Bulletin of the Chemical Society of Japan
Online ISSN : 1348-0634
Print ISSN : 0009-2673
ISSN-L : 0009-2673
Volume 74 , Issue 9
Showing 1-28 articles out of 28 articles from the selected issue
  • Osamu Yamauchi, Akira Odani, Shun Hirota
    Type: Accounts
    2001 Volume 74 Issue 9 Pages 1525-1545
    Published: 2001
    Released: November 01, 2002
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    Noncovalent or weak interactions play important roles in molecular recognition and structual organization in chemical and biological systems. Hydrogen bonding and aromatic ring stacking are widely recognized for biomolecules, and these and other types of weak interactions are recently attracting much attention as a clue to understanding the efficiency and specificity of biological reactions. We studied weak interactions around the metal center as factors for mixed ligand (ternary) metal complex formation, molecular recognition, and construction of self-organized structures by potentiometric, spectroscopic, and crystallographic methods. We concluded the electrostatic ligand–ligand interactions within Cu(II) and Pd(II) complexes containing an acidic and a basic amino acid and aromatic ring stacking interactions between the aromatic rings of an aromatic amino acid and a coordinated aromatic ligand such as 2,2′-bipyridine. Selective adduct formation between Pt(II) complexes and uncoordinated mononucleotides were found to occur through stacking and hydrogen bonding. In the systems with aromatic ring stacking, a close metal–aromatic ring contact was revealed in the solid state, and the 195Pt NMR spectra indicated electron density decrease due to stacking. As an extension of such studies, we investigated metalloprotein–charged peptide electrostatic interactions and established the redox partner binding site of plastocyanin and its subtle structural change due to the interactions. The results demonstrated the use of charged oligopeptides as models for the studies on protein–protein binding. Weak interactions between [Cu(arginine)2]2+ and its counterions, such as benzene-1,3-dicarboxylate, led to controlled self-organization of the complex ion, giving crystalline products with handed single-helical or double-helical structures and layer structures, depending on the anions used.
  • Yoshihiro Hayakawa
    Type: Accounts
    2001 Volume 74 Issue 9 Pages 1547-1565
    Published: 2001
    Released: November 01, 2002
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    Several novel methods for reliably carrying out the oligonucleotide synthesis via the phosphoramidite strategy have been developed. The first is the method using allyloxycarbonyl and allyl groups for the protection of nucleoside bases and internucleotide linkages, respectively. These protectors can be cleanly removed under almost neutral conditions with a mixture of an organic Pd(0) complex such as Pd[P(C6H5)3]4 or Pd2[(C6H5CH=CH)2CO]3·CHCl3, and P(C6H5)3 in the presence of a nucleophile such as butylammonium formate, diethylammonium hydrogencarbonate, diethylammonium carbonate, or dimedone. A method for the facile oxidation of nucleoside phosphites to phosphates has been developed; this is performed under non-aqueous and non-basic conditions using 2-butanone peroxide in dichloromethane, t-butyl hydroperoxide in toluene, or bis(trimethylsilyl) peroxide in dichloromethane. The combined use of the N-allyloxycarbonyl/P–O-allyl-protected method and anhydrous/non-basic oxidation is extremely useful for the synthesis of nucleotide derivatives sensitive to moisture and/or bases, producing them in higher yield and at a greater level of purity than the existing methods using acyl or aroyl and cyanoethyl groups for the protection of nucleoside bases and internucleotide linkages, respectively, and iodine in aqueous pyridine for the oxidation. Further, acid/azole complexes serving as highly useful activators of phosphoramidites have been invented. The reagents include imidazolium triflate, N-(phenyl)imidazolium triflate, benzimidazolium triflate, and N-(methyl)benzimidazolium triflate, which allow higher-yield synthesis of oligonucleotides than conventionally employed 1H-tetrazole and related reagents. For example, synthesis of oligoribonucleotides via the allyloxycarbonyl/allyl-protected strategy has been carried out more efficiently using N-(phenyl)imidazolium triflate as a promoter than 5-(ethylthio)-1H-tetrazole, which has been found to be the most effective promoter among those currently available for oligoribonucleotide synthesis. Further, imidazolium triflate has opened the door to the extremely convenient and efficient synthesis of oligodeoxyribonucleotides without nucleoside-base protection. This method is obviously advantageous over N-protected methods because it eliminates tedious operations and the use of superfluous reagents required for the introduction and removal of the N-protecting group; risks of decomposition and loss of product by protection and deprotection are also avoided. Facile liquid-phase preparation of short oligomers has also been developed; this is successfully accomplished using stoichiometric amounts of building blocks by the aid of an equimolar amount of azolium reagent or a catalytic amount of 5-(p-nitrophenyl)-1H-tetrazole. These two methods are beneficial from an economical point of view, particularly in large-scale synthesis.
