Bulletin of the Chemical Society of Japan
Online ISSN : 1348-0634
Print ISSN : 0009-2673
ISSN-L : 0009-2673
Volume 74 , Issue 11
Showing 1-32 articles out of 32 articles from the selected issue
  • Shoji Ishizaka, Noboru Kitamura
    Type: Accounts
    2001 Volume 74 Issue 11 Pages 1983-1998
    Published: 2001
    Released: December 01, 2002
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    Structures and characteristics of water/oil interfaces at the molecular level are reviewed. Dynamic fluorescence anisotropy of Sulforhodamine 101 (SR101) and excitation energy transfer from SR101 to Acid Blue 1 (AB1) at water/oil interfaces were studied by using time-resolved total internal reflection (TIR) fluorometry. The results indicated that a water/carbon tetrachloride (CCl4) interface was sharp with respect to the molecular size of SR101 (∼10 Å), while a water/1,2-dichloroethane (DCE) interface was relatively rough compared to the water/CCl4 interface. The present results were also compared with those predicted from molecular dynamic simulations and the thermally capillary wave theory. Furthermore, on the basis of fluorescence dynamic measurements of Sulforhodamine B (SRB) adsorbed at a water/oil interface, a relationship between thickness/roughness and the polarity at the interface was discussed.
  • Takashi Kubo, Kagetoshi Yamamoto, Kazuhiro Nakasuji, Takeji Takui, Ich ...
    Type: Headline
    2001 Volume 74 Issue 11 Pages 1999-2009
    Published: 2001
    Released: December 01, 2002
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    A six-stage amphoteric redox hydrocarbon radical 3 containing three phenalenyl units was prepared. Cyclic voltammogram of 3 exhibits six reversible redox waves with a small numerical sum (E1sum) of first oxidation (E1ox) and reduction (E1red) potentials. Some redox states of 3 were successfully generated from the neutral 3 and characterized by NMR, ESR, UV-vis-NIR spectroscopies, and theoretical calculations. The spin and the charges are delocalized over the entire C3 molecule of 33+, 3•2+, 3, and 33−. On the other hand, 3•2− shows the localization of the spin on one phenalenyl unit; these results are consistent with the distorted C2 structure caused by the Jahn-Teller effect.
  • Masahisa Kakiuchi
    Type: Article
    Subject area: TP
    2001 Volume 74 Issue 11 Pages 2011-2017
    Published: 2001
    Released: December 01, 2002
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    Based on the results of hydrogen isotope fractionation in aqueous alkali halide solutions at 25 °C, reported in previous papers, the hydrogen isotope effect between water molecules hydrated to a cation or an anion and bulk water molecules is estimated with the assumption that the equilibrium constant of the hydrogen isotope exchange reaction between the hydration water of sodium ion and bulk water is unity. The orders of the hydrogen isotope effects of alkali metal cations and halide anions are found to be Cs+ > K+ > Na+ > Li+, and I > Br > Cl for a constant hydration number, respectively, and the hydrogen isotope effect is mainly influenced in anions rather than in cations. The oxygen isotope effect for alkali and halide ions is evaluated from the literature. The hydrogen and oxygen isotopic effects for the cations and anions show the same trend, but the magnitude of the hydrogen isotope effect for anions is significantly larger than that of the oxygen isotope effect.
    The free energy of transfer of alkali metal and halide ions from H2O to HDO is calculated from the hydrogen isotope effect for the individual ions. The calculated values are compared with the free energy of transfer from H2O to D2O obtained by electromotive force measurements, and are compared with the free energy of transfer from H216O to H218O calculated from the oxygen isotope effect.
  • Shin-ichi Terashita, Takashi Suzuki, Kazumi Nakatsu, Keiji Iriyama, Yu ...
    Type: Article
    Subject area: TP
    2001 Volume 74 Issue 11 Pages 2019-2023
    Published: 2001
    Released: December 01, 2002
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    To develop a possible structural model for molecular arrangement in Langmuir–Blodgett (LB) films of 2-alkyl-7,7,8,8-tetracyanoquinodimethane (alkyl-TCNQ) the molecular and crystal structures of 2-dodecyl-7,7,8,8-tetracyanoquinodimethane (dodecyl-TCNQ) have been determined by X-ray single-crystal analysis. The compound crystallizes in the triclinic space group P1- with Z = 2. The molecule consists of the planar TCNQ moiety and the dodecyl chain having all-trans conformation. In the crystals the TCNQ fragments make a stacking structure in a head-to-head manner across the centers of symmetry to form a double layer of TCNQ groups. The dodecyl chains protrude oppositely from the TCNQ layers and are assembled to form a close-packed layer, being interdigitated with each other. In this way, the TCNQ moieties and the dodecyl groups form layers alternately. This molecular arrangement in the crystal provides new insight into the structure of the LB films of alkyl-TCNQ.
