Bulletin of the Chemical Society of Japan
Online ISSN : 1348-0634
Print ISSN : 0009-2673
ISSN-L : 0009-2673
68 巻 , 2 号
選択された号の論文の34件中1~34を表示しています
  • Hiroshi Yamashita, Masato Tanaka
    1995 年 68 巻 2 号 p. 403-419
    発行日: 1995年
    公開日: 2006/07/05
    ジャーナル 認証あり
    Si–H and Si–Si bonds are efficiently transformed by early and late transition metal catalyses that involve possible key elemental steps, such as σ-bond metathesis, the oxidative addition of Si–H and Si–Si bonds, insertion of unsaturated compounds into silylmetals, the reductive elimination of Si–Si and Si–C bonds, and silylene generation via α-substituent migration in silylmetal species. These catalyses have enabled us to develop a dehydrogenative poly/oligosilane formation from hydrosilanes, oligosilane formation via a redistribution of hydrodisilanes, silylene-phenylene polymer synthesis via a redistribution of bis(trihydrosilyl)benzene, and (step-)ladder polycarbosilane synthesis by a dehydrogenative double silylation of diynes with a tetrakis(hydrosilyl)benzene. Insertion of unsaturated compounds (acetylenes, quinones, etc.) into Si–Si bonds of polymer backbones provides a new methodology for the modification/synthesis of silicon polymers. Cyclooligosilanes and cyclic disilanes undergo ring-opening copolymerization with p-quinones to give silylene and arylenedioxy unit-containing polymers. Other relevant processes as well as some chemical and physicochemical properties (ceramization, electric conductivity, thermal stability, etc.) of the resulting polymers are also described.
  • Munetaka Akita, Yoshihiko Moro-oka
    1995 年 68 巻 2 号 p. 420-432
    発行日: 1995年
    公開日: 2006/07/05
    ジャーナル 認証あり
    A variety of polymetallic C2 (C2 and C2H) complexes are prepared by structure expansion of parent metal acetylide complexes, Fp*–C≡C–H (1) and Fp*–C≡C–Fp* (2) [Fp* = (η5–C5Me5)Fe(CO)2], and their structure and reactivity have been investigated as models for surface-bound C2 species formed during catalytic CO hydrogenation. The results summarized here involve (1) intramolecular 1,2-H shift of the C2H complexes relevant to the 1-alkyne-to-vinylidene rearrangement within a metal coordination sphere, (2) electronic influence of metal centers on the structure of dinuclear bridging alkynyl complexes, (3) conversion of the C2 moiety into various C2 functional groups, and (4) synthesis of higher nuclearity dicarbide (C2) cluster compounds with novel coordination structure by sequential addition reactions of metal fragments and direct coupling of a preformed low-nuclearity cluster structure.
  • Akio Yamamoto
    1995 年 68 巻 2 号 p. 433-446
    発行日: 1995年
    公開日: 2006/07/05
    ジャーナル 認証あり
    After a brief introduction summarizing the author’s previous work concerning the double carbonylation of aryl halides catalyzed by palladium complexes, newly found catalytic processes (1) for converting allylic formates and chlorides into β,γ-unsaturated acids and (2) the double carbonylation of allylic chlorides to β,γ-unsaturated α-keto amides are described. Mechanisms which reasonably account for the catalytic processes are proposed on the basis of studies concerning the properties of the organopalladium complexes.
  • Hiroki Fujimori, Hiroaki Fujita, Masaharu Oguni
    1995 年 68 巻 2 号 p. 447-455
    発行日: 1995年
    公開日: 2006/07/05
    ジャーナル 認証あり
    Irreversible enthalpy-relaxation processes were tracked under a constant temperature condition by the temperature jump method for liquid 1,3-diphenyl-1,1,3,3-tetramethyldisiloxane with an adiabatic calorimeter, and simulated based on a double-well potential model with a computer. The processes were observed to show remarkable nonexponentialities and were characterized in terms of a stretched exponential function. The nonexponentiality parameter (β) depended strongly on the magnitude of the temperature jump, indicating the nonlinearity of the relaxation processes. The results of the nonlinearity parameter (δ) combined with those of 1,2-propanediol and glycerol indicated that the nonlinearity originated primarily due to the fragility of the liquid, namely the non-Arrhenius property of the relaxation times. The degree of the nonlinearity was smaller in the endothermic processes than in the exothermic ones. The difference is discussed based on the results of a computer simulation.
  • Ryoichi Hazama, Keisuke Umakoshi, Akio Ichimura, Shinji Ikari, Yoichi ...
    原稿種別: Accounts
    専門分野: AI
    1995 年 68 巻 2 号 p. 456-468
    発行日: 1995年
    公開日: 2006/07/05
    ジャーナル 認証あり
    Four new dinuclear oxomolybdenum(V) and oxotungsten(V) complexes, [M2O2(μ-O)2(μ-tpen-N,N′)]2+ and [M2O2(μ-O)2(μ-tppn-N,N′)]2+ (tpen = N,N,N′,N′-tetrakis(2-pyridylmethyl)ethylenediamine, tppn = N,N,N′,N′-tetrakis(2-pyridylmethyl)propylenediamine ((R)- and (R,S)-forms have been used); M = Mo, W), have been prepared. X-Ray structural analysis (except for the W–tppn complex) revealed ‘basket type’ structures similar to those of the edta and pdta analogs, [M2O2(μ-O)2(μ-edta-N,N′ or μ-pdta-N,N′)]2− (edta = ethylenediamine-N,N,N′,N′ -tetraacetate(4−); pdta = propylenediamine-N,N,N′,N′-tetraacetate(4−)).

