Bulletin of the Chemical Society of Japan
Online ISSN : 1348-0634
Print ISSN : 0009-2673
ISSN-L : 0009-2673
Volume 86, Issue 1
Displaying 1-20 of 20 articles from this issue
Award Accounts
The Chemical Society of Japan Award for Creative Work for 2010
  • Tetsu Tatsuma
    2013 Volume 86 Issue 1 Pages 1-9
    Published: January 15, 2013
    Released on J-STAGE: January 15, 2013
    Advance online publication: December 25, 2012
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    Plasmonic metal nanoparticles absorb and scatter visible light due to localized surface plasmon resonance (LSPR). The optical properties including resonance wavelength and absorption intensity depend on particle size, shape, orientation, spacing, and dielectric environments. If silver nanoparticles are placed on TiO2, plasmonic excitation of the particles by visible or near-infrared light results in their oxidation due to plasmon-induced charge separation. Silver ions thus released are reduced back to silver nanoparticles by UV-excitation of TiO2. These pseudo-reversible processes induced by visible and UV light between silver nanoparticles and silver ions are applied to various photoelectrochemical devices and materials. Multicolor photochromism is a typical example, in which an ensemble of silver nanoparticles on TiO2 is colored by monochromated light to a color corresponding to the excitation wavelength. The use of silver nanorods allows infrared and polarization photochromism. The photoinduced oxidation is also applied to size, shape, and orientation control of silver nanoparticles. A photomorphing gel is an additional application of the reversible processes.
    Plasmonic silver nanoparticles on TiO2 are oxidized to silver ions by visible or infrared light, and reduced back by UV light. The pseudo-reversible system is applied to visible and infrared multicolor photochromism, hydrogel photomorphing, and morphology control of nanoparticles. Fullsize Image
     
The Chemical Society of Japan Award for Young Chemists for 2011
  • Masato Ikeda
    2013 Volume 86 Issue 1 Pages 10-24
    Published: January 15, 2013
    Released on J-STAGE: January 15, 2013
    Advance online publication: December 25, 2012
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    In biological systems, noncovalent interactions of molecular building blocks such as lipids, proteins, and nucleic acids play important roles in creating diverse complex structure and dynamic function. Inspired by such biological systems, we have designed a variety of functional supramolecular materials on the basis of self-assembly of covalently prefabricated small molecules. Among them, the following three topics are described in this account: (1) supramolecular self-assembled materials based on π-conjugated disk-shaped molecules, (2) supramolecular materials based on helical-shaped molecules, and (3) biofunctions of supramolecular materials based on amphiphilic molecules.
    Inspired by elaborate biological systems, a variety of functional supramolecular materials on the basis of noncovalent self-assembly of covalently prefabricated small molecules are designed and constructed. Fullsize Image
     
BCSJ Award Article
  • Yasuko Osakada, Kiyohiko Kawai, Tetsuro Majima
    2013 Volume 86 Issue 1 Pages 25-30
    Published: January 15, 2013
    Released on J-STAGE: January 15, 2013
    Advance online publication: December 25, 2012
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    Charge transfer (CT) in DNA has been studied extensively in the past decade. Several reasonable models, concerning delocalized charge over guanines (G’s) as well as localized charge on individual G’s, such as polaron and hopping mechanisms, are proposed based on theoretical and experimental research. It is likely that the dynamic nature of DNA such as electronic coupling and dynamic motion is important to promote this process. We previously reported the kinetic features of CT across the G and cytosine (C) repetitive sequence (GC repeats). Temperature-dependent experiments in GC repeats suggested the importance of the conformational flexibility and structure of DNA toward CT in DNA. In the present paper, we look further into the dynamic mechanisms of CT in DNA across GC repeats. Based on the nanosecond transient absorption measurement, we monitored the migration of a charge in DNA having GC repeats separated by A/T intervening base pair(s). Interestingly, the migration time of the charge varies depending on the position, where A/T base pair(s) are located among GC repeats. Thus, the data obtained here are not simply explained by G-hopping mechanisms, in which the charge localizes on individual G’s. These results possibly indicate that CT in DNA across GC repeats proceeds via delocalization of the charge over G’s to some extent, rather than localized G-hopping mechanisms.
