bluuebunny/crossref_metadata_2025 huggingface dataset:
Thermodynamics of the Adsolubilization Equilibrium of Rhodamine B by Surfactant-Modified Zeolites
Authors: Hayakawa Katumitu , Miyamoto Yukihiko , Kurawaki Junichi , Kusumoto Yoshifumi , Satake Iwao , Sakai Masashi
Published: September 2002

The adsolubilization of the cationic dye rhodamine B (RB) into the adsorbed layers of dodecyl- (DTAB) and tetradecyltrimethylammonium bromide (TTAB) on high silica mordenites (HSZ-1, HSZ-3) and P-type zeolite (PZ) was examined quantitatively. The adsolubilization constant for the HSZ-1/TTAB system was determined at temperatures from 10 to 40 °C. As the surfactant adsorption increased, the adsolubilization of RB by the zeolite/surfactant complexes was enhanced. Adsolubilization of RB by HSZ-3/surfactant complexes required a critical quantity of adsorbed surfactant, whereas the PZ/TTAB complex needed only a very small quantity of adsorbed TTAB to adsolubilize RB. Both the adsolubilization constant and the maximum capacity were calculated using a Langmuir-type equation, and the enthalpy and entropy changes were determined for the HSZ-1/TTAB mixed system. The difference in the adsolubilization mode of the three zeolite/surfactant complexes is discussed in relation to the aggregation mode of the cationic surfactant.
Hydrogen Bond Formations of 1-Aminoanthracene in the Ground and Excited Electronic States with Protic Solvent Molecules
Authors: Watanabe Satoshi , Kumagai Ken-ichi , Hasegawa Miki , Kobayashi Michio , Okubo Jun , Yoshinaga Tetsutaro , Hiratsuka Hiroshi , Hoshi Toshihiko
Published: September 2002

The absorption and fluorescence spectra of 1-aminoanthracene (AA) in various solvents have been compared with those of 1-dimethylaminoanthracene (DMAA). This comparison has demonstrated that the amino group of AA in the ground electronic state acts as a proton-acceptor to form the A-type hydrogen bond with alcohol, while that of AA in the excited electronic state acts as a proton-donor to form the B-type one. In the cyclohexane-ethanol mixed solvent, the solute-solvent configuration for the fluorescing excited state of AA changes with the ethanol concentration; it keeps the same type of hydrogen bond with ethanol as that (A-type) in the ground electronic state in the lower ethanol concentrations up to 0.2% and exhibits an intramolecular-like rearrangement of the A-type hydrogen bond into the B-type one in the ethanol concentration range of 0.2—1%. This hydrogen bond rearrangement occurs in cooperation with a bulk reorientation of solvent molecules in the range of 1—100%. AA forms the hydrogen-donor-acceptor-type excimer in the nonpolar fluid matrix of MP (a 1 : 1 mixed solvent of methylcyclohexane and isopentane) at low temperature.
Kinetic Stability of Azaborafullerene C58BN as Predicted by the Bond Resonance Energy Model
Authors: Aihara Jun-ichi , Ishida Toshimasa
Published: September 2002

The kinetic stability of a polyatomic molecule is very hard to judge. We utilized the bond resonance energy (BRE) model to estimate the kinetic stability of azaborafullerenes C58BN. In marked contrast to C58B2 and C58N2, all truncated icosahedron-shaped isomers of C58BN were found to lack chemically reactive substructures. On this theoretical basis, these isomers are presumed to be kinetically fairly stable even under harsh reactor conditions. This explains well why C58BN can be detected by mass spectrometry. At least some of the isomers will be isolated in macroscopic amounts in the near future.
Mononuclear Copper(II) Hydroxo Complex: Structural Effect of a 3-Position of Tris(pyrazolyl)borates
Authors: Fujisawa Kiyoshi , Kobayashi Takako , Fujita Kouyu , Kitajima Nobumasa , Moro-oka Yoshihiko , Miyashita Yoshitaro , Yamada Yasunori , Okamoto Ken-ichi
Published: September 2002

New mononuclear nitratocopper(II) complexes ([Cu(NO3){HB(3,5-iPr2pz)3}] (1) and [Cu(NO3){HB(3-tBu-5-iPrpz)3}] (3)) and a novel mononuclear hydroxocopper(II) complex ([Cu(OH){HB(3-tBu-5-iPrpz)3}] (4)) have been prepared. These complexes were characterized by X-ray analysis and IR, UV-vis, and EPR spectroscopies. Except for the dinuclear complex ([{Cu[HB(3,5-iPr2pz)3]}2(μ-OH)2] (2)), the complexes are mononuclear structures having square-pyramidal (1), trigonal-pyramidal (3), and distorted tetrahedral (4) geometry. In comparison with these structures and their physicochemical properties, the structural effects on the alkyl substitutions at the close 3-position in hydrotris(pyrazolyl)borates play an important role in modifying the coordination environment about a copper(II) center and their physicochemical properties.
Monitoring Hydrothermal Reactions on the Millisecond Time Scale Using a Micro-Tube Flow Reactor and Kinetics of ATP Hydrolysis for the RNA World Hypothesis
Authors: Kawamura Kunio
Published: September 2002

A new method for monitoring hydrothermal reactions on the millisecond time scale has been developed using a micro-tube flow reactor. The system was designed based on a high-pressure pump, a sample-loop injector, a narrow-bore size capillary, a cooling bath, back-pressure tubing, and a sampling port. Samples were analyzed using high-performance liquid chromatography. Kinetic analyses of the hydrolyses of adenosine 5′–triphosphate (ATP) and adenosine 5′–monophosphate (AMP) on the millisecond time range at 250—315 °C were demonstrated so as to evaluate the performance of the method. In conclusion, monitoring was successful for the hydrolysis of ATP and AMP in 2—50 ms using fused-silica capillary tubing with 0.015 and 0.025 mm inner diameter (ID). The method enables real-time monitoring of hydrothermal reactions in about 100-times shorter time range than other techniques. This paper proposes apparent rate constants and activation energy for the consecutive hydrolysis of ATP to adenine at high temperatures that were difficult to determine by a conventional batch method. On the basis of the rate constants, kinetics and mechanistic analyses of the step-wise decomposition of ATP were investigated from the viewpoint of the RNA world hypothesis under hydrothermal environments.
The Development of Carbon Nanotubes/RuO2·xH2O Electrodes for Electrochemical Capacitors
Authors: Ma Renzhi , Wei Bingqing , Xu Cailu , Liang Ji , Wu Dehai
Published: September 2002