    The metal–metal distances of the Mo–tpen, Mo–tppn, and W–tpen complexes are 2.546(1), 2.541(2), and 2.561(1) Å, respectively. Asymmetric distortion along the Mo–Mo axis of the Mo–R-tppn complex is in the opposite direction to that of the corresponding R-pdta complex. The difference may be related to the longer Mo–N(pyridyl) distance and larger N(pyridyl)–Mo–N(pyridyl) angle of the tppn complex as well as the direction of skew conformation of five membered chelate rings M–N(pyridyl)–C–C–N(amine). Electronic absorption spectral patterns of the new complexes are generally similar to the corresponding edta complexes. Circular dichroism (CD) spectra of the R-tppn complexes in the region >300 nm show a pattern nearly enantiomeric to those of the corresponding R-pdta complexes, indicating that the asymmetric distortion is retained in water and in acetonitrile. Kinetic parameters of the inversion of the pseudo-gauche conformation of diamine moiety in the tpen complexes were evaluated from the temperature dependence of 1H NMR spectra in acetonitrile. ΔH’s are significantly larger and ΔS’s are significantly more positive than those of the edta analogs. The inversion may take place through dissociative bond cleavage of the metal–N(pyridyl) bond. The new dimolybdenum complexes show two reversible one electron reduction processes (at −1.40 and −1.86 V vs. Ag/Ag+) in acetonitrile (0.1 mol dm−3). Electronic absorption spectrum of the Mo2(IV,V) mixed valence state was obtained using spectroelectrochemical techniques.

    (Remark: This summary is partially truncated in the html because it exceeds the limit of the system (4000 characters per note). The complete text is given in the pdf.)
  • Toshihiko Yokoyama, Kentaro Kaneyuki, Hitoshi Sato, Hiroshi Hamamatsu, ...
    原稿種別: Accounts
    専門分野: AI
    1995 年 68 巻 2 号 p. 469-475
    発行日: 1995年
    公開日: 2006/07/05
    ジャーナル 認証あり
    The temperature dependence of the I K-edge extended X-ray absorption fine-structure (EXAFS) spectra of a highly oriented iodine-containing polyvinyl alcohol (I-PVA) film was investigated in order to reveal any local structures around I. It was firstly demonstrated that an analysis of the EXAFS amplitude, which is associated with the Debye–Waller factor (mean square relative displacement) provides information concerning the composition ratio of the dopant species. In the present high-contrast I–PVA film it was found that a significant amount (64%) of isolated I is present, and that the polyiodine species, which contributes to a high polarization property of I–PVA for ultraviolet and visible light, consists of 21% I3 and 15% I5, without containing neutral I2.
  • Teruhisa Komura, Hironobu Sakabayashi, Koshin Takahashi
    原稿種別: Accounts
    専門分野: AI
    1995 年 68 巻 2 号 p. 476-480
    発行日: 1995年
    公開日: 2006/07/05
    ジャーナル 認証あり
    The ac response of polyaniline (PA) film electrodes in 0.5 M H2SO4 was investigated at different applied potentials and film thicknesses. The results of impedance analysis on the basis of the Randles equivalent circuit indicated that the electron exchange between metal and redox sites of the polymer controlled the rate of the charge transfer process at the film electrode. The oxidation of the PA film brought about a decrease in charge transfer resistance at lower potentials than the first half-wave potential of PA. The redox capacitance of the polymer indicated the dependence on the potential and film thickness, which was expected from a finite diffusion model. A large capacitance of the order of 3—30 mF cm−2 in the partially oxidized state is explained in terms of the charge saturation effect associated with the finite thickness. Impedance plots at high frequencies (the kHz range) suggested the occurrence of a hydrogen adsorption reaction in the reduced state. The PA film probably swells with the electrolyte. A counter ion to maintain the electroneutrality of the polymer can go into and out of the film with negligible resistance.
  • Masato Tanigawa, Kiwamu Yamaoka
    原稿種別: Accounts
    専門分野: AI
    1995 年 68 巻 2 号 p. 481-492
    発行日: 1995年
    公開日: 2006/07/05
    ジャーナル 認証あり
    The electro-optical and hydrodynamic properties of four synthetic polyribonucleic acids were clarified by electric birefringence methods which take the molecular-weight distribution into consideration. Parallel double-stranded helices, poly(adenylic acid)·poly(protonated adenylic acid), I, and poly(cytidylic acid)·poly(protonated cytidylic acid), II, are known to possess an electric permanent dipole moment, because the reversing-pulse electric birefringence (RPEB) signals of these duplexes exhibit dips upon pulse reversal. The RPEB signals of antiparallel double-stranded poly(adenylic acid)·poly(uridylic acid), III, and poly(guanylic acid)·poly(cytidylic acid), IV, show no dip; therefore, these polynucleotides have no permanent dipole moment. By analyzing the relaxation time of the birefringence decay signals, the axial translations of the polynucleotides per base-pair were determined to be 4.0 Å for I, 2.7 Å for III, and 2.4 Å for IV, respectively. By analyzing the dependence of the steady-state birefringence values on the electric-field strength, the magnitudes of the permanent dipole moments per unit length of I and II projected onto the helix axes were found to be ca. 0.4 debye Å−1. The electric properties unraveled by electric birefringence experiments were compared with calculations based on a recent Manning theory. An unsaturable induced dipole moment may result from the polarization of the Debye–Hückel ion-atmosphere, while a saturable induced dipole moment is probably caused by the polarization of counter ions that are condensed on the charged sites of a polyion. The experimental values deviate from calculated values at ionic strengths lower than 0.0001; hence, the Manning theory is not applicable in this region.
