bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electrochemical Studies of Poly(mercaptohydroquinone) and Poly(mercapto-p-benzoquinone) Film Prepared by Electrochemica Polymerization. IV. Preparation of Palladium Microparticles on the Polymer Film
Authors: Arai Gorou , Matsumoto Kiyofumi , Murofushi Toshiyuki , Yasumori Iwao 
Published: July 2006

Abstract
The electrodeposition of Pd at microgram levels onto an electroconductive poly(hydroquinone/p-benzoquinone) film-coated glassy carbon electrodes is described. The polymer films were chemically modified with Pd pyridine complex and/or with Pd thiolate prior to the Pd electrodeposition. Controlled-potential electrolysis was applied to form Pd microparticles on the polymer film from an acid PdCl2 solution. The nucleation/growth of Pd microparticles was largely promoted by these chemical modifications. The Pd particles on the pyridine complex-modified electrode were closely dispersed and were spherically shaped, while on the thiolate-modified electrode the Pd deposits were irregular in shape. Both the electrodes thus prepared exhibited high activity toward the generation of hydrogen and had good stability in acidic solution.
Characterization of Metal Chelation with a Mutagenic Agent, 5-Bromouracil
Authors: Singh Udai P , Ghose Ranjana , Ghose Animesh K 
Published: July 2006

Abstract
The interaction of some trace metal ions with a chemical mutagen 5-bromouracil (5-BrU) has been studied spectroscopically and by magnetic measurements. 5-BrU is coordinated to the Mn(II), Ni(II), and Cu(II) ions through the N atom of N(1)H group and the O atom of C(4)=O group whereas to the Co(II), Zn(II), and Cd(II) ions through O atom of C(4)=O group only. The new complexes except Co(II) complex which are insoluble in water and other common organic solvents involve polymeric structures. The tentative νM–O and νM–N band assignments in the lower region favor coordination number six for all complexes.
Observation on the Fragmentation of Some Tosylhydrazones Using Electrochemically Generated Superoxide Ion
Authors: Singh Manorama , Mishra S C , Misra Ram A 
Published: July 2006

Abstract
Superoxide ion (O2\ewdot) generated in situ by electrochemical reduction of molecular oxygen in dimethylformamide (DMF) at mercury cathode, behaves as a mild effective base to deprotonate the acidic hydrogen from tosylhydrazones of benzophenone (1), benzaldehyde (2), cyclohexanone (3), benzoin (4), acetophenone (5), and benzil (6) finally affording tetraphenylethene (1a), trans-stilbene (2a), cyclohexene (3a), deoxybenzoin (4a), acetophenone azine (5a), and 4,5-diphenyl-1-tosylamino-1,2,3-triazole (6a) respectively in good to excellent yield.
A 13C NMR Study of Octyltrimethylammonium Bromide Solutions with and without Urea
Authors: Uzu Yuhei , Saito Yasushi , Terao Hideyasu , Yokoi Masatoki 
Published: July 2006

Abstract
The effect of urea on the micelle formation of octyltrimethylammonium bromide (C8TAB) solution in D2O was studied by 13C NMR chemical shift and 13C spin-lattice relaxation time. The presence of urea increases the critical micelle concentration (cmc) of C8TAB solution. In the micellar state, the segmental motions of methylene chain adjacent to the polar head group are strongly affected by urea.
Convenient Preparation of Acetals over Hydrous Zirconium Oxide
Authors: Shibagaki Makoto , Takahashi Kyoko , Kuno Hideyuki , Matsushita Hajime 
Published: July 2006

Abstract
Aldehydes and ketones were efficiently converted to the corresponding acetals by the reaction with ethylene glycol over hydrous zirconium oxide. The reaction could proceed under reflux condition or at room temperature. The compound, which was unstable in acid, was also acetalized by this catalyst.
Synthesis of (5Z,13S)-5-Tetradecen-13-olide, Aggregation Pheromone of the Cryptolestes Grain Beetle, Employing Asymmetric Bioreduction with Immobilized Bakers’ Yeast Entrapped in Calcium Alginate Beads
Authors: Naoshima Yoshinobu , Nakamura Akihiro , Munakata Yoshihito , Kamezawa Makoto , Tachibana Hojun 
Published: July 2006