Carbon nanotubes were refluxed with nitric acid to create acid sites on the surface. After such treatment, amorphous or nano-scale crystalline RuO2·xH2O can be adhered to the surfaces of carbon nanotubes by a simple method. RuO2·xH2O became more amorphous with decreasing the fraction of carbon nanotubes. The capacitance can be enhanced significantly by the adherence. When the weight fraction of RuO2·xH2O in the composite electrodes reached 75%, a specific capacitance of 560 F g-1 was achieved. On the other hand, carbon nanotubes/RuO2·xH2O capacitors exhibit excellent power delivery behavior. So the processing of carbon nanotubes/RuO2·xH2O composite electrodes is a new attempt to fabricate supercapacitors with both high energy and high power density.
Highly Sensitive Energy-Transfer Luminescence of the N,N′-Bis(2-hydroxybenzyl)-ethylenediamine-N,N′-diacetatoterbium(III) Complex in Aqueous Solution
Authors: Saito Shingo , Hoshino Hitoshi , Yotsuyanagi Takao
Published: September 2002

The luminescent properties of a terbium complex with a hexadentate ligand of N,N′-Bis(2-hydroxybenzyl)ethylenediamine-N,N′-diacetic acid (HBED) having a phenolate functional group as antenna moiety, have been investigated. The complex exhibits a high emission quantum yield (φ = 0.222, ex. 288 nm, em. 546 nm) with a long decay lifetime (τH2O = 1.2 ms) in aqueous solution, which indicates energy-transfer type emission. The number of metal-bound water molecules in the complex was determined to be q = 1.8. The triplet energy level was estimated based on the data of its low-temperature phosphorescence. The calibration graph for Tb(III) was linear over the range from 3 × 10-11 to 1 × 10-8 mol dm-3. A 3σ-blank detection limit of 3 ppt was achieved.
Highly Selective Solvent Extraction of Uranyl Ion Using Super Uranophiles in the Presence of Methyltrioctylammonium Chloride
Authors: Nishida Masashi , Kondo Hirotomo , Sonoda Miwako , Ishii Daido , Yoshida Isao
Published: September 2002

A highly selective solvent extraction of uranyl ion, UO22+, was carried out by using superuranophiles, i.e., hydroxycalix[n]arene-p-sulfonates, Hj1nn- (n = 6, j = 2; n = 8, j = 4), in aqueous solution in the presence of methyltrioctylammonium chloride, MTA+Cl-, in chloroform. In the present extraction, UO22+ in the aqueous phase reacted first selectively and quantitatively with Hj1nn- to form a complex, (UO216H-3)9- or ((UO2)218H-3)11-, respectively. Then, the resultant complexes combined with MTA+ to form hydrophobic and electrically neutral ionic associates, (MTA+)9 (UO216H-3)9- or (MTA+)11 ((UO2)218H-3)11-, and were extracted quantitatively into chloroform. No interference by the coexisting-metal ions was observed. The presence of a large amount of chloride and carbonate ions decreased the extractability of UO22+. The extracted UO22+ was recovered by the stripping method using 2 M sulfuric acid, retaining Hj1nn- in the chloroform phase as a MTA+ associates. The organic phase could be repeatedly used for subsequent extractions.
Optically Active S-Bridged CoIIIPdII Polynuclear Complexes Derived from ΔΔ-[Ni{Co(aet)2(R-pn)}2]4+(aet = 2-Aminoethanethiolate, R-pn = (R)-1,2-Propanediamine)
Authors: Yamada Yasunori , Maeda Yoko , Konno Takumi , Fujisawa Kiyoshi , Okamoto Ken-ichi
Published: September 2002

The substitution reaction of ΔΔ-[Ni{Co(aet)2(R-pn)}2]4+ with equimolar Na2[PdCl4] in water gave selectively an optically active trinuclear complex, ΔΔ-[Pd{Co(aet)2(R-pn)}2]4+ (1). On the other hand, an optically active dinuclear complex, Δ-[PdCl2{Co(aet)2(R-pn)}]+ (2), was also obtained by a two-molar equivalent addition of Na2[PdCl4] under the same reaction condition. Similarly, the reaction of ΔΔ-[Ni{Co(aet)2(R-pn)}2]4+ with two molar equivalent [Pd(NO3)2(bpy)] produced an optically active dinuclear complex, Δ-[Pd(bpy){Co(aet)2(R-pn)}]3+ (3). The crystal structures of complexes 1, 2, and 3 were determined by X-ray crystallography. Each of the Co atoms in 1, 2, and 3 is coordinated by two aet and one R-pn ligands to take an approximately octahedral geometry. The Pd atom in 1 is coordinated by four S atoms from two cis(S)-[Co(aet)2(R-pn)]+ units. The Pd atom in 2 is ligated by two S atoms from one cis(S)-[Co(aet)2(R-pn)]+ unit and two Cl atoms, while the Pd atom in 3 is coordinated by two S atoms from one cis(S)-[Co(aet)2(R-pn)]+ unit and two N atoms in bpy. All of the Pd atoms in 1, 2, and 3 take an almost square-planar geometry. These complexes are also characterized on the basis of the electronic absorption, CD, and 13C NMR spectra. The interconversions of the trinuclear and dinuclear complexes obtained in this work are discussed.
Spectroscopic and Electrochemical Properties of Cytochrome c551 from Alcaligenes xylosoxidans GIFU 1051
Authors: Deligeer  , Kataoka Kunishige , Yamaguchi Kazuya , Suzuki Shinnichiro
Published: September 2002

Spectroscopic and electrochemical characterizations of cytochrome c551 from a denitrifying bacterium, Alcaligenes xylosoxidans GIFU 1051, have been performed. The spectral data indicate that the oxidized and reduced proteins have a six-coordinate low-spin heme. The fast electron-transfer process from cytochrome c551 to cognate Cu-containing nitrite reductase was electrochemically observed.
Adsorption of Tetravalent Metal Ions to Chelating Resins Containing Iminodiacetic Acid Groups
Authors: Yuchi Akio , Yoshida Norihito
Published: September 2002