  • Keisuke Hirano, Satoshi Minakata, Mitsuo Komatsu
    Type: Headline
    2001 Volume 74 Issue 9 Pages 1567-1575
    Published: 2001
    Released: November 01, 2002
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    Novel fluorophores, 6-aryl-3,4-diphenyl-α-pyrones, were synthesized and their spectroscopic properties investigated in the form of evaporated films on plain glass slides, as well as in the solid and solution states. An electron-donating aryl group on the 6-position of the pyrones causes a red-shift in the absorption and fluorescent maxima. In the solid states, they show intense blue-to-orange fluorescence, but not in solution. This unusual fluorescent property is caused by fixing the 6-aryl group of the pyrones, and is the result of molecular packing. These interactions induce a pathway for radiative decay, which is associated with intense fluorescence emission only in the solid state.
  • Masayuki Hata, Yoshinori Hirano, Tyuji Hoshino, Minoru Tsuda
    Type: Article
    Subject area: TP
    2001 Volume 74 Issue 9 Pages 1577-1583
    Published: 2001
    Released: November 01, 2002
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    The atomic level reaction mechanism for N-dealkylation of N,N-dimethylaniline (PhNMe2) by hemoproteins, in which a kinetic hydrogen isotope effect (KHIE) was observed, was investigated by quantum mechanical theoretical calculations. Using quantum mechanical theory, one can determine the primary KHIE by the difference in zero-point vibrational energies on normal vibrational modes which are related to the reaction coordinate of H (D or T) atom abstraction from a C–H (C–D or C–T) bond. On the basis of this idea, we theoretically determined the intramolecular primary KHIE for two cases of hydrogen atom abstraction in N-dealkylation of PhNMe2; i.e., hydrogen atom abstraction from a neutral state and proton abstraction from a cation radical state. When the intramolecular primary KHIE obtained by theoretical calculation was compared with experimental results of the intramolecular KHIE on N-dealkylation of PhNMe2, which was catalyzed by some hemoproteins, it was found that four experimental values can be interpreted only from the primary KHIE. However, many other experimental values can not be interpreted only from the primary KHIE.
  • Shinsaku Fujita
    Type: Article
    Subject area: TP
    2001 Volume 74 Issue 9 Pages 1585-1603
    Published: 2001
    Released: November 01, 2002
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    The sphericity concept proposed for specifying stereochemistry in a molecule (S. Fujita, J. Am. Chem. Soc., 112, 3390 (1990)) has been extended to investigate stereoisomerism among molecules. The new matter of the present approach is to characterize the global symmetries of molecules as the “local symmetries of stereoisomerism”. Thereby, stereochemistry and stereoisomerism have been discussed on a common basis. Promolecules, which have been generated as stereochemical models of molecules by placing proligands (structureless ligands with chirality/achirality) on the vertices of a tetrahedral skeleton, have been analyzed by a permutation-group approach as well as by a point-group one. The skeleton has been considered to belong to the symmetric group of degree 4 (S[4]) as well as to the isomorphic point group Td. The chirality fittingness derived from the sphericity concept has been applied to the characterization of local symmetries of promolecule, where two types of Young’s tableaus have been compared. Thus, Young’s tableaus of symmetry have been introduced to treat the ligand packing based on the chirality fittingness. These tableaus have been compared with Young’s tableaus of permutation, which have taken no account of such chirality fittingness. The two types of Young’s tableaus have been applied to the enumeration of tetrahedral isomers under the observance and the violation of chirality fittingness. This enumeration has enabled us to clarify the quantitative aspect of the sphericity concept in characterizing isomer equivalence. Thereby, equivalent isomers under a point-group symmetry have been shown to construct an orbit of stereoisomers that is ascribed to a coset representation. Homomeric, enantiomeric, and diastereomeric relationships between stereoisomers have been discussed by means of homospheric, enantiospheric and hemispheric orbits of stereoisomers. Skeleton-based and ligand-based categories for enantiomers and diastereomers have been discussed. The stereogenicity and the prostereogenicity of the Chan–Ingold–Prelog system have been related to Young’s tableaus of permutation.
