bluuebunny/crossref_metadata_2025 huggingface dataset:
Preparation, Stability, and Compositions of the Crystals of Reduced Riboflavins
Authors: Ebitani Matsue , Kashiwagi Hiroshi , Inoue Masami , Nishibe Keiichi
Published: July 2006

Green crystals were obtained after a reduction of riboflavin (RF) with Na2S2O4. These crystals were gradually oxidized to RF when stored in air, even at −10°C. The emission spectra and X-ray powder diffraction analyses of the green crystals clearly showed different patterns from those of RF. The ESR spectra and number of the reduced species determined by the titration with KMnO4 supported the formation of an RF-flavosemiquinone radical (1 : 1) complex. Reduced riboflavin tetrabutyrate prepared according to the same procedure was too unstable for dioxygen to obtain spectroscopic data.
Reactions of α,β-Unsaturated Ketone Acetals with Trimethylsilyl Cyanide and Trimethylsilyl Sulfides
Authors: Soga Tsunehiko , Takenoshita Haruhiro , Yamada Masaaki , Han Jeng S , Mukaiyama Teruaki
Published: July 2006

In the presence of a catalytic amount of trityl perchlorate, trimethylsilyl cyanide reacts with the dimethyl acetals of chalcone derivatives, with simultaneous double bond isomerization, to yield γ-methoxy-α,β-unsaturated carbonitriles. Trimethylsilyl sulfides react with dimethyl acetals derived from α,β-unsaturated ketones to yield 1,3-bis(alkylthio)propene derivatives under similar conditions.
Oxygen Effect on Photocatalytic Reaction of Ethanol over Some Titanium Dioxide Photocatalysts
Authors: Iseda Kozo
Published: July 2006

The suspensions of four kinds of TiO2 photocatalysts in ethanol have been studied under ultraviolet light in an atmosphere of Ar, air, or O2 at 25°C. The main products were acetaldehyde, acetaldehyde diethyl acetal (acetal), acetic acid, water, ethylene, methane, carbon dioxide, and hydrogen. Acetaldehyde and acetal were abundantly produced in all of the products. The formation of all of the products under O2 was more efficient than those under Ar and air. The photochemical activity of each TiO2 is stronger than that of either Ti2O3 or TiO.
Redox Potential of Fe4S4 Cluster in Hydrophobic and Hydrophilic Spheres
Authors: Tanaka Koji , Tanaka Satoshi
Published: July 2006

The redox behavior of the [Fe4S4(SC6H4But(p-))4]2−⁄3− couple was examined not only in a CH2Cl2 solution of a CH2Cl2/H2O two phase system but also in the absence and presence of Triton X-100 in H2O to elucidate the solvent effect of water on the redox potential of the cluster. Protonation of [Fe4S4(SC6H4But(p-))4]3− takes place in those media, and protonated and unprotonated clusters exist as an equilibrium mixture. Although the redox potential of the cluster is hardly affected by the pKa value, it is largely influenced by a thickness of [Fe4S4(SC6H4But(p-))4]2− adsorbed on a surface of an electrode in water. The E1⁄2 value of the cluster in a near monomolecular layer on the electrode exhibits a pronounced anodic shift compared with that in CH2Cl2 and falls in the range of that of 4Fe- and 8Fe-ferredoxins. On the other hand, the cluster in the multimolecular layer does not show such an anodic shift of the E1⁄2 value in water.
Solvation and Ionic Association of (1R,4S,8R,11S)-1,4,8,11-Tetramethyl-1,4,8,11-tetraazacyclotetradecanenickel(II) Perchlorate in Mixed Solvents of N,N-Dimethylformamide and N,N-Dimethylacetamide with Nitrobenzene and 1,2-Dichloroethane
Authors: Yokoyama Takashi , Iwamoto Etsuro , Kumamaru Takahiro
Published: July 2006

The conductances of [NiL]2+ ([NiL]2+=(1R,4S,8R,11S)-1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecanenickel(II)) have been measured in N,N-dimethylformamide (DMF)–1,2-dichloroethane (DCE), and N,N-dimethylacetamide (DMA)–DCE, and iso-relative permittivity mixtures DMF–nitrobenzene (NB), DMA–NB, and DMF–DMA at 25°C. The first ionic association constant of [NiL]2+ with the perchlorate ion in the mixtures with NB decreases with increasing fraction of both DMF and DMA, although DMF is coordinated to [NiL]2+ and DMA is not, this showing that DMA as well as DMF in NB selectively solvates the axial coordination site of [NiL]2+ to change from contact ion pairs to solvent-separated ion pairs. Bulky and delocalized negative pole of NB of which the dipole moment is larger than that of DMF and DMA results in a weak ion–dipole interaction, leading to a larger degree of ionic association. Ionic association was discussed from the viewpoint of steric hindrance and ion–dipole interactions.
Synthesis of Strapped, Dimeric, and Trimeric Porphyrins Based on Intramolecular Macrocyclization Reactions
Authors: Osuka Atsuhiro , Kobayashi Fumikazu , Maruyama Kazuhiro
Published: July 2006

Strapped porphyrins were prepared directly by the acid-catalyzed condensation reaction of 3,3′-diethyl-4,4′-dimethyl-2,2′-dipyrrylmethane and methylenedioxy bridged dialdehydes having a strap linkage longer than 7 atoms. Dimeric and trimeric porphyrins with coplanar and orthogonal (T-shape) geometries were also synthesized in good yields as an application of this method. In the strapped porphyrins, the distortion of porphyrin ring increases systematically on shortening the strap linkage, which is confirmed by their 1H NMR data, red shifted absorption, and fluorescence spectra. In the coplanar dimeric and trimeric porphyrins, the electronic interactions between the porphyrins were distinctly observed, while in the orthogonal “T-shaped” dimers and “H-shaped” trimers, appreciable electronic interactions were not observed.
Polymerization Mechanism of Styrene Initiated by 2,2-Bis(t-butyldioxy)alkanes
Authors: Watanabe Yasumasa , Ishigaki Hideyo , Okada Hiroshi , Suyama Shuji
Published: July 2006