With respect to the selectivities, the compositions of species formed by the adsorption of tetravalent metal ions (M4+) to chelating resins containing iminodiacetic acid groups (-LH2) were estimated from the shapes of the adsorption curves and the infrared absorption spectra of the polymer complexes: [-LM(OH)2] for Zr4+ and Hf4+, while [(-LH)4M], [(-L)(-LH)2M], and [(-L)2M] for Th4+.
Crystal Structure and Spectrochemical Properties of a Dinuclear Palladium(II) Complex with 2,3,5,6-Tetra(2-pyridyl)pyrazine
Authors: Yamada Yasunori , Miyashita Yoshitaro , Fujisawa Kiyoshi , Okamoto Ken-ichi
Published: September 2002

A dinuclear Pd(II) complex bridged with 2,3,5,6-tetra(2-pyridyl)pyrazine (tppz) was newly obtained by the reaction of Pd(II) ion with tppz. The crystal structure of the dinuclear complex was determined by X-ray structural analysis. The spectrochemical properties of the complex are also discussed in relation to the stereochemical behavior.
Binding Interaction of the Trimethylsilyl Cation with Oxygen and Nitrogen Bases in the Gas Phase. Acetopheones, Benzaldehydes, Pyridines, Anilines, and N,N-Dimethylanilines
Authors: Mustanir  , Shimada Kenji , Ohta Fumio , Mishima Masaaki
Published: September 2002

The gas-phase basicities toward the trimethylsilyl cation, GB(Me3Si+), were determined for a series of acetophenones, benzaldehydes, pyridines, anilines, and N,N-dimethylanilines by measuring the equilibrium constants of trimethylsilyl cation transfer reactions. GB(Me3Si+) increases in the order aniline < benzaldehyde < acetophenone < N,N-dimethylaniline < pyridine, while GB(H+) increases as benzaldehyde < acetophenone < aniline < pyridine < N,N-dimethylaniline. The effects of ring substituents on the GB(Me3Si+) of the respective bases are, however, linearly correlated with the corresponding proton basicities with a slope of 0.8 to 1.0, showing family-dependent linear relationships. Furthermore, an analysis of the substituent effects on the GB(Me3Si+) of acetophenone and benzaldehyde showed that the ρ values are close to those for the proton basicities, though the resonance demand of Me3Si+ adduct ions is slightly reduced compared with that for the protonated ones. DFT calculations at the B3LYP/6-31+G(d) level of theory reproduced such a trend in substituent effects as well as the family-dependent linear correlations between the H+ and Me3Si+ basicities. Both the experimental and theoretical results lead to the conclusion that the binding interactions of Me3Si+ with O and N atoms of organic bases have a pronounced covalent character to a similar degree as that of a proton.
An Attempted Synthesis of 8-Shaped Circulene: Synthesis and Characterization of [2.2](4,4′)Biphenylo(3,11)dibenzo[c, l]chrysenophane and Its Cyclophadiene
Authors: Yano Koji , Osatani Mitsunobu , Tani Keita , Adachi Tomohiro , Yamamoto Koji , Matsubara Hiroshi
Published: September 2002

The syntheses of the title compounds are described. The unusually strained structures were supported by their 1H NMR spectra, electronic spectra, and X-ray crystallographic analyses.
Synthesis, Characterization, and Controlling Morphology of an Aryl Ether Dendrimer Containing a Dichalcogenide Bond as the Core
Authors: Takaguchi Yutaka , Suzuki Shinji , Mori Takahiro , Motoyoshiya Jiro , Aoyama Hiromu
Published: September 2002

A poly(benzyl ether) dendron with a thiol group or a selenocyanate group at the focal point was synthesized and well characterized, and then used for the controlling morphology. The molecules show a reversible redox behavior between dendrons and dendrimer dichalcogenides, being achieved under chemical reactions, although a dendrimer having selenium atoms has never been reported. Furthermore, dendrimer dichalcogenides underwent an dechalcogenation reaction upon a treatment with hexaethylphosphorous triamide or photoirradiation to give dendrimer chalcogenides.
Synthesis of 3-Ethoxyisoxazole Derivatives and 3-Ethoxy-1H-pyrazole Derivatives from β-Oxo Thionoesters
Authors: Ohta Tetsuo , Fujisawa Hironori , Nakai Yasuto , Furukawa Isao
Published: September 2002

3-Ethoxyisoxazoles and 3-ethoxy-1H-pyrazoles were obtained in high yields from β-oxo thionoesters. The reaction of the ethyl β-oxo thionoesters with hydroxylamine hydrochloride in the presence of triethylamine at room temperature for 2 h gave the ethyl 3-oxopropiohydroximates and their hemiacetals, which were easily converted to the 3-ethoxyisoxazoles by refluxing for 3 h at pH 3—5. On the other hand, the reaction of the ethyl β-oxo thionoesters with hydrazine derivatives in the presence of triethylamine for 3—8 h at room temperature directly yielded the 3-ethoxy-1H-pyrazoles.
Synthesis, Properties, and Redox Behaviors of Di- and Trications Composed of Di(1-azulenyl)methylium Units Connected by p- and m-Phenylene and 1,3,5-Benzenetriyl Spacers
Authors: Ito Shunji , Morita Noboru , Asao Toyonobu
Published: September 2002

