Bulletin of the Chemical Society of Japan
Online ISSN : 1348-0634
Print ISSN : 0009-2673
ISSN-L : 0009-2673
Volume 79 , Issue 6
Showing 1-21 articles out of 21 articles from the selected issue
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  • Shohei Tashiro, Makoto Fujita
    2006 Volume 79 Issue 6 Pages 833-837
    Published: 2006
    Released: June 06, 2006
    JOURNALS FREE ACCESS
    A coordination host recognized various aromatic peptides containing Trp and Tyr residues in a highly sequence-selective fashion. For example, two similar hexa-peptides, Ac-Ser-Gly-Ala-Trp-Trp-Ala-NH2 and Ac-Ala-Trp-Trp-Ala-Gly-Ser-NH2, were selectively discriminated by the restricted inner space of coordination cages. We also demonstrated that the charged peptides were efficiently discriminated by the cage owing to the highly cationic property of the cage (12+). Furthermore, the cages selectively discriminated two similar peptides, Ac-Ala-Trp-Trp-NH2 and Ac-Ala-Tyr-Tyr-NH2, because of differences in the strength of charge-transfer interaction between the cage and the electron-rich aromatic residues. This selectivity was controlled by modulating the solution pH. The colorization of the aromatic peptide solutions by charge-transfer interaction could also be applicable to the naked-eye recognition of three aromatic residues, Trp, Tyr, and Phe.
Articles
  • Mohamed K. Awad, Shakir T. Abdel-Halim
    2006 Volume 79 Issue 6 Pages 838-844
    Published: 2006
    Released: June 06, 2006
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    Semiempirical molecular orbital calculations have been performed to study the mechanism by which water molecules attack the highly negative oxycyclic oxygen atom of Brooker’s merocyanine 1-methyl-4-(4′-oxidostyryl)pyridinium betaine, M, to form mono-, di-, and tri-hydrated merocyanine complexes. In the case of mono- and di-hydrated complexes, one or two water molecules attack the oxygen atom, respectively, but in the case of the tri-hydrated complex, only two water molecules attack the oxygen atom of M with sp2 hybridization, while the third one forms a H-bond with either one of the oxygen atoms of the coordinated water molecules. The effect of H-bond formation on the molecular and electronic structures of merocyanine is investigated using the atom superposition and electron delocalization molecular orbital (ASED-MO) theory. The calculations show that the hydrated complexes are shifted towards the benzenoid valence structures in the ground state, but shifted towards quinonoid ones upon excitation. On the basis of the calculated charge distribution over the whole skeleton of the complexes, it is found that the dipole moments of the complexes are slightly affected by H-bond formation in the ground state, but strongly decrease upon excitation. The formation of hydrated merocyanine complexes are highly exothermic, downhill reactions, which is explained with respect to the stabilization of the HOMO and oxygen lone-pair levels. We believe that the attacking by water with acidic character on the basic site oxygen atom of merocyanine is a kind of acid–base interaction.
  • Mohamed El-Hefnawy, Kaori Sameshima, Toshio Matsushita, Reiji Tanaka
    2006 Volume 79 Issue 6 Pages 845-856
    Published: 2006
    Released: June 06, 2006
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    The apparent dipole moments (μ) of 2-methoxyethanol (C1E1), 2-ethoxyethanol (C2E1), 2-(2-methoxyethoxy)ethanol (C1E2), and 2-(2-ethoxyethoxy)ethanol (C2E2) were determined in heptane solutions for the mole fraction range of 0 < x < 0.03 at T = 298.15 K. To calculate μ values the molar volumes for these solutions and the refractive indices of the pure components were determined at T = 298.15 K. FT-IR spectra for these solutions were also measured at T = 298 K. The conformations of these compounds and that of the dimer of C1E1 were predicted by ab initio calculations. In order to compare the calculated results with experimental, a statistical calculation was performed. The calculated conformers of the isolated molecules correlated well with the experimental results of the dipole moment and the IR spectra.
