bluuebunny/crossref_metadata_2025 huggingface dataset:
Syntheses, and Crystal and Molecular Structures of Tetraethylammonium [Hexakis(isothiocyanato)lanthanoidates(III)] Including Aromatic Hydrocarbon or Halohydrocarbon: [(C2H5)4N]3[M(NCS)6]·G (M=Er, or Yb; G=Benzene, Fluorobenzene, Toluene, or Chlorobenzene)
Authors: Arai Hisanori , Suzuki Yasuo , Matsumura Naomi , Takeuchi Toshio , Ouchi Akira
Published: July 2006

The title new complexes were synthesized and their crystal and molecular structures were determined by the single-crystal X-ray diffraction method. The crystal form of [(C2H5)4N]3[Yb(NCS)6]·(C6H6), for example, is monoclinic, space group P21⁄c, a=19.458(12), b=14.046(6), c=18.288(7) Å, β=91.28(4)°, Z=4, and the final R value obtained was 0.064. The other seven crystals are isomorphous with each other. The central metal atom is in an octahedral hexa-coordination geometry: six nitrogen atoms of isothiocyanate ions are ligated to each metal atom. Each solvent molecule is arranged betweeen each pair of neighboring metal atoms along the [1 \bar1 0] axis in each crystal. The cations are arranged approximately between each pair of metal atoms along the [0 1 1], [0 \bar1 1], and [1 1 0] axes, respectively. They were stable for more than a few weeks at room temperature; however, when heated at about 80–90 °C, their guest molecules were lost.
Solvent Influence on the Circular Dichroism Spectrum of Potassium Ethylenediaminetetraacetatocobaltate(III)
Authors: Taura Toshiaki
Published: July 2006

The circular dichroism (CD) spectrum of optically active potassium ethylenediaminetetraacetatocobaltate(III), (+)-K[Co(edta)]·2H2O, was measured in water and a variety of organic solvents: ethylene glycol, methanol, formamide, ethanol, 2-propanol, chloroform, nitromethane, dichloromethane, dimethyl sulfoxide, acetonitrile, N,N-dimethylformamide, benzonitrile, N,N-dimethylacetamide, and acetone. The spectra in organic solvents were obtained for the solutions of the complex anion, which were prepared by the addition of a macrobicyclic polyether, cryptand 222. It was found that the peak positions and intensities of the CD bands are markedly influenced by the solvent molecules and this solvent influence on the peak position is linearly correlated to the influence on the corresponding first d–d absorption spectrum. Therefore, the solvent influence on the CD spectrum of this complex is suggested to be caused by the change in the d–d transition energy of this Co(III) complex anion. Furthermore, the positions and intensities of the CD peaks were also correlated with the electrophilic ability (the acceptor number: AN) and the bulk polarity (the dielectric constant) of the solvent, respectively. It is proposed that the inherent CD spectrum of [Co(edta)]− that is not solvated could be estimated on the basis of this correlation.
Mechanism of the Reaction of (Arylthio)trimethylgermanes with 1-Aryl-1-bromoethanes—Kinetic and Stereochemical Studies—
Authors: Kozuka Seizi , Nitta Takemi , Tamura Shoji , Tagaki Waichiro
Published: July 2006

Kinetic and stereochemical studies have been conducted on the reaction of (arylthio)trimethylgermanes with 1-aryl-1-bromoethanes. The reaction has been found to obey a first-order kinetic equation. The rates of the reaction of the substituted arylethanes were well-correlated with σ+ constants. Optically active 1-bromo-1-phenylethane gave racemic phenyl 1-phenylethyl sulfide by the reaction with trimethyl(phenylthio)germane. An SN1 ionization of 1-aryl-1-bromoethanes has been suggested as the reaction mechanism.
Studies of the Hydrous Niobium(V) Oxide Ion Exchanger. V. Effect of Heat Treatment on the Sodium Isotopic Exchange Rates between Hydrous Niobium(V) Oxide in Na+ Form and Aqueous Solutions
Authors: Inoue Yasushi , Yamazaki Hiromichi , Ikeda Mitsuji
Published: July 2006

