bluuebunny/crossref_metadata_2025 huggingface dataset:
Fluorescence Spectra of Eu(II) in Borate and Aluminate Glasses
Authors: Tanaka Katsuhisa , Ohyagi Tomohito , Hirao Kazuyuki , Soga Naohiro
Published: August 2006

The fluorescence and 151Eu Mössbauer spectra have been obtained for alkali borate, alkaline earth borate and rare-earth aluminate glasses containing Eu2+ ions. The Mössbauer spectra indicate that about 70 to 80% of the europium ions are present as Eu2+ ions in the borate glasses. As for the aluminate glasses, almost all of the europium ions are present as Eu2+ ions. The fluorescence spectra due to the 4f65d1 → 4f7 transition of the Eu2+ ion have been observed under excitation with UV radiation. There exists an empirical relationship that the emission energy decreases monotonically with an increase in the theoretical optical basicity of glass, irrespective of the glass systems. This relationship is explained in terms of simple crystal field theory by assuming that the splitting of the 5d levels mainly determines the emission energy of the Eu2+ ions. This empirical relationship also indicates that Eu2+ ions are distributed rather homogeneously in the present borate and aluminate glasses.
Synthesis and Characterization of a Series of Mononuclear Manganese(IV) Complexes with o-(Salicylideneaminomethyl)phenol and Its Substituted Derivatives
Authors: Mikuriya Masahiro , Jie Dai , Kakuta Yoshihisa , Tokii Tadashi
Published: August 2006

A series of manganese(IV) complexes, [Mn (R, R′-L)2]·nS (R or R′ = H, Cl, Br, CH3O; n = 1/2, 1, 3/2, 2; S = H2O, THF (THF = tetrahydrofuran)) where H2(R, R′-L) denotes o-(salicylideneaminomethyl)phenol with the substituent R on the salicylideneamino ring and the R′ on the aminomethylphenol ring, have been prepared and characterized by infrared and electronic spectra, magnetic moments, cyclic voltammetry, and spectroelectrochemical experiment. The molecular structure of [Mn (5-Cl′-L)2]·2THF has been determined by X-ray crystallography. The ligands act as meridional tridentate ONO donors and the complex has an MnO4N2 coordination sphere. The spectral, magnetic, and electrochemical properties are discussed in relation to the molecular structure.
Metal Ion-Selective Adsorbent Prepared by Surface-Imprinting Polymerization
Authors: Tsukagoshi Kazuhiko , Yu Kai Yu , Maeda Mizuo , Takagi Makoto
Published: August 2006

We propose a metal ion-imprinted microsphere as a new metal ion-selective adsorbent. Imprinted microspheres were prepared by seeded emulsion polymerization of divinylbenzene, styrene, butyl acrylate, and methacrylic acid. The imprinted structure was introduced on the carboxylated microsphere by surface-imprinting, in which the carboxyl groups were reorganized through complexation with metal ions on the surface and then fixed by crosslinking polymerization in their specific orientation. The Cu(II), Ni(II), and Co(II)-imprinted microspheres were obtained as submicron particles with average diameters of 0.55—0.60 μm. They were immediately used as a metal ion-selective adsorbent without any further treatment, such as grinding and sieving. The adsorption behaviors of metal ions (Cu(II), Ni(II), and Co(II)) were examined, and the imprinted effects were verified on Cu(II)- and Ni(II)-imprinted microspheres. The imprinted microspheres adsorbed the corresponding guest ion more effectively than did unimprinted ones.
Preparation and Characterization of Dithiocarbamatocobalt(III) Complexes Containing Phosphites, and Molecular Structures of cis-[Co{(CH3)2NCS2}2{P(OCH2)3CC2H5}2]BF4 and [Co(CH2CH2CH2CH2CH2NCS2){P(OCH3)3}4](BF4)2
Authors: Matsui Hayato , Kita Masakazu , Kashiwabara Kazuo , Fujita Junnosuke
Published: August 2006

Eleven new cobalt(III)–phosphite complexes of the [Co(S-S)P4]2+- and [Co(S-S)2P2]+-types were prepared, where S-S denotes bidentate dimethyldithiocarbamate (dtc), diethyldithiocarbamate (etdtc), and piperidyldithiocarbamate (pipdtc) ions, and P is 4-ethyl-2,6,7-trioxa-1-phosphabicyclo[2.2.2]octane (etpb), trimethyl phosphite (pome), and triethyl phosphite (poet). The [Co(S-S)2P2]+-type complexes yielded the cis-isomer in the dark, but isomerized to the trans-isomer in solution by exposure of ultraviolet light. In the photo- and electrochemical reactions, it was inferred that the [Co(S-S)P4]2+-type complexes form a linkage-isomer in which a phosphite ligand is bound to Co(III) through the oxygen atom. Molecular structures of cis-[Co(dtc)2(etpb)2]BF4 (1) and [Co(pipdtc)(pome)4](BF4)2 (2) were determined by the X-ray diffraction method. Crystal data: complex 1, monoclinic, C2/c, a = 23.867(3), b = 17.583(2), c = 15.243(2) Å, β = 103.97(2)°, V = 6208(1) Å3, Z = 8, and R = 0.054 for 2533 reflections; complex 2, monoclinic, P21/c, a = 11.259(2), b = 23.865(4), c = 14.293(2) Å, β = 93.69(1)°, V = 3832.6(10) Å3, Z = 4, and R = 0.072 for 2539 reflections. The average Co–P bond distances of 2.171(1) Å in 1, and of 2.208(3) (trans to S) and 2.242(2) Å (trans to P) in 2 are a little shorter than those of analogous Co(III)–phosphine complexes.
AM1 Calculations for Regioselectivities and Reactivities Observed in Cyanation of 3-Substituted Pyrazine 1-Oxides with Trimethylsilyl Cyanide
Authors: Sakakibara Tohru , Ohwaki Yoshie , Sato Nobuhiro
Published: August 2006

Regioselectivities and reactivities previously reported in the reactions of 3-amino-, 3-cyano-, 3-mehoxy-, and 3-methoxycarbonylpyrazine 1-oxide with trimethylsilyl cyanide were corroborated on the basis of semiempirical molecular orbital calculations (AM method) involving an approach of a cyanide ion to the reactive sites.
High Reactivity of Heterocoerdianthrones (HCDs) in Photoperoxidation and Thermal Stability of Their Endoperoxides. Use of HCD as a Photosensitizer under Sunlight
Authors: Motoyoshiya Jiro , Masunaga Takashi , Harumoto Daisuke , Ishiguro Shigeru , Narita Susumu , Hayashi Sadao
Published: August 2006

