bluuebunny/crossref_metadata_2025 huggingface dataset:
Restricted Rotation Involving the Tetrahedral Carbon. XXXV. Stereodynamics of 9-(3,5-Dimethylbenzyl)triptycene Derivatives
Authors: Yamamoto Gaku , Oki Michinori
Published: July 2006

Stereodynamics of a variety of 9-(3,5-dimethylbenzyl)triptycene derivatives was studied. Atropisomerism about the bridgehead-to-methylene bond was realized in a triply peri-substituted derivative, 8,13-dichloro-1,4-dimethyl-9-(3,5-dimethylbenzy)triptycene: the activation enthalpy for the ap→±sc conversion was 26.4 kcal/mol. Barriers to rotation about the bridgehead-to-methylene bond in a variety of triply, doubly, and singly peri-substituted derivatives were obtained by DNMR method. DNMR behavior of the diastereotopic m-methyl groups in the benzyl moiety revealed the dual mechanisms of the methyl exchange process: rotation about the methylene-to-aryl bond by 180° without rotation about the bridgehead-to-methylene bond (“isolated rotation (IR)”) and rotation about the methylene-to-aryl bond by 180° synchronous with rotation about the bridgehead-to-methylene bond by 120° (“gear motion (GM)”). The GM process predominates in peri-unsubstituted derivatives, while the IR process predominates in triply peri-substituted ones.
The Crystal and Molecular Structure of Grayanotoxin XVI Hemihydrate
Authors: Furusaki Akio , Gasa Shinsei , Ikeda Ry\={u}z\={o} , Matsumoto Takeshi
Published: July 2006

The molecular structure of grayanotoxin XVI, C22H34O6, has been confirmed by means of an X-ray crystal analysis of its hemihydrate. The crystals are orthorhombic, with eight formula units in a unit cell with dimensions of a=17.503, b=37.933, and c=6.371 Å; the space group is P212121. 4180 unique intensity data were collected on a four-circle diffractometer with LiF-monochromated Cu Kα radiation. The structure was solved by the Monte Carlo direct method, using the 30 strongest reflections as the starting set, and was refined by the block-diagonal least-squares method. The final R value was 5.5%. The present analysis has revealed that the crystal used comprises about four parts of grayanotoxin XVI (6-O-acetylgrayanotoxin II) and one part of 10,20-dihydrograyanotoxin XVI. The molecules of the major component exist in two different conformations: One has the chair B-ring, and the other the twist-chair B-ring. About two-fifths of the molecules of the latter type are replaced at random by the molecules of the minor component.
Branched-chain Sugars. XXI. Synthesis of New Branched-chain Cyclitols Having neo-, myo-, and chiro-Configurations from 3-O-Benzyl-5,6-dideoxy-5-C-(1,3-dithian-2-yl)-6-nitro-d-galactofuranose and -l-altrofuranose
Authors: Iwakawa Masaharu , Yoshimura Juji , Funabash Masuo
Published: July 2006

The Michael addition of 2-lithio-1,3-dithiane to 3-O-benzyl-5,6-dideoxy-1,2-O-isopropylidene-6-nitro-β-l-arabino-hex-5-enofuranose afforded a 1 : 1.8 mixture of 3-O-benzyl-5,6-dideoxy-5-C-(1,3-dithian-2-yl)-1,2-O-isopropylidene-6-nitro-α-d-galactofuranose and-β-l-altrofuranose. Removal of the isopropylidene group and intra-molecular cyclization under weakly basic conditions afforded a mixture of branched-chain cyclitols having neo-, myo-, and chiro-configuration. A similar cyclization of the O-deisopropylidenated product of 3-O-benzyl-5,6-dideoxy-1,2-O-isopropylidene-6-nitro-5-C-(nitromethyl)-β-l-arabino-hexofuranose also afforded a mixture of cyclitols having neo-, myo-, and chiro-configuration. The results confirm the importance of two bulky groups such as benzyloxy at C-3 and 1,3-dithiane residue at C-5 in determining the stereodirection of cyclization.
Polarographic Studies on Ninhydrin in DMF and Dehydration from gem-Diol Structure
Authors: Ohmori Mitsuaki , Takagi Masanosuke
Published: July 2006

The d.c.-polarogram of ninhydrin (I) in DMF containing 0.1 M TEAP shows three cathodic waves whose E1⁄2 are −0.38, −0.65, and −1.23 V (vs. SCE), respectively. The first wave with a large maximum is attributed to one-electron reduction of 1,2,3-indantrione (II), the hydrated form of I, the second to one-electron reduction of I, and the third to one-electron reduction of the preceding electrochemical product from both I and II. CV Curves of I show three cathodic peaks, pc1, pc2, and pc3, and two anodic peaks, pa1 and pa2, showing reversible character of pc1 and pc3 but not of pc2. Different equilibria seem to take place between I and II in the bulk of the solution and at electrode surface. Hydration of II and dehydration of I in DMF were observed at 550 nm spectroscopically. A scheme is proposed for the electrolytic reduction of I in DMF.
Mechanochemical Reactions at High Pressures. I. The Design and Construction of the Apparatus and Preliminary Experiments
Authors: Ogo Yoshiaki , Nishiguchi Noboru , Okuri Yasuhiro
Published: July 2006

An apparatus for investigating mechanochemical reactions at high pressures of up to 50 kbar and preliminary experiments on acrylamide are described. The essentials of the apparatus are a rotating platen inserted in a Bridgman-type opposed-anvil press. The central platen is rotated by the force of an electric motor or by manual strokes under high pressure. The pressure distribution on the anvil surface was evaluated from the changes in the electric resistances of CdSe and CdTe as calibrants. The pressure observed at the center was 4.5 times the nominal load pressure. The phase-transition pressure of naphthalene was identified as about 25 kbar from the measurement of the pressure effect on the shearing strength. The mechanochemical behavior of acrylamide was investigated at room temperature and at static pressures of up to 15 kbar. The determinations of the IR spectrum, the ESR signal, the X-ray diffraction pattern, and the molecular weight confirmed that the reaction products were amorphous polyacrylamides and that the mechanical shear stress on the conversion of acrylamide to a polymer was exceedingly effective in comparison with static pressure.
The Stability of Spherical Micelles of Dodecyltrimethylammonium Chloride in Aqueous NaCl Solutions
Authors: Ozeki Sumio , Ikeda Shoichi
Published: July 2006