The effect of a heat treatment was studied on the sodium isotopic exchange rate between the hydrous niobium(V) oxide in the Na+ form and aqueous solutions. The rate was controlled by the particle diffusion of sodium ions and increased with the heat-treatment temperature. The increase in the rate for the exchanger heat-treated at 200 °C was due to a decrease in the effective particle radius brought about by cracks which developed in the particles. A further increase in the rate at temperatures higher than 200 °C could be explained in terms of an increase in the Na+-diffusion coefficient, which was produced by an increase in the pore size responsinble for the movement of sodium ions.
The Mechanism of Seasonal Variation in the Size Distributions of Atmospheric Chloride and Nitrate Aerosol in Tokyo
Authors: Hara Hiroshi , Kato Tsuyoshi , Matsushita Hidetsuru
Published: July 2006

The volatility of ammonium chloride and nitrate was demonstrated to be responsible for the seasonal variation in size distributions that is the atmospheric fine-mode (<2 μm) chloride and nitrate aerosol were predominant in winter, but the coarse mode (>2 μm) was more pronounced in summer. An ion-balance examination and heating of winter aerosol samples demonstrated that fine-mode chloride and nitrate species are ammonium salts which are volatile at summer atmospheric temperatures. Both volatilized and unvolatilized concentrations of these chloride and nitrate species were determined both in winter and in summer to prove that the gas–solid interconversion took place in the atmosphere. The log-normal distributions of the ionic-component concentrations and the seasonal changes in the ionic composition of fine-mode aerosol were also discussed.
Electrochemical Behavior of Azoxybenzene-4,4′-disulfonamide at Pyrolytic Graphite Electrode
Authors: Goyal R N , Bhargava Sandhya
Published: July 2006

The electrochemical reduction of azoxybenzene-4,4′-disulfonamide has been studied in the Britton Robinson buffers of pH range 3.0–10.6 at a pyrolytic graphite electrode. The electroreduction was found to occur in a single well defined 4e, 4H+ peak. The hydrazo compound has been identified as the main product of the electrode reaction.
Solvent and Electrode Kinetic Effects on Cathodic Reduction of I3−+2e→3I− in Some Pure and Mixed Dipolar Aprotic Solvents
Authors: Bhattacharya Swapan , K. Kundu Kiron
Published: July 2006

Exchange current densities (i0) of the redox reaction I3−+2e−=3I− have been determined at 25 °C on platinum (Pt) and graphite (C) electrodes in acetonitrile (ACN), propylene carbonate (PC), N,N-dimethylformamide (DMF), and their binary mixtures by potentiostatic polarization studies under near equilibrium conditions. The studies in pure solvents have also been extended to 15 and 35 °C and also on platinized graphite (C)Pt electrode. The kinetic solvent effect data at 25 °C have been analyzed in the light of relative solvation of I2 and transition state (TS) as reflected from the previously reported transfer free energies (ΔGt°) of I2 and that of TS derived therein for the respective solvent systems. The electrocatalytic activities of (C)Pt electrode in different solvent systems are found to be of the same order as that of Pt electrode possibly because of its large roughness factor. But the observed energies of activation (Ea) being of the order C>>C(Pt) ≈Pt suggest that graphite is intrinsically a weaker electrocatalyst than both the (C)Pt and Pt electrodes, which are however equivalent to each other so far as electrocatalytic activity is concerned. Moreover, while the electrocatalytic activity of Pt and (C)Pt electrodes is found to be in the order ACN>PC>DMF, that of C is ACN>DMF>PC, which have been ascribed to result from the differential adsorption propensities of the solvent molecules with respect to Pt and C surfaces respectively.
Amorphous and Crystalline Peroxopolytungstic Acids Formed from Tungsten and Hydrogen Peroxide
Authors: Okamoto Hiroshi , Ishikawa Akira , Kudo Tetsuichi
Published: July 2006

Peroxopolytungstic acids, WO3·xH2O2·yH2O (0≤x≤1), formed directly from tungsten and hydrogen peroxide are found to be crystalline or amorphous depending on x.
Synthesis of Five-Membered Cyclic Ketones Using Potassium Tetracarbonylferrate(2—)
Authors: Yamashita Masakazu , Uchida Masaya , Tashika Haruyoshi , Suemitsu Rikisaku
Published: July 2006

