Bulletin of the Chemical Society of Japan
Online ISSN : 1348-0634
Print ISSN : 0009-2673
ISSN-L : 0009-2673
Volume 71 , Issue 11
Showing 1-31 articles out of 31 articles from the selected issue
  • Koji Otsuka, Shigeru Terabe
    1998 Volume 71 Issue 11 Pages 2465-2481
    Published: 1998
    Released: June 05, 2006
    JOURNALS RESTRICTED ACCESS
    A review of the research on micellar electrokinetic chromatography (MEKC), carried out mainly in our laboratory, is described from the viewpoints of (1) fundamental characteristics of MEKC, such as the separation principle, chromatographic parameters, selectivity and resolution, thermodynamic parameters, retention index, and band broadening; (2) selectivity manipulation, including effects of surfactants, temperature, pH, and various additives; (3) on-line coupling of MEKC with mass spectrometry; (4) applications, such as the separation of closely related compounds and enantiomer separations; and (5) on-line neutral sample concentration techniques.
  • Masamitsu Shirai, Masahiro Tsunooka
    1998 Volume 71 Issue 11 Pages 2483-2507
    Published: 1998
    Released: June 05, 2006
    JOURNALS RESTRICTED ACCESS
    This article describes the recent progress in the preparation of a set of compounds which can generate acids or bases upon irradiation of light. These compounds are called photoacid generators and photobase generators, respectively. Photoacid generators can be divided into two groups according to their characteristics; i.e., ionic- and non-ionic compounds. Photobase generators are fewer than photoacid generators. These compounds are widely used in the field of polymeric photosensitive systems such as photoinitiated polymerization, photoinduced crosslinking of polymers and oligomers, photoinduced degradation of polymers, and photoinduced transformation of functional groups in polymer chains. In particular, this article focuses on the applications of photoacid and photobase generators to promote the development of photoresist and UV curing materials.
  • Takehiko Mori
    Type: Accounts
    Subject area: AI
    1998 Volume 71 Issue 11 Pages 2509-2526
    Published: 1998
    Released: June 05, 2006
    JOURNALS RESTRICTED ACCESS
    A method is proposed to systematize a number of structural modifications of BEDT-TTF (bis(ethylenedithio)tetrathiafulvalene)-based organic conductors and related materials. Analysis of actual crystal structures indicates that most crystal structures are constructed of two essential building blocks: “ring-over-bond” (RB) and “ring-over-atom” (RA) overlap modes. Several different ways to pile up these elements lead to various structures which are conventionally designated as β,β′,β″,θ,α, and α″-phases. In the β- and β″-phases, introduction of “dislocations” along the stacking axis generates a number of modifications. Here dislocations mean interactions of two donor molecules which have larger displacements along the molecular long axis than the standard RB and RA modes. Systematic nomenclature to distinguish these modifications is proposed. Transfer integrals are, however, not very sensitive to the existence of dislocations, so that the Fermi surfaces of these multiple phases are derived from the fundamental structure by folding the first Brillouin zone.
  • Taro Yamada, Yuji Ohashi
    1998 Volume 71 Issue 11 Pages 2527-2537
    Published: 1998
    Released: June 05, 2006
    JOURNALS RESTRICTED ACCESS
    The but-3-en-1-yl group bonded to the cobalt atom in some cobaloxime complexes is isomerized to the but-2-en-1-yl group in the solid state on exposure to a xenon lamp. In order to make clear the relationship between the reaction rate and the crystal structure, six complexes with different axial base ligands were prepared; piperidine, 1, 1-vinylimidazole, 2, pyrrolidine, 3, 1-methylimidazole, 4, 4-t-butylpyridine, 5, and triphenylphosphine, 6. The crystal structures were determined by X-ray analyses and the reaction rates were estimated from the change of the 1H NMR spectra observed in several intermediate stages. One of the photo products, which has 1-vinylimidazole as an axial base ligand, 7, was prepared separately and its crystal structure was also analyzed. A pair of the but-3-en-1-yl groups are in contact with each other around an inversion center in the crystal structures of 2, 5, and 6, whereas the but- 3-en-1-yl groups in 1, 3, and 4 are isolated from the other but-3-en-1-yl groups of the neighboring molecules in their crystal structures. The reaction rates of the former complexes are significantly greater than those of the latter complexes, except 2. This suggests that the cooperative motion of the but-3-en-1-yl groups plays an important role in the process of the isomerization. A pair of the but-3-en-1-yl groups around an inversion center in 2 are too closely packed for the isomerization to occur even if the cooperative motion is taken into account.