  • Norihiro Kato, Yasuzo Sakai, Fujio Takahashi
    Type: Article
    Subject area: TP
    2001 Volume 74 Issue 11 Pages 2025-2029
    Published: 2001
    Released: December 01, 2002
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    The kinetic parameters of deswelling and the change of a lower critical solution temperature (LCST) for poly(N-isopropylacrylamide) gel, poly(NIPAAm) gel, were investigated in the presence of glucose and other sugars as hydrophilic probes. The enthalpy of activation (ΔH) and the entropy of activation (ΔS) for deswelling were influenced by the concentration of additive sugars. Plots of ΔH against TΔS fell on a straight line, of which the slope was approximately 0.91–0.94. This result shows a compensation effect of the free energy of activation (ΔG) concerning the relationship between ΔH and ΔS for deswelling of poly(NIPAAm) gel. The molecular interaction between sugar and water clusters involved with the polymer is responsible for the compensation effect between ΔH and ΔS. The equatorial hydroxy groups of sugar molecules interact easily with water clusters around the hydrophobic isopropyl groups (the iceberg) to form hydrogen bonds, which give rise to change the situation of polymer hydration. A decrease of the LCST has close connections with the number of equatorial hydroxy groups of sugars as additives. The LCST decrease in sugar solutions was regarded as the situation change of polymer hydration in the iceberg.
  • Tatsuyuki Yamamoto, Takuya Nagata, Hideki Ohtsuki, Masaharu Ono, Yoshi ...
    Type: Article
    Subject area: TP
    2001 Volume 74 Issue 11 Pages 2031-2035
    Published: 2001
    Released: December 01, 2002
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    Substitution of the pyridinio groups for the C(6)-OH’s of cyclodextrins (CD’s) brought about a remarkable increase in the binding constants (Ka) for 1 : 1 complexes of CD’s with inorganic anions, such as I, SCN, and ClO4. The thermodynamic parameters for the complexation of native α-CD and its pyridinio derivatives showed that the increase in Ka is mainly driven by an enthalpy term (ΔH), and that the contribution of an entropy term (TΔS) is minor. In contrast, the increase in Ka is mainly driven by TΔS, and the contribution of ΔH is minor, for the systems of β- and γ-CD’s with the larger interior cavities. These results were explained in terms of the combined action of van der Waals and electrostatic interactions between the CD’s and anions, together with desolvation upon complexation.
  • Ikuo Tokue, Masaaki Kobayashi, Takeyuki Kudo, Katsuyoshi Yamasaki
    Type: Article
    Subject area: TP
    2001 Volume 74 Issue 11 Pages 2037-2043
    Published: 2001
    Released: December 01, 2002
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    The photoemissions from fragments produced by collisions of He(23S) atoms with CHCl3, CCl2F2, CCl3F, CCl4, and CBrCl3 have been studied in the collision energy range of 120–210 meV using a crossed beam. The Cl2(D′–A′) band is predominant for CCl4 and CBrCl3, while the A–X and B–X bands of CF are intense for CCl2F2 and CCl3F. The sum of the emission cross sections (σem) for several systems of neutral fragments in the 190–600 nm region was estimated to be in the (0.3–1.2) × 10−20 m2 range for these chloromethanes at a collision energy of 150 meV. The dependences of σem’s for the Cl2(D′–A′) band from CHCl3 and CCl4 on the collision energy are either nearly zero or slightly negative. The sum of σem’s for Cl2 and other ion-pair bands reveals a fairly good correlation with the electron affinity of the targets. These results support the harpoon mechanism for the formation of Cl2(D′) from the He(23S) + chloromethanes reactions.
  • Eiji Fujimori, Kenji Ichikawa, Ryuji Shiozawa, Katsuichi Asai, Koichi ...
    Type: Article
    Subject area: AI
    2001 Volume 74 Issue 11 Pages 2045-2051
    Published: 2001
    Released: December 01, 2002
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    The multielement determination of major-to-ultratrace elements in industrial waste incineration bottom ash was carried out by inductively coupled plasma atomic emission spectrometry (ICP-AES) and inductively coupled plasma mass spectrometry (ICP-MS) after alkali fusion using LiBO2. The concentrations of 50 elements in bottom ash could be determined over the concentration range from 192 mg g−1 of Si to 0.072 μg g−1 of In. Silicon, Al, Fe, Ca, Na, and Ti, which except for Fe are lithophile elements, were major elements of industrial waste incineration bottom ash. The distributions of major-to-ultratrace elements in incineration bottom ash were evaluated by the enrichment factors. The enrichment factors of major elements in incineration bottom ash indicated that their relative contents were quite similar to those in the continental crust. It was also found that most minor and trace elements in the lithophile element group provided almost the same enrichment factors as those of major elements. On the other hand, Cu, Zn, Cd, and Pb in the chalcophile element group as well as some of the siderophile ones, such as Co and Ni, provided the significantly larger enrichment factors, although they were more enriched in fly ash than in bottom ash. Such large abundances of many transition elements in industrial waste incineration ashes may reflect the large amounts of metal use in industry as well as in modern society.