Light scattering from solutions of dodecyltrimethylammonium chloride in water and 4.00 M (1 M=1 mol dm−3) NaCl has been measured at 25 °C, and the critical micelle concentrations and the micellar molecular weights have been determined. The critical micelle concentration, when combined with the previous data, follows the linear Corrin-Harkins equation over the whole range of NaCl concentrations. The micellar molecular weight remains low, i.e., about 20000 even in the presence of 4.00 M NaCl, and the double-logarithmic relation between the micellar molecular weight and the ionic strength is represented by a straight line over the whole range of NaCl concentrations, when plotted together with the previous data. These results indicate that only spherical micelles are formed by dodecyltrimethylammonium chloride in the presence of added NaCl. The stability of the spherical micelle is attributed to the low degree of binding of Cl− on the cationic micelles.
Structure of Mercury Layer Deposited on Platinum and Hydrogen-evolution Reaction at the Mercury-coated Platinum Electrode
Authors: Yoshida Zenko
Published: July 2006

The thermal evaporation of mercury is investigated in order to ascertain the structure of mercury electrodeposited on platinum. At first, Pt2Hg is formed on platinum, and a hydrogen(H)-overpotential at the surface is identical with that at the mercury-free platinum. With the increase in the amount of mercury to more than the amount corresponding to PtHg, the H-overpotential increases. When a large amount of mercury is deposited, the layer is composed of three mercury compounds (Pt2Hg, Pt2Hg2, and PtHg4), metallic mercury, and adatom mercury. Even when a sufficiently large amount of mercury is deposited, e.g., several thousand atomic layers, the H-overpotential is much less than that at a hanging mercury drop electrode (HMDE). From the general relationship between the hydrogen evolution at a metal electrode and the work function of the metal, the change in the H-overpotential with the increase in the amount of mercury is attributable to the work-function change.
Photopolymerization of Methyl Methacrylate Using N,N-Dimethylformamide–Sulfur Dioxide Complex as the Photoinitiator
Authors: Ghosh Premamoy , Biswas Samir , Jana Subhankar
Published: July 2006

Photopolymerization of MMA in visible light was studied at 40 °C using DMF–SO2 complex as the photoinitiator. Initiator exponent was found to be 0.41 and monomer exponent varied between 1.12 to 1.50 depending on the nature of the solvent. Analysis of data revealed that the photopolymerization was induced by a free radical mechanism. Nonideality of the kinetics was explained on the basis of (a) monomer-dependent chain initiation and (b) initiator-dependent chain termination via degradative initiator transfer.
Effect of Halogen Substituents of Anion Radicals on the Electronic States of Crystalline Anion Radical Salts; K+ p-Chloranil\ewdot, K+ 2,5-Dibromo-3,6-dichloro-p-benzoquinone\ewdot, and K+ p-Bromanil\ewdot
Authors: Iida Yôichi
Published: July 2006

The intermolecular interactions in crystalline anion radical salts of K+  p-Chloranil\ewdot, K+ 2,5-Dibromo-3,6-dichloro-p-benzoquinone\ewdot, and K+  p-Bromanil\ewdot were examined in terms of one-dimensional half-occupied Hubbard model. Effect of substituents of the anion radicals on the crystal electronic states was discussed with the parameter values estimated by the Hubbard model.
Polymer-bound “Dimethylaminopyridine” as a Catalyst for Facile Ester Synthesis
Authors: Shinkai Seiji , Tsuji Hifumi , Hara Y\={o}ichiro , Manabe Osamu
Published: July 2006

Polystyrene beads which covalently link a dimethylaminopyridine unit act as a catalyst for ester synthesis by the DCC method. The polystyrene beads are reusable and the synthetic method is very simplified.
Mass Spectral Dehydration and Decarboxylation in Cyclic α-Hydroxy Acids, Alcohols, and Carboxylic Acids
Authors: Akkari Khalid H , Matta Michael S , Patrick Timothy B
Published: July 2006

The relative ease of mass spectral de-carboxylation is greater than the ease of mass spectral dehydration as determined from a comparison of the alcohols 1a–4a with acids 1b–4b. However, the relative ease is reversed in α-hydroxy acids 2c–4c; and dehydration predominates over decarboxylation.
The Concentration Dependence of the Apparent Molal Adiabatic Compressibility of Electrolytes in Water
Authors: Sakurai Masao , Komatsu Tsuyoshi , Nakagawa Tsurutaro
Published: July 2006

The apparent molal adiabatic compressibilities of NaCl, KCl, NaBr, and KBr in water have been measured in the concentration range from 0.01 to 1 mol kg−1 at 5, 25, and 45 °C. The results have been fitted to a Redlichtype equation: φKs=φKs°+SKsc1⁄2+BKsc. The limiting slope, SKs, was found experimentally as 5.6×10−4 at an ordinary temperature. Convenient equations for the conversion of adiabatic to isothermal compressibilities have been derived; the limiting slope for isothermal compressibility, SKT, should be larger than SKs at all the temperatures studied. The value of SKs determined experimentally has been compared with that predicted from the SKT values calculated by Mathieson and Conway, by Millero, and by Bradley and Pitzer.
Thermodynamic Studies of Thallium Halide Formation in Nonaqueous Solvents
Authors: Sasaki Yukio , Takizawa Masao , Umemoto Kisaburo , Matsuura Niro
Published: July 2006

The differences in the order of stability among halide ions for metal halogeno-complexes in nonaqueous solvents and water are examined by means of the thermodynamic constants for the formation of thallium halides of transfer from water to N,N-dimethylformamide (DMF) and propylene carbonate (PC). The thermodynamic constants for the formation of thallium halides were calculated from the solubility products of thallium halides. The differences in the order of stability for thallium halides were found to be dependent mainly on the enthalpy changes for the formation of thallium halides of transfer from water to DMF and PC, while the enthalpy changes of transfer for thallium halides are themselves largely influenced by the enthalpy changes for halide ions of transfer from water to DMF and PC.
Electrode Kinetics of Eu(III) Ion in the Presence of 1,4-Benzenedimethanol
Authors: Ikeda Osamu , Tsuura Katsuhiko , Tamura Hideo
Published: July 2006

