)(edda)]− with [Co(en)3]3+ in solution have been determined by a conductance method at 25 °C. The results were consistent with those of the chromatographic studies. An enhancement of the circular dichroism (CD) intensity of the A2 component at the first d–d transition region of [Co(en)3]3+ has been observed upon the formation of ion pairing between the complex ions. Therefore, a favorable ion pair is considered to involve the hydrogen bonds between the coordinated oxygen atoms of the anionic complexes and the three N–H protons of [Co(en)3]3+ along the C3 axis.
Cobalt(III) Complexes with Quadridentate Ligands. VII. The Preparation and Properties of the Salicylato or Dichloro[tris(2-aminoethyl)amine]cobalt(III) Complexes and the Related Complexes
Authors: Toyota Eiko , Yamamoto Yutaka , Yamamoto Yoshihisa
Published: July 2006

Salicylato- or 3-methyl(or 4-methyl)salicylato[tris(2-aminoethyl)amine]cobalt(III) complexes, [Co(R-sal)tren]Cl·nH2O (R: H, CH3) have been prepared from a reaction mixture of dichloro[tris(2-aminoethyl)amine]cobalt(III) chloride hydrate, [CoCl2(tren)]Cl·H2O, Ag2O, and salicylic acid or 3-methyl- or 4-methylsalicylic acid. Two geometrical isomers (t- and p-) of their complexes were separated by Dowex 50W-X2 column chromatography. Their t- and p-isomers have been established by their 1H NMR and absorption spectra. The formation ratio of t- and p-isomers is ca. 3:1. The isomerization between t-isomer and p-isomer was not observed in water and methanol. In the absorption spectra, the first absorption band for the t- and p-isomers was observed at 535 nm and 515 nm, respectively. In the 1H and 13C NMR spectra of [CoCl2(tren)]Cl·H2O, the signals of the tertiary amine, (Remark: Graphics omitted.), side methylene protons and methylene carbons have been assigned to the individual methylene protons and methylene carbons of the coordinated tris(2-aminoethyl)amine ligand.
Voltammetric Study of Organic Metals. I. The Determination of the Electrochemical Conditions for Crystal Growth
Authors: Sakura Sachiko , Imai Hideo , Anzai Hiroyuki , Moriya Tetsuo
Published: July 2006

The metallic crystals of organic charge-transfer complexes are grown by means of the electrolytic oxidation of tetrathiafulvalene (TTF) derivatives in the presence of trihalide anions in organic solvents. In order to obtain a crystal of good quality, the optimal conditions for the growth have been searched for based on the data on the cyclic voltammetry. In this paper, the electrochemical conditions, such as the oxidation potential, the stability of the donor monocation radicals, and the redox behavior of the anions under the oxidation potential of the donors, are discussed in relation to the chemical reactions proceeding in the solution during the crystal growth.
Olefin Epoxidation Catalyzed by Sterically Bulky Metalloporphyrins (Metal=Fe,Mn) by Use of Sodium Hypochlorite as an Oxygen Source—A Kinetic Study
Authors: Amatsu Hiroyuki , Miyamoto T Ken , Sasaki Yukiyoshi
Published: July 2006

Substituents around an active center give a variety of effects on metalloporphyrin catalyses. In order to examine the effects of a substituent on the kinetic parameters, several olefins (styrene derivatives, cyclooctene and 1-octene) have been epoxidized by iron(III) and manganese(III) complexes of meso-tetrakis(2,6-dimethylphenyl)porphyrin or meso-tetrakis(2,6-dichlorophenyl)porphyrin in the presence of sodium hypochrolite as an oxidant. As previously reported for a manganese porphyrin system, the rate-profile of an iron complex can be described by the Michaelis–Menten equation. Several examples of an anomalous rate dependence on the olefin concentration have been observed. The ortho substituents have little influence on the binding affinity of the oxo–iron complex to olefin, in contrast to the case of manganese complexes. It is additionally proposed that the N-alkylation of an iron porphyrin has some correlation to the kinetic parameters.
Asymmetric Reduction of α-(Dimethylthiocarbamoylthio) Carbonyl Compounds with Bakers’ Yeast
Authors: Tsuboi Sadao , Kohara Noriyuki , Doi Katsumi , Utaka Masanori , Takeda Akira
Published: July 2006