  • Priya V. Jaiswal , Vijaykumar S. Ijeri , Ashwini K. Srivastava
    Type: Article
    Subject area: AI
    2001 Volume 74 Issue 11 Pages 2053-2057
    Published: 2001
    Released: December 01, 2002
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    Cyclic voltammograms at the carbon paste electrode were recorded for menadione or vitamin K3 dissolved in aqueous surfactant solutions above their critical micellization concentrations. The reduction and oxidation potentials of the vitamin were found to be different in different surfactants and were found also to vary with change in the surfactant concentration. Differential pulse voltammetric technique was utilized for the determination of the vitamin in the above surfactant systems. The limit of detection and the linear range varied in different surfactants, the lowest being in the sodium dodecyl sulfate surfactant systems. Similarly, cyclic voltammograms were recorded for ascorbic acid and the effect of various surfactants on its oxidation peak was also studied. Simultaneous determination of menadione, ascorbic acid, and riboflavin was attempted. Synthetically prepared samples were analyzed and gave satisfactory results.
  • Tatsuaki Sakano, Masaki Horie, Kohtaro Osakada, Hidenobu Nakao
    Type: Article
    Subject area: AI
    2001 Volume 74 Issue 11 Pages 2059-2065
    Published: 2001
    Released: December 01, 2002
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    The reactions of 1,1′-bis(hydroxymethyl)ferrocene with primary amines such as 6-aminohexanol, cyclohexylamine, 4-phenylbutylamine, 2-isopropylaniline, 4-(trifluoromethyl)benzylamine, and 1-aminomethylferrocene in the presence of [RuCl2(PPh3)3] catalyst led to intermolecular condensation of the CH2OH and NH2 groups to afford N-alkyl- or N-aryl substituted 2-aza-[3]-(1,1′)-ferrocenophanes. Cyclic voltammograms of the obtained N-alkyl-2-aza-[3]-(1,1′)-ferrocenophanes exhibit reversible redox of the Fe center at E1/2 = −0.01 – +0.04 V (vs Ag+/Ag) and subsequent irreversible oxidation of the amino group of the ligand at Eox = 0.41–0.44 V. N-(4-Hydroxyphenyl)-2-aza-[3]-(1,1′)-ferrocenophane shows two pairs of reversible electrochemical oxidation and reduction at E1/2 = 0.04 and 0.44 V. The latter potential is significantly lower than the corresponding electrochemical oxidation of N-aryl-2-aza-[3]-(1,1′)-ferrocenophanes (0.68–0.75 V). The N-alkyl-2-aza-[3]-(1,1′)-ferrocenophanes react with MeI to cause methylation of the amino group to produce cationic 2-aza-[3]-(1,1′)-ferrocenophanes containing a quaternary nitrogen center. The iodo counter anion is easily replaced with BF4 or PF6. Cyclic voltammograms of the cationic ferrocenophanes show the redox between ferrocene and ferrocenium at E1/2 = 0.37–0.42 V.
  • Deqing Zhang, Liang Ding, Wei Xu, Junling Yang, Xianglin Jin, Daoben Z ...
    Type: Article
    Subject area: AI
    2001 Volume 74 Issue 11 Pages 2067-2073
    Published: 2001
    Released: December 01, 2002
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    Two new copper(I) iodide coordination compounds [Cu2I2(p-PYNN)4] (1) and [Cu4I4(m-PYNN)4] (2), where p-PYNN and m-PYNN are 4,4,5,5-tetramethyl-2-(4-pyridyl)-4,5-dihydro-1H-imidazol-1-oxy-3-oxide and 4,4,5,5-tetramethyl-2-(3-pyridyl)-4,5-dihydro-1H-imidazol-1-oxyl-3-oxide, respectively, were synthesized and characterized. They both were found to be fluorescent. Their crystal structures were determined: 1, triclinic, space group P1-, a = 13.668(3) Å, b = 14.280(3) Å, c = 7.273(1) Å, α = 90.18(3)°, β = 101.86(3)°, γ = 91.09(3)°, Z = 1, R = 0.0310 (Rw = 0.0805) for 4217 observed reflections with I ≥ 2σ(I); 2, triclinic, space group P1-, a = 15.569(9) Å, b = 16.247(7) Å, c = 15.103(9) Å, α = 94.48(5)°, β = 116.15(5)°, γ = 83.07(5)°, Z = 2, R = 0.0686 (Rw = 0.1933) for 8311 observed reflections with I ≥ 2σ(I). Magnetic studies indicated that 1 showed ferromagnetic behavior, while 2 displayed antiferromagnetic properties. Discussions about the relationship between their crystal structures and magnetic properties are also presented.
  • Masaaki Haneda, Shin-ichi Ohzu, Yoshiaki Kintaichi, Ken-ichi Shimizu, ...
