bluuebunny/crossref_metadata_2025_split huggingface dataset:
Restricted Rotation Involving the Tetrahedral Carbon. XXXVIII. Barriers to Rotation and Population Distributions of 9-(8-Methyl-1-naphthyl)fluorene and Its 1-Methyl Derivative
Authors: Mori Teruo , Oki Michinori 
Published: July 2006

Abstract
The title compounds were prepared to see the effect of an 8-methyl group on the populations and the barriers to rotation of rotamers. As expected, the substituent destablized the syn conformation to a considerable extent, although the extent appeared to be a little less than that of a 2-t-butylphenyl group. Atropisomers of 1-methyl-9-(8-methyl-1-naphthyl)fluorene were isolated. The barriers to rotation were discussed with reference to related compounds.
The Crystal Structure of Di-μ-Bromo-tris(triphenylphosphine)dicopper(II)
Authors: Negita Hisao , Hiura Morio , Kushi Yoshihiko , Kuramoto Masahiro , Okuda Tsutomu 
Published: July 2006

Abstract
The crystal structure of the Cu2Br2(PPh3)3·1.5C6H6 complex has been determined by three dimensional X-ray analysis. The crystals are monoclinic, and the space group is P21/c, with unit-cell parameters of a=14.122 (3), b=19.573 (4), c=25.985 (7) Å, β=128.99 (1)°, and Z=4. In the Cu2Br2(PPh3)3 molecule, one copper atom is three-coordinate, and the other, four-coordinate.
The Correlation between the Relative Retention Behavior and the Number of Chlorine Substituents in the Phenol Ring
Authors: Onodera Sukeo 
Published: July 2006

Abstract
The gas-chromatographic behavior of chlorinated phenols, m-cresols, and 3,5-xylenols on polar and nonpolar columns connected to either FID or ECD has been studied. The relative retention times (tR) for individual homologous series were determined as a function of the number of chlorine substituents in the molecule. It was found, for the homologous series of these chlorinated compounds, that a relationship between logtR and the number of chlorine substituents is of only limited use in the identification of individual chlorinated phenols.
The Molecular Structure of Δ-cis-α-[(S)-N,N′-Bis(2-pyridylmethyl)propylenediamine]dichlorochromium(III) Chloride
Authors: Hata Yasuo , Yamamoto Yukihiro , Shimura Yoichi 
Published: July 2006

Abstract
The molecular structure of Δ-cis-α-[CrCl2(S-picpn)]+ (S-picpn=(S)-N,N′-bis(2-pyridylmethyl) propylenediamine) was determined by X-ray analysis, the absolute configuration being confirmed to coincide with that assigned from the circular dichroism spectrum.
Selectivity in the N- and/or C-Alkylation of Schiff Bases Catalyzed by Crown Ether
Authors: Akabori Sadatoshi , Ohtomi Michiko , Shimada Kazuhide , Takemura Ayami 
Published: July 2006

Abstract
The reaction of anions derived from Schiff bases (N-(α-methylbenzylidene)aniline and N-cyclohexylideneaniline) with ethyl iodide or diethyl sulfate in aprotic solvents, in the presence of 18-crown-6, is found to give a high ratio of N⁄(N+C) or C⁄(N+C) alkylation when conducted in benzene or in dioxane.
Reduction of Ketones and Aldehydes via Catalytic Hydrosilylation Using Triethoxysilane and Trimethoxysilane
Authors: Matsumoto Hideyuki , Hoshino Yoshikazu , Nagai Yoichiro 
Published: July 2006

Abstract
It was found that ketones and aldehydes can be effectively reduced via catalytic hydrosilylation using triethoxysilane and trimethoxysilane in the presence of RhCl(PPh3)3 or RuCl2(PPh3)3, followed by ethanolysis or methanolysis.
An MO Study of the Reaction Mechanism of Photoisomerization from Isoxazole via Azirine Intermediate to Oxazole
Authors: Tanaka Hidetsugu , Osamura Yoshihiro , Matsushita Toshio , Nishimoto Kichisuke 
Published: July 2006