The titled stable di- and trications composed of di(1-azulenyl)methylium units connected by p- and m-phenylene and 1,3,5-benzenetriyl spacers, i.e., 1,3- and 1,4-phenylenebis[bis(3-methyl- and 3,6-di-t-butyl-1-azulenyl)methylium] bis(hexafluorophosphate)s (4a, 4b·2PF6- and 5a, 5b·2PF6-), and 1,3,5-benzenetriyltris[bis(3,6-di-t-butyl-1-azulenyl)methylium] tris(hexafluorophosphate) (6·3PF6-), were prepared by hydride abstraction of the corresponding hydrocarbons. In spite of di- and tricationic structures, 4a, 4b, 5a, 5b, and 6 showed high stabilities with large pKR+ values due to the effects of 1-azulenyl substituents. The two cation units in the dications 4a, 4b and 5a, 5b were neutralized simultaneously at the pH of 11.2—12.1 ± 0.2. The pH correspond to the average of the pKR+ values of dications and half-neutralized monocations. 3,6-Di-t-butyl substituents on 1-azulenyl groups increased solubilities and reversibilities of both reduction and oxidation upon cyclic voltammetry (CV). In contrast to the dications, the three cation units in the trication 6 were neutralized stepwise at the pH of 9.1 ± 0.2, 10.9 ± 0.2, and 12.7 ± 0.2, respectively. The electrochemical oxidation of di- and trications 4b, 5b, and 6 exhibited a reversible wave at +0.87— +0.89 V (V vs. Ag/Ag+) upon CV, although dications 4a and 5a showed irreversible waves in the similar potential ranges. The electrochemical reduction of m-phenylene-connected dications 4a and 4b showed two very closely spaced reduction waves at -0.65— -0.82 V upon CV. In the case of p-phenylene-connected dications, 5a and 5b showed a one-step, two-electron reduction wave at -0.47 and -0.55 V, respectively, upon CV. The reduction wave corresponds to the formation of an unstable closed-shell molecule. The reduction of trication 6 showed irreversible waves in the potential ranges similar to those of dication 4b.
A Facile Synthesis of Novel Liquid Crystalline Materials Having a Trifluoromethoxy Group and Their Electro-Optical Properties
Authors: Kanie Kiyoshi , Takehara Sadao , Hiyama Tamejiro
Published: September 2002

Novel liquid crystals (LCs) containing a trifluoromethoxy group connected to a cyclohexane mesogen or to an alkyl tail were prepared through an oxidative desulfurization-fluorination reaction of the corresponding dithiocarbonates. They were compared with LCs containing a methoxy group with respect to phase transition behavior and physical and electro-optical properties. Most of the CF3O-substituted LCs exhibited in a wide range of temperatures LC phases depending on the type of a mesogenic structure. LCs with a trifluoromethoxycyclohexane mesogen were shown to be thermally more stable than the LCs with a trifluoromethoxybenzene mesogen. LCs having a trifluoromethoxyalkyl tail show physical and electro-optical properties favorable to materials for not only TN-LCDs but TFT-addressed TN-LCDs. Furthermore, 3-β-CF3O-substituted cholestane was shown to be a potential chiral dopant for TFT-addressed TN-LCDs.
Structural Elucidation of 1,3-Phenylenebis(methylene)-Bridged Calix[6]arenes with Four Uncapped Hydroxy Groups
Authors: Saiki Toshiyuki , Akine Shigehisa , Goto Kei , Tokitoh Norihiro , Kawashima Takayuki , Okazaki Renji
Published: September 2002

1,3-Phenylenebis(methylene)-bridged calix[6]arenes with four uncapped hydroxy groups at the lower rim and various kinds of functionalities on the bridging unit were synthesized. Their structures in solution and in the crystalline state were determined by NMR spectroscopy, molecular mechanics calculations, and X-ray crystallographic analyses. They were found to adopt a pinched cone conformation, where the bridging 1,3-phenylenebis(methylene) unit lies below in such a way that it forms the bottom of the cone. There is a strong intramolecular hydrogen bonding network forming a cyclic array in these molecules; this network is considered to play an important role in the stabilization of the pinched cone conformation. The conformational mobility of the bridging unit was also investigated. It was found that the steric demand of the central functionality has a great influence on the swinging motion of the bridging unit.
Electrochemical Growth and Charge-Transport Properties of Polyaniline/Poly(styrenesulfonate) Composite Films
Authors: Komura Teruhisa , Mori Kouji , Yamaguchi Takahiro , Takahashi Kousin
Published: September 2002

The kinetic parameters of charge transport in composite-modified electrodes were measured as a function of the electrode potential, film thickness, solution pH, and counter ion composition by electrochemical impedance spectroscopy. The impedance characteristics of composite films were analyzed on the basis of the diffusion-migration transport of both holes and protons in the film. Incorporation of the polyanion with the host matrix produced a more compact deposite. A slow growth of the composite film during electropolymerization was ascribed mainly to its low electronic conductivity caused by poor contacts among polyaniline chains. Poly(styrenesulfonic acid) lowered the coupled diffusion coefficient of the charge carriers by a factor of ten. The relationships between the kinetic parameters and the oxidation and protonation levels of polyaniline suggested that the rate of charge transport through the composite film was controlled by electron transport, which occurred probably via interchain electron hopping.
Tributylmanganate(II)-Mediated Cyclization of Enynes
Authors: Usugi Shinichi , Shinokubo Hiroshi , Oshima Koichiro
Published: September 2002

Treatment of enynes with tributylmanganate(II) provided cyclized products containing alkylidene substituents. 1-Tridecen-6-yne or 1-tetradecen-7-yne gave 1-heptylidene-2-methylcyclopentane or 1-heptylidene-2-methylcyclohexane in 67 or 50% yield, respectively upon treatment with tributylmanganate(II). The reaction of dimethylvinylsilyl ether of 3-decyn-1-ol with tributylmanganate(II) afforded 4-heptylidene-2,2,3-trimethyl-1-oxa-2-silacyclohexane in good yield.
Hydration Properties of an Amino Sugar-Containing Synthetic Polymer by DSC and NMR Spectroscopy
Authors: Hirata Yuichi , Nakagawa Tsutomu
Published: September 2002

Poly(D-glucopyranosyl-α(1 → 6)-2-deoxy-2-methacrylamido-D-mannitol-co-D-glucopyranosyl-α(1 → 6)-2-deoxy-2-methacrylamido-D-glucitol) (poly(MAGPM-co-MAGPG)) was prepared by radical polymerization from methacrylamide monomers which were synthesized by the methacryloylation of amino sugars. The fraction of a different state of water in poly(MAGPM-co-MAGPG) was determined using DSC. The temperature dependence on the chemical shift of the 1H NMR was different between the low and high water retentions. The 17O spin-lattice relaxation time of water in poly(MAGPM-co-MAGPG) was compared to that of glucose, Palatinit®, and PVA. The interaction between the water and the hydroxy groups in poly(MAGPM-co-MAGPG) is strongly affected not only by the mobility of the sugar side chain, but also by the highly concentrated hydroxy groups along the hydrophobic main chains. The sugar side chain in poly(MAGPM-co-MAGPG) has a considerably higher hydration ability in comparison with glucose, Palatinit®, and PVA, although these substances have a hydroxy group as a hydrophilic group in common.
Reversible Control of the Pitch of Cholesteric Liquid Crystals by Photochromism of Chiral Fulgide Derivatives
Authors: Sagisaka Toshiya , Yokoyama Yasushi
Published: September 2002