  • Takashi Suzuki, Keiko Iwano, Ryotaro Kiyono, Masayasu Tasaka
    1995 年 68 巻 2 号 p. 493-501
    発行日: 1995年
    公開日: 2006/07/05
    ジャーナル 認証あり
    Solvent transport across hydrocarbonsulfonic acid-type cation-exchange membranes was measured for aqueous electrolyte solutions under a temperature difference and an osmotic pressure difference. The hydrocarbonsulfonic acid-type cation-exchange membranes, Aciplex® K-181, Aciplex® K-182, and Neosepta® C66-5T with the H+, Li+, Na+, K+, NH4+, CH3NH3+, (CH3)2NH2+, (CH3)3NH+, (CH3)4N+, (C2H5)4N+, (n-C3H7)4N+, and (n-C4H9)4N+ forms were used. The direction of thermoosmosis across the membranes with the H+ and the Na+ forms was from the cold side to the hot side, as observed for various anion-exchange membranes. However, the direction was from the hot side to the cold side for the membranes with the ammonium and the alkylated ammonium ion forms, except for Neosepta® C66-5T with the (CH3)4N+, (C2H5)4N+, and (n-C3H7)4N+ forms. This is why the entropy of the water in the membranes will increase with increasing the number of hydrogens combining with the nitrogen of the alkylated ammonium counterions, because they are exchangeable with the hydrogens of water molecules in the membranes. Thermoosmosis across the membranes with the (n-C3H7)4N+ and the (n-C4H9)4N+ forms will also occur toward the cold side, because the hydrophobic interaction between the hydrophobic alkyl groups of the counterions and the membrane matrix is very strong and the membranes act as a hydrophobic polyethylene membrane.
  • Hisao Tanaka, Harumi Saito, Hiroshi Kawazura
    1995 年 68 巻 2 号 p. 502-505
    発行日: 1995年
    公開日: 2006/07/05
    ジャーナル 認証あり
    The spin-relaxation effects of the paramagnetic ions Cu2+ and VO2+ on the protons of solvent water and lipids in phosphatidylcholine unilamellar vesicles were first observed in order to elucidate the details of the interactions in the membrane surface region. VO2+ ions gave higher rates of the effective paramagnetic relaxation induced by binding to a membrane while Cu2+ ions had a larger partition coefficient from water to the membrane phase. It is concluded that VO2+ occupies a binding site closer to the N-methyl groups in the polar-head network and less accessible to a cation, which causes stronger motional restriction to a bound cation, compared with the site occupied by Cu2+.
  • Masayoshi Maehara, Hiroshi Kawano, Yoshinori Nibu, Hiroko Shimada, Ryo ...
    1995 年 68 巻 2 号 p. 506-511
    発行日: 1995年
    公開日: 2006/07/05
    ジャーナル 認証あり
    The effect of pressure on the Raman active inter- and intramolecular vibrations of the pyrazine crystal was studied under hydrostatic pressure up to 5 GPa. The frequency shift of the intermolecular vibrations and the discontinuous variation of the bandwidth of the ν2 and ν1 intramolecular vibrations induced by pressure at constant temperature indicate that the pyrazine crystal undergoes phase transition (change of the molecular orientation in the crystal) under about 1 GPa. The pressure-induced frequency shift of the intramolecular vibrations was calculated using an intermolecular potential of the atom–atom type. The calculation also suggests the occurrence of the phase transition of the crystal.
  • Yasuo Kameda, Ikuko Sugawara, Ken-ichi Kijima, Takeshi Usuki, Osamu Ue ...
    原稿種別: Accounts
    専門分野: AI
    1995 年 68 巻 2 号 p. 512-518
    発行日: 1995年
    公開日: 2006/07/05
    ジャーナル 認証あり
    Polarized Raman spectra of the uncoupled O–D stretching vibrational bands in concentrated aqueous Zn(ClO4)2 solutions have been recorded in the temperature range of 26—95 °C. Observed isotropic and anisotropic spectra have been analyzed by a double-difference method, in conjunction with a least squares fitting procedure, to deduce Raman band components arisen by HDO molecules in the first hydration shell of the constituent ions in the solution. Two band components centered near 2420 and 2640 cm−1 were assigned to the O–D stretching vibrational mode of HDO molecules coordinated to Zn2+ and ClO4, respectively. These frequencies agree with the infrared double-difference results. Further, it has been found that the relative integrated intensity of the ion-perturbed O–D bands is quite different from that of the ‘bulk’ HDO molecules. The temperature dependence of peak parameters such as the frequency and peak area for Zn2+ and ClO4-perturbed bands is very small in the temperature range of 26—95 °C, in contrast to a pronounced collapse of the band from bulk HDO molecules at elevated temperatures. This suggests that the local structure around these ions in the solution changes little in the temperature range examined in this study.
  • Nobuo Tajima, Takayuki Tanaka, Tomoko Arikawa, Takashi Sakurai, Shoich ...