Abstract
The reaction mechanism of photoisomerization of isoxazoles and the wavelength dependent photochemistry of azirine intermediates which are the photoisomerization reaction intermediates are investigated theoretically by means of ab initio MO-CI calculation. The present calculation shows that the lowest excited singlet state, S1, of azirine intermediate is an (n→π*) state localized at the carbonyl chromophore, while the S2 state is assigned to be an (n→π*) state localized at the ketimine chromophore. Intersystem crossing from S1 to T1 states of azirine intermediate causes the N-C bond rupture of azirine ring and leads to isoxazole. On the other hand, azirine intermediate in the S2 state proceeds to the C-C bond break of azirine ring and converts to oxazole via intersystem crossing to the T1 state.
Synthetic Inorganic Ion-exchange Materials. XXXI. Ion-exchange Behavior of Tervalent Metals and Rare Earth Elements on Crystalline Antimonic(V) Acid Cation Exchanger
Authors: Abe Mitsuo , Tsuji Masamichi , Kimura Masato 
Published: July 2006

Abstract
The increasing order of ion-exchange selectivity for tervalent metal ions: Al3+&lt;&lt;Ga3+≤Yb3+&lt;Fe3+&lt;La3+&lt;In3+, was established in 1 mol dm−3 nitric acid solution on a crystalline antimonic(V) acid (C-SbA) cation exchanger. Strong correlation was found between the selectivity and the effective ionic radii of these ions. Large separation factors for neighboring ions were obtained, as compared with the commercial ion exchange resin. An effective separation of aluminium(III)-iron(III) ion pairs and a group separation of garium(III) and ytterbium(III) ions from lanthanum(III) ion were performed by using a relatively small C-SbA column (4 cm× 0.4 cm i.d.).
A Sandwich Photocell Using Chlorophyll Electrodes
Authors: Takahashi Fujio , Komori Tetuo 
Published: July 2006

Abstract
A sandwich-type photocell was made by placing an electrolyte between two electrodes. A transparent electrode, a glass plate coated with In2O3, was used for one electrode. A mixture of chlorophyll and 2-(cis-10-heptadecenyl)-6-methoxy-p-benzoquinone was spread onto this transparent electrode. A Pt plate covered by chlorophyll or a mixture of chlorophyll and riboflavin tetrabutyrate was used as the other electrode. The electrolyte contained flavin mononucleotide in a phosphate buffer. The potential difference between the two electrodes was 314 mV and the maximum photovoltage under illumination was 176 mV. The photocell is compact and can produce a photocurrent for more than 90 h.
Heterogeneous Reactions of Nitrogen Monoxide on Titanium Dioxide Photocatalysts in Solutions
Authors: Yoneyama Hiroshi , Shiota Hisashi , Tamura Hideo 
Published: July 2006

Abstract
Heterogeneous reactions of nitrogen monoxide on illuminated TiO2 catalysts in 1 mol dm−3 HClO4 were studied by electrochemical analysis. Nitrogen monoxide was reduced to ammonia and hydrazine. The main reaction was found to be a chemical reaction of hydroxylamine as a reaction intermediate with nitrogen monoxide to give molecular nitrogen. Nitrate was detected as an oxidation product formed by the counterpart reaction of the reduction of nitrogen monoxide.
Crystal and Molecular Structure of Antibiotic Gilvocarcin M
Authors: Hirayama Noriaki , Takahashi Keiichi , Shirahata Kunikatsu , Ohashi Yuji , Sasada Yoshio 
Published: July 2006

Abstract
The structure of gilvocarcin M, C26H26O9, an antibiotic with a novel carbon skeleton, has been determined by single crystal X-ray analysis. The space group is P21 with a=15.063(5), b=16.162(4), c=4.905(2) Å, β=91.47(3)°, and Z=2. The structure was solved by direct methods, and least-squares refinement using 1734 reflexions gave the final R value of 0.054. The title compound is composed of a unique aglycone and a fucofuranose, which are linked together through a C–C glycosyl linkage. The furanose ring takes the °E conformation.
Formation of Zn-bearing Ferrite by Air Oxidation of Aqueous Suspension
Authors: Kanzaki Tadao , Nakajima Jun-ichiro , Tamaura Yutaka , Katsura Takashi 
Published: July 2006

