Bulletin of the Chemical Society of Japan
Online ISSN : 1348-0634
Print ISSN : 0009-2673
ISSN-L : 0009-2673
Volume 79 , Issue 1
Showing 1-24 articles out of 24 articles from the selected issue
Award Accounts
The Chemical Society of Japan Award for Creative Work for 2003
  • Hideo Hosono, Toshio Kamiya, Masahiro Hirano
    2006 Volume 79 Issue 1 Pages 1-24
    Published: 2006
    Released: January 13, 2006
    JOURNALS FREE ACCESS
    This review article describes recent progress in our research on cultivation of functionality in crystalline and amorphous transparent oxides utilizing nanostructures embedded in the material itself. It includes the background of our research and approach. Subjects included are material exploration and device application of transparent oxide semiconductors for transparent electronics, function emergence in nano-porous crystal 12CaO·7Al2O3 utilizing active anion species stabilized by sub-nanometer-sized cages, and modified silica glass for vacuum/deep ultraviolet lasers. Our description of each subject include: background and approach, material design concept, fabrication or modification method, properties, and device fabrication. Emphasis is placed on the importance of a variety of built-in nanostructures in transparent oxides for novel function realization and the high potential of transparent oxides as ingredients for an ubiquitous element strategy of material research in this century.
Accounts
  • Kunio Awaga, Toshiyuki Tanaka, Takahiro Shirai, Masato Fujimori, Yosuk ...
    2006 Volume 79 Issue 1 Pages 25-34
    Published: 2006
    Released: January 13, 2006
    JOURNALS FREE ACCESS
    The crystal structures and magnetic properties of heterocyclic thiazyl radicals and related materials have been examined. TTTA (=1,3,5-trithia-2,4,6-triazapentalenyl) exhibited a first-order phase transition between a paramagnetic high-temperature (HT) phase and a diamagnetic low-temperature (LT) phase, with a wide thermal hysteresis loop over the temperature range 230–305 K. The phase control of TTTA was achieved by pressure and by light irradiation. BDTA (=1,3,2-benzodithiazolyl) also exhibited a diamagnetic–paramagnetic phase transition above room temperature. However, fresh samples always exhibited a superheating of the LT phase that resulted in a double melting (melt–recrystallization–melt process) and supercooling of the HT phase, which in turn led to an antiferromagnetic ordering at 11 K. The molecular compounds of thiazyl radicals were prepared; TTTA formed a coordination polymer structure in the TTTA·[Cu(hfac)2 (=bis(hexafluoroacetylacetonato)–copper(II))] crystal, where a ferromagnetic coupling was found between the organic and inorganic species. The cation radical salts, [BBDTA (=benzo[1,2-d:4,5-d′]bis[1,3,2]dithiazole)]·MCl4 (M = Ga and Fe), exhibited ferromagnetic ordering at 7 K and ferrimagnetic ordering at 44 K after evaporation of crystal solvents. We also grew crystals of M–TTDPz (TTDPz = tetrakis(thiadiazole)porphyrazine and M = H2, Fe, Co, Ni, Cu, and Zn) and performed their structural analyses. Their crystal structures were found to depend strongly on the central metal ion and could be classified into three forms: α, β, and γ.