The radical polymerization mechanism of styrene initiated by 2,2-bis(t-butyldioxy)alkanes (1) has been studied in benzene. The decomposition products of 1 are acetone, alkyl methyl ketone, t-butyl alcohol, and t-butyl peracetate. Styrene monomer converts to polystyrene along with styrene oxide. The peroxides 1 cleave homolytically at one of dioxy bonds to yield intermediate alkoxyl radicals with α-t-butyldioxyl group, which undergo β-scission to afford t-butyldioxyl or alkyl radicals. The resulting t-butyldioxyl radical reacts with styrene to form 2-(t-butyldioxy)-l-phenylethyl radical, which decomposes subsequently to styrene oxide and t-butoxyl radical via γ-scission. Alternatively, a part of t-butyldioxyl radical adds to styrene to afford polystyrene containing dioxy bond.
Effect of a Hydrogen Pretreatment on the Mechanism of Deuterium Addition and Exchange of Propene over Ni–Cu Alloy Catalysts
Authors: Naito Shuichi , Tanimoto Mitsutoshi
Published: July 2006

The effects of a hydrogen pretreatment on the activity and reaction intermediate in a C3H6–D2 reaction over a Ni–Cu alloy as well as Ni metal catalysts were investigated in detail by applying an isotope tracer technique. Ni metal and Ni-rich alloy catalysts, cooled down to the reaction temperature under a hydrogen atmosphere (D-surface), exhibited low activity compared to that of a surface evacuated before cooling (E-surface). For Cu-rich alloy catalysts, however, the E-surface exhibited a lower activity and a higher activation energy than did the D-surface. A comparison of the TPD spectra of adsorbed hydrogen with the dependence of the activity upon the evacuation temperature suggests that strongly adsorbed hydrogen retards the reaction over Ni and Ni-rich alloy catalysts at lower temperature. Microwave spectroscopic analysis demonstrated that the reaction intermediates over D- and E-surfaces of Cu-rich alloy catalysts were similar to those over Cu and Ni metals, respectively. This result suggests that a hydrogen pretreatment of Cu-rich alloys forms a specific surface structure which is destroyed by evacuation at elevated temperatures.
Small-Angle X-Ray Scattering Study on Sol–Gel Transition of Mixtures of Colloidal Silica and Organic Polymer
Authors: Matsuoka Hideki , Chen Sheng-rong , Ishii Hiroshi , Ise Norio , Nakanishi Kazuki , Soga Naohiro
Published: July 2006

Sol–gel transition of mixtures of colloidal silica–water soluble organic polymer (sodium polystyrenesulfonate) has been investigated by the small-angle X-ray scattering technique. With proceeding gelation, an increase of the intensity at small-angle regions was observed and the values of radius of gyration (Rg) were estimated by the Guinier method. The addition of polymer increased the initial increase of Rg with gelation, i.e., sol–gel transition was accelerated by the presence of the polymer. This observation is not in contradiction to the prediction of micro-phase separation into silica-rich phase and polymer-rich phase proposed by Nakanishi and Soga. The fractal analyses predicted that the geometrical structure of the gel finally formed is similar to those of random coil linear polymer and swollen branched polymer.
Mössbauer Emission Study of Recoil 119Sb and 119mTe Atoms after Nuclear Decays and Reactions in SnS and SnSe
Authors: Ambe Shizuko , Ambe Fumitoshi
Published: July 2006

The chemical fates of 119Sb and 119mTe recoil atoms after p- and α-reactions in SnS and SnSe were studied by Mössbauer emission spectroscopy. The 120SnS and 120SnSe samples irradiated with protons gave a partly resolved asymmetric doublet ascribable to 119Sn at the Sn site of the matrices. The α-irradiated 117SnS and 117SnSe samples gave emission spectra, drastically different from those of p-irradiated 120SnS and 120SnSe as well as that of α-irradiated 120SnTe. The spectra are decomposable into three lines which are hardly assignable to any known chemical species of Sn and S or Se. Two of the lines are assigned to a doublet of divalent 119Sn in the Sn site of SnS or SnSe with a nearby defect on the basis of their behavior on thermal annealing. The other line is ascribed to tetravalent 119Sn in a defect structure.
Dynamical Characterization in Aqueous Solutions of 3-Methoxy-and 3-Ethoxy-1-propanol by Ultrasonic Methods
Authors: Nishikawa Sadakatsu , Ueda Masayuki
Published: July 2006

3-Methoxy-1-propanol and 3-ethoxy-1-propanol were synthesized through potassium propoxide from 1,3-propanediol. Ultrasonic absorptions in their aqueous solutions were measured in the frequency range from 8.5 to 220 MHz as functions of their concentrations along with the sound velocity and density. In a solution of 3-ethoxy-1-propanol, a single relaxational absorption was observed; the cause was attributed to a perturbation of an equilibrium as AB ↔ A + B, where AB represents the solute-solvent complex, A the solute and B the solvent molecules. On the other hand, no relaxational absorption was observed in a 3-methoxy-1-propanol solution up to 4 mol dm−3. The thermodynamic and the kinetic parameters were evaluated for the above-mentioned process from the concentration dependences of the ultrasonic parameters in a 3-ethoxy-1-propanol solution. From evidence concerning the appearance and disappearance of ultrasonic relaxational absorption and comparisons of the rate and thermodynamic constants in aqueous solutions of various alcohols, the alternation of the water structure affected by the addition of the solutes is discussed in connection with the solute structures. The methoxyl group was explicitly found to act as a water structure breaker and the ethoxyl group to do so slightly.
Acidic Property of Rh and Ru Complexes
Authors: Kou Yuan , Yamada Nobuo , Akutagawa Susumu , Zhang Geng , Tanabe Kozo
Published: July 2006

The acidic property of [Rh(nbd)(dppb)]ClO4, [Ru(binap)](BF4)2, and [Ru(dmso)6](ClO4)2 was measured by using the acetalization of cyclohexanone as a test reaction and the temperature-programmed desorption [TPD] of pyridine. The acid strengths were estimated to be H0=−2.1 for [Ru(dmso)6](ClO4)2 and H0=−2.2 for [Ru(binap)](BF4)2 and [Rh(nbd)(dppb)]ClO4 by the test reaction method. The TPD method gave consistent results.
Synthesis and Properties of High Molecular Weight Polypeptides Containing of Tryptophan
Authors: Iizuka Yasuko , Endo Toshiya , Oya Masanao
Published: July 2006

