Bulletin of the Chemical Society of Japan
Online ISSN : 1348-0634
Print ISSN : 0009-2673
ISSN-L : 0009-2673
Volume 77 , Issue 12
Showing 1-23 articles out of 23 articles from the selected issue
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Theoretical and Physical
  • Shigenobu Hayashi, Yoriko Sonoda
    2004 Volume 77 Issue 12 Pages 2159-2164
    Published: 2004
    Released: December 10, 2004
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    Molecular arrangements in crystalline solids of p,p′-disubstituted (1E,3E,5E)-1,6-diphenyl-1,3,5-hexatrienes (DPHs) have been studied by two-dimensional 1H spin-exchange NMR. The mixing time dependence of the cross peak intensity has been analyzed, and the time constants representing proton spin exchange rates have been estimated. Data for methoxy derivative 1 demonstrate the presence of intermolecular spin exchange between triene protons and methoxy protons; thus one may conclude that a methoxy group is located close to a hexatriene chain of an adjacent molecule. On the other hand, there is no evidence of intermolecular spin exchange for formyl derivative 2.
  • Noriaki Funasaki, Koji Yamauchi, Seiji Ishikawa, Shun Hirota
    2004 Volume 77 Issue 12 Pages 2165-2171
    Published: 2004
    Released: December 10, 2004
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    Proton NMR spectroscopy was applied to determine the macroscopic binding constants and the solution structures of the 1:1 and 1:2 complexes between N,N,N-hexyldimethyloctylammonium bromide (HDOAB) and α-cyclodextrin (α-CD). The terminal methyls of the hexyl and octyl groups of HDOAB are distinguishable from each other in the NMR spectrum. The chemical-shift variations of these methyls, compared with the α-CD complexes of hexyltrimethylammonium (HTAB) and octyltrimetylammonium (OTAB) bromides, indicated that this system formed two 1:1 complexes (10% hexyl-in complex and 90% octyl-in complex). The chemical-shift variations of HDOAB and α-CD protons with the 1:1 and 1:2 complexations were quantitatively explained based on the assumption that the geometry of the hexyl and octyl groups of the HDOAB complexes with α-CD is identical to that of the HTAB and OTAB. This finding indicated that the hexyl and octyl groups bind to α-CD independently. Based on the assumption that the microscopic binding constants of the hexyl and octyl groups of HDOAB are identical to the macroscopic 1:1 binding constants of HTAB and OTAB with α-CD, the mole fraction of the hexyl-in complex in the 1:1 complex was estimated to be 0.11. This is very close to the above-mentioned estimation from the chemical-shift variations of the terminal methyls. The intensities of intermolecular cross-peaks on the ROESY spectrum of a 3 mM HDOAB and 3 mM α-CD solution indicated that the octyl-in complex is the predominant 1:1 complex. The present method and result will serve to estimate noncovalent interactions, binding equilibria, and solution structures of other multiple supramolecular complexes.
  • Yoshinori Hirata, Osamu Kawashima
    2004 Volume 77 Issue 12 Pages 2173-2178
    Published: 2004
    Released: December 10, 2004
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    By using transient absorption and photoconductivity measurement techniques, we have investigated the photoionization process of N,N-diethyl-p-phenylenediamine in various polar solvents. Significant excitation wavelength and excitation intensity effects were observed in alcoholic solvents. The slowly rising component of the photoconductivity in hundreds of nanoseconds or longer time scale is ascribed to the dissociation of the monophotonically produced ion pairs. In addition, a photoconductivity signal that has almost the same duration as the excitation laser pulse and is due to the geminate pair formed via the two-photon ionization is clearly observed with the 248-nm excitation. On the other hand, the biphotonic process was negligible with the 351-nm excitation in ethanol and 1-propanol. The monophotonically formed long-lived ion pair did not contribute to the conductivity. The long lifetime of the ion pair indicates that not only the Coulombic interaction but also the exciplex-like specific interaction is important.