  • Akio Ojida, Itaru Hamachi
    2006 Volume 79 Issue 1 Pages 35-46
    Published: 2006
    Released: January 13, 2006
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    Protein phosphorylation represents a ubiquitous mechanism for controlling diverse protein functions and plays central role in signal transduction cascades in living cells. In order to elucidate the complex network of phosphorylation-based signaling, it is desirable to develop versatile methods and molecular probes that can selectively recognize and detect the phosphoprotein of interest. We present herein the molecular recognition and fluorescence sensing of phosphorylated proteins/peptides by synthetic small molecules. The chemosensors are designed to utilize metal–ligand interaction as a main binding force and thus possess two Zn(II)–dipicolylamine(dpa)s as the binding sites for phosphate group(s) on the protein/peptide surface. We propose the two strategies for recognition of phosphorylated protein/peptide surface; (i) cooperative-binding strategy and (ii) cross-linking strategy. The binuclear anthracene-type chemosensors are designed to interact with a phosphate group on protein/peptide surface based on the cooperative-binding mode, in which the single phosphate group is recognized by the two Zn(II)–dpa sites of the chemosensor. The binding affinity of the chemosensors sensitively depends on the sequence of the phosphopeptide, and reaches to nearly 107 M−1 for a highly negatively charged peptide. In addition, the chemosensors increase their fluorescence upon binding to the phosphorylated proteins/peptides. Therefore, they can distinguish between phosphorylated and non-phosphorylated state of proteins/peptides by their fluorescence intensities. Detailed experiments clarify that the phosphate anion-assisted binding of the second Zn(II) to the binuclear chemosensors is crucial for the fluorescence increase upon binding to the phosphorylated derivatives. The other approach to recognize phosphorylated protein surface by synthetic small molecule is based on the cross-linking strategy. The chemosensors possess bipyridine as a spacer unit between two Zn(II)–dpa sites, which are arranged at appropriately distal position, thereby make possible the cross-linking interaction with two phosphate groups on protein surface. The chemosensors shows higher affinity for the bis-phosphorylated peptide than for the mono-phosphorylated one, indicating that the cross-linking interaction is effective for recognition of multisite phosphorylation domains of a protein. The results presented in this article are regarded as the first step toward detection of specific phosphorylation event of a protein in complicated biological systems using synthetic small molecules. The bioanalytical application of these chemosensors, such as the fluorescence detection of phosphatase catalyzed dephosphorylation and the selective staining of phosphoprotein in SDS-PAGE, are also discussed.
BCSJ Award Article
  • Yoshinori Iiguni, Hitoshi Watarai
    2006 Volume 79 Issue 1 Pages 47-52
    Published: 2006
    Released: January 13, 2006
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    An electromagnetophoretic force has been applied for the measurement of the adsorption force of a single polystyrene particle to a silica surface in electrolyte solutions. By the electromagnetophoretic buoyancy, polystyrene microparticles in a fused-silica capillary were made to migrate perpendicular to the wall of the capillary. A switching of the current direction and a gradual increase of the current under a homogeneous magnetic field of 10 T could desorb the single particle from the wall and allowed us to measure the adsorption force from the desorbing current with a sensitivity of pN. By this method, the adsorption forces of polystyrene particles on a bare surface and on a squalane-coated fused-silica surface were measured in the absence and the presence of surfactants such as Triton X-100, cetyltrimethylammonium bromide, and sodium dodecyl sulfate. The observed adsorption forces showed that the roles of the surfactants included not only the reduction of the adsorption force as a spacer, but also the production of a characteristic force due mainly to electrostatic interaction.
Articles
  • Kazunari Yoshizawa, Naoki Kihara, Yoshihito Shiota, Hidetake Seino, Ya ...
    2006 Volume 79 Issue 1 Pages 53-58
    Published: 2006
    Released: January 13, 2006
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    The electronic properties of cubane-type mixed-metal sulfido clusters with an Mo(V)2Ru(II)2S4 core and possible dinitrogen activation on it are described from DFT computations. The cluster [(CpRu)2{MoCl2(MeCN)}23-S)4] (Cp = η5-C5H5), whose Cp* analogue (Cp* = η5-C5Me5) was isolated and fully characterized by X-ray crystallographic analysis, has a closed-shell singlet ground state. Upon release of the acetonitrile ligands, the ground state remains in a closed-shell singlet state, the corresponding open-shell singlet and triplet states lying 2 kcal mol−1 above the closed-shell singlet state. Dinitrogen can hardly coordinate to this neutral [(CpRu)2(MoCl2)23-S)4] cluster. However, upon reduction by two electrons the binding energy for two N2 molecules to the resultant anionic cluster [(CpRu)2{MoCl2(N2)}23-S)4]2− increases to 4 kcal mol−1. This interaction, which still seems too weak to become isolable, is analyzed in terms of molecular orbitals to increase our understanding of dinitrogen activation by synthetic systems. The HOMO of [(CpRu)2(MoCl2)23-S)4]2− is pointing toward missing ligands and can interact effectively with the πg* orbitals of dinitrogen. This orbital might play a role in the binding of dinitrogen.