High purity N-carboxy-Dl-tryptophan anhydride (Dl-4-indoylmethyl-2,5-oxazolidinedione, Dl-Trp NCA) was synthesized in good yield. Copolypeptides with a random sequence of Dl-Trp with l-alanine (Ala) and Dl-alanine (Dl-Ala) were synthesized by copolymerization of the corresponding N-carboxy-α-amino acid anhydrides (NCA) in solution. Copolypeptides of Dl-Trp with l-Ala and Dl-Ala were partially soluble in water. The water-soluble copolypeptides of Dl-Trp and l-Ala mostly gave disordered conformations, while the water-insoluble copolypeptides were found in a mixture of α- and disordered conformations. The solubility of the copolypeptides was not influence by the tryptophan content in the polypeptides but, rather, by the conformation of the polypeptides.
Formation of Small Cobalt Clusters from CoNaY by Reduction with H2 and Consecutive H2–O2 Treatments
Authors: Kim Jae C , Woo Seong I
Published: July 2006

In order to raise the degree of reduction and promote the formation of zerovalent cobalt clusters, repetitive treatments of CoNaY with hydrogen and oxygen were carried out. The intensity of FMR (ferromagnetic resonance) band of CoNaY reduced for 36 h at 773 K with intermittent oxygen treatments was twice as much as that of CoNaY reduced only with hydrogen. This fact meant that reduction of CoNaY with H2–O2 treatments favored to produce zerovalent cluster due to the increase in the mobility of Co2+ ions in CoNaY. The size of clusters is so small that such conventional methods as hydrogen chemisorption, X-ray diffraction, and TEM can not detect the quantity of zerovalent cobalt clusters. FMR spectroscopy, H2-consumption measurement, and catalytic probe reaction method were used to measure the degree of reduction and were correlated well with one another.
Reaction between Nitrogen Monoxide and Carbon Monoxide over Superconducting Bi–Sr–Ca–Cu and Related Mixed Oxides
Authors: Mizuno Noritaka , Toyama Hisashi , Tanaka Mika , Yamato Mika , Misono Makoto
Published: July 2006

Bi–Sr–Ca–Cu–O mixed oxides having a Bi2Sr2CaCu2Oy structure were very active for reactions between nitrogen monoxide and carbon monoxide among the prepared catalysts having perovskite and related structures.
Cobalt(IV) Amine Complexes with Organic Ligands. XI. The Preparation and Properties of Tetraammine(7-chloro-5-nitro- or 5,7-dinitro-8-quinolinolato)cobalt(IV) Complexes and the Corresponding Cobalt(III) Complexes
Authors: Yamamoto Yoshihisa , Toyota Eiko , Konno Hidetaka
Published: July 2006

Tetraammine(7-chloro-5-nitro- or 5,7-dinitro-8-quinolinolato)cobalt(IV) complexes and the corresponding cobalt(III) complexes have been isolated, and characterized by analytical, spectroscopic, magnetic, and XPS methods. The effective magnetic moments of cobalt(IV) complexes were ca. 1.6 BM, suggesting an unpaired spin. An unpaired spin on the complex is located over the π-orbitals of the 7-chloro-5-nitro- or 5,7-dinitro-8-quinolinolato ligand (abbreviation: chelated ligand) and on the cobalt atom from the results of the C 1s and Co 2p spectra by XPS. The Cl 2p binding energy of the chloride ion suggests that the valence electrons of the chloride ions may have some interaction with the π-orbitals of the chelated ligand.
Cyclotriveratrylene Crown Ethers: Metal Ion Extraction and Transport Abilities through Organic Membrane
Authors: Akabori Sadatoshi , Takeda Masakazu , Kawakami Hiroshi
Published: July 2006

Extraction abilities of cyclotriveratrylene crown ethers (2) toward alkali, alkaline earth, and other metal ions were examined. Transport of metal ions by 2 through a liquid membrane was also examined.
Preparative Derivatization of endo-Dicyclopentadiene via Metallation
Authors: Kumagai Takashi , Aga Michihiro , Okada Keiji , Oda Masaji
Published: July 2006

endo-Dicyclopentadiene has been selectively metallated with the base complex BuLi·t-BuOK in hexane at the olefinic positions in the norbornene moiety and a number of derivatives prepared by reaction of the metallated intermediate with electrophilic reagents. In particular, bromodicyclopentadiene thus obtained is a useful stock precursor for lithiodicyclopentadiene.
The Reaction between Hydrogen Spiro-Borates and Carbinol Form of Crystal Violet in Toluene with Applications to Reagent Selection in Extraction-Spectrophotometry of Boron
Authors: Sengupta Susanta K , Balasubramanian O
Published: July 2006

A study on equilibrium and kinetics of the reactions of boron complexes of a judiciously chosen series of hydroxy and dicarboxy acids (benzilic acid, mandelic acid, 3-chloro- and 4-hydroxy mandelic acid, salicylic acid, and phenylmalonic acid) as well as of the free acids with carbinol form of crystal violet in toluene demonstrated the distinct superiority of mandelic acid over the others, as a reagent for extraction-photometry of boron.
Synthesis of Tribromoacetic Anhydride and Its Reaction with Dimethyltin(IV) Oxide
Authors: Parkash Ram , Meena Meena , Singh Sukhjinder
Published: July 2006

The synthesis of previously unknown tribromoacetic anhydride and its reaction with dimethyltin(IV) oxide is reported. The compounds were characterized by analytical methods, IR, 1H, 13C, 119Sn NMR, and MS (EI) spectral studies.
Preferential Incorporation of a Cyclopropyl σ Bond Over an Ethylenic π Bond in the TCNE Cycloaddition of 1,2-Dicyclopropylethylene. Occurrence of the Type-II Reaction in Some Disubstituted Substrates
Authors: Nishida Shinya , Masui Masakazu , Murakami Masashi , Imai Toshiro , Tsuji Takashi
Published: July 2006