In order to know the role of aromatic ring on the electrode kinetics, d. c. polarogram of Eu(III) ion was measured in the presence of 1,4-benzenedimethanol (1,4-BDM). The effect of the adsorption has been discussed by correlating the kinetic data to the adsorption behaviors of 1,4-BDM estimated from the electrocapillary curves. At the standard potential of Eu(III)/Eu(II) (−0.600 V vs. SCE), 1.4-BDM on the electrode changed its orientation from horizontal to vertical with an increase in the coverage. Both orientations showed an inhibition effect for the electroreduction of Eu(III) ion. When the coverage due to the horizontal orientation is less than 0.8, the inhibition was interpreted by an additional energy to deform the surface layer. On the other hand, the inhibition at full coverage due to both the horizontal and the vertical orientations was interpreted by the tunneling probability through the adsorbed layer differed in the thickness.
A Study of the Calcium Oxide–Water Vapor System by Means of the Transpiration Method
Authors: Matsumoto Kazutoshi , Sata Toshiyuki
Published: July 2006

The system of calcium oxide and water vapor was studied using the transpiration method. Under the conditions of a temperature range from 1678 to 2016 K and PH2O values from 1.2×10−2 to 4.7×10−1 atm, the predominant reaction in this system was found to be CaO(s)+H2O(g)=Ca(OH)2(g). The standard Gibbs free energy of the reaction is given by this equation: ΔGr°=(61300±820)−(12.8±0.48)T (cal/mol) in the present temperature range. From the thermochemical cycle, the dissociation energy, D0°(Ca–(OH)2), was estimated to be 206.4 kcal/mol.
Photocurrents in the ZnO and TiO2 Photoelectrochemical Cells Sensitized by Xanthene Dyes and Tetraphenylporphines. Effect of Substitution on the Electron Injection Processes
Authors: Matsumura Michio , Mitsuda Kenro , Yoshizawa Nobuyuki , Tsubomura Hiroshi
Published: July 2006

The photocurrents in zinc oxide and titanium dioxide electrodes sensitized by anionic xanthene dyes (Eosine Y, Phloxine B, Erythrosine, and Rose Bengal) and metal tetraphenylporphines were studied in aqueous solutions. The quantum efficiencies of the photocurrents sensitized by anionic xanthene dyes were unaffected by substitution of the dye with various halogen atoms, while those sensitized by the tetraphenylporphines were affected by changing the central metal. It is concluded from these results that the electron injection from the excited xanthene dyes to the semiconductor electrodes is a process so rapid (<<0.1 ns) that no internal quenching processes can compete with it, while that from the tetraphynelporphines is relatively slow competing with the internal deactivation processes. It is also concluded that the electron back transfer from the semiconductor conduction band to the oxdized dye decreases the sensitization efficiency.
Influence of Chemisorption of 2-Propanethiol on the Electrical Properties of Silver Oxide Compaction
Authors: Yamamoto Naoto , Tonomura Shoichiro , Matsuoka Tsugufumi , Amamiya Takashi , Tsubomura Hiroshi
Published: July 2006

The work function of silver oxide (Ag2O) decreased by as much as 0.8 eV on exposure to 2-propanethiol [(CH3)2CHSH]. The change in work function was irreversible at room temperature, and proportional to the amount of thiol in case where the partial pressure is low, but reversible at 200 °C. The conductivity of the Ag2O disk showed no substantial change by exposure to thiol. From the infrared absorption spectral studies, it was found that the thiol reacted with the silver oxide forming a (CH3)2CH–S–Ag group on the surface. The relationship between the work function and the chemical processes occurirng at the solid surface is discussed.
Recovery of Heavy Metals with Calcium Silicon. I. Its Stability in Water and Reducing Effect on Metal Ions
Authors: Tokunaga Shuzo , Uematsu Kitoshi , Nagawa Yoshinobu
Published: July 2006

The stability of calcium silicon in aqueous solutions was studied by determining dissolution rates of Ca and Si at a constant pH. Calcium silicon was found to be fairly stable in solutions of pH 3.0–8.0, at most less than 2.8%of Ca and 0.5% of Si being dissolved after 24 h. In a strong acid solution of pH 2.5 or less the dissolution rates of Ca and Si considerably increased. Ca dissolution reached a plateau and the whole amount of Ca did not dissolve even in a 3.0-mol dm−3 HCl solution, while Si dissolution continued to increase. Calcium silicon apparently reduces metal ions to the elemental state for metal ions having higher standard electrode potentials than Cd(II) ions except Ni(II) and Co(II) ions. For Ag(I) ions, nitrate ions interfere with the reduction, but chloride ions favor it. Reduction of Cr(VI) and Fe(III) ions terminated at the stage of Cr(III) and Fe(II). Pb(II), Cu(II), and Hg(II) ions were reduced to the metals, the acidity of the solution and the metal ion concentration not affecting the reduction. Calcium silicon is effective also for low-solubility compounds of these elements in suspension.
Alkali Metal Ion Exchange on Crystalline Zirconium Titanium Phosphate
Authors: Tomita Isao , Iwase Kenkichi , Saito Kazuhiko , Sugiyama Yoshiyuki
Published: July 2006

Ion-exchange studies of crystalline zirconium titanium phosphate with variable zirconium-to-titanium mole ratios have been extended to sodium-ion exchange on the exchangers with Zr-to-Ti mole ratios of 0.37 and 0.61, and to lithium and potassium ion exchange on the exchanger with a Zr-to-Ti mole ratio close to unity. In the sodium-ion exchange, a mono-sodium phase formed up to about a half of the exchange; then a disodium phase with a different amount of water of crystallization formed. In the lithium-ion exchange, the reaction proceeded with the formation of fully exchanged phases whose water content varied depending upon the environment in which the exchanger was placed during or after the reaction. The exchange amount of potassium ions was much less than that of sodium or lithium ions, and the ion exchange proceeded in parallel with an extensive hydrolysis of the exchanger. The half-exchanged phase could not be confirmed in this case. For the three alkali metal ions studied, the selectivity series was found as a function of loading, i.e., within the range of the load from 0 to 1.3 meq/g, the selectivity is in the order of Na+>K+>Li+, between 1.3 and 4.5 meq/g, it is Na+>Li+>K+, and above 4.5 meq/g loading, it turns out to be Li+>Na+>K+.
Effect of the Buffering Capacity of a Supporting Solution on Paper Electrophoretic Migrations of Adenine, Adenosine, and Adenosine Nucleotides
Authors: Kitaoka Yoshinori
Published: July 2006