The measured reactivity indices (β-values) of heterocoerdianthrones (HCDs) in self-sensitized photoperoxidation indicate a high reactivity toward singlet-oxygen. Such a high reactivity is not only due to an effective singlet-oxygen production due to the highly fluorescent character, but also due to a strained structure, as predicted by a molecular calculation. On the other hand, the large thermal stability of their endoperoxides (POs), revealed by the large activation energy in thermal decomposition, is also explained by considering the strained structure of the parent HCDs. As a prospect of solar synthesis, one of the HCD derivatives was applied to a photosensitizer for singlet-oxygen oxidation.
Peruvianosides A and B, Novel Triterpene Glycosides from the Bulbs of Scilla peruviana
Authors: Mimaki Yoshihiro , Ori Kazutomo , Sashida Yutaka , Nikaido Tamotsu , Song Lian-Gang , Ohmoto Taichi
Published: August 2006

Two new rearranged lanosterol trisaccharides, peruvianosides A (1) and B (2), were isolated from fresh bulbs of Scilla peruviana. Their structures were established mainly by extensive 2D NMR analysis. Peruvianoside A (1) showed an inhibitory activity on cyclic adenosine monophosphate (AMP) phosphodiesterase.
NAD(P)+–NAD(P)H Models. 81. Temperature-Dependent Stereospecificity in the Interconversion between Central and Axial Chiralities
Authors: Okamura Mutsuo , Mikata Yuji , Yamazaki Norimasa , Tsutsumi Akihiro , Ohno Atsuyoshi
Published: August 2006

In the oxidation of (4R)-Me3MQPH or (4R)-Me3PNPH with a series of 1,4-benzoquinone and its derivatives, the R/S ratio with respect to the axial chirality in the product, i.e., 11R-/11S- isomer ratio in Me3MQP+ or 7R-/7S- isomer ratio in Me3PNP+, changes depending on the reaction temperature as well as the reactivity of quinone. It is confirmed that kinetic R-preference stems from the entropy-control, whereas kinetic S-preference comes out of the enthalpy-control. The relative importance of enthalpy and entropy is discussed in terms of the earliness and lateness of the transition state at the initial electron-transfer step.
NAD(P)+–NAD(P)H Models. 82. Effect of Magnesium Ion on the Stereospecificity and Conformations at the Ground and Transition States of the Reaction
Authors: Okamura Mutsuo , Mikata Yuji , Yamazaki Norimasa , Tsutsumi Akihiro , Ohno Atsuyoshi
Published: August 2006

Conformations of 3-[methyl(α-methylbenzyl)carbamoyl]-1,2,4-trimethyl-1,4-dihydroquinoline ((4R)-Me3MQPH) in the presence and absence of magnesium ion have been studied. The major conformation at the ground state of Me3MQPH changes largely when this molecule forms a complex with a magnesium ion. The conformations at the ground and transition states will be discussed in relation to the stereospecificity of the reaction of this compound with quinones.
Formation of a Topochemically Photoreactive Mixed Crystal by Grinding and Its Mechanistic Interpretation
Authors: Kinbara Kazushi , Adegawa Yutaka , Saigo Kazuhiko , Hasegawa Masaki
Published: August 2006

A mixed crystal of ethyl and propyl α-cyano-4-[2-(4-pyridyl)ethenyl]cinnamate was formed in the solid state by simple grinding. The mixed crystal formation was ascertained by the change in the X-ray diffraction pattern upon grinding and by 1H NMR and HPLC analyses of the photoproducts. According to several attempts, it was concluded that a mechanical treatment was necessary for the formation of the mixed crystal phase. The kinetic data concerning the analysis of the topochemical photoproducts revealed that the following growth of the mixed crystal phase was triggered by each of the mixed crystal nuclei and that the growth of the mixed crystal phase was accelerated by either thermal annealing or exposure in humidity. During the early stage of mixed crystal growth, the growth rate was nearly proportional to the surface area of the nuclei of the mixed crystal.
Extraction Kinetics of Ytterbium with Salicylaldehyde n-Octanohydrazone into 1,2-Dichloroethane in the Presence of Both Tributyl Phosphate and Perchlorate
Authors: Odashima Tsugikatsu , Suzuki Teruhiko , Ishii Hajime
Published: August 2006

The kinetics of the solvent extraction of ytterbium(III) from aqueous media with a 1,2-dichloroethane solution of salicylaldehyde n-octanohydrazone (SOH or H2L) in the presence of both tributyl phosphate (TBP) and perchlorate have been studied at 25 ± 0.1 °C and an ionic strength of 0.2 M (1 M = 1 mol dm−3). The rate of extraction was first-order with respect to the concentrations of ytterbium(III) in the aqueous phase and SOH in the organic phase, inversely first-order with respect to the hydrogen-ion concentration and zero- and first-order with respect to the TBP concentration in the organic phase. Two mechanisms operate for this extraction, depending on the TBP concentration in the organic phase. One is a mechanism in which the formation of the first complex, [Yb(HL)]2+, between Yb3+ and HL− in the region of log [TBP]org < −0.95 becomes the rate-determining step, and the other is that in which the formation of the first complex, [Yb(HL)(TBP)]2+, between [Yb(TBP)]3+ and HL− in the region of log [TBP]org > −0.85 is the rate-determining step. The rate constant and activation parameters for the former reaction were calculated, but those for the latter one could not be determined.
Stability and Resonance Energy of Annulated 1-Azaazulenes
Authors: Kurihara Teruo , Kerim Ablikim , Ishikawa Sumio , Nozoe Tetsuo , Abe Noritaka
Published: August 2006

The stability and resonance energy of heterocycle-annulated 1-azaazulenes such as cyclohepta[4,5]pyrrolo[1,2-a]imidazole (5a) and 12-methoxy-5H-cyclohepta[4,5]pyrrolo[2,3-b][1,5]benzodiazepine (7) were elucidated by means of Aihara’s TRE and Gimarc’s TCS rule. These compounds are predicted to be aromatic with positive resonance energies and in conformity with the TCS rule.
The Reaction of 2,3-Dichloro-5,6-dicyano-p-benzoquinone with Benzofurans and Indoles
Authors: Tanemura Kiyoshi , Suzuki Tsuneo , Horaguchi Takaaki
Published: August 2006