Treatment of α-(dimethylthiocarbamoylthio) ketones with bakers’ yeast afforded the corresponding chiral alcohols in high yields with high enantiomeric excess (in most cases, more than 96% ee). α-(Dimethylthiocarbamoylthio) aldehydes were reduced to give chiral α-(dimethylthiocarbamoylthio) alcohols in 69–92% yields with 32–63% ee, which were converted to chiral 1,2-epithio derivatives.
Phosphonylation of Biomolecules with Inorganic Diphosphonate. II. Phosphonylation of Phosphate Groups on Nudeoside 5′-Monophosphates, Deoxynudeoside 5′-Monophosphates, and Sugar Phosphates
Authors: Yamamoto Yoshisuke , Baba Yoshinobu , Mizokuchi Miwa , Onoe Mika , Sumiyama Tomoko , Tsuhako Mitsutomo , Yoza Norimasa , Ohashi Shigeru
Published: July 2006

Inorganic diphosphonate phosphonylated predominantly phosphate groups on nucleoside 5′-monophosphates (=NMP’s: AMP, GMP, IMP, CMP, and UMP), deoxynudeoside 5′-monophosphates (=dNMP’s: dAMP and dTMP), and sugar phosphates (=SP’s: GlclP, Glc6P, and Rib5P) in aqueous solutions under mild conditions (50–70 °C, pH 6). The chemical structures of phosphonylated products were discussed on their 31P NMR spectra and high-performance liquid chromatograms. The main phosphonylated products from NMP’s and dNMP’s were analogous in structure to nucleoside 5′-diphosphates. The rate of phosphonylation of phosphate groups on NMP’s, dNMP’s, and SP’s varied strongly depending on reaction conditions: pH, reaction temperature, and initial concentration of inorganic diphosphonate. The maximum yields of phosphonylated products were ca. 70% for all NMP’s, dNMP’s, and SP’s under the following conditions: initial concentration of inorganic diphosphonate is 1.5 mol dm−3; each initial concentration of NMP’s, dNMP’s, or SP’s is 0.1 mol dm−3; 70 °C; pH 6.
Reactivities of Stable Rotamers. XXII. Lewis Acid-Catalyzed Reactions of 3-(1,4-Disubstituted 9-Triptycyl)-3-methylbutanoyl Chloride: Isolation of Rotameric Ketones and Competition between Cyclizations to Substituted and to Unsubstituted Benzene Rings
Authors: Tanaka Toshimasa , Yonemoto Katsumi , Nakai Yasufumi , Yamamoto Gaku , Oki Michinori
Published: July 2006

Rotational isomers of 3-(1,4-disubstituted 9-triptycyl)-3-methylbutanoic acid, where the substituent is either a methoxyl or a methyl, have been prepared, starting from 1,4-disubstituted 9-(1,1-dimethyl-3-butenyl)triptycene. Lewis acid-catalyzed reactions of the ap-acid chloride afforded corresponding ketones expected from the intramolecular Friedel–Crafts reaction. The sc form of the 1,4-dimethoxy compound gave a ketone that was formed by the reaction of the unsubstituted benzene ring and a lactone which was derived by the attack of the acylium ion on the methoxy-oxygen followed by demethylation. The sc form of the 1,4-dimethyl compound afforded a ketone which was expected from cyclization to the unsubstituted benzene ring and another ketone that was derived from the ipso attack of the acylium ion followed by 1,2-methide migration. In both cases, the ketone derived from the ap form of the acid chloride was different from that obtained from the sc. The barriers to isomerization of the ap-ketone to the sc-ketone was 29.6 kcal mol−1 at 100.5 °C and 25.6 kcal mol−1 at 56.0 °C for the methoxy and the methyl compounds, respectively. In both cases, the ketone derived from the sc-form was more stable than that from the ap, the sc/ap ratio at the equilibrium being 20.0 (56.0 °C) and 5.9 (100.5 °C), respectively, for the methyl and the methoxy compounds. In the reaction of the sc form, the competitive results between the cyclization toward the unsubstituted benzene ring and that toward the substituted vary according to the solvent and the Lewis acid used.
Asymmetric Synthesis of Axially Chiral, Unsymmetrical Diphenic Acids via Intramolecular Ullmann Coupling Reaction
Authors: Miyano Sotaro , Fukushima Hiroshi , Handa Shigeru , Ito Hiromitsu , Hashimoto Harukichi
Published: July 2006