  • Jun-ichi Aihara
    2004 Volume 77 Issue 12 Pages 2179-2183
    Published: 2004
    Released: December 10, 2004
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    The conventional interpretation of bond-length equalization gives a misleading picture of the aromaticity on charged π-systems. A charged π-system in general is reluctant to undergo marked bond-length alternation, even if it is antiaromatic with a negative topological resonance energy. The pentalene dication and the C60 decacation are antiaromatic with a modest distortion of the molecular skeleton. Small maximum eigenvalues of the bond–bond polarizability matrices support the absence of second-order double-bond fixation in many charged antiaromatic π-systems.
  • Jun-ichi Nakamura, Shinji Suzuki, Kohshin Takahashi, Chiho Yokoe, Kazu ...
    2004 Volume 77 Issue 12 Pages 2185-2188
    Published: 2004
    Released: December 10, 2004
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    The energy conversion efficiency of a two-layer organic solar cell consisting of a perylene pigment (PV) and regioregular polythiophene polymer (P3DT) was 0.99% under illumination with simulated solar light (AM 1.5–100 mW cm−2). The photovoltaic mechanism is discussed on the basis of the ionization potential of the component materials. The photoinduced hole-transfer from PV to P3DT quickly occurred at the PV/P3DT interface because of the large free energy change of 1.2 eV, then the subsequent charge separation efficiently proceeded, resulting in a large short-circuit photocurrent of 6.5 mA cm−2. On the other hand, the open-circuit photovoltage was only 0.42 V because the LUMO level of PV is close to the HOMO level of P3DT. The difference between the LUMO and the HOMO can be attributed to the open-circuit photovoltage.
  • Hiromichi Uehara
    2004 Volume 77 Issue 12 Pages 2189-2191
    Published: 2004
    Released: December 10, 2004
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    A non-Born–Oppenheimer effective Hamiltonian for diatomic molecules with optimal fitting parameters, i.e., determinable clusters of expansion coefficients of Born–Oppenheimer corrections, has been derived. The effective Hamiltonian has formally the same form as Dunham’s Hamiltonian, except for additional corrections for successive ξ′i terms of a series expansion of the rotational parameter B(ξ′), extending the determinacy of the optimal parameters, ΔBa,b, Δωa,b, Δaiqa,b, riqa,b, in general for i = 1, 2, 3, ..., if spectra of isotopomers of atoms A and B are analyzed simultaneously. The effective Hamiltonian provides a clear-cut understanding of determinable correction parameters; e.g., in Dunham-type potential fits to spectral transitions for the single isotopomer optimal parameters δriq (i = 1, 2, ...) for corrections of series expansion terms of B(ξ′) should explicitly be included. The physical significance of the optimal parameters as well as of conventional molecular parameters, Be, −De, He, ωe, and −αe, etc., is described.
  • Takanori Fukahori, Sadakatsu Nishikawa, Kyohei Yamaguchi
    2004 Volume 77 Issue 12 Pages 2193-2198
    Published: 2004
    Released: December 10, 2004
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    Ultrasonic absorption method was applied to elucidate the dynamic properties of host–guest complexation between α-cyclodextrin or β-cyclodextrin (host) and butanol isomers (guest) at 25 °C. The aim of this work was to reveal the effect of a structural difference in the hydrophobic part of a guest on the kinetic parameters for an inclusion reaction with cyclodextrins. Moreover, it was expected to clarify the effect of the cavity size on the reaction. Only when the host and guest existed together in water, a clear single relaxational phenomenon was observed. The cause of the relaxation was responsible for the complexation reaction between the host and the guest. The rate and equilibrium constants were obtained from the concentration dependence of the relaxation frequency, and the standard volume changes of the complexation reaction were from the maximum absorption per wavelength. The backward rate constant, kb, was very dependent on the structure of the guest molecule. The kb value decreased in the next hydrophobic series, nor- < sec- < tert- in β-CD systems, although a smaller kb value was observed when the guest possessed a normal carbon chain in α-CD systems. The results of the volume change of the reaction implied that α-CD could only include a guest quite shallowly, and almost the entire guest molecule was included into the β-CD cavity.