  • Sumita Roy, Joykrishna Dey
    2006 Volume 79 Issue 1 Pages 59-66
    Published: 2006
    Released: January 13, 2006
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    A new class of N-acylamino acid surfactants, sodium N-(11-acrylamidoundecanoyl)-L-valinate (SAUV) and -L-threoninate (SAUT), were synthesized and characterized in aqueous solutions. The self-assembly properties were studied by surface tension, fluorescence probe, light scattering, and microscopic techniques. The interfacial properties of the amphiphiles have been investigated at the air/water interface. The critical aggregation concentration (cac) and free energy change of aggregation for both amphiphiles were determined. The results of fluorescence probe and surface tension studies have indicated that initially flat bilayer structures are formed, which upon a further increase of surfactant concentration transform into closed vesicles. The pH and temperature dependence of the bilayer aggregates have been studied. The role of intermolecular hydrogen bonding between amide groups upon aggregation towards microstructure formation in solution has been elucidated. The micropolarity of the hydrophobic domains of the bilayer self-assemblies was estimated by fluorescence probe methods. Dynamic light scattering measurements were performed to determine the mean size of the aggregates. The circular dichroism spectra of SAUV and SAUT suggested the formation of chiral aggregates in dilute solution. The transmission electron micrographs revealed the presence of closed vesicles and twisted ribbons in the aqueous solutions of the amphiphiles. Optical microscopic images also showed the existence of twisted ribbons and rope-like helical structures in the case of SAUV.
  • Mohammad Mehdi Papari, Delara Mohammad-Aghaie, Jalil Moghadasi, Ali Bo ...
    2006 Volume 79 Issue 1 Pages 67-74
    Published: 2006
    Released: January 13, 2006
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    The purpose of this paper is to extract information about intermolecular pair interaction potential energy and then predict the dilute gas transport properties of Ar–F2 and F2 systems. The potential energies of the two aforementioned systems have been compared with the LJ (12-6) and m-6-8 model potentials. A rather accurate correlation for the viscosity coefficients of each system, which encompasses a temperature range 200 K < T < 3273.15 K, was reproduced from the calculated intermolecular potential energies. The predicted viscosities of Ar–F2 and F2 systems deviate from the literature data to within 1 and 2%, respectively. Furthermore, the calculated potential energies were used to present smooth correlations for other transport properties.
  • Dae Youl Baek, JinHai Chen, Jinguo Wang, Atsushi Doi, Shunji Kasahara, ...
    2006 Volume 79 Issue 1 Pages 75-79
    Published: 2006
    Released: January 13, 2006
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    Doppler-free two-photon excitation spectra and the Zeeman effects for the 1021401 and 1011401 bands, whose vibrational excess energies are 3412 and 2492 cm−1, respectively, of the S1 1B2u ← S0 1A1g transition in gaseous benzene-h6 have been measured. Rotationally resolved lines up to a rotational excess energy of 945 cm−1 in the 1011401 band, whose excess energy is isoenergetic with the one of the 1021401 band at low J, have been observed. The density of perturbation is observed to increase around the K = 0 and K = J levels in the 1011401 band as the rotational energy increases, but line broadening is not observed. It was reported that only the K = 0 lines at low J and the K = J lines at high J were observed as a sharp line and the rest was washed out by broadening in the 1021401 band. The assignments are confirmed by the Zeeman spectra. The character and magnitude of Zeeman splittings in both bands could be understood as originating from the electronic orbital angular momentum arising from a mixing of the S1 1B2u and S2 1B1u states via JL coupling. The levels of the S1 1B2u state are found not to be mixed with a triplet state by the Zeeman effect.
  • Maw-Ling Wang, Ze-Fa Lee
    2006 Volume 79 Issue 1 Pages 80-87
    Published: 2006
    Released: January 13, 2006
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    In the synthesis of bisphenol A diallyl ether from bisphenol A and allyl bromide, the liquid–liquid mode of operation catalyzed by quaternary ammonium salts was carried out in an alkaline solution/organic solvent two-phase medium. The mono-substituted product was not detected during or after the reaction. In this work, a rational reaction mechanism is proposed and a kinetic model then established. The apparent rate constant of the organic-phase reaction was obtained from experimental data. The effects of the reaction conditions, including agitation speed, organic solvents, quaternary ammonium salts, inorganic salts, temperature, alkali compounds, amount of potassium hydroxide, and water on the conversion of allyl bromide, were investigated in detail. The presence of a small amount of tetrabutylammonium bromide (TBAB) in the chlorobenzene/water system produced a rate over several folds larger than that of the reaction system in the absence of phase-transfer catalyst. The presence of alkali compounds promoted the formation of alkoxide and enhanced the extractive efficiency due to the salting out effect. The present etherification via phase-transfer catalyst could operate at lower temperatures to avoid Claisen rearrangement, which usually occurs at higher temperatures. Rational reasons to account for the absence of mono-substituted product are explained satisfactorily. Peculiar phenomena in investigating the effects of the volume of organic solvent, amount of KOH, and the volume of water and alkali compounds on the apparent rate constants are also explained.