  • Ling Jiang, Qiang Xu
    2006 Volume 79 Issue 6 Pages 857-863
    Published: 2006
    Released: June 06, 2006
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    Laser-ablated Sn atoms have been co-deposited with CO molecules in solid argon to produce tin carbonyls. In addition to the previously reported Sn(CO)n (n = 1 and 2) molecules, small tin cluster carbonyls SnnCO (n = 2–5) and Sn2(CO)2 are formed on sample annealing, and are characterized using infrared spectroscopy on the basis of the results of the isotopic substitution, the CO concentration change, and the comparison with theoretical predictions. It is found that Sn2CO, Sn3CO, and Sn5CO are bridge-bonded carbonyl compounds, whereas Sn2(CO)2 and Sn4CO are terminal-bonded carbonyl molecules. The Sn2(CO)2 species observably undergoes photo-induced decomposition to Sn(CO)2. Another interesting finding is that the absorption of Sn4CO shifts from 1994.0 to 1989.8 cm−1 by UV light irradiation, probably due to the change of the electronic state or the matrix effect. The density functional theory calculations have been performed on these molecules and the corresponding small naked tin clusters. Furthermore, energetic analysis for the possible reactions of lead atoms with CO molecules is also given.
  • Takamoto Kawaguchi, Hiroshi Ohki, Koji Yamada, Tsutomu Okuda
    2006 Volume 79 Issue 6 Pages 864-866
    Published: 2006
    Released: June 06, 2006
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    The dynamics of interlayer H2O in VOPO4·2H2O have been studied by 1H and 2H NMR measurements. This compound contains two different kinds of water molecules. One of the two water molecules has a coordination bond to the V in the layer. The 2H NMR spectrum at 150 K was reproduced by one component with the quadrupole-coupling constant QCC = 220 kHz and the asymmetry parameter η = 0.12. This result suggests that all H2O molecules are static at this temperature. In the temperature range of 160–240 K, both interlayer H2O molecules show 180°-flipping motion from the 2H NMR spectra. This motion of the two different H2O molecules suggests the hydrogen-bonding network between these interlayer H2O. The activation energies of this motion could be determined to be 30 kJ mol−1 from the 2H NMR spectrum simulation. Additionally, the diffusional component also appeared above 240 K. Above 270 K, two-dimensional diffusion of the interlayer species is suggested in this material.
  • Havva Demirelli, Mehmet Tümer, Aysegül Gölcü
    2006 Volume 79 Issue 6 Pages 867-875
    Published: 2006
    Released: June 06, 2006
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    In this study, we synthesized the amine compounds 2-{(E)-[(2-aminoethyl)imino]methyl}phenol (H3A) and 2-{(E)-[(3-aminopropyl)imino]methyl}-6-methoxyphenol (H3B) as the starting materials. From reactions of the starting materials with 2-hydroxy-5-methylisophthalaldehyde, phthalaldehyde, and 2-hydroxy-5-t-butylisophthalaldehyde, we prepared the new ligands H3L1–H3L3 and H2L. The Cu(II) and Cd(II) complexes of the ligands have been obtained. Microanalytical data, magnetic moment, 1H(13C) NMR, mass spectra, FT-IR, and conductivity measurements have been used to explain the structures of the ligands and their complexes. The protonation constants of the ligands H3L1–H3L3 have been studied in a 1:1 molar ratio (M:L). Protonation and stability constants of the Schiff bases and their Cu(II) and Cd(II) complexes have been determined by the potentiometric titration method in 50% dioxane–water media at 25.00 ± 0.02 °C under a nitrogen atmosphere and ionic strength of 0.1 M NaClO4. The ligands H3L1–H3L3 have seven protonation constants. In other words, the ligand H2L has six protonation constants. The variation of protonation constants of these compounds were interpreted on the basis of structural effects exposed by the substituents.