    Type: Article
    Subject area: AI
    2001 Volume 74 Issue 11 Pages 2075-2081
    Published: 2001
    Released: December 01, 2002
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    Catalytic reduction of NO by propene in the presence of oxygen was studied over Sn–Al2O3 prepared by the sol–gel method. The maximum NO conversion did not change much with Sn loading (1–5 wt%), although the effective temperature window for NO reduction shifted to lower temperatures with increasing Sn loading. X-ray diffraction (XRD), and X-ray absorption spectroscopy (XANES and EXAFS) revealed the formation of finely-divided SnO2 crystallites in Sn–Al2O3. It was deduced that not only the surface vicinity of supported SnO2, which can be reduced at lower temperatures, but also alumina participate in the reaction as catalytically active sites. The catalytic performance of Sn–Al2O3 was markedly improved by an H2O treatment at 873 K. The H2O treatment did not affect the crystal structure of the catalysts and the dispersion state of supported SnO2, but promoted the removal of Cl ions, which originated from the SnCl4 precursor. The activity enhancement by the H2O treatment was accounted for by an increase in the surface SnO2 concentration as active sites and by the modification of oxo-tin species as active sites. Reaction kinetic studies suggested that NO reduction on the fresh and the H2O-treated catalysts proceeds through the same reaction pathway in which the surface NOx adspecies and C3H6-derived species play an important role for NO reduction.
  • Toshio Takayanagi, Shoji Motomizu
    Type: Article
    Subject area: AI
    2001 Volume 74 Issue 11 Pages 2083-2089
    Published: 2001
    Released: December 01, 2002
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    Binding constants of 13 kinds of phenols as neutral and anionic species to nonionic surfactant micelles were determined using their mobility changes in capillary zone electrophoresis. Electrophoretic mobility of the phenolate ions at alkaline regions decreased with increasing the concentrations of nonionic surfactant. Analyzing such mobility decreases provided the binding constants of the ions (KB,A). The KB,A values are larger in the anions which are more hydrophobic. Binding constants of the phenols as their neutral species to nonionic surfactant micelles (KB,HA) were also determined by using the difference in acid dissociation constants between in the absence of and in the presence of nonionic surfactant micelles: in the presence of the surfactant, the apparent pKa values became larger, which indicates that the neutral species are more likely bound to the micelles. The KB,A and KB,HA values determined were compared with each other on the basis of hydrophobicity, basicity, and position of the substituents.
  • Hideki Sugimoto, Chikako Matsunami, Chikako Koshi, Mikio Yamasaki, Kei ...
    Type: Article
    Subject area: AI
    2001 Volume 74 Issue 11 Pages 2091-2099
    Published: 2001
    Released: December 01, 2002
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    A series of the complexes, [MCl2(L)]+ (M = Ru, L = tpa (1), Metpa (1a); M = Os, L = tpa (2); M = Re, L = tpa (3), Metpa (3a); tpa = tris(2-pyridylmethyl)amine, Metpa = ((6-methyl-2-pyridylmethyl)bis(2-pyridylmethyl)amine), have been prepared. X-ray structural analyses of the series of isostructural complexes [1a]BF4, [2]PF6·C2H5OC2H5, [3]BF4, and [3a]BF4 together with that of the previously reported [1]ClO4, made detailed comparison of structure parameters for Ru, Os, and Re possible. The corresponding metal-ligand bond lengths which are similar between [1]ClO4 and [2]PF6·C2H5OC2H5 are considerably longer (0.02–0.03 Å) for [3]BF4, especially in the case of M–N(tertially nitrogen) (0.06 Å) bond. The M–Cl(trans to tertially nitrogen) bond lengths do not follow this trend. Introduction of the methyl group causes significant influence on the structure of the Re(III) complex: increase in bond length of Re–N(methylated pyridyl) and Re–N(pyridyl) trans to it. Bond angles around the metal ion related to the methylated pyridyl group are also significantly affected. Such steric influence is not clear for [1a]BF4 due to disorder of methyl group. The redox waves of the two processes, M(II/III) and M(III/IV), are observed for all the complexes. The redox potentials for individual process follow the order: Ru < Os < Re (from negative to positive), the difference being ca. 0.5 V. The difference in the two consecutive redox potentials is almost identical (ca. 1.6 V) among the three metal ions, suggesting that the stabilities of the trivalent oxidation state over di- and tetravalent ones are not affected by the different d-electron configurations. Strong visible MLCT bands are observed only for the rhenium(III) complexes. This may be due to higher d-orbital energies of the rhenium(III) ion as evidenced from the redox potentials.