  • Takashi Ishiwata, Takashi Yotsumoto, Satoshi Motohiro
    Type: Article
    Subject area: TP
    2001 Volume 74 Issue 9 Pages 1605-1610
    Published: 2001
    Released: November 01, 2002
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    We used the perturbation-facilitated optical–optical double resonance technique to access the ungerade ion-pair states of I2 using the (1 + 1) photo-excitation sequence through the B3Π(0u+)–c1g parity mixing states. By analyzing the second step of the double resonance to the F0u+(3P0), γ1u(3P2), and H1u(3P1) states, the g–u coupling schemes were elucidated in the intermediate B3Π(0u+)–c1g state. We were also able to populate the δ2u(3P2) state through the g–u mixing state, and to improve its molecular constants. The interference effect between the parallel γ1u(3P2)–c1g and perpendicular δ2u(3P2)–c1g transitions was used to derive the ratio of their electronic transition moments, (μ||e/μe) ∼ 5.5.
  • Shunji Katsumata
    Type: Article
    Subject area: TP
    2001 Volume 74 Issue 9 Pages 1611-1616
    Published: 2001
    Released: November 01, 2002
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    The HeI photoelectron spectra of all-trans-retinal, 13-cis-retinal and 9-cis-retinal have been observed in the gas phase by using an infrared heating device, which was developed in this laboratory. The first four ionization energies (Iobs) of all-trans-retinal have been determined to be 7.55, 8.40, 9.21, and 10.03 eV, and the ionization energies for the other two derivatives were also equal to them within the experimental error. Ab initio calculations were performed to study the optimized structures of neutral and cationic ground states of retinals and to elucidate the valence electronic structures associated with the observed ionization energies. The structural change from the neutral to the cation was considered, and the bond lengths and dihedral angles between the planes of the β-ionone ring and the polyene chain in each of retinals have been determined.
  • Zhong-Ze Gu, Osamu Sato, Yasuaki Einaga, Masahiro Kai, Tomokazu Iyoda, ...
    Type: Article
    Subject area: AI
    2001 Volume 74 Issue 9 Pages 1617-1622
    Published: 2001
    Released: November 01, 2002
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    A new photo-responsive coordination polymer of [Ni(en)2]4[Fe(CN)5NO]2[Fe(CN)6]·6H2O was synthesized. In this compound, Ni–CN–Fe forms one-dimensional standing-wave-like chains, onto which photo-functional groups of pentacyanonitrosylferrate(II) are appended. Photo-irradiation with blue light at less than 200 K transformed the pentacyanonitrosylferrate(II) from the ground state to a metastable state, which could be reverted to the original state by irradiation with red light.
  • Sadayuki Himeno, Hideki Tatewaki, Masato Hashimoto
    Type: Article
    Subject area: AI
    2001 Volume 74 Issue 9 Pages 1623-1628
    Published: 2001
    Released: November 01, 2002
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    A yellow sulfatotungstate complex was formed by heating a 50 mM W(VI)–2 M H2SO4–40% (v/v) CH3CN system at 70 °C for 14 days, being isolated as the tetrapropylammonium (n-Pr4N+) salt. An X-ray structural analysis (ortho-rhombic, Pca21 (No. 29) a = 27.181(1), b = 14.1428(6), c = 27.7292(9) Å, and Z = 4) revealed that the structure consists of an α-Dawson-type [S2W18O62]4− anion. The α-[S2W18O62]4− complex underwent a four-step reversible one-electron reduction in CH3CN, and the presence of acid caused the one-electron waves to be converted into three two-electron waves. The formation conditions were elucidated by a combined Raman and voltammetric study.