    原稿種別: Accounts
    専門分野: AI
    1995 年 68 巻 2 号 p. 519-527
    発行日: 1995年
    公開日: 2006/07/05
    ジャーナル 認証あり
    A general method has been developed to predict the structures of molecular crystals without any constraints on the space symmetry nor on the lattice constants. A constant-pressure molecular dynamics (MD) technique, treating the lattice constants as variables, is employed in the search of candidate structures (“shaking” process). A heuristic MD search is proposed to reduce redundant sampling in the shaking process. The structures of the thus sampled species are further optimized in geometry by the steepest descent method (“quenching” process). This general method was coded in a program named MDCP (Molecular Dynamics for Crystal Packing), and was applied to the prediction of the crystal structures of CO2, benzene, and pyrimidine molecules, as test examples. For CO2 and benzene crystals, the experimentally observed structures were well reproduced through our method. For pyrimidine, however, a slight difficulty was observed under the atom–atom potentials employed here, although near-miss structures were frequently encountered.
  • Kazunaka Endo, Chiaki Inoue, Yasuo Kaneda, Masayuki Aida, Naoya Kobaya ...
    原稿種別: Accounts
    専門分野: AI
    1995 年 68 巻 2 号 p. 528-538
    発行日: 1995年
    公開日: 2006/07/05
    ジャーナル 認証あり
    The HAM/3 method was used to provide a better assignment of the valence X-ray photoelectron spectra of 16 polymers involving nitrogen, oxygen, fluorine, a glucose unit, and a benzene nucleus using the monomer, dimer or trimer model molecules without consideration of the contraction factor of the energy scale. The calculated Al photoelectron spectra were obtained using Gaussian functions of a fixed approximate linewidth, 0.10 Ik and Ik = Ik − WD, where Ik is the vertical ionization potential of each MO and WD is an approximate shift to account for the work function of the sample and other energy (polarization energy and so on) effects. We assumed that WD corresponds to the shift that we must apply before we can compare the calculated spectrum for the single model molecule with the observed spectrum for the solid. The approximate linewidth corresponds to the experimental result that the inner valence spectra are broader. The theoretical spectra showed good agreement with the spectra of the polymers observed between 0—40 eV.
  • Satoru Takahashi, Nobuyuki Nishi
    原稿種別: Accounts
    専門分野: AI
    1995 年 68 巻 2 号 p. 539-546
    発行日: 1995年
    公開日: 2006/07/05
    ジャーナル 認証あり
    Dilute aqueous solutions of seven diols (1,2-ethanediol, 1,2-propanediol, 1,3-propanediol, 1,2-pentanediol, 2,4-pentanediol, 1,4-pentanediol, and 1,5-pentanediol) were examined by mass spectrometric analysis of the clusters isolated through adiabatic expansion of liquid droplets in vacuum. Stability constants of the solute m-mer hydrate clusters κm (m = 1, 2) were estimated by analyzing the obtained mass spectra. All the stability constants for the diols were found to be approximately equal to or less than 1.0, suggesting that the hydrate clusters of the solute species are as strong as or weaker than those of pure water clusters. Stabilities of the diol hydrate clusters are also dependent on the distance between the two OH groups and/or the number of methylene groups between the two OH groups. From the temperature dependence of the population ratio of the diol-hydrate clusters to pure water ones, we evaluated thermochemical values for the elemental association-dissociation processes.
  • Makoto Inokuchi, Hiroyuki Tajima, Akiko Kobayashi, Toshiaki Ohta, Haru ...
    原稿種別: Accounts
    専門分野: AI
    1995 年 68 巻 2 号 p. 547-553
    発行日: 1995年
    公開日: 2006/07/05
    ジャーナル 認証あり
    The electrical and optical properties were studied concerning α-(BETS)2I3 and α-(BEDT-STF)2I3, which are isostructural to α-(BEDT-TTF)2I3. It has been shown that α-(BETS)2I3 and α-(BEDT-STF)2I3 undergo metal-insulator transitions at around 50 and 80 K, respectively, and that their electrical resistivities exhibit temperature dependences resembling that of α-(BEDT-TTF)2I3 under high pressure. The optical reflectance spectra of these salts show a two-dimensional nature of their electronic structures, and analyses of the spectral data show that the transverse inter-molecular interaction increases in the order α–(BEDT–TTF)2I3 < α–(BEDT–STF)2I3 < α–(BETS)2I3.
  • Mannar R. Maurya, Deena C. Antony, Sarada Gopinathan, Changaramponnath ...
    原稿種別: Accounts
    専門分野: AI
    1995 年 68 巻 2 号 p. 554-558
    発行日: 1995年
    公開日: 2006/07/05
    ジャーナル 認証あり
    The flexibly-bridged hexadentate tetraanionic ligands, LH4 [LH4 = Schiff’s bases obtained by the condensation of methylene- or dithio-bis(salicylaldehyde) with S-methyldithiocarbazate and S-benzyldithiocarbazate], react with [MoO2(acac)2] in a 1 : 2 molar ratio in refluxing methanol to give complexes of the type [(MoO2)2L]. These complexes show an intense ν(Mo=O) band at 924—948 cm−1 and a broad but strong band at ca. 850 cm−1 due to weakened ν(Mo=O) as a result of MoO → Mo interactions. An oligomeric structure, in which each Mo(VI) ion achieves a pseudo-octahedral structure via MoO → Mo bridging, has been suggested for these complexes. [(MoO2)2L] reacts with monodentate ligands (D) like pyridine, 4-methylpyridine, and dimethylsulfoxide and forms six-coordinated complexes of the type [(MoO2)2L(D)2] which are monomers. Cyclic voltammetry measurements indicate that these MoVIO2 complexes are resistant to MoIVO reduction.
