bluuebunny/crossref_metadata_2025 huggingface dataset:
Ring Opening of Oxiranes by Trimethylsilyl Trifluoromethanesulfonate
Authors: Murata Sizuaki , Suzuki Masaaki , Noyori Ryoji
Published: July 2006

Trimethylsilyl trifluoromethanesulfonate promotes ring opening reactions of oxirane derivatives. The reaction course is highly affected by the structures and substitution pattern of the substrates. Tetra-, tri-, and 2,2-disubstituted oxiranes and simple cycloalkene oxides are converted to the corresponding allylic alcohol trimethylsilyl ethers. The overall transformation is interpreted in terms of trans addition of the silyl trifluoromethanesulfonate to the oxirane ring followed by base-promoted anti elimination of a trifluoromethanesulfonic acid element. 2,3-Dialkyl- or monoalkyloxiranes isomerize to the corresponding ketones and aldehydes, respectively. (Z)-Cyclooctene oxide undergoes the transannular reaction to give endo-cis-2-trimethylsiloxybicyclo[3.3.0]octane. The reaction of 6-methyl-5-hepten-2-one oxide produces 2,2,6-trimethyl-3-trimethylsiloxy-3,4-dihydro-2H-pyran. 1,2-Methyl migration takes place in the reaction of (E)-3α-t-butyldimethylsiloxy-5α-pregnene 17α,20-oxide to afford 3α-t-butyldimethylsiloxy-17β-methyl-17α-[1-(trimethylsiloxy)ethyl]-18-nor-5α-androst-13(14)-ene. α-Pinene oxide gives trans-carveol trimethylsilyl ether.
The Reaction of Isocyanides with Halogens or N-Halosuccinimides and Alcohols
Authors: Yamada Hideyo , Wada Yasuo , Tanimoto Shigeo , Okano Masaya
Published: July 2006

The reaction of aliphatic isocyanides with bromine or chlorine in primary alcohols, followed by hydrolysis, afforded the corresponding carbamates in moderate yields, together with various amounts of amines. Bromine was superior to chlorine as a halogen source for the formation of carbamates. unexpectedly, the addition of HgCl2 resulted in a decrease in the carbamate yield. When N-halosuccinimides were used in the place of halogens, an additional formation of the succinimide-incorporated product was observed to some extent.
The Electric-field Analyses of a System with an Axial Symmetry and Its Application to the Infrared Intensity
Authors: Kanesaka Isao , Hiroya Yoshihiro , Kawai Kiyoyasu
Published: July 2006

The method of solving the Laplace equation for a system with axial symmetry is formulated in terms of the finite element method. The molecule having C3V point symmetry is assumed to have axial symmetry, and the van der Waals radii of the component atoms are used to estimate the shape of the central molecule. The method is applied to the IR intensity of the C≡N stretching mode of acetonitrile in various states. The observed intensities are adequately explained by the use of the local and reaction fields, except for the intensity in a solution diluted infinitely in chloroform. The intensity in chloroform can, however, reasonably be explained by taking the hydrogen bond into consideration.
The Interaction of a Neutral Polymer with Small Ions in Solution. I. A Method for the Analysis of Ion Binding to a Neutral Polymer
Authors: Awano Hiroshi , Ono Katsumichi , Murakami Kenkichi
Published: July 2006

A method for the analysis of ion binding to a neutral polymer, such as poly(oxyethylene) (POE), based on the one-dimensional lattice model has been proposed. The grand partition function for the one-dimensional lattice has been given by the product of the statistical weight matrix. Interaction between the ions bound to the lattice points has been well approximated by the Debye-Hückel pair-by-pair potential, and the distance between the bound ions has been assumed to be the root mean square end-to-end distance of the partial chain. Based on the model, an equilibrium constant has been defined which is referred to the binding constant.
Theoretical Considerations of the Dimer-formation Energy and Electronic Structures of the Monomer and Dimer of the 2-Pyridone by the Molecular Orbital Method
Authors: Inuzuka Kozo , Fujimoto Akira
Published: July 2006

When the dimer-formation energy of 2-pyridone was measured by means of 1H-NMR spectroscopy, the value of 65.3 kJ mol−1 was obtained. It is much larger than the hydrogen-bond energies which are generally observed for the C=O···H–N system. The dimer-formation energy of 2-pyridone was calculated by means of the CNDO/2 method; its formation energy (−ΔH) was estimated to be 68.2 kJ mol−1. The electronic structures of the monomer and dimer of 2-pyridone were calculated by means of the CNDO method with configuration interaction (CNDO/CI) in order to clarify the previous band assignment of the UV spectrum of 2-pyridone. According to the calculated results, the absorption bands at 305 and 228 nm in isooctane (2,2,4-trimethylpentane) were assigned to the monomer, while those at 297.5 and 230.5 nm were assigned to the dimer.
The Molecular Structure of Trimethylphosphine–Boron Triiodide as Studied by Gas-phase Electron Diffraction
Authors: Iijima Kinya , Koshimizu Eiichi , Shibata Shuzo
Published: July 2006

The molecular structure of trimethylphosphine-boron triiodide (CH3)3P·BI3 has been determined by means of gas-electron diffraction. The molecular parameters and their uncertainties were rg(B–I)=2.233±0.003 Å, rg(P–B)=1.947±0.011 Å, rg(C–P)=1.809±0.003 Å, rg(C–H)=1.094±0.008 Å, ∠IBI=111.6±0.3°, and ∠CPC=106.0±0.5°. The gaseous molecule was rigid with respect to the rotational vibration around the P–B bond.
The Stereochemistry and Reactivity of Metal–Schiff Base Complexes. V. The Solvent Effect on the Stereoselectivity of Cobalt(III) Complexes Containing a sal2en-type Schiff Base and l-Amino Acid
Authors: Fujii Yuki , Kuwana Yasuo , Takahashi Sozo , Shimizu Keiko , Hiroi Kumiko
Published: July 2006