The reaction of 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) with 6-methoxy-3-methylbenzofuran gave carbon–oxygen adduct. The reaction in less polar solvents such as benzene and CH2Cl2 proceeds faster than that in more polar solvents such as THF and dioxane. In contrast, the reaction of DDQ with indoles gave carbon–carbon adducts. This reaction proceeds rapidly with increasing solvent polarity.
Synthesis and Structure of [3.3]Orthocyclophane
Authors: Wang Zhen-He , Usui Shuji , Fukazawa Yoshimasa
Published: August 2006

The title compound (1) was synthesized by desulfurization of 2,13-dithia[4.4]orthocyclophane. The molecular structure of 1 which has antiperiplanar arrangement of the two benzene rings was obtained by an X-ray crystallographic analysis. Molecular mechanics calculation using MM3 and our MMRS program has indicated that the anti structure found in crystal is the most stable conformer. Variable temperature 1H NMR measurement has disclosed that the contribution of the conformers other than the anti is negligible.
Syntheses and Electrical Properties of Organosilicon Polymers Containing Thiophene and Anthraquinone Units
Authors: Yi Sang Ho , Ohashi Syunsuke , Sato Hisaya , Nomori Hiroyuki
Published: August 2006

Organosilicon polymers containing thiophene and anthraquinone units in the main chain were synthesized using palladium catalyst. These polymers were soluble and showed a small UV absorption change by the substituents on the silicon atom. Some of the polymers exhibit cation doping (n-doping) by the electrochemical reduction, and this doping process seemed to depend on the kinds of substituents on silicon atom. These polymers showed electrical conductivity of 3 × 10−5 S cm−1 when doped with sodium naphthalenide.
Hexamethyltetralin Preparations Effect of Methyltrioctylammonium Chloride on Solvent/Olefin Interdependency
Authors: Frank Walter C , Miller Donna M
Published: August 2006

The use of quaternary ammonium salts as co-catalysts in the AlCl3 catalyzed cyclialkylation of p-cymene, 2-chloro-2methylpropane, and 3,3-dimethylbutene-1 is reported. The addition of co-catalyst, in solvents which normally give low yields of 1,1,3,4,4,6-hexamethyl-1,2,3,4-tetrahydronaphthalene with 3,3-dimethylbutene-1, improves product yields, comparable with the best published 3,3-dimethylbutene-1 methodology. Addition of co-catalyst permits the use of more environmentally acceptable solvent systems than those in existing syntheses of the desired tetralin. The yield improvement is rationalized on the basis of improved reaction homogeneity, facile cleavage of Al2Cl6 by Cl− ion, and increased effective solvent polarity, promoted by addition of the quaternary ammonium salt co-catalysts.

Addition of quat co-catalysts to 3,3-dimethylbutene-1 based cyclialkylation systems did not increase rate, catalyst homogeneity or yield relative to a control (dichloromethane solvent). This suggests that the chlorinated hydrocarbon solvents normally used in this technology provide functions similar to that of quats in 2,3-dimethylbutene-1 based technology. These functions include the abilities to enhance AlCl3 solubility, increase the polarity of the reaction medium, and provide facile scission of Al2Cl6 to a more active catalytic species.

In reactions where 2,3-dimethylbutene-1 is substituted for 3,3-dimethylbutene-1, addition of co-catalyst improves reaction rate, catalyst homogeneity, and yield reproducibility in non-polar solvents when compared to the best published, 2,3-dimethylbutene-1 methodology.
Boron Compound as a Trapping Reagent of α-Hydroxy o-Quinodimethanes in the Diels–Alder Reaction
Authors: Shimada Satoru , Osoda Kazuhiko , Narasaka Koichi
Published: August 2006

The Diels–Alder reaction of methyl 4-hydroxy-2-butenoate and α-hydroxy o-quinodimethanes, generated from 1,2-dihydrobenzocyclobuten-1-ol derivatives by thermolysis, proceeds by the use of phenylboronic acid as a template. Boron reagents trap an α-hydroxy o-quinodimethane (5-methylene-6-(1-hydroxyalkylidene)-1,3-cyclohexadiene) generated photochemically from o-tolualdehyde and the Diels–Alder reaction with methyl 4-hydroxy-2-butenoate occurs to give the cycloadducts.
Dependence of the Lewis Acid-Induced Reaction of β-Stannyl Ketones upon Substitution Pattern: Cyclopropanation versus 1,2-Alkyl Migration
Authors: Fujiwara Jun , Sato Tadashi
Published: August 2006

3-Stannylcyclohexanones fully substituted at 2 and 3 positions underwent a 1,2-alkyl migration, along with the cyclopropanation. The balance of the reactions depended upon the steric environment and migratory aptitude of the alkyl groups.
Studies on Identification of Soot. V. Changes in Alkylbenzenes and Alkanes in Diffusion Flame
Authors: Takatsu Masahisa , Yamamoto Tadahiro
Published: August 2006

Changes in the diffusion flames of benzene, toluene, p-xylene, ethylbenzene, styrene, cumene, octane, and decane fuels were comparatively examined. Original fuels and dealkylation products were observed in the flames of the alkylbenzenes. Styrene was also found as an elimination product in the flames of ethylbenzene and cumene. The profiles of these products should depend on the structures of the side chains of the original alkylbenzenes. On the other hand, the two alkanes were easy to cleave and changed into smaller alkenes in the flame faster than the six other alkylbenzenes.
Synthesis and Properties of High Molecular Weight Polypeptides Containing Proline
Authors: Iizuka Yasuko , Uchida Chieko , Wakamatsu Kaori , Oya Masanao
Published: August 2006

High-purity N-carboxy-l-proline anhydride (N-carboxy-2-pyrrolidinecarboxylic acid anhydride) was synthesized. We used triethylamine instead of expensive Ag2O to remove HCl during the synthesis. Copolypeptides with a random sequence of l-proline (Pro) with glycine, l-alanine (Ala), l-α-aminobuthyric acid (Abu), l-Norvaline (Nva) or l-leucine (Leu) were synthesized by copolymerization of the corresponding N-carboxy-α-amino acid anhydrides in solution. Copolypeptides of Pro with Ala or Abu were partially soluble in water. However, the copolypeptides of proline with Nva or Leu with longer side chains were insoluble in water. The conformation of water-soluble copolymer at various pH was analyzed by circular dichroism (CD). The structures of the polypeptides in aqueous solution were almost independent of the pH, and were in a collagen-like conformation.
Unusual Effects of the Reaction Temperature on the Catalytic Activity of Rh/Active-Carbon for Ethylene Hydroformylation
Authors: Takahashi Nobuo , Sato Yoshinori , Uchiumi Takahiro , Ogawa Kazuo
Published: August 2006