  • Kuniharu Miyata, Hitoshi Kanno, Kiyoshi Tomizawa, Yukihiro Yoshimura
    Type: Article
    Subject area: AI
    2001 Volume 74 Issue 9 Pages 1629-1633
    Published: 2001
    Released: November 01, 2002
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    Homogeneous nucleation temperatures (TH’s) of aqueous alkali chloride and acetate solutions were measured as a function of salt concentration. There is a linear relation between TH and 1/r+ (r+: ionic radius of alkali ion) for aqueous alkali chloride solutions. In the supercooling of aqueous alkali acetate solutions, the ionization constant also plays an important role in their supercooling behavior. The TH results were discussed in relation to nucleation theory.
  • Shuji Oishi, Mai Mitsuya, Takaomi Suzuki, Nobuo Ishizawa, Juan Carlos ...
    Type: Article
    Subject area: AI
    2001 Volume 74 Issue 9 Pages 1635-1639
    Published: 2001
    Released: November 01, 2002
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    Large and well-formed crystals of strontium chlorapatite [Sr5Cl(PO4)3] were grown for the first time from a sodium chloride flux. The obtained crystals were colorless and transparent. The crystal growth of Sr5Cl(PO4)3 was conducted by heating a mixture of solute and flux at 1100 °C for 10 h, and then cooling to 500 °C at a rate of 5 °C h−1. Hexagonal prismatic crystals with lengths of up to 8.6 mm and widths of 2.1 mm were grown from high-temperature solutions containing 0.05–0.9 mol% solute. The most suitable solute content for the growth of prismatic crystals was 0.2 mol%. The prismatic crystals were bounded by the {101-0} and {101-1} faces. The aspect ratios were in the region of 1.1 to 4.2. Hexagonal needle crystals with lengths of up to 2.6 mm and widths of 60 µm were obtained during every growth run. The needle crystals were elongated in the <0001> directions, with aspect ratios ranging from 33 to 66. The major constituents were almost homogeneously distributed in the prismatic and needle crystals. The solubility of Sr5Cl(PO4)3 crystals in NaCl flux increased with increasing temperature, reaching about 0.25 mol% solubility at 1100 °C.
  • Naohiro Kameta, Hisanori Imura
    Type: Article
    Subject area: AI
    2001 Volume 74 Issue 9 Pages 1641-1647
    Published: 2001
    Released: November 01, 2002
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    Enhancement of the extraction of lanthanoid(III) (Ln) with 2-thenoyltrifluoroacetone (Htta) in cyclohexane or benzene has been observed by the addition of tris(acetylacetonato)chromium(III) (Cr(acac)3). The equilibrium analysis suggested that the effect of Cr(acac)3 could be ascribed to the formation of a 1 : 1 adduct of Ln(tta)3 with Cr(acac)3, i.e., a binuclear complex, in the organic phase. The formation constants (βs,1) of the adducts were determined across the Ln series. The βs,1 values decreased with decrease in the ionic radii of Ln in the light Ln, and were constant in the heavy Ln. Spectroscopic studies such as electronic absorption, IR, and 1H NMR were performed to explain the difference between the light and heavy Ln. The adduct of light Ln is mainly an inner sphere complex in which Cr(acac)3 displaces the coordinated water of the Ln chelate and directly coordinates to the Ln ion. On the other hand, the adduct of heavy Ln is an outer sphere complex formed by the hydrogen bonding between Cr(acac)3 and the coordinated water of the Ln chelate. Abilities of Cr(acac)3 as a complex ligand, i.e., the basicity and the steric factor, were evaluated by comparing with Co(acac)3 reported previously.