Various five-membered cyclic ketones were prepared from 1,4-dihaloalkanes and potassium tetracarbonylferrate(2—) in moderate to high yields. However, the yields of six- or seven-membered cyclic ketones from the corresponding dihalides were rather low.
The Dehalogenation of vic-Dihaloalkanes to Alkenes with Sodium Trithiocarbonate or Sodium Dithiocarbonate in the Presence of Phase-Transfer Catalysts
Authors: Sugawara Akira , Nakamura Atsushi , Araki Akitoshi , Sato Ryu
Published: July 2006

The reductive dehalogenation of vic-dihaloalkanes with aqueous sodium trithiocarbonate or sodium dithiocarbonate in the presence of a phase-transfer catalyst gave the corresponding alkenes in high yields under mild conditions.
An Oxidative Dimerization of Anthrones by Oxygen-Metal Acetate System
Authors: Yamaguchi Masahiko , Hasebe Koichi , Uchida Minoru , Higashi Hirofumi , Minami Toru
Published: July 2006

Anthrones were oxidatively dimerized with oxygen in the presence of Pb(OAc)2 giving 9,9′-bianthracene-10,10′(9H,9′H)-diones. The dimerization proceeds under mild reaction conditions, and gives products in good yields. Binaphthacenedione and bipentacenedione were also synthesized.
Kinetics and Mechanism of the Substitution of β-Diketonates for Acetylacetonate in Bis(acetylacetonato)(trimethyl phosphate)dioxouranium(VI)
Authors: Udagawa Yoshiko , Tomiyasu Hiroshi , Jung Woo-Sik , Eom Tae Yoon , Fukutomi Hiroshi
Published: July 2006

Kinetics of the substitution of β-diketonates for one acetylacetonate in UO2(acac)2tmp (acac=acetylacetonate, tmp=trimethyl phosphate) has been studied in tmp by spectrophotometric methods. The reactions proceed through intermediate complexes UO2(acac)2HB, where HB denotes various β-diketones. The formation of the intermediates are followed by intramolecular proton transfer processes from coordinated HB to one of two acac in UO2(acac)2HB. The proton-transfer step for various HB can be classified into two groups owing to the difference in the values of rate constants k2, i.e. the substitutions of Hbza, Hhpd, and Hdbm and those of Hbta, Htta, and Htfa, k2 of the former group giving the order of 10−3 s−1, while that of the latter the order of 10−1 s−1, at 25 °C, where Hbza=benzoylacetone, Hhpd=3,5-heptanedione, Hdbm=dibezoylmethane, Hbta=benzoyltrifluoroacetone, Htta=2-thenoyltrifluoroacetone, and Htfa=trifluoroacetylacetone. This can be well explained in view of the acidity of β-diketones. The addition of amphiprotic solvents, such as water and alcohols, accelerates the substitution rates, and the observed first-order rate constant kobsd is expressed by kobsd=k2+kc[solvent]. In the case of the addition of alcohols, kc increases in the order: n-BuOH<i-PrOH<n-PrOH<EtOH<MeOH. This is the reverse order of autoprotolysis constants of these alcohols. Kinetic isotope effects kcH/kcD for the substitution of Hbza in tmp in the presence of H2O (or D2O) and CH3OH (or CH3OD) were determined to be 2.5 and 1.8, respectively.
Behaviors of the Enthalpies of Mixing and Formation in the System Lead–Indium
Authors: Badawi Walid Ahmad
Published: July 2006

The paper presents results of calorimetric studies on the enthalpies of mixing and formation in the system lead–indium. The enthalpy of formation is negative and becomes more negative at higher composition. The partial enthalpy of formation of lead is negative but increases at higher composition. The partial enthalpy of formation of indium is also negative and decreases with increasing the composition. The enthalpy of formation displays a considerable temperature dependence which seems to be smaller than that observed for the enthalpy of formation in other systems.
Studies of Collectors. XI. The Preparation of Cyclic Polyamine-Type Surfactants and Application to Ion-Flotation Collectors
Authors: Yamada Kimiho , Koide Yoshifumi , Yamanokuchi Hiroshi , Ohmura Masaki , Shosenji Hideto
Published: July 2006