  • Kei Onozaki, Kazuo Miyamura
    2006 Volume 79 Issue 6 Pages 876-880
    Published: 2006
    Released: June 06, 2006
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    The reaction between (Bu4N)2[Ni(dmit)2] (Bu4N = tetrabutylammonium, dmit = 2-thioxo-1,3-dithiole-4,5-dithiolato) and the bromide of 1-propyl-1,4-diazabicyclo[2.2.2]octanium (C3DABCO) yielded crystals of the double salt (Bu4N)4(C3DABCO)2[Ni(dmit)2]3 together with (C3DABCO)2[Ni(dmit)2]. The structures of the two crystals have been solved and compared. The crystal of the double salt was made up of one (C3DABCO)2[Ni(dmit)2] and two (Bu4N)2[Ni(dmit)2] units. In both units, planar [Ni(dmit)2]2− was sandwiched by two cations. The Ni–N+ distance of the (C3DABCO)2[Ni(dmit)2] unit in a single salt was 0.3 Å longer than that in the double salt. The ethyl- and butyl-substituted analogues, abbreviated as C2DABCO and C4DABCO, respectively, were also synthesized by a similar procedure, but did not form a double salt. However, the volume of the C4DABCO single salt was found to be smaller than that of the C3DABCO single salt, although the alkyl chain was elongated.
  • Noboru Sekine, Takuya Shiga, Masaaki Ohba, Hisashi Okawa
    2006 Volume 79 Issue 6 Pages 881-885
    Published: 2006
    Released: June 06, 2006
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    A dinucleating compartmental ligand derived from the cyclic [2:1:1] condensation of 2,6-diformyl-4-methylphenol, 1,3-propanediamine, and diethylenetriamine (dien) assumes two isomeric forms in the dinuclear copper(II) complexes, [Cu2(La)](ClO4)2·2H2O (1) and [Cu2(Lb)(AcO)]BPh4 (2). Complex 1 has the ligand in the usual condensation with a trimethylene chain (–(CH2)3–) and a 3-azapentamethylene chain (–(CH2)2NH(CH2)2–) between two azomethine nitrogen atoms; the nitrogen atom of the 3-azapentamethylene chain is free from coordination. Complex 2 has the ligand in an unusual condensation with dien: The central amino nitrogen of dien is further involved in the condensation with one C=N linkage to form an imidazolidine ring. An acetate ion bridges two copper ions to form a μ-acetato-di(μ-phenolato) dinuclear core with a saddle-like shape. The origin for the unusual condensation in 2 is considered and the physicochemical properties of 1 and 2 are examined.
  • Kunihiko Kitadai, Masashi Takahashi, Masuo Takeda, Suresh K. Bhargava, ...
    2006 Volume 79 Issue 6 Pages 886-888
    Published: 2006
    Released: June 06, 2006
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    197Au Mössbauer spectra have been measured on a series of binuclear gold complexes containing a bridging As–C ligand. The plot of quadrupole splitting (Q.S.) against isomer shift (I.S.) indicates that the gold–arsenic bond in these complexes is less covalent than the gold–phosphorus bond in analogous P–C complexes.
  • Valerii Z. Shirinian, Mikhail M. Krayushkin, Boris V. Nabatov, Ol&rsqu ...
    2006 Volume 79 Issue 6 Pages 889-893
    Published: 2006
    Released: June 06, 2006
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    A convenient preparative method of the synthesis of dithienylethenes based on maleimides was proposed. Previously, difficult accessible dithienylethene derivatives, in which 2-thienyl substituents are attached to the double bond of maleimide, have been synthesized. The spectral properties of the dithienylmaleimides were studied and it has been shown that these compounds do not belong to photochromes but they possess fluorescent properties.
  • Tsuyoshi Murata, Yasushi Morita, Kozo Fukui, Koichi Tamaki, Hideki Yam ...