Abstract
(5Z,13S)-5-Tetradecen-13-olide, a synergist of the aggregation pheromone of the flat grain beetle, was synthesized in an optically pure form by means of an asymmetric bioreduction of the intermediate acetylenic keto acid with immobilized bakers’ yeast entrapped in gels of calcium alginate.
Photolysis of Diary Triphenylmethylphosphonates
Authors: Shi Min , Okamoto Yoshiki , Takamuku Setsuo 
Published: July 2006

Abstract
Synopsis. Upon UV irradiation in methanol,diaryl triphenylmethylphosponate underwent three types of elimination of two aryl groups to give biaryls: the first is an α,α-elimination of two phenyl groups from a triphenylmethyl group which leads to formation of the corresponding carbene intermidiate; the second is an elimination of two aryl groups from a diaryl ester group to afford biaryl; the third is an elimination of phenyl and aryl groups from both moieties to give arylbenzene.
Hydrogenation of Monoalkylbenzenes over Supported Pt Catalysts. Influence of Different Variables on the Catalytic Activity
Authors: Aramendía M Angeles , Borau Victoriano , Jiménez César , Marinas J María , Rodero Francisco , Sempere M Eugenia 
Published: July 2006

Abstract
The catalytic activity of various supported Pt systems used in the hydrogenation of monoalkylaromatic hydrocarbons is markedly influenced by different variables involved in the catalyst synthesis (support, solvent, metal salt, and reduction temperature of the precursor). By analyzing the influence of the substrate structure, we found the following reactivity order: t-butylbenzene&gt;isopropylbenzene&gt;ethylbenzene&gt;toluene&gt;benzene. The results obtained conform to the Hammet equation.
A Study of the Atherton–Todd Reaction Mechanism
Authors: Troev K , Kirilov E M G , Roundhill D M 
Published: July 2006

Abstract
It has been shown that alkylammonium methyl phosphonates [CH3OP(O)HO]− [NCH3R3]+ and sodium ethyl phosphonate [CH3CH2OP(O)HO]− Na+ catalyse the Atherton–Todd reaction. It has been established that the alkylammonium salts themself react with carbon tetrachloride to give chloroform, resulting in the postulate that base activation leads to the monoalkyl phosphonate anion.
Electrochemical Behavior of High Transition Temperature Superconducting Oxides
Authors: Ohkawa Kiyomi , Itoh Kiminori , Fujishima Akira 
Published: July 2006

Abstract
Typical high transition temperature (high-Tc) superconducting oxides were used as electrodes in order to investigate their electrochemical behavior at room temperature. Chemical stability of these materials in various solutions was also tested. These superconducting oxides were stable in nonaqueous solutions, but is was very difficult to protect electrical contacts from the solvents because of porous structures of these oxides. These materials were rather stable in highly concentrated alkaline solutions while unstable in neutral and acid solutions. Electrochemical experiments were carried out in alkaline solutions, and the following results were obtained: (1) All of the high-Tc superconducting oxides were unstable at cathodic polarization. (2) Oxygen evolution was observed under anodic polarization. (3) These oxides behaved like p-type semiconductros though no photocurrents were detected. (4) [Fe(CN)6]3−⁄4− served as a redox couple for all of these high-Tc oxides.
Picosecond Laser Photolysis Studies on the Photoreduction of Excited Benzophenone by Diphenylamine in Solutions
Authors: Miyasaka Hiroshi , Mataga Noboru 
Published: July 2006