  • Keizo Horiuchi, Chieko Iijima, Shinji Miyagi, Hayato Yogi, Takanori Fu ...
    2004 Volume 77 Issue 12 Pages 2199-2202
    Published: 2004
    Released: December 10, 2004
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    The 1H NMR spin–lattice relaxation times and the second moments of the resonance linewidth were measured as a function of temperature in (C2H5NH3)2[ZnBr4]. The crystal structure at 295 K was determined to be orthorhombic with space group of P212121 by the single-crystal X-ray diffraction method. The crystal undergoes a 1st order structural phase transition at Tc = 300 K, which is driven by the disordering of cationic orientations. The crystal structure above Tc is inferred to be orthorhombic with space group of Pmnb().
  • Takeo Suga, Yong-Jin Pu, Kenichi Oyaizu, Hiroyuki Nishide
    2004 Volume 77 Issue 12 Pages 2203-2204
    Published: 2004
    Released: December 10, 2004
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    The electron-transfer rate constants of nitroxide derivatives, 4-(N-t-butyl-N-oxylamino)-t-butylbenzene, 4-(N-t-butyl-N-oxylamino)methoxybenzene, and 2,2,6,6-tetramethylpiperidinyl-N-oxyl, were investigated by electrochemical methods, which demonstrated that these radicals can potentially be used as a high power-rate electrode-active material due to their fast electron-transfer process.
Analytical and Inorganic
  • Daisuke Yoshioka, Masahiro Mikuriya, Makoto Handa
    2004 Volume 77 Issue 12 Pages 2205-2211
    Published: 2004
    Released: December 10, 2004
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    Polymeric chain complexes, [Ru2(piv)4(pyz)]n(BF4)n·3nH2O (1), [Ru2(piv)4(4,4′-bpy)]n(BF4)n·nH2O (2), [Ru2(piv)4(dabco)]n(BF4)n·2nH2O (3), [Ru2(piv)4(phz)]n(BF4)n (4), and [Ru2(piv)4(H2O)2(tmpyz)]n(BF4)n·nCH2Cl2 (6), (Hpiv = pivalic acid, pyz = pyrazine, 4,4′-bpy = 4,4′-bipyridine, dabco = 1,4-diazabicyclo[2.2.2]octane, phz = phenazine, and tmpyz = tetramethylpyrazine), were synthesized and characterized by elementary analyses, infrared and electronic spectroscopies, and variable-temperature magnetic susceptibilities (4.5–300 K). A tetranuclear complex, [{Ru2(piv)4(H2O)}2(phz)](BF4)2 (5), was also synthesized, and a “dimer of dimers” structure was confirmed by an X-ray structure analysis. The crystal structure of 6 shows that [Ru2(piv)4(H2O)2]+ units are linked by hydrogen bonds with tmpyz molecules, giving zigzag chains with Ru1–O5···N1 angle of 108.1(2)°. A red-shift of the δ**(Ru2) → σ*(Ru–O), and δ(Ru2) → δ*(Ru2) transition bands of the RuII,III2 core was observed in polymeric chain adducts 14. All of the present complexes show a very weak antiferromagnetic interaction between the dinuclear units with a considerable zero-field splitting parameter.
Organic and Biological
  • Tadashi Endo, Keitaro Sugio, Sadahiro Kogure, Suguru Horikosi, Motohir ...