    2006 Volume 79 Issue 6 Pages 894-913
    Published: 2006
    Released: June 06, 2006
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    Protonated salts and charge-transfer complexes of the 1,3- and 1,6-diazaphenalene (DAP) systems 57 have been investigated for new conducting molecule-based materials. Cyclic voltammetry measurements revealed that DAP derivatives are stronger electron donors than hydroquinone, and some of them possess comparable electron-donating abilities to TTF. X-ray crystal structure analyses of HX (X = Br and BF4) salts of 5b, 5c, and 6e confirmed their one-dimensional structures by N–H···X···H–N hydrogen bonds and their ability to form hydrogen-bonded networks in charge-transfer complexes. Actually, in the TCNQ salts of protonated 5c·H+ and 7b·H+, N–H···N≡C hydrogen-bonding interactions between DAP molecules and TCNQ molecules constructed a characteristic hydrogen-bonded cyclic tetramer and linear D–A–D triad, respectively. On the other hand, TCNQ complexes of 1,3- and 1,6-DAP derivatives, prepared by a conventional mixing method of each neutral component, were found to be partial charge-transfer complexes with segregated stacking columns as elucidated from IR and electronic spectra. Their compressed pellets exhibited high electrical conductivity (10−2–10−1 S cm−1) at room temperature with semiconducting behavior (activation energy, Ea = 40–80 meV).
  • Yasuto Uchio, Natsuki K. Kubota, Takeharu Haino, Yoshimasa Fukazawa
    2006 Volume 79 Issue 6 Pages 914-920
    Published: 2006
    Released: June 06, 2006
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    A combination of NMR analysis and molecular mechanics calculations has succeeded in the determination of the stereostructure of flexible briarane diterpenoids. The molecular mechanics calculations disclosed the multi-conformational nature of the briarane diterpenoids and gave a successful reproduction of the observed 3J coupling constants to give the correct relative configuration of each stereogenic center in these molecules. An X-ray crystallographic study of these diterpenoids supports the reliable performance of the structure elucidation of these compounds.
  • Kazuo Kurosawa, Keigo Matsuura, Toshihiko Nagase, Noritaka Chida
    2006 Volume 79 Issue 6 Pages 921-937
    Published: 2006
    Released: June 06, 2006
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    The total syntheses of stevastelins B, B3, C3, and the 5-deoxy derivative of stevastelin C3, novel cyclic depsipeptides starting from L-quebrachitol, and amino acids are described. Stereoselective introduction of two methyl groups into L-quebrachitol, followed by regioselective cleavage of the cyclohexane ring by way of the Baeyer–Villiger reaction effectively afforded the fatty acid moiety of stevastelins. Introduction of the peptide and subsequent macrolactamization gave stevastelin B. Stevastelins C3 and B3 were also synthesized by a similar way. The direct comparison of synthetic stevastelins with natural compounds revealed that the synthetic stevastelins B and B3 are identical to the natural products, confirming the proposed structures. However, the synthetic stevastelin C3 was found to not be identical with the natural product. To elucidate the structure of stevastelin C3, degradation of the natural product was carried out to show the possibility that the natural product could be a 5-deoxy derivative of the proposed structure. Thus, the 5-deoxy derivative of the fatty acid moiety was prepared and transformed into a macrocycle. The synthetic 5-deoxy compound was fully identical to natural stevastelin C3. Based on these studies, it was shown that the structure of stevastelin C3 should be revised.
  • Hiroyasu Satoh, Gaku Yamamoto, Yasuhiro Mazaki
    2006 Volume 79 Issue 6 Pages 938-943
    Published: 2006
    Released: June 06, 2006
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    Four of the title compounds, where cyclopropane, cyclobutane, cyclopentane, and cyclohexane rings are spiro-annelated at the 5-, 10-, and 15-positions of truxene, were synthesized and their spectral properties were studied. X-ray molecular structures were elucidated for the cyclopropane compound.
  • Tomikazu Kawano, Hiroki Inai, Kazuhiro Miyawaki, Ikuo Ueda
    2006 Volume 79 Issue 6 Pages 944-949
    Published: 2006
    Released: June 06, 2006
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    Cycloaromatization of the thienyl tetrayne 1, which was prepared in several steps from bis(trimethylsilyl)butadiyne and 3-bromothiophene-2-carbaldehyde, in benzene (0.33 mM) in the presence of molecular sieves 3A at room temperature gave the indeno[2,1-b]thiophene ring-fused 1H-2-benzopyran derivative 10 and indeno[2,1-b]thiophene derivative 11 in 11 and 40% yields, respectively. In contrast, cycloaromatization of 1 in the presence of water molecules at room temperature gave the indeno[2,1-b]thiophene ring-fused 1H-2-benzopyran derivative 10 and the indene ring-fused indeno[2,1-b]thiophene derivative 12 in 82 and 14% yields, respectively. Cycloaromatization of the phenyl tetrayne 9 in the presence of water molecules at room temperature also resulted in a dramatic change in product yields.