  • Yoshiki Tanaka, Masahiro Kawasaki, Yutaka Matsumi
    Type: Accounts
    Subject area: AI
    1998 Volume 71 Issue 11 Pages 2539-2545
    Published: 1998
    Released: June 05, 2006
    JOURNALS RESTRICTED ACCESS
    Photofragment iodine atoms and methyl radicals from the photodissociation of small clusters of methyl iodide at 266 nm were detected, using ion photofragment imaging spectroscopy. Three different components of the I+ image were observed with average laboratory translational energies of the I fragments, <E(I)> = 2, 16, and 25 kcal mol−1 and anisotropy parameters, β = 0, 2.0 ± 0.6, and 2.1 ± 0.5, respectively. Similarly, for CH3+three different components in the CH3+ image correspond to average laboratory translational energies, <E(CH3)> = 5, 25, and 38 kcal mol−1 and β = 0, 2.0 ± 0.2, and 2.2 ± 0.6, respectively. These results suggest the following reaction mechanisms; a) a CH3I chromophore in small clusters is excited to the A band (n,σ*) system of free CH3I, survives intact within the clusters and dissociates, b) dissociation of the CH3I moiety in the small clusters that have two adjacent iodine atoms results in the formation of slow photofragment iodine atoms and fast methyl radicals, and c) dissociation of other types of small clusters results in the formation of fast iodine atoms and slow methyl radicals.
  • Yoshiteru Itagaki, Masaru Shiotani, Akinori Hasegawa, Hisao Kawazoe
    1998 Volume 71 Issue 11 Pages 2547-2554
    Published: 1998
    Released: June 05, 2006
    JOURNALS RESTRICTED ACCESS
    EPR spectra for the radical cations of a series of fluorinated ethylenes and propenes, generated by irradiation with γ-rays in halocarbon solid matrices, have been observed at low temperature. The spectra consist of a hyperfine structure with a nearly axial symmetry mainly due to fluorine nuclei. For the trifluoro olefin cations, CF2=CFX+ (X = H, CH3, or CF3), the experimental spectra were successfully analyzed in terms of the three 19F nuclei with coaxial parallel components. This may strongly suggest a planar structure for the radical cations, similarly to the case of the CF2=CF2+ cation already reported. On the other hand, for mono- and di-fluoro olefin radical cations, it is difficult to conclude the planar structure unequivocally from the experimental 19F and 1H hf splittings. Thus, the optimized geometry of the radical cations was calculated by an ab initio MO method. In contrast with the ethylene cation and the propene cation, having nonplanar twisted structures, the fluorinated ethylene and propene cations are concluded to have planar structures. Calculations at the INDO levels including the evaluation of interatomic dipole-dipole interactions were done for the geometries of the radical cations optimized by the ab initio method. The calculated results strongly support the EPR spectra observed and assigned to the radical cations.
  • Masatoshi Yanagida, Toshihito Kanai, Xue-Qun Zhang, Toshihiro Kondo, K ...
    1998 Volume 71 Issue 11 Pages 2555-2559
    Published: 1998
    Released: June 05, 2006
    JOURNALS RESTRICTED ACCESS
    The orientation of a self-assembled monolayer (SAM) of the 5-(4-{8-[(11-mercaptoundecanoyl)ferrocenyl]octyloxy}phenyl)-10,15,20-triphenylporphyrin (PC8FcC11SH) molecule on a gold substrate, at which a photoinduced up-hill electron transfer with the highest quantum efficiency (>10%) ever reported was achieved, was investigated using angle-resolved X-ray photoelectron spectroscopy (ARXPS) combined with an electrochemical coverage determination. The total thickness and the distance between the Fe and the outermost part of the SAM of the PC8FcC11SH molecule was determined to be 44 and 29 Å, respectively, showing that while alkyl chains in the ferrocenecarbonylundecanethiol (FcC11SH) part of the PC8FcC11SH SAM should be oriented with a tilt angle of ca. 30° normal to the gold surface, the plane of the porphyrin ring should be almost surface-normal. This result suggests that one of the most important reasons for the very high photoconversion efficiency is the large separation between gold and the porphyrin ring, leading to a reduction in the reverse electron transfer and energy transfer quenching of the excited porphyrin state by gold.
  • Masashi Tanaka, Takayuki Imai, Takehiko Goto, Jun-ichiro Taka, Mitsuhi ...
    Type: Accounts
    Subject area: AI
    1998 Volume 71 Issue 11 Pages 2561-2571
    Published: 1998
    Released: June 05, 2006
    JOURNALS RESTRICTED ACCESS
    N-Salicylidene-2-aminopyridine (NSAP) and 1,3,5-trinitrobenzene (TNB) form two kind of crystalline (1/2) complexes, forms I and II. The thermochromism was observed in a charge transfer complex form I, but not in form II. The thermochromism of these crystals was studied based on the temperature dependence of the X-ray analysis and the IR and visible absorption spectra together with the theoretical analysis.
  • Yasuchika Hasegawa, Mitsunori Iwamuro, Kei Murakoshi, Yuji Wada, Ryuic ...