A practical route to unsymmetrical diphenic acids is described. Successive esterification of ethylene glycol with two different 2-halobenzoyl chlorides gave the corresponding mixed diester, which was treated with copper powder in boiling DMF under dilution conditions. Silica-gel column chromatography allowed ready separation of the intramolecularly coupled cyclic diester (30–60% yield) from other by-products accompanying the Ullmann reaction, and alkaline hydrolysis gave unsymmetrical diphenic acid. Axially chiral, unsymmetrical diphenic acids of more than 99% enantiomeric excess were obtained from the reaction of mixed diesters prepared from (R)-1,1′-bi-2-naphthol.
Dehydrooligopeptides. X. Useful Synthetic Method for (E)- and (Z)-Isomers of Dehydroaspartic Acids, and Their Δ1,2-Dehydrodipeptides by the Base-Catalyzed β-Elimination
Authors: Shin Chung-gi , Obara Takumi , Morita Shigeru , Yonezawa Yasuchika
Published: July 2006

Various kinds of N-benzyloxycarbonyl (E)- and (Z)-dehydroaspartic acid (Cbz–ΔAsp) derivatives were successfully synthesized by both a base-catalyzed β-elimination of β-hydroxyaspartic acid esters (HyAsp) via their β-mesyloxy Asp derivatives and several modes of the cleavages of α-(N-Cbz)-aminomaleic acid anhydride. Moreover, for high-yield synthesis of Δ1,2-dehydrodipeptides (DHP) containing a ΔAsp residue, a similar β-elimination was applied to Δ1-DHP with a C-terminal HyAsp residue. The configuration of all the new ΔAsp derivatives and their Δ1,2-DHPs were confirmed mainly on the basis of 1H NMR spectral data.
Determination of Ionic Partial Molar Volumes of Bolaform Electrolytes by Means of Sedimentation Potential Measurements
Authors: Hirakawa Hiromitsu , Nomura Hiroyasu , Kawaizumi Fumio
Published: July 2006

Sedimentation potentials (SP) and electrical conductivities have been measured in aqueous solutions of three kinds of bolaform electrolytes, [R3N–(CH2)n–NR3]Br2 where R stands for ethyl group and n is equal to 4, 6, and 10. Using the SP and conductivity data the partial molar volumes of the bolaform salts were divided into cationic and anionic parts. Two ionic sites of the bolaform electrolytes behave independently.
Vapor Pressures of Diethyl, Diisopropyl, and Dibutyl Phthalates at Reduced Pressures
Authors: Katayama Hirotake
Published: July 2006

Vapor pressures of the three phthalates noted above were measured over the ranges 0.3–30, 0.3–10, and 0.3–9 kPa, respectively. The correlations of vapor pressures using the Cragoe equation with 4 constants give the percent root mean square deviations of 0.21, 0.33, and 0.28, respectively.
The Preparation and Properties of an Enzyme Electrode for Creatine
Authors: Motonaka Junko , Takabayashi Hisaaki , Ikeda Sanae , Tanaka Nobuyuki
Published: July 2006

An enzyme electrode for creatine consisting of a single glass electrode and immobilized creatine kinase was prepared, and the effects of various conditions on the calibration curve obtained with this electrode were examined. Creatine in the range of 0.42–3.3 mmol dm−3 could be determined at 37 °C and pH 9.
Synthesis, and Crystal and Molecular Structure of Bis(benzylamine)bis(thiocyanato)cadmium(II), [Cd(SCN)2(C6H5CH2NH2)2], in Planar Polymeric Form: Allotrope of the Linear Polymeric Complex
Authors: Ouchi Akira , Taniguchi Masahiro
Published: July 2006