    2004 Volume 77 Issue 12 Pages 2213-2218
    Published: 2004
    Released: December 10, 2004
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    Oxidation of a pair of associating thiols 1 and 2, each having a binding site [–C(=O)NHC(=O)NH–] and a recognition site (R1 or R2), is examined at various temperatures as a function of mole fraction of water (xw) in aqueous binary solvents with EtOH, CH3CN, and i-PrOH. The selectivity (r) — a measure of the degree of molecular recognition in the oxidation — is represented by the logarithmic ratio of the yield of the unsymmetrical disulfide 4 to twice that of the symmetrical one 3. It is found that three distinct patterns are present in temperature–recognition profiles, depending on composition of the aqueous binary solvents: (1) “progressive decrease” in the lower xw region; (2) “presence of a maximum” in the medium xw region; (3) “progressive increase” in the higher xw region. It is also clarified that aqueous mixed solvents in the medium xw region are indispensable for maximal recognition to occur against temperature (the presence of a maximum in the temperature–selectivity relationship). Dependence of the r on the xw at lower and higher temperatures, presence of three distinct patterns in the temperature–recognition profiles, and so on are discussed in relation to the maximal recognition.
  • Yohsuke Shiraishi, Hiroshi Yamauchi, Takashi Takamura, Hideki Kinoshit ...
    2004 Volume 77 Issue 12 Pages 2219-2229
    Published: 2004
    Released: December 10, 2004
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    The reaction of peptides containing an N-Boc- or N-Z-α-tosylglycine residue at the N-terminus with a variety of excess nitro compounds under basic conditions to give the nitro compound-adducts in good yields, followed by the elimination of nitrous acid from the adducts to afford the corresponding dipeptide containing α,β-didehydroamino acids with (Z)-configuration predominantly. Treatment of the same starting materials with aldehydes in the presence of base and tributylphosphine also gave a dipeptide containing α,β-didehydroamino acids with high (Z)-selectivity in satisfactory yields. The present method can be successfully applied to the synthesis of a protected leucine enkephalin analog.
  • Anuj Sharma, Bhupendra P. Joshi, Arun K. Sinha
    2004 Volume 77 Issue 12 Pages 2231-2235
    Published: 2004
    Released: December 10, 2004
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    Methoxylated (E)-arylalkenes (1a1k) were prepared in two steps by an improved Grignard reaction comprising the reverse addition of alkylmagnesium bromide to benzaldehydes (2a2k) in anhydrous ether and toluene into arylalkanols (3a3k) in high yield, followed by dehydration with silica gel under microwave irradiation for 3–12 min, depending upon the substituents attached to the aromatic ring to afford hypolipidemic active α-asarone (1a) and related methoxylated (E)-arylalkenes (1b1k).
  • Kozo Hiwatari, Yoshihito Kayaki, Koshi Okita, Tomohiro Ukai, Isao Shim ...
    2004 Volume 77 Issue 12 Pages 2237-2250
    Published: 2004
    Released: December 10, 2004
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    A new process for converting secondary amines into N,N,N′,N′-tetraalkyloxamides under CO pressure, catalyzed by homogeneous palladium complexes in the presence of 1,4-dichloro-2-butene (DCB) as an oxidant, has been developed. The mechanism of the oxidative double-carbonylation process, consisting of the oxidation of Pd(0) to Pd(II) with DCB through a β-chloride elimination of the η3-(chloromethyl)allylpalladium(II) intermediate, the formation of mono- and bis(carbamoyl)palladium species, and a reductive elimination of the two carbamoyl ligands, is proposed based on studies of the behavior of carbamoylpalladium complexes. When primary amines are employed with DCB as the oxidant, N,N′-dialkyloxamide is catalytically produced, whereas urea is exclusively produced when iodine is used as the oxidant. The reaction of an N-monopropylcarbamoylpalladium complex with propylamine under CO gave N,N′-dipropylurea, whereas a treatment with diethylamine yielded unsymmetrical N,N-diethyl-N′-propylurea, implying the intermediate formation of propyl isocyanate that is converted into the urea upon a reaction with the added amine. A kinetic study on the reaction of chloro-N-propylcarbamoylpalladium with triethylamine suggested a process proceeding through a base-promoted deprotonation of the N-monoalkylcarbamoyl ligand to form propyl isocyanate.