    Type: Accounts
    Subject area: AI
    1998 Volume 71 Issue 11 Pages 2573-2581
    Published: 1998
    Released: June 05, 2006
    JOURNALS RESTRICTED ACCESS
    Coordination structures of neodymium(III) complexes with some β-diketones were investigated in terms of their correlations with emission efficiency in deuterated dimethylsulfoxide (DMSO-d6). The analysis of UV-vis spectra, 13C NMR, electrospray mass spectrometry (ES-MS) spectra, XANES and EXAFS analysis of tris(hexafluoroacetylacetonato)neodymium(III) complex, [Nd(hfa-H)3(H2O)2], and tris[bis(perfluorooctanoyl)methanato]neodymium(III), [Nd(pom-H)3], in DMSO indicated that the deuterated tris(hexafluoroacetylacetonato)neodymium(III), Nd(hfa-D)3, and deuterated tris[bis(perfluorooctanoyl)methanato]neodymium(III), Nd(pom-D)3, in DMSO-d6 should have a symmetrical, rigid and bulky shell composed of six inner-coordinating DMSO molecules and three weakly coordinating hfa-D and pom-D molecules. The improvement in the emission efficiency of the neodymium complexes with the low vibrational and weakly coordinating β-diketonates in DMSO-d6 was ascribed to their symmetrical rigid coordination structures, which should suppress radiationless transition via vibrational excitation and energy migration in the fluid system.
  • Takayuki Ishida, Kensuke Togashi, Ron Imachi, Hajime Yamamoto, Masanor ...
    Type: Accounts
    Subject area: AI
    1998 Volume 71 Issue 11 Pages 2583-2587
    Published: 1998
    Released: June 05, 2006
    JOURNALS RESTRICTED ACCESS
    Temperature dependences of d.c. magnetic susceptibilities and magnetizations were measured for two different crystallographic phases of 4-(4-iodobenzylideneamino)-2,2,6,6-tetramethylpiperidin-1-yloxyl. Intermolecular ferromagnetic (Weiss temperature θ = +0.71 K) and antiferromagnetic (θ = −0.23 K) interactions were found for α- and β-phases, respectively, in the magnetic measurements above 1.8 K; the former phase showed a bulk ferromagnetic transition at 0.28 K. Based on the X-ray crystallographic data, intermolecular magnetic interactions are discussed. In the α-phase crystal, NO-radical sites form two-dimensional zigzag sheets. The ferromagnetic interaction within the sheet can be interpreted in terms of a β-hydrogen mechanism, ON(↑)–Cα(↓)–Cβ(↑)–Hβ(↓)···(↑)ON<, in which the magnetic interaction is transmitted by β-hydrogens. A dimer structure was found in the β-phase crystal, and direct exchange and/or dipole interactions between N–O radicals seem to be the main origin of the antiferromagnetic interaction.
  • Terumasa Yata, Kazuo Nomura
    Type: Accounts
    Subject area: AI
    1998 Volume 71 Issue 11 Pages 2589-2595
    Published: 1998
    Released: June 05, 2006
    JOURNALS RESTRICTED ACCESS
    Transient and steady membrane potentials in response to a bitter substance have been measured in a membrane filter impregnated with phospholipid and 1-octanol. Quinine, which is one of the alkaloids, was used as the bitter substance. The internal and external solutions both contained 0.1 mol dm−3 KCl. A cation exchange liquid membrane was formed in a Teflon filter by impregnating it with a 1-octanol solution of dihexadecyl hydrogenphosphate (DCP). After the injection of the solution of quinine hydrochloride into the external solution, the membrane potential rapidly increased to reach a peak and gradually decreased to relax to a level of another steady potential. The time course curve of membrane potential was resolved in the early portion and the other portion after the peak to obtain the Donnan potential at the interface and the diffusion potential within the membrane at steady state, respectively. In comparison with the case of the response to HCl, even a small amount of aqueous quinine hydrochloride induced a great magnitude of change both in the Donnan potential and in the diffusion potential within the membrane. The amount of quinine transported across the membrane was measured by UV spectrophotometry. From the time dependence of the UV spectrum, we determined the time lag for the membrane diffusion to obtain the diffusion coefficient of quinine in the membrane. According to the theoretical expressions of the Donnan potential at the interface for the charged membrane and the intramembrane diffusion potential derived by solving the Nernst–Planck equations taking into account the Donnan equilibrium at the interface, these two constituents of the total membrane potential were estimated using the diffusion coefficient. By fitting the theoretical curves to the experimental results, large values of the partition coefficient and the equilibrium constant of the complex formation with DCP for monoprotonated quinine ion relative to potassium ion were obtained.
  • Hitoshi Kasai, Hidetoshi Oikawa, Shuji Okada, Hachiro Nakanishi
    Type: Accounts
    Subject area: AI
    1998 Volume 71 Issue 11 Pages 2597-2601
    Published: 1998
    Released: June 05, 2006
    JOURNALS RESTRICTED ACCESS
    The crystal growth of α-perylene microcrystals in the reprecipitation method was studied using of light-scattering technique and absorption spectroscopy. A certain model for microcrystallization has been established. The relationship between the reprecipitation conditions and the crystal size was clarified on the basis of this model. Especially, the water temperature was confirmed to be one of the most important parameters used to control the size of the microcrystals in the reprecipitation method. The apparent activation energy for the microcrystallization of perylene was estimated to be 68 kJ mol−1.