The title complex (1), which is two-dimensional polymeric and an allotrope of the previously reported linear polymeric complex (2), was obtained and its crystal and molecular structure was determined by means of a single-crystal X-ray diffraction method. Since 1 is more soluble in organic solvents, 1 and 2 could be prepared, separately. The crystal of CdC16H18N4S2, F. W. 442.9, is monoclinic, space group P21⁄c, a=13.958(2), b=5.759(1), c=11.466(2) Å, β=99.24(1)°, U=909.8(3) Å3, Z=2, Dm=1.61(3), Dx=1.62 g cm−3, μ(Mo Kα)=14.2 cm−1. The cadmium atom is in a trans-2S4N-hexa-coordinated octahedral geometry. Each cadmium atom is at the center of symmetry, and it is bridged to four cadmium atoms by an thiocyanate ion, respectively, and the complex network is extended on the bc-plane.
The Synthesis and the Crystal and Molecular Structure of Tris(N-ethyl-2-pyrrolidone)tetrakis(thiocyanato)cobalt(II)mercury(II), [CoHg(SCN)4(C6H11NO)3]
Authors: Kinoshita Hisashi , Ouchi Akira
Published: July 2006

The title complex, which has a new-type layer structure, has been obtained, and its crystal and molecular structure has been determined by the X-ray diffraction technique. The crystallographic data are: monoclinic, space group P21⁄n, a=18.264(7), b=16.223(7), c=10.623(5) Å, β=92.77(5)° and Z=4. The final R value was 0.059. The cobalt atoms are in an octahedral geometry, ligated by three thiocyanato(SCN) nitrogen atoms and three oxygen atoms (N-methyl-2-pyrrolidone) in a meridional configuration; these cobalt atoms are cross-linked to adjacent mercury atoms by SCN ions, forming a characteristic layer structure which consists of twenty-four-membered rings of the [Co3Hg3(SCN)6] unit. The mercury atoms are in the tetrahedral geometry, ligated by four sulfur atoms of SCN ions, three bridging and one unidentate. The complex layers in parallel are piled up in the a-axis direction, and there are no bridgings or hydrogen bondings between them.
Dinuclear Cobalt(II), Iron(II), and Manganese(II), and Trinuclear Manganese(II) Complexes with Tridentate Ligands of NNS-Donor Set Derived from 2-Aminoethanethiol
Authors: Handa Makoto , Okawa Hisashi , Kida Sigeo
Published: July 2006

Thiolate-bridged dinuclear cobalt(II), iron(II), and Manganese(II) complexes and trinuclear manganese(II) complexes of thiolic ligands, 2-[(2-aminoethyl)amino]ethanethiol, 2-[(3-aminopropyl)amino]ethanethiol, 2-[(2-pyridylmethyl)amino]ethanethiol, and 2-[[(2-pyridylethyl]amino]ethanethiol, were prepared and their magnetic properties were examined in the temperature range 80–300 K. The results indicated a significant antiferromagnetic spin-exchange interactions through the bridging sulfur atom for all the complexes.
A Short Step Synthesis of 3-Deoxy-d-manno-2-octulosonic Acid (KDO)
Authors: Itoh Hiroshi , Kaneko Tuyoshi , Tanami Kazuhiro , Yoda Kazue
Published: July 2006

3-Deoxy-d-manno-2-octulosonic acid (KDO) 1,4-lactone was synthesized from aldehydo-d-mannose derivatives by Horner–Emmons reaction in two steps.
Oxidative Formation of a Blue Pigment from a Dihydropyrrolo[2,1-a]isoquinolin-3(2H)-one Derivative
Authors: Irikawa Hajime , Ooe Sumio , Okumura Yasuaki
Published: July 2006

A dimeric blue pigment was formed by the autoxidation of a dihydropyrrolo[2,1-a]isoquinolin-3(2H)-one derivative.
Asymmetric Addition of Organometallic Reagents to Homochiral β-Ketoacetals
Authors: Hosokawa Takahiro , Yagi Tetsushi , Ataka Yoshiharu , Murahashi Shun-Ichi
Published: July 2006

The diastereoselectivity of the carbonyl addition of organolithium reagents to β-keto acetals was examined. Addition of MeLi to β-keto acetal derived from Pd(II)-catalyzed acetalization of phenyl vinyl ketone with (R,R)-2,4-pentanediol gave (4R,6R)-4,6-dimethyl-2-[(2R)-2-hydroxy-2-phenylpropyl]-1,3-dioxane in 75%de.
The Long-Term Testing of ZSM-5-Type Zeolite Containing Strontium for the High-Temperature Conversion of Methanol to Olefin
Authors: Okado Hideo , Sano Tsuneji , Suzuki Kunio , Okabe Kiyomi , Takaya Haruo
Published: July 2006