The solvent effect on the stereoselectivity between Λ- and Δ-β2-diastereoisomers of cobalt(III) complexes with the general formula of [Co(Schiff base)(l-aa)], where Schiff base represents sal2en2−, α-Me-sal2en2−, and 5,6-benzo-sal2en2−, and where l-aa denotes l-alaninate, l-valinate, l-methioninate, and l-phenylalaninate, was studied. Generally, the Λ-β2-isomer was more stable than the Δ-β2-isomer in solution, and the stereoselectivity of all the l-ala-complexes and of the l-met-complex with 5,6-benzo-sal2en increased in the following order of solvents : acetone=DMF≤t-BuOH<s-BuOH<i-PrOH<n-BuOH<n-PrOH<EtOH<MeOH. On the other hand, the stereoselectivity of l-val- and l-phe-complexes with sal2en and 5,6-benzo-sal2en increased in the following order : acetone=DMF<MeOH<EtOH<n-PrOH<n-BuOH<i-PrOH<s-BuOH<t-BuOH. In the case of 5,6-benzo-sal2en complexes with l-val and l-ile, the Δ-β2-isomer was preferred rather than the Λ-β2-isomer in acetone and DMF with 8–13% stereoselectivity. From the spectroscopic evidence, a hydrogen bonding between the OH group of alcoholic solvents and phenolic oxygen atoms of a Schiff base ligand was assummed, and the above phenomena were explained in terms of the steric difference between the Λ- and Δ-β2-isomers for the solvation with the alcoholic solvents by means of the hydrogen bonding.
Synthesis, Ion Exchange Properties, and Analytical Applications of a Novel Tin(IV)-edta Ion Exchanger
Authors: Ashfaq Nabi Syed , Rao Rifaqat Ali Khan
Published: July 2006

Tin(IV)-edta compound has been synthesized by mixing aqueous solutions of tin(IV) chloride and disodium salt of ethylenediaminetetraacetic acid (EDTA=H4 edta) in different conditions. The most stable sample is prepared by mixing 0.1 mol dm−3 solution of tin(IV) chloride with 0.1 mol dm−3 solution of disodium salt of edta in the volume ratio of 3:2 at pH 2.5 and refluxing the mixture for 16 h. Ion exchange capacities of the material for alkali metals are significantly smaller (0.26–0.20 mequiv./g) than for alkaline earths (0.74–0.40 mequiv./g). The thermal and chemical stability of this material has been compared with amine-tin hexacyanoferrate(II). Analytical importance of this material has been established by achieving a number of quantitative separations on its columns.
Gas-chromatographic Measurements of Dinitrogen Oxide in Surface Air
Authors: Hirota Michio , Muramatsu Hisafumi
Published: July 2006

The mixing ratio of N2O in surface air was measured at Tsukuba between July and September, 1980. The mean was 0.325 ppm, and the standard deviation was 0.008 ppm. No difference in the N2O content was found between the air blowing from the northeast or south and calm air.
The Preparation and Catalytic Properties of the Silica-supported Rhodium Complex
Authors: Okano Tamon , Kobayashi Teruyuki , Konishi Hisatoshi , Kiji Jitsuo
Published: July 2006

The RhH2(O2COH)[P(i-Pr)3]2 complex is attached to the phosphinated silica prepared from a new linking agent, Ph2PCH2CH2CH2Si(OCH3)3. The supported complex is an active catalyst for the hydrogenation of methyl cinnamate with CO and H2O, and it can be used repeatedly with little loss of activity, whereas the polystyrene-supported one is not recoverable because of the insufficient complexation of the rhodium.
Ozonization of Organic Compounds. VI. Relative Reactivity of Protic Solvents toward Carbonyl Oxide
Authors: Yamamoto Yorihiro , Niki Etsuo , Kamiya Yoshio
Published: July 2006

Tetramethylethylene was ozonized at 0 °C in several binary protic solvents and the relative reactivities of the solvents toward acetone carbonyl oxide were measured. The reactivity was found to decrease in the order methanol, ethanol, propyl alcohol, isopropyl alcohol, water, t-butyl alcohol, and acetic acid.
An Experimental Approach to the Prebiotic Synthesis of α-Amino Acids under UV Irradiation in Aqueous Medium
Authors: Nishizawa Masato , Egami Fujio
Published: July 2006

N-Oxaloglycine obtained from a glyoxylic acid and ammonia mixture was allowed to produce various α-amino acids under UV irradiation using an alkylating agent such as an olefin in the presence of acetone as the initiator. Aspartic acid, norvaline, valine, leucine, phenylalanine, and tyrosine were identified by TLC, amino acid analysis, GC, and GCMS techniques.
Trimethylsilyl Triflate Induced Reaction of Humulene 6,7-Epoxide. Cyclization to 5-Hydroxy-4,8,11,11-tetramethyltricyclo[6.3.0.02,4]undec-9-ene
Authors: Shirahama Haruhisa , Murata Shizuaki , Fujita Terunori , Chhabra Baldev R , Noyori Ryoji , Matsumoto Takeshi
Published: July 2006

Humulene 6,7-epoxide was converted by treatment with trimethylsilyl triflate to 5-hydroxy-4,8,11,11-tetramethyl[6.3.0.02,4]undec-9-ene in 81% yield.
Synthesis, Luminescence Quantum Yields, and Lifetimes of Trischelated Ruthenium(II) Mixed-ligand Complexes Including 3,3′-Dimethyl-2,2′-bipyridyl
Authors: Nakamaru Katsumi
Published: July 2006

New five complexes of the type of [RuL3−x(dmby)x]X2(x=1,2,3, L=2,2′-bipyridyl or 1,10-phenanthroline, dmby=3,3′-dimethyl-2,2′-bipyridyl, X=halide ion) have been synthesized in order to investigate the effects of two methyl groups of dmby on the absorption and emission spectra, luminescence quantum yields, and lifetimes. Values of the radiative and nonradiative rate constants have been calculated from these data at 77 K. Although the absorption and emission maxima and the lifetimes are not much affected by the dmby ligand substitution, the molar extinction coefficients and emission quantum yields are decreased compared with trischelated complexes of the parent bipyridyl or phenanthroline ligands. At 25 °C the emission yields of the complexes containing dmby decrease by 3–4 orders of magnitude than at 77 K. Possible causes of the decrease in the quantum yields are discussed.
The Oxidation of Carbon Monoxide on Pt/Al2O3 Containing a Metal Oxide
Authors: Kosaki Yukio , Miyamoto Akira , Murakami Yuichi
Published: July 2006