Abstract
Zn-bearing spinel ferrites were obtained by air oxidation of the iron(II) hydroxide suspension of the mole fraction Zn(II) to [Zn(II)+Fetotal], rZn, ranging from 0.029 to 0.33 (except for 0.057) at pH 10.0 and 65 °C, but at rzn=0.057 only α-FeOOH was formed. The Zn-bearing spinel ferrite obtained at rZn=0.33 has the normal spinel structure. At pH 8.0, the Zn-bearing spinel ferrite is obtained at rZn=0.057, but the spinel ferrite is slightly oxidized to γ-Fe2O3.
Selective Oxidation of Unsymmetrical Thiosulfinic S-Esters to the Corresponding Thiosulfonic S-Esters with NaIO4
Authors: Takata Toshikazu , Kim Yong Hae , Oae Shigeru 
Published: July 2006

Abstract
Unsymmetrical thiosulfinic S-esters were oxidized with sodium metaperiodate in aqueous media to the corresponding unsymmetrical thiosulfonic S-esters nearly quantitatively. The oxidation was accelerated by addition of a catalytic amount of inorganic and organic acids or halogen. Sulfinic esters were produced competitively along with the thiosulfonic S-esters in the oxidation of thiosulfinic S-esters in aqueous alcohol. However, unsymmetrical disulfides were not oxidized selectively to the corresponding unsymmetrical thiosulfonic S-esters but a mixture of both symmetrical and unsymmetrical thiosulfonic testers was obtained.
Synthesis and Properties of Bridgehead-substituted Bicyclo[n.2.2] Bridgehead Alkenes
Authors: Sakai Yasuo , Toyotani Shingo , Ohtani Masaru , Matsumoto Masaharu , Tobe Yoshito , Odaira Yoshinobu 
Published: July 2006

Abstract
The bridgehead-substituted bicyclo[n.2.2] bridgehead alkenes (1b–3b) (1, n=4; 2, n=5; 3, n=6; b, R=OAc) were synthesized based on the oxidative decarboxylation of [n.2.2]propellanecarboxylic acids with lead tetraacetate. The parent alkene (1a–3a) (a, R=H) and other bridgehead-substituted derivatives (1c–3c and 1d–3d) (c, R=OH; d, R=Cl) were prepared from 1b–3b. The examination of the 13C NMR chemical shifts of 1a–c, 2a–c, and 3a–c indicates the presence of electronic interaction between the bridgehead double bond (Cγ) and the opposite bridgehead carbon (Cα), being the homoallylic position of the double bond. From the product study and the kinetic results of the solvolysis of the bridgehead chlorides 1d–3d, it is indicated that the homoallylic participation of the strained bridgehead double bond to the carbonium ion center located at the opposite bridgehead position operates in the solvolysis of 1d and 2d. It may be, therefore, concluded that highly strained bridgehead alkenes, especially, bicyclo[4.2.2]decene system, show remarkable homoallylic type α, γ-interaction both in the ground state and in the transition state (carbonium ion).
Chemistry of Dienyl Anions. IV. Geometry of Pentadienyl Anions in Solution and in the Solid State Determined by Regioselective Trimethylsilylation and NMR
Authors: Yasuda Hajime , Yamauchi Michihide , Ohnuma Yasuo , Nakamura Akira 
Published: July 2006

Abstract
The configurational analysis of a series of alkyl substituted pentadienyl anions in THF was examined by trimethylsilylation and from the variable temperature 1H- and 13C-NMR spectra. Potassium pentadienide, -2-methylpentadienide or -2,4-dimethylpentadienide produced preferentially (Z)-2,4-pentadienyltrimethylsilane or its methyl substituted analogues to indicate that these compounds have the “U”-shaped structure in solution. By contrast, trimethylsilylation of potassium pentadienide and -2-methylpentadienide in the crystalline state produced the (E)- and the (E),(Z)-isomers, respectively, suggesting that the geometry is drastically changed to the “W”- or “S”-shaped by the medium effect. The W-shaped structure of potassium 3-methylpentadienide in THF and in the solid state is exceptional. Geometry of trapped products of potassium cycloheptadienide and -cyclooctadienide is also (Z) but the silylation occurred on the central carbon in contrast to the terminal silylation seen for the open-chain pentadienides. Geometry of these dienyl anions determined by NMR below −30 °C was consistent with the result obtained from trimethylsilylation. Superficial conflict between MINDO/3 prediction and the experimental evidence was reasonably reconciled by considering contact ion pairs for potassium pentadienide in THF and more strongly-solvated ion pairs for the lithium analogues.
The Use of Grignard Reagents in the Synthesis of Carbohydrates. III. The One-way Anomerization of Methyl Glycofuranosides and the Opening of Their Furanose Rings
Authors: Kawana Masajiro , Kuzuhara Hiroyoshi , Emoto Sakae 
Published: July 2006