Abstract
The mechanism of photoreduction of benzophenone (BP) by diphenylamine (DPA) in isooctane as well as acetonitrile and other polar solvents has been investigated by means of picosecond laser photolysis and time-resolved transient absorption spectral measurements. The results of measurements have demonstrated clearly that the hydrogen abstraction and charge transfer (CT) or ion pair (IP) state formation by electron transfer are competing at encounter between triplet benzophenone (3BP*) and DPA both in nonpolar and polar solvent, and the CT or IP state relaxed with respect to the donor acceptor configurations and solvation does not contribute to the ketyl radical formation. It has been concluded that the very short-lived CT state at encounter between 3BP* and DPA plays a crucial role in the hydrogen abstraction reaction, i.e. the mutual orientation of 3BP* and DPA in this very short-lived CT state at encounter will determine the successive process, the formation of the ketyl radical or relaxed CT or IP state.
Synthesis of Optically Active Hexahydrofuro[2,3-b]furan, A Nonchromophore Moiety of Asteltoxin
Authors: Nishiyama Shigeru , Kanai Hiroki , Yamamura Shosuke 
Published: July 2006

Abstract
An optically active nonchromophore moiety of asteltoxin carrying a hexahydrofuro[2,3-b]furan structure has been successfully synthesized from a branched-chain d-xylohexofuranose derivative.
Highly Stereoselective Synthesis of Two Natural Olefinic Diols via N-Oxide [2,3]Sigmatropic Rearrangement
Authors: Sato Kikumasa , Inoue Seiichi , Iwase, Norimichi , Honda Kiyoshi 
Published: July 2006

Abstract
The [2,3]sigmatropic rearrangement of α-substituted N,N-dimethylmethallylamine N-oxides results in a highly stereoselective formation of trans olefins oxygenating at the allylic position, and providing a quite efficient synthesis of cuspidiol and plaunotol.
Medium Effects on the Molecular Electronic Structure. III. Quantum-Chemical Analysis of Solvent-Induced 13C NMR Chemical Shift Changes of Some Polyene Compounds
Authors: Sakurai Minoru , Hoshi Hajime , Inoue Yoshio , Chûjô Riichirô 
Published: July 2006

Abstract
A reaction-field theory (Hoshi et al., J. Chem. Phys., 87, 1107 (1987)) is applied to the analysis of solvent-induced 13C chemical shift changes of some polyene compounds. The solvent dependence of the 13C chemical shifts is calculated by means of the INDO-finite perturbation method combined with this theory. It is shown that the calculations well reproduce characteristic 13C shift changes observed in aprotic solvents. This indicates the validity of the theory. In addition, the origin of the solvent-induced 13C shifts is discussed on the basis of the electronic distribution obtained.
Magnetic Field Effects on the Dynamics of Biradicals Generated from Benzophenone and Diphenylamine Bifunctional Chain Molecules
Authors: Tanimoto Yoshifumi , Okada Natsuo , Takamatsu Shinji , Itoh Michiya 
Published: July 2006

Abstract
The magnetic field effects (MFE) on the lifetimes of triplet biradicals generated from the intramolecular photoreaction of bifunctional chain molecules, α-(4-benzoylphenoxy)-ω-[4-(phenylamino)phenoxy]alkanes (BP–O–n–O–DPA, n=2–16) were studied by laser flash photolysis. MFE on the biradical lifetimes are strongly affected by magnetic field, chain length, and solvent. The effects are interpreted in terms of the hf-relaxation mechanism. Lifetime change due to T−–S level crossing was observed in the biradicals with n=2 and 4. The singlet and triplet degeneracy of biradicals occurs when n≥6.
Fluorescence Behaviors of 3,3-Bis(8-quinolyloxymethyl)oxetane: Effects of Solvents, Carrier-Concentration, and Metal Ions on the Fluorescence Intensity
Authors: Hiratani Kazuhisa , Nomoto Masayo , Ohuchi Shoukichi , Taguchi Kazuhiro 
Published: July 2006

