Bulletin of the Chemical Society of Japan
Online ISSN : 1348-0634
Print ISSN : 0009-2673
ISSN-L : 0009-2673
Volume 77 , Issue 5
Showing 1-24 articles out of 24 articles from the selected issue
Award Accounts
The Chemical Society of Japan Award for 2002
  • Akira Hosomi, Katsukiyo Miura
    2004 Volume 77 Issue 5 Pages 835-851
    Published: 2004
    Released: May 06, 2004
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    Our research works in the last few decades are summarized. We have studied the synthetic use of organometallics, especially organosilicon compounds, and have developed a number of new reagents and reactions useful for efficient organic synthesis. In the first section, the allylation of carbon electrophiles with allylsilanes, the so-called Hosomi–Sakurai reaction, is described. We have demonstrated that the allylation reaction is valuable not only for highly regio- and stereoselective carbon–carbon bond formation but also for introduction of a variety of functionalities. The second section deals with synthetic reactions using highly coordinated organosilanes and other organometallics, including Cr, Mn, Fe, and Cu. Higher coordination by one or more extra anionic ligands brings about unique reactivities that enable synthetically useful transformations. As shown in the third section, we developed stable 1,3-dipole equivalents protected by a silyl group and their cycloadditions, leading to N, S, or O-containing heterocycles. The following section describes the stereoselective synthesis of cyclic ethers and amines by acid-catalyzed cyclizations of vinylsilanes bearing a hydroxy or amino group. These silicon-directed cyclizations have disclosed the synthetic utility of β-silylcarbenium ion species generated from vinylsilanes by protonation. The copper-catalyzed reactions of organosilanes via silicon–copper exchange are described in the fifth section. In the final section, our studies on homolytic carbometalation reactions are presented.
The Chemical Society of Japan Award for Young Chemists for 2002
  • Masayoshi Higuchi, Kimihisa Yamamoto
    2004 Volume 77 Issue 5 Pages 853-874
    Published: 2004
    Released: May 06, 2004
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    Dendritic and cyclic polyphenylazomethines (DPA and CPA) were exploited as π-conjugated polymer ligands having novel topological structures. DPAs were synthesized by the convergent method via dehydration in the presence of TiCl4. DPA G4 molecules have a sphere-like structure with a 2.3-nm diameter, and they are regularly assembled without deformation of the molecule on a plate, as observed by means of GPC, molecular modeling, TEM, AFM, and π–A measurements. The stepwise radial complexation in DPAs with SnCl2 was observed as a stepwise shift in the isosbestic point in the UV–vis spectra; this conclusion was further supported by TEM, NMR, and shell-selective reduction (SSR) of the imines. The order of complexation among the shells permits control by the introduction of electron-withdrawing groups to the DPA structure. CPAn-ab and CPAn-aabb (designated as CPAX-Y where X and Y are the degree of polymerization and whether the polymerization was AB- or AABB-type, respectively) was synthesized via dehydration in the presence of TiCl4, TiCl4(THF)2 or p-toluenesulfonic acid (PTS). The unique structures of CPAn-ab and CPAn-aabb: triangle, square, or oblong, and their regular molecular-packing were revealed by NMR, MD calculations, and X-ray crystal analysis. CPAn-aabb shows reversible redox functions by protic acid doping, unlike conventional polyphenylazomethine (PPA).
  • Ken Ohmori
    2004 Volume 77 Issue 5 Pages 875-885
    Published: 2004
    Released: May 06, 2004
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    A convergent asymmetric synthesis of the antineoplastic marine macrolide, bryostatin 3 (1), has been achieved. This synthesis relied upon stereo-controlled construction of two major fragments, the top-half fragment 2 and the bottom half fragment 3, and their coupling by the Julia–Lythgoe olefination and Yamaguchi macrolactonization. The top-half fragment 2 could successfully be synthesized by tandem connection of the three key fragments. The bottom-half fragment 3 was prepared by the union of vinyl iodide 39 and α-alkoxy aldehyde 30.
