Bulletin of the Chemical Society of Japan
Online ISSN : 1348-0634
Print ISSN : 0009-2673
ISSN-L : 0009-2673
Volume 80 , Issue 10
Showing 1-25 articles out of 25 articles from the selected issue
Vol. 80 Commemorative Accounts
  • Héctor D. Abruña, Futoshi Matsumoto, Jamie L. Cohen, Jin ...
    2007 Volume 80 Issue 10 Pages 1843-1855
    Published: October 15, 2007
    Released: October 12, 2007
    JOURNALS FREE ACCESS
    We illustrate our current work for electrochemical energy generation and storage (i.e., fuel cells and lithium-ion batteries, respectively). In fuel cell research, we have been developing Pt-based ordered intermetallic compounds as electrocatalysts towards anodic reactions of liquid fuels such as methanol, ethanol, and formic acid for proton-exchange membrane fuel cells (PEMFCs). Development of the intermetallic compounds ranges from bulk materials to nanoparticles. In our work, we have employed a combinatorial method to achieve rapid screening of a large number of potential electrocatalysts. Multi-element sputtering was employed to generate films with different compositions including most of a phase diagram and the resulting libraries were screened using a fluorescence assay. For portable applications, we have also developed a planar microfluidic membraneless fuel cell (PMMFC) device, which eliminates the need for a polyelectrolyte membrane (PEM) and takes advantage of the laminar flow of fuel and oxidant streams. Particularly, in order to increase power density (cell voltages) of a PMMFC device, we have focused on the development of a dual electrolyte PMMFC in which alkaline and acid electrolyte solutions are employed for fuel and oxidant streams, respectively. In lithium-ion battery research, we have been designing new cost-effective organic materials with high energy densities as cathode electroactive materials, targeting large applications such as electrically powered automotives. In particular, we have focused on organosulfur-based polymers, involving the redox chemistry of thiolates (RS), capable of higher energy density than conventional lithium metal oxides such as LiCoO2. By combining electrochemical techniques with computational methods and organic synthesis, we have tried to establish an efficient procedure to develop novel organic-based electroactive materials suitable for the demands of energy storage materials for rechargeable lithium-ion batteries.
    We illustrate our current work for electrochemical energy generation and storage devices. The development of Pt-based ordered intermetallic compounds as anode electrocatalysts for fuel cells and organosulfur-based compounds as high-energy cathodes for lithium-ion batteries is discussed. Fullsize Image
  • Ivan Aprahamian, Ognjen Š. Miljanic, William R. Dichtel, Kyosuk ...
    2007 Volume 80 Issue 10 Pages 1856-1869
    Published: October 15, 2007
    Released: October 12, 2007
    JOURNALS FREE ACCESS
    The CuI-catalyzed Huisgen 1,3-dipolar cycloaddition, popularized as “click chemistry,” is one of the latest acquisitions to the synthetic arsenal for the making of mechanically interlocked molecular compounds. The high efficiency and functional group tolerance of “click chemistry” allows this reaction to be employed at the stoppering step in the “threading-followed-by-stoppering” sequence that produces rotaxanes, and in the macrocyclization step that affords catenanes. The use of this kind of “click chemistry” alleviates some of the drawbacks associated with previous approaches to the template-directed synthesis of mechanically interlocked molecular compounds—approaches such as “clipping;”—and opens up the way to more exotic mechanically interlocked molecules. Employing this new approach, [2]-, [3]-, and [4]rotaxanes and [2]catenanes have all been prepared in a convergent and efficient manner. Their template-directed synthesis relies, in the beginning, on the formation of [n]pseudorotaxanes, which can either (i) be stoppered, affording [n]rotaxanes, or (ii) induced to undergo an intramolecular cyclization, affording [2]catenanes. This new synthetic approach has also been employed in the template-directed synthesis of a self-complexing system as well as a two-station, degenerate [2]rotaxane (molecular shuttle) which was used to measure the energy barrier (15 kcal mol−1) to shuttling by a cyclobis(paraquat-p-phenylene) ring between two identical 1,5-dioxynaphthalene (DNP) stations across a 1,2,3-triazole unit. It has also been found that the CuI-salt, employed in the click reaction between an azide and an alkyne, can act as both a catalyst and a template in the formation of [2]rotaxanes. The “click” approach has also been used in the formation of a bistable [2]rotaxane containing a DNP station and a tetrathiafulvalene one. Electrochemical experiments performed on this compound indicate that the presence of the triazole unit does not influence the kinetics or thermodynamics of the redox-controlled switching process. Finally, the synthesis of a liquid-crystalline bistable [2]rotaxane, which shows smectic A phase behavior over a wide range of temperatures, is described.