  • Masanobu Tsuchimoto
    Type: Article
    Subject area: AI
    2001 Volume 74 Issue 11 Pages 2101-2105
    Published: 2001
    Released: December 01, 2002
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    Polymeric and dimeric forms of an oxotitanium(IV) complex with a tetradentate Schiff base ligand, [TiO (salen)]·0.33CH3OH (1) (H2salen: N,N′-disalicylidene-1,2-ethanediamine) and [{TiO(salen)}2]·2DMF (2), were prepared by the reaction of the Schiff base ligand with [{TiO(acac)2}2] (H2acac: acetylacetone) in methanol and in DMF, respectively. X-ray crystal structure analyses of both complexes were carried out. Complex 1 has a linear ···Ti=O···Ti=O··· chain structure with the Ti=O and O···Ti distances being 1.705(2)–1.706(2) and 2.095(2)–2.134(2) Å, respectively. Complex 2 has a dimeric di-μ-oxo structure with the Ti–O distances being 1.804(2) and 1.907(2) Å. A strong band at 744 cm−1 in the IR spectrum of 1 was assigned unambiguously to the Ti=O stretching band by an 18O-labelling experiment.
  • Heitaro Yamane, Yasuo Nakao, Satoru Kawabe, Yong Xie, Nobuko Kanehisa, ...
    Type: Article
    Subject area: AI
    2001 Volume 74 Issue 11 Pages 2107-2112
    Published: 2001
    Released: December 01, 2002
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    New dinuclear nickel(II) complexes ([Ni2(L-Et)(CH2ClCOO)(H2O)2](ClO4)2·H2O (3), [Ni2(L-Et)(CCl3COO)(H2O)2](ClO4)2·H2O (4), [Ni2(L-Et)(CF3COO)(H2O)2](ClO4)2·3H2O (5)) and their urea complexes ([Ni2(L-Et)(RCOO)(ur)(H2O)](ClO4)2 (R = CH3 (6), C2H5 (7), CH2Cl (8), CCl3 (9), CF3 (10)) (HL-Et = N,N,N′,N′-tetrakis[(1-ethyl-2-benzimidazolyl)methyl]-2-hydroxy-1,3-diaminopropane and ur = urea) have been prepared in order to model the active site urease. These complexes were characterized by IR and UV-vis spectra, and by magnetic susceptibilities. The crystal structures of the complexes [Ni2(L-Et)(CH2ClCOO)(CH3OH)2](ClO4)2 (3′) and [Ni2(L-Et)(OAc)(ur)(H2O)](ClO4)2· 2(CH3)2CO (OAc = acetate) (6′) were determined by X-ray crystallography. In the cation of 6′, the two nickel(II) ions are bridged by an alkoxo of L-Et and an acetato, and a monodentate urea molecule is attached to a nickel(II) through its oxygen atom. Variable temperature magnetic susceptibility measurements of the urea complexes 6, 8, and 10 show an antiferromagnetic exchange coupling (2J = −15.8, −8.0, and −13.3 cm−1 for 6, 8, and 10, respectively, Hamiltonian H = −2JS1·S2 with S1 = S2 = 1) between two nickel(II) ions.
  • Kan Kanamori, Ayako Kyotoh, Kazuya Fujimoto, Kiyonori Nagata, Honoh Su ...
    Type: Article
    Subject area: AI
    2001 Volume 74 Issue 11 Pages 2113-2118
    Published: 2001
    Released: December 01, 2002
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    Vanadium(III) complexes with the hexadentate ligand, tetramethylenediamine-N,N,N′,N′-tetraacetate (tmdta), N,N′-bis(2-pyridylmethyl)-1,2-ethanediamine-N,N′-diacetate (bpedda), and N,N′-bis(2-pyridylmethyl)-1,3-propanediamine-N,N′-diacetate (bppdda), have been prepared. The structures of the tmdta (1) and bpedda (3) complexes have been determined by X-ray crystallography. The stereochemical property of complex 1 was compared with that of the corresponding Cr(III) complex (2), whose structure was also determined by X-ray crystallography. The tmdta complexes adopt a distorted octahedral structure, including a seven-membered chelate ring formed by the tetramethylenediamine moiety of the tmdta ligand. The bpedda complex has been determined to be a heptacoordinate complex with a distorted pentagonal bipyramidal geometry. The isolated bppdda complex has been characterized to be a μ-oxo dinuclear vanadium(III) complex on the basis of its spectral features. The tmdta and bpedda complexes do not yield a corresponding μ-oxo dinuclear vanadium(III) complex on base hydrolysis.
  • Yasushi Ougitani, Tatuya Aizawa, Noriyuki Sonoyama, Tadayoshi Sakata
    Type: Article
    Subject area: AI
    2001 Volume 74 Issue 11 Pages 2119-2122
    Published: 2001
    Released: December 01, 2002
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    The temperature dependence of the probability of chain growth was studied for hydrocarbons formed at Fe and Ni electrodes by electrochemical CO2 reduction. The faradaic efficiency for hydrocarbons increased with increasing temperature. The distribution of the produced hydrocarbons followed well the Schultz Flory equation. The probability of chain growth increased with increasing temperature. Based on the temperature dependence of the probability of chain growth, the mechanism of the electrochemical Fischer Tropsch reaction is discussed.