Paper electrophoretic migrations of adenine, adenosine, and adenosine nucleotides as a function of pH-values of various supporting solutions have been studied. The buffering capacity of the supporting solution played an important role in the migration and is discussed along with the electroosmosis. The Rf-values of adenines in the supporting solutions are also presented.
The Addition of (Thioacyloxy)silanes to Carbonyl Compounds
Authors: Horii Toyokazu , Kawamura Shunichi , Nakabayashi Takeshige , Abe Yasuo
Published: July 2006

The reactions of (thioacyloxy)silane (O-trimethylsilyl thioacetate and thiobenzoate) with some aldehydes (propionaldehyde, butylaldehyde, and benzaldehyde) gave S-(1-substituted alkyl) thioacetates (S-[1-(trimethylsilyl-oxy)propyl, and -butyl] thioacetates, and S-[α-(trimethylsilyloxy)benzyl] thioacetate), and the three corresponding thiobenzoates respectively. The reactions were catalyzed by 1,8-diazabicyclo[5.4.0]undec-7-ene(DBU), and also by its salt with thiobenzoic acid.
Formation and Molecular Dynamics of Cycloamylose Inclusion Complexes with Phenylalanine
Authors: Inoue Yoshio , Miyata Yoshiaki
Published: July 2006

The molecular dynamics of the inclusion complexes of cycloamyloses with phenylalanine in aqueous solution at different pD have been studied by means of carbon-13 NMR spectroscopy. As host cycloamyloses we have chosen cyclohexaamylose, cycloheptaamylose, and cyclooctaamylose. The influences of the cavity size of cycloamyloses and of medium pD values on the molecular dynamics of inclusion complexes were studied by using the NT1η values, where T1 is the carbon-13 spin-lattice relaxation time, N the number of directly bonded proton to a given carbon, and η is the viscosity of solution. Upon complexation, the NT1η values of phenyl carbons of guest phenylalanine show larger decreases than those of other carbons, indicating that the guest forms the inclusion complexes with the host by the insertion of its phenyl ring into the host cavity even in the case of cyclooctaamylose. It was found that the strength of the dynamic coupling between host and guest depends on the cavity size and pD values of medium. The strongest coupling was observed for the cycloheptaamylose–phenylalanine system at pD 11.3, where the phenyl ring is deeply and tightly included into the cavity. The inclusion of phenyl ring is shallow and loose in the case of cyclohexaamylose and deep and loose in the case of cyclooctaamylose.
The Photo-Beckmann Rearrangement of Steroidal β,γ-Unsaturated Ketone Oximes
Authors: Suginome Hiroshi , Maeda Norio , Takahashi Yuko , Miyata Nobuyoshi
Published: July 2006

The photoreaction of 4,4-dimethylcholest-5-en-3-one oxime, a β,γ-unsaturated ketone oxime, has given two lactams, 4a,4a-dimethyl-3-aza-A-homocholest-5-en-4-one and 4a,4a-dimethyl-4-aza-A-homocholest-5-en-3-one resulting from photo-Beckmann rearrangement. 4,4,6-Trimethylcholest-5-en-3-one oxime behaved analogously on photolysis, yielding two lactams but accompanied by 4,6-dimethyl-4-methylene-3,4-secocholest-5-ene-3-nitrile as a minor product. In contrast, major products in the ordinary Beckmann rearrangement are nitriles resulting from the second order Beckmann rearrangement.
The Transformation of Jervine into 18-Functional D-Homo-C-norsteroids. IV. The Transformation of Jervine into (20R)-18,20β-Epoxy-3β-hydroxy-17β-ethyletiojervan-18-one 3-Acetate via (20R)-18,20β-Epoxy-3β-hydroxy-12α,17β-ethyletiojervan-11-one 3-Acetate
Authors: Suginome Hiroshi , Ono Hitoshi , Masamune Tadashi
Published: July 2006

Catalytic hydrogenation of (22S,25S)-N-acetyl-3β,23β-dihydroxyveratra-5,13(17)-dien-11-one 3-acetate over rhodium-platinum catalyst in acetic acid gave (22S,25S)-N-acetyl-3β,23β-dihydroxyveratranin-11 -one 3-acetate (2) in ca 70% yield, together with two minor products. Irradiation of 2 in benzene containing mercury(II) oxide and iodine gave 20-formyl-3β-hydroxy-12α,17β-ethyletiojervan-11-one 3-acetate (5) in 43% yield, accompanied by the 17-epimer of (22S,23R,25S)-N-acetyl-3β-hydroxy-5α-jervanin-11-one 3-acetate (4%). Aldehyde 5 was transformed into 3β-hydroxy-12α,17β-ethyletiojervane-11,20-dione 3-acetate (15) (79% yield) by photo- or coppercatalysed oxygenation of the corresponding enamine. Reduction of 15 with sodium borohydride gave 3β,20β-dihydroxy-12α,17β-ethyletiojervan-11-one 3-acetate (17) as a major product (69%), together with the 20-epimer. The hypoiodite reaction of 17 gave 18,20β-epoxy-3β-hydroxy-17β-ethyl-12α-etiojervan-11-one 3-acetate (19) in 92% yield. Hydrolysis of 19 resulted in the isomerization of the C/D ring junction to give 18,20β-epoxy-3β-hydroxy-17β-ethyletiojervan-11 -one (20), the first 18-functional C/D trans  D-homo-C-norsteroid ever prepared. Wolff-Kishner reduction of 20 gave the corresponding 11-deoxo compound; its acetylation followed by oxidation yielded 18,20β-epoxy-3β-hydroxy-17β-ethyletiojervan-18-one 3-acetate. The 11-oxo function of 19 can be reduced quite easily with lithium aluminum hydride to give the corresponding 11β-ol.
Reexamination of the Molecular Size Dependence of Diffusivities of Hydrocarbons in Natural Rubber
Authors: Kawakami Mitsuyasu , Iwanaga Hideaki , Kagawa Shuichi
Published: July 2006