    Herein, we investigated the kinetics of charge transfer (CT) through DNA across guanine (G)–cytosine (C) repeats intervened by adenine–thymine base pair(s), suggesting that CT in DNA across GC repeats possibly proceeds via delocalization of the charge over G’s to some extent. Fullsize Image
     
 
  • Israfil I. Guseinov, Nursen Seçkin Görgün
    2013 Volume 86 Issue 1 Pages 31-36
    Published: January 15, 2013
    Released on J-STAGE: January 15, 2013
    Advance online publication: December 29, 2012
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    With the use of one-range addition theorems of Slater type orbitals (STOs) introduced by one of the authors, three-center nuclear attraction integrals containing Coulomb–Yukawa like correlated interaction potentials (C-CIPs and Y-CIPs) appearing in the Hartree–Fock–Roothaan (HFR) equations for molecules are evaluated. These integrals are expressed through the overlap integrals which depend on the frictional quantum number α, where −∞ < α ≤ 2. The convergence of the series is tested by calculating three-center nuclear attraction integrals of C-CIPs, Y-CIPs, and STOs for the arbitrary values of potential parameters and locations of orbitals. For rapid calculations of these integrals, we use the partial summations of some indices corresponding to progressively increasing upper limits appearing in the series expansion relations. Additionally, the binomial coefficients arising in the series are stored in the memory of the computer using their recurrence relation. The fast and accurate computation approach suggested in this work is demonstrated.
  • Akira Hafuka, Hiroki Taniyama, Sang-Hyun Son, Koji Yamada, Masahiro Ta ...
    2013 Volume 86 Issue 1 Pages 37-44
    Published: January 15, 2013
    Released on J-STAGE: January 15, 2013
    Advance online publication: December 29, 2012
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    Supplementary material
    Two novel asymmetric BODIPY fluoroionophores with dipicolylamine (BDP-DPA, dipicolylamine: bis(pyridylmethyl)) and terpyridine (BDP-TPY) are described. These fluoroionophores display opposite wavelength responses on complexation with heavy metal ions. Furthermore, the fluorescence spectra vary depending on the ionic species. In particular, BDP-DPA shows a high affinity toward Cr3+ and upon complexation, the fluorescence spectrum blue-shifts from 591 to 566 nm. In contrast, BDP-TPY preferentially binds to Zn2+ and the fluorescence spectra red-shifts from 539 to 567 nm. BDP-TPY is the first example of asymmetric BODIPY with a pyridyl receptor at the 3 position showing red-shifted fluorescence by complexation with metal ions. The concentration of each metal ion was successfully determined by ratiometric measurement. The wavelength-responses characteristics of these fluoroionophores could be very useful in the development of novel ratiometric fluoroionophores for metal ions.
  • Yasunori Inoue, Mayo Sugano, Shunsuke Kawakami, Masaaki Kitano, Kiyota ...
    2013 Volume 86 Issue 1 Pages 45-50
    Published: January 15, 2013
    Released on J-STAGE: January 15, 2013
    Advance online publication: December 15, 2012
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    Supplementary material
    An amorphous carbon (a-C) semiconductor was prepared by the pyrolysis of naphthalene in the presence of AlCl3 under a nitrogen gas flow. Electrical properties, such as the Seebeck coefficient (S) and electrical conductivity (σ), of the a-C materials were studied as a function of the heat treatment temperature (773–1273 K) and time (5–30 h). The electrical conductivity of a-C increased with the heating temperature. At a heating temperature of 873 K, a-C exhibits p-type semiconducting behavior (S = 0.41 mV K−1, σ = 2.0 × 10−5 S cm−1) and consists of a mixture of sp2-bonded carbon sheets (average sheet size: ca. 1.0 nm) and polycyclic aromatic hydrocarbons (PAH). After prolonged heat treatment (30 h) at 873 K, the electrical conductivity of a-C was increased by a factor of approximately 50 without loss of the semiconductivity (S = 0.20 mV K−1, σ = 9.6 × 10−4 S cm−1). The increase in the electrical conductivity of a-C is attributed to the decomposition of insulating PAH compounds by the prolonged heat treatment. Thus, precise control of the heating temperature and time has a significant effect on the p-type semiconductivity and electrical conductivity of a-C materials.