By using a three-way catalyst containing a metal oxide, CO is removed as CO2 even in the “rich” region of the air/fuel ratio. In order to elucidate the mechanism of this action of the added metal oxide, the reaction of CO with O2 on a Pt–V2O5/Al2O3 catalyst was investigated using a rectangular pulse-reaction apparatus. In the CO–O2 reaction on a Pt/Al2O3 catalyst, a significant amount of unreacted CO was exhausted in the “rich” region of the reactants. Furthermore, the conversion of CO decreased markedly with an increase in the CO/O2 ratio in the reactants. In the CO–O2 reaction on the Pt–V2O5/Al2O3 catalyst, on the other hand, the conversion of CO was high and did not decrease markedly with an increase in the CO/O2 ratio in the “rich” region. As for the reaction on the Pt–V2O5/Al2O3 at 558 K and above, the CO was completely removed as CO2 at any of the CO/O2 ratios examined. These effects of the added V2O5 were found to be due to: (i) the reaction of CO with an oxygen of V2O5 in the Pt–2O5/Al2O3 catalyst and (ii) the enhanced oxidation of CO with a gaseous O2 on the Pt/Al2O3 catalyst upon the addition of V2O5. On the basis of the kinetics of the oxidation of CO with the oxygen of V2O5 in the Pt–V2O5/Al2O3 and Pt black–V2O5 mixtures, its mechanism was proposed to be as follows; the oxygen of V2O5 at the Pt–V2O5 interface is activated by contact with Pt (this activated oxygen is denoted by [Pt···O···V]). The oxidation of CO with the oxygen of the Pt–V2O5/Al2O3 and Pt black–V2O5 mixtures proceeds according to the following two steps. Step I is the reaction of a gaseous CO with the active oxygen at the Pt–V2O5 interface, [Pt···O···V], to form CO2 and a reduced site, [Pt V]. Step II is the oxidation of the reduced site with the bulk oxygen in V2O5 to reproduce [Pt···O···V]. The enhanced oxidation of CO with a gaseous O2 caused by the addition of V2O5 to Pt/Al2O3 was found also to be understandable in terms of the active site, [Pt···O···V], where the reduced site, [Pt V], is oxidized by the gaseous O2 to reproduce [Pt···O···V] instead of the bulk oxygen in V2O5.
Electronic Structures of Pyridinols and of Their Anions and Cations
Authors: Morita Hiroshi , Kwiatkowski Józef S , Tempczyk Anna
Published: July 2006

Electronic structures of the lactim and lactam forms of 2-, 3-, and 4-pyridinols, and of their anions and protonated cations were calculated by a modified CNDO-CI (mCNDO-CI), CNDO/S-CI, and a modified π-SCF-MO-CI methods. The theoretical results agree well with the observed spectra of both the neutral and ionic species, and predict satisfactorily the shorter wavelength shift of lower excited π-π* and n-π* bands of the lactim form compared to the corresponding bands of the lactam form. The π-π* assignment to the lowest triplet states of 2- and 4-pyridones, and of 2- and 3-pyridinols, together with the n-π* assignment to the lowest singlet state of 4-pyridone was predicted by the mCNDO-CI method, in agreement with the suggestion based on emission properties. The orbital energies calculated by the mCNDO method were compared with the observed photo-electron spectra; the results show that the fourth highest occupied orbital is π-orbital in 2- and 3-pyridinols, and σ-orbital in 4-pyridinol and 4-pyridone.
Elementary Patterns in Protein-Nucleic Acid Interactions. IV. Crystal Structure of 3-(Adenin-9-yl)propionamide : 1-Methylthymine (1 : 1) Complex Dihydrate
Authors: Takimoto Midori , Takenaka Akio , Sasada Yoshio
Published: July 2006

As a ternary interaction model between adenine:thymine base pair and carbamoyl group, 3-(adenin-9-yl)-propionamide: 1-methylthymine complex was prepared and its crystal structure was examined. The crystal exhibits a disordered structure, and the structure unit is a monoclinic cell with dimensions a=11.368(1), b=6.909(1), c=12.708(2) Å, and β=114.49(1)°. The space group is P21 and the unit cell contains two complexes and four water molecules. The base pairing pattern between adenine and thymine is the Hoogsteen type. The carbamoyl group is hydrogen-bonded to N(A1) of adenine in this base pair, the distance NH···N(A1) being 2.94(2) Å. With two kinds of hydrogen bonds of the carbamoyl group, NH···N(A1) above-mentioned and NH···O(carbamoyl), the 3-(adenin-9-yl)propionamide molecules form a sheet extending perpendicular to the c axis; the base-paired thymine molecules extrude alternately from the sheet. Diffused spots along c* with half integers of l can be interpreted as a stacking disorder of the sheets.
Temperature Effect on the Adsorption of Ionic Surfactants at Water/Hexane Interface from Micellar Solutions
Authors: Yamanaka Michio , Aratono Makoto , Iyota Hidemi , Motomura Kinsi , Matuura Ryohei
Published: July 2006

The adsorption behavior of dodecylammonium chloride (DAC) and sodium dodecyl sulfate (SDS) at their aqueous micellar solution/hexane interface has been studied by measuring the interfacial tension as a function of temperature at concentrations around the critical micelle concentration (cmc). The derivative of the interfacial tension with respect to temperature has been observed to change abruptly at the cmc and very little thereafter with increasing concentration in a limited range above the cmc. By applying the thermodynamic treatment of adsorption from micellar solution developed previously to the present experimental results, the entropy changes associated with the adsorption of DAC and SDS from monomeric state and from micellar state and the corresponding energy changes have been calculated. Further, the entropy and energy changes of micelle formation have been obtained from these quantity changes. These values have been compared with those obtained for DAC at water/air interface. It has been observed that the behavior of the micelle in the limited concentration range is controlled solely by temperature and pressure and bears resemblance to that of the adsorbed film at the interface. It has also been observed that the entropy and energy of micelle and adsorbed film are lowered by the hexane existing in the system.
Photon Echo of Pentacene Molecules Introduced in Crystals with High Concentration
Authors: Yoshikuni Yuzo , Nakamura Arao , Shionoya Shigeo
Published: July 2006