Abstract
The anomerization of methyl glycofuranoside derivatives with methylmagnesium iodide or t-butylmagnesium bromide occurred in a one-way manner. For example, methyl 5-O-benzyl-β-d-ribofuranoside (3β) was converted into the corresponding α-anomer (3α) in a 95% yield when a mixture of 3β and t-butylmagnesium bromide in benzene–ether was heated at about 75 °C to remove the ether; the reverse reaction (from 3α to (3β) did not proceed. The reaction of 3β with methylmagnesium iodide gave open-chain products (33%), besides 3α (30%). Twenty kinds of anomers were tested, and the mechanisms of the reactions were discussed. The cleavage of a benzyl- or trityl-protecting group with the Grignard reagent was also observed during the reaction.
Structural Study of Optical Resolution. IX. The Crystal Structure of (−)589-Tris(biguanide)cobalt(III) Chloride d-Tartrate Pentahydrate
Authors: Tada Toshiji , Kushi Yoshihiko , Yoneda Hayami 
Published: July 2006

Abstract
The crystal structure of the less-soluble diastereomeric salt, (−)589-[Co(Hbg)3]Cl(d-tart)·5H2O, has been determined by X-ray analysis (R=0.056, 1277 reflections). The crystals are orthorhombic, with the space group of C222, Z=4, a=24.846(5), b=12.970(2), and c=8.645(2) Å. The main features of the crystal structure are as follows: (1) The complex cation and Cl− anion are arranged alternately along the b-axis to form an infinite spiral chain. The distances between N(Hbg) and Cl are 3.452 and 3.376 Å. (2) The tartrate ions exist as a dimeric unit whose structure closely resembles that of [Sb2(d-tart)2]2−. Through the center of this dimeric unit pass three mutually orthogonal twofold axes. (3) There are short contacts between the Hbg ligands and the tartrate ions along the twofold axis of the complex; N(A2)···OT3 2.862, N(B2)···OT2 3.116, N(B3)···OT2 2.754, and N(B4)···OT1 2.963 Å. On the basis of these features, the chiral discrimination mechanism is discussed.
Transmission of Low-energy Electrons through Thin-films of Benzene and Hexane at 80 K
Authors: Hiraoka Kenzo , Nara Masaji 
Published: July 2006

Abstract
Transmission spectra of low-energy electrons (0–15 eV) for 10–100 Å films of benzene and hexane have been measured at 80 K. Resonances are clearly indicated by electron current It transmitted through the dielectric as a function of the incident electron energy Vi displayed as dIt⁄dVi vs. Vt. When the film thickness of hexane was increased, the height of the first peak (due to injection of electrons in the film) decreased drastically and a second peak appeared and grew strongly. From the energy of the second peak, the bulk electron affinity (–V0) of thin film was estimated. The V0 values for hexane and octane are 0.9 and 1.0 eV, respectively.
The Crystal and Molecular Structure of Grayanotoxin XIX. A New Minor Diterpene from Leucothoe Grayana Max.
Authors: Furusaki Akio , Gasa Shinsei , Ikeda Ry\={u}z\={o} , Matsumoto Takeshi , Yasuoka Noritake , Matsuura Yoshiki 
Published: July 2006

Abstract
The molecular structure of grayanotoxin XIX, C20H30O3, has been determined by means of X-ray crystal analysis. The crystals are triclinic, with two molecules in a unit cell with dimensions of a=10.406, b=10.648, c=8.003 Å, α=90.00, β=94.25, and γ=102.76°; the space group is P1. 2671 unique intensity data were collected on a four-circle diffractometer with Ni-filtered Cu Kα radiation. The structure was elucidated by the Monte Carlo direct method, using the 50 strongest reflections as the starting set. The block-diagonal least-squares refinement reduced the R value to 0.038. The structure obtained corresponds to 14-deoxygrayanotoxin VII. The two independent molecules exist in different conformations: one has a half-chair A-ring, and the other, an envelope A-ring. In both molecules, the B-ring takes a conformation intermediate between the chair and twist-chair forms, and the C-ring adopts a boat conformation. The crystal consists of infinite hydrogen-bonded molecular chains along the c axis.
Brillouin Scattering Study of Clathrate Hydrate Formation in Acetone–Water Solution
Authors: Kato Tadashi , Yudasaka Masako , Fujiyama Tsunetake 
Published: July 2006