    The CuI-catalyzed Huisgen 1,3-dipolar cycloaddition can be used in the efficient and divergent synthesis of mechanically interlocked molecules, such as [n]rotaxanes and [2]catenanes. The simplicity of the required precursors and the straight-forwardness of the reaction establish this type of “click chemistry” as an indispensable strategy for the synthesis of mechanically interlocked molecular compounds. Fullsize Image
Award Accounts
  • Hiroki Oguri
    2007 Volume 80 Issue 10 Pages 1870-1883
    Published: October 15, 2007
    Released: October 12, 2007
    JOURNALS FREE ACCESS
    Ciguatoxins are the major causative toxins in ciguatera seafood poisoning. The limited availability of ciguatoxins has precluded structural elucidation and development of a reliable and specific immunoassay for detecting the toxins in contaminated fish. To seek a solution for the longstanding problem of ciguatera, we addressed the synthetic challenge by utilizing rationally designed model compounds of ciguatoxins. The C2 configuration and entire absolute configuration of ciguatoxin were successfully elucidated with minutest amounts of natural toxins, using an approach which combined partial structure synthesis, microscale chemical transformations, and the CD exciton chirality method. On the basis of the absolute configuration, the partial structures of ciguatoxins were designed and synthesized as haptens for the preparation of anti-ciguatoxin antibodies. Monoclonal antibodies (mAbs) against both ends of ciguatoxin CTX3C were prepared by immunization of mice with protein conjugates of synthetic haptens of the ABCDE-ring and the IJKLM-ring, in place of the natural toxin. Haptenic groups with surface areas larger than 400 Å2 were required to produce mAbs, which could bind strongly to CTX3C itself. A direct sandwich enzyme-linked immunosorbent assay (ELISA) using these mAbs was shown to detect CTX3C at the ppb level with no cross-reactivity against other related marine toxins, including brevetoxin A, brevetoxin B, okadaic acid, or maitotoxin. In order to make the sandwich immunoassay protocol a general method for detecting other ciguatoxins congeners, the preparation of mAbs for the left-end of ciguatoxin was investigated. Expeditious synthesis of the left end of ciguatoxin with installation of the 3-butene-1,2-diol side-chain of the A-ring as well as surface plasmon resonance (SPR) analysis of the antibody–hapten interactions are also described.
    A synthetic approach using rationally designed molecules based on partial structures of ciguatoxins offered a solution to longstanding problems related to ciguatera seafood poisoning. Fullsize Image
BCSJ Award Article
  • Noriyoshi Nagahora, Takahiro Sasamori, Yasuaki Watanabe, Yukio Furukaw ...