Photon echo decay time is measured for pentacence molecules introduced in naphthalene and p-terphenyl crystals with rather high concentrations (10−6–105 mol/mol) at temperatures between 1.6 K and 4.1 K, using a tunable picosecond laser system consisting of a mode-locked YAG laser and a parametric oscillator. In naphthalene echo decay time increases with lowering temperature approaching a constant value below 2 K, but in p-terphenyl it is almost constant. The phase relaxation time at very low temperature is much shorter than twice the population relaxation time in both crystals, indicating that pure dephasing processes exist. Analyzing the results it turns out that there exsists a pure dephasing process which is temperature-independent and is very probably due to interactions between pentacene molecules, in addition to the temperature-dependent dephasing process due to the scattering of pseudolocalized phonons.
The Dehydrogenation of Cyclohexane by the Use of a Porous-glass Reactor
Authors: Shinji Osamu , Misono Makoto , Yoneda Yukio
Published: July 2006

The dehydrogenation of cyclohexane was studied by the use of a double tubular reactor; the inner tube was made of porous glass, and the outer tube, of non-porous glass. The Pt/Al2O3 catalyst was placed inside the inner tube. It was demonstrated that dehydrogenation proceeded beyond the equilibrium conversion to be expected in the absence of a porous tube, by separating the hydrogen produced from the central reaction zone through the porous tube. When the reaction rate was so high that the reactant gas reached equilibrium near the inlet of the reactor, the dehydrogenation conversion became greater (more than twice the equilibrium conversion) as the flow rate in the inner path decreased and the flow rate in the outer path increased. The experimental data obtained by using the porous reactor were well reproduced by a computer simulation based on a simple model, in which such parameters as the flow rate, the gas permeability, and the reaction rate, were considered. The potential application of the present porous-reactor system was also discussed.
A Displaced Harmonic Oscillator Model for the Time-resolved Emission Spectra
Authors: Fujimura Yuichi , Sato Kenji , Nakajima Takeshi
Published: July 2006

In a displaced harmonic oscillator model for an energy-accepting mode, analytical expressions for the time-resolved emission intensity distribution are derived for both the allowed and vibronically induced electronic transitions. In the case of the vibronically induced transition, the inducing mode as well as the accepting mode is assumed to undergo a collisional vibrational relaxation. A linear vibrational quantum-number-dependence of the electronic and collisional vibrational relaxation constants is assumed. Model calculations of the time-resolved emission-intensity distribution for a molecular system are performed using the expressions derived. The calculated time-resolved emission spectra of benzene in the vapor phase after an excitation to a single vibronic level semi-quantitatively account for the experimental results.
Laser Flash Photolysis of Benzene. IV. Physicochemical Properties of Mist Produced by Laser Excitation
Authors: Nakashima Nobuaki , Yoshihara Keitaro
Published: July 2006

Mist formation is observed when gaseous benzene (8–75 Torr) (1 Torr=133.322 Pa) with oxygen (\lesssim10−5–860 Torr) is irradiated by a KrF excimer laser. By measuring the falling speed, the size of droplets in the mist is determined to be 2 to 6 μm depending on gas pressure. The number of droplets produced by irradiation with a 100 mJ/cm2 pulse is estimated to be 1×105/cm3 by measuring the benzene pressure change and by turbidity measurement. The disappearance yield of benzene is 0.1 and phenol is identified with a quantum yield of 0.01. The nucleus is produced by two-photon excitation of benzene and allowed to grow into mist through a subsequent oxidation and/or polymerization reaction.
One-photon and Two-photon Electronic Spectra of Two Caged Amines
Authors: Gonohe Narishi , Yatsuda Norio , Mikami Naohiko , Ito Mitsuo
Published: July 2006

The one-photon fluorescence excitation and two-photon resonant multiphoton ionization spectra of the S1←S0 transition of 1,4-diazabicyclo[2.2.2]octane (DABCO) in a supersonic free jet have been obtained and analyzed. It was found from the vibrational analysis that the S1←S0 transition is one-photon forbidden, two-photon allowed and the one-photon absorption appears by the vibronic interaction between the S1 and S2 states through the e′ vibrations. In addition, from the fluorescence spectrum and the polarization studies of the two-photon spectrum using the two linearly polarized laser beams of different wavelengths, it was concluded that the S1 state is 1A1′. The sequence structure involving the low-frequency cage torsional vibration has been observed in the two-photon resonant multiphoton ionization spectra of DABCO and 1-azabicyclo[2.2.2]octane (ABCO). The potential functions with respect to the torsional motion for both ground and excited states have been determined by utilizing the observed vibrational levels. It was found that the torsional potential has a broad minimum near the D3h (for DABCO) and C3V (for ABCO) conformations.
Effect of 1,4-Dioxane on the Structure of Aqueous t-Butyl Alcohol. Sound Velocity Studies
Authors: Manohara Murthy Neriyanuri , Subrahmanyam Saraswatula Venkata
Published: July 2006

The structure of aqueous t-butyl alcohol in the water rich region is known to be more structured than pure water. 1,4-dioxane is known to be a weakly hydrophobic solute. The effect of 1,4-dioxane on the structure of aqueous t-butyl alcohol has been studied by fixing the temperature of sound velocity maximum in the ternary solution from the experimentally determined ultrasonic velocity data at different temperatures. The structural contribution to the shift in the temperature of sound velocity maximum of the aqueous t-butyl alcohol solution due to the addition of 1,4-dioxane, [ΔTstr.]exptl, has been found to be positive having the nature of variation similar to that of the effect of 1,4-dioxane on pure water, when the concentration (Xs) of t-butyl alcohol is 0.0075. But, for aqueous t-butyl alcohol solutions having Xs=0.0025 and Xs=0.0046, [ΔTstr.]exptl, has been found to be negative reaching maximum values around X2=0.0045 and there after decreasing with a tendency to become positive at higher concentrations of 1,4-dioxane. These results have been explained in the light of structure breaking and formation of dioxane complexes in the ternary solutions.
Observation of Spin Sublevel Excitation Spectra. An Application to Vibrational Analysis of T←S Absorption
Authors: Suga Kazuhiko , Nishi Nobuyuki , Kinoshita Minoru
Published: July 2006