Accounts
Theoretical and Physical
  • Koichi Ohno
    2004 Volume 77 Issue 5 Pages 887-908
    Published: 2004
    Released: May 06, 2004
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    This is a brief survey of studies on exterior characteristics of molecules conducted by means of atomic probes, mostly by metastable states of rare gas atoms in collisional ionization experiments and partly by atoms from H to Ar in quantum chemical calculations. Spatial distributions of molecular orbitals (MO) outside the molecular surfaces have been studied to determine stereoelectronic properties related with partial ionization cross sections of molecules due to electrophilic attacks of metastable atoms. A newly developed collision-energy/electron-energy resolved two-dimensional electron spectroscopy has disclosed anisotropic and dynamic characteristics of molecular surfaces (MS) via collision-energy dependence of partial ionization cross sections. Starting from a simple theoretical model of exterior electron densities (EED), researchers have developed quantum chemical treatments of the ionization reactions to a level of trajectory calculations based on potential energy surfaces of both entrance and exit reaction channels together with electronic transition rates between the surfaces. The present stage of techniques can elucidate one of the two aspects, MO or MS, assuming knowledge of the other. Since experimental aspects may contain various features of MO and MS, a simultaneous determination of both MO and MS by experiments will allow further developments in experimental techniques.
Organic and Biological
  • Yasutaka Ishii, Satoshi Sakaguchi
    2004 Volume 77 Issue 5 Pages 909-920
    Published: 2004
    Released: May 06, 2004
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    We have found that the [{IrCl(cod)}2] complex catalyzes several reactions involving three-component couplings, hydrogen migration, vinyl ethers synthesis, and α-alkylation of ketones with alcohols, etc. Thus, the reaction of aldehydes, amines, and alkynes under the influence of a catalytic amount of [{IrCl(cod)}2] complex led to three-component coupling products through a new type of C–H bond activation adjacent to the nitrogen atom of imines. Aziridines were also synthesized by three-component couplings of aldehydes, amines, and ethyl diazoacetate in the presence of a catalytic amount of [{IrCl(cod)}2]. An innovation in the synthesis of vinyl ethers, which are very useful monomer materials in polymer syntheses but have been difficult to synthesize so far, was made by a simple exchange reaction of alcohols with vinyl acetates through a catalytic process using [{IrCl(cod)}2]. A unique α-alkylation of ketones with alcohols was successfully achieved under the influence of [{IrCl(cod)}2] and KOH without any solvents, leading to saturated ketones that elongated the carbon chain. Allyl homoallyl and diallyl ethers were converted by [{IrCl(cod)}2] into γ,δ-unsaturated aldehydes via a Claisen rearrangement of in situ-generated allyl vinyl ethers. These reactions provide a novel synthetic tool for important chemicals like vinyl ethers and ketones, which are practically synthesized in the chemical industry.
Headline Articles
Theoretical and Physical
  • Tadahiro Nakamoto, Ashis Bhattacharjee, Michio Sorai
    2004 Volume 77 Issue 5 Pages 921-932
    Published: 2004
    Released: May 06, 2004
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    Thermodynamic properties of an iron(II) spin crossover complex [Fe(2-pic)3]Cl2·H2O (2-pic: 2-picolylamine or 2-aminomethylpyridine), for which an unusually large thermal hysteresis with a width of [Tc(↑) − Tc(↓) = 91 K] in its spin-state transition has been observed by 57Fe Mössbauer spectroscopy, were investigated by adiabatic heat capacity calorimetry. Contrary to the previous observation, the preliminary DTA result showed much smaller thermal hysteresis around 200 K, with a width of [Tc(↑) − Tc(↓) = 12 K]. The present heat capacity measurement by adiabatic calorimetry revealed that there exists a metastable low-spin low-temperature phase, besides the stable low-spin low-temperature phase and that this complex undergoes stabilization from the metastable low-spin phase to the stable low-spin phase accompanied by a large heat evolution when the sample is annealed around 200 K. The stable low-spin phase exhibited a phase transition to the high-spin high-temperature phase around 280 K upon heating. The high-spin state was found to be always undercooled down to ∼200 K. The large thermal hysteresis earlier reported for the title complex turns out to be apparent and is caused by the existence of the metastable low-spin phase. Moreover, another intermediate metastable (low-spin?) phase was found when the sample in the metastable low-spin phase was heated from 150 K at a heating rate of ∼5 K h−1. This metastable phase exhibited a phase transition to the undercooled high-spin phase at ∼265 K.