The apparent activation energies for propionaldehyde and ethane formation from C2H4, CO, and H2 on a Rh/active-carbon catalyst, once used for a reaction at 453 K, were found to be 40 and 76 kJ mol−1, respectively. These values were much lower than those on a fresh Rh/active-carbon catalyst (120 and 125 kJ mol−1). Changes in the apparent activation energies were also induced by exposure of a fresh catalyst to CO at temperatures > 433 K. Such catalytic behaviors, however, were not observed on a Rh/silica-gel catalyst. On the fresh Rh/active-carbon catalyst, the amount of adsorbed CO was found to be much more than that of adsorbed H2. The temperature-programmed desorption spectrum (TPD) of CO on the catalyst exposed to CO at 353 K after an H2 treatment at 573 K showed a single desorption peak at ca. 470 K; the value for the CO/Rh molar ratio was found to be 2.6. The amount of CO desorbed from the catalyst exposed to CO at 473 K, however, was found to be much less than that on the catalyst exposed to CO at 353 K. Namely, unusual effects of the reaction temperature on the catalytic activities, which were observed on the fresh Rh/active-carbon catalyst, were very closely related to changes in the amount of CO desorbed from the catalyst during TPD runs.
Structural Characterization and Catalytic Behavior of Al2O3-Supported Cerium Oxides
Authors: Haneda Masaaki , Mizushima Takanori , Kakuta Noriyoshi , Ueno Akifumi , Sato Yasunori , Matsuura Shinji , Kasahara Koichi , Sato Masayasu
Published: August 2006

Three kinds of supported cerium oxide catalysts were prepared by an impregnation and a sol–gel technique using aluminium tri-isopropoxide (AIP) and cerium(III) nitrate dissolved in ethylene glycol. One is cerium dioxide supported on alumina, and others are finely-divided nonstoichiometric cerium oxide and cerium aluminate crystallites dispersed on alumina, respectively. In order to investigate the relationship between the structure of cerium oxides and their catalytic behavior, these cerium oxides were subjected to “OSC” (oxygen storage capacity) measurements as well as kinetic studies for methane oxidation. The highest “OSC” was achieved on the finely-divided nonstoichiometric cerium oxides. Kinetics studies for methane oxidation resulted in the first order with respect to methane for all the catalysts, and nearly zero order with respect to oxygen on the cerium dioxide and cerium aluminate. While on the finely-divided nonstoichiometric cerium oxides a half order with respect to oxygen was obtained. On the basis of these results the structure and the catalytic behavior of cerium oxides was discussed in terms of the “OSC” associated with the oxygen vacancies existed in the finely-divided nonstoichiometric cerium oxides. A brief discussion was also made on Pd catalysts supported on these cerium oxides for methane oxidation.
Electrochemical Properties of Coenzyme Pyrroloquinolinequinone Using a Di-(4-pyridyl) Disulfide Modified Gold Electrode under Acidic Conditions
Authors: Nakamura Nobuhumi , Kohzuma Takamitsu , Suzuki Shinnichiro
Published: August 2006

The reversible electron transfer behavior of pyrroloquinolinequinone (PQQ) using a di-(4-pyridyl) disulfide (4-pyds) modified gold electrode was observed by cyclic voltammetry and the optically transparent thin-layer electrode (OTTLE) method under acidic conditions.
Facile Oxidative Coupling of Benzene by the Palladium(II) Acetate–Dialkyl Sulfide System
Authors: Fuchita Yoshio , Taga Masashi , Kawakami Mina , Kawachi Fumiko
Published: August 2006

By the palladium(II) acetate–dialkyl sulfide system, oxidative coupling of benzene has been achieved at 70 °C, where palladium(II) acetate alone is inactive for the reaction. Effects of alkyl group on the sulfides, molar ratios of sulfide to palladium(II) acetate, and atmosphere of oxygen have been investigated.
The Structure of Physalin P, a Neophysalin from Physalis Alkekengi
Authors: Kawai Masao , Matsumoto Akihide , Makino Bunsho , Mori Hideyuki , Ogura Toichi , Butsugan Yasuo , Ogawa Kiyoshi , Hayashi Mitsuo
Published: August 2006

The structure of physalin P, a constituent of Physalis alkekengi var. francheti, was determined to be 5α-hydroxy-6,7-didehydro-5,6-dihydroneophysalin B by spectroscopic study and chemical correlation with a known compound.
Beckmann Reaction of Oximes of 3a-Aryl-5,6a-diphenyl-3a,6a-dihydro-2H-furo[3,2-b]pyrrole-2,6(3H)-dione and Its Derivatives
Authors: Mataka Shuntaro , Suzuki Hiroshi , Sawada Tsuyoshi , Tashiro Masashi
Published: August 2006

In the reaction with pyrrolidine, the (Z)-6-oxime (2) of 3a-aryl-5,6a-diphenyl-3a,6a-dihydro-2H-furo[3,2-b]pyrrole-2,6(3H)-dione (1) gave the (Z)-oxime (3) in which the lactone ring was opened. (Z)-Oxime 3 isomerized on silica gel to give (E)-oxime 4. Treatment of 2 with tosyl chloride in aqueous ethanolic sodium hydroxide afforded 5-aryl-2-cyano-2-phenyl-1H-pyrrol-3(2H)-ones (7) in yields of 41—90%, while both 3a and 4a gave the pyrroline-ring-opened product 8 in moderate yields.
Intramolecular Through-Space Interaction in 2-(p-Methoxyphenyl)-2-butenyl 9-Phenanthrenecarboxylate as Evidenced by Their Isomerization Behavior
Authors: Itoh Hiroki , Senda Yasuhisa , Sakuragi Hirochika , Tokumaru Katsumi
Published: August 2006