A new application of the T1←S0 excitation spectroscopy is presented by which absorptions to one or two of the three spin sublevels can be measured separately. This method has been applied to the T1←S0 excitation of crystalline 1,2,4,5-tetrachlorobenzene and 9H-xanthen-9-one at 1.4 K. The vibrational structures of the excitation spectra are analyzed in view of the spin selectivity observed.
Spectrophotometric Determination of Hexacyanoferrate(III) by Use of Coagulated Material Prepared from Finely Divided Anion and Cation Exchange Resins
Authors: Suzuki Kin-ya , Park Guee-deuk , Ohzeki Kunio , Kambara Tomihito
Published: July 2006

A simple and sensitive method for the determination of hexacyanoferrate(III) is described. This method is based on the preconcentration of hexacyanoferrate(III) ion on the coagulated material prepared from finely divided anion and cation exchange resins. The mixed resin is collected on a filter paper, forming a disk of thin layer. The hexacyanoferrate(III) fixed on the resin is converted to Turnbull’s Blue by treating with iron(II) ammonium sulfate solution. The colored compound in the resin phase is determined by a densitometer equipped with a linearizer. The working range is 0.4–3.0 μmol dm−3 hexacyanoferrate(III). Among cations likely to be present, only copper(II) interferes, however, the interference is removed by the addition of EDTA. Hexacyanoferrate(II) ion shows the same coloration as hexacyanoferrate(III), and the total amount is determined when both ions are present.
Nitrosyliron Complexes Containing 8-Quinolinolate or Its Derivatives
Authors: Miki Eiichi , Motonaga Masaaki , Mizumachi Kunihiko , Ishimori Tatsujiro , Katada Motomi
Published: July 2006

New nitrosyls, [Fe(C9H6NO)2(NO)]2(C9H6NO−=8-quinolinolate ion), [Fe(C10H8NO)(NO)2] (C10H8NO−=2-Methyl-8-quinolinolate ion), and [Fe(C9H5NOCl)2(NO)(DMF)] (C9H5NOCl−=5-chloro-8-quinolinolate ion) were isolated by the reaction of nitrogen monoxide with a mixture of iron(II) perchlorate and the corresponding quinolinol in methanol or methanol/DMF. They were characterized by IR, 57Fe-Mössbauer, and magnetic measurements.
Copper(II) Complex of 2,2′-Bi-8-quinolinol
Authors: Demura Youichi , Hirakawa Kazuyoshi , Murase Ichiro
Published: July 2006

A copper(II) complex of 2,2′-bi-8-quinolinol was prepared. The structure has been determined by means of infrared and electronic spectra, magnetic susceptibility under temperature variation, and molecular weight measurement. It was found to be a binuclear chelate having a tetrahedral arrangement around each copper ion.
Studies of the Cobalt(III) Complexes of 8-Amino-3,6-diazaoctanate Ion. IV. Preparations and Some Properties of [Co(ADAO)XY] Type Complexes: XY=Cl(NH3), Cl(py), (H2O)(py), Cl(H2O), (NO2)(H2O), and Cl(NO2)
Authors: Watanabe Kiyokatsu
Published: July 2006

The following new cobalt(III) complexes containing the 8-amino-3,6-diazaoctanate ion (adao) have been isolated: two isomers of β-mer(N)-trans(Cl,Oada)-[Co(adao)(Cl)(NH3)]ClO4, two isomers of β-mer(N)-trans(Cl, Oadao)-[Co(adao)(Cl)(py)]ClO4, β-mer(N)-trans(O)-Co(adao)(H2O)(py)]ClO4·bcs, β-mer-(N)-trans(Cl,Oadao)-[Co(adao)(Cl)(H2O)]CLO4, β-fac(N)-[Co(adao)(Cl)(H2O)]ClO4, β-mer(N)-cis(O)-[Co(adao)(NO2)(H2O)]ClO4, and β-fac(N)-[Co(adao)(Cl)(NO2)]. The geometrical structures have been determined on the basis of the absorption spectra, the proton NMR spectra, and the consideration of their preparative processes.
Oxidative Synthesis, Optical Resolution, and Characterization of Mixed Sulfenato and Sulfinato Cobalt(III) Complexes
Authors: Kita Masakazu , Yamanari Kazuaki , Shimura Yoichi
Published: July 2006

Twelve new mixed sulfenato and sulfinato cobalt(III) complexes were prepared via successive H2O2 oxidation of [Co(SCH2CH2NH2)3], [Co{SCH2CH(COOCH3)NH2}3], and related complexes. These oxidation products, [Co(sulfenato-N,S)n(sulfinato-N,S)3−n] (n=3, 2, 1, and 0), were optically resolved by means of column chromatography or preferential crystallization of a diastereomeric molecular compound with d-tartaric acid. The mixed sulfenato and sulfinato complexes show characteristic variation of absorption spectra with the change of “n” in [Co(sulfenato-N,S)n(sulfinato-N,S)3−n] (n=3, 2, 1, and 0). It is concluded that the (R) configuration of the sulfenato group is more stable than the (S) one in the fac(S)-Λ-[Co(sulfenato-N,S)n(sulfinato-N,S)3−n].
Electron Transfer Activation in the Oxidative Addition of Iodine to Rhodium(I) Complexes
Authors: Fukuzumi Shunichi , Nishizawa Nobuaki , Tanaka Toshio
Published: July 2006