Inclusion-type surfactants bearing cyclic dioxopolyamine (RndoN4, RndoN5) or cyclic polyamine (R12N4, 2.4R-N6, Ls6.8N6) were prepared and then investigated as ion-flotation collectors. The surface tensions of the surfactant solutions were 30–40 dyn cm−1. The molecular areas of the surfactants in the aqueous solutions, as calculated from the Gibbs adsorption isotherm, were discussed in connection with the structures of the RndoN4 and its Cu2+ complex. Heavy metal ions were floated with RndoN4 or RndoN5. The highest floatabilities of Cu2+ and Ni2+ were in the pH range of 10–12, while that of Fe3+ was in the pH range of 6–10. Furthermore, similar characteristics of the metal floatabilities were obtained by using R12N4 and alkylated linear polyamine. The flotation using RndoN4 or RndoN5 was done by the complex formation, but that using R12N4 or 2.4R-N6 was done by the neutralization of the complex with OH−. The selectivities in pH 4–8 were Cu2+>Ni2+>Fe3+>Zn2+ when RndoN4 was used and Fe3+>Cu2+>Ni2+>Zn2+ when RndoN5 was used.
Effects of Polysubstitution on Mesomorphic Properties: Chloro and Methyl Derivatives of N-[4-(4-Substituted benzoyloxy)benzylidene]anilines
Authors: Hasegawa Hiroyuki , Masuda Tatsuya , Matsunaga Yoshio , Seo Sachiko , Yasuhara Kazuaki
Published: July 2006

The effects of mono-, di-, and trichloro substitution of the aniline moiety on the nematic-isotropic transition temperature of N-[4-(4-X-substituted benzoyloxy)benzylidene]anilines, where X=CH3O, CH3, or Cl, have been studied, while paying particular attention to the vicinal chlorines. While the substituent on the 2 or 3 position of the aniline moiety lowers the transition temperature of the parent compound and the 4-chloro derivative, the 2,3-dichloro derivative shows a temperature higher than that of either the 2- or 3-chloro derivative. Moreover, the transition temperature of the 2,3,4-trichloro derivative exceeds that of the 3,4-dichloro derivative and is a little below that of the 2,4-dichloro isomer. In contrast, the introduction of 4-substituent increases the temperature, regardless of the position(s) of the other substituent(s). Methyl substitution exerts effects closely similar to those described above.
A Simple and Rugged Home-Built Scanning Tunneling Microscope for Operation in Both Air and Liquid
Authors: Sakamaki Kenji , Itoh Kiminori , Fujishima Akira , Gohshi Yohichi , Nakagawa Hidemoto
Published: July 2006

A simple, rugged home-built scanning tunneling microscope for operation in both air and liquid that uses a Z-stage micrometer to provide coarse mechanical positioning is described. The construction of this STM was accomplished at low cost without precision machining. The tunneling current is typically acquired within 10–15 minutes. The atomic resolving power of our STM has been demonstrated by a cleaved HOPG at a 15-Hz scanning rate in air. There was no use of plate-stack-type isolators, due to the high rigidness of the tunneling unit. The STM image of a HOPG in ultrapure water was also observed with a glass-coated tip. Images of a pc-Ag electrode in 0.1 mol dm−3 KCl demonstrate stable operation in a liquid solution. The lateral drift was shown to be less than 0.13 nm min−1 for operation in liquid, estimated by subsequent imaging of the same area. This STM is easy to handle and has a suitable design for in situ electrode surface characterization.
Optical and Magnetic Resonance Studies of the Interaction of Metallotetraphenylchlorin and Octaethylporphyrin with Trinitrofluorenone
Authors: Choudhury Biswajit , Chandrashekar T K
Published: July 2006