  • Anees Ahmad, Mohd. Rafatullah, Md. Danish
    2006 Volume 79 Issue 1 Pages 88-94
    Published: 2006
    Released: January 13, 2006
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    Exchange isotherms for hydrogen ion/alkali metal ions (H+/Li+, H+/Na+, H+/K+, H+/Rb+, and H+/Cs+) have been studied at 20, 40, and 60 °C at a constant ionic strength of 0.1 on the crystalline phase of niobium(V) phosphate. The isotherms show an irregular (S-shaped) behavior without a phase transition. A selectivity reversal has been observed over the entire system of solid compositions. Plots of the selectivity coefficient (loge scale) versus equivalent ionic fraction of metal ion in the exchanger phase are linear for all of the systems and at all temperatures studied. The ion-exchange capacities and the maximum uptake at equilibrium is on the order of Li+ < Cs+ < Rb+ < Na+ < K+. The higher selectivity of potassium ion compared to other alkali ions has been explained in terms of steric hindrance and the stiff three-dimensional structure of the exchanger having a fixed pore size. The thermodynamic parameters for the overall and for zero loading have been worked out using the Gaines–Thomas equation.
  • Tohru Saitoh, Koji Mizutani, Masataka Hiraide
    2006 Volume 79 Issue 1 Pages 95-99
    Published: 2006
    Released: January 13, 2006
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    A simple and efficient gas decontamination system has been developed. The method is based on the aeration of an aqueous solution of a thermo-responsive polymer and polymer-mediated extraction followed by flotation. Polyaromatic hydrocarbons (PAHs) in gas phase were dissolved by aeration through the aqueous solution of a water-soluble polymer, poly(N-isopropylacrylamide) [PNIPAAm], containing 0.1 mol dm−3 sodium nitrate and 1% (v/v) ethanol. The efficiency of the dissolution increased with increasing PNIPAAm concentration. PAHs consisting of more than 3 aromatic rings were quantitatively collected in the polymer solution, while the collection of volatile naphthalene was insufficient. Subsequently, on heating the polymer solution to 50 °C, the polymer media incorporating PAHs formed precipitates. The precipitates were floated to the surface of water by bubbling. Hydrophobic PAHs, such as pyrene and benzo[a]pyrene, were highly concentrated into the polymer phase having a very small volume.
  • Sadayuki Himeno, Tadashi Katsuta, Masayo Takamoto, Masato Hashimoto
    2006 Volume 79 Issue 1 Pages 100-105
    Published: 2006
    Released: January 13, 2006
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    A novel diphosphoheptadecatungstate complex, [(P2O7)W17O51]4− was prepared from a 200 mM (M = mol dm−3) W(VI)–10 mM P2O74−–0.6 M HCl–40% (v/v) CH3CN system, and characterized by IR, UV–vis, 31P NMR, and 183W NMR spectroscopy, and voltammetry. Single-crystal X-ray analysis was made on [(C2H5)4N]4[(P2O7)W17O51]·CH3CN, which crystallized in the monoclinic space group P21/n, with cell parameters a = 16.1877(8), b = 22.103(1), c = 22.670(1) Å, β = 90.847(1)°, V = 8110.3(7) Å3, and Z = 4. The anion consists of a PW8O31 fragment derived from a β-Keggin-type [PW12O40]3− structure, and two PW8O31 units are linked by five oxygen atoms and a WO5 square pyramid. The [(P2O7)W17O51]4− anion exhibited a four-step reversible one-electron redox wave in CH3CN, and a three-step two-electron redox wave resulted in the presence of acid. This is the first example of an electrochemically-active diphosphotungstate complex.