Intramolecular quenching of the excited singlet state of a phenanthrene moiety was more efficient in (E)-2-(p-methoxyphenyl)-2-butenyl 9-phenanthrenecarboxylate (E-ABP) than in its Z isomer (Z-ABP) in benzene. The quenching is proposed to proceed in a through-space fashion on the basis of efficiencies of isomerization and photophysical processes as well as molecular orbital calculations.
Characteristic Response of Electrochemical Nonlinearity to Taste Compounds with a Gold Electrode Modified with 4-Aminobenzenethiol
Authors: Mohri Nobuyuki , Katsuya Yoshio , Nakata Satoshi , Yoshikawa Ken-ichi
Published: August 2006

The nonlinear electrochemical responses for various taste compounds were measured using a gold electrode modified by 4-aminobenzenethiol. The results were analyzed quantitatively based on a data-processing method proposed by the authors. The nonlinearity of the response was found to be enhanced by the modification, showing a marked dependence on the categories of taste compounds as well as on their concentrations. Our new concept concerning chemical sensing has been found to be promising as a powerful analytical tool when a suitable modification of the electrode surface is performed.
The Mechanism of Fries Rearrangement and Acylation Reaction in Polyphosphoric Acid
Authors: Sharghi Hashem , Eshghi Hossien
Published: August 2006

Acylation reaction of m-cresol with 2-chlorobenzoic acid in PPA occurred through a prior esterification, followed by a Fries rearrangement of ester (3) to give benzophenones 4—7.

Ester 3 undergoes the Fries rearrangement in PPA, giving benzophenones 4—7 in about the same yield as can be obtained by direct acylation reaction of m-cresol with 2-chlorobenzoic acid. The benzophenone 5 is not stable in PPA and decomposed to benzophenone (4). The formation of benzophenones 4—7, from Fries rearrangement of the ester 3 was interpreted by an intermolecular mechanism.
Behavior of Surfactants in a Highly Loaded Coal–Water Slurry. II. Effects of Coal Properties on the Behavior of a Surfactant
Authors: Ogura Tsugitoshi , Tanoura Masazumi , Hiraki Akio
Published: August 2006

The roles and behaviors of two kinds of anionic surfactants were investigated in order to clarify their influence on the properties of a highly loaded coal water slurry (CWM) prepared from six kinds of coals. It was confirmed that the adsorbed surfactants on coal particles and their presence in water were both required for preparing practical CWMs of every type of coal. The ion concentrations of alkaline earth metals and protons derived from coal increased the adsorption of surfactants; the amounts of the adsorbed surfactants varied from coal to coal. A surfactant of molecular weight around 5000 was found to be preferentially adsorbed, and thus the most effective for controlling the properties of the CWM.
The Thin Film of a Fluorine-Containing Polymer with Cyclodextrin Prepared by the Langmuir–Blodgett Technique and Its Application to Photochromic Thin Films
Authors: Tamura Masanori , Sekiya Akira
Published: August 2006

A polymer synthesized from polyallylamine by perfluoroacylation was spread on an aqueous solution of a cyclodextrin derivative possessing a carboxyl group, and a thin film of the fluorine-containing polymer to which a cyclodextrin moiety was introduced was prepared by the Langmuir–Blodgett technique. Azobenzenes were incorporated in the polymer thin film as the inclusion complex by using the aqueous solution containing both the cyclodextrin derivative and azobenzenes as a subphase, and novel photochromic thin films of fluorine-containing polymers were obtained. Characterization of these films indicated that they showed excellent low surface energy due to the perfluoroalkyl group in the polymer. The influences of the incorporated cyclodextrin moiety on the molecular arrangement, the surface energy, and the film thickness are discussed.
High Temperature Corrosion of Fe Coated with a (Li0.62K0.38)2CO3 Melt
Authors: Kim Baek-un , Yoshitake Hideaki , Yokokawa Harumi , Kamiya Nobuyuki , Ota Ken-ichiro
Published: August 2006

The corrosion of Fe in the presence of (Li0.62K0.38)2CO3 has been studied under an O2/CO2 atmosphere at 823—1073 K by TGA. The corrosion of Fe coated with a (Li0.62K0.38)2CO3 melt obeyed the parabolic rate law, and LiFeO2 and LiFe5O8 were formed. Under these conditions severe corrosion did not occur because of the low solubility of iron oxide in the melt. When Fe was immersed in (Li0.62K0.38)2CO3, the reaction obeyed the linear rate law and Li5FeO4, LiFeO2, and LiFe5O8 were formed. This was in accordance with the thermochemical phase study. Li5FeO4 was mostly formed during the intitial period of the corrosion reaction and caused a weight decrease of the reaction cell (specimen+melt) by the liberation of CO2. LiFe5O8 was formed in the later period of the reaction.
Reaction of 2,3-Dichloro-5,6-dicyano-p-benzoquinone with 1,10-Phenanthroline and the Crystal Structure of Its Reaction Product
Authors: Tanaka Masashi , Oyama Munekata , Mizoguchi Jun-ichi , Kashino Setsuo
Published: August 2006

2,3-Dichloro-5,6-dicyano-p-benzoquinone reacted with 1,10-phenanthroline to give 1,10-phenanthrolinium 4,5-dichloro-2-cyano-3,6-dioxo-1,4-cyclohexadien-1-olate. The reaction in acetonitrile solution was observed by the stopped flow technique and the UV-visible absorption spectra measurement. The crystal structure of its reaction product was determined by the X-ray diffraction study. The crystal was monoclinic, space group P21 with a = 12.323(4), b = 4.897(2), c = 13.677(3) Å, β = 96.51(3)°, V = 820.0(8) Å3, Z = 2, and final R = 0.041 for 1280 reflections larger than 3σ(I°). The planar cations and anions stack along the b axis, respectively, to form the segregated columns.
Synthesis, Molecular Structure, and Physical Properties of an Oxomolybdenum(IV) Complex with p-Chlorobenzenethiolate, [MoIVO(p-ClC6H4S)4]2−, as a Model of Active Sites of Reduced Molybdo-Oxidases
Authors: Kondo Mitsuru , Ueyama Norikazu , Fukuyama Keiichi , Nakamura Akira
Published: August 2006