Abstract
Light scattering spectra have been observed for binary solutions of acetone and water at 24, 34, and 44 °C in the concentration range of 0≤xAC≤0.25, where xAC is the mole fraction of acetone. The hypersonic velocities and the adiabatic compressibilities at 4.5 GHz were obtained from the observed values of Brillouin shifts. The observed concentration and temperature dependencies of the adiabatic compressibility were interpreted by assuming the existence of clathrate hydrate-like local structures in the solutions. The adiabatic compressibilities for binary solutions of t-butyl alcohol (TBA) and water were used as reference data. A comparison is made between the local structure formed in the acetone–water solution and that in the TBA–water solution.
Temperature Dependence of Thermal Positive Ion Production through Dissociation of Polyatomic Molecules
Authors: Kawano Hiroyuki , Hidaka Yoshiaki , Suga Masao 
Published: July 2006

Abstract
The production of a thermal positive ion (M+) from a polyatomic molecule (MX) incident upon a heated metal surface is investigated theoretically as a function of surface temperature (T). The quantitative expression of the ion emission current (i+) of M+ at a constant incident flux (N) of MX is found to change according to the condition whether the work function (φ) of the surface is higher or lower than the first ionization energy (I) of M and also to the degree of dissociation (γ) of MX on the surface. Namely,
(Remark: Graphics omitted.)
Here D is the bond dissociation energy of MX and K′s are virtually independent of T. In any other cases i+ cannot be expressed in such a simple form. The particular temperature regions corresponding to γ≈1 or γ&lt;&lt;1 are evaluated for given sets of N, D, I, and φ.
Electrochemical Fixation of Molecular Nitrogen on p-Type Gallium Phosphide Photocathode
Authors: Koizumi Masashi , Yoneyama Hiroshi , Tamura Hideo 
Published: July 2006

Abstract
Electrochemical fixation of molecular nitrogen to ammonia and hydrazine at p-type GaP photocathodes was studied in nonaqueous electrolytes containing either one of titanium tetraisopropoxide, titanium trichloride, vanadium trichloride, or chromium trichloride and a trace amount of water. Positive evidences for the nitrogen fixation were obtained in these electrolytes, but the current efficiency was quite low, and usually less than 1%. It is suggested from the present study that there are a variety of choices of electrolyte systems for the nitrogen fixation.
The σ-Bonded Palladium(II) Complexes of 2-Aryl-4,4-dimethyl-2-oxazolines
Authors: Izumi Takeo , Watabe Hiroyuki , Kasahara Akira 
Published: July 2006

Abstract
Reactions of 2-phenyl-4,4-dimethyl-2-oxazoline with lithium tetrachloropalladate(II) and palladium(II) acetate give dichlorobis(2-phenyl-4,4-dimethyl-2-oxazoline,3-N)palladium(II) and a cyclopalladated binuclear complex, di-μ-acetato-bis[2-(4′,4′-dimethyl-2′-oxazolinyl)phenyl,1-C,3′-N)dipalladium(II), respectively. The latter complex is readily converted by a metathetical reaction with lithium chloride into its chloro-bridged analogue. The chloro-bridged complex reacts with triphenylphosphine to give the corresponding mononuclear σ-bonding palladium complex. All the complexes prepared in this study were characterized by means of IR and NMR spectroscopies.
Electron-transfer Reaction from Sodium Benzenethiolate to Acceptors Assisted by Photo-excited Tris(2,2′-bipyridine)ruthenium(II)
Authors: Miyashita Tokuji , Matsuda Minoru 
Published: July 2006