Diffusion coefficients at zero concentration, D0, for hydrocarbon vapors in natural rubber have been determined, and their dependence on the size and shape (or length) of the penetrants has been reexamined. For normal hydrocarbons, D0 decreased gradually with increasing the number of carbon atoms up to 5 and then leveled off. For branched hydrocarbons, such as iso- and neo-paraffins, D0 was considerably lower than that for the corresponding normal ones. The dependence of D0 on the size and shape of penetrants could be explained by assuming that the principal resistance to diffusion is defined by the cross-sectional area at the most bulky portion of the major axis and also that an additional resistance due to the molecular length contributes for relatively lower hydrocarbons. The latter resistance was practically negligible for hydrocarbons with more than 4 carbon atoms in the major chain. The effective cross-sectional dimension could be estimated successfully in terms of the group dimension of Pauling.
The Electronic Absorption and Emission Spectra of Biphenylene-2,3-dione in Solutions
Authors: Kuboyama Akira
Published: July 2006

The electronic absorption and MCD spectra and phosphorescence spectra at 77 K, in solutions, have been studied by the use of P-P-P-method calculations. The longest-wavelength S–S ππ* band, near 370 nm, is proved to consist of two ππ* bands, the 1A1 and 1B2 bands. The nπ* absorption, and phosphorescence bands in various kinds of solutions are compared in many respects with those of the o-quinones previously studied.
The Reaction of Magnesium Hydroxide with Soluble Silica under Hydrothermal Conditions below the Critical Temperature
Authors: Muraishi Haruto
Published: July 2006

Mg(OH)2 powder packed into a basket was placed apart from solid SiO2 in an autoclave so that the SiO2 might react with the solid Mg(OH)2 in the state of soluble silica. At given temperatures of 250–360 °C, the Mg(OH)2 changed into talc(Mg3Si4O10(OH)2) through serpentine(Mg3Si2O5(OH)4): the reaction was a first-order consecutive-irreversible reaction which can be represented as:

Mg(OH)2\overset+SiO2→ Mg3Si2O5(OH)4\overset+SiO2→ Mg3Si4O10(OH)2.

The reaction rate of serpentine into talc as a single reaction was also first-order. The formation of serpentine was much faster than that of talc. The reaction rate depended on the silica concentration in the hydrothermal solution rather than on the reaction temperature. In the course of the reaction, the crystallite size of the Mg(OH)2 and the serpentine was hardly changed. In addition, the crystallite size of Mg(OH)2 did not affect that of the resulting serpentine. From these results, the rate-limiting step is presumed to be the formation of the crystal nuclei of the serpentine or talc.
Electrochemical Oxidation and Reduction of Flavin Mononucleotide Adsorbed on a Mercury Electrode Surface
Authors: Kakutani Tadaaki , Kano Kenji , Ando Shinji , Senda Mitsugi
Published: July 2006

The electrochemical redox reaction of flavin mononucleotide (FMN) adsorbed on a hanging mercury drop electrode was studied in a pH 6.9 phosphate buffer and a pH 4.9 acetate buffer by means of cyclic d.c. and phasese lective a.c. voltammetry. Both the oxidized and reduced forms of FMN arc strongly adsorbed on the electrode surface, and a stable adsorption layer of FMN((FMN)ad) is formed. The cyclic d.c. and a.c. voltammetric behavior of (FMN)ad is explained by equations for a two-step one-electron surface redox reaction. The formal standard redox potentials, semiquinone formation constants, and charge transfer-rate constants of the surface redox reaction of FMN at the mercury electrode were determined.
Phase Transition in Ammonium-d4 Sulfate as Studied by Heat Capacity Measurements between 3 and 300 K
Authors: Higashigaki Yoshiyuki , Chihara Hideaki
Published: July 2006

Molar heat capacities were determined of (ND4)2SO4 between 2.8 and 301 K. The phase transition at 223.94±0.03 K is of the first-order with a long tail extending down to 160 K. The overall heat and entropy of transition are 4270 J mol−1 and 20.35 JK−1 mol−1, respectively, the first-order portion contributing only 40%. The contraction of the molar volume at the transition was evaluated as 0.33 cm3 mol−1. The enthaply to misorient ions in an otherwise perfectly ordered lattice was derived from the low-temperature tail of the anomalous heat capacity. It was 12.0 kJ/mol of (ND4)2SO4, in reasonable agreement with 16 kJ mol−1 derived from O’Reilly-Tsang’s mean field theory. The present results support the order-disorder mechanism of the transition.
On the NMR Spectra of Some Substituted Pyridinium 2-Pyridylcarbonylmethylides
Authors: Matsubayashi Gen-etsu
Published: July 2006

The partial double-bond character of the ylide carbon-pyridinium nitrogen bond is discussed on the basis of the 1H and 13C NMR spectra of 4-cyano-(YCN), 4-methyl- (Ypic), and 3,5-dimethylpyridinium 2-pyridylcarbonylmethylide (Ylut). The α-proton signals of the 4-cyanopyridinium ring of YCN have been separately observed at low temperatures, indicating a hindered rotation around the ylide carbon-pyridinium nitrogen bond.
Separation of Metals on Sulfonated Diphenyl Phosphonate–Formaldehyde Resin in HCl–Organic Solvent Systems
Authors: Mori Hidehiko , Fujimura Yoshikazu , Takegami Yoshinobu
Published: July 2006

The distribution coefficients of several metal ions have been measured on sulfonated diphenyl phosphonate–formaldehyde resin in HCl–water miscible organic solvent solutions. Differences in the distribution coefficients are large enough to develop multicomponent separations. Particularly in HCl-propanone systems the separation of a complex mixture, Cd(II)–Zn(II)–Pb(II)–Cu(II)–Co(II)–Mn(II)–Mg(II), can be carried out chromatographically by sequential elution.
Potential Gradient Detector for Capillary Type Isotachophoresis
Authors: Nishiyama Fumitaka , Hirokawa Takeshi , Kiso Yoshiyuki
Published: July 2006