  • Kenji Nomiya, Katsunori Ohsawa, Takayuki Taguchi, Masahiko Kaneko, Tos ...
    Type: Accounts
    Subject area: AI
    1998 Volume 71 Issue 11 Pages 2603-2610
    Published: 1998
    Released: June 05, 2006
    JOURNALS RESTRICTED ACCESS
    The Keggin-type triniobium(V)-substituted tungstoheteropolyanion, A-β-SiW9Nb3O407−, was synthesized as its hepta alkali-metal salts of Li+, Na+, K+, and Cs+countercations. These alkali-metal salts were useful for allowing the crystallization of SiW9Nb3O407−, itself, and/or the SiW9Nb3O407−-supported organometallic complexes, as well as controlling the water solubility of these complexes. The analytically pure compounds, obtained as homogeneous colorless solids via a stoichiometric reaction of the (Bu4N)6H2Si2W18Nb6O77, (Nb–O–Nb)3-bridged anhydride with the corresponding alkali tetrafluoroborates, and then with the alkali hydroxides, were compositionally characterized by complete elemental analyses, TG/DTA and FABMS spectra. They were structurally characterized by FT-IR and solution 183W NMR measurements, as well as solid-state CP/MAS and GHD/MAS 29Si NMR and solution 29Si NMR measurements. The cation-dependent properties of these heteropolytungstates in the solid state were observed in the thermal stabilities, the amounts of hydrated water and adsorbed water, the solubilities in water and in organic solvents, and in the ease of crystallization.
  • Yukinari Sunatsuki, Toshihiro Matsuo, Masaaki Nakamura, Fumiaki Kai, N ...
    Type: Accounts
    Subject area: AI
    1998 Volume 71 Issue 11 Pages 2611-2619
    Published: 1998
    Released: June 05, 2006
    JOURNALS RESTRICTED ACCESS
    Dipotassium N,N′-1,2-phenylenebis(2-carbamoyl-κN-phenolato-κO]cuprate(II)), K2[CuL], reacts with nickel(II), cobalt(II), and zinc(II) acetates, and 2,2′-bipyridine in a 1 : 1 : 2 molar ratio in methanol to yield the hetero-metal dinuclear complexes [CuLNi(bpy)2]·3MeOH (1·3MeOH), [CuLCo(bpy)2]·2DMF (2·2DMF), and [CuLZn(bpy)2]·1.5H2O (3), respectively. Crystal data for 1 : P1 (No. 2) with a = 15.969(2), b = 23.494(3), c = 12.705(2) Å, α = 92.15(1), β = 91.652(10), γ = 101.521(9)°, V = 4663(1) Å3, and Z = 4; 2, P21/c (No. 14) with a = 12.604(3), b = 24.364(5), c = 13.823(2) Å, β = 94.49(1)°, V = 4231(1) Å3, and Z = 4. 1 and 2 have a similar discrete di-μ-phenoxo-bridged dinuclear structure, in which the Cu(II) ion assumes a square-planar geometry with the N2O2 donors atoms consisting of two amido nitrogen and two phenoxo oxygen atoms of the tetradentate ligand, and the Ni(II) or Co(II) ion assumes an octahedral geometry with the two phenoxo oxygens of the tetradentate ligand and four nitrogen atoms from two bpy. The magnetic-susceptibility data were reproduced based on the isotropic spin Hamiltonian H = −2JS1·S2 with J = −118.0 cm−1, (S1, S2) = (1/2, 1) for 1 and J = −11.0 cm−1, (S1, S2) = (1/2, 3/2) for 2, respectively. When 3 was recrystallized from DMF/2-propanol, [CuLZn(bpy)]2·2DMF (3′) was obtained. The 1 : 1 : 1 reaction of K2[CuL′], copper(II) acetate monohydrate, and 2,2′-bipyridine in methanol yielded [CuL′Cu(bpy)]2·2MeOH (4), (H4L′ = 1,2-bis(hydroxybenzamido)ethane). Crystal data for 3′: Pbca (No. 61) with a = 19.143(2), b = 18.195(2), c = 16.832(3) Å, and Z = 4; 4, P21/n (No. 14) with a = 13.407(1), b = 13.172(4), c = 13.764(2) Å, β = 94.11(1)°, V = 2424.4(8) Å3, and Z = 4. 3′ and 4 have a similar cyclic di-μ-phenoxo-μ-amido-bridged tetranuclear structure, which can be described as two di-μ-phenoxo-bridged dinuclear units bridged together by the coordination of one amido oxygen atom from each dinuclear unit to the zinc(II) or copper(II) ion of the other dinuclear unit, with Zn(1)–O(3)* = 2.004(3) and Cu(2)–O(4)* = 1.924(4) Å bond distances, respectively. In the tetranuclear structure, the copper(II) ion coordinated by the tetradentate ligand assumes a square-planar geometry and the zinc(II) or the other copper(II) ion assumes a square-pyramidal coordination geometry with two phenoxo-oxygen atoms, two nitrogen atoms of bpy, and one amido oxygen atom. The magnetic susceptibility of 4 was reproduced by an equation derived from the H = −2J(S1·S2 + S3·S4) − 2J′(S2·S3 + S4·S1) spin Hamiltonian with J = −14.6 cm−1 and J′ = −4.0 cm−1.