  • Rei Okamura, Tetsuaki Fujihara, Tohru Wada, Koji Tanaka
    2006 Volume 79 Issue 1 Pages 106-112
    Published: 2006
    Released: January 13, 2006
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    A platinum(II) complex bearing 1,10-phenanthroline-5,6-dione (phenO2), [PtCl(phenO2-N,N′)(PPh3)]+ ([2]+) was newly prepared and characterized. An X-ray crystallographic study of [2](PF6) revealed that the phenO2 ligand coordinates to platinum with the N,N′-chelate form. The basicity of the quinoid part of phenO2 in [2]+ and of the diimine one in [Pt(phenO2-O,O′)(PPh3)2] with an O,O′-chelate ring (3) was evaluated in the absence and the presence of Li+ by means of UV–vis spectroscopy and cyclic voltammetry. The quinoid group in [2]+ practically had no ability to bind Li+, but induced on anodic potential shift of the phenO2 localized redox potential by 850 mV due to the strong interaction between the reduced form of [2]+ and Li+. Undeniably, a weak interaction of Li+ with the diimine moiety of free phenO2 (K = 3.6 M−1) is greatly enhanced in the interaction between Li+ and the diimine site in 3 because of the electron donation from the catecholato group of the complex.
  • Balasubramaniam Arul Prakasam, Kuppukkannu Ramalingam, Gabriele Bocell ...
    2006 Volume 79 Issue 1 Pages 113-117
    Published: 2006
    Released: January 13, 2006
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    Four new dithiocarbamatonickel(II) complexes [Ni(dchdtc)(NCS)(PPh3)] (1), [Ni(dchdtc)(CN)(PPh3)] (2), [Ni(dchdtc)(PPh3)2]ClO4 (3), and [Ni(dchdtc)(dppe)]ClO4 (4) (dchdtc = N,N-dicyclohexyldithiocarbamate anion, PPh3 = triphenylphosphine, and dppe = 1,2-bis(diphenylphosphino)ethane) were prepared from the parent [Ni(dchdtc)2]. All four complexes were analyzed by CV, UV–vis, IR, and NMR (1H, 13C, and 31P) spectra. 13C NMR spectra of the complexes (14) show the most notable >N13CS2 signals at around 200 ppm. In the cyclohexyl ring, the α-CH carbon is deshielded to a greater extent on complexation. Extraordinary deshielding was observed for the 31P signal in all of the cases, indicating the effective bonding of phosphorus to the metal center. Single crystal X-ray structural analysis of the mixed ligand complexes (13) indicates a decrease in S–Ni–S bite angle when compared to that of the parent bis(dithiocarbamate), due to an increase in steric crowding around the central metal by the introduction of a bulky PPh3. The trans effects on Ni–S bonds can be arranged in the following order: NCS < PPh3 < CN. The S2CN< bond is very short for complex 3, (1.306(3) Å), because of the steric effect exerted by two PPh3 groups and dchdtc. The observed negative reduction potentials follow the order: 1 > 2 > 3, indicating the presence of a higher relative electron density on 1 compared to 2 and 3.
  • Chizu Shimokawa, Yoshimitsu Tachi, Nagatoshi Nishiwaki, Masahiro Ariga ...
    2006 Volume 79 Issue 1 Pages 118-125
    Published: 2006
    Released: January 13, 2006
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    Copper(I) complexes generated by using a series of β-diketiminate ligands (R1,R2LR3−, [(R3)N–C(R2)–C(R1)–C(R2)–N(R3)], see Chart 1; “β-diketiminate” denotes enaminone imine analogs) have been structurally characterized by X-ray crystallographic analysis. In the α-nitro-ligand system (R1 = NO2 and R2 = H), the structure of the resulting products were largely affected by the nitrogen substituent R3, providing bis(β-diketiminato)copper(II) complex 1 [a product of the disproportionation reaction of copper(I)] (R3 = Ph), head-to-tail linear coordination polymer copper(I) complex 2 (R3 = Mes, (mesityl)), and mononuclear copper(I) complex 3 (R3 = Dipp (2,6-diisopropylphenyl)). On the other hand, α-cyano-ligand (R1 = CN and R2 = H or Me) always gave head-to-tail coordination polymer copper(I) complexes (48) regardless of the aromatic substituent R3. In both systems, β-diketiminate ligands exhibited a U-shaped closed conformation, forming a six-membered chelate ring with copper(I). Copper(I) complexes with a β-diketiminate ligand with a W-shaped open conformation were also obtained in the case of α-methyl and α-hydrogen derivatives (R1 = Me or H, R2 = H, and R3 = Dipp). In these cases, the dinuclear and tetranuclear copper(I) macrocyclic complexes 9 and 10 were obtained.