  • Bhim Bali Prasad, Sonu Sundd
    1995 年 68 巻 2 号 p. 559-565
    発行日: 1995年
    公開日: 2006/07/05
    ジャーナル 認証あり
    An integral N-based cationic polymer, poly[N-xylylene N,N′-dicyclohexylethylenediammonium dibromide], was immobilized through hydrogen bonding on the surface of silica gel. The chelating ligand, 7-iodo-8-hydroxyquinolino 5-sulfonic acid (Ferron), was subsequently attached to the matrix by ion-exchange method; this renders an extremely stable stationary phase, free from leaching complications, under electrostatic (salt) bond interactions. Analytical characteristics of this sorbent were studied. The optimum sorption conditions for Cu2+, Cd2+, Zn2+, Pb2+, Co2+, Ni2+, and Fe3+ under static and dynamic (column) methods were ascertained. The chelator was found to be selective for the retention of Cu2+, Pb2+, and Fe3+ from multi-element mixtures. The relatively fast kinetics of the sorbent with the time required to reach half of the maximum sorption (t1/2 value 2 min) and the percentage attainment of equilibrium in 2 min (P2 min value > 50%) for most of the heavy metals, excluding Ni2+, reveal the suitability of the chelating resin in column operation, especially in single column ion-chromatography. The specific applications of the sorbent in purification of supporting electrolyte/buffers required for voltammetric detection are also explored.
  • Atsushi Shinohara, Tadashi Saito, Kiyoteru Otozai, Hiromu Fujioka, Kat ...
    原稿種別: Accounts
    専門分野: AI
    1995 年 68 巻 2 号 p. 566-573
    発行日: 1995年
    公開日: 2006/07/05
    ジャーナル 認証あり
    Nuclear excitation by electron transition (NEET) was investigated on 197Au. It is expected for 197Au that the deexcitation of the K-shell ionized atoms would be accompanied by the nuclear excitation of the first excited level. Time spectra of 63-keV electrons emerging from a 197Au target after bombardment with 100-keV pulsed electron beam were measured with a specially designed nanosecond stroboscopic electron spectrometer. A decay component with a half-life of 1.9 ns was extracted from the electron time spectrum. The decay was attributed to the internal conversion electrons emitted from the excited 197Au nucleus as a consequence of the NEET process and the NEET probability was deduced to be P = (5.1 ± 3.6) × 10−5. The result was compared with several theoretical estimates.
  • Masahiro Mikuriya, Takanori Kotera, Fumiya Adachi, Makoto Handa, Masay ...
    1995 年 68 巻 2 号 p. 574-580
    発行日: 1995年
    公開日: 2006/07/05
    ジャーナル 認証あり
    Thiolate-bridged complexes of iron(II) with 2-[(2-aminoethyl)amino]ethanethiol (HLa), 2-[(3-aminopropyl)amino]ethanethiol (HLb), and 2-[[2-(2-pyridyl)ethyl]amino]ethanethiol (HLc) — [Fe{Fe(La)2}2](ClO4)2·CH3OH (1), [Fe{Fe(Lb)2}2]Cl2·2CH3OH (2), and [Fe2(Lc)2(NO3)2] (3), respectively — have been synthesized and characterized by elemental analyses, and infrared and electronic spectroscopies as well as magnetic susceptibilities (80—300 K). The crystal structures of all of these complexes have been measured by single-crystal X-ray diffraction. Each of complexes 1 and 2 has a thiolate-bridged trinuclear iron(II) structure showing a linear arrangement of the three iron atoms with a geometry that may be described as Oh-Td-Oh. Complex 3 is a thiolate-bridged dinuclear iron(II) molecule, in which each iron atom is coordinated in a distorted octahedron. The electronic spectroscopic and magnetic properties are discussed in relation to the crystal structures.
  • Nobutoshi Komeda, Hirotaka Nagao, Yoshinori Kushi, Gin-ya Adachi, Masa ...
    原稿種別: Accounts
    専門分野: AI
    1995 年 68 巻 2 号 p. 581-589
    発行日: 1995年
    公開日: 2006/07/05
    ジャーナル 認証あり
    Copper-nitrito and -nitro isomers, [Cu(ONO)(tpa)]PF6 and [Cu(NO2)(tpa)]PF6 (tpa = tris[(2-pyridyl)methyl]amine) were isolated and the molecular structures were determined by X-ray analysis. [Cu(ONO)(tpa)]PF6 (C18H18N5O2PF6Cu) crystallizes in the monoclinic space group P21/a with a = 13.374(2), b = 14.033(2), c = 13.455(2) Å, β = 119.10(1)°, V = 2206.5(6) Å3, and Z = 4. [Cu(NO2)(tpa)]PF6 (C18H18N5O2PF6Cu) crystallizes in the orthorhombic space group I/ba2 with a = 16.718(3), b = 17.554(3), c = 14.785(3) Å, V = 4338(1) Å3, and Z = 8. Those nitrito- and nitro-complexes exist as an equilibrium mixture in solutions. Electrochemical reduction of NO2 in the presence of [Cu(H2O)(tpa)](ClO4)2 at −0.4 V in H2O (pH 7.0) catalytically produced N2O with concomitant evolution of a small amount of NO via the nitro and nitrito adducts.