  • Hiroshi Miyamae, Hideyuki Kudo, Goro Hihara, Kozo Sone
    Type: Accounts
    Subject area: AI
    1998 Volume 71 Issue 11 Pages 2621-2627
    Published: 1998
    Released: June 05, 2006
    JOURNALS RESTRICTED ACCESS
    Seven copper(II) complexes of the general formula [Cu(acac)(diam)]X were prepared, where acac and diam stand for acetylacetonate and one of the diamines in the title, and X for a bulky univalent anion, respectively. Their solvatochromism was compared with that of the corresponding complexes with N,N,N′,N′-tetramethylethylenediamine and related diamines, to see the effect of their bulky N-alkyl groups. X-ray crystal analyses showed that the perchlorates of N,N′- and N,N-diisopropyl complexes are apparently 6- and 5-coordinated, respectively, in their crystals, although their ClO4 ions are held extremely weakly and are easily driven out by solvent molecules in solution, leading to their solvatochromism. The Cu–N and Cu–O(acac) bond distances in the former, 199.5(4)/202.4(5) and 190.6(4)/190.1(4) pm, respectively, are similar to each other, while the Cu–N(isopropyl)2 distance, 206.4(9) pm, in the latter is notably longer than the Cu–NH2 distance, 196(1) pm.
  • Katsura Mochizuki, Kouki Ikeuchi, Takeshi Kondo
    1998 Volume 71 Issue 11 Pages 2629-2634
    Published: 1998
    Released: June 05, 2006
    JOURNALS RESTRICTED ACCESS
    The nickel(II) complex with L1 (5,5,7-trimethylcyclam: 5,5,7-trimethyl-1,4,8,11-tetrazacyclotetradecane), trans-[NiL1(H2O)2]Cl2·H2O, was isolated. An X-ray structural analysis gave strong evidence for the presence of steric interaction between the axial methyl substituent at the 5-position and the water molecule coordinating to the nickel(II) ion. The bimacrocyclic cobalt(III) complex with L3 (6,6-bi[5R(S),7S(R)-dimethyl-1,4,8,11-tetraazacyclotetradecane], trans-[Co2L3Cl4]Cl2, was synthesized and its structure was analyzed by X-ray crystallography, as well as the monomacrocyclic trans- and cis- dichlorocobalt(III) complexes with L2 (5R(S),7S(R)-dimethyl-1,4,8,11-tetraazacyclotetradecane). The structure of trans-[Co2L3Cl4]2+ was quite different from that of [Ni2L3]4+. In trans-[Co2L3Cl4]2+, the bridged six-membered chelate rings adopted an approximately twist-boat conformation. The steric interaction between the coordinated chloride anions on the cobalt(III) ion and the methyl substituents introduced at the 5- and 7-positions in the six-membered chelate ring was discussed.
  • Kazuaki Yamanari, Tatsuya Kawamoto, Yoshihiko Kushi, Takashi Komorita, ...
    Type: Accounts
    Subject area: AI
    1998 Volume 71 Issue 11 Pages 2635-2643
    Published: 1998
    Released: June 05, 2006
    JOURNALS RESTRICTED ACCESS
    The first ligand oxidation of sulfur donors of OC-6-3′2-[Co(pyet)2]+ [pyet = 2-[(2-pyridylmethyl)amino]ethanethiolate (1−)] by molecular dioxygen is attained in the presence of active charcoal. The oxidation products are characterized as one (thiolato)(sulfinato) complex OC-6-3′2-[Co(pyet)(pyesi)]+ (b; 82%), one (thiolato)(sulfenato) complex OC-6-3′2-[Co(pyet)(pyese)]+ (d; 14%) and a mixture of four bis(sulfenato) complexes OC-6-3′2-[Co(pyese)2]+ (h, i, j, and k; 4%), [pyese = 2-[(2-pyridylmethyl)amino]ethanesulfenate (1−); pyesi = 2-[(2-pyridylmethyl)amino]ethanesulfinate (1−)]. It is apparent that the route producing the monosulfinato complex is dominant in the dithiolatocobalt(III) complex as well as in the dithionickel(II) complexes. The isolation of OC-6-3′2-[Co(pyet)(pyese)]+, however, is extremely interesting because this complex is the first example of an oxidation product free from an O2.
  • Takaaki Harada, Chikako Takayama, Masatsugu Kajitani, Toru Sugiyama, T ...