  • Yasuko In, Hirofumi Ohishi, Hiroo Miyagawa, Kunihiro Kitamura, Yasuhir ...
    2006 Volume 79 Issue 1 Pages 126-133
    Published: 2006
    Released: January 13, 2006
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    The absolute configuration of chainin (1), a polyene macrolide antibiotic, was determined by X-ray crystal analyses, and the conformational stability of planar 28-membered ring was confirmed by an ab initio quantum chemical calculation. The most prominent feature observed in the crystal structure was the concerted =C–H···O interactions formed between four conjugated olefinic CH groups and five hydroxyl oxygen atoms of neighboring molecules. The character of the interaction was investigated by IR measurements and quantum chemical calculations, leading to the conclusion that these concerted interactions are powerful enough to form defined intermolecular association of polyene macrolide. Characteristically, this intermolecular association mode allows the proposal of a barrel-stave assembly, comprising eight parallel or antiparallel pairs of 1 via =C–H···O interactions, which serves as a possible ion-permeable membrane channel structure of polyene macrolide, which may be responsible for the antifungal activity in cell membranes.
  • Takahisa Ogamino, Rika Obata, Hiroshi Tomoda, Shigeru Nishiyama
    2006 Volume 79 Issue 1 Pages 134-139
    Published: 2006
    Released: January 13, 2006
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    The reported structure of the natural calafianin (1) and its isomer in the epoxide region 13 were successfully synthesized through the cis- and trans-spiroisoxazoline compounds, which were produced by electrochemical oxidation of the hydroxyimino-phenol derivative 7, followed by Zn[BH4]2 reduction. Comparison of the spectroscopic data of the synthetic (±)-1 and (±)-13 resulted in structural revision of the natural calafianin to 13, possessing the trans-relationship between an epoxide and an oxygen of the isoxazoline. In addition, a significant difference of antimicrobial activity between 1 and 13 is discussed.
  • Ravi Varala, Enugala Ramu, Srinivas R. Adapa
    2006 Volume 79 Issue 1 Pages 140-141
    Published: 2006
    Released: January 13, 2006
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    We report a transition metal-free synthetic protocol for the cross-coupling reaction of aryl bromides and aryl iodides and diphenyl diselenide (Ph2Se2) using CsOH·H2O as a base in DMSO at 110 °C. Using this protocol, we show that a variety of diaryl selenides can be synthesized in moderate to good yields.
  • Md. Delwar Hossain, Tsugio Kitamura
    2006 Volume 79 Issue 1 Pages 142-144
    Published: 2006
    Released: January 13, 2006
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    An easy, safe, and effective method for preparing [bis(trifluoroacetoxy)iodo]arenes, ArI(OCOCF3)2, in high yields from some iodoarenes are reported, using a K2S2O8/CF3COOH/CH2Cl2 system. This procedure avoids the use of high temperature and severe reaction conditions.
  • Yusaku Takita, Yoshitaka Sadatomi, Hiroyasu Nishiguchi, Katsutoshi Nag ...
    2006 Volume 79 Issue 1 Pages 145-148
    Published: 2006
    Released: January 13, 2006
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    The catalytic conversion of chlorobenzene (CB) over some metal phosphates and sulfate was studied in the presence of water vapor and oxygen. The conversion of CB proceeded in the order of AlPO4, Zr3(PO4)4, CePO4–AlPO4, and La2(SO3)3 above 673 K. The major products were CO, CO2, and HCl. The reaction proceeded in the absence of water vapor; however, the activity was greatly reduced in the absence of oxygen. Even in the presence of oxygen, 30 mol % of water vapor inhibited the reaction. No intermediate hydration products were observed. There was no correlation between each of the catalytic activity, the acidity, and the concentration of the surface hydroxys of the catalysts. These results suggest that the essential reaction for CB conversion is oxidation. The specific surface area (SSA) of the catalysts was not changed during the CB conversion.