  • Hari Mohan, Jai Pal Mittal
    Type: Article
    Subject area: OB
    2001 Volume 74 Issue 9 Pages 1649-1659
    Published: 2001
    Released: November 01, 2002
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    Pulse radiolysis technique has been employed to investigate the nature and the redox properties of the transient species generated on radiolysis of aqueous solution of (4-methylthiophenyl)methanol (MTPM). Pulse radiolysis in 1,2-dichloroethane, reaction with specific one-electron oxidants (Cl2•−, SO4•−, Tl2+, Br) and reaction of OH radicals in acidic solution showed absorption bands at 320 and 545 nm; these are assigned to solute radical cation with positive charge on the benzene ring. OH-adduct was observed in neutral solution. The oxidation potential for MTPM/MTPM•+ couple is determined to be 1.55 ± 0.04 V vs NHE. eaq reacts with a bimolecular rate constant of 1.5 × 109 dm3 mol−1 s−1 and the transient absorption bands (λmax = 320, 470 nm) are assigned to the solute radical anion. E0 value for MTPM/MTPM•− couple is determined to be −1.84 ± 0.04 V vs NHE. The redox properties of the transient species formed on reaction with OH, H, and O•− have been evaluated.
  • Takanori Wakabayashi, Masao Shiozaki, Saori Kanai, Shin-ichi Kurakata
    Type: Article
    Subject area: OB
    2001 Volume 74 Issue 9 Pages 1661-1665
    Published: 2001
    Released: November 01, 2002
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    D-Glucosaminylacetic acid derivatives (10, 11 and 12) of GLA-60 were synthesized to investigate the LPS-antagonistic activity toward human monoblastic U937 cells. Compounds 10 and 11 show weak LPS-antagonistic activity, but 12 shows both LPS-antagonistic and -agonistic activities, depending on the concentration.
  • Hyun-Joon Ha, Young-Gil Ahn, Jun-Sik Woo, Gwan Sun Lee, Won Koo Lee
    Type: Article
    Subject area: OB
    2001 Volume 74 Issue 9 Pages 1667-1672
    Published: 2001
    Released: November 01, 2002
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    Asymmetric synthesis of β-amino-α-hydroxy acids, key components of medicinally important molecules including Paclitaxel, KRI-1314, amastatin, and microginin, has been attained from the aldimine coupling of chiral imines N-alkylidene-(S)- or (R)-α-methylbenzylamine with (Z)-α-methoxyketene methyltrimethylsilyl acetal, followed by demethylation, hydrogenolysis, and hydrolysis.
  • Takabumi Nagai, Kazuhisa Fujii, Ikuko Takahashi, Miwa Shimada
    Type: Article
    Subject area: OB
    2001 Volume 74 Issue 9 Pages 1673-1678
    Published: 2001
    Released: November 01, 2002
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    Trifluoromethyl (CF3)-substituted donor–acceptor norbornadiene (NBD) derivatives were synthesized. The photoisomerization of CF3-NBD derivatives proceeded smoothly. The thermal stability of quadricyclane (QC) derivatives obtained from CF3-NBD derivatives was examined, and it was found that the CF3 group increased the thermal stability of the QC derivatives. Furthermore, CF3-NBD derivatives exhibited efficient fatigue resistance.
  • Motoko Hirooka, Yoko Mori, Akiko Sasaki, Shinkiti Koto, Yoshika Shinod ...
    Type: Article
    Subject area: OB
    2001 Volume 74 Issue 9 Pages 1679-1694
    Published: 2001
    Released: November 01, 2002
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    β-D-Ribofuranosyl-(1→3)-α-L-rhamnopyranosyl-(1→3)-L-rhamnopyranose, the trisaccharide repeating unit of the C. freundii O28,1c O-specific polysaccharide, was synthesized using in situ activating glycosylation of the 1-OH sugar derivatives and a reagent mixture of trimethylsilyl bromide, cobalt(II) bromide, tetrabutylammonium bromide, and molecular sieves 4A. Regioselective tritylation was useful for synthesizing the 3-OH derivatives of methyl, allyl, and benzyl α-L-rhamnosides.