Among the two types of cycloadditions known to take place in the reactions of cyclopropyl-substituted ethylenes (1) with tetracyanoethylene (TCNE) (type-1 gives a cyclobutane derivative (2) and type-II yields a vinylcyclopentane derivative (3), the type-II reaction has been practically limited to occur in reactions of tetrasubstituted substrates. However, some disubstituted substrates, namely cis- and trans-1,2-dicyclopropylethylene (4 and 5), were found to produce a mixture of 2 (R1=R2 or R3=H, R2 or R3=cyclo-Pr) and 3 (R1=R2 or R3=H, R2 or R3=cyclo-Pr). In acetonitrile at 80°C, 2 predominated in the reactions of both 4 and 5, but 3 became the major adduct in 1,2-dichloroethane or benzene. The other 1,2-disubstituted ethylenes, such as 1-cyclopropylpropene, 1-cyclopropyl-3-methyl-1-butene and 1-cyclopropyl-3,3-dimethyl-1-butene, produced a small amount of 3 in solvents of low polarity; the type-II, however, has never become a major process. Parent vinylcyclopropane failed to give the type-II adduct in all of the solvents examined. Participation of the cyclopropyl σ bond in the reaction with TCNE is thus shown to have a scope wider than that presumed previously; hence, both the type-I and the type-II processes may be the two principal modes of the reaction of 1 with TCNE.
Stereochemical Control in Microbial Reduction. 18. Mechanism of Stereochemical Control in the Diastereoselective Reduction with Baker’s Yeast
Authors: Nakamura Kaoru , Kawai Yasushi , Miyai Takehiko , Honda Sohichi , Nakajima Nobuyoshi , Ohno Atsuyoshi
Published: July 2006

Reduction of a variety of 2-alkyl-3-oxobutanoates with bakers’ yeast yields the corresponding l-(3S)-hydroxy esters with exclusive enantioselectivity, while the diastereoselectivity, syn/anti ratio, varies depending on the structure of the alkoxyl moiety. In order to elucidate the mechanism for this stereochemical control, oxidoreductases that reduce 2-alkyl-3-oxobutanoate have been isolated from the cells of bakers’ yeast and purified. Two dominant competing 2-alkyl-3-hydroxybutanoate oxidoreductases have been obtained: one of them reduces 2-alkyl-3-oxobutanoates stereoselectively yielding the corresponding l-syn-hydroxy esters, whereas the other affords a mixture of l-syn- and l-anti-hydroxy esters. The experimental results on stereoselectivity have nicely been simulated using kinetic parameters elucidated.
Light-Induced Electron-Transfer Reaction into Rs. rubrum Chromatophores from a Pt Electrode
Authors: Erabi Tatsuo , Matsumoto Kiyoharu , Takahashi Noritaka , Hirata Kumiko , Wada Masanori
Published: July 2006

A platinum electrode immersed in a chromatophore suspension brought about, upon illumination, a cathodic photocurrent under potentiostatic conditions. The photocurrent action spectrum coincided fairly well with the absorption one of a chromatophore suspension, showing maxima at 600, 800, and 875 nm. The photocurrent increased with an increasing cathodic shift of the applied potential up to about −500 mV; two successive waves were observed on the photocurrent. The mechanism for the generation of the photocurrent is discussed.
Selective Potential Response of a Poly(N,N-dimethylaniline)/Poly(o-chloroaniline) Dual-Layer Coated Electrode to Dissolved Iodide Ions
Authors: Yano Jun
Published: July 2006

Poly(N,N-dimethylaniline) (PDA) was easily obtained by an anodic oxidation of N,N-dimethylaniline in acidic media. PDA is a semiconductor having positively charged sites as quaternary ammonium groups in its polymeric backbone. It was possible for a PDA-film coated electrode to incorporate I− electrostatically; I− in the film was then oxidized electrochemically. Further, the oxidized products of I− still remained in the film. Although the electrode responded to dissolved I− potentiometrically, the response was disturbed by the presence of other redox species. On the other hand, poly(o-chloroaniline) (PCA) was also easily prepared by the electro-oxidation of o-chloroaniline in acidic solutions. On a PCA-film coated electrode, only the redox wave of I2/I− was observed, though PCA, itself, was electroinactive. In other words, the PCA film responded to I− selectively. The dual-layer (a PDA film incorporated oxidized products of I− and PCA film) showed a selective Nernstian response to dissolved I−.
Biosynthesis of Mutant β-d-Galactosidases Containing Nonnatural Aromatic Amino Acids by Esherichia coli
Authors: Ueda Takehiko , Ueda Mitsuyoshi , Tanaka Atsuo , Sisido Masahiko , Imanishi Yukio
Published: July 2006

Mutant β-d-galactosidases containing nonnatural aromatic amino acids were produced by misincorporation during protein overproduction by Esherichia coli. The incorporation of 3-(1-pyrenyl)-l-alanine (pyrAla) was confirmed by fluorescence measurement of the produced enzyme, although the replacement frequency was low. Some of mutant enzymes showed improved thermostability.
Formation of Na0.9Mo6O17 in a Solid-Phase Process. Transformations of a Hydrated Sodium Molybdenum Bronze, Na0.23(H2O)0.78MoO3, with Heat Treatments in a Nitrogen Atmosphere
Authors: Eda Kazuo , Furusawa Kouichi , Hatayama Fumikazu , Takagi Sadao , Sotani Noriyuki
Published: July 2006

The transformations of hydrated sodium molybdenum bronze, Na0.23(H2O)0.78MoO3, with heat treatments in a nitrogen atmosphere are as follows: Na0.23(H2O)0.78MoO3 (AD) \xrightarrowat 330 K Na0.23(H2O)0.5MoO3 (VD) \xrightarrowat 457 K Na0.23MoO3 (with VD structure) \xrightarrowat 583 K Na0.9Mo6O17 + small amount of other materials \xrightarrowat 800 and 900 Kmeit. This indicates a new and variable formation process of alkali metal molybdenum bronzes. In this process, Na0.9Mo6O17 was formed in the solid phase without the formation of any intermediate products. Its formation temperature was about 600 K, which was less than those of the usual preparation methods by about 200 K.
NMR Studies on Reorientational Motion of Hydrated D2O Molecules of Halaide Ions (F−, Cl−, Br−, and I−) in Dilute Aqueous Solutions
Authors: Shimizu Akio , Taniguchi Yoshihiro
Published: July 2006

The spin–lattice relaxation rates of the D and 17O nuclei of D2O molecules have been measured for dilute aqueous solutions of potassium halides (KF, KBr, KCl, KI) in the concentration range below 1.0 mol kg−1 at 25°C. The agreement between the B\barx′ coefficients of the spin–lattice relaxation rate (reorientational motion) and the B− coefficients of the solution viscosity of the anions is somewhat better than that of the cations. The reorientational motion of hydration for D2O molecules of Cl−, Br−, and I− ions was anisotropic; this anisotropic motion is enhanced with increasing ion radius. On the other hand, the hydration D2O molecule of the F− ion was approximately isotropic.
Synthesis and Absorption Spectral Properties of New Merocyanine Dyes Derived from 1,1 Diaryl-2-propyn-1-ols
Authors: Nakatsuji Shin’ichi , Yahiro Tomio , Nakashima Kenichiro , Akiyama Shuzo , Nakazumi Hiroyuki
Published: July 2006