  • Lishan Zhou, Chanjuan Xi, Hui Wang, Fanzhi Kong, Tamotsu Takahashi
    2006 Volume 79 Issue 6 Pages 950-952
    Published: 2006
    Released: June 06, 2006
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    One-pot synthesis of cyclohexene derivatives from two alkynes and one maleic acid derivative could be achieved. Two alkynes were treated with [Cp2ZrBu2] to give zirconacyclopentadienes. Addition of 2 equiv of H2O followed by the reaction with maleic anhydride at 100 °C in toluene for 12 h afforded the cyclohexene derivatives in high yields. The corresponding titanacyclopentadiene did not give the desired product under the same conditions. In the case of Hf, only 8% of the product was obtained. Dienylzirconocene, which could be prepared by the addition of one equiv of EtOH or t-BuOH to the zirconacyclopentadiene, also reacted with maleic anhydride to give the cyclohexene derivative in 82 and 62% yield, respectively.
  • Eiji Fukuzaki, Shigemoto Abe, Hiroyuki Nishide
    2006 Volume 79 Issue 6 Pages 953-958
    Published: 2006
    Released: June 06, 2006
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    Hyperbranched poly[(4-methoxyphenyl-N-yloammonio)-1,2(or 4)-phenylenevinylene-1,2(or 4)-phenylene], obtained by the polycondensation of N-(4-methoxyphenyl)-N-(4-vinylphenyl)-3-bromo-4-vinylaniline and the subsequent oxidation, three-directionally satisfied the non-Kekulé-type π-conjugation and ferromagnetic connectivity of the unpaired electrons of triarylammoniumyl cationic radicals, and behaved as a high-spin organic polymer even at room temperature. The trimer model compound, N-(4-{5-[N,N-bis(4-methoxyphenyl)amino]-2-methylstyryl}-3-methylphenyl)-N-(4-{5-[N,N-bis(4-methoxyphenyl)amino]-2-methylstyryl}phenyl)-4-methoxyaniline, was synthesized from N-(4-methoxyphenyl)-N-(4-vinylphenyl)-3-methyl-4-vinylaniline. The corresponding ammoniumyl triradical displayed an average S (spin quantum number) value of 3/2, which supported the strong spin-coupling between the unpaired electrons of the ammoniumyl radicals through the π-conjugated and branched phenylenevinylene structure. Head-to-tail linkage and the branched structure of the polymer were also studied by a model reaction of N-(4-methoxyphenyl)-N-(4-vinylphenyl)-3-methyl-4-vinylaniline and bromobenzene.
  • Takakazu Yamamoto, Yoshimasa Sakai, Shinji Aramaki
    2006 Volume 79 Issue 6 Pages 959-961
    Published: 2006
    Released: June 06, 2006
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    RuII(bpy)2 complexes of poly(2-nonyl-1,10-phenanthroline-3,8-diyl) and poly(1,10-phenanthroline-3,8-diyl) acted as an n-channel in field-effect transistors (FETs), and showed electron mobility of 5.5 × 10−3 and 1.9 × 10−3 cm2 V−1 s−1, respectively. Without the Ru2+ complexation, the original poly(1,10-phenanthroline-3,8-diyl) did not behave as the n-channel active material, suggesting the enhancement of electron-accepting and electron-conducting properties of the polymer by the metal complexation.
  • Masaya Moriyama, Norihiro Mizoshita, Takashi Kato
    2006 Volume 79 Issue 6 Pages 962-964
    Published: 2006
    Released: June 06, 2006
    JOURNALS FREE ACCESS
    We report on photo-stimulated reversible association and dissociation of hydrogen bonding for self-assembled fibers comprising physical gels. The gels are formed by a hydrogen-bonded gelator containing photochromic azobenzene moieties. The photoswitching of hydrogen bonding is caused by the changes of molecular polarity for the azobenzene moieties.
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