    Type: Accounts
    Subject area: AI
    1998 Volume 71 Issue 11 Pages 2645-2653
    Published: 1998
    Released: June 05, 2006
    JOURNALS RESTRICTED ACCESS
    The addition of protic acids to (η5-cyclopentadienyl)(1-methylenethio)-κC,κS-ethylene-2-thiolato)cobalt(III) complexes (2) causes a Co–C bond cleavage in the three-membered cobaltathiirane ring to give (η5-cyclopentadienyl)(halo or acido)(1-methylthio-κS-ethylene-2-thiolato)cobalt(III) complexes (3). In the crystalline state, these complexes have either syn- or anti-configuration with respect to halo (or acido) and the methyl or substituted methyl group attached to S. In some cases, complexes 3 exist in equilibria between syn- and anti-stereoisomeric forms in solutions. In solutions, an exchange of the coordinated anions occurs very easily.
  • Abdol Reza Hajipour, Iraj Mohammadpoor -Baltork, Godaraz Kianfar
    1998 Volume 71 Issue 11 Pages 2655-2659
    Published: 1998
    Released: June 05, 2006
    JOURNALS RESTRICTED ACCESS
    Bis(1-benzyl-4-aza-1-azoniabicyclo[2.2.2]octane) peroxodisulfate (1), is readily prepared as an orange solid from commercially available 1,4-diazabicyclo[2.2.2]octane and potassium peroxodisulfate. This reagent easily converts hydrazones, semicarbazones, oximes, and alcohols to the corresponding carbonyl compounds with excellent yields.
  • Masahiko Taniguchi, Shuntaro Mataka, Thies Thiemann, Tsuyoshi Sawada, ...
    1998 Volume 71 Issue 11 Pages 2661-2668
    Published: 1998
    Released: June 05, 2006
    JOURNALS RESTRICTED ACCESS
    Dibenzo[3.3]orthocyclophanes ([3.3]OCPs) with a bicyclo[4.4.1]undecane substructure form charge-transfer (C-T) complexes with tetracyanoethylene (TCNE). 3,4 : 8,9-Dibenzobicyclo[4.4.1]undecane (9) and its 11-methylene derivative 8 are flexible molecules and take a chair-boat conformation. Complexes 8- and 9-TCNE exhibit the absorption maximum at ca. 420 nm, which coincides with the value for the TCNE complex of o-xylene. On the other hand, acetal 5, methylcarbinol 6, and dimethylmethylene derivative 7 are rigid, layered [3.3]OCPs with stacked benzene rings. Compounds 5, 6, and 7 form a 1 : 1 complex with TCNE in solution. The absorption maxima of the complexes at ca. 500 nm suggest an enhanced C-T complexation due to a π–π through-space interaction in 5, 6, and 7. A 2 : 1 complex of rigid [3.3]OCP 7 with TCNE crystallized from dichloromethane, while OCP 8 gave a red crystalline 2 : 3 complex with TCNE. X-ray crystallographic analyses of these two complexes is given.
  • Yoshio Ishino, Masatoshi Mihara, Shintaro Nishihama, Ikuzou Nishiguchi
    Type: Accounts
    Subject area: AI
    1998 Volume 71 Issue 11 Pages 2669-2672
    Published: 1998
    Released: June 05, 2006
    JOURNALS RESTRICTED ACCESS
    A combination of zinc metal and a catalytic amount of chlorotrimethylsilane has been found to promote the transformation of various aldehydes and ketones with gem-dichloro compounds, such as benzylidene dichloride (1a) and methyl dichloroacetate (1b), to the corresponding cross-coupling products, such as substituted styrene 3 and methyl acrylates 4 derivatives, under mild reaction conditions in THF. The E-isomer of the corresponding alkenes was obtained stereoselectively in good-to-excellent yields. The reaction serves as a very convenient one-pot procedure.
  • Masao Tsukayama, He Li, Ken Tsurumoto, Masaki Nishiuchi, Yasuhiko Kawa ...
    Type: Accounts
    Subject area: AI
    1998 Volume 71 Issue 11 Pages 2673-2680
    Published: 1998
    Released: June 05, 2006
    JOURNALS RESTRICTED ACCESS
    The palladium-catalyzed coupling reaction of 2′,4′,5,7-tetrakis(benzyloxy)-5′-iodoisoflavone (12), synthesized from the 5-iodochalcone 9, with 2-methyl-3-butyn-2-ol gave the corresponding 5′-(3-hydroxy-3-methyl-1-butynyl)isoflavone 13. The catalytic hydrogenation of 13 gave 2′,4′,5,7-tetrahydroxy-5′-(3-hydroxy-3-methylbutyl)isoflavone (2). Dehydration of the benzoate 14 of 2 afforded a mixture of 5′-(3-methyl-2-butenyl)isoflavone 15 and the isomer 5′-(3-methyl-3-butenyl)isoflavone 16. The separation of 15 was accomplished by a treatment of the mixture (15 and 16) with mercury(II) nitrate. Hydrolysis of 15 afforded 2′,4′,5,7-tetrahydroxy-5′-prenylisoflavone (allolicoisoflavone A) (1). In a similar manner, 2′,4′,5,7-tetrahydroxy-8-prenylisoflavone (2,3-dehydrokievitone) (3) and 2′,4′,5,7-tetrahydroxy-8-(3-hydroxy-3-methylbutyl)isoflavone (2,3-dehydrokievitone hydrate) (4) were synthesized from the corresponding 8-iodoisoflavone 22. The tetramethyl ether 5 of 3 was also prepared from the 8-iodotetramethoxyisoflavone 32.