The potential gradient detector previously reported has been improved as regards mechanical stability and the contaminated electrodes can be easily exchanged with new ones. The linearity of step-height holds below the electrode voltage of 1.2 V (0.005 mol dm−3 aq HCl). The detection limit was 2.5×10−10 mol for adipic acid.
Synthesis of Thiol Esters by Carboxylic Trichlorobenzoic Anhydrides
Authors: Kawanami Yasuhiro , Dainobu Yuichiro , Inanaga Junji , Katsuki Tsutomu , Yamaguchi Masaru
Published: July 2006

Thiocarboxylic S-esters were obtained rapidly and in high yields by treating the mixed anhydrides prepared from 2,4,6-trichlorobenzoyl chloride and carboxylic acid, with various types of thiols in the presence of 4-dimethylaminopyridine.
Studies on the Synthesis of Sydnone Derivatives and Their Properties. XV. Synthesis of 4-Sydnonylmethyl Acetates
Authors: Yeh Mou-Yung , Tien Hsien-Ju , Chou Jiun-Tzer , Nonaka Tsutomu
Published: July 2006

The convenient methods for the synthesis of 4-sydnonylmethyl acetates from N-(4-sydnonylmethyl)morpholines, 4-sydnonylmethanols, or bis(4-sydnonylmethyl) ethers are described.
Effect of Ammonia Pre-treatment on Catalytic Activity of Metal Halide Catalyst for Reduction of Nitrogen Monoxide
Authors: Nishijima Akio , Kiyozumi Yoshimichi , Kurita Minoru , Hagiwara Hiroyuki , Ueno Akifumi , Sato Toshio , Todo Naoyuki
Published: July 2006

Effects of ammonia pre-treatment on catalytic activities of metal halides for the reduction of nitrogen monoxide are investigated in order to obtain highly active catalysts at lower temperatures. By the pre-treatment with NH3, some supported metal halide catalysts such as CeCl2, MnCl2, TiCl4, FeBr3, and CuCl2, showed higher activities than untreated ones.
Hydration of Quaternary Phosphonium Bromides, Bu4−nPhnPBr, in Chloroform
Authors: Wakabayashi Toshiki , Takaizumi Katsuko
Published: July 2006

Studies have been carried out on the hydration of quaternary phosphonium bromides, Bu4−nPhnPBr(n=0–4), in the chloroform phase by means of distribution equilibrium and 1H NMR spectroscopy, in order to clarify the difference between the alkyl- and aryl-substituted ions in ion–water interactions. The hydration constant for these bromides in the chloroform phase increases gradually from Bu4PBr to Bu2Ph2PBr, and then rapidly to BuPh3PBr and to Ph4PBr. The free energy of transfer from water to chloroform was evaluated for the non-hydrated species of the phosphonium bromides in the chloroform phase, the lowest being that for Bu2Ph2PBr. From 1H NMR spectra for water in the chloroform phase, it is concluded that the hydrated water molecule is hydrogen bonded with the anion of the onium salts. In the case of phenyl-rich cations such as BuPh3P+, Ph4P+, and Ph4As+ the water molecule occupies a site so close to the central atoms that it undergoes diamagnetic effects of phenyl groups. With phenyl-rich cations such hydration will play a certain role in their aqueous solutions.
New Scale of the Ionic Character of the Chemical Bond Using Multiconfiguration SCF Wave Functions
Authors: Ishida Kazuhiro , Kadowaki Shuichi , Yonezawa Teijiro
Published: July 2006

Two-configuration SCF wave functions constructed with multiconfiguration SCF localized-orbitals are obtained for several molecules, cations, and anions. The weights of the valence-bond resonance-structures are obtained from the wave functions for these molecules and molecular ions. A new formula of the ionic character of a chemical bond is proposed using these weights. For these neutral molecules, the values calculated from this formula are consistent with Pauling’s scale of the ionic character. The present formula is shown to be applicable even for molecular ions.
A New Interpretation of the Fast Relaxation in a Micellar Solution
Authors: Inoue Tohru , Tashiro Ryoichi , Shimozawa Ryosuke
Published: July 2006

Some contradictions are pointed out in the kinetic parameters of the fast relaxation in a micellar solution deduced from the previously proposed kinetic models. A modification of the previous models is proposed. The proposed model eliminates the contradictions and leads to a consistent interpretation of the experimental results.
The Effect of Crystallite Size of Nickel on the Enantioselectivity of Modified Nickel Catalysts
Authors: Nitta Yuriko , Sekine Fumimaro , Imanaka Toshinobu , Teranishi Shiichiro
Published: July 2006

Enantioselective hydrogenation of methyl acetoacetate to methyl 3-hydroxybutyrate with various unsupported nickel catalysts modified by (2R,3R)-tartaric acid was studied under mild conditions in order to elucidate the dependence of the selectivity upon the surface states of the catalysts. The catalyst with the larger crystallite size has the higher enantioselectivity, presumably because of the higher probability to obtain large ensembles of regularlyarranged nickel atoms in the catalyst surface for the modifier to adsorb strongly and regularly. The nickel boride catalyst has very low enantioselectivity, mainly due to its amorphous structure. The detrimental effect of additives (B, P, and Al in Ni–B, Ni–P, and R–Ni catalysts) was explained as the effect of their lowering the crystallinity of the catalysts.
A Dilatometric Study of Mesomorphic Transitions in Cholesteryl Oleyl Carbonate and Cholesteryl Oleate
Authors: Nakahara Masaru , Yoshimura Yosuke , Osugi Jiro
Published: July 2006