Articles
Theoretical and Physical
  • Nobuhiro Yasuda, Hidehiro Uekusa, Yuji Ohashi
    2004 Volume 77 Issue 5 Pages 933-944
    Published: 2004
    Released: May 06, 2004
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    The photo-excited structures of [Pt2(pop)4]4− and [Pt2(pop)2(popH)2]2−, (pop = diphosphite) in five kinds of complexes were analyzed by X-rays. For the complex with tetrabutylammonium (Bu), tetrapentylammonium (Pn), benzyltriethylammonium (Bzte), or benzyltributylammonium (Bztbu) as a counter cation, the Pt complex anion is attached by two protons and is represented as [Pt2(pop)2(popH)2]2−, whereas the anion is [Pt2(pop)4]4− for the complex with benzyldimethylphenylammonium (Bzdmp) as a cation. Since the Bu, Pn, and Bzte complexes have two crystal forms, the structures of eight crystals, Bu1, Bu2, Pn1, Pn2, Bzte1, Bzte2, Bztbu, and Bzdmp, were determined by X-ray analysis before irradiation. The five crystals of Bu1, Pn1, Bzte1, Bztbu, and Bzdmp were irradiated with a xenon lamp. The intensity data were collected at the light-on and light-off stages at 173 K for Bu1, Pn1, and Bzdmp crystals and at 103 K for Bzte1 and Bztbu crystals. Each crystal showed the contraction of the unit-cell volume significantly at light-on stage and returns to the original one at light-off stage. The analyzed structures at light-on and light-off stages clearly indicated that the Pt–Pt and Pt–P bond distances became significantly shorter at light-on stage than the corresponding distances at light-off stage. The decreased values for the Pt–Pt and Pt–P distances at the light-on stage are 0.0038(3) and 0.0069(10) Å for Bu1, 0.0081(3) and 0.0053(11) Å for Pn1, 0.0127(5) and 0.0085(14) Å for Bzte1, 0.0031(3) and 0.0019(12) Å for Bztbu, and 0.0019(2) and 0.0033(8) Å for Bzdmp, respectively. The other bond distances in anions and cations are not significantly changed. These structural changes indicate that the excited- and ground-state molecules reach the equilibrium state at the light-on stage; the values are in good agreement with the results observed by spectroscopic methods and theoretical calculation.
  • Seiya Kobatake, Shunpei Kuma, Masahiro Irie
    2004 Volume 77 Issue 5 Pages 945-951
    Published: 2004
    Released: May 06, 2004
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    A fluorene derivative having two diarylethene units at the 9,9′-positions was synthesized, and the photochromic behavior was examined in a single-crystalline phase as well as in solution. Upon irradiation with ultraviolet light (λ = 313 nm), a hexane solution of the diarylethene dimer (1a) turned blue. The blue solution was found to contain the one closed-ring form dimer (1b) and the two closed-ring form dimer (1c). Both 1b and 1c returned to 1a upon irradiation with visible light (λ > 500 nm). The photocyclization quantum yields of 1a to 1b and 1b to 1c were determined to be 0.46 and 0.29, respectively. The photocycloreversion quantum yields of 1c to 1b and 1b to 1a were 5.8 × 10−3. The single crystal of the dimer exhibited photochromism. The diarylethene chromophores were aligned almost perpendicular to each other in the crystal, and one of the units in the dimer could be selectively isomerized by irradiation with linearly polarized light.