  • Yoshinori Aoyama, Kouji Hatakeyama, Takuma Mukai, Hitoshi Koizumi
    2013 Volume 86 Issue 1 Pages 51-56
    Published: January 15, 2013
    Released on J-STAGE: January 15, 2013
    Advance online publication: January 10, 2013
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    Poly(3-alkylthiophene) (P3AT) with alkyl side chains longer than or equal to butyl is soluble in some solvents and fusible. However, conductive states of P3AT are unstable. In order to develop soluble conductive polymers with a stable conductive state, electronic properties of poly[3-(1,1-dimethylpropyl)thiophene] (P3DMPT) and poly(3-cyclohexylthiophene) (P3cHT) were compared with those of poly(3-octylthiophene) (P3OT). The photoabsorption spectrum of P3DMPT did not change before and after doping with NOBF4. This is due to its high oxidation potential. The oxidation peak in the cyclic voltammogram of P3DMPT was 1.65 V vs. Ag/Ag+, which is too high to be doped with NOBF4. Polaron peaks were observed after the doping of P3cHT. The polarons of P3cHT decayed faster than those of P3OT with time. However, the behavior of the electron spin resonance spectrum of P3cHT was different from that of P3OT: the spin concentration of P3cHT decreased, whereas the spin concentration of P3OT increased with time. The conductive state of P3cHT will decay through different mechanism of P3OT: their dedoping will be a reverse process of doping. The reverse dedoping processes of P3cHT will be due to the high oxidation potentials of P3cHT.
  • Pooja Maheshwari, Raakhi Gupta, Moritz von Hopffgarten, Raj K. Bansal
    2013 Volume 86 Issue 1 Pages 57-66
    Published: January 15, 2013
    Released on J-STAGE: January 15, 2013
    Advance online publication: December 29, 2012
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    Supplementary material
    A comparative study of the DFT calculations with and without dispersion correction for the determination of the relative activation energy barriers and reaction energies of the normal electron demand Diels–Alder (NED DA) reactions of imidazo[1,2-a]pyridine and its derivatives with 1,3-butadiene at the B3LYP/6-31+G** level reveals that on inclusion of the dispersion correction, the relative activation energy barriers are lowered by ca. 10–13 kcal mol−1 whereas relative reaction energies are increased by ca. 9–13 kcal mol−1 as compared to the DFT calculations without dispersion correction. Similar results are obtained for the reverse electron demand (RED) DA reactions of imidazo[1,2-a]pyridine and its derivatives with tetrachloro-o-benzoquinone. The relative free energies of solvation of different species determined from SCRF calculations allow to detect solvent-induced geometry relaxation of the reactant molecules and the transition states which rationalises lowering of the relative activation energies in methylene chloride. The reactions are found to occur without the involvement of the reactants complexes.
  • Patchreenart Saparpakorn, Masato Kobayashi, Hiromi Nakai
    2013 Volume 86 Issue 1 Pages 67-74
    Published: January 15, 2013
    Released on J-STAGE: January 15, 2013
    Advance online publication: December 25, 2012
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    Supplementary material
    An effective tripeptide inhibitor, 2-naphthoyl–Lys–Lys–Arg–H (Naph-KKR-H), acts as an inhibitor against West Nile Virus (WNV) NS3 protease (NS3pro). Two conformations of Naph-KKR-H were found in the crystal structure of WNV NS2B cofactor and NS3pro. In this study, divide-and-conquer-based density functional theory and second-order Møller–Plesset perturbation theory calculations were applied in order to clarify the binding mechanism of both conformations. The solvent effect was also examined. In addition, bond energy density analysis (BEDA) was performed to investigate the binding interaction. Interestingly, even though conformations 1 and 2 revealed the difference of interaction energies, energy barriers, reaction energies, and type of reaction, the energy differences of tetrahedral intermediate forms as compared to their separated systems were close to each other with the energy difference of ca. 4 kcal mol−1. These results clearly indicated why both conformations existed in the crystal structure. The bond energy also showed the important interaction to the amino acids and role of water molecules in the active site. Furthermore, according to the high correlation between the changes of bond distance and bond energy, it was found that the BEDA technique is useful to study the binding mechanism.