    2007 Volume 80 Issue 10 Pages 1884-1900
    Published: October 15, 2007
    Released: October 12, 2007
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    Kinetically stabilized 1,1′-bis[(E)-diphosphenyl]ferrocenes were synthesized by taking advantage of extremely bulky substituents, 2,4,6-tris[bis(trimethylsilyl)methyl]phenyl (denoted as Tbt) and 2,6-bis[bis(trimethylsilyl)methyl]-4-[tris(trimethylsilyl)methyl]phenyl (denoted as Bbt) groups, and characterized by the spectroscopic and X-ray crystallographic analyses. The electronic structures of the 1,1′-bis[(E)-diphosphenyl]ferrocenes were determined by analyzing electronic spectra, the transitions of which were reasonably assigned based on theoretical calculations. In the cyclic voltammograms, there were two well-defined reversible one-electron reduction couples corresponding to the intramolecular two diphosphene units. Furthermore, the 1,1′-bis[(E)-diphosphenyl]ferrocene was found to undergo ligand-exchange reactions with group 6 metal carbonyl complexes along with the E-to-Z isomerization of the diphosphene moieties, leading to the formation of the corresponding 1,1′-bis[(Z)-diphosphenyl]ferrocene group 6 metal tetracarbonyl complexes, [M(CO)4{(Z,Z)-(BbtP=PC5H4)2Fe}] (M=Cr, Mo, and W). The molecular structures of these complexes were determined by spectroscopic analyses (1H, 13C, and 31P NMR spectra, and UV–vis spectra), and that of the tungsten complex was determined by X-ray crystallographic analysis. Several types of d→πP=P electron transitions due to the iron and group 6 metals were detected by using UV–vis spectroscopy, and these results were supported by theoretical calculations.
    Kinetically stabilized 1,1′-bis[(E)-diphosphenyl]ferrocenes were synthesized by taking advantage of extremely bulky substituents, 2,4,6-tris[bis(trimethylsilyl)methyl]phenyl (Tbt) and 2,6-bis[bis(trimethylsilyl)methyl]-4-[tris(trimethylsilyl)methyl]phenyl (Bbt) groups, and characterized by the spectroscopic and X-ray crystallographic analyses. Fullsize Image
 
  • Seyed Hosein Mousavipour, Vahid Saheb
    2007 Volume 80 Issue 10 Pages 1901-1913
    Published: October 15, 2007
    Released: October 12, 2007
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    The kinetics and mechanism of reaction of a hydroperoxyl radical (HO2) with a hydrogen atom on both singlet and triplet surfaces were studied by employing DFT, CCSD, and G3 methods along with the Aug-cc-pVTZ basis set. MC-SCF and CCD methods were used to explore potential energy surfaces. Major end products from different channels were H2O+O, H2+O2, and OH. Formation of chemically activated hydrogen peroxide HOOH was the most exothermic path in this system that dissociates to the ground state OH(2Π) radicals. Another energized transient species was water oxide H2OO, which has local minimum on the singlet potential-energy surface. The energized water oxide rapidly isomerized to hydrogen peroxide HOOH or dissociated to H2O + O(1D). Transition state theory and RRKM theory were used to calculate the rate constants for different channels.
  • Hossein Roohi, Batol Mackiabadi
    2007 Volume 80 Issue 10 Pages 1914-1919
    Published: October 15, 2007
    Released: October 12, 2007
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    The conformational geometries of the FO3 complexes were investigated computationally in the doublet state. Geometry optimization and frequency calculations were performed at the CCSD/aug-cc-pVDZ, CCSD/6-311+G(d) and QCISD/aug-cc-pVDZ levels of theory. To improve the energies, single point calculations were carried out based on the CCSD/aug-cc-pVDZ, QCISD/aug-cc-pVDZ, and CCSD/6-311+G(d) geometries using the CCSD(T), QCISD(T), and CASSCF methods. One non-planar and two planar conformational geometries of the FO3 complex were found in the doublet state. From energy analysis, the planar geometry with a dihedral angle (φO1O2O3F) of 0.0° was the most stable one. In addition, vibrational frequencies obtained by CCSD and QCISD methods confirm that the planar geometry of the complex is similar to that reported under the experimental conditions. Quantum theory of Atom In Molecule (QTAIM) was also employed to characterize the electronic properties of the conformational geometries of FO3 complex.
  • Akifumi Oda, Megumi Okayasu, Yukiko Kamiyama, Tomoki Yoshida, Ohgi Tak ...