  • Saeko Satake, Satoshi Tsukahara, Nobuo Suzuki
    1995 年 68 巻 2 号 p. 590-593
    発行日: 1995年
    公開日: 2006/07/05
    ジャーナル 認証あり
    The extraction equilibrium of Mn(II) was clarified in novel synergic extraction systems using 4,4,4-trifluoro-1-(2-thienyl)-1,3-butanedione (Htta) and neutral multidentate ligands, such as 2,2′ : 6′,2″-terpyridine (terpy) and tetraphenyldiphosphane dioxide (tpdpo), into benzene. No oxidation of Mn(II) and large synergic effect were observed both in the Htta–terpy and Htta–tpdpo systems, and quantitative extraction of Mn(II) was done, which was not attained with Htta only. Mn(II) was extracted as Mn(tta)2(terpy) in the Htta–terpy system, where only two nitrogen atoms of terpy would coordinate to Mn. In the Htta–tpdpo system, two species, i.e. Mn(tta)2(tpdpo) and Mn(tta)2(tpdpo)2, formed in the benzene phase, where tpdpo functioned as a unidentate ligand. The adduct formation constants (βs) and the synergic extraction constants (Kex,s) were obtained and compared with those of other related compounds.
  • Akio Urushiyama, Mutsuyoshi Itoh, Thomas Schönherr
    原稿種別: Accounts
    専門分野: AI
    1995 年 68 巻 2 号 p. 594-603
    発行日: 1995年
    公開日: 2006/07/05
    ジャーナル 認証あり
    The polarized single-crystal absorption spectra of [Cr(CN)(NH3)5]Cl(ClO4) were measured for interconfigurational quartet (t2g3 → t2g2eg) and intraconfigurational doublet transitions (t2g3 → t2g3). The band splittings of the spin-allowed transitions, 4A2g4T2g,4T1g, were derived to 600—1000 cm−1 from a Gaussian band deconvolution of the σ and π spectra. At low temperature (77 K), more than 45 sharp bands could be detected in the intercombination band region of the lowest doublets (2Eg, 2T1g), which were completely assigned to the five possible zero-phonon transitions and corresponding vibronic sidebands. The vibrational frequencies due to the electronic ground state were obtained from the infrared spectrum and by measuring the emission lines under resonant excitation, providing us with a sufficient data base for a normal coordinate treatment of the pentaamminecyano cation. The d-energy level scheme is rationalized using the angular overlap model (AOM). Geometric parameters were obtained from an X-ray analysis of the chloride–perchloride salt, which shows a cation of approximately 4mm (C4v) site symmetry, consistent with a linearly coordinated cyano group. The AOM parameters evaluated for the CN- ligand show strong σ-antibonding (eσ = ca. 7500 cm−1) together with unusually larger π-bonding (eπ = ca. −900 cm−1), which both contribute to the extremely high value of the respective ligand field parameter Dq. The large splitting of the lowest doublet state, 2Eg (Oh), has been shown to originate from a low-symmetry effect in the treatment of interelectronic repulsion. The attributed tetragonal orbital expansion parameter (τ = 0.99) was calculated to be similar to values recently obtained for related pentaammineaniono complexes.
  • Yuqi Feng, Hisanori Imura, Kousaburo Ohashi
    原稿種別: Accounts
    専門分野: AI
    1995 年 68 巻 2 号 p. 604-609
    発行日: 1995年
    公開日: 2006/07/05
    ジャーナル 認証あり
    Binuclear oxomolybdenum(V), Mo2O42+, was quantitatively extracted with 0.01 mol dm−3 2-methyl-5-octyloxymethyl-8-quinolinol (HMO8Q) in chloroform at pH 2.3 and isobutyl methyl ketone at pH 1.0—3.9. To elucidate the extraction equilibrium, the effect of the pH as well as the HMO8Q and molybdenum(V) concentration on the distribution ratio of Mo2O42+ was studied. The extracted complex was found to be Mo2O4(MO8Q)2; the extraction constants (Kex) were determined to be 100.15 and 101.57 in benzene and chloroform, respectively. These values were lower than Kex = 103.26 obtained in the Mo2O42+-5-octyloxymethyl-8-quinolinol–chloroform system, suggesting a steric effect of the methyl group at the 2-position. In the presence of trioctylphosphine oxide (TOPO) a great enhancement of molybdenum(V) extraction was found and could be ascribed to the formation of an adduct, Mo2O4(MO8Q)2(TOPO).