  • Ikuo Taniguchi, Masashi Fujiwara, Kazunari Akiyoshi, Junzo Sunamoto
    Type: Accounts
    Subject area: AI
    1998 Volume 71 Issue 11 Pages 2681-2685
    Published: 1998
    Released: June 05, 2006
    JOURNALS RESTRICTED ACCESS
    A nanoparticle of cholesterol-bearing pullulan (CHP) self-aggregates effectively complexed with a neocarzinostatin chromophore (NCS-chr) in 0.5 M (1 M = 1 mol dm−3) AcONa/AcOH (pH 4.7) at 2 °C in the dark. The complex so obtained was very colloidally stable even after 4 d at 37 °C in a weak acidic medium. The complexed NCS-chr still maintained in vitro cytotoxicity to HeLa, HepG2, and 3′-mRLh-2 cells. In all cases, the cytotoxicity of the complex was higher than that of free NCS-chr itself. When the galactose moiety was additionally conjugated to CHP, the modified complex showed high cytotoxicity to a 3′-mRLh-2 cell. This cytotoxicity of the complex was almost comparable to that of intact NCS, which is ascribed to the galactose specific receptor-mediated endocytosis of the modified complex. This is the first finding to show that the complexed NCS-chr so obtained still maintains the strong cytotoxicity in vitro, and that the self-aggregate of hydrophobized polysaccharide (HPS) can nicely substitute for the apoprotein of NCS.
  • Satoru Furuta, Manabu Kuroboshi, Tamejiro Hiyama
    1998 Volume 71 Issue 11 Pages 2687-2694
    Published: 1998
    Released: June 05, 2006
    JOURNALS RESTRICTED ACCESS
    Upon treatment with n-Bu4NH2F3 and 1,3-dibromo-5,5-dimethylhydantoin, various organic sulfides underwent a Pummerer-type rearrangement, followed by fluorination, to give α-fluoro sulfides. The fluoro-Pummerer rearrangement, when applied to RCH(SMe)CF2SMe, gave trifluoro sulfides RCF(SMe)CF2SMe. When an HF-pyridine reagent was used as the fluorinating agent, an oxidative desulfurization–fluorination reaction occurred depending on the structure of the substrates.
  • Naoki Katano, Yoshiaki Sugihara, Akihiko Ishii, Juzo Nakayama
    Type: Accounts
    Subject area: AI
    1998 Volume 71 Issue 11 Pages 2695-2700
    Published: 1998
    Released: June 05, 2006
    JOURNALS RESTRICTED ACCESS
    Sulfur-bridged [1·n](2,5)thiophenophanes (n = 4—6) were prepared by cyclization of dibromo derivatives of the corresponding linear oligo(thio-2,5-thienylenes) (1) on reactions with Na2S. The best results were obtained by heating 1 and Na2S in the presence of Cs2CO3 in NMP (24% yield for n = 4, 16% for n = 5, and 10% for n = 6). The reactions gave less satisfactory results either in the presence of CuI (Cu2O) or in the absence of these additives. The results of the X-ray structural analyses of these three compounds are also reported.
  • Yuji Harada, Yasushi Mizobe, Youichi Ishii, Masanobu Hidai
    1998 Volume 71 Issue 11 Pages 2701-2708
    Published: 1998
    Released: June 05, 2006
    JOURNALS RESTRICTED ACCESS
    The hydrazido(2-) complexes [WCl2(NNH2)(L)(PMe2Ph)2] (L = PMe2Ph, CO), derived from the dinitrogen complex cis-[W(N2)2(PMe2Ph)4] (1), reacted with β-diketones R1COCHR2COR3 (R1 = Me, But, Ph; R2 = H, Me; R3 = Me, Et, But, Ph) to afford a series of diazoalkane complexes [WCl2(NN=CR1CHR2COR3)(L)(PMe2Ph)2]. The detailed structure of cis,mer-[WCl2(NN=CMeCH2COPh)(PMe2Ph)3] has been determined by X-ray analyses. These diazoalkane complexes were treated with a KOH/EtOH mixture to produce pyrazoles in moderate yields, whereas the reaction of 1 with a MeCOCH2COPh/KOH/EtOH mixture resulted in the direct formation of 5-methyl-3-phenylpyrazole.
  • Koji Matsuoka, Mikiko Terabatake, Yosuke Saito, Chiharu Hagihara, Yasu ...
    Type: Accounts
    Subject area: AI
    1998 Volume 71 Issue 11 Pages 2709-2713
    Published: 1998
    Released: June 05, 2006
    JOURNALS RESTRICTED ACCESS
    As a basic model reaction for assembling specific functional carbohydrate molecules on a novel core substance by making covalent bonds, an efficient one-pot reaction involving Birch reduction and a subsequent SN2 replacement was developed, employing trivalent and tetravalent carbosilane bromides as the core and monodeoxy-monomercapto-β-cyclodextrin as the functional carbohydrate. It was confirmed that carbosilane derivatives containing a suitable spacer molecule were of wide applicability as a new core substance for the construction of diverse functional materials.