  • Kenta Motobayashi, Satoshi Katano, Yousoo Kim, Maki Kawai
    2013 Volume 86 Issue 1 Pages 75-79
    Published: January 15, 2013
    Released on J-STAGE: January 15, 2013
    Advance online publication: December 25, 2012
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    Supplementary material
    We demonstrate the spectral fitting analysis of action spectroscopy with a scanning tunneling microscope (STM-AS) that enables us to determine the existence of two vibrational modes that overlap in energy and also the modes which exist in lower energy region than the actually observed spectral region. These hidden properties obtained only by spectral fitting are essential for the quantitative understanding of the action spectra. The assignment of vibrational signals in the analysis follows the approximate rule of which vibrational mode is active in STM-AS that was previously proposed based on the resonant tunneling model and supporting experimental results.
  • Keiichi Mitsuta
    2013 Volume 86 Issue 1 Pages 80-98
    Published: January 15, 2013
    Released on J-STAGE: January 15, 2013
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    Though reported in 1973 by Sawada and Yamazaki, the experimental data obtained from kinetic competition between cytochrome c reduction due to superoxide and spontaneous dismutation of superoxide have long been disregarded because of disagreement with the experimental values obtained from pulse radiolysis. Assuming that the cause of this disagreement could be explained as being an acceleration of the dismutation rate due to the superoxide dismutase (SOD)-like activity possessed by xanthine oxidase (XOD), the value of the rate constant, kXOD, for the reaction between XOD and superoxide that was considered necessary to explain their experimental findings was calculated. As a result, the values of kXOD have been found to be 3.0 × 106 (pH 5), 4.4 × 106 (pH 5.5), 5.5 × 106 (pH 7), 3.6 × 106 (pH 7.8), and 9.2 × 105 (pH 8.5) in M−1 s−1. These values are good matches for two previous experimental values, 2.1 × 106 (pH 7.8) and 8.0 × 105 (pH 12) in M−1 s−1, obtained from the present author’s ESR spin-trapping experiments, and are considered to show the overall image of the SOD-like function acquired by XOD in the long course of its molecular evolution.
  • Yasuo Kameda, Hiroshi Deguchi, Yoshiyuki Kubota, Hirotoshi Furukawa, Y ...
    2013 Volume 86 Issue 1 Pages 99-103
    Published: January 15, 2013
    Released on J-STAGE: January 15, 2013
    Advance online publication: December 29, 2012
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    High-energy X-ray diffraction measurements were carried out for liquid 2-aminoethanol (NH2CH2CH2OH, MEA) in order to obtain direct information on the conformation of MEA in the liquid state, in which competition between intra- and intermolecular hydrogen bonds might occur. Least-squares fitting analysis was applied to the high-Q region of the observed total interference term with excellent statistical accuracies. Independent parameters, the C–C, C–O, and C–N interatomic distances, bond angles, ∠OCC and ∠CCN, and a dihedral angle ∠(NCC)–(CCO), were successfully obtained. It has been concluded that the MEA molecule takes the gauche conformation with the dihedral angle ∠(NCC)–(CCO) = 53(3)°, suggesting the formation of the intramolecular hydrogen bond is dominant in the liquid state.
  • Takuya Miyazaki, Yasuo Kameda, Yuko Amo, Takeshi Usuki
    2013 Volume 86 Issue 1 Pages 104-111
    Published: January 15, 2013
    Released on J-STAGE: January 15, 2013
    Advance online publication: December 29, 2012
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    Neutron diffraction with 14N/15N, 35Cl/37Cl, and 6Li/7Li isotopic substitution methods have been applied to aqueous 10 mol % urea solutions involving 5 mol % NaCl and 10 mol % LiCl, in order to obtain information on the hydration structure around the amino group of urea which is affected by coexisting ions, Cl and Li+. Observed first-order difference functions, ΔNinter(Q), ΔCl(Q), and ΔLi(Q), were respectively analyzed using least-squares fitting. The nearest neighbor intermolecular N···Ow (Ow: oxygen atom in D2O) distance was determined to be 3.09(1) and 3.19(1) Å, from the analyses for sample solutions involving NaCl and LiCl, respectively. These intermolecular N···Ow distances are slightly longer than those reported for aqueous urea solutions of similar concentrations. These results suggest that hydrogen bonds among amino groups of urea and neighboring water molecules are weakened by coexisting alkali metal salts. The structural parameters concerning the first hydration shell of Cl and Li+, have been determined to be r(Cl···Dw) = 2.27(1) Å (Dw: deuterium atom in D2O) and r(Li+···Ow) = 1.95(1) Å, respectively. The results indicate that the structure of the first hydration shell around Cl and Li+ is not affected by the presence of urea molecules in the aqueous solution.