    2007 Volume 80 Issue 10 Pages 1920-1925
    Published: October 15, 2007
    Released: October 12, 2007
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    We evaluated the docking accuracy of ArgusLab, which is a freely available software program for computational docking, using experimentally determined protein–ligand complex structures. Investigations of the roles of parameters used for docking calculations in ArgusLab were carried out in addition to evaluation of the software. The results indicate that one docking engine of ArgusLab, GADock, is superior in terms of accuracy, and that another docking engine, ArgusDock, is advantageous in terms of the computational time it provides. In a pose construction step, larger population sizes generated more accurate poses using GADock. The docking poses constructed by GADock were easier to evaluate than those of ArgusDock in the pose-selection step. Reliable docking calculations are expected to be carried out with ArgusLab using results of this study.
  • Yasuyuki Tsuboi, Masayuki Nishino, Yasutaka Matsuo, Kuniharu Ijiro, No ...
    2007 Volume 80 Issue 10 Pages 1926-1931
    Published: October 15, 2007
    Released: October 12, 2007
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    We demonstrate that phase separation of an aqueous poly(vinyl methyl ether) (PVME) solution can be triggered not only by a temperature change but also by photon pressure. A near-infrared continuous wave laser beam (λ=1064 nm) was focused through an objective lens into a heavy water (D2O) solution of PVME. A single PVME microparticle was produced and trapped at the focal point of the laser beam within several hundreds of seconds after switching on the laser. The origin of the microparticle formation (phase separation) is ascribed essentially to the photon force of the laser beam, and not to a rise in the local temperature, since heavy water is transparent at 1064 nm. The structures of the PVME microparticles produced by laser irradiation were studied in detail using confocal Raman microspectroscopy. Raman spectra of the microparticles and coiled/globular PVME were observed successfully over a wide wavenumber region. It was confirmed that the phase transition of the polymer chains from coiled to globular states proceeded during microparticle formation. The fundamental mechanism of photo-induced phase separation of PVME is discussed in terms of the interactions between the polymer and the photon force.
  • Yoshimi Sueishi, Mieko Negi, Yashige Kotake
    2007 Volume 80 Issue 10 Pages 1932-1938
    Published: October 15, 2007
    Released: October 12, 2007
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    Previously, we demonstrated, for the first time, that guest probes having more than one bulky group could produce a pair of bidirectional inclusion complexes with water soluble calixarene (Chem. Lett. 2006, 35, 772). The use of unique free radical probes and electron spin resonance has made this finding possible. In this report, we investigated thermodynamic and pH-dependent properties of the group-inclusion complex formation, i.e., the effects of temperature, pressure and the medium pH on group inclusion by p-sulfonatocalixarenes were determined. Temperature-dependence study indicated that enthalpy portions in ΔG play dominant roles in the group-in complexation. Pressure dependence experiments allowed us to calculate the reaction volumes, i.e., intrinsic volume changes related to inclusion into the calixarene cavity, which ranged from −5.1 to −16.3 cm3 mol−1. Data on pH dependence clarified the role of oxyanions in the entrant group of calixarenes. It should be emphasized that pressure-dependent study provided unique information on the structure of the group-inclusion complex.
  • Katsuhiro Tamura, Toshio Watanabe, Takayoshi Ishimoto, Umpei Nagashima
    2007 Volume 80 Issue 10 Pages 1939-1941
    Published: October 15, 2007
    Released: October 12, 2007
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    Difference in the potential energy surfaces (ΔE) obtained from the fragment MO (FMO) method and conventional ab initio Hartree–Fock SCF-MO (HFMO) method was investigated using the best fragmentation pattern of (−)-epicatechin gallate. In the lower energy region (<23.06 kcal mol−1 from the minimum), the average ΔE at each grid point was 1.1 kcal mol−1. The FMO method is applicable to quantum MD calculation of large molecular system at around the standard temperature.
  • Nataša Pejic, Slavica Blagojevic, Jana Vukelic, Ljiljana Kolar- ...