Abstract
The photo-excited tris(2,2′-bipyridine)ruthenium(II) (Ru(bpy)32+*) was effectively quenched by sodium benzenethiolate in acetonitrile (Stern-Volmer constant=4860 dm3 mol−1). The flash photolysis of a solution containing Ru(bpy)32+ and benzenethiolate (excitation wavelength (λ)&gt;480 nm) produced transient species absorbing ca. 510 nm; this species was identified as Ru(bpy)3+ and decayed with first-order kinetics with k=3.0 s−1. This slow decay of Ru(bpy)3+ implies that the back-electron-transfer reaction was suppressed. The decay of Ru(bpy)3+ was accelerated by the addition of water, suggesting the possibility of the reaction between Ru(bpy)3+ and water, though no H2 was detected. The steady irradiation of a solution containing Ru(bpy)32+, benzenethiolate, and an electron-acceptor produced the radical anion of the added acceptor, which was detected with ESR spectroscopy.
Conformational Change of Poly(l-lysine) by Sodium Octyl Sulfate as Studied by Stopped-flow Circular Dichroism Method
Authors: Takeda Kunio , Iba Akira , Shirahama Keishiro 
Published: July 2006

Abstract
Circular dichroism (CD) studies were made on the conformational changes of poly(l-lysine) (PLL) induced by sodium octyl sulfate (SOS). The conformation of PLL has a negative double maximum characterizing the α-helix in 4.0–6.0×10−3 mol/dm3 SOS solutions. At a higher concentration of SOS, PLL takes the β-structure, the random coil remaining below it. These conformational changes were followed by measuring ellipticities at 192, 207, and 221 nm according to a CD stopped-flow method. The rate constant was ca. 2.7×10−1 s−1 for the coil-helix transition, the transition rate from coil to β-structure being high depending on SOS concentration. The β-structure was attained by adding a small amount of 1-octanol to the α-helical PLL in 5.0×10−3 mol/dm3 SOS. The effect of the surfactant on the triphasic conformation changes is discussed in terms of hydrophobic environment.
The Isolation, Characterization, and Isomerization of cis- and trans-Bis(benzonitrile)dichloroplatinum(II)
Authors: Uchiyama Toshihiko , Toshiyasu Yoshio , Nakamura Yukio , Miwa Toshio , Kawaguchi Shinichi 
Published: July 2006

Abstract
The reaction of platinum(II) chloride with neat benzonitrile gave bis(benzonitrile)dichloroplatinum(II) as a mixture of cis and trans isomers in variable proportions, depending on the temperature. The geometry of the chromatographically separated isomers was identified on the basis of the dipole-moment and IR data. The 13C NMR spectra in CDCl3 also enabled us to discriminate between isomers in both chemical shift and coupling to the 195Pt of the cyanide carbon, the resonance peak of which was utilized to follow the isomerization. The rate constant (kc) for the cis-to-trans isomerization was found to be (3.8±0.3)×10−6 s−1 in CDCl3 at 25 °C, ten times larger than that [kt=(2.9±0.2)×10−7 s−1] of the reverse reaction. The equilibrium between cis and trans strongly favored trans in CDCl3 at 25 °C, whereas in benzonitrile the cis form was the dominant species at room temperature, while the trans form was dominant at higher temperatures.
13C NMR Spectra of Series of Bis(2,2′-bipyridine)cobalt(III) and Bis(1,10-phenanthroline)cobalt(III) Complexes
Authors: Utsuno Shunji , Yoshikawa Yuzo , Tatehata Akira , Yamatera Hideo 
Published: July 2006

Abstract
Twenty-eight cobalt(III) complexes of these types: [Co(LL)3]3+ and [CoXX(LL)2]n+ (LL=2,2′-bipyridine or 1,10-phenanthroline, and XX=2CN−, 2NO2−, ethylenediamine, 2NH3, glycinate ion, 2H2O, C2O42−, CO32−, 2SCN−, 2N3−, 2CH3COO−, 2Cl−, or 2Br−, were prepared, and their 13C NMR spectra were recorded. Most of the resonances in the complexes were assigned mainly by the technique of selective proton decoupling. In the bpy complexes, the chemical-shift difference between corresponding carbon atoms was the greatest in the C-6 and C-6′ pair. The phen complexes also gave parallel results. The main factor responsible for the chemical-shift differences of the C-6 and C-6′ pair is explained as resulting from the difference in σ-bonding ability between the pyridyl group and the ligand, X.