The interaction of metallo derivatives of tetraphenylchlorin (TPC) and octaethylporphyrin (OEP) with 2,4,7-trinitrofluorenone (TNF) is described in terms of 1 : 1 molecular complexes. The binding constants vary as CuOEP>ZnOEP>CuTPC>ZnTPC and this variation is accounted in terms of the structure of the macrocycle and the substituents presen on it. ESR studies of the complexes reveal that the π-complexation results in changes in the electronic structure of the central metal ion. The magnitude of different proton shifts of the acceptor in 1H NMR spectra of the complexes are used to arrive at the possible solution structure of the complexes.
Generation of Enolates from α,β-Epoxy Sulfoxides with Lithium Dimethylcuprate: A Novel Synthesis of Aldols and Some Trial to Trap the Enolates
Authors: Satoh Tsuyoshi , Sugimoto Atsushi , Itoh Masayuki , Yamakawa Koji
Published: July 2006

Enolates were generated from α,β-epoxy sulfoxides using lithium dimethylcuprate as an electron-transfer reagent. The enolates were trapped with several electrophiles, in which aldehydes reacted with the generated enolates giving aldols in good yields with high regioselectivity.
2A,2B-, 2A,2C-, and 2A,2D-Bis-O-(p-tolylsulfonyl)-β-cyclodextrins
Authors: Fujita Kahee , Ishizu Takashi , Oshiro Kyoko , Obe Ken-ichi
Published: July 2006

A mixture of the title ditosylates was prepared by the reaction of β-cyclodextrin with dibutyltin oxide and tosyl chloride. Each ditosylate was isolated by reversed-phase column chromatography and the structure was assigned on the basis of conversion into a known compound or hydrolysis with Taka amylase A.
(−)-(9Z)-1,9-Heptadecadiene-4,6-diyn-3-ol as a Principal Component of the Resinous Sap of Evodiopanax innovans Nakai, Japanese Name, Takanotsume, and Its Role in an Ancient Golden Varnish of Japan
Authors: Terada Akira , Tanoue Yasuhiro , Kishimoto Daishiro
Published: July 2006

(−)-(9Z)-1,9-Heptadecadiene-4,6-diyn-3-ol was for the first time isolated in high yield (29%) from the resinous sap of Evodiopanax innovans Nakai, Araliaceae. This compound has been associated with the main polymerizable component of an ancient golden varnish. It has also been associated with a phytoalexin and a defense material which produces a water-insoluble coating film by photopolymerization under sunlight for a Takanotsume tree upon being wounded.
Molecular Aggregation Structure of Barium Stearate Monolayer Based on Electron Microscopy
Authors: Kajiyama Tisato , Umemura Kazuo , Uchida Motoko , Oishi Yushi , Takei Ryutaro
Published: July 2006

Aggregation structure of barium stearate monolayers prepared from a benzene solution at various surface pressures was investigated by using a transmission electron microscope. Two-dimensional crystallites of the monolayer were formed even at the surface pressure of 0 mN · m−1. The monolayer crystallites on the water surface became a continuous phase at 25 mN · m−1 and collapsed at 40 mN · m−1. The surface pressure–area isotherm represents an aggregating process of the small two-dimensional crystallites on the water surface, instead of a generally accepted concept on phase transitions among gas, liquid, and solid phases.
An Exceptionally-Large Negative Halochromism in 2-(4-Ethoxycarbonylphenyl)2,3-dihydro-3,3-dimethyl-5,6-cycloheptapyrazoledione, a Hinopurpurin Derivative
Authors: Mori Akira , Li Zhi-Hong , Takeshita Hitoshi
Published: July 2006

2-Aryl-2,3-dihydro-3,3-dimethyl-5,6-cycloheptapyrazolediones with an electron-releasing group at C-4 on the benzene ring showed a bathochromic shift in acid solution, whereas the 4-ethoxycarbonylphenyl derivative showed a negative halochromism; 484 nm in ethyl acetate, 517, 566, and 600(sh) nm in trifluoroacetic acid, and 455 nm in coned sulfuric acid.
New Approaches to Tetracyanoquinodimethane
Authors: Yamaguchi Shunro , Miyamoto Kazuyuki , Hanafusa Terukiyo
Published: July 2006

New synthetic methods of tetracyanoquinodimethane from terephthaloyl dichloride were presented. Conversion of terephthaloyl dichloride to 1,4-bis(dicyanobenzoyloxymethyl)benzene, followed by debenzoyloxylation and succeessive oxidation afforded TCNQ.
High-Resolution Solid-State 31P NMR of Alkali Phosphates
Authors: Hayashi Shigenobu , Hayamizu Kikuko
Published: July 2006