A monomeric oxomolybdenum(IV) complex with p-chlorobenzenethiolate, (NEt4)2[MoIVO(p-ClC6H4S)4] (1a), was synthesized as a relevant model of active sites of reduced molybdo-oxidases by reduction of (NEt4)[MoVO(p-ClC6H4S)4] (2) with NEt4BH4. This complex was characterized by absorption, Raman, and 1H NMR spectra and cyclic voltammograms, and compared with 2. The complex (PPh4)2[MoIVO(p-ClC6H4S)4] (1b), which was prepared by the cation exchange reaction of 1a, crystallizes in the triclinic, space group with a = 21.131 (18), b = 13.690(3), c = 13.490(5) Å, α = 100.96(3)°, β = 117.62(3)°, γ = 78.77(5)°, and Z = 2. The average distances of Mo–S and Mo–O bonds of this complex are 2.415 and 1.690(9) Å respectively. The O–Mo–S–C torsion angles (θ) in 1b range from 74° to 91°. EHMO calculation on [MoIVO(SH)4]2− showed that this conformation is thermally stable.
Hydrolytic Metalloenzyme Models. Catalysis in the Hydrolysis of p-Nitrophenyl 2-Pyridinecarboxylate by Copper and Zinc Ion Complexes of Anionic Surfactants Having a Functional Imidazole and Hydroxyl Moieties
Authors: Tagaki Waichiro , Ogino Kenji , Fujita Tsunehisa , Yoshida Toshiharu , Nishi Kazuyoshi , Inaba Yoichi
Published: August 2006

Two anionic surfactant-ligands, sodium 2-[1-dodecyl-2,5-bis(dihydroxymethyl)-4-imidazolyl]methylthioethanesulfonate (1) and sodium 1-hexadecyl-2-(2-hydroxymethyl-1-imidazolyl)ethyl sulfate (2), each having a functional imidazole and a hydroxyl moiety, have been examined regarding their catalytic activities in the hydrolysis of p-nitrophenyl 2-pyridinecarboxylate (PNPP) in the presence of Zn2+ or Cu2+ and under co-micellar conditions with surfactants. All of the ligands underwent a remarkable activation of the 2-hydroxymethyl group for transacylation from PNPP when complexed with Cu2+. Some interesting differences were observed between the two ligands, 1 and 2, such as in the modes of complexation and the effects of co-micellar surfactants.
Model Studies of Catechol Dioxygenases. Important Role of Monodentate Catecholate-Iron(III) Intermediate
Authors: Fujii Satoshi , Ohya-Nishiguchi Hiroaki , Hirota Noboru , Nishinaga Akira
Published: August 2006

The catechol dioxygenase model reactions of three model systems have been investigated by EPR, optical, and electrochemical studies. In each model system, some kinds of intermediates could be detected by EPR and optical spectroscopies. The intermediate structures and the reaction times suggest that the monodentate catecholate complexes play an important role in the catalytic cycle. Based on the EPR spectra obtained aerobically and anaerobically, iron(III)-monodentate dianionic catecholate is the O2 reactive species for Fe(nta) (nta = nitrilotriacetato) and Fe(sal-l-aa)Cl (sal-l-aa = N-salicylidene l-amino acidato) systems and iron(II)-semiquinonate for Fe(salen)Cl (salen = N,N′-ethylenebis(salicylideneaminato) system. Electrochemical data suggest that this electron transfer in Fe(salen)Cl system is caused by the ligand distortion. The catecholate-(sal-l-val)iron(III) complex reacted with dioxygen to yield the ring cleavage products (ca. 80%). On the basis of the observations, the novel reaction mechanism of the Fe(sal-l-aa)Cl system having mainly monodentate catecholate intermediate, is proposed. Finally, the correlation between the coordination environments of non- heme iron(III) complexes and EPR parameters is discussed.
Determination of Monovalent Inorganic Anions in Human Saliva by Ion Chromatography Using Microcolumn Coated with Micellar Zwitterionic Bile Acid Derivative.
Authors: Hu Wenzhi , Haraguchi Hiroki
Published: August 2006

Anions such as nitrite, nitrate, iodide, and thiocyanate ions contained in human saliva have been determined by ion chromatography using a microcolumn coated with micellar bile acid derivative, 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate, where only a phosphate buffer solution was used as the mobile phase. The detection limits obtained by the present system were 1.1 μM for nitrite and nitrate, 2.3 μM for thiocyanate, and 0.48 μM for iodide when the direct UV absorption detection of the anions was performed at 230 nm. The present system was applied to the determination of inorganic anions in human saliva, especially in relation with smoking habit, age and sex. Thiocyanate ion was detected at the significantly higher level in saliva for the smokers, compared to the non-smokers. Furthermore, the thiocyanate levels in saliva depended on the age and sex, while the concentrations of nitrite, nitrate, and iodide ions were rather independent of these parameters.
Synthesis and the X-Ray Crystal Structure of [(μ-H)Os5Cu(CO)18(PPh3)]
Authors: Ang H G , Kwik W L , Ng K H
Published: August 2006

The hexanuclear bimetallic cluster [(μ-H)Os5Cu(CO)18(PPh3)] (1), was prepared from the reaction of [(μ-H)2Os3(CO)10] with CF3COOCuPPh3. 1 was shown by X-ray analysis to consist of a pentaosmium framework with a copper atom bridging four of the osmium atoms to form a puckered “ladder-like” arrangement based on four triangular units.
Dehydroamination Reaction of 9-Amino-9,10-dihydrophenanthrene and Related Compounds by Thermolysis
Authors: Yasuda Masahide , Harada Takamitsu , Ansho Yasuhiro , Shima Kensuke
Published: August 2006

Dehydroamination of 9-alkylamino-9,10-dihydrophenanthrene occurred at 190—250 °C under non-basic conditions to give phenanthrene exclusively. The thermal reaction of cis-9-t-butylamino-10-methoxy-9,10-dihydrophenanthrene gave both 9-methoxyphenanthrene and 9-t-butylaminophenanthrene, while 9-aminophenanthrene was obtained from the thermal reaction of 9-amino-10-methoxy-9,10-dihydrophenanthrene. The thermal reaction of 9-amino-9,10-dihydroanthracene gave both anthracene and 9-aminoanthracene. Analysis of activation energies and frequency factors showed that the dehydroamination proceeds via an intramolecular proton transfer from C-10 to the amino group and subsequent C–N bond cleavage.
Ca2+-Induced Aggregation of Oligopeptides Having a Carboxyl Group in Phospholipid Bilayer Membrane
Authors: Otoda Kazuya , Kimura Shunsaku , Imanishi Yukio
Published: August 2006