  • Ken Takaki, Jun Yamamoto, Kimihiro Komeyama, Tomonori Kawabata, Katsuo ...
    2004 Volume 77 Issue 12 Pages 2251-2255
    Published: 2004
    Released: December 10, 2004
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    Visible light irradiation of alkanes in acetonitrile with CuCl2 and FeCl3 catalysts under atmospheric dioxygen gave the corresponding alcohols and ketones effectively; in these reactions, the total selectivity of the products did not decrease so much with increase of alkane conversion. For example, cyclohexanol and cyclohexanone were formed with ca. 70% selectivity at 50% conversion, because overoxidation of the products took place more slowly than cyclohexane oxidation. The relative reactivity values of cycloalkanes increased as their ring-sizes decreased. In the oxidation of hexane, the reactivity ratio of C1-/C2-/C3-H was found to be 1.0/1.4/1.8 with CuCl2 and 1.0/4.6/6.6 with FeCl3, respectively. Toluene and diphenylmethane were more reactive than cyclohexane with FeCl3, as expected, whereas the alkane was oxidized faster than the benzylic compounds in the separate reaction with CuCl2. Moreover, the alkane oxidation could be comparably performed by sunlight instead of an artificial lamp.
  • Fuminao Doi, Taiga Ohara, Takahisa Ogamino, Keiko Higashinakasu, Koji ...
    2004 Volume 77 Issue 12 Pages 2257-2263
    Published: 2004
    Released: December 10, 2004
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    Lewis acid-promoted 1,2-shift rearrangement reactions of the spirodienones, generated by the anodic oxidation of phenol derivatives, provided corresponding chromans. In addition to steric repulsion, electron-donating or withdrawing characteristics of the arylic substituents controlled the direction of the rearrangements. The plant growth inhibitory activity of several chroman derivatives was evaluated. In contrast to apparent inhibitions of 21c and 22c against both cress and oat, the selective activity against coleoptile and root of oat was observed in 21a, 21b, and 22d. Interestingly, the regioisomer 22b of 21b showed no activity.
  • Mazaahir Kidwai, Ruby Thakur, Richa Mohan
    2004 Volume 77 Issue 12 Pages 2265-2267
    Published: 2004
    Released: December 10, 2004
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    The Lewis acid (borontrifluoride etherate) catalyzed novel synthesis of 2,4,6-trisubstituted-6H-1,3-oxazines is described here. Also, a new route towards an environmentally benign synthesis of the title compounds has been developed using montmorillonite K-10 clay as a catalyst under microwave irradiation (MWI). The procedure replaces the Lewis acid, and the products are obtained in a high yield and shorter reaction time.
  • Kei Shimoda, Naoji Kubota, Hiroki Hamada, Shin-ya Yamane, Toshifumi Hi ...
    2004 Volume 77 Issue 12 Pages 2269-2272
    Published: 2004
    Released: December 10, 2004
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    Asymmetric transformation of enones was investigated with cultured cells of Synechococcus sp. PCC 7942 (a cyanobacterium). The cells reduced both the endocyclic C–C double bond of s-trans enones and the exocyclic C–C double bond of s-cis enones with high enantioselectivity to afford optically active α-substituted (S)-ketones under illumination. In addition, the reduction of the double bond of these enones was accompanied by the formation of saturated alcohols. The cells preferentially reduced simple aliphatic ketones rather than cyclic ones to the corresponding (S)-alcohols with excellent enantioselectivity.
  • Chiharu Agawa, Keiko Otsuka, Mao Minoura, Yasuhiro Mazaki, Gaku Yamamo ...