The kinetics of the oxidative addition of iodine to the following isocyaniderhodium(I) monomers and dimers in MeCN has been examined; [Rh(RNC)4]+, [Rh(RNC)2(PPh3)2]+, [Rh2(dppm)2(RNC)4]2+, and [Rh2(dicp)4]2+ (R=alkyl, aryl; dppm=bis(diphenylphosphino)methane; dicp=1,3-diisocyanopropane). The reaction proceeds via two consecutive steps which consist of the formation of the initial adduct followed by the intramolecular isomerization to yield the final trans-adduct. The kinetic results for the first step of the oxidative addition reactions suggest that there exist three kinds of intermediates formed between the Rh(I) complex and iodine with 1:1, 1:2, and 2:1 stoichiometry prior to the formation of the initial adduct. This mechanism coincides with that for the electron transfer reactions between the Rh(I) complexes and inorganic oxidants such as [Fe(N-N)3]3+ (N-N=1,10-phenanthroline and 2,2′-bipyridine). The values of the rate constants for the first step of the oxidative addition of iodine to dppm- or dicp-bridged Rh(I) dimers are found to agree with those for the electron transfer reactions between the same reactants by using linear free energy relationships. The possibility of electron transfer activation as the rate determining step in the oxidative addition to Rh(I) complexes is discussed.
Cyclic Voltammetry of Rh(I) Complexes and the Oligomers. A Correlation between the Anodic Peak Potentials and the Rate Constants for the Electron Transfer Reactions with Inorganic Oxidants
Authors: Fukuzumi Shunichi , Nishizawa Nobuaki , Tanaka Toshio
Published: July 2006

The cyclic voltammogram of a CH3CN solution of [Rh(p-MeOC6H4NC)4]+ exhibits three anodic current peaks which correspond to the oxidations of the monomer, the dimer, and the trimer, with no cathodic wave on the reverse scan. The anodic peak potentials Eoxp in such irreversible cyclic voltammograms were determined for various Rh(I) monomers and the oligomers such as [Rh(RNC)4]+, [Rh2(RNC)8]2+, [Rh2(dppm)2(RNC)4]2+, [Rh2(dicp)4]2+, [Rh3(RNC)12]3+, and [Rh4(dicp)8]4+ (R=p-MeOC6H4 and Ph, etc; dppm=bis(diphenylphosphino)methane, dicp=1,3-diisocyanopropane). The anodic peak potentials Eoxp vary mainly with the degree of oligomerization of the Rh(I) complexes, decreasing in the order monomer>dimer>trimer>tetramer, in parallel with the energies of the highest occupied molecular orbitals EHOMO. It has been found that the Eoxp values are linearly correlated with logarithm of the rate constants for the electron transfer reactions with inorganic oxidants such as [Fe(bpy)3]3+ and [Co(bpy)3]3+ (bpy=2,2′-bipyridine) in the context of the Marcus theory as expected when the standard oxidation potentials Eoxo would be used. It is thus suggested that the anodic peak potentials of the Rh(I) complexes in the irreversible system can be used as the standard oxidation potentials as far as the relative values are concerned.
The Structure and Synthesis of Sudachiin A, a New Flavone Glucoside from Citrus Sudachi
Authors: Horie Tokunaru , Tsukayama Masao , Nakayama Mitsuru
Published: July 2006

Sudachiin A was isolated from the green peels of Citrus sudachi Hort. ex Shirai. This structure was deduced to be sudachitin 4′-β-d-glucoside by means of its spectra and degradation; this was confirmed by the synthesis of the one from sudachitin 7-benzyl ether and α-acetobromoglucose via several steps. 4′,5,7-Trihydroxy-3′,6,8-trimethoxyflavone 7-glucoside (sudachitin 7-β-d-glucoside), which was isolated from Sideritis leucantha Cavanilles, was also synthesized from sudachitin and α-acetobromoglucose in a similar manner.
Studies of the Selective O-Alkylation and Dealkylation of Flavonoids. V. The Synthesis of 5,6-Dihydroxy-3,4′,8-trimethoxyflavone and a Revised Structure for the Flavone from Conyza stricta
Authors: Horie Tokunaru , Kourai Hiroki , Osaka Hideaki , Nakayama Mitsuru
Published: July 2006

5,6-Dihydroxy-3,4′,8-trimethoxyflavone, which was the proposed structure of the pigment occuring in Conyza stricta, was synthesized from 2,3,5,6-tetramethoxyacetophenone in six steps. The natural pigment was identical not with the synthesized flavone, but with 5,7-dihydroxy-3,4′,8-trimethoxyflavone, an isomer of the former.
Photoinduced Ring-opening Reaction of 1-(2-Naphthoyl)aziridine in Various Halogenated Hydrocarbons
Authors: Nishimoto Sei-ichi , Izukawa Tsukuru , Kagiya Tsutomu
Published: July 2006

The in-source photoreaction and the postreaction of 1-(2-naphthoyl)aziridine (NAz) in various halogenated hydrocarbons have been investigated at room temperature under deaerated conditions. Secondary amide such as N-(2-chloroethyl)-2-naphthamide (CENA) or N-(2-bromoethyl)-2-naphthamide (BENA) was obtained along with a rearranged product of 2-(2-naphthyl)-2-oxazoline (NOz). The initial rate of secondary amide formation increased with decreasing dissociation energy of the carbon–halogen bond of halogenated hydrocarbon. The yield of CENA in the postreaction was substantially equal to that of chloride ion formed via the photolyses of chlorinated hydrocarbons. The rearranged product of NOz was confirmed to undergo subsequently photochemical ring-opening reaction to afford CENA or BENA.
Studies on Chemical Synthesis of mRNAs. I. Synthesis and Properties of N2-Tritylguanosine Derivatives and Application to Synthesis of pGpUpU
Authors: Hata Tsujiaki , Gokita Noboru , Sakairi Nobuo , Yamaguchi Kazuo , Sekine Mitsuo , Ishido Yoshiharu
Published: July 2006

Trityl (Tr), 4-methoxytrityl (MMTr), and 4,4′-dimethoxytrityl (DMTr) groups were introduced into the 2-amino group of 2′,3′,5′-tri-O-acetylguanosine by treatment with the corresponding trityl chlorides in pyridine to afford the N2-tritylated guanosine derivatives in high yields. Similarly, the N6-tritylated adenosine derivatives were synthesized. The stability of the three kinds of trityl groups under acidic conditions were described. The MMTr and Tr groups were found to be suitable for the protection of the 2-amino group of guanosine in oligonucleotide synthesis. An appropriately protected N2-tritylguanosine 5 -phosphorodithioate derivative was synthesized and utilized for the synthesis of pGpUpU.
Thermodynamic Properties for the Adduct Formation of Some Shift Reagents with Aniline
Authors: Kojima Hideo , Nonaka Hiroshi , Hirota Minoru
Published: July 2006