High-resolution solid-state 31P NMR spectra have been measured for inorganic alkali phosphates with different condensations in the PO4 units, and the isotropic chemical shift and anisotropy have been determined. The isotropic chemical shifts in alkali orthophosphates do not correlate directly with the cation size. The hydration effects have been carefully examined by means of a 1H decoupling experiment and by the heat treatment of the materials, accompanied by thermogravimetric analysis. Hydration causes an upfield shift in Na3PO4, K3PO4, and Na4P2O7, while it causes a downfield shift in Rb3PO4 and Cs3PO4. All the five peaks observed in the K4P2O7 sample can be ascribed to anhydrous species; this is in contrast to the findings of previous works. The field-dependence experiments definitely demonstrate that the splittings in K4P2O7 and (KPO3)n are caused by inequivalent sites.
Fluorescence Studies on the Phase Dependence of Interactions between a Tripeptide, Lys–Trp–Lys, and Dimyristoylphosphatidylserine
Authors: Yamashita Shoji , Szabo Arthur G , Krajcarski Donald T , Yamasaki Nobuyuki
Published: July 2006

Interactions of a basic tripeptide, lysyl-tryptophyl-lysine (LTL) with dimyristoylphosphatidylserine (DMPS) were investigated by fluorescence spectroscopy. An interacting LTL–DMPS complex assumes two distinctly different conformations in the lipid bilayer depending on the thermotropic phase of lipid. At temperatures below the gel–liquid crystalline phase-transition temperature (Tc), LTL binds to the polar head groups of DMPS through electrostatic force, and the tryptophan residue is located on the surface of the membrane because of the rigidity of the head groups. Above Tc, it assumes a conformation such that the tryptophan residue slips deeply into the DMPS bilayer. The temperature dependence of the fluorescence quenching by acrylamide supported the penetration of the tryptophan upon the phase transition of DMPS. A fluorescence decay analysis based on the photophysical deactivation mechanism of tryptophan residue has revealed a peculiar interaction of LTL with DMPS in the bilayer.
Response and Application in Dipolar Aprotic Solvents of Ion-Selective Electrodes Based on Polyacrylamide Modified with Acyclic Poly(oxyethylene) Derivatives
Authors: Nakamura Toshio , Higuchi Hisakazu , Izutsu Kosuke
Published: July 2006

The response of organic polymer membrane electrodes, constructed by coating a platinum disk with polyacrylamide (PAA) coupled to acyclic poly(oxyethylene) derivatives, tetraethylene glycol monododecyl ether (POE4) and hexaethylene glycol monododecyl ether (POE6) was studied in acetonitrile (AN) and N,N-dimethylformamide (DMF). The PAA–POE4 electrode showed Nernstian response to the lithium ion in AN and the magnesium and barium ions in DMF, while the PAA–POE6 electrode showed near Nernstian response to the barium ion in DMF. The PAA–POE4 electrode was applied to study the complexation of the lithium ion in AN with DMF. The formation constants, β1=17 and β2=1.2×102, obtained agreed well with the values obtained previously with an univalent cation sensitive glass electrode. The response of the PAA-POE4 electrode in barium bis(2-ethylhexyl) sulfosuccinate (Ba(DSS)2)–DMF solution has been studied and the results are explained by taking the conductometrically determined association constant (K1A=5.2×102) between Ba2+ and DSS− ions.
Peptide Synthesis in Aqueous Solution. IV. Preparation and Properties of [p-(Benzyloxycarbonyloxy)phenyl]dimethylsulfonium Methyl Sulfate (Z-ODSP), [p-(t-Butoxycarbonyloxy)phenyl]dimethylsulfonium Methyl Sulfate (Boc-ODSP) and [p-(9-Fluorenylmethyloxycarbonyloxy)phenyl]dimethylsulfonium Methyl Sulfate (Fmoc-ODSP) as Water-Soluble N-Acylating Reagents
Authors: Azuse Ikunori , Tamura Masahiro , Kinomura Keisuke , Okai Hideo , Kouge Katsushige , Hamatsu Fumio , Koizumi Tatsuya
Published: July 2006