  • Tetsuya Yanagimoto, Akito Nakagawa, Teruyuki Komatsu, Eishun Tsuchida
    Type: Article
    Subject area: AI
    2001 Volume 74 Issue 11 Pages 2123-2128
    Published: 2001
    Released: December 01, 2002
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    An amphiphilic (tetraphenylporphyrinato)iron(III) derivative with four alkylphosphocholine groups and a proximal imidazole [(lipidporphyrinato)iron(III); 1a] was self-assembled in phosphate-buffered saline (pH 7.3, [NaCl] = 0.15 M) to form spherical micelles with a diameter of 10 nm. The obtained solution showed a distinct absorption band at 362 nm, which was assigned to the ligand-to-metal [Cl to iron(III)] charge transfer (LMCT) transition. Light irradiation into this CT band under an Ar atmosphere did not induce any changes in the UV-vis absorption spectrum. On the other hand, the addition of glucose (150 mM) to the solution led to complete photoreduction of the central iron(III) ion, giving a five-N-coordinated high-spin iron(II) complex. It has also been found that a small excess amount of hyaluronic acid ([units] = 100 µM) showed the same effect. The photoreduction was only seen by LMCT irradiation in the presence of the saccharide. It probably occurred via intramolecular electron transfer from Cl to iron(III), and the produced chlorine radical was scavenged by the saccharide, which prevented a back electron transfer reaction (the quantum yields; ca. 0.007). Interestingly, hyaluronic acid changed the morphology of the 1a assembly from the micelle to a thin fiber. This co-aggregated structure with hyaluronic acid would be responsible for the effective photoreduction of 1a. The viscosity of the fiber solution significantly decreased during the photoreduction, which suggests that radical trapping induces depolymerization of the hyaluronic acid. Laser flash photolysis experiments showed that the reduction and the imidazole association to the iron(II) center are completed within 50 ns after a laser pulse. The photoreduced (lipidporphyrinato)iron(II) fibers can reversibly bind and release O2 similar to the same fibers which were prepared by chemical reduction using ascorbic acid.
  • Yasuyoshi Sayama, Makoto Handa, Masahiro Mikuriya, Ichiro Hiromitsu, K ...
    Type: Short Articles
    Subject area: AI
    2001 Volume 74 Issue 11 Pages 2129-2130
    Published: 2001
    Released: December 01, 2002
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    A ruthenium(II,III) pivalate dimer axially coordinated by a nitroxide radical and a water molecule, [Ru2(O2CC-Me3)4(nitph)(H2O)]BF4 (nitph = 2-phenyl-4,4,5, 5-tetramethyl-4,5-dihydro-1H-imidazolyl-1-oxyl 3-N-oxide), has been prepared and characterized. The magnetic interaction between the Ru(II,III) core and the radical through the coordinated N–O group was estimated to be J = −45 cm−1.
  • Jong-Wan Lim, Masahiro Mikuriya, Hiroshi Sakiyama
    Type: Short Articles
    Subject area: AI
    2001 Volume 74 Issue 11 Pages 2131-2132
    Published: 2001
    Released: December 01, 2002
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    A cobalt(II) complex with bis[2-(3,5-dimethylpyrazol-1-yl)ethyl][(pyrazol-1-yl)methyl]amine (bppa), [CoCl(bppa)][B(C6H5)4]·C2H5OH, was synthesized and characterized by measurements of the magnetic moment and the electronic spectra. The X-ray crystal structure shows that the compound has a distorted trigonal bipyramid with a N4Cl coordination environment.
  • Sabir Hussain Mashraqui, Sukeerthi Kumar, Chandrasekhar Dayal Mudaliar
    Type: Article
    Subject area: OB
    2001 Volume 74 Issue 11 Pages 2133-2138
    Published: 2001
    Released: December 01, 2002
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    The feasibility of aqueous micelles of cetyltrimethylammonium bromide in catalyzing C–N bond formation has been studied with respect to N-alkylations of benzotriazole (Bt). Alkylations with various alkylating agents and the addition of Bt across activated double bonds in the Michael fashion occurred successfully in fair-to-good yields in the aqueous micellar regime. These reactions provided a mixture of N-1 and N-2 alkylated products, with a marked preference for N-1 over N-2 isomers. Micellar catalysis has been evaluated experimentally to indicate over a 50% micellar contribution to these alkylations in contrast to their aqueous counterparts. Since, N-alkyl benzotriazoles are of potential biological interest, the present micellar procedure offers a convenient alternative to other available methods.
  • Taketo Ikeno, Mitsuo Sato, Hiroyuki Sekino, Asae Nishizuka, Tohru Yama ...