  • Kazuki Sato, Yoko Yamaguchi, Ukon Nagai
    2013 Volume 86 Issue 1 Pages 112-120
    Published: January 15, 2013
    Released on J-STAGE: January 15, 2013
    Advance online publication: December 25, 2012
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    Based on the β-turn preference of tetrapeptide sequences as analyzed by CD spectra of their chromophoric derivatives, 10 analogs of gramicidin S (GS) were designed and synthesized with general formula cyclo(–D-Leu1,1′D-Lys2,2′D-Leu3,3′L-Pro4,4′–X5,5′–)2, where X is L-Asn, L-Ala, L-Leu, L-Phe, L-cyclohexylalanine, Gly, D-Ala, D-Leu, D-Phe, or D-cyclohexylalanine. Several analogs with high hydrophobicity showed antibiotic activity as strong as GS. CD spectra of the analogs with D-amino acid or Gly at the X position and their dinitrophenyl derivatives suggested that they have β-sheet conformation that is antipodal to that of GS.
  • Mai Yamamoto, Tomoko Horibe, Yoshiaki Nishisaka, Shuichi Suzuki, Masat ...
    2013 Volume 86 Issue 1 Pages 121-128
    Published: January 15, 2013
    Released on J-STAGE: January 15, 2013
    Advance online publication: January 10, 2013
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    Supplementary material
    The reassociation of carotenoids with the photosynthetic light-harvesting 1 (LH1) pigment–protein complex has proven to be a powerful technique to investigate the function of carotenoids. We have recently investigated the reassociation of the carotenoids, spirilloxanthin (number of conjugated C=C bonds (n) = 13), anhydrorhodovibrin (n = 12), rhodopin (n = 11), and spheroidene (n = 10)) with carotenoid-depleted LH1 subunits isolated from Rhodospirillum rubrum. In the case of the rhodopin complex, small anomalies were observed in the absorption maximum of the Qy band of bacteriochlorophyll a (BChl a Qy) and the singlet–singlet energy-transter efficiency of 1carotenoid*1BChl a* within the LH1–carotenoid complex. The reason for these anomalies could probably be ascribed to the rhodopin hydroxy group. To investigate this further, reassociation experiments of the LH1 complex with hydroxy-protected rhodopin, all-trans-3,4-dihydroanhydrorhodovibrin (1), were conducted. We observed a normal absorption maximum (883 nm) of the BChl a Qy band in the LH1–1 complex. The energy-transter efficiency of 1carotenoid* (11*) → 1BChl a* was found to be 53%, giving a good correlation with the other carotenoids. Furthermore, we found a preferential complexation of all-trans-1 to carotenoid-depleted LH1 from a 1:1 mixture of all-trans-1 and cis-1 (cis-1 consists of a 1:1 mixture of 5-cis-5′-trans-1 and 5-trans-5′-cis-1).
  • Juzo Oyamada, Mariko Sakai, Yasunori Yamada, Tsugio Kitamura
    2013 Volume 86 Issue 1 Pages 129-137
    Published: January 15, 2013
    Released on J-STAGE: January 15, 2013
    Advance online publication: December 15, 2012
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    Supplementary material
    The reaction of mesitylene with ethyl propiolate in the presence of [Pd(dppe)(OAc)2] in TFA at 30 °C for 5 h gave diethyl (2E,4Z)-4-[(2,4,6-trimethylphenyl)methylene]-2-pentenedioate selectively. Screening several bidentate phosphines ligands showed that dppe and dppm ligands are good for the arylbutadiene formation. This reaction was applied to other electron-rich arenes and found to be effective for synthesis of arylbutadienes and extended π-conjugated molecules. The regio- and stereoselective addition of an arene to propiolate was confirmed by NMR and single-crystal X-ray structural analyses of the products, suggesting that the arylbutadiene formation consisted of anti addition of an arene and a metal to the triple bond of ethyl propiolate, followed by syn addition to another molecule of ethyl propiolate. Similarly, the reaction of various arenes with ethyl propiolate in the presence of [Pt(dppe)(OTf)2] catalyst gave arylbutadienes selectively. In the Pd- or Pt-catalyzed reaction of arenes with ethyl propiolate, it was found that a bidentate ligand controlled the reaction to lead the formation of arylbutadienes.