Abstract
The effects of solvents, the concentration of 3,3-bis(8-quinolyloxymethyl)oxetane (1), and the presence of metal ions on the fluorescence intensity of 1 have been investigated. The fluorescence intensity of 1 considerably increased when measured in chloroform, acetonitrile, or dioxane, though resulting in a comparably small increase when measured in ethyl acetate, toluene, or ethylene glycol. When acetone was used as the solvent, the fluorescence spectrum was hardly observed. When the concentration of 1 was adjusted to near 0.1 mmol dm−3, the intensity became maximum in each solvent used, except for acetone. It was observed that the fluorescence intensity of 1 rapidly decreased in a concentration range over 0.1 mmol dm−3. Furthermore, when metal ions were added into an organic solution such as acetonitrile, dioxane, or chloroform containing 1, the maximum increase in the fluorescence intensity was observed in the presence of lithium salt, whereas the intensity hardly changed in the presence of both potassium and sodium ions, compared with that of 1 in the absence of any metal ion. The presence of magnesium and barium ions also hardly brought about an increase of the intensity. On the other hand, heavy metal ions, such as silver(I) and copper(II), were observed to results in a slight decrease.
The Anisotropy of the Crystal Growth of Fe3O4 in an Aqueous Solution
Authors: Tamaura Yutaka , Itoh Tomoyuki , Matsuda Tsutomu , Abe Masanori 
Published: July 2006

Abstract
The anisotropy of the crystal growth of the spinel-type ferrites in an aqueous solution was studied using ferrite films piled up on the glass substrate by means of the thin liquid-film method (TLF method). From the difference between the values of the Oind (the parameter for the degree of the oxidation state), it was found that the Fe3O4 crystal grows in the (111) direction in the “oxidation state” (Oind=1.4×10−2 dm3 min−1), but in the (100) direction in the “Fe2+-rich state” (Oind=3.38×10−4 dm3 min−1). Although the reaction conditions for the formation of the Co(II)– and Zn(II)–ferrites were the same (both used in the “oxidation-state”; Oind=5.5–5.8×10−2 dm3 min−1), the anisotropy of the crystal growth was different between Co2+ [the (111) direction] and Zn2+ [the (100) direction]. These results were explained in terms of difference in the degree of the oxidation state (Oind). For the inverse spinel, the slower rate of the formation of the sublattice of the B site in the “oxidation-state” seems to cause the preferential formation of the A site, since the Fe3+ ions are preferentially incorporated into the A site. This results in the anisotropy in the (111) direction of Fe3O4 and Co(II)–ferrite (inverse spinel). On the contrary, in the “Fe2+-rich state”, the preferential formation of one of the two B sites (the Fe2+ occupies one of the two B sites in the inverse spinel) results in the anisotropy in the (100) direction of Fe3O4. For the normal spinel, the acceleration of the incorporation of the Fe3+ ions into the B site in the “oxidation-state” will result in the anisotropy in the (100) direction. This is the case for the anisotropy in the (100) direction of the Zn(II)–ferrite.
Hydroxide Ion-Selective Polymeric Membrane-Coated Wire Electrode Based on Oxomolybdenum(V) Tetraphenylporphyrin Complex
Authors: Abe Hideo , Kokufuta Etsuo 
Published: July 2006

Abstract
A coated wire electrode (CWE) was prepared by use of a poly(vinyl chloride)-supported liquid membrane containing oxoethoxo(5,10,15,20-tetraphenylporphyrinato)molybdenum(V) as a carrier. CWE based on such a metallo-porphyrin complex exhibits near-Nernstian responses to varying concentrations of NaOH, NaF, and C2H5OH, especially to NaOH over a wide concentration range. The pOH response curve was influenced by certain anions other than OH− ion, but not by cations such as Li+, Na+, K+, and Cs+. The mixed solution method gave a selectivity sequence OH−&gt;&gt;ClO4−&gt;NO2−&gt;F−∼SCN−&gt;I−&gt;NO3−&gt;SO3−&gt;Br−&gt;SO42−, with a preference for OH− over ClO4− by 104.6 and over F− (or SCN−) by 106.2. In addition, Cl− ion was found to have little interfering effect under conditions used in the measurements of selectivity coefficients. Both response-time profile and pOH-response curve scarcely varied even when CWE was stored in distilled water for 167 days.
The Specific Interaction of Mg and Alkaline Earth Metal Ions with Well-Defined Surfaces of α-HCrO2 and Cr2O3
Authors: Kittaka Shigeharu , Yamanaka Shigeru , Yanagawa Naoto , Okabe Takahiro 
Published: July 2006