    2007 Volume 80 Issue 10 Pages 1942-1948
    Published: October 15, 2007
    Released: October 12, 2007
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    A pulse perturbation technique was applied to the Bray–Liebhafsky (BL) oscillatory reaction system in a stable nonequilibrium stationary state close to the bifurcation point, to determine micro-quantitatively 6-O-acetylmorphine (6-O-AM). The proposed method, in optimized reaction conditions ([KIO3]0 = 5.9×10−2 M, [H2SO4]0 = 5.5×10−2 M, and [H2O2]0 = 2.0×10−1 M, jo=2.95×10−2 min−1, and T=42.9 °C), relied on the linear relationship between maximal potential shift, ΔEm, caused by perturbation, and the logarithm of the amount of 6-O-acetylmorphine. The method had a rather good sample throughput of 40 samples h−1 with the sensitivity determined to be 0.9 μg mL−1 and the precision RSD = 1.8%. The proposed method was successfully applied to the quantitative determination of 6-O-AM in a real seized street drug sample. The obtained result agrees with those obtained by HPLC. There was no interference from structurally related and associated compounds, such as papaverin, noscapin, and heroin.
  • Makoto Handa, Koji Murakoshi, Atsushi Nishikawa, Koji Yahata, Kimie Sh ...
    2007 Volume 80 Issue 10 Pages 1949-1954
    Published: October 15, 2007
    Released: October 12, 2007
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    Dinuclear and tetranuclear copper(II) complexes with a ligand bearing phthalocyanine and Schiff-base coordination sites were prepared and characterized. The dinuclear complex has two copper(II) phthalocyanine units linked by 2,6-diiminomethyl-4-methylphenol. The imino nitrogen (Schiff-base) coordinates to two more copper(II) ions to give a tetranuclear copper(II) complex composed of a hydroxo- and phenoxo-bridged copper(II) dinuclear unit and two copper(II) phthalocyanine units. Magnetic, spectroscopic, and electrochemical studies showed that there is no significant interaction among the two copper(II) phthalocyanine units and the hydroxo- and phenoxo-bridged dinuclear unit.
  • Chika Bando, Atsushi Furukawa, Kiyoshi Tsuge, Kazumi Takaishi, Yoichi ...
    2007 Volume 80 Issue 10 Pages 1955-1964
    Published: October 15, 2007
    Released: October 12, 2007
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    Carbonyl-coordinated ruthenium(II) and osmium(II) porphyrin dimers bridged with aza ligands, [{M(por)(CO)}2](BL), (M = RuII, OsII; por = ttp (5,10,15,20-tetra-p-tolylporphyrinato dianion), oep (2,3,7,8,12,13,17,18-octaethylporphyrinato dianion); BL = pz (pyrazine), bpy (4,4′-bipyridine), dabco (1,4-diazabicyclo[2,2,2]octane)), were prepared and characterized, and their structures were determined by using single-crystal X-ray crystallography. The metal–metal distances of the pz-, bpy-, and dabco-bridged dimers in [{M(por)(CO)}2(BL)] were about 7.1–7.3, 11.5, and 7.3–7.4 Å, respectively. From electrochemical measurements, the first oxidation waves of the ruthenium and osmium porphyrin dimers with the pz and dabco, except the Ru–oep systems, were split, although the first oxidation in the Ru complexes occurs at the porphyrin rings and in the Os complexes occurs at the metal centers. The extent of the potential splits at the first oxidation processes, which reflects magnitude of the intramolecular redox interactions, was in the orders: ttp > oep and Os (metal oxidation) > Ru (ring oxidation), and dabco ≥ pz >> bpy.
  • Yoshitaka Sakai, Shoko Yoshida, Takeshi Hasegawa, Hideyuki Murakami, K ...