Using ZSM-5-type zeolites containing alkaline earth metals (Mg, Ca, Sr), long-term tests for methanol conversion were carried out for up to 1000 h at 550 °C under a methanol LHSV of 2.3 h−1. Strontium-containing zeolite showed the most stable activity. This was attributed to the effect of strontium on the acidity of the zeolite.
Kinetic Studies by Means of the NMR Techniques. I. Acid-Catalyzed Proton-Exchange Reactions of Some Substituted Phenols
Authors: Yoshino Akihiro , Nakashima Yasuki , Takahashi Kensuke
Published: July 2006

A kinetic study was conducted on the acid-catalyzed proton–deuteron-exchange reactions of several substituted phenols. The rates of the exchange were determined by using the two-bond isotope shifts (2Δ) on the carbons and the pattern-fitting analyses for the 13C NMR signals. The observed reaction rates can be expressed additively with substituent parameters. The parameters of the para positions are linearly correlated to the σp+ with ρ=−3.6.
ESR Studies on Mn(II) Ions in Japanese Marine Pearls
Authors: Li Yong , Tajima Kunihiko , Ishizu Kazuhiko , Azuma Nagao , Miyoshi Kiyonori
Published: July 2006

X-band and Q-band ESR measurements of Mn(II) ions contained in Japanese cultured marine pearls and pearl oyster (Pinctada fucata) were carried out at room temperature. The ESR spectra observed for the powdered samples of nacreous and prismatic layers revealed the ESR hyperfine structures typical to Mn(II) in an aragonite lattice and a calcite lattice, respectively. The ESR spectra were interpreted with the following spin Hamiltonian.

\mathscrH=gβH·S+aS·I–gnβnH·I+D[Sz2–S(S+1)⁄3]+E(Sx2–Sy2)

The resonance fields for all the M=+1⁄2↔M=−1⁄2 ESR transitions were derived, with the third-order corrections all taken into account. The zero-field splitting parameters D and E for Mn(II) ions in these biominerals were estimated by computer simulations of the ESR line shapes. The estimated parameters for the nacreous Mn(II) ion (D=20.8 mT, E=6.9 mT) are apparently different from those for the prismatic Mn(II) ion (D=8.5 mT, E=1.4 mT).
Evaluation of Kinetic Parameters from Steady-State Voltammograms at Ultramicrodisk Electrodes
Authors: Abe Takayuki , Itaya Kingo , Uchida Isamu , Aoki Koichi , Tokuda Koichi
Published: July 2006

Platinum ultramicrodisk electrodes 0.8 μm in radius were constructed by anodic electropolishing of a platinum wire followed by sealing it with soft glass. Voltammograms for oxidation of [Mo(CN)8]4−, Fe2−, and [Fe(CN)6]4−, being of a sigmoidal form, were measured at these electrodes and microdisk electrodes with 7.5 μm in radius under the essentially steady-state condition. A voltammogram of Fe2+ at 7.5 μm electrode was drawn out, exhibiting a halfwave potential shifted from the formal potential. This trend was more distinctive for a wave at 0.8 μm electrode. Radii of the electrodes and diffusion coefficients of the electroactive species were determined consistently from the limiting currents. The conventional log-plot showed that electrode reactions of Fe2+ and [Fe(CN)6]4− were, respectively, totally irreversible and almost reversible at these electrodes. Application of the modified log-plot to the voltammograms yielded straight line, of which slope allowed us to evaluate the transfer coefficient and of which intercept gave values of the charge-transfer rate constant. Simulated voltammograms at these values were in good agreement with experimental ones.
Structure Images of a Nickel Fine-Particle Catalyst and Analysis of a Moiré Pattern
Authors: Noda Michio , Ichinose Hideki , Saito Yasukazu , Ishida Yoichi
Published: July 2006

Conventional HR-TEM was applied to a nickel fine-particle catalyst that had been prepared by means of a gas-evaporation method. A structure image of the nickel fine particle showed that the particle consisted of an fcc nickel crystal and thin oxide layers of the surfaces. A platinum-deposited nickel fine particle exhibited a moiré pattern, which was analyzed by the use of the Cowley-Moodie dynamical theory of diffraction. An accurate solution of the equations showed that a platinum lattice obliquely piled on a surface lattice of the particle.