A series of push-pull butadiene dyes (new merocyanine dyes) containing 3,6-bis(dimethylamino)fluorenylidene, thioxanthenylidene, or 10-(9-xanthenylidene)-9(10H)-anthrylidene chromophore was easily synthesized from the corresponding 1,1-diaryl-2-propyn-1-ol systems. Their absorption spectral properties were examined and the relationship between their light absorption properties and chemical structures is discussed in comparison with the results from PPP-SCF-CI-MO calculations. The influence of the solvent polarity on the 1⁄λmax(=wave number)-values of the dyes was investigated, and the solvatochromic nature compared with the known solvent polarity parameters such as ET30, Z, χR, πazo* on 2-[2-[3,6-bis(dimethylamino)fluorenylidene]ethylidene]-1,3-indandione.
Syntheses of Titanium Butoxide Tris(polyfluoroalkanoate) and Surface Modification of Calcium Carbonate
Authors: Yoshino Norio , Shiraishi Yukihide , Hirai Hidefumi
Published: July 2006

Titanium butoxide tris(5H-octafluoropentanoate), Ti(OnC4H9)[OCO(CF2)4H]3, titanium butoxide tris(7H-undecafluoroheptanoate), Ti(OnC4H9)[OCO(CF2)6H]3, titanium butoxide tris(9H-hexadecafluorononanoate), Ti(OnC4H9)[OCO(CF2)8H]3, and titanium butoxide tris(perfluorooctanoate), Ti(OnC4H9)[OCO(CF2)6CF3]3, were prepared by the reaction of titanium butoxide trichloride with sodium fluoro-substituted acylates in 1,1,2-trichloro-1,2,2-trifluoroethane. These compounds were characterized on the basis of elemental analysis as well as their IR, 1H NMR, 13C NMR, and 19F NMR spectra. In the compounds produced, a Ti–OCO bond was stable in water, although a Ti–OR bond was only moderately stable in water. A surface modification against calcium carbonate was attempted by using these products. From measurements of the contact angles θ(°) of water and toluene against a modified calcium carbonate surface, titanium butoxide tris(perfluorooctanoate) was found to be an effective substance for a new-type coupling agent, which increases the affinity between organofluoro polymers and some inorganic substances.
Physical and Chemical Properties of Mononuclear Cobalt Dioxygen Complexes with Tetraimidazolyl-Substituted Pyridine Chelates
Authors: Tamagaki Seizo , Kanamaru Yutaka , Ueno Masanori , Tagaki Waichiro
Published: July 2006

A new calss of mononuclear superoxocobalt complexs containing four equal imidazolyl-donors and one pyridyl-donor per cobalt(II) ion was prepared and their chemical and physical properties were compared with those of cobalt(II) Schiff-base type dioxygen complexes.
A Method for Preparing New Elongated-Shaped Silica Sols
Authors: Yoshida Akitoshi , Watanabe Yoshitane , Andoo Mikio , Tanimoto Kenji
Published: July 2006

An active silicic acid sol was added to a mixture of a Ca(NO3)2 aqueous solution and a NaOH aqueous solution, then the mixture was heated for several hours under stirring at 100–150°C to obtain a silica sol. The silica sol consisted of elongated-shaped colloidal particles desirable for film formation.
XANES Spectra of Co(ala)3 and Co(acac)3 in Solid and Solution
Authors: Sano Mitsuru
Published: July 2006

XANES spectra of [Co(ala)3] and [Co(acac)3] have been measured in solid and solution. Comparisons of spectra of the species in solid and solution give a basis for the spectral change being attributable to intermolecular interactions.
Molybdenum Pentachloride-Induced Reaction of Cyclopropyl-Substituted Carbonyl Compounds
Authors: Hirao Toshikazu , Nagata Shinichiro , Yamaguchi Makoto , Ohshiro Yoshiki
Published: July 2006

Molybdenum pentachloride induced the ring-opening reactions of cyclopropyl phenyl ketone or propyl 2-(trimethylsilylmethyl)cyclopropanecarboxylate to give 1-phenyl-1,2,4-trichloro-1-butene or cis-2-chloro-4-pentanolide, respectively.
Mechanism of the Reaction of NH(1Δ) with NO in Argon Matrix
Authors: Yokoyama Keiichi , Kitaike Hiroshi , Fueno Takayuki
Published: July 2006

Matrix-isolated hydrazoic acid HN3 admixed with NO was photolyzed by a low-pressure mercury discharge lamp. Product analysis based on the FTIR spectroscopy has revealed the formations of NH, N2O, OH, HNO, and HONO as photoproducts. From the comparisons of the amount of HN3 consumed with that of N2O produced, we conclude that the reaction of NH(1Δ) with NO proceeds mainly through the process NH(1Δ)+NO→N2O+H. The quantum yield of N2O is found to be φ1=0.7±0.1. The conclusion is in line with our previous results of the gas phase experiments at room temperature.
Synthesis of a Chiral α-(Aminooxy)arylacetic Ester. II. A Route through a Chiral 2-Hydroxy-2-phenylacetic Acid Derivative
Authors: Iwagami Hisao , Yatagai Masanobu , Nakazawa Masakazu , Orita Haruo , Honda Yutaka , Ohnuki Takashi , Yukawa Toshihide
Published: July 2006

A simple and practical synthetic route has been developed for the synthesis of a chiral α-(aminooxy) ester (S)-16, which is a synthetic intermediate for a potent antipseudomonal cephalosporin antibiotic M-14659. In this synthetic route, the key intermediate is α-hydroxy acid (R)-7 (100%ee), which is prepared by an asymmetric reduction of α-keto ester with NaBH4-(R,R)-tartaric acid followed by a hydrolysis and an optical resolution using l-Leu–NHNH2. (S)-16 is obtained stereoselectively through 3 steps from (R)-7. HPLC analyses and NMR studies have proved that the (S)-16 thus prepared is completely optically pure.
Synthesis of [6-(1,4,7,10-Tetraaza-12-cyclotridecyl)-1,4,8,11-tetraazacyclotetradecane]dinickel(II) Perchlorate and Its Electrocatalytic Property for Water Reduction
Authors: Mochizuki Katsura , Gotoh Hajime , Suwabe Masaaki , Sakakibara Tohru
Published: July 2006