  • Teruyuki Komatsu, Tomoyuki Okada, Miho Moritake, Eishun Tsuchida
    Type: Article
    Subject area: OB
    2001 Volume 74 Issue 9 Pages 1695-1702
    Published: 2001
    Released: November 01, 2002
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    Double-sided porphinatoiron(II)s with polar substituents [R; hydroxy (FeDP(OH)), methoxy (FeDP(OMe)), and acetoxy (FeDP(OAc))] on the 2,2-dimethylpropanoyloxy-fence groups have been synthesized. FeDP(OMe) and FeDP(OAc) formed five-N-coordinated high-spin Fe2+ complexes with an intramolecularly bound axial imidazole in toluene (or CH2Cl2) under an N2 atmosphere. Upon the addition of O2, they produced stable O2 adducts at 25 °C; their half-lives in water-saturated toluene (50–77 h) are 2–3 fold longer compared to that of the single-face encumbered porphinatoiron(II) (FeP). Their O2-binding parameters are almost identical to that of FeDP(H), which has nonpolar substituents on the fences. In contrast, FeDP(OH) showed a significantly low O2-binding affinity and was immediately oxidized to the Fe3+ state after contact with bubbling O2 gas. The incorporation of these FeDPs into the human serum albumin (HSA) provided artificial hemoproteins, which can reversibly bind and release O2 under physiological conditions (in aqueous media, pH 7.3, 37 °C) like hemoglobin and myoglobin. The half-life of the dioxygenated HSA–FeDP(H) reached 5 h (37 °C). This corresponded to a 2.5-fold increase compared to that of HSA–FeP. The time dependences of the absorption changes accompanying the O2- and CO-rebindings to the HSA–FeDPs after laser flash photolysis were composed of two phases. These observations indicate that the recombination of O2 and CO to the central Fe2+ ion is affected by the microenvironments around the FeDPs in the HSA structure, e.g. a steric hindrance of the amino acid residue and a difference in polarity. Furthermore, FeDP(H) incorporated into HSA showed a high stability against H2O2.
  • Teruyuki Komatsu, Shoichi Hayakawa, Tetsuya Yanagimoto, Makiko Kobayak ...
    Type: Article
    Subject area: OB
    2001 Volume 74 Issue 9 Pages 1703-1707
    Published: 2001
    Released: November 01, 2002
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    The iron complex of tetrakis[2,6-di(alkanoyloxy)phenyl]porphyrin derivative with seven phosphocholine head groups and an N-alkylimidazole side-chain as the proximal base (octopus-porphyrin) has been synthesized. The ferrous complex (7b) was easily dispersed in water to provide a stable colloid. Transmission electron microscopy and scanning force microscopy of the evaporated solution showed spherical micelles with a diameter of 8 nm, which probably consists of a dimer of 7b. These micellar aggregates could reversibly coordinate O2 at 25 °C; and the O2-binding parameters are also given.
  • Kazuhiro Takenaka, Yasushi Obora, Li Hong Jiang, Yasushi Tsuji
    Type: Article
    Subject area: OB
    2001 Volume 74 Issue 9 Pages 1709-1715
    Published: 2001
    Released: November 01, 2002
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    X-ray crystallographic analysis and CPMAS solid-state NMR measurements of tetrakis(diphenylphosphino)calix[4]arene tetramethyl ether (1) elucidated that in the solid-state 1 adopts a flattened partial cone conformation having C1 symmetry. In solution, on the other hand, the 1H, 13C, and 31P NMR spectra measured at −20 °C indicated that 1 has a partial cone conformation with a mirror plane. Two-dimensional 31P EXSY and variable-temperature 31P NMR spectra reveal a fluxional behavior of 1 in solution on the NMR time scale due to annulus rotation from the methoxy side. Concerning the energetics for the four conformers of 1, an ab initio molecular orbital calculation showed that the partial cone conformation is the most stable form, while the cone and the 1,3-alternate conformers are only slightly less stable.
  • Hongqi Li, Keiji Nishiwaki, Kenichiro Itami, Jun-ichi Yoshida
    Type: Article
    Subject area: OB
    2001 Volume 74 Issue 9 Pages 1717-1725
    Published: 2001
    Released: November 01, 2002
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    Molecular orbital calculations revealed that the introduction of a silyl group onto the 2-position of 1,3-dithiole caused significant decrease of the ionization potential and that 2-silyl-1,3-dithioles served as a pseudo π-electron system. The silyl group could also be utilized as a bridge for linking π-electron systems to achieve artificial stacking. These concepts led us to the design and synthesis of silyl-substituted 1,3-benzodithioles as candidates for new electron donors. The oxidation potential of monosilyl-substituted 1,3-benzodithiole was found to be significantly less positive than that of the parent 1,3-benzodithiole. The introduction of the second silyl group caused further decrease of the oxidation potential. Compounds composed of two 1,3-benzodithiole units linked by a silyl group were also synthesized. These showed comparable oxidation potentials to those of the corresponding monomeric compounds. The effect of stannyl-substitution onto the 2-position of 1,3-dithiole was found to be larger than that of silyl-substitution. The effects of silyl- and stannyl-substitution for related systems such as thioanisole and 1,3-dithiane were also studied.