Abstract
The selectivity sequences of Mg and alkaline earth ions to the surface of α-HCrO2 and Cr2O3 were investigated by measuring the electrophoretic mobility and the surface charge density. The latter was determined by means of potentiometric titration. The selectivity sequence of Mg and alkaline earth ions to the α-HCrO2 surface was determined as Mg&gt;Ca&gt;Sr∼Ba. This sequence was explained by the close configurational fitting of adsorbed metal ions to the solid surface. The reason is that the O–O distance on the (001) plane of Mg(OH)2 and Ca(OH)2 is similar to that of the α-HCrO2. On the amorphous Cr2O3 and crystalline Cr2O3, exposing mainly the (001) plane, the affinity of varying ions was comparable. The isoelectric points (IEP) of the chromium(III) hydroxide oxides and oxides were discussed in connection with their surface crystallinity as determined by electron microscopy. A lower crystallinity gives a slightly higher IEP.
Pillared Tetrasilicic Mica Catalysts Modified by Fixed Interlayer Cations. Classification of Fixation Mode by Cations
Authors: Sakurai Hiroaki , Urabe Kazuo , Izumi Yusuke 
Published: July 2006

Abstract
Fluor-tetrasilicic mica (TSM) exchanged with various types of cations was calcined at 300 °C for 3 h, and a part of the cations were fixed, followed by Al-pillaring. Thus, acidic pillared clay catalysts were prepared with a modification of the silicate layer by cations. Active catalysts for cumene cracking were obtained when modified by Sr2+, Ca2+, La3+, and Li+. The structural changes in the catalysts affecting the reaction activity was examined through X-ray diffraction, surface area, and 29Si-MASNMR measurements. The mode of cation fixation could be classified into five types, depending on the valence and size of the cations to be fixed. A group-2 cation (Na+) gave no modification effect compared with conventional nonmodified PTSM and managed only meager catalytic activity. The catalyst modified by group-5 by (Sr2+, Ca2+, La3+ etc.) cations or a group-1 (Li+) cation had a distinct pillared structure, characterized by an 18 Å basal spacing. These cations could be fixed either onto the basal oxygen surface for group-5 cations or into the octahedral vacancy for a group-1 cation. Though group-4 (Al3+, Mg2+) and group-3 (Cs+, K+) cations should also be fixed into the vacant sites and onto the surface, respectively, both types of modified catalysts formed unstable pillared structures, giving low catalytic activities.
Dynamic Process of Delayed Geminate Ion Pairs in X-Irradiated Squalane Solution of p-Terphenyl: An ODESR Study
Authors: Okazaki Masaharu , Nunome Keichi , Matsuura Kaoru , Toriyama Kazumi 
Published: July 2006

Abstract
The fluorescence detected ESR (ODESR) spectrum of a squalane solution of p-terphenyl was observed at various temperatures, concentrations, and microwave powers. Analysis of the ODESR amplitude, the line shape, and the area under the spectrum which is normalized by the fluorescence intensity led us to conclude that two geminate pairs (one with a terphenyl anion and a hole of the solvent squalane and the other with a terphenyl anion and its cation) contribute to the ODESR spectrum. It was also concluded that the former pair has a much shorter recombination time than that of the latter. It is suggested that though the hole center hops among the solvent squalanes, the rate is much less than that for the hole in aromatic solvents.
The Raman Spectral Study on the Solution Structure of Iron(III)-edta Complexes
Authors: Kanamori Kan , Dohniwa Hidekazu , Ukita Naoya , Kanesaka Isao , Kawai Kiyoyasu 
Published: July 2006