The volumetric behaviors of cholesteryl oleyl carbonate (COC) and cholesteryl oleate(CO) were investigated around the smectic(Sm)-cholesteric(Ch) and cholesteric-isotropic(I) transitions by using chromatographically purified materials. Both transitions showed marked pretransition phenomena in COC and CO. The transition volumes(ΔV) are; for COC ΔVSm-Ch=0.34 cm3 mol−1 at 22.8 °C and ΔVCh-I=0.66 cm3 mol−1 at 37.5 °C and for CO ΔVSm-Ch=0.88 cm3 mol−1 at 45.4 °C and ΔVCh-I=0.88 cm3 mol−1 at 50.7 °C. The Sm-Ch and Ch-I transitions are first order as predicted by mean-field theories. The pretransition volume around the Ch-I transition can be treated by the Landau-de Gennes theory for the first-order phase transition.
Observation of Mutual Diffusion Coefficients and Cooperative Motions in Binary Solutions of t-Butyl Alcohol–Water and 2-Butoxyethanol–Water
Authors: Ito Nobuyuki , Saito Koichi , Kato Tadashi , Fujiyama Tsunetake
Published: July 2006

Rayleigh scattering spectra were observed for the binary solutions of t-butyl alcohol(TBA)–water and 2-butoxyethanol (BE)–water. The observed line-widths were reduced to mutual diffusion coefficients. The observed concentration dependencies of the mutual diffusion coefficients were well explained by postulating the existence of “moving units”— a group of molecules which move together for a time much longer than the velocity autocorrelation time. The structure of the moving units which are formed in the TBA–water solution was (H2O)20TBA for XTBA\lesssim0.05, and 4(H2O)20TBA for XTBA\gtrsim0.05, where XTBA is the mole fraction of TBA. For the BE–water solution, the structure was found to be (H2O)50BE for XBE\lesssim0.02 and 3(H2O)50BE for XBE\gtrsim0.02. These results were compared with the results which had been obtained from the concentration dependencies of the mean-square concentration fluctuation values.
Thermodynamic Study of NH4Br and ND4Br Crystals under Constant High-pressures
Authors: Watanabe Kazuo , Oguni Masaharu , Matsuo Takasuke , Suga Hiroshi , Seki Syûzô
Published: July 2006

Heat capacities and volumes of NH4Br and ND4Br crystals were measured in the temperature range from 100 to 260 K at several constant pressures up to 110 MPa with a special attention paid to the behaviors around the point of ND4Br at 66 MPa and 202 K. The experimental results at an atmospheric pressure were in good agreement with the previously reported ones. The δ-γ and δ-β phase transitions were accompanied with expansion of the volume while the γ-β phase transition with contraction. Detailed phase diagram obtained for ND4Br disclosed that there was no maximum in any branch of the transition lines. The triple point was represented essentially as the point of intersection of the three straight lines. There was no pressure dependence of the total entropy of transition from the δ to β phase. The entropy values can be explained by the mechanism of the order-disorder change in the orientations of NH4+ tetrahedra. The existence of the heat capacity anomaly in the high temperature side of the δ-γ phase transition was discussed as due to the spatial fluctuation of domains of the γ and δ phases. An argument was put forward that the observed δ-γ phase transition was probably superheated. An additional anomalous heat-capacity peak was observed just below the triple point pressure in between the temperatures of the δ-γ and γ-β phase transitions, and explained in terms of the effects of the superheating in the δ-γ phase transition and of the coexistence of the δ and γ phases domains in the crystal.
The Electronic Structures of Linear Dicyano Complexes
Authors: Sano Mitsuru , Adachi Hirohiko , Yamatera Hideo
Published: July 2006

Molecular orbital (MO) calculations in the discrete variational Xα (DV-Xα) scheme have been made on linear dicyano complexes, [Ag(CN)2]−, [Au(CN)2]−, and [Hg(CN)2], to clarify their electronic structures. The valence X-ray photoelectron spectra (XPS) for these compounds are also reported. The calculated energy levels are consistent with the XPS results. The relative magnitudes of the bond overlap populations show a good correlation with those of the force constants obtained from infrared data. The calculated MO features show that the mixing of the metal (n+1)s orbital is important in stabilizing the linear L–M–L bonds, especially in the partial cancellation of the antibonding character of the σg-type highest occupied molecular orbital.
The Continuous Determination of Filtered Chemical-oxygen Demand with Potassium Dichromate by Means of Flow-injection Analysis
Authors: Korenaga Takashi
Published: July 2006

A useful method, based on the principle of flow-injection analysis, whose flow system is physically analyzed to operate the apparatus, is proposed for the continuous and rapid determination of chemical-oxygen demand (COD) as a dichromate value in organic-waste-water samples. Potassium dichromate in sulfuric acid (1+2) is pumped as an oxidizing and spectrophotometric reagent stream, and d-glucose is successfully used as a standard substance for COD. A redox reaction between potassium dichromate and organic COD substances is carried out at 100 °C in the poly(tetrafluoroethylene) tubing (0.6 mm i.d.×50 m) of the system. The peaks, obtained at 445 nm in the recordings, show a good reproducibility over a wide range of COD values. A sampling rate of 10 samples per hour is achieved even when the residence time is 30 min. The precision with this method is 1.3%. Chloride up to 200 mg dm−3 does not interfere with the determination even if silver or mercury salts are not added.
Kinetics of Thermal Pyridine Dissociation of Ni(N-arylsalicylideneaminato)2(pyridine)2 in Solid Phase
Authors: Miyokawa Kikuo , Hirashima Hidenori , Masuda Isao
Published: July 2006

The kinetics of the thermal pyridine dissociation reactions of Ni[N-(R-C6H4)salam]2py2, where R=H(1), p-F(2), p-CH3O(3), p-CH3(4), p-Cl(5), and p-Br(6), in solid phase, were analyzed by the isothermal weight-loss measurements. On pyrolysis, these pyridine adducts with an octahedral coordination geometry of Ni(II) liberated pyridine to leave products with the formula Ni[N-(R-C6H4)salam]2. The product obtained from 2 was the diamagnetic monomer, those from 4–6 were paramagnetic polymers with μeff=(3.11–3.30) μB, and that from 3 was paramagnetic with an intermediary moment of μeff=1.45 μB. Reaction mechanisms were different depending on the nature of R: 2 followed the contracting disk equation with E=163 kJ/mol; 3–6 followed the contracting disk equation in the initial period of the reaction (the Ea values were 97 for 3, 134 for 4, 173 for 5, and 172 kJ/mol for 6) and then all except 3 followed Jandar’s equation, in the subsequent period. These Ea values were considered to reflect the bond stability between the central Ni(II) ion and the axial pyridine ligands; these values increased with an increase in the electron-withdrawing property of R. The pyridine dissociation reaction may give rise to the complexes of the monomeric square-planar or to those of the associated, polymeric octahedral structure. Which result occurs does not depend only on the tendency of the central Ni(II) ion to accept, at the apical positions, the coordinate bond from the adjacent molecules.
Stereochemistry of Bis[N-(2,6-diisopropylphenyl)salicylideneaminato]copper(II) and nickel(II) Complexes
Authors: Yamada Shoichiro , Yamanouchi Kuniko
Published: July 2006