  • Yuko Nishinaka, Tetsuya Satoh, Masahiro Miura, Hideaki Morisaka, Masak ...
    Type: Article
    Subject area: OB
    2001 Volume 74 Issue 9 Pages 1727-1735
    Published: 2001
    Released: November 01, 2002
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    1-Naphthols efficiently couple with internal alkynes via cleavage of the C–H bond at the peri-position in the presence of a catalyst system of [IrCl(cod)]2/PBut3 to selectively afford the corresponding 8-vinyl-1-naphthol derivatives. N-(1-Naphthyl)benzenesulfonamides can similarly react with the alkynes. The reaction of salicylaldehyde with the alkynes using the catalyst system gives 2-hydroxyphenyl vinyl ketones via cleavage of the aldehyde C–H bond.
  • Masa-aki Sato, Mune-aki Sakamoto, Shin-ichiro Kashiwagi, Tomohiro Suzu ...
    Type: Article
    Subject area: OB
    2001 Volume 74 Issue 9 Pages 1737-1742
    Published: 2001
    Released: November 01, 2002
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    A ferrocenyl end-substituted terthiophenes derivative and a sexithiophene derivative were prepared as model compounds for a molecular wire. Electrochemical measurements and absorption spectroscopy were performed to elucidate the oxidation process and the oxidized states of those model compounds. The first oxidation of the model compounds took place in the ferrocene moieties (terminals). The resultant oxidized species in the ferrocene moieties seeped into the oligothiophene moieties (wires) and spread over two or three thiophene rings. Further oxidation of the ferrocenyl-terthiophene derivative did not occur, whereas that of the ferrocenyl-sexithiophene derivative produced an oxidized species, such as a cation radical in the sexithiophene moiety.
  • Tateaki Wakamiya, Akinori Yamamoto, Keita Kawaguchi, Tomohiko Kinoshit ...
    Type: Article
    Subject area: OB
    2001 Volume 74 Issue 9 Pages 1743-1749
    Published: 2001
    Released: November 01, 2002
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    A novel spider toxin, NPTX-594, comprised of four constituents: i.e., 2,4-dihydroxyphenylacetic acid (Dhpa), asparagine, 4,8-diaza-1,12-dodecanediamine (Dada), and lysine, was chemically synthesized. The synthetic compound was completely identical with the natural product as regards 1H NMR and mass spectra. The structure of NPTX-594 was thus determined synthetically to be N12-(Dhpa-Asn)-N1-Lys-Dada, as proposed by spectrometric elucidation.
  • Tadatomo Kawai, Shinya Teramachi, Takamitsu Yokoyama
    Type: Article
    Subject area: AM
    2001 Volume 74 Issue 9 Pages 1751-1755
    Published: 2001
    Released: November 01, 2002
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    The chemical composition distributions (CCDs) of biosynthesized poly(3-hydroxybutyrate-co-3-hydroxyvalerate), P(3HB-co-3HV), samples with different average compositions were determined by temperature rising elution fractionation (TREF). P(3HB-co-3HV) samples were supplied by Sigma–Aldrich Co. Inc. According to catalog data, the 3HV contents were about 8, 14, and 24 mol%, respectively. The TREF condition was as follows: the sample concentration was 0.3% dissolved in acetonitrile at 75 °C; the column temperature was slowly (2 °C/h) decreased from 75 °C to 0 °C to crystallize the sample. The fractions were eluted with acetonitrile by stepwise increasing the temperature by 5 °C.
    The chemical compositions of the original samples and the fractions were determined by 1H NMR. Cumulative CCD curves were constructed from the fractionation data for the respective samples. It became clear that these samples had bimodal CCDs with two discrete peaks, that is, one part in the wide composition range around 10–15 mol% of 3HV contents and another part at different compositions.