Equilibrium constants, enthalpies, and entropies of formation of the shift reagent-substrate adducts were determined by the measurement of infrared spectra. Aniline was employed as substrate in most cases since its NH stretching absorption bands (νas) does not overlap with those of the adducts and suitable to estimate the amount of its free species quantitatively. A series of Ln(dpm)3 and Ln(fod)3 (where Ln=Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, and Yb) were used as shift reagents. The formation constants (K1 and K2), as well as ΔH, decrease in the increasing order of the atomic numbers of the central lanthanoid ions. The results were compared with those on some bis(β-diketonato) complexes of transition metal ions and discussed.
Stereoselective α-Glucosylation with Tetra-O-benzyl-α-d-glucose and a Mixture of Trimethylsilyl Bromide, Cobalt(II) Bromide, Tetrabutylammonium Bromide, and a Molecular Sieve. A Synthesis of 3,6-Di-O-(α-d-glucopyranosyl)-d-glucose
Authors: Koto Shinkiti , Morishima Naohiko , Kusuhara Chiharu , Sekido Shigeko , Yoshida Toyosaku , Zen Shonosuke
Published: July 2006

A mixture of trimethylsilyl bromide, cobalt(II) bromide, tetrabutylammonium bromide, and a molecular sieve (4A) is effective for the stereoselective, one-stage α-glucosylation of alcohol with 2,3,4,6-tetra-O-benzyl-α-d-glucopyranose in dichloromethane. Using this procedure, several disaccharide derivatives as well as O-α-d-glucopyranosyl-(1→3)]-O-[α-d-glucopyranosyl-(1→6)]-d-glucopyranose are synthesized.
The Separation of Cobalt(II), Copper(II), Zinc(II), Lead(II), and Cadmium(II) as Their 3-Methyl-1-phenyl-4-thiobenzoyl-5-pyrazolone (SBMPP) Chelates by Thin-layer Chromatography on Silica Gel
Authors: Chouhan V S , Rao G N
Published: July 2006

Thin-layer chromatographic separation technique has been employed for the separation of Co(II), Ni(II), Cu(II), Zn(II), Pb(II), and Cd(II) as their 3-methyl-1-phenyl-4-thiobenzoyl-5-pyrazolone (SBMPP) chelates. Metal chelates are intensely coloured and so no additional reagent was needed for the development of spots. Silica gel G was used as an adsorbent in the form of thin layer coating (0.25 mm) on glass plates (5 cm × 20 cm). The Rf values of SBMPP and metal–SBMPP chelates have been determined by the ascending method with pure solvents and various binary solvent mixtures on thin layer of silica gel. In benzene the order of Rf values is Cd(II)<Pb(II)<Zn(II)<Co(II)<SBMPP<Ni(II)=Cu(II). By employing solvents like dichloromethane, benzene, and toluene, mutual separation of metal complexes was achieved successfully. The mixed solvents are more useful for the mutual separation of chelates than the pure solvents.
Effect of Conformation on Ring Opening of Cis and Trans Dimers of Acenaphthylene in the Triplet State. Direct Detection of Hydrocarbon Biradical, 1,1′-Biacenaphthene-2,2′-diyl
Authors: Kobashi Harumichi , Ikawa Hiroki , Kondo Reiko , Morita Toshifumi
Published: July 2006

Triplet sensitized photodecomposition of cis and trans dimers of acenaphthylene (c-D and t-D) has been studied in benzene by means of a nanosecond laser flash photolysis. An aromatic hydrocarbon biradical, 1,1′-biacenaphthene-2,2′-diyl (1) was found as an intermediate for the decomposition of triplet t-D to acenaphthylene monomers. The rate of bond opening was directly measured to be 8.3×106 s−1 at 20 °C. The temperature dependence of the rate yields the frequency factor 2.8×107 s−1 and activation energy 3.1 kJ mol−1. The lifetime of 1 is 330 ns; this is insensitive to temperature changes (6–64 °C). Oxygen quenches 1 with the rate constant of 9×109 M−1 s−1 (1 M=1 mol dm−3). On the other hand, the triplet state of c-D did not show any evidence of the presence of 1 as an intermediate. The difference of ring opening mechanisms between the two isomers is interpreted in terms of different steric hindrances between two acenaphthene rings. The triplet-triplet (T-T) absorption spectra of both dimers resemble each other. No characteristic absorption due to intramolecular triplet excimer of naphthalene was observed even for c-D.
A New Synthesis of (Z)-13-Eicosen-10-one and (Z)-12-Nonadecen-9-one, the Pheromones of Peach Fruit Moth
Authors: Yoshida Takashi , Saito Shojiro
Published: July 2006

(Z)-13-Eicosen-10-one and (Z)-12-nonadecen-9-one were easily synthesized from starting 1-(p-tolysulfonyl)nonane and 1-(p-tolylsulfonyl)octane via 4 steps, respectively.
Studies on 2-Aziridinecarboxylic Acid. VI. Synthesis of β-Alkoxy-α-Amino Acids via Ring-opening Reaction of Aziridine
Authors: Nakajima Kiichiro , Neya Masahiro , Yamada Shinichi , Okawa Kenji
Published: July 2006

The reaction of aziridine derivatives having a urethane-type protecting group with several alcohols in the presence of boron trifluoride etherate afford the corresponding optically pure O-alkylserine and O-alkylthreonine derivatives via a ring-opening reaction of aziridine in good yield.
Radiation-induced Alkylation, Hydroxyalkylation, and Reduction of Pyridinecarboxamides in Acidic Alcoholic Solutions
Authors: Sugimori Akira , Nishijima Masayuki , Itoh Hiroshi
Published: July 2006

The γ-irradiation of pyridinecarboxamides in acidic methanol or ethanol brings about substitution of the ring hydrogen by alkyl or hydroxyalkyl groups derived from the solvent alcohols in relatively high G-values. In 2-propanol, little alkylation and hydroxyalkylation occur and reduction of CONH2 to CH2OH occurs in low G-values.
Study on the Reaction of Monofunctional Fluorescent Reagents in Organic Solutions by Fluorometry
Authors: Okamoto Akio , Uchiyama Katsumi , Mita Itaru
Published: July 2006