When an enantiomer of resolved indolylfulgide (1) or either of the (R)-binaphthol-condensed indolylfulgides (2, 3) was mixed with a nematic liquid crystal (5CB), the cholesteric phase was induced. Their cholesteric pitches were reversibly changed by photoirradiation. Whereas the twisting ability of the cholesteric pitch (βM) was larger for the colorless form than for the colored form in the case of 1, it was larger for the colored form than for the colorless form in the cases of 2 and 3. In addition, βM of 1 is generally smaller than that of 2 and 3. These phenomena were explained in terms of the helical conformation of the hexatriene moiety of fulgides and the chirality of the binaphthol moiety.

The cholesteric sense of a fulgide-doped liquid crystal was changed between plus and minus reversibly by the pre-doping of the chiral formaldehyde acetal of 1,1′-bi-2-naphthol ((S)-4).
Preparation of Fibrous TiO2 Material Using an Organogelator
Authors: Kobayashi Satoshi , Hanabusa Kenji , Suzuki Masahiro , Kimura Mutsumi , Shirai Hirofusa
Published: September 2002

A TiO2 material with a fibrous structure was prepared using an organogelator, Z-L-Ile-NHC18H37, as a structure-forming agent for the sol-gel polymerization of titanium tetraisopropoxide, Ti[OCH(CH3)2]4. Z-L-Ile-NHC18H37 is an excellent gelator that can harden metal alkoxide, mainly by forming intermolecular hydrogen-bonds. The gelling phenomenon is attributed to the formation of a three-dimensional network based on fibrous aggregates in organic fluids. When Z-L-Ile-NHC18H37 is used as a structure-forming agent for sol-gel polymerization, the unique structure of the fibrous TiO2 material is created by the hydrogen-bonds between the fibrous gelator aggregates and oligomeric titanias in the sol-gel polymerization system.
High Magnetic Field Effects on Interdigitated Microarray Electrodes
Authors: Nishiyama Satoko , Aogaki Ryoichi
Published: September 2002

High magnetic field effects were determined for a typical electrochemical reaction, the oxidation of hexacyanoferrate(II) to hexacyanoferrate(III) on interdigitated microarray electrodes. A characteristic dependence on the magnetic field direction was observed. Using a unique feature of the microarray electrode, an attempt was made to obtain a new method to analyze the components of the flux, and a hopeful way was shown to apply these microarray electrodes in a magnetic field.
Continuously Changing the Conformational Dependence of Saponite Hybrid Materials on the Intercalation Degree: Electric Linear Dichroism of Stilbazolium Derivatives Intercalated in Saponite Clay
Authors: Sasai Ryo , Shichi Tetsuya , Gekko Kunihiko , Takagi Katsuhiko
Published: September 2002

The molecular alignmet of 2- and 4-[4-(dimethylamino)styryl]-1-ethylpyridinium cations (2- and 4-DASEP, respectively) adsorbed on saponite clay and suspended in N,N-dimethylformamide (DMF) has been investigated by the electric linear dichroism (ELD) method. An ELD analysis of the saponite clay complex involving 4-DASEP molecules in DMF indicated that although the tilt angle of the 4-DASEP molecular plane increased considerably from 14.1 to 32.1°, the roll angle remained constant at ca. 31°, with a coverage of 10 to 100% of 4-DASEP molecular in saponite. In contrast, the tilt and roll angles of the corresponding positional isomer, 2-DASEP, on the clay surfaces slightly increased with the same coverage degrees. The change in tilt and roll angles in the 2- and 4-DASEP molecules may be significantly influenced by the structural variation of the guest molecules, especially the steric hindrance around the pyridinium N+ atoms. The conformational structure of the adsorbed stilbazolium cations in saponite is discussed based on these results.
Fabrication and Characterization of Meso-Macroporous Anatase TiO2 Films
Authors: Ito Seigo , Yoshida Shoichiro , Watanabe Tadashi
Published: September 2002

A porous TiO2 film possessing both meso-sized (2—50 nm) pores and macro-sized (100—300 nm) pores has been fabricated for the first time by coating an SnO2 substrate with a paste consisting of secondary TiO2 submicroparticles, poylethylene glycol, hydroxypropyl cellulose and water, followed by calcination. The macropores are formed most probably by phase separation between the TiO2 particles and the polymers in the course of drying of the coated paste. The meso-macroporous TiO2 film thus prepared has a thickness of ca. 10 μm by four-fold coating, and is characterized by a large surface area arising from the mesopores in the secondary TiO2 particles, and by the presence of wide channels within the film. The film fabricated by calcination at 550 °C for 30 min was composed of pure anatase with high crystallinity. These features are favorable to construct an electrode for dye-sensitized photoelectrochemical cells.
Enhanced Decomposition of Dichloromethane in Air by Multi-Pass Electron Beam Irradiation
Authors: Wahyuni Sri , Hirota Koichi , Hakoda Teruyuki , Arai Hidehiko , Hashimoto Shoji , Kawamoto Fumio , Mukunoki Yasuo
Published: September 2002

The decomposition of dichloromethane (CH2Cl2) in model air gases (concentration, around 100 ppm) by electron beam (EB) and γ-ray irradiation was studied using batch-type glass reactors of 500 ml volume. The addition effect of water on the decomposition was also investigated. In dry air, one-pass EB irradiation (10.7 kGy s-1) induced only 65% decomposition, even at 32 kGy, but the γ-ray irradiation (2 kGy h-1) or EB multi-pass irradiation (1.33 kGy s-1) decomposed CH2Cl2 100% at 32 kGy. Water addition (4 ml) enhanced the decomposition percentage to 96% at 16 kGy, even by one-pass irradiation. In dry air, the formation of CO2, CO, phosgene and chloroform was confirmed. The mechanism for the above addition effect was considered as well as for the multi-pass irradiation effect.
Synthetic Incorporation of Metal Complexes into Nucleic Acids and Peptides Directed toward Functionalized Molecules
Authors: Shionoya Mitsuhiko , Tanaka Kentaro
Published: September 2002