  • Hiroyasu Okuo, Toru Asahi, Takahiro Onoue, Tetsuya Osaka
    2006 Volume 79 Issue 1 Pages 149-153
    Published: 2006
    Released: January 13, 2006
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    The relationship between human sensation experienced in the use of a material and its physical properties was investigated for the case of writing with a ball-point pen containing water-based ink. Friction force microscopy (FFM) and a writing tester were used to measure friction in nano- and macro-scale, respectively, and their results were correlated with the smoothness of the act of writing. FFM allowed the determination of the optimum concentration of a specific lubricant to be incorporated in the ink to minimize the wear of the bearing material, although no significant relationship was observed with the writing tester. The nano-tribological measurements by FFM provide a significant means to understand the relationship between materials and the smoothness of the act of writing.
  • Shinichi Komaba, Fuminobu Mikami, Tatsuya Itabashi, Mamoru Baba, Taku ...
    2006 Volume 79 Issue 1 Pages 154-162
    Published: 2006
    Released: January 13, 2006
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    To improve the electrochemical properties of the silicon film anode in lithium cells, we prepared three types of silicon based-films, i.e., intrinsic silicon, n-type silicon, and Ag10Si90 binary films using r.f. magnetron sputtering. Based on galvanostatic charge–discharge tests and a.c. impedance measurements, the n-type silicon film and Ag10Si90 binary film cells exhibited a superior cycle life and lower electrochemical resistance compared with the intrinsic silicon film cell. The potential variation in the electrochemical alloying/de-alloying reactions of the Ag10Si90 binary film with lithium was different from that of the intrinsic silicon film, meaning that the Ag ingredient in the binary film affected the charge–discharge reaction. Furthermore, when a Ni plate roughened by chemical etching was used as a substrate, the Ag10Si90 film anode demonstrated an excellent capacity retention during 400 cycles with a high discharge capacity of >200 μA h cm−2 (corresponding to 1500 mA h g−1) at 0.5 mA cm−2 (2.5 C).
  • Yuki Morita, Fusheng Zhang, Takeyasu Tasaka, Remuto Yamaguchi, Hiroaki ...
    2006 Volume 79 Issue 1 Pages 163-169
    Published: 2006
    Released: January 13, 2006
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    The liquid crystal properties of 3H-2-oxobenzofuran-6-yl 4-(n-CnH2n+1O)benzoates (1-n, n = 5–12), 4′-(n-CnH2n+1O)biphenyl-4-carboxylates (2-n, n = 6–10), and 4-(n-CnH2n+1)benzoates (3-n, n = 4–6) are described. The n = 5–8 homologues of 1-n exhibit a nematic (N) phase, and the n = 8–12 homologues exhibit a smectic A (SmA) phase, where the layer spacing is ca. 1.3 times of the calculated molecular length. The homologues of 2-n show a complex phase-transition behavior involving a smectic C (SmC), two kinds of SmA, reentrant nematic, and N phases, where the SmC phase is exhibited by the n = 6–8 homologues. The layer spacings of SmA phases formed at high and low temperature regions correspond to 1.3 and 1.0 times of the molecular lengths, respectively. The polar interactions around the terminal lactone moiety are assumed to play important roles for the complex polymesomorphism and diversity of the smectic layer structure.
  • Masaki Matsui, Saori Tanaka, Kazumasa Funabiki, Toru Kitaguchi
    2006 Volume 79 Issue 1 Pages 170-176
    Published: 2006
    Released: January 13, 2006
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    The UV–vis absorption and fluorescence spectra, solubility, and application as emitters in single-layer organic electroluminescence (EL) devices of novel quinacridone- and squarylium-dye-centred dendrimers (Gn-QAs and Gn-SQs) were examined. The respective dendrimers showed no remarkable differences in the UV–vis absorption (λmax) and photoluminescence (PL) maxima (λem). The solubility of dendrimers drastically increased at higher generation. The EL maxima of Gn-QAs and Gn-SQs were observed at 522 and 710 nm, respectively. In the case of Gn-QAs, the EL intensity under the fixed bias voltage decreased at higher generation due to a decrease in energy transfer from the host molecules to QA. Meanwhile, in the case of Gn-SQs, the EL intensity increased upon higher generation because of increased current density and the improvement of concentration quenching.
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