Ca2+-induced aggregation of peptides having an Asp residue in phospholipid bilayer membrane was studied on the basis of excimer formation of pyrenyl group in the peptide. A part of the peptides incorporated into the membrane formed aggregates. The degree of peptide aggregation in the membrane was maximum at the lipid/peptide molar ratio of 40—80, and decreased with increasing the amount of the lipid and dissociation of the carboxyl group. Cross-linking of the peptide by Ca2+ was observed only when the peptide concentration in the membrane was high and the carboxyl group was dissociated. The membrane fluidity at the surface and in the hydrophobic core was not influenced so much by the peptide aggregation, indicating that the peptide/Ca2+ complex is not very rigid.
Syntheses of 9-Phenylsufonylimino-1,4-dioxa-8,10-diazacyclotridecanes and 9,22-Bis(phenylsulfonylimino)-1,4,14,17-tetraoxa-8,10,21,23-tetraazacyclohexacosanes: Macrocyclization via Dimethyl N-Phenylsulfonylcarbonimidodithioates
Authors: Fukada Naoaki , Takano Minoru , Nakai Kazutaka , Kuboike Satoshi , Takeda Yasuyuki
Published: August 2006

The reaction of dimethyl N-phenylsulfonylcarbonimidodithioates (1) with diamines gave three different types of products due to changes in the molar ratio of the starting materials. From aliphatic diamines heterocyclic 1 : 1 and acyclic 2 : 1 reaction products were obtained. In order to prepare macrocycles, the reaction of 1 with 1,10-diamino-4,7-dioxadecane (10) was carried out. 1,1′-(4,7-Dioxadecamethylene)bis(2-methyl-3-phenylsulfonylisothiourea)s (11) and 9-phenylsulfonylimino-1,4-dioxa-8,10-diazacyclotridecanes were obtained by 2 : 1- and 1 : 2-mixed reactions of 1 with 10, respectively. The 2 : 2 reaction products, 9,22-bis(phenylsulfonylimino)-1,4,14,17-tetraoxa-8,10,21,23-tetraazacyclohexacosanes, were prepared from 1 and a greater excess of diamine 10 (1 : 4) or from 11 and diamine 10.
Photoisomerization of Bilirubins and the Role of Intramolecular Hydrogen Bonds
Authors: Kanna Yoko , Arai Tatsuo , Tokumaru Katsumi
Published: August 2006

The quantum yields and the photostationary state isomer ratios in the photoisomerization of bilirubin are strongly governed by the properties of the reaction media. Among the reaction media examined, the quantum yields for ZZ→ZE isomerization (φZZ–ZE) and for cyclization (φLR) were the highest in buffered aqueous solution (potassium phosphate buffer, pH 7.4) containing human serum albumin (HSA) in a 1 : 1 molar ratio to ZZ-BR, 0.11 and 2 × 10−3, respectively, on 436 nm irradiation. The effects of the reaction media surrounding bilirubin are discussed.
X-Ray Structural Investigation of the Chiral Recognition of Brucine in Salt Formation with an N-Protected Amino Acid, N-Phthaloyl-threo-β-hydroxy-d- and l-leucine
Authors: Kuwata Shigeru , Tanaka Jumpei , Onda Norihiro , Yamada Takashi , Miyazawa Toshifumi , Sugiura Makiko , In Yasuko , Doi Mitsunobu , Inoue Masatoshi , Ishida Toshimasa
Published: August 2006

In order to determine how brucine recognizes the chirality of an N-protected amino acid in complex formation, three kinds of brucine complex crystals of N-phthaloyl-threo-β-hydroxyleucines, i.e., two (yellow and transparent) crystals for the l-isomer and one (transparent) crystal for the d-isomer, were prepared, and their structures were determined by X-ray crystallography. In addition to the interaction mode specific for each complex crystal, the carboxyl and β-hydroxyl groups of the amino acids were commonly linked with the methoxyindole and piperidine ring moieties of brucine through hydrogen bonds and electrostatic and van der Waals interactions. In addition to the direct interactions between the molecules, the molecular arrangement of brucine in the crystal structure played an important role in the d/l-recognition of the amino acids. The molecular packing of the brucine molecules translated by a crystallographic 2-fold screw symmetry operation provided a shape for the cavity that was most suitable for binding with the d-isomer. In contrast, two crystallographically independent brucine molecules participated in recognizing the l-isomer, where the arrangement of these molecules in the crystal structure formed a receptor surface suitable for binding with the l-isomer. In this paper, an explanation of how brucine recognizes the d/l-isomer in the crystalline state is presented.
A New and Efficient Esterification Reaction via Mixed Anhydrides by the Promotion of a Catalytic Amount of Lewis Acid
Authors: Miyashita Mitsutomo , Shiina Isamu , Miyoshi So , Mukaiyama Teruaki
Published: August 2006

In the presence of a catalytic amount of Lewis acid, various carboxylic esters or S-phenyl carbothioates are prepared in excellent yields by the respective reactions of equimolar amounts of silyl carboxylates and alkyl silyl ethers or phenyl silyl sulfides with 4-trifluoromethylbenzoic anhydride.
Synthesis of Homoallylamines by the Addition of Allylic Indium Reagents to Azomethines and Nitriles
Authors: Jin Shun-Ji , Araki Shuki , Butsugan Yasuo
Published: August 2006

Triallyldiindium trihalides and allylindate(1-)s reacted with N-benzylideneamines regioselectively at the C-3 carbon on the allyl group to give high yields of homoallylic secondary amines. Primary amines were obtained by the action of an excess of allylic indates on aromatic nitriles.
Thermal Decomposition of the Iron(III) Hydroxide and Magnetite Composites of Poly(vinyl alcohol). Preparation of Magnetite and Metallic Iron Particles
Authors: Yokoi Hiroshi , Kantoh Teruyuki
Published: August 2006