Novel synthetic approaches for incorporation of metal complexes into nucleic acids and peptides are described. First, novel artificial β-C-nucleosides bearing a chelator nucleobase (2-aminophenol, catechol, or o-phenylenediamine) have been synthesized. These artificial nucleobases were introduced for alternative base pairing through metal coordination instead of the hydrogen bonding in natural DNA. 1H NMR and mass spectral studies clearly showed that o-phenylenediamine-type nucleoside forms a stable 2 : 1 square-planar complex with a PdII ion, providing an alternative DNA base pairing through metal complexation. Secondly, an efficient strategy for the liquid-phase synthesis of cyclic metallopeptides having a repeating Gly-L-Cys(terpyPtII) sequence, cyclo[-Gly-L-Cys(terpyPtII)-]nCln (n = 3, 4), has been developed. These cyclic metallopeptides were obtained by cyclization of the corresponding linear peptides, H2[-Gly-L-Cys(terpyPtII)-]nOH·(CF3CO2)n+1 (n = 3, 4), in moderate yields. The former cyclic hexapeptide was found to act as a positively charged anion receptor. This synthetic approach would provide a powerful tool for arraying metal centers on cyclopeptide frameworks.
Classification and Prediction of Reagents' Roles by FRAU System with Self-Organizing Neural Network Model
Authors: Satoh Hiroko , Funatsu Kimito , Takano Keiko , Nakata Tadashi
Published: September 2002

The classification and prediction of the roles for reagents in reactions are presented. The same dimensional representation of various reagents independent of the number of atoms was achieved by selecting representative factors by the FRAU (Field-characterization for Reaction Analysis and Understanding) system. Training of a self-organizing model considering both negative and absent data was accomplished by modifying the original counter-propagation (CP) type of Kohonen neural network to treat absent data differently from negative data. The modified CP Kohonen neural network successfully classified the reagents and produced a reagent-roles correlation model that gives good answers predicting roles of the reagents.
Hydration Structure of Glycine Molecules in Aqueous Alkaline Solutions
Authors: Sugawara Kentaro , Kameda Yasuo , Usuki Takeshi , Uemura Osamu , Fukunaga Toshiharu
Published: September 2002

Time-of-flight (TOF) neutron diffraction measurements have been carried out on the alkaline aqueous 2 mol% glycine solution in heavy water. The isotopic substitution technique has been applied to both nitrogen and hydrogen atoms within glycine molecules in order to obtain information concerning the hydration structure around the amino- and methylene group in the glycine molecule under the high-pH condition. Results revealed that the nitrogen atom in the amino group forms a hydrogen bond of the N…D-O type with ca. one D2O molecule (rN…D = 1.97(3) Å, ∠N…D-O = 174(5)°), and simultaneously forms bonds of N-D…OD2 type with ca. two D2O molecules (rN…O = 2.92(3) Å) in the present alkaline aqueous solution. This behavior is in contrast to the hydration structure around the amino group in the glycine molecule reported for the neutral aqueous solution, in which the amino group forms the hydrogen bonds of N-D…OD2 type with ca. three D2O molecules. The first hydration shell around the methylene group in the glycine molecule involves ca. two D2O molecules per one glycine molecule. The orientational correlation between the methylene-hydrogen atoms and neighboring D2O molecules is weak.
Synthesis of a Phosphorylated Polypeptide by a Thioester Method
Authors: Kawakami Toru , Hasegawa Koki , Aimoto Saburo
Published: September 2002

A method for the synthesis of phosphorylated polypeptides was investigated through the synthesis of the phosphorylated cAMP response element binding protein 1 (19-106) amide, [Thr(PO3H2)69,71]-CRE BP1(19-106)-NH2, as a model compound. Three partially protected peptide segments: Boc-[Lys(Boc)23,46,48,54, Cys(Acm)27,32]-CRE BP1(19-56)-SCH2CH2CO-β-Ala-NH2, Fmoc-[Thr(PO3H2)69,71, Lys(Boc)77, Cys(Acm)79]-CRE BP1(57-83)-SCH2CH2CO-β-Ala-NH2, and [Lys(Boc)97,98,105,106]-CRE BP1(84-106)-NH2, were prepared by the Boc solid-phase method and were used as building blocks. The segment condensations were carried out sequentially by a thioester method in the presence of a silver compound, HOObt, and DIEA. The desired product was obtained in 19% yield, based on the C-terminal building block, after removal of all the protecting groups on the peptide. These results indicate that the thioester method is quite useful for the preparation of phosphorylated polypeptide even if it contains cysteine residues. One thing which remains to be improved is the efficiency of the method for the preparation of partially protected peptide thioesters, which contain phosphorylated amino acid residues.
Production of Negative Ions from Fluorocarbons and Reaction Mechanism
Authors: Nakagawa Seiko , Shimokawa Toshinari
Published: September 2002

The temperature dependence of the formation of negative ions from C6F6, C5F5N, C6F5CN, C6F5CF3, and C6F5C6F5 was studied by using negative chemical ionization mass spectrometry. Parent negative ion and fragment ions: F- and (M-F)- (M = Parent Molecule) were observed. Secondary product ions: C5F4- and C5F2- for C6F6 and C5F6N- and C4FN- for C5F5N were also observed at temperatures higher than 523 K. A cluster of the parent molecule and F- is produced for C6F6 and C5F5N. The intensity of parent negative ions increases, while that of fragment ions and secondary ions decreases with decreasing temperature. Such results show that electron detachment from the parent anions will occur. Geometry of parent negative ions and cluster anions of C6F6, C5F5N, C6F5CN, and C6F5CF3 were also calculated using the Hartree-Fock method. The structure and the distribution of the spin density are almost the same for all these molecules. This similarity means that the production of negative ions from them and the reaction mechanisms are almost the same.
Chiral Replacement Criterion for Characterizing Holotopic and Hemitopic Relationships
Authors: Fujita Shinsaku
Published: September 2002