    Type: Article
    Subject area: OB
    2001 Volume 74 Issue 11 Pages 2139-2150
    Published: 2001
    Released: December 01, 2002
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    Highly enantioselective cyclopropanation of styrene derivatives and diazoacetates was effectively catalyzed by reasonably designed 3-oxobutylideneaminatocobalt(II) complexes, whose ligands were prepared from 1,2-dimesitylethylenediamine and alkyl 3-oxobutanoates. The steric demand of the diamine unit of the complexes seriously influenced the enantioselectivity, and the ester groups on their side chains somewhat improved the trans-selectivity. Addition of a catalytic amount of N-methylimidazole significantly accelerated the reaction and enhanced the enantioselectivity due to its coordination to the center cobalt atom of the complex as an axial ligand. Alcoholic or aqueous alcoholic solvents were also effective particularly for the cyclopropanation of 1-substituted 1-phenylethylenes to achieve high enantioselectivity in aqueous methanol.
  • Taketo Ikeno, Izumi Iwakura, Tohru Yamada
    Type: Article
    Subject area: OB
    2001 Volume 74 Issue 11 Pages 2151-2160
    Published: 2001
    Released: December 01, 2002
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    A semiempirical analysis using the PM3(tm) method was performed on the 3-oxobutylideneaminatocobalt(II) complexes-catalyzed cyclopropanation. Although the energy diagram calculated by the PM3(tm) method had a contradiction, where the product was less stable than the reactant, the structures and the energies of the reactant and the transition state obtained by the PM3(tm) method could be relatively reliable by comparing with the results based on the density functional theory. Analysis of the transition states by the PM3(tm) method indicated that the olefin approached parallel to the cobalt-carbene bond with bisecting an O1–Co–O2 angle. It was revealed that the transition state affording the (1S,2S)-arylcyclopropanecarboxylic acid ester corresponding to the (1S,2S)-cobalt complex was the most stable, because of the lowest steric repulsion among the aryl group of the diamine unit, the ester moiety, and the approaching olefin. It was clarified that the enantioselectivity occurred due to the repulsion between the aryl group of the diamine unit and the ester moiety and that the diastereoselectivity was controlled by the repulsion between the ester moiety and the approaching olefin.
  • Yuriko Nitta, Takeshi Kubota, Yasuaki Okamoto
    Type: Article
    Subject area: OB
    2001 Volume 74 Issue 11 Pages 2161-2165
    Published: 2001
    Released: December 01, 2002
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    The enantioselective hydrogenation of the C=C double bonds in (E)-2-methyl-2-butenoic acid, (E)-2-methyl-2-pentenoic acid, and (E)-2,3-diphenyl-2-propenoic acid has been studied using cinchonidine-modified Pd/TiO2 catalysts with different metal loadings of between 0.5 to 30 wt%. For all of the substrates examined, those catalysts with degrees of Pd dispersion lower than 0.2 have been shown to be rather detrimental for obtaining a high enantioselectivity, as opposed to the tendencies reported for the hydrogenations of keto esters with modified Pt and Ni systems. The hydrogenations of the aliphatic acids are almost structure insensitive with a slight decrease in the enantioselectivity at Pd dispersions lower than 0.2, which is in great contrast to the hydrogenation of the aromatic acid. A similar difference in the structure sensitivity has been observed with catalysts modified by a larger modifier, (−)-dihydroapovincaminic acid ethyl ester. The influence of the substrate structure on the adsorption mode and the strength of the modifier-substrate complex is discussed in relation to the size of the Pd ensemble on the catalyst surface.
  • Shigehisa Akine, Kei Goto, Takayuki Kawashima
    Type: Article
    Subject area: OB
    2001 Volume 74 Issue 11 Pages 2167-2174
    Published: 2001
    Released: December 01, 2002
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    The conformational mobility of the bridged calix[6]arenes with allyl and ethyl groups at the lower rim was investigated. Allylation of the tetrahydroxy compounds afforded two isomers: 5a (cone) and 5b (1,2,3-alternate), which were separated by silica-gel chromatography. These isomers underwent slow isomerization at room temperature with a half-life time of about 2 weeks. On the other hand, the ethyl derivatives 69 were found to exist as mixtures of conformational isomers in solution; they were observed independently on the NMR time-scale but were inseparable on the laboratory time-scale. The ratios of two isomers of 69 depended on the functionality on the bridging unit, the effects of which were investigated by molecular mechanics calculations. In the crystalline state, the ethyl derivative 6 with a bromo functionality was found to take the 1,2,3-alternate conformation, while compound 7 with an ethynyl group adopted the cone conformation.
  • Kaoru Harada, Yoshimi Ito, Toshinori Wada, Toratane Munegumi
    Type: Article
    Subject area: OB
    2001 Volume 74 Issue 11 Pages 2175-2179
    Published: 2001
    Released: December 01, 2002
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    Introduction of argon-arc plasma into an aqueous solution of formic acid resulted in the formation of oxalic acid. The reaction conditions for the dimerization were studied. The maximum yield of oxalic acid reached 47–50% when the reaction was carried out using sodium formate or calcium formate. Dimerization of acetic acid was also examined.