    2007 Volume 80 Issue 10 Pages 1965-1974
    Published: October 15, 2007
    Released: October 12, 2007
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    Preparation and structural characterization of giant “tetrapod”-shaped polyoxometalates (POMs) with approximately Td symmetry, [{α-P2W15Ti3O59(OH)3}43-Ti(H2O)3}4X]21− (X=Br (1a), I (2a), and NO3 (3a)), consisting of four tri-titanium(IV)-substituted α-Dawson subunits, four octahedral Ti(H2O)3 bridging groups and one encapsulated anion X, are described. Sodium salts of three giant “tetrapod”-shaped POMs encapsulating different anions 13 were prepared as analytically pure crystals in 1:5 molar-ratio reactions in water of the tri-lacunary Dawson POM with the in situ-generated “TiX4” (X=Br, I, and NO3), which were prepared by the reactions of Ti(SO4)2 with BaX2 in aqueous solution [Note: The polyoxoanion is represented by 1a, 2a, 3a, …, and the whole formula, which contains counter ions, polyoxoanion, hydrated waters, and so on, is represented by 1, 2, 3, …]. The compounds were characterized by using elemental analysis, thermogravimetric and differential thermal analyses (TG/DTA), solid-state and solution IR, solid-state and solution 31P NMR spectroscopy, and X-ray crystallography. Molecular structures of 1a3a are analogous to the previously prepared POM with X=Cl (4a). The fact that encapsulation of the different anions (Cl, Br, I, and NO3) was achieved in the central cavity of the giant “tetrapod”-shaped POM shows the cationic character of the central framework constituted by the protonated Ti–O–Ti bonds, i.e., the Ti–OH–Ti bonds. The solid-state and solution 31P NMR measurements showed that 1a3a were stable in the solid-state and in DMSO, but in water, they partially decomposed. These properties of 1a3a in water are in contrast to that of 4a.
  • Vasi Ahmed Ebrahim Shaikh, Shrikant Vitthal Lonikar, Deepa Arun Dhobal ...
    2007 Volume 80 Issue 10 Pages 1975-1980
    Published: October 15, 2007
    Released: October 12, 2007
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    Liquid-crystalline derivative of β-cyclodextrin (BCD) was prepared by covalent linking of monocholesteryl succinate (ChMS) with β-cyclodextrin. To the best of our knowledge, this was first ever attempt so far of its kind, in which BCD has been converted into its liquid-crystalline derivative through covalent linkage of a mesogen. The degree of substitution (DS) obtained was ≈2.00. The product was characterized by various techniques, such as FT-IR, NMR, DSC, hot-stage-coupled optical polarizing microscopy (OPM), microanalysis and chemical methods. Cholesterol-linked β-cyclodextrin (CDCh) derivative was found to exhibit thermotropic liquid-crystalline behavior. The product exhibited birefringence during first heating above 130 °C, and it became isotropic at about 180 °C, whereas the parent compound BCD decomposed without melting above 250 °C. A comparison of CDCh derivative to similar liquid-crystalline polysaccharide derivatives is presented.
  • Hajime Ito, Tsuyoshi Maeda, Masaya Sawamura
    2007 Volume 80 Issue 10 Pages 1981-1986
    Published: October 15, 2007
    Released: October 12, 2007
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    A new tetranuclear platinum(II) metallamacrocycle, including four 1,3-diisocyanoarene ligands, was synthesized and characterized. The reaction of PtI2(cod) with an equimolar amount of the 1,3-diisocyanoarene ligand in dichloromethane under diluted conditions gave the metallamacrocycle [(PtI2)4(1,3-diisocyanoarene)4]. X-ray crystallographic analysis showed that the complex adopted a square ring structure with trans arrangement of coordinated isocyanides around the Pt atoms. GPC, ESI-MS, IR, and NMR analysis of the metallamacrocycle showed that the tetranuclear macrocyclic scaffold was maintained in solution.