A new bimacrocyclic ligand, in which 13- and 14-membered rings are linked together by a C–C bond, 6-(1,4,7,10-tetraaza-12-cyclotridecyl)-1,4,8,11-tetraazacyclotetradecane (L13−14), and its dinickel(II) complex, [NiII2L13−14]4+, were synthesized. The absorption spectra and cyclic voltammograms of [NiII2L13−14]4+ showed that it has properties of both the 13- and 14-membered rings. Cyclic voltammetry and controlled-potential electrolysis showed that [NiII2L13−14]4+ can serve as an electrocatalyst for water reduction to produce H2. The electrocatalytic efficiency for H2 produclion at −1.5 V was found to be as follows: [NiII2L14−14]4+ (L14−14: 6,6′-bi(1,4,8,11-tetraazacyclotetradecane))>[NiII2L13−14]4+≈[NiIIL14]2+ (L14: 1,4,8,11 -tetraazacyclotetradecane)>>[NiII2L13−13]4+ (L13−13: 12,12′-bi(1,4,7,10-tetraazacyclotridecane)).
Amination of Carboxylic Acids by Reductive Fixation of Molecular Nitrogen by Glow Discharge Against Aqueous Solution
Authors: Harada Kaoru , Igari Shun-ichiro , Munegumi Toratane , Takasaki Michiaki , Shimoyama Akira
Published: July 2006

Amination of several carboxylic acids by reductive fixation of molecular nitrogen was achieved by glow discharge against aqueous solution of these carboxylic acids. The yield of the aminated product is the highest in the case of maleic acid among carboxylic acids used. The addition of hydrochloric acid to the reaction mixture enhances the yields of aminated products. This may be caused by the fact that chloride anion is oxidized by hydroxyl radicals to chlorate ion, and the fixation of molecular nitrogen proceeds under relatively reducing conditions.
Regiospecific Ring Opening of Epoxides with Cyanotrimethylsilane on Solid Bases: Reaction Features, and Role of Metal Cations of Solid Bases
Authors: Sugita Keisuke , Ohta Akihisa , Onaka Makoto , Izumi Yusuke
Published: July 2006

A new attempt of utilizing solid acids and bases for ring opening of epoxides with Me3SiCN was investigated. Solid strong bases such as calcium oxide and magnesium oxide catalyzed the regio- and chemoselective ring opening of epoxides with Me3SiCN much more effectively than homogeneous catalysts. On CaO and MgO, the reactions of unsymmetrical epoxides with Me3SiCN afforded 3-trimethylsiloxyalkanenitriles in high yields through regio- and stereoselective attack of cyanide ion on the less substituted epoxycarbon. Additionally, on CaO, 2,3-epoxy-1-alkanol derivatives were selectively converted to the corresponding C-3 opened products by the attack of cyanide ion. In these cases no isocyanides were formed. It was suggested that CaO acted as a bifunctional catalyst; the lattice oxide anions of CaO activated Me3SiCN, and simultaneously calcium ions promoted the ring opening of epoxyalkanol as Lewis acid sites.
Temperature Distribution in Tubular Solid Oxide Fuel Cell
Authors: Kanamura Kiyoshi , Yoshioka Shoji , Takehara Zen-ichiro
Published: July 2006

The temperature distribution in the tubular solid oxide fuel cell (SOFC) was calculated by using a finite element method. In this study, specially, the heat generation and consumption caused by the entropy changes at anode and cathode were taken into account for the calculation of temperature distribution in SOFC. In order to estimate the tendency of temperature distribution, the current distribution and the partial pressure distributions of hydrogen, steam, and oxygen were obtained from the calculation by using the simple mathematical model. From the temperature distribution in the tubular SOFC, it can be seen that the temperature difference is largest in the region of porous cathode material. This indicates that the heat generation from the entropy change of cathode reaction has the significant effect for the temperature distribution in tubular solid oxide fuel cell.
Kinetic Studies on the Quenching Reaction of the Photo-Excited [Ru(bpy)3]2+ with [Co(edta)]− in the Presence of EDTA, CDTA, and C2O42−
Authors: Yamazaki-Nishida Suzuko , Nagai Aiko , Mouri Noriko , Kawashima Satoko , Kimura Masaru
Published: July 2006

In the presence of a sacrificial donor (such as ethylenediaminetetraacetic acid, trans-1,2-cyclohexanediaminetetraacetic acid or oxalic acid in a deaerated aqueous solution) [Co(edta)]− is reduced to [Co(edta)]2− by quenching oxidatively the photo-excited [Ru(bpy)3]2+ ([Ru(bpy)3]2+*). The reduction rate for the [Co(edta)]− increases with an increase in the concentration of the sacrificial donor, and is kept constant at [EDTA] ≥ 0.03 mol dm−3, [CDTA] ≥ 0.01 mol dm−3, or [C2O42−] ≥ 0.07 mol dm−3 at pH 4.6. The ratio [[Co(edta)]−]reacted : [EDTA]reacted : [[Co(edta)]2−]formed=2 : 1 : 2 is obtained at pH 5.2. The reaction rates were examined as a function of the concentrations of [Co(edta)]− and [Ru(bpy)3]2+ as well as the pH, ionic strength, and temperature of the solution, and the intensity of the incident light. In the presence of oxygen, the decrease of [Co(edta)]− is greatly suppressed and the formation of the hydrogen peroxide is appreciable. The reaction mechanism is presented in order to account for the obtained results.
Disposition of Ferrocenes in β- or γ-Cyclodextrin Cavity and Consideration on the Absorption Bands of Ferrocene
Authors: Kobayashi Nagao , Osa Tetsuo
Published: July 2006