  • Tomoyuki Okuyama, Yayoi Yokoyama, Yasushi Yokoyama
    Type: Article
    Subject area: OB
    2001 Volume 74 Issue 11 Pages 2181-2187
    Published: 2001
    Released: December 01, 2002
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    While the association constant of the colored form of a thermally irreversible photochromic indolylfulgimide with 2, 6-bis (octanoylamino)pyridine in toluene at 21 °C was 156 ± 11 mol−1 dm3 through triplex hydrogen bonding, that of its colorless form, generated by visible-light irradiation, was increased to 885 ± 63 mol−1 dm3. This result was supported by PM3 semiempirical molecular–orbital calculations that the difference of the association constants between the C-form and the E-form was mainly due to differences in the structures and conformations of the imide moiety.
  • Koichi Fukase, Teruo Kirikae, Fumiko Kirikae, Wen-Chi Liu, Masato Oika ...
    Type: Article
    Subject area: OB
    2001 Volume 74 Issue 11 Pages 2189-2197
    Published: 2001
    Released: December 01, 2002
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    Both endotoxic and antagonistic [3H]-labeled 2-(phosphonooxy)ethyl (PE) analogs of lipid A were synthesized with high purity and high specific radioactivity. Lipid A-binding proteins were detected by using the endotoxic analog of hexaacyl Escherichia coli-type designated [3H] PE-506. The plasma membrane fractions from peritoneal macrophages derived from LPS-responder C3H/HeN mice and LPS-hyporesponder C3H/HeJ mice were separated by SDS-PAGE and transferred onto nitrocellulose membranes. The membranes were then incubated with the [3H] PE-506. Several [3H] PE-506 binding proteins were detected in both C3H/HeN and C3H/HeJ macrophages. Unlabeled hexaacyl lipid A inhibited the interaction between [3H] PE-506 and these proteins. The result suggests that there exist multiple binding sites for lipid A on macrophages. LPS-induced change in the profile of the cell surface lipid A binding proteins was observed in C3H/HeN macrophages, but not in C3H/HeJ macrophages, by preincubation of macrophages with LPS.
  • Noriaki Yamauchi, Satoshi Endoh, Keiko Kato, Tatsushi Murae
    Type: Article
    Subject area: OB
    2001 Volume 74 Issue 11 Pages 2199-2205
    Published: 2001
    Released: December 01, 2002
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    We examined the incorporation of lysine into archaeal isoprenoidal lipids of halophilic archaea, Natrinema pallidum and Halobacterium halobium using two regiospecifically deuterium-labeled derivatives, [3,3-2H2] and [6,6-2H2]lysines. The two deuterated lysines were synthesized, and the incorporation of deuterium to the lipid core was defined by 2H NMR. The results revealed that lysine is degraded to crotonoyl-CoA by the decarboxylation of carboxylate in the metabolism of halophilic archaea, much like the metabolism of lysine in aerobic bacteria; the process converts lysine to isoprenoidal lipids via the mevalonate pathway through glutaryl-CoA, crotonoyl-CoA, and acetoacetyl-CoA.
  • Yingmo Hu, Yui Ishikawa, Katsuyuki Hirai, Hideo Tomioka
    Type: Article
    Subject area: OB
    2001 Volume 74 Issue 11 Pages 2207-2218
    Published: 2001
    Released: December 01, 2002
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    A series of diazobis(2,6-dimethylphenyl)methanes (1) bearing eight symmetrical para di-substituents have been prepared and photolyzed to generate the corresponding carbenes (2). Product analysis studies showed that carbenes (2) decay mainly either by dimerization to form tetra(aryl)ethylene (3) or by attack at an o-methyl group to afford 1,2-dihydrobenzocyclobutenes (4) by way of o-quinodimethanes (6) in solution. The zero-field splitting parameters, D and E, were measured in matrices of different viscosities and are analyzed in terms of a sigma-dot (σ) scale of spin-delocalization substituent constants. Fairly good correlation with σ was found for the D values of 32 in its minimum energy geometry. Stabilities of 32 were estimated either by measuring the temperature at which the triplet carbene signals disappeared upon thawing the matrix or by analyzing the decay kinetics of 32 in a degassed solution at room temperature. They are examined in terms of the D values in matrix at low temperature and in terms of product distributions in solution at room temperature.
  • Yoshio Aoki, Hiroaki Shitara, Takuji Hirose, Hiroyuki Nohira
    Type: Article
    Subject area: AM
    2001 Volume 74 Issue 11 Pages 2219-2222
    Published: 2001
    Released: December 01, 2002
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    New chiral dopants for nematic liquid crystals were synthesized using optically active 2-phenylpropanoic acid derivatives. The magnitude of the helical twisting power (HTP) was largely influenced by the terminal group of the asymmetric frame and the core structures. (S)-1-[4-(trans-4-Butylcyclohexyl)phenyl]-2-phenylpropane-1-one showed a large HTP value (20.4 µm−1). The relationship between the HTP and the molecular structures of the chiral dopants is discussed.
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