  • Takumi Konno, Ken-ichi Okamoto
    原稿種別: Accounts
    専門分野: AI
    1995 年 68 巻 2 号 p. 610-615
    発行日: 1995年
    公開日: 2006/07/05
    ジャーナル 認証あり
    The reaction of fac(S)-[Rh(aet)3] with Ni2+ at room temperature gave a linear-type S-bridged RhIIINiIIRhIII trinuclear complex, [Ni{Rh(aet)3}2]2+ (1). A similar reaction of ΔLLL-fac(S)-[Rh(L-cys-N,S)3]3− with Ni2+ produced the corresponding trinuclear complex with L-cys ligands, ΔLLLΔLLL-[Ni{Rh(L-cys-N,S)3}2]4− (ΔLLLΔLLL-2), retaining the ΔLLL configuration of the starting complex. The crystal structure of 1(NO3)2 was determined by X-ray diffraction. [Ni{Rh(aet)3}2](NO3)2·2H2O, chemical formula C12H40N8S6O8NiRh2, crystallizes in the triclinic space group with a = 12.249(3), b = 13.366(4), c = 10.260(2) Å, α = 108.76(1), β = 102.46(1), γ = 101.21(1)°, V = 1488.7(7) Å3, Z = 2, and R = 0.024. In 1 the central NiII atom is situated in a distorted octahedral geometry, coordinated by six thiolato sulfur atoms from the two octahedral fac(S)-[Rh(aet)3] units. The two fac(S)-[Rh(aet)3] units have the same absolute configuration to form the racemic (ΔΔ/ΛΛ) isomer. The optically active ΔΔ and ΛΛ isomers of 1 were derived from ΔΔΔΔ- and ΛΛΛΛ-[{Rh(aet)3}4Zn3(HO)]5+ respectively, by adding excess Ni2+. The electronic absorption spectral behavior of 1 indicated that the intermolecular exchange of the fac(S)-[Rh(aet)3] units occurs in solution, which results in the formation of the ΔΛ (meso) isomer from a 1 : 1 mixture of the ΔΔ and ΛΛ isomers. The chemical properties of the present RhIIINiIIRhIII complexes are discussed in comparison with those of the corresponding CoIIINiIICoIII and RhIIICoIIIRhIII complexes.
  • Jitsuo Kiji, Tamon Okano, Hitoshi Kitamura, Yasushi Yokoyama, Shuji Ku ...
    原稿種別: Accounts
    専門分野: AI
    1995 年 68 巻 2 号 p. 616-619
    発行日: 1995年
    公開日: 2006/07/05
    ジャーナル 認証あり
    2,6,6-Trimethyl-5-(2,5-dimethyl-3-furyl and -3-thienyl)-3-heptyn-2,5-diols were carbonylated in benzene in the presence of 1 : 1 — Pd(OAc)2/I2 as the catalyst. The reaction at 90 °C under 80 atm of carbon monoxide for 5 h directly gave both E and Z isomers of t-butyl-substituted furyl- or thienyl fulgides. The former had been reported impossible to synthesize by the Stobbe condensation. Similarly, furyl- and thienylfulgides with an isopropyl group were synthesized by this method. The fulgides were isolated by column chromatography in 37—75% yields. Coloring quantum yields of t-butyl-furyl- and -thienylfulgides are 0.79 and 0.73, respectively, which are the greatest in each series of fulgides with the same heteroaromatic ring.
  • Misato Iwatsuki, Erika Komuro, Etsuo Niki
    1995 年 68 巻 2 号 p. 620-624
    発行日: 1995年
    公開日: 2006/07/05
    ジャーナル 認証あり
    The antioxidant activities of 48 kinds of aminophenols, chromanols, indoles, carbazoles, aromatic amines, and related compounds were assessed in the oxidations of methyl linoleate in acetonitrile solution induced by azo radical initiator. Chromanols, aminochroman and p-phenylenediamines exhibited strong antioxidant activity. Indole and carbazole did not act as antioxidant per se, but those having either amino or hydroxy group as substituent at the para position acted as potent antioxidant. Amino-substituted compounds were in general more potent than hydroxy-substituted ones. These results were interpreted by both polar and resonance effect.
  • Kozo Matsumoto, Katsukiyo Miura, Koichiro Oshima, Kiitiro Utimoto
    1995 年 68 巻 2 号 p. 625-634
    発行日: 1995年
    公開日: 2006/07/05
    ジャーナル 認証あり
    1-Allyloxy-2-bromo-1-phenylsilacyclopentane was synthesized by a ring-enlargement reaction of 1-allyloxy-1-phenylsilacyclobutane with LiCHBr2. The treatment of 1-allyloxy-2-bromo-1-phenylsilacyclopentane with n-Bu3SnH in the presence of a catalytic amount of Et3B provided 2-oxa-1-silabicyclo[3.3.0]octane, which was converted into 1,3,6-triol by an oxidative cleavage of silicon–carbon bonds with H2O2. An intermolecular radical addition of 2-iodosilacyclopentane to acetylenic compounds afforded the corresponding iodoalkenes.
  • Masao Hisatome, Jun Watanabe, Koji Yamakawa, Kozo Kozawa, Tokiko Uchid ...
    原稿種別: Accounts
    専門分野: AI
    1995 年 68 巻 2 号 p. 635-644
    発行日: 1995年
    公開日: 2006/07/05
    ジャーナル 認証あり
    A review of synthetic and structural studies of ferrocenophanes has led to the presumption that the intramolecular substitution of ferrocenophanepropionic acid gives a bridged product when “the distance” between the two carbons to be bridged is greater than 3.20 Å. According to this prediction, the bridging reaction of [4][32](1,2,4)ferrocenophane-5-propionic acid (“the distance”: ca. 3.5 Å) was carried out, and the expected bridged compound (13) was afforded. Subsequently, the construction of fourth and fifth bridges in [4][32](1,3,4)ferrocenophane (16) was attempted by applying the working hypothesis in order to obtain perbridged [4][34](1,2,3,4,5)ferrocenophane (5). Both bridging reactions occurred as expected, and the synthesis of 5 was achieved. The absorption spectrum of 5 showed d–d* absorption at an unusually short wavelength (λmax = 345 nm; ferrocene, 443 nm), which is the shortest value in ferrocene derivatives to our knowledge. The structure of 5 was determined by an X-ray diffraction method. Compound 5 crystallizes in a tetragonal system, space group 2d with unit-cell parameters of a = 14.574(4), c = 18.208(4) Å and Z = 8; its R value converged to 0.051 for 1315 reflections. The observed distance between the iron atom and the least-squares aromatic ring of 1.55(9) Å is the smallest among those of all observed multibridged ferrocenophanes. The conformation of the ferrocene moiety is exactly eclipsed, and the dihedral angle of the two rings is small (1.9°).