A chiral replacement criterion has been proposed to characterize stereochemical equivalence. This criterion is effective to determine holotopic and hemitopic relationships, which are sub-relationships of a homotopic relationship. The criterion has been shown to be complementary to the membership criterion based on the sphericity concept.
Heat Capacities of Isomeric 2-Butoxyethanols from 13 to 300 K: Fusion and Glass Transition
Authors: Atake Tooru , Kawaji Hitoshi , Tojo Takeo , Kawasaki Koji , Ootsuka Yasushiro , Katou Maki , Koga Yoshikata
Published: September 2002

We measured the heat capacities of 2-butoxyethanol (abbreviated as nBE), 2-isobutoxyethanol (iBE) and 2-t-butoxyethanol (tBE) from 13 to 300 K by adiabatic calorimetry, and glass transition was found for all three: 140 K (nBE), 146 K (iBE) and 150 K (tBE). We were successful in crystallizing nBE and tBE, and determined thermodynamic functions for fusion for the first time. The temperatures of fusion and their enthalpy changes are 199.53 K, 11.8 kJ mol-1 for nBE and 223.09 K, 11.4 kJ mol-1 for tBE. Where possible, we calculated thermodynamic functions. The total entropy in the liquid state at fusion is almost the same, within 1%, between nBE and tBE. However, the values of the liquid heat capacity are about 10% different at the melting point. This indicates that the entropy fluctuation is different while the global average of the entropy remains the same. We measured the density of the liquid and supercooled liquid states for all three samples, and calculated the amplitude, as well as the amplitude plus wavelength of the entropy fluctuation.
Self-Assembled Monolayers of Heme Derivatives on a Gold Surface
Authors: Kobayashi Kazutoshi , Imabayashi Shin'ichiro , Fujita Katsuhiko , Nonaka Kazuhide , Kakiuchi Takashi , Sasabe Hiroyuki , Knoll Wolfgang
Published: September 2002

Thiolated heme derivatives were synthesized and their self-assembly behaviors on gold surfaces together with that of native heme were studied. The kinetics of this adsorption and the thickness of the formed monolayer were investigated by surface plasmon resonance spectroscopy. Native heme shows a different adsorption behavior compared to that of the synthesized derivatives. Though the heme derivatives were found to form monolayers, native heme formed only irregular aggregates on gold surfaces. IR spectroscopy was used to reveal the molecular structure of the adsorbates in the vicinity of the peptide linkage in the heme molecules on the gold surfaces. UV spectroscopy was employed to determine the tilt angle of the porphyrin rings relative to the gold surface normal. Cyclic voltammograms and potential-modulated UV-vis reflectance spectra of heme derivatives were observed in order to estimate the adsorbed amount and the redox behaviors of heme derivatives on gold surfaces.
In-Bond Orbitals: A Comprehensive Graphical Expression of Orbital Interaction
Authors: Ichikawa Hiroshi , Kagawa Hirotaka , Kaneko Chikara
Published: September 2002

The minimal linear-combination-of-atomic-orbitals (LCAO) has a clear chemical meaning, namely, that a molecular orbital consists of atomic orbitals of the member atoms. In organic chemistry, this concept has been applied to graphical expression of orbital interactions. However, the minimal LCAO method is inadequate to illustrate such interatomic interactions. Based on a general idea in quantum chemistry, we have proposed pictorial ``in-bond orbitals'' to compensate for the shortcomings of the minimal LCAO scheme without destroying its simple concept. In-bond orbitals well express the qualitative electronic structures of bonding and antibonding internuclear regions. Furthermore, they are continuously correlated with the AOs of the united atom. In this paper, (1) we discuss the conceptual problems of the minimal LCAO expression in interaction between atoms, (2) we show the importance of the contribution of AOs with higher quantum numbers to the chemical interaction nominally given by AOs with the lowest quantum number, (3) we show that the introduction of a minimal number of in-bond orbitals is a simple method to solve the continuity problem of the correlation diagram and to improve the electronic structure, (4) a selection scheme for in-bond orbitals is proposed, and (5) as an example, the concept of the in-bond orbital is applied to the prediction of the direction of pyramidalization of the olefinic carbon atoms of norbornene.
Characterization of Prochirality and Classification of Meso-Compounds by Means of the Concept of Size-Invariant Subductions
Authors: Fujita Shinsaku
Published: September 2002

The concept of size-invariant subductions has been proposed to design prochiral molecules. Thus, an even-membered homospheric orbit has been proved to be desymmetrized into an enantiospheric orbit, where the sizes of the relevant orbits remain invariant. The concept has been applied to methanes, allenes, adamantanes, and biphenyls. It has proved effective in designing a wide variety of prochiral molecules. These prochiral molecules have been shown to be extrinsic meso compounds. Intrinsic meso compounds have also been discussed as another type of prochiral molecule.
Site-Selective X-Ray Absorption Fine Structure (XAFS) Spectroscopy. (1) Design of Fluorescence Spectrometer and Emission Spectra
Authors: Izumi Yasuo , Oyanagi Hiroyuki , Nagamori Hiroyasu
Published: September 2002

A Rowland-type fluorescence spectrometer was designed to measure site-selective XAFS spectra by utilizing the chemical shift of emission peak for each site. The positions of Johansson-type cylindrically-bent Ge(111) crystal and scintillation counter were controlled independently by five-channel stepping motors, thereby satisfying precise Rowland condition. Thus, measurements of many fluorescence lines over wide ranges of Bragg angle 55.6—83.9° and Rowland radius 127.7—240.9 mm are made feasible. The Cu Kα peak shifted by +1.6 eV on going from Cu to CuCl and by -0.6 eV on going from CuCl to CuCl2. The Cr Kβ1 peak shifted by +0.8 eV on going from Cr to Cr2O3 and by -1.6 eV on going from Cr2O3 to K2CrO4. The FWHM of Cu Kα peaks was as small as 3.0 eV. The major factor to control the energy resolution of this spectrometer was found to be geometrical angle width (slit size). The effects of Rowland radius and X-ray penetration depth into the bent crystal were smaller in the range of slit size in this paper [slit length (horizontal) in front of I0 ion chamber was 0.5—2.0 mm and two slit lengths (vertical) in Rowland circle were 0.5—5.5 mm].
Reinvestigation of Decarboxylation Kinetics from the Hydrogencarbonatocobalt(III) Intermediate
Authors: Kitamura Yoichi , Yano Leona , Fujimori Kazuya , Mizuki Ryuji , Hayashi Masayuki , Shibata Akira
Published: September 2002