  • Hisae Karimata, Shu-ichi Nakano, Naoki Sugimoto
    2007 Volume 80 Issue 10 Pages 1987-1994
    Published: October 15, 2007
    Released: October 12, 2007
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    Although the thermodynamic stability of ordered DNA is known to be affected by interactions with cations and water molecules, there is scarce quantitative information about the behavior of DNA under conditions of molecular crowding as found inside the cell. In this study, we measured the thermal stability of DNA base pairs under conditions of molecular crowding caused by polyethylene glycol (PEG) and at different concentrations of NaCl. Even though PEG 200 and 8000 (average molecular weights of 200 and 8000, respectively) decreased the stability of DNA base pairs at high NaCl concentrations, PEG 8000 substantially increased the stability at low NaCl concentrations. Quantitative analyses of the thermodynamic parameters made it possible to determine the numbers of water molecules (−Δnw) and sodium ions (−ΔnNa+) bound to the hairpin DNA. These measurements showed that PEG decreased the −ΔnNa+ value without changing the −Δnw value, suggesting that PEG buffers sodium ion binding but may not affect the hydration status of the nucleotide or sodium ion. These results should help clarify the effects of molecular crowding on DNA stability and function and provide quantitative information about the effects of molecular crowding in cells and on chips and nanoparticles.
  • Nao Yoshimura, Atsuya Momotake, Yoshihiro Shinohara, Yoshinobu Nishimu ...
    2007 Volume 80 Issue 10 Pages 1995-2000
    Published: October 15, 2007
    Released: October 12, 2007
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    Dendrimers with enediynes at the core and a benzyl ether-type dendron at the surrounding periphery were prepared as pure cis- and trans-isomers. Intramolecular energy-transfer efficiency and emission properties as well as photoisomerization around the C=C double bond were studied.
  • Krištof Kranjc, Marijan Kocevar
    2007 Volume 80 Issue 10 Pages 2001-2007
    Published: October 15, 2007
    Released: October 12, 2007
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    An efficient, green access to polysubstituted and highly constrained bicyclo[2.2.2]octenes via a microwave-assisted cycloaddition reaction is described. The double Diels–Alder reaction of a series of 2H-pyran-2-ones with N-substituted maleimides was investigated under different reaction conditions: neat and in the presence of a minor amount of a liquid additive. A comparison of the different conditions showed the advantage of the presence of a minor amount of butan-1-ol in the otherwise neat reaction mixture.
  • Lili Cheng, Carlin Aw, Siew Siang Ong, Yixin Lu
    2007 Volume 80 Issue 10 Pages 2008-2010
    Published: October 15, 2007
    Released: October 12, 2007
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    Various alkyl ethers were efficiently cleaved by treating them with pyridinium halides in ionic liquid, and the desired products were obtained in excellent yields.
  • Shinya Nagano, Siddiki S. M. A. Hakim, Takashi Sugimura
    2007 Volume 80 Issue 10 Pages 2011-2013
    Published: October 15, 2007
    Released: October 12, 2007
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    Two units of acrylate or methacrylate were connected with 2,4-pentanediol. Michael addition of organometallic compounds to this substrate failed to cause the intended intramolecular Michael addition of the generated enolate, but the addition of carbon radical induced the internal addition to give cyclic compounds in yields up to 79%.
  • Takeshi Itakura, Ryo Sasai, Hideaki Itoh
    2007 Volume 80 Issue 10 Pages 2014-2018
    Published: October 15, 2007
    Released: October 12, 2007
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    Detoxification of polluted water and resource recovery of boron and fluorine by using a sampling-type hydrothermal mineralization treatment apparatus was investigated. The hydrothermal mineralization treatment is a geomimetic treatment, which recovers natural minerals from aqueous media under hydrothermal conditions. As a result, hydrothermal mineralization treatment for aqueous solutions containing borate or fluoroborate ions, followed by separation of the reaction solution from precipitate, effectively reduced boron and fluorine concentration in solution, and parasibirskite (Ca2B2O5·H2O) and fluorite (CaF2) formed in high yields. Both the boron and fluorine concentration after the treatment for 2 h at 150 °C was 4 mg dm−3 regardless of its initial concentration (5–3000 mg dm−3) and the ionic species (B(OH)4 or BF4). Therefore, the hydrothermal mineralization treatment by using a sampling-type apparatus should be an effective method to detoxify the wastewater and ground water containing these ions and recover these ions as reusable mineral.