Upon the precipitation of iron(III) hydroxide (Fe(OH)3) and magnetite in the presence of poly(vinyl alcohol) (PVA) at R < 3, PVA is bound to the precipitates in very high yields, where R = [PVA polymer residue]/[Fe ion]. The thermal decomposition of the Fe(OH)3–PVA composite at R = 1.0 by heating at ca. 700 °C in nitrogen for 10 min or more affords almost pure iron metal particles of ca. 200 Å in diameter; almost no residues originating from the PVA remain. Before formation of the metallic iron, magnetite particles are produced as its precursor in the 250—650 °C temperature range, where the particle size increases with increasing temperature from ca. 80 up to ca. 350 Å in diameter, although these iron and magnetite products are not uniform, but are agglomerate or sintered particles. In these processes, the initially bound PVA effectively functions as a reducing agent during its own decomposition.
Vapor-Phase Oxidation of Ethyl Lactate to Pyruvate over Various Oxide Catalysts
Authors: Sugiyama Shigeru , Shigemoto Naoya , Masaoka Naoki , Suetoh Souichi , Kawami Hideaki , Miyaura Keiko , Hayashi Hiromu
Published: August 2006

Oxidation of ethyl lactate to pyruvate was carried out in vapor-phase over various oxides. MoO3 showed a higher selectivity than that of the other single oxide examined. Binary oxides containing molybdenum such as Fe2O3–MoO3 and TeO2–MoO3 showed high selectivities to pyruvate over 90% at 300 °C with high lactate conversion over 75%. The maximum activity on SnO2–MoO3 was observed at a low temperature of 250 °C.
Effect of Water on the Acidic Properties of Layered HLaNb2O7
Authors: Matsuda Tsuneo , Fujita Tetsuya , Miyamae Naosuke , Takeuchi Mitsuru , Kanda Kazuko
Published: August 2006

The irreversible water in the interlayer of HLaNb2O7 (HLa), which was removed in the temperature range of 350—400 °C, greatly affected the formation of acidic properties of the HLa. The reversible water removed at lower temperature than 350 °C did not greatly affect the acidic character of the HLa. The relations between the isoelectric points and heat-treatment temperature of the HLa were examined in connection with the acidity.
Intercalation of Various Alcohols in HLaNb2O7
Authors: Matsuda Tsuneo , Miyamae Naosuke , Takeuchi Mitsuru
Published: August 2006

The intercalation of various alcohols into the interlayer of HLaNb2O7 was investigated. Normal alcohols having carbon numbers from one to five were inserted into the interlayer in the presence of water. The intercalation of alcohols was ascribed to the hydrophilic property of n-alcohols.
Production of Thiosulfate Anion from the Reaction of Bis(dialkyldithiocarbamato)nickel(II) Complexes with Ethylenediamine
Authors: Ramalingam Kuppukkannu , Aravamudan Gopalasamy , Venkatachalam Venkattan
Published: August 2006

Planar divalent nickel dithiocarbamates Ni(dtc)2 (dtc− = dithiocarbamato anions) show interesting reactivity patterns in their reactions with Lewis bases. These complexes form mixed ligand complexes with PR3 easily. But, simple hard nitrogen bases do not displace all the nickel dithiocarbamates. A chelating base like en displaces the dithiocarbamate anion completely from the complexes and formed pink colored solution in an aqueous medium. The chromophore was identified to be [Ni(en)3]2+ and the counter anion was dtc−. On ageing, pink crystals separated out from the solution. Chemical analysis of the crystals showed a 1 : 2 ratio of Ni to S and the absence of dtc− ion. The possibility of S2O32− being the counter anion was tested. Even though infrared spectrum could not confirm the S2O32− anion, the final confirmation came form the X-ray analysis of the authentic crystals. This is a rare occasion of metal ion catalyzed oxidation of S2− to S2O32− ions.
Preparation of Cobalt(III) and Nickel(II) Complexes Having an Alkyl Long Chain and Their Surface Tension Reducing Abilities
Authors: Yashiro Morio , Matsumoto Katsuya , Seki Nobuo , Yoshikawa Sadao
Published: August 2006

Cobalt(III) and nickel(II) complexes having an alkyl long chain were newly prepared. The critical micelle concentration and surface tension-reducing ability largely depend on the length of the alkyl-chain, the position of its substitution on the ligand, and counter ions. Solvatochromism was observed for a nickel(II)–tetraamine complex having a dodecyl chain.
Circular Dichroism Spectra of Synthetic Steroidogenesis-Activator Polypeptide and Its Fragments
Authors: Watanabe Eiji , Nozaki Sukekatsu , Akiyama Minoru , Muramatsu Ichiro
Published: August 2006

Circular dichroism spectroscopic analysis of synthetic steroidogenesis-activator polypeptide (SAP) and its fragments in 2,2,2-trifluoroethanol-containing media suggests that SAP holds two folding sites in the N- and C-terminal regions. The N-terminal folding shows some vulnerability toward acidic conditions, while the C-terminal folding prefers to acidic circumstances.
A One-Pot Peptide Synthesis via

Se

-phenyl Carboselenoate in Mixed Aqueous/Organic Solvent System
Authors: Ghosh Sunil Kumar , Singh Usha , Chadha Mohindra S , Mamdapur Vasant R
Published: August 2006

A one pot synthesis of peptides with free C-terminal residues has been accomplished via the active Se-phenyl carboselenoate using diphenyl diselenide, tributylphosphine, and N-methylmorpholine N-oxide in an acetonitrile– water mixed solvent system. Free amino acids and peptides have been used as the amine component without pH adjustment.
Photochemical Reactions of Diphosphenes Carrying 2,4,6-Tris(trifluoromethyl)phenyl Group
Authors: Yoshifuji Masaaki , Abe Masatoshi , Toyota Kozo , Goto Kei , Inamoto Naoki
Published: August 2006

Photoreactions of 1,2-bis[2,4,6-tris(trifluoromethyl)phenyl]diphosphene and 1-(2,4,6-tri-t-butylphenyl)-2-[2,4,6-tris(trifluoromethyl)phenyl]diphosphene were studied. The latter diphosphene gave formally an intramolecular cyclization product by photoirradiation, whereas the former diphosphene showed no change on irradiation.
Halogenation Using N-Halogenocompounds. I. Effect of Amines on ortho-Bromination of Phenols with NBS
Authors: Fujisaki Shizuo , Eguchi Hisao , Omura Atsushi , Okamoto Atsushi , Nishida Akiko
Published: August 2006

Primary and secondary amines, especially diisopropylamine and dibutylamine, catalyzed ortho-dibromination of phenol and ortho-monobromination of 2-substituted phenols with NBS in dichloromethane to give selectively 2,6-dibromophenol and 2-bromo-6-substituted phenols, respectively. The effective intermediates are inferred to be N-bromoamines. The scope and limitations of the bromination are also presented.