  • Takuya Tsuya, Tetsuo Iwanaga, Shinji Toyota
    2013 Volume 86 Issue 1 Pages 138-145
    Published: January 15, 2013
    Released on J-STAGE: January 15, 2013
    Advance online publication: December 29, 2012
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    Supplementary material
    Anthracene–acetylene cyclic dimers having a methoxy or an ethoxy group at the intra-annular position were synthesized by cross-coupling reactions. DFT calculations suggested that the alkoxy–alkyl groups were perpendicular to the planar rigid framework leading to a chiral structure. The enantiomers were resolved by chiral HPLC and their chiroptical properties were characterized by optical rotation and CD spectral measurements. Their absolute stereochemistries were assigned by the theoretical calculation of CD spectra by using the TDDFT method. Kinetic measurements revealed that the barriers to enantiomerization were 122 and >142 kJ mol−1 for the methoxy and ethoxy compounds, respectively. The structures and stereochemistries are compared with those of intra-annular alkyl derivatives.
  • Indri Badria Adilina, Takayoshi Hara, Nobuyuki Ichikuni, Nobuhiro Kuma ...
    2013 Volume 86 Issue 1 Pages 146-152
    Published: January 15, 2013
    Released on J-STAGE: January 15, 2013
    Advance online publication: January 10, 2013
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    Supplementary material
    A series of Pd-incorporated titanate catalysts (Pd/KSTO) were synthesized by the intercalation of Pd(NO3)2 into layered potassium titanate (KTO), which proceeded via a cation-exchange reaction in molten salts. Perovskite phases of Pd/KSTO for catalysis were synthesized at 600 °C and above, whereas a lepidocrocite-type layered titanate structure, similar to that of the parent KTO, was retained when a lower temperature of 400 °C was used during synthesis. In both cases, the Pd species exists as divalent Pd. The synthesized Pd/KSTO catalysts were then applied to the liquid-phase oxidation of alcohols using molecular oxygen without any additives. The perovskite-type Pd/KSTO catalyst displayed superior activity when compared to that of the lepidocrocite-type, yielding a high turnover number of 800 in the aerobic oxidation of 1-phenylethanol with no loss of catalytic activity after three runs in catalyst recycling experiments.
  • Fumiaki Shima, Koshi Kawakami, Takami Akagi, Eiko Mochizuki, Tetsuya T ...
    2013 Volume 86 Issue 1 Pages 153-158
    Published: January 15, 2013
    Released on J-STAGE: January 15, 2013
    Advance online publication: December 29, 2012
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    The cellular uptake of nanoparticles (NPs) was clearly observed by scanning electron microscopy (SEM) employing an ionic liquid for the first time. The samples did not show charge-up effect without staining, and high contrast images were achieved. Because of these unique properties of the ionic liquid, we could finely observe the cellular uptake of NPs compared with conventional SEM observation method. Moreover, the cells became transparent as the accelerating voltage increased, and the internalized NPs composed of heavy atoms were easily determined. This ionic liquid method provides a simple and short pretreatment procedure and thus is a promising technique for evaluating the cellular uptake of NPs and the intracellular fate of NPs. This method also gives a strategy to observe NPs which are unstable in the dry condition by choosing a suitable ionic liquid.
  • Kazuki Urano, Toshikazu Ohno, Kazuaki Tomono, Kazuo Miyamura
    2013 Volume 86 Issue 1 Pages 159-165
    Published: January 15, 2013
    Released on J-STAGE: January 15, 2013
    Advance online publication: January 10, 2013
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    Indigo dye molecules substituted by hexadecyl (C16IND) and icosyl (C20IND) chains were prepared. Crystallographic analysis revealed that C16IND tends to form lamellar structure constituted of dimers. Scanning tunneling microscopy (STM) also revealed that two-dimensional (2D) lamellar structure constituted of C16IND and C20IND dimers were formed at the surface as in crystal. Two different homochiral domains (λ- or δ-domain) could be distinguished by the relative orientation to underlying substrate, and there was a “mosaic region” composed of a number of small (λ/δ)-grains in the self-assembly. Furthermore, time-dependent STM observation for C20IND showed that the interconversion between grains of opposite chirality proceeded in the mosaic region while frustrated at the boundary between ordered chiral domains of opposite chirality.
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