Analytical and Inorganic
  • Munetaka Oyama, Jun Matsui
    2004 Volume 77 Issue 5 Pages 953-957
    Published: 2004
    Released: May 06, 2004
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    The dimerization reaction processes of the 9-phenylcarbazole cation radical (PCZ•+) in acetonitrile (AN) were observed using an electron-transfer stopped-flow method. Although the lifetime of PCZ•+ in AN is less than a few hundred milliseconds, the dynamic transformation of the absorption spectra of PCZ•+ was successfully observed in AN for the first time with the proposed method. By observing the changes in the absorption spectra in the visible region, the decrease in PCZ•+ and the concurrent increase in the dimer cation radical were observed with isosbestic points. In addition, in the presence of neutral PCZ, the acceleration of the dimerization of PCZ•+ was clearly confirmed. Consequently, in the presence of PCZ, the rate law was determined to be −d[PCZ•+]/dt = 3Kk′[PCZ•+]2[PCZ], where 3Kk′ is 1.4 × 109 M−2 s−1. This means that the reaction mechanism involves a two-step interaction with the catalytic effect of neutral PCZ. Although the difference in the reactivity had already been known between PCZ•+ and the triphenylamine cation radical, the reaction mechanism has been clarified to be different in both cases.
  • Chirantan Roy Choudhury, Subrata Kumar Dey, Samiran Mitra, Nijhuma Mon ...
    2004 Volume 77 Issue 5 Pages 959-964
    Published: 2004
    Released: May 06, 2004
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    One novel racemic Cu–Co cyano-bridged complex [C38H38CoCu2N14O]+[C22H18CoCuN10]·7H2O where [L = N,N′-bis(2-pyridylmethylene)butane-1,4-diamine] has been prepared and characterized by elemental analyses, spectroscopic study, single crystal X-ray crystallography, and variable temperature magnetic susceptibility measurements. The compound crystallises as a 57/43 racemic twin and contains two different, one binuclear and one trinuclear, complex species. A low temperature magnetic susceptibility measurement showed the existence of very weak antiferromagnetic interactions.
  • Shigenobu Mitsuzawa, Tetsuyuki Yukawa
    2004 Volume 77 Issue 5 Pages 965-973
    Published: 2004
    Released: May 06, 2004
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    It has been hypothesized that chemical evolution leading to the origin of life might have occurred in hydrothermal environments on primitive Earth. To examine this hypothesis, we investigated how the polymerization of amino acids proceeds under high-temperature and high-pressure conditions. We investigated a reaction network consisting of glycine and oligoglycines up to trimer, and the condensation/hydrolysis reactions among these molecules. We determined the rate constants of these reactions in experiments employing a flow reactor at 200 °C and 25 MPa. We found that two condensation reactions of glycine, which yield diglycine and diketopiperazine as products, have larger equilibrium constants under these conditions than at 25 °C. This result supports the hypothesis that hydrothermal conditions are thermodynamically favorable for chemical evolution. We also found that triglycine formation is mediated by diketopiperazine at 200 °C and 25 MPa. This implies that diketopiperazine acts as an important intermediate in the polymerization process of amino acids, which might have occurred in hydrothermal environments on primitive Earth.