  • Ichiro Tanahashi
    2007 Volume 80 Issue 10 Pages 2019-2023
    Published: October 15, 2007
    Released: October 12, 2007
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    Photocatalytic deposition of Ag nanoparticles from AgNO3 aqueous solution onto TiO2 films (Ag/TiO2 films) was carried out by using ultraviolet light irradiation at room temperature. The Ag/TiO2 films were characterized by XRD, XPS, and SEM. The mean diameter of Ag nanoparticles on the film was estimated to be 113 nm. In the optical absorption spectra of the Ag/TiO2 film, the localized surface plasmon resonance (LSPR) peak of Ag nanoparticles was observed around 390 nm. A linear relation was clearly observed between the LSPR peak wavelength and the refractive index of the surrounding media, such as alcohols, D-glucose and urea aqueous solutions, in the range of 1.0003–1.4394. The Ag/TiO2 films were easy to prepare and had a reproducible SPR sensing performance.
  • Masaharu Tsuji, Nobuhiro Miyamae, Michiko Nishio, Sachie Hikino, Naoki ...
    2007 Volume 80 Issue 10 Pages 2024-2038
    Published: October 15, 2007
    Released: October 12, 2007
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    Shape- and size-controlled synthesis of gold nanocrystals was studied by using a microwave–polyol method in the presence of Au seeds and poly(vinylpyrrolidone) (PVP) as a polymer surfactant. Mixtures of spherical, triangular, hexagonal, octahedral, and decahedaral particles were prepared as Au seeds by reducing Au3+ in AuCl4 in ethylene glycol (EG). When Au nanoparticles were prepared from AuCl4/Cl/PVP/EG solutions by using these Au seeds, significant changes in shapes and sizes of the Au seeds occurred. Such changes depended strongly on the concentrations of AuCl4 and Cl. Large single-twin plate-like particles and multiple-twin decahedral particles were the major products at high concentrations of AuCl4, whereas icosahedral particles were preferentially produced at high Cl concentrations. It should be noted that the octahedral and spherical particles involved in the Au seeds were completely dissolved at high AuCl4 and Cl concentrations. The significant changes in shapes and sizes of Au nanoparticles could be explained by the oxidative etching of the Au seeds by AuCl4 + Cl anions in the range of 60–160 °C and crystal growth of specific shapes of Au nanocrystals in the range of 160–198 °C on the basis of changes in color and UV–vis–NIR spectra of solutions and TEM images of products during etching.
  • Hideharu Iwakuni, Yusuke Shinmyou, Hiroshige Matsumoto, Tatsumi Ishiha ...
    2007 Volume 80 Issue 10 Pages 2039-2046
    Published: October 15, 2007
    Released: October 12, 2007
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    NO direct decomposition on doped SrFeO3 perovskite oxide was investigated. The ability of SrFeO3 for direct decomposition of NO is strongly affected by the dopant in Fe sites. Among the examined dopants and compositions, the highest yield of N2 was achieved on SrFe0.7Mg0.3O3. When SrFe0.7Mg0.3O3 was loaded with Pt, the N2 yield further improved, and the light-off temperature fell by 100 K. On this catalyst, the yields of N2 and O2 were 56 and 35%, respectively, at 1123 K. On the Pt-loaded SrFe0.7Mg0.3O3 catalyst, the NO decomposition rate increased with increase in the NO partial pressure with PNO1.31. The presence of oxygen slightly decreased the N2 yield with PO2−0.12. Therefore, the effect of oxygen poisoning on NO decomposition upon Pt-loaded SrFe0.7Mg0.3O3 is small. From the result of O2-TPD, Pt loading possibly weakens the adsorption strength of surface oxygen and enhances NO adsorption. In summary, this study shows that the substitution of Fe with lower valence cation in SrFeO3 and also loading a small amount of Pt are highly effective for increasing the NO decomposition activity.
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