By comparing the induced circular dichroism (ICD) spectrum of 1,4,7,10,13-pentaoxa[13](1,1′)- ferrocenophane, I, in the presence of β-cyclodextrin (β-CDx) with that of ferrocenes (Fcs) in β-CDx or γ-CDx cavity, the disposition of Fcs in the CDxs is determined. Thus, the orientation of Fc in the Fc: β-CDx 1:1 complex and ferrocenecarboxylic acid (FcMA) in β-CDx at pH 2 is considered to be nearly parallel to the molecular axis of β-CDx, while that of Fc in the Fc: γ-CDx 1 : 1 complex, FcMA in β-CDx cavity at pH 9, and FcMA and ferrocenedicarboxylic acid (FcDA) in γ-CDx cavity appears to be close to normal to the molecular axis of the CDx. In addition, based on the ICD spectra, an intense band of Fcs at around 200 nm is assigned as a charge–transfer (CT) transition between the cyclopentadienyl (Cp) rings and iron(II). The advantage of using CDxs for the determination of the polarization direction of absorption bands of chromophore molecules is mentioned in comparison with previous methods.
Formation of Molecular Complexes with Calixarenes as Detected by Induced Circular Dichroism
Authors: Arimura Takashi , Shinkai Seiji
Published: July 2006

Calix[n]arenes (n=4 and 6) bearing (S)-5-oxo-2-pyrrolidinylcarbonyloxyl groups on the lower rim were synthesized. In chloroform, the hexamer bearing six (S)-5-oxo-2-pyrrolidinylcarbonyloxyl groups could “bind” ferrocenecarboxylic acid through hydrogen-bonding interactions, the complexation being conveniently detected by induced circular dichroism (ICD) spectroscopy (λmax 445 nm). On the basis of the examination of acyclic reference compounds, the appearance of the ICD band was explained as such that one pyrrolidone unit acts as a binding site and the chiral center in the neighboring pyrrolidone unit affects the transition moments in the ferrocene π-system. The association constant for the 1 : 1 complex was estimated to be 680 M−1. This is a new, convenient method for detecting the formation of molecular complexes with calixarenes in organic media.
Synthesis of 7-Substituted 6,7-Dihydro-5H-pyrrolo[3,4-b]pyridin-5-ones. Reaction of 7-Hydroxy Derivatives with Nucleophiles
Authors: Goto Takehiko , Utsunomiya Shin , Aiba Hiroshi , Hayasaka Hirotaka , Endo Mikihiro , Watanabe Reo , Ishizaki Takeshi , Sato Ryu , Saito Minoru
Published: July 2006

Various 7-substituted 6,7-dihydro-5H-pyrrolo[3,4-b]pyridin-5-ones are synthesized by the reaction of the corresponding 7-hydroxy derivatives with nucleophiles involving active methylene compounds, aromatics, alcohols, p-toluenethiol, benzenesulfinic acid, triethyl phosphite, ammonia, and amines under acidic or basic conditions. Some synthetic applications of the products obtained are demonstrated to give a 7-methylene derivative and fused tricyclic derivatives.
The Acidic Property and Catalytic Activity of MoO3–SiO2–Al2O3
Authors: Sabu Kuzhunellil Raghavan Pillai , Rao Kalur Vijayachandra C , Nair Chandrathil Govindan Ramachandran
Published: July 2006

The ternary oxide system MoO3–SiO2–Al2O3 was prepared by coprecipitation method. The pH of coprecipitation has been varied from pH=2 to pH=8 and its effect on the acidic properties of the ternary oxide acidic system was studied by butylamine titration. The MoO3–SiO2–Al2O3 prepared from highly acidic solution has low acid strength. The total acid amount of the ternary oxide decreased considerably at higher pH (>6) of coprecipitation. It was found that the total acid amount of MoO3–SiO2–Al2O3 containing 9.7% (by weight) of MoO3 and silica to alumina molar ratio 16.6 is very high compared with that of SiO2–Al2O3 of the same silica to alumina molar ratio. The acid strength of SiO2–Al2O3 is reduced by the incorporation of MoO3. Increase in calcination temperature increased the acid strength. The catalytic activity of MoO3–SiO2–Al2O3 was found to be very high for the alkylation of toluene with 2-propanol. The products are found to be o-cymene, p-cymene, and three isomers of diisopropyltoluenes. Reaction temperature >200°C, higher liquid hourly space velocity, and higher alcohol content in the feed decreased the total conversion of 2-propanol to isopropyltoluenes. The acidic property and catalytic activity of MoO3–SiO2–Al2O3 are not considerably reduced up to four successive regeneration cycles.
Photocatalytic Activities of Bi2O3, WO3, and Fe2O3: An Assessment through Decomposition of Peroxomonosulfate in Visible Radiation
Authors: Maruthamuthu Pichai , Gurunathan Karuppusamy , Subramanian Esaikkiappan , Ashokkumar Muthupandian
Published: July 2006

Bi2O3 semiconductor powder (Eg=2.8–2.9 eV) was chosen for the first time to effect photocatalysis and was found to decompose peroxomonosulfate (PMS) with visible light of λ>400 nm. Doping of Bi2O3 with Cu(II)-ion considerably enhanced the photocatalytic efficiency. The effects of variation of (i) the [dopant] in Cu(II)/Bi2O3, (ii) the catalyst amount, and (iii) the initial [PMS] on the rate of decomposition of PMS were investigated. It was observed that (a) 4 atomic % was the optimum [dopant] for Cu(II)/Bi2C3, (b) the rate increased linearly with increase in catalyst amount, and (c) the decomposition of PMS followed a Langmuir kinetics in the concentration range, [PMS]0=0.5–3.0×10−3 mol dm−3. A suitable reaction mechanism is proposed for the decomposition of PMS involving all the possible reactions. A comparative analysis of the photocatalytic activities of undoped and Cu(II)-doped Bi2O3, WO3, and Fe2O3 indicated that Cu(II)-doping enhances the activity of Bi2O3 to a greater extent than those observed with the other two semiconductors. This photocatalytic decomposition of PMS is one of the examples of visible light assisted reaction which otherwise takes place under UV radiation (λ≤280 nm) only.
Some Physico-Chemical Studies on Molecular Semiconductors Based on Charge Transfer Complexes of Substituted Phenothiazines with Iodine
Authors: Singh Ram Adhar , Singh Ranjana , Verma Shiva Mohan
Published: July 2006