    2004 Volume 77 Issue 12 Pages 2273-2281
    Published: 2004
    Released: December 10, 2004
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    During the course of attempts at synthesis of N-phenyl-N-9-triptycylhydroxylamine (1), we found that the reaction of N-9-triptycylhydroxylamine (5) with benzenediazonium-2-carboxylate afforded 3-(2-carboxyphenyl)-1-(9-triptycyl)triazene 1-oxide (6), the structure of which was confirmed by X-ray crystallography. Oxidation of N-(9-triptycyl)aniline (4) with mCPBA gave phenyl 9-triptycyl nitroxide (7) and N-(9-triptycyl)-1,4-benzoquinonimine (8) in small yields. Reduction of 7 with phenylhydrazine gave 1, and O-ethylation of 1 gave O-ethyl-N-phenyl-N-9-triptycylhydroxylamine (2). Results of X-ray crystallography for compounds 2, 4, 7, and 8 and results of dynamic NMR studies for 1, 2, and 8 are presented. In compound 8, Tp–N rotation and C=N topomerization took place on the NMR timescale at high temperatures above 60 °C, and the energy barriers to both processes were obtained. In compounds 1 and 2, dynamic NMR behavior was observed at very low temperatures below ca. −50 °C, and the energy barriers to the respective processes could not be determined except for those related to “Ph-passing”.
Applied and Materials
  • Shujiro Sakaki, Mamoru Tsuchida, Yasuhiko Iwasaki, Kazuhiko Ishihara
    2004 Volume 77 Issue 12 Pages 2283-2288
    Published: 2004
    Released: December 10, 2004
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    The purpose of this work was the preparation of a water-soluble DNA complex with a biocompatible phospholipid polymer for delivering DNA into a target cell. The phospholipid polymer, poly[2-methacryloyloxyethyl phosphorylcholine (MPC)-co-2-aminoethyl methacrylate (AEMA)] (poly(MPC-co-AEMA)), was synthesized and the functions of poly(MPC-co-AEMA) as a DNA carrier were compared with those of a conventional cationic DNA carrier such as poly(L-lysine). We investigated the toxicity of these polymers and the water solubility, structures, and nuclease resistance of the associated DNA/polymer complexes. An evaluation of toxicity in a colony forming test using Chinese hamster fibroblast cells (V-79 cells) indicated that the toxicity of poly(MPC-co-AEMA) is about 40% of that of poly(L-lysine). In the case of a salmon sperm DNA/poly(L-lysine) complex, a water-insoluble precipitate formed. In contrast, the DNA/poly(MPC-co-AEMA) complex was completely water-soluble. Although the DNA/poly(L-lysine) complex did not provide a CD spectrum, the DNA/poly(MPC-co-AEMA) complex did. DNase I hardly degraded the DNA in the DNA/poly(MPC-co-AEMA) complex. To demonstrate the transient expression of β-galactosidase, a plasmid DNA/poly(MPC-co-AEMA) complex was incubated with V-79 cells with chloroquine treatment. Under a phase-contrast microscope after 5-bromo-4-chloro-3-indolyl-β-D-galactopyranoside (X-gal) staining, more stained cells due to the transient expression of β-galactosidase were observed in a sample with the poly(MPC-co-AEMA) complex than in a sample with the poly(L-lysine) complex. From these results came the following conclusions: poly(MPC-co-AEMA) is a useful water-soluble polymer that can form a complex with DNA, and DNA/poly(MPC-co-AEMA) has good potential for DNA delivery into cells.
  • Jianlu Zhang, Xiaoli Wang, Jingwei Hu, Baolian Yi, Huamin Zhang
    2004 Volume 77 Issue 12 Pages 2289-2290
    Published: 2004
    Released: December 10, 2004
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    A novel PEMFC catalytic layer was fabricated by a Nafion-pyrolyzed method, which demonstrated a high performance with a maximum power density of 0.82 W/cm2 on an electrode prepared by this method. The effects of the heat-treatment temperature and Nafion content in the catalyst layer on performance were studied.
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