Rections of some fluorescent reagents with substrates, used widely in biochemistry for quantitative analysis of some functional groups in aqueous media, have been studied in organic solutions with a view that they may be used also in the area of synthetic polymer science. Reactions studied by fluorometry were (i) 5-dimethylamino-1-naphthalensulfonyl chloride with butylamine, (ii) 2-naphthalenesulfonyl chloride with butylamine, and (iii) N-(1-naphthyl)maleimide with 1-pentanethiol. In polar solvents all the fluorescent probes studied are too labile and converted spontaneously into fluorescent compounds. In less polar solvents, however, such side reactions do not take place and the reaction of fluorescent reagents with substrates proceeds quantitatively with a simple second-order kinetics. The second-order rate constants for the three reactions are of the order of 10−3 to 10−1 M−1 s−1 in the range of about 30 to 50 °C, and they increase with the solvent polarity.
A Molybdenum Polynuclear Complex as Small Metallic Particles
Authors: Okumura Hajime , Taga Tooru , Osaki Kenji , Tsujikawa Ikuji
Published: July 2006

The crystal structure of (H3O)2[(Mo6Cl8)Cl6]·6H2O was determined by the X-ray method and its near-infrared absorption spectra were measured. These results can be interpreted by a view that the molybdenum nuclei of this complex are regarded as a small metallic particle.
Despretz Constants for Individual Ions
Authors: Wakabayashi Toshiki , Takaizumi Katsuko
Published: July 2006

The shifts (ΔT) in the temperature of maximum density (tmd) of water produced by electrolytes have been revised. It was found that the temperature dependences of Sv and/or by bv coefficients in the Redlich-Meyer equation should be taken into account, to obtain exactly the Despretz constants (KD) or the standard partial molal expansibility (\barE°) from tmd data. The KD’s for 1 : 1 electrolytes were divided into the ionic components (KD,i), by applying the value for \barEi° (H+, 4 °C). Of the familiar monovalent ions, the KD,i values are negative (ΔT>0) only for H+ and Li+ ions and are positive for all the anions examined, including F− ion. A further attempt was made to extract from KD,i’s for organic ions the structural part Kst,i’s, based on a model. The Kst,i’s seem to reflect the structure-influencing ability of organic ions, but may not always be the case.
Spectroscopic Study of 10-Benzoyl-9-anthrol and Its Anion in Basic Media. An Estimation of Microscopic Polarity of PMMA
Authors: Hamanoue Kumao , Hirayama Satoshi , Amano Masayuki , Nakajima Kazuo , Nakayama Toshihiro , Teranishi Hiroshi
Published: July 2006

The acid-base equilibrium of the title compound (BAOH) was studied in various media containing 4% triethylamine (TEA) by volume as a base. As the polarity of solvents increases, the equilibrium shifts toward the base form (BAO−) and 100% yield of BAO− is achieved in solvents with dielectric constant (ε) greater than 20. The equilibrium is also affected by temperature, favoring the base form at lower temperatures. The associated enthalpy change is estimated to be −14.6 kJ mol−1. Of particular interest is the dominant existence of BAO− in poly(methyl methacrylate) (PMMA), since the acid form (BAOH) dominates in a monomeric solvent (MMA). The microscopic effective dielectric constant of PMMA is estimated to correspond to that of a solvent with ε=22–30 by comparing spectral data in PMMA with those in various solvents. No base form is formed in polystyrene, indicating that not only rigidity but also polar groups in PMMA may be responsible for the anomalously large dielectric constant of PMMA.
Macromolecular Ion Flotation of Fe3+, Cu2+, and Ni2+ Ions by Combined Use of Macromolecular Anions and Cationic Surfactant
Authors: Sasaki Tsunetaka , Kud\={o} Takashi , Machida Ikuko , Ishiwata Satoshi
Published: July 2006

Macromolecular ion flotation of Fe3+, Cu2+, and Ni2+ ions was studied using macromolecular ions such as sodium metasilicate, sodium polyacrylate, sodium carboxymethylcellulose, sodium alginate, and sodium cyclo-hexaphosphate (SCHP) together with hexadecyltrimethylammonium chloride (HTAC). Diagrams of floatability vs. composition of macromolecular ion and HTAC, and floatability vs. pH at fixed composition of macromolecular ions and HTAC were constructed. Regions of optimum composition and pH for the flotation were determined and tabulated. Maximum floatabilities greater than 95%, some attaining nearly 100%, in the alkaline region were obtained for most of the systems, except for the system Fe3+–SCHP–HTAC which showed its maximum floatability, 91.7%, in the acid region. Metallic ions are considered to be combined as hydroxides with macromolecules which are then floated.
The Effect of Added NaCl on the Binding of Sodium Perfluorooctanoate to Lysozyme in Aqueous Solutions
Authors: Fukushima Kohsuke , Sugihara Gohsuke , Murata Yoshio , Tanaka Mitsuru
Published: July 2006

The binding isotherms of sodium perfluorooctanoate (SPFO) to lysozyme have been investigated as a function of added NaCl by a potentiometric method utilizing a perfluorooctanoate ion selective electrode. The general feature of the binding of SPFO to lysozyme resembled that of sodium dodecyl sulfate. Although the lysozyme–SPFO system is different in detail from that of lysozyme–sodium dodecyl sulfate system, resulting from the mutual phobicity and the difference in hydrophobicity, the binding mechanism proposed for lysozyme–sodium dodecyl sulfate system can be true also for the binding of SPFO to lysozyme.
Multiatomic Ion Model for Interdiffusion in the System Na2O–CaO–SiO2
Authors: Nanba Masao , Oishi Yasumichi , Wakabayashi Hajimu
Published: July 2006

Concentration distributions after interdiffusion at 1200 °C were analysed for the diffusion couple of average composition 16Na2O·12CaO·72SiO2 (wt%) in terms of self-diffusion coefficients of constituent elements. Theoretical calculation was conducted using a multiatomic ion model assuming that Si migrates with oxygens as a silicate ion. The composition of the silicate ion was estimated by determining the parameters in the diffusion equation so as to provide the best fit of the theoretical calculations to the experimental concentration profiles.