Acid-catalysed hydrolysis has been studied by a stopped-flow method at 25 °C, ionic strength of 2.0 (NaClO4) and oxonium ion concentration of 0.02—1.0 M for monodentate carbonato complexes ( [Co(CO3)(NH3)5]+, [Rh(CO3)(NH3)5]+, and [Ir(CO3)(NH3)5]+) and for didentate carbonato complexes ( [Co(CO3)(NH3)4 ]+, [Co(CO3)(en)2]+, α, β-[Co(CO3)(trien)]+, [Co(CO3)(tren) ]+ and [Co(CO3)(nta)]2- (M = mol dm-3, en = ethylenediamine, trien = 1,8-diamino-3,6-diazaoctane, tren = tris(2-aminoethyl)amine, and H3nta = nitrilotriacetic acid) ). The experimental first-order rate constant of decarboxylation from the monodentate hydrogencarbonato intermediate depends on the acidity of the solution, which we ascribe to its amphiprotic character. The deprotonation constant depends critically on an aqua ligand cis to the hydrogencarbonato ligand: 0.004—0.6 M with it, whereas about 10-6 M without it. We interpret that the former strong acidity originates from the stability of the aquacarbonato complex, owing to a strong (21—33 kJ mol-1) intramolecular hydrogen bond. The basicity has been confirmed by the acidity dependent zero-time spectra, the protonation constant being 0.1—0.7 M-1. The hydrolysis rate constant of the monodentate carbonic acid complex has been estimated to be smaller than 0.3 s-1 at 25 °C.
NMR Studies on the Aggregation of Mononuclear and Dinuclear Cobalt(III) Amphiphilic Complexes Having Alkyl Chains
Authors: Iida Masayasu , Sakamoto Akie , Yamashita Taeko , Shundoh Kaori , Ohkawa Shiho , Yamanari Kazuaki
Published: September 2002

The aggregation of novel type cobalt(III) surfactants, such as [Co(en)2{NH2(CH2)2S(1-CnH2n+1)}]3+ (n = 6, 8, and 12) and [(en)2Co{NH2(CH2)2 S(CH2)mS(CH2)2NH2}Co(en)2]6+ (m = 8 and 12), was studied in water using multinuclear NMR spectroscopies, 1H NMR self-diffusions, and 1H NMR chemical shifts. The 59Co linewidths of the surfactants were useful to monitor the premicellar and micellar formation. It was revealed that the tripositive mononuclear surfactants have comparable cmc (critical micelle concentration) values to those for the usual monovalent surfactants having the same alkyl chains. The 35Cl longitudinal relaxation rates for the counterions were useful to monitor the two kinds of ionic interactions, i.e., those with the surfactant monomers and with the micelles. We determined the cmcs for the premicellar formation in the hexyl mononuclear and octyl dinuclear complex systems. The determination of this kind of cmc has become possible by using such highly charged complexes as the cystam complex and by measurements of the 59Co linewidths and of the 35Cl longitudinal relaxation rates. The self-diffusion coefficient for the surfactants revealed that the aggregation behavior is similar in comparison between the hexyl mononuclear and octyl dinuclear complexes or between the octyl mononuclear and dodecyl dinuclear complexes.
Circular Dichroism Spectrophotometric Determination of Metal Ions Using Optically Active Tris(thiolato) Type Rhodium(III) Complexes
Authors: Aizawa Sen-ichi , Sone Yasushi , Khajar Siti , Ohishi Yuuki , Yamada Shinkichi , Nakamura Motoshi
Published: September 2002

Sparingly soluble neutral fac(S)-[Rh(aet)3] was newly optically resolved in order to apply the optically active isomer as a CD-inducing reagent to the circular dichroism (CD) spectrophotometric determination of the transition metal ions. Simple determinations of cobalt(II) and nickel(II) and a simultaneous determination for the binary solution were successful by using an excess of powdery Λ-fac(S)-[Rh(aet)3] with the dissolution equilibrium. A more sensitive determination of the transition metal ions, such as iron(III), iron(II), cobalt(III), cobalt(II), and nickel(II), was possible by using a homogeneous solution of ΔLLL-fac(S)-[Rh(L-cys-N,S)3]3- without the dissolution equilibrium. The latter CD spectrophotometric determination is quite effective for a simultaneous determination of the transition metal ions in binary and ternary solutions of metal ions, such as iron(III)-cobalt(III), cobalt(III)-cobalt(II), and cobalt(II)-nickel(II)-zinc(II).
Rotational Isomerism Involving an Acetylenic Carbon: Synthesis of and Barrier to Rotation around C(sp)-C(sp3) Bonds in Bis(1,4-disubstituted 9-triptycyl)ethynes
Authors: Toyota Shinji , Yamamori Takao , Asakura Mitsuhiro , Oki Michinori
Published: September 2002

The substituent effect on the rotational barriers of acetylenic to tetrahedral C-C bonds was studied for the title compounds carrying Me or OMe substituents at the 1,4-positions in the 9-triptycyl groups. These compounds were prepared by use of the Diels-Alder and the Sonogashira reactions from a 9-ethynylanthracene derivative. The kinetic parameters were determined by the total lineshape analysis of the signals observed by the variable temperature 1H NMR for five compounds. The rotational barriers are in the range of 9—15 kcal mol-1, and are enhanced as the steric size of the substituents is increased (H < OMe < Me). This substituent effect is attributed to the destabilization of the transition state of the rotation process, where the two triptycyl groups are almost eclipsed about the central axis, by the steric interactions between the peri substituents. The acetylenic carbons are significantly deformed from the linear geometry in the X-ray structure of the tetramethyl compound. The substituent effect on the rotamer population is also discussed with the aid of the MM calculation.