  • Masahiko Taniguchi, Koichiro Oshima, Kiitiro Utimoto
    1995 年 68 巻 2 号 p. 645-653
    発行日: 1995年
    公開日: 2006/07/05
    ジャーナル 認証あり
    Stereoselective allylation of 2-formyl amides or 3-oxo amides has been studied. Treatment of 2-formyl-N,N-dimethylpropanamide (1a) with allylzinc bromide gave 3-hydroxy-2,N,N-trimethyl-5-pentenamide as a stereoisomeric mixture (2a : 3a = 63 : 37). Meantime, the reaction of 1a with allyltrimethylsilane in the presence of Lewis acid such as EtAlCl2 or BF3·OEt2 afforded threo-adduct 2a exclusively. Whereas treatment of 2-benzoyl-N,N-dimethylpropanamide (PhCOCH(Me)CONMe2) with allylzinc bromide provided erythro-3-hydroxy-2-methyl-3-phenyl-5-hexenamide with high stereoselectivity, allylation with allylsilane in the presence of a catalytic amount of n-Bu4NF afforded stereoisomeric threo hydroxy amide exclusively.
  • Futoshi Kawataka, Isao Shimizu, Akio Yamamoto
    原稿種別: Accounts
    専門分野: AI
    1995 年 68 巻 2 号 p. 654-660
    発行日: 1995年
    公開日: 2006/07/05
    ジャーナル 認証あり
    By removing the bromide ligand in trans-[PdBr(Ph)(PMe3)2] (1) by AgBF4 in the presence and absence of pyridine, pyridine-coordinated and solvent-coordinated cationic complexes, trans-[PdPh(py)(PMe3)2]BF4 (2) and trans-[PdPh(solvent)(PMe3)2]BF4 (3), have been obtained. These cationic phenylpalladium complexes show much greater reactivities than do the parent neutral complex 1 toward olefins to give phenylated olefins by insertion followed by β-hydrogen elimination processes. Kinetic studies concerning the insertion of methyl acrylate into the phenyl-palladium bond have indicated that the reactions are first order in the phenylpalladium complexes and that addition of pyridine to a system containing 2 and methyl acrylate inhibits the insertion reaction of the olefin. The results suggest that the generation of a cationic arylpalladium complex with a vacant site is important for the olefins to be inserted.
  • Hiroyuki Tani
    原稿種別: Accounts
    専門分野: AI
    1995 年 68 巻 2 号 p. 661-669
    発行日: 1995年
    公開日: 2006/07/05
    ジャーナル 認証あり
    1,2 : 5,6-Bis(ethylenedithio)pyracylene (2) was synthesized as an example of molecular design for a polyaromatic condensed-type donor with two ethylenedithio groups at the periphery. The redox potential of 2 indicates that this heterocycle is a reversible two-stage redox system with low oxidation potentials, which enhances the donor ability. This donor was readily oxidized to afford single crystal radical cation salts with hexafluorophosphate (PF6) and triiodide (I3) by electrocrystallization. The crystal structures of the radical cation salts, (2)3(PF6)2 and (2)2I3, show segregated stacks of donors and anions. The I3 salt presents a two-dimensional sheet along the ab plane similar to I3 salt of bis(ethylenedithio)tetrathiafulvalene.
  • Katsuya Matsumoto, Takashi Ebata, Koshi Koseki, Koji Okano, Hiroshi Ka ...
    原稿種別: Accounts
    専門分野: AI
    1995 年 68 巻 2 号 p. 670-672
    発行日: 1995年
    公開日: 2006/07/05
    ジャーナル 認証あり
    Two lactones, (3S,4R)- and (3R,4R)-3-hydroxy-4-hydroxymethyl-4-butanolides, were easily and stereoselectively synthesized in good yield from levoglucosenone (1,6-anhydro-3,4-dideoxy-β-D-glycero-hex-3-enopyranos-2-ulose).
  • Mizue Fujio, Toshihiro Susuki, Mutsuo Goto, Yutaka Tsuji, Ken-ichi Yat ...
    原稿種別: Accounts
    専門分野: AI
    1995 年 68 巻 2 号 p. 673-682
    発行日: 1995年
    公開日: 2006/07/05
    ジャーナル 認証あり
    Solvolysis rates of p-nitrobenzyl and 3,5-bis(trifluoromethyl)benzyl p-toluenesulfonates were determined in a wide variety of solvents. The solvent effects were analyzed based on the Winstein–Grunwald equation. The solvent effect on these deactivated benzyl solvolyses failed to give a single linear correlation with the 2-adamantyl YOTs parameter. The lower response to the solvent polarity and the pattern of dispersion for respective binary solvent series can be interpreted in terms of nucleophilic solvent assistance. The application of the equation gave a low m value of 0.4 and a large l of close to unity for both derivatives. Furthermore, the l value is also comparable to that for ethyl p-toluenesulfonate and even close to that for the methyl derivative, which has generally been defined as the standard SN2 substrate.
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