Bis[N-(2,6-diisopropylphenyl)salicylideneaminato]copper(II) and nickel(II) complexes have been synthesized. Their configurations in the solid state, in chloroform, and in pyridine have been examined and discussed in comparison with those of the related complexes.
Spirans. XXII. Spiroconjugation in Heteraspirans Studied by UV and 13C NMR Spectra
Authors: Smolinski Stefan , Balazy Michal , Iwamura Hiizu , Sugawara Tadashi , Kawada Yuzo , Iwamura Michiko
Published: July 2006

UV and 13C NMR spectra of spirocyclic orthocarbonates, a spirobi(benzodithiepin) and a spirobi(naphthopyran) have been measured and compared with those of the “half compounds” to see the spiroconjugation effect. Whereas batho- and hyperchromic shifts are usually brought about by spiroconjugation, hypso- and hypochromic effects have been observed for 2,2′-spirobi[1,3-benzodioxole]. Through-bond interaction similar to the mechanism for the anomeric effect is considered to be operative in attenuating the electron release from the orthocarbonate moiety to the benzene chromophore. The downfield shifts of 20–25 and ca. 40 ppm were noted for the spirocarbons of the conformationally flexible and rigid orthocarbonates, respectively, as compared to the corresponding methylene carbons of the half compounds. The largest paramagnetic shift of 66.3 ppm is observed for the orthothiocarbonate and attributed to the presence of the low-lying d-orbitals due to through-space interaction of the four sulfur atoms.
Photocycloadditions of Benzophenone with 6-Methylenetricyclo[3.2.1.02,7]oct-3-en-8-one and Its Related Compounds. Di-π-methane Photorearrangement of the Primary Photocycloadducts
Authors: Nitta Makoto , Sugiyama Hiroshi
Published: July 2006

The photocycloadditions of benzophenone with constrained divinylcyclopropanes such as 1,5-dimethyl- and 1,3,5-trimethyl-6-methylenetricyclo[3.2.1.02,7]oct-3-en-8-ones, 5,8-dimethyl-9-methylenetricyclo[3.3.1.2,8] non-3-en-6-one, 5,8-dimethyl-9-methylenetricyclo[3.3.1.02,8]non-3-en-7-one, and their corresponding alcohols were investigated. In no cases, was oxetane formation observed but the formal [2+6] cycloaddition which originates from the cleavage of a cyclopropane ring was observed. In the case of the compounds which have a carbonyl function, benzophenone sensitized di-π-methane or oxadi-π-methane rearrangement of the primary photocycloadducts was observed. The mechanism of the formation of photoproducts is discussed with emphasis on (i) the nature of the intermediates having tricyclo[3.2.1.02,7]oct-3-en-6-yl and tricyclo[3.3.1.02,8]non-3-en-9-yl radicals, (ii) the regioselectivity of the di-π-methane or oxadi-π-methane rearrangement of the primary photocycloadducts.
The Preparation of Ti5S8
Authors: Saeki Masanobu , Onoda Mitsuko
Published: July 2006

Ti5S8 (12R type), which had never been prepared in a pure state, was obtained as a single phase by the chemical-transport method. The conditions for the preparation were determined experimentally. The existence range of the phase was examined for composition and temperature.
A Dimethyl Sulfoxide-mediated Oxidation of Arylalkyl and Alkyl Alcohols to Corresponding Aldehydes and Ketones via Tropolonyl Ethers
Authors: Takeshita Hitoshi , Mametsuka Hiroaki , Matsuo Norihide
Published: July 2006

The arylmethyl and diarylmethyl ethers of tropolones were oxidized to the corresponding carbonyl derivatives by heating in dimethyl sulfoxide. The free alcohols were oxidized at a much slower rate, suggesting that some sort of DMSO-linked intermediates are responsible for the oxidation. Inertness of free alcohols was proven by means of the cross-over experiments, including deuterium-labelling. This oxidation was applicable to alkyl ethers, but not to alkenyl ethers, which are known to cause the Claisen-rearrangement.
The Cycloisomerization Reaction of [2.2]Metacyclophanes to 1,2,3,3a,4,5-Hexahydropyrenes. Substituent Effects and Directional Selectivity
Authors: Yamagishi Takeshi , Torizuka Koichi , Sato Takeo
Published: July 2006

Substituent effects and directional selectivity in iodine-induced cycloisomerization reaction of [2.2]metacyclophane were tested using several derivatives of the latter. The reaction was found to be highly selective, and electron-donating groups gave a hexahydropyrene preserving a substituted aryl ring. On the other hand, an alkyl group ortho to the bridge gave a hexahydropyrene with a hydrogenated substituted ring.
The Total Synthesis of Antibiotic Fortimicin B
Authors: Honda Yutaka , Suami Tetsuo
Published: July 2006

The total synthesis of antibiotic fortimicin B (1b) is described. The sugar component of 1b: 6-epi-purpurosamine B was converted to the sugar chloride: 2,6-bis(2,4-dinitrophenylamino)-2,3,4,6,7-pentadeoxy-β-l-lyxo-heptopyranosyl chloride (5). The aminocyclitol component of 1b: fortamine B was also converted to the partially protected aglycone (9). The condensation of aglycone 9 with the sugar chloride 5 gave the desired condensation product in 37% yield. The analogous condensation of the Dl-form of the aglycone with 5 afforded the same condensation product in 19% yield, it was then converted to 1b by step-by-step hydrolysis.