The synthesis, chemical and structural characterizations, and thermal, spectral, electrical, and magnetic properties of six molecular semiconductors based on the charge transfer complexes of substituted phenothiazines namely; phenothiazine, 2-chlorophenothiazine, 2-(trifluoromethyl)phenothiazine, 2-acetylphenothiazine, N-acetylphenothiazine, and N-benzoylphenothiazine with molecular iodine have been reported in this paper. These complexes have been found to have 2 : 3 stoichiometries. X-Ray diffraction data show that first three complexes have orthorhombic structure whereas the other three are amorphous. Thermal analysis shows that the complexes are thermally stable upto 120 °C. The existence of monomeric and dimeric cationic species of phenothiazines has been proposed on the basis of spectral data. These complexes have been found to be molecular semiconductors having moderately high electrical conductivities and activation energies. The segregated stacking of phenothiazine and iodine moieties has been proposed to be responsible for high conductivity values and a mixed conductivity mechanism accounts for temperature dependence of electrical conductivities of these complexes.
Study of the Vibrational Spectra and Determination of Thermodynamic Functions of 2-Pyridone and 2-Pyridone-N-d
Authors: Medhi Kanak Chandra
Published: July 2006

The infrared spectra in the polycrystalline state (4000–50 cm−1), in melt and in solution and the Raman spectra in the solid state and in melt of the substances have been studied for 2-pyridone and 2-pyridone-N-d. A vibrational assignment of the observed frequencies is given. Ideal gas state thermodynamic functions of the two isotopic molecules based on the observed fundamental frequencies have been determined in the temperature range 200–1500 K.
Reaction of Amidine Phenylogous with p-Benzoquinones
Authors: El-Din Ahmed M Nour , Mourad Aboul-Fetouh E , Hassan Alaa A , Gomaa Mohsen A
Published: July 2006

N-(4-Dimethylaminobenzylidene)anilines and N1-(4-dimethylaminophenyl)-N1,N2-diphenylformamidine reacted with tetrachloro-, tetrabromo,- and tetrafluoro-p-benzoquinones via charge-transfer complexes formation giving 2-monoarylamino-3,5,6-trihalo-p-benzoquinones and 2,5-bis(arylamino)-3,6-dihalo-p-benzoquinones. The course of the reaction leading to the formation of the products has been interpreted.
Effects of Six-Membered Chelate Rings in the Oxidant Cobalt(III) Complexes on the Stereoselective Oxidation of [Co(en)3]2+
Authors: Tatehata Akira , Akita Hiromi
Published: July 2006

The stereoselectivities in the oxidation of [Co(en)3]2+ by chiral cobalt(III) complexes containing six-membered chelate ligands, such as malonate, β-alaninate, and acetylacetonate ions, were examined. All of the oxidant complexes with the Δ-configuration studied here, like the corresponding oxalato and glycinato complexes containing five-membered chelate rings, led to an excess of Λ-[Co(en)3]3+, with the exception of Δ-[Co(ox)(acac)2]−.
Solvent Bulkiness Effect on N,N-Dimethylformamide Exchange of the o-Phenylenediamine-N,N,N′,N′-tetraacetatoferrate(III) Complex as Studied by a High-Pressure NMR Method
Authors: Mizuno Masafumi , Funahashi Shigenobu , Nakasuka Noriyuki , Tanaka Motoharu
Published: July 2006

Activation parameters for solvent exchange of the title complex in N,N-dimethylformamide (DMF) have been determined as follows: k(25°C)=(3.4±0.2)×107 s−1, ΔH\eweq=18±3 kJ−1 mol−1, ΔS\eweq=−40±10 J K−1 mol−1, and ΔV\eweq=10±2 cm3 mol−1. The positive value of ΔV\eweq indicates that the DMF exchange proceeds via a dissociative interchange mechanism.
Epoxidation of 2-Butene-1,4-diones with Hydrogen Peroxide in the Presence of a Catalytic Amount of Quaternary Ammonium Iodide
Authors: Sayama Shinsei , Inamura Yutaka
Published: July 2006

The epoxidation of 1,4-disubstituted 2-butene-1,4-diones with 30% aq H2O2 in the presence of a catalytic amount of quaternary ammonium iodide afforded 2,3-epoxy-1,4-butanediones in high yield.
Formation of Acyclic cis-Azobenzene without Light
Authors: Tamaoki Nobuyuki , Yoshimura Sawako , Yamaoka Tsuguo
Published: July 2006

Reduction mixture of bis(4-nitrobenzyl) ether contained a considerable amount of cis-4,4′-dimethylazobenzene.
Reduction of Carbon Dioxide to Give Unstable Carbon Oxides. An Attempt of Capture of Unstable Carbon Oxides Formed by the Reduction of Carbon Dioxide with Benzoin Carbanion Using Phenyliodonium Bis(phenylsulfonyl)methylide
Authors: Akiyama Fuminori
Published: July 2006

Capture of unstable carbon oxides formed by the reduction of carbon dioxide (CO2) with benzoin carbanion using phenyliodonium bis(phenylsulfonyl)methylide (1) was tried. In this reaction decomposition of the ylide 1 by the unstable carbon oxides was observed to give phenylsulfonylcarbene : CH(SO2Ph).
Synthesis of Phosphorus-Containing Polymers with Aziridine Ring
Authors: Trendafilova-Gercheva Dimitrina , Troev Koljo , Georgieva Milka
Published: July 2006

It has been established that phosphorus containing alkylammonium salts obtained by alkylation of primary amines with bis(2-chloroethyl) phosphonate or alkyl 2-chloroethyl phosphonate can be transformed into corresponding compounds with aziridine ring.
Elucidation of Solvatochromism for the Ligand Field Absorption Bands of Polyamine-N-polycarboxylato Cobaltate(III) and Chromate(III) Complexes of [M(N)2(O)4] Type
Authors: Kaizaki Sumio , Koine Norio , Sakagami Narumi
Published: July 2006

The solvatochromism of the first ligand field absorption bands and/or the solvent dependence of 13C and 59Co NMR shifts for trans- and cis-[M(N)2(O)4] type complexes of cobalt(III) or chromium(III) with various kinds of polyamine-N-polycarboxylato ligands was elucidated in terms of the angular overlap model (AOM) parametrization. On the basis of the difference in the solvent-dependence of spectroscopic data of the complexes studied in various solvents, it was found that the solvatochromism could result from variations of the metal-ligand σ and/or π bond interactions (expressed by the eσ(O), eσ(N), and anisotropic eπ(O) AOM parameter values) due to the preferential solvation toward the oxygen Pπ orbitals coplanar with the M(O)2 coordinate planes.