Abstract
The Raman spectra of iron(III) complexes with ethylenediaminetetraacetate were observed for the purpose of elucidating the structure of the complexes in solution. In a Raman spectral study on the solid complexes, the spectra in the 300–600 cm−1 region were found to be diagnostic to coordination geometry. Namely, the coordination number can be determined on the basis of the wavenumber difference of the two major bands observed in the 450–600 cm−1 region; the wavenumber differences observed for heptacoordinate complexes lie between 32 and 42 cm−1, while that for the hexacoordinate complex is 62 cm−1. Complexes containing a sexidentate edta exhibit a single intense band around 470 cm−1 in the 450–500 cm−1 region, while complexes containing a quinquedentate edta exhibit two intense bands in this region. These Raman spectral criteria were then applied for the determination of the solution structure. The Raman spectral features observed for solutions of Fe(III)-edta complexes indicate that the any alkali metal salts and acid salts of FeIII(edta)− give sexidentate heptacoordinate complex ions in water. The dimeric complex which is formed in an alkaline solution was characterized as being a dinuclear complex consisting of two quinquedentate hexacoordinate iron(III) moieties with a Fe–O–Fe bridging unit.
13C-CP-MAS NMR Spectroscopic Study of the Reaction Products of Osmocene with Lewis Acids
Authors: Watanabe Masanobu , Sano Hirotoshi 
Published: July 2006

Abstract
The adducts of osmocene derivatives with Lewis acids were studied by means of 13C-CP-NMR spectroscopy and other physicochemical techniques. The large low-field shifts found through 13C-CP-MAS NMR and 1H NMR spectroscopy and the organotin(IV) species found in the 119Sn-Mössbauer spectroscopic data suggest the presence of direct chemical bonds between the osmium atoms and the Lewis acids in the adducts.
ESR Studies on Salicylaldehyde Schiff Base Complexes of Copper(II). III. Dimer Formation on Bis(N-alkylsalicylideneaminato) copper(II) Complexes and Their Derivatives in Toluene
Authors: Yokoi Hiroshi , Takeuchi Akira , Yamada Shoichiro 
Published: July 2006

Abstract
Twenty one of the title complexes (abbreviated as Cu(X–sal–R)2; X=H, 5-Cl, or 5-Br and R=N-alkyl) in toluene have been extensively studied by the ESR method in order to obtain fundamental information on dimer formability and the dimeric structures of these complexes. The equilibrium constant (K) for 2 monomer \ightleftharpoons dimer has been determined by analyzing the concentration dependence of the intensity ratios of the dimer to the monomer ESR signals for frozen toluene solutions. The K values of the Cu(H–sal–R)2 complexes are remarkably R-dependent as follows: methyl (233)&gt;&gt;ethyl (10)∼isobutyl (9)&gt;other normal alkyl groups (∼4) for a series of the R groups with primary α-carbons, and cyclohexyl (75)&gt;&gt;isopropyl (7)&gt;s-butyl (&lt;&lt;1)&gt;cycloheptyl (∼0)&gt;t-butyl (0) for a series of the R groups with secondary and tertiary α-carbons, where the complex is denoted by R, followed by K (M−1) in parentheses. The complexes with R=nonyl or higher homologues form some polymeric species besides dimers and monomers. The K values remarkably increase by the introduction of X=5-Cl or 5-Br. The observed dimer ESR spectra have been analyzed by computer simulation in order to estimate the structural parameters (r and ξ) of parallel-planar dimers, where r is the Cu–Cu distance and ξ is the angle between the Cu–Cu direction and the normal to the molecular plane. These results indicate that most complexes form two types of dimers with different structures: type a, r=3.75 Å and ξ=37°; type b, r=4.10 Å and ξ=23°. The Cu(X–sal–methyl)2 complexes form only a-type dimers, while the others simultaneously form both types of dimers, except the complexes of R=isopropyl and cyclohexyl which form another type of parallel-planar dimers having a slightly tetrahedrally-distorted coordination geometry around each copper atom.