  • Shinji Toyota, Akihiro Yasutomi, Hiroharu Kojima, Yuko Igarashi, Mitsu ...
    Type: Accounts
    Subject area: AI
    1998 Volume 71 Issue 11 Pages 2715-2720
    Published: 1998
    Released: June 05, 2006
    JOURNALS RESTRICTED ACCESS
    The title compound was prepared by addition of 4,5-dimethoxybenzyne to 9,9′-bianthryl. The rotational isomers, ap and ±sc, were separated by HPLC. The ±sc isomers were treated with sodium ethanethiolate to produce 3,3′-dihydroxy-2,2′-dimethoxy-9,9′-bitriptycyl, which was converted to the ester of (1S,5R,7R)-4-[(2-carboxy)benzoyl]-3-thia-4-azatricyclo[5.2.1.01,5]decane 3,3-dioxide. The resulting diastereomers were separated by HPLC. The isomers were hydrolyzed and methylated with dimethyl sulfate to yield optically active 2,2′,3,3′-tetramethoxy-9,9′-bitriptycyl. The absolute conformation of the tetramethoxy compound was determined by X-ray structure analysis of 3′-ester of (1S,5R,7R)-4-(2-carboxybenzoyl)-3-thia-4-azatricyclo[5.2.1.01,5]decane 3,3-dioxide derived from 3-hydroxy-2,2′,3′-trimethoxy-9,9′-bitriptycyl, followed by hydrolysis and then methylation. The CD spectrum of Msc-2,2′,3,3′-tetramethoxy-9,9′-bitriptycyl is reported.
  • Yoshinobu Izumi, Shunichi Kawanishi, Shinji Hara, Daishi Yoshikawa, Ta ...
    1998 Volume 71 Issue 11 Pages 2721-2725
    Published: 1998
    Released: June 05, 2006
    JOURNALS RESTRICTED ACCESS
    The irradiation effects of intense ultraviolet (UV) light from ArF and KrF excimer lasers on poly(vinylidene fluoride) (PVdF) were studied. The optical absorption spectroscopy made it clear that irradiation with ArF and KrF excimer laser light mainly caused the formation of diene and triene structures, respectively. From the dependence on the laser intensity it was found that ArF and KrF laser-induced reactions proceeded via single-photon and multi-photon processes, respectively. The wavelength dependence was explained by photochemical and photothermal effects of ArF and KrF excimer lasers, respectively. These results indicate that the distinction of the photo-reaction between the two is closely related to the difference in the absorption sites.
  • Takashi Yamada, Yusuke Yoshinaga, Toshio Okuhara
    1998 Volume 71 Issue 11 Pages 2727-2734
    Published: 1998
    Released: June 05, 2006
    JOURNALS RESTRICTED ACCESS
    An ultramicroporous heteropoly compound, Cs2.1H0.9PW12O40, was synthesized by a titration method using aqueous solutions of H3PW12O40 and Cs2CO3. Concentrations of the starting materials and the drop rate of Cs2CO3 solution were determined to synthesize Cs2.1H0.9PW12O40 having nearly uniform micropores and very low external surface area. The Dollimore-Heal method of N2 isotherms showed that Cs2.1H0.9PW12O40 prepared by the controlled conditions has no mesopores. Adsorption of various molecules having different sizes revealed that the micropore size of Cs2.1H0.9PW12O40 was in the range from 0.43 to 0.59 nm and the fraction of the external surface area was less than 3% of the total surface area. A model for the unique ultramicropores has been proposed on the basis of the pore size, pore volume, and the primary crystallite size, in which the ultramicropores are spaces formed between the crystal faces of the mcirocrystallites as the primary particles of Cs2.1H0.9PW12O40.
  • Meili Duan, Hiroaki Okamoto, Vladimir F. Petrov, Shunsuke Takenaka
    1998 Volume 71 Issue 11 Pages 2735-2739
    Published: 1998
    Released: June 05, 2006
    JOURNALS RESTRICTED ACCESS
    The liquid-crystalline properties of the homologous members of alkyl 4-(2-perfluorooctyl)ethoxy-3-R-benzoates (R = H (1), NO2 (3), Br (4)) show a new mesomorphic behavior. The lower alkyl (methyl–pentyl) esters of 1 exhibit a smectic A phase, and the smectic A-isotropic transition temperature tends to decrease with increasing the carbon number of the alkyl group, where the layer spacing of the smectic A phase tends to become short with increasing carbon chain length. The hexyl–decyl esters are non-mesogenic, and the after members again show a smectic A phase. The similar trend has been found for 3 and 4. Homologous members of alkyl 4-(2-perfluorodecyl)ethoxybenzoates (2) also show a similar thermal behavior. The smectic properties are strongly dependent on the relative constitution of the perfluoroalkyl group to the alkyl one within the molecule. The molecular arrangement of the smectic A phase is discussed.
feedback
Top