  • Masakazu Moro’oka, Hiroshi Ohki, Koji Yamada, Tsutomu Okuda
    2004 Volume 77 Issue 5 Pages 975-980
    Published: 2004
    Released: May 06, 2004
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    New Ag+ ionic conductors AgHgSX (X = Br, I) were synthesized by solid-state reactions of AgX (X = Br, I) and HgS. AgHgSI shows a phase transition at 578 K. The crystal structure of the high temperature phase has been determined to be P212121 (No. 19) by the Rietveld refinement using the powder X-ray diffraction pattern. The electric conductivity at 500 K measured by the AC impedance method was 2.6 × 10−4 S cm−1 for the high temperature phase of AgHgSI, 1.2 × 10−4 S cm−1 for the low temperature phase of AgHgSI, and 1.1 × 10−4 S cm−1 for AgHgSBr. The charge density analysis of the AgHgSX (X = Br, I) clearly showed the Ag+ ionic conduction path when analyzed by the Maximum Entropy Method (MEM) combined with Rietveld analysis.
  • Eriko Ueda, Yutaka Yoshikawa, Noriko Kishimoto, Makoto Tadokoro, Hirom ...
    2004 Volume 77 Issue 5 Pages 981-986
    Published: 2004
    Released: May 06, 2004
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    Four Zn(II) complexes with dipeptides and three new Zn(II) complexes with pseudo-tripeptides were prepared and a complex, [Zn(glythr)2]n, was revealed to have a polymeric structure by X-ray structure analysis. The ligand, glythr, acts as a bridging ligand completely, a monodentate oxygen atom of the terminal carboxyl group of threonine residue and a didentate ligand containing the nitrogen and oxygen atoms of glycine one. Because the Zn2+ ion has a distorted six-coordinated octahedral geometry, it binds with two terminal carboxyl groups and two didentate ligands. Also, all Zn(II) complexes were found to have high in vitro insulinomimetic activity compared with that of zinc sulfate, as estimated by the inhibition of free fatty acid release in isolated rat adipocytes that had been treated with epinephrine (adrenalin).
  • Masafumi Goto, Yasuhiko Ohse, Sayuri Koga, Yuka Kudo, Rinko Kukihara, ...
    2004 Volume 77 Issue 5 Pages 987-991
    Published: 2004
    Released: May 06, 2004
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    The oxidation of tetracyano(N-benzyl-1,2-ethanediamine) with one equivalent oxidant, hydrogen peroxide or peroxodisulfate, under neutral or basic conditions yielded tetracyano(2-benzylimino-ethylamine)ferrate(II), owing to an acceleration of disproportionation by the presence of N-benzyl substituents. Further oxidation yielded the corresponding conjugated 1,2-diimineferrate(II) complex.
Organic and Biological
Applied and Materials
  • Yoshihiro Nemoto, Takayuki Hirai
    2004 Volume 77 Issue 5 Pages 1033-1036
    Published: 2004
    Released: May 06, 2004
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    A photocatalyst can be used for various applications. Such materials are semiconductors which are stable to photoirradiation, for example, TiO2. Most of these materials require UV light. There are many kinds of semiconductors which are unstable to photoirradiation, but which have a visible light response. In this study, it is shown that a thin Au film or Au nano particles on the surface of the photocatalyst reduced the photodecomposition of the photocatalyst. Although the surfaces of the samples were completely covered by Au, photocatalytic activity was observed in all the Au-coated samples. The Au-coating on the surface enhances the photocatalysis of a coated photocatalyst.
  • Setsuko Irie, Myeong-Suk Kim, Tsuyoshi Kawai, Masahiro Irie
    2004 Volume 77 Issue 5 Pages 1037-1040
    Published: 2004
    Released: May 06, 2004
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    The radiation-induced coloration of bulk amorphous films of five photochromic diarylethenes was studied with the aim of developing reusable, sensitive color dosimeters. The films contain an extremely high concentration of diarylethenes. The most intense coloration was observed for the film containing 1,2-bis(2,4-dimethyl-3-thienyl)perfluorocyclopentene having 3-phenyl-4-diphenylyl substituents. The color disappeared upon irradiation with visible light. The coloration increased linearly with an increase in the absorbed dose up to 3000 Gy. The relative sensitivity of radiation-induced coloration among the five derivatives qualitatively agreed with the sensitivity of photo-induced coloration from UV light (254 nm) irradiation.
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