  • Tiesheng Li, Masaya Mitsuishi, Tokuji Miyashita
    Type: Article
    Subject area: AM
    2001 Volume 74 Issue 9 Pages 1757-1760
    Published: 2001
    Released: November 01, 2002
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    We describe the lithographic properties of poly(N-isopentylmethacrylamide-co-t-butyl 4-vinylphenyl carbonate) [p(iPMA-tBVPC)] which has a structure that is subject to the main chain scission and to deprotection of t-butoxycarbonyloxy group by deep UV irradiation. The positive-tone patterns of the p(iPMA-tBVPC) LB film with 60 layers could be obtained by deep UV light irradiation, followed by development with alkaline aqueous solution. The resolution of the pattern was 0.75 μm, which is the resolution limit of the photomask employed. The photopattern formation with the copolymer [p(iPMA-tBVPC)] LB film was more sensitive than the homopolymer poly(N-isopentylmethacrylamide) [p(iPMA)] LB film. The etching resistance of the p(iPMA-tBVPC) LB film deposited for the pattern of the gold film is also investigated.
  • Osamu Yamamoto, Jun Sawai
    Type: Article
    Subject area: AM
    2001 Volume 74 Issue 9 Pages 1761-1765
    Published: 2001
    Released: November 01, 2002
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    After ion-exchange resins were treated for 24 h by an aqueous solution of [Zn(NH3)4]2+ complex, the treated resins were carbonized for 10 min in nitrogen gas at each temperature. The activated carbons with ZnO were then prepared. The antibacterial activity on their carbon samples was studied without the presence of light. ZnO of hexagonal type was detected in the carbon samples, of which the amount decreased with an increase in the carbonization temperature. However, the specific surface areas of carbon samples increased with increasing the carbonization temperature of the resin. The antibacterial activity on carbon samples containing ZnO increased with a decrease of the carbonization temperature and an increase of the amount of ZnO in the samples. From a comparison of the antibacterial activity between Staphylococcus aureus and Escherichia coli, it was found that the activity for Staphylococcus aureus was stronger than that for Escherichia coli. The concentration of hydrogen peroxide increased linearly with an increase in the amount of carbon samples. The occurrence of antibacterial activity was found to be due to the generation of hydrogen peroxide from ZnO in activated carbons.
  • Jun Li, Shinsaku Shiraishi, Kazuaki Kudo
    Type: Article
    Subject area: AM
    2001 Volume 74 Issue 9 Pages 1767-1773
    Published: 2001
    Released: November 01, 2002
    JOURNALS RESTRICTED ACCESS
    A structurally ordered polyimide with the main chain having the complete “head-to-tail” bonding sequence (HTPI) or the complete “head-to-head” bonding sequence (HHPI) was prepared. The synthesis was based on the unique reactivity of an unsymmetric spiroalicyclic tetracarboxylic dianhydride, rel-(1R,5S,6R)-spiro[3-oxabicyclo[3.2.1]octane-6,3′-tetrahydrofuran]-2,2′,4,5′-tetrone (DAn), which has one 5-membered and one 6-membered anhydride. Equimolar amount of amine reacts with this compound predominantly at the 6-membered ring. Thus, the reaction of DAn with 1 molar amount of 4-nitroaniline and the subsequent methanolysis and reduction gives a monomer for a head-to-tail polyimide, which was successfully converted to HTPI through a polycondensation-dehydration sequence. Additionally, a new dianhydride monomer MHH, which is a 2 : 1 adduct of DAn and p-phenylenediamine (PPD), was prepared. MHH was subjected to polycondensation with 1 molar amount of PPD and the condensate was dehydrated to give HHPI. Slow addition of PPD into the solution of DAn also afforded a semi head-to-head polyimide. The polyimides had inherent viscosity in the range of 0.20–0.73 dL/g and were characterized by NMR and IR spectra through a comparison with those of their random isomer RPI. No obvious differences in properties, such as solubility and thermal stability, between the ordered polyimides (HTPI and HHPI) and the random counterpart were found in this study.
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