In order to increase the applications of the water-soluble active ester method, water-soluble acylating reagents, [p-(benzyloxycarbonyloxy)phenyl]dimethylsulfonium methyl sulfate, [p-(t-butoxycarbonyloxy)phenyl]dimethylsulfonium methyl sulfate and [p-(9-fluorenylmethyloxycarbonyloxy)phenyl]dimethylsulfonium methyl sulfate, were synthesized from of p-hydroxyphenyldimethylsulfonium methyl sulfate. These compounds had high solubility (more than 30%) in water and were found to act as excellent water-soluble acylating reagents for the synthesis of N-benzyloxycarbonyl, N-t-butoxycarbonyl, N-9-fluorenylmethyloxycarbonyl amino acid derivatives in aqueous solution. They converted dipeptides to N-acyl-dipeptides in aqueous media as well as amino acids. In addition, they were found to be efficient reagents for protecting the side chains of lysine, ornithine, and cysteine.
Sulfur Nitrides in Organic Chemistry. 18. Preparation and Reduction of Benzo[1,2-c:3,4-c′:5,6-c″]tris- and Benzo[1,2-c:3,4-c′]bis[1,2,5]thiadiazole. A Convenient Route to Benzenehexamine and 1,2,3,4-Benzenetetramine
Authors: Mataka Shuntaro , Eguchi Hisao , Takahashi Kazufumi , Hatta Taizo , Tashiro Masashi
Published: July 2006

Benzotris- (3) and benzobis[1,2,5]thiadiazole (4) were prepared in a moderate yield, respectively, by the reaction of tetrasulfur tetranitride (5) with halocatechols (6) and -resorcinols (7). The reduction of 3 and 4 with Sn powder in a mixture of concentrated hydrochloric acid and dioxane gave benzenehexamine (1) and 1,2,3,4-benzenetetramine (2a) and its 5-methyl derivative (2b) in good yields, as a stable tri- (1·3HCl) and dihydrochloride (2·2HCl), respectively.
Enzymatic Synthesis of Specifically Modified Linear Oligosaccharides from γ-Cyclodextrin Derivatives. Study on Importance of Active Sites of Taka Amylase A
Authors: Fujita Kahee , Tahara Tsutomu , Koga Toshitaka , Imoto Taiji
Published: July 2006

Specifically modified linear oligosaccharides were prepared by enzymatic hydrolysis of 6- or 2-O-substituted γ-cyclodextrin by Taka amylase A. These results suggest that the importance of the interactions between hydroxyl groups and the subsites (P–V) of Taka amylase A decreases in the following order; for C-6-OH, S>R>T>Q, U and for C-2-OH, R,S>T>Q, U.
Unusual Reactivity of Purinophanes Due to Stereoelectronic Effect
Authors: Sakata Yoshiteru , Higuchi Hiroyuki , Doyama Kazuo , Higashii Takayuki , Mitsuoka Miho , Misumi Soichi
Published: July 2006

Four types of purinophanes (1, 2, 7, and 10) where a 6-thiopurine ring is bridged between S6- and 9-positions or between S6- and 7-positions were synthesized. Among them (6,9)purinophanes (1, 7, and 10) showed unusual high reactivity toward nucleophiles (MeNH2, Me2NH, OH−) at 6-position to give acyclic compounds. The increased rate constants of these compounds against (6,7)purinophanes 2 and 9-methyl-6-(methylthio)purine could not be explained by molecular strain, neighboring group participation, or some electronic effect due to faced π-systems, but successfully explained by the stereoelectronic effect proposed by Deslongchamps. The rate of the reactions in 1, 7, and 10 was increased with an increase in rigidity of the tetrahedral intermediate where lone pairs of two adjacent heteroatoms orient antiperiplanar to the departing group.
The Effect of Alternative Magnetic Field on the Pigment Ejection from Magnetic Anisotropic Gel Beads
Authors: Sakai Yasuzo , Taguchi Hidefumi , Takahashi Fujio
Published: July 2006

Magnetic anisotropic gel beads (MA gel beads) were prepared by the gelation of a ferrite suspension in a static magnetic field. MA gel beads were found to oscillate in an alternating magnetic field. This oscillation can possibly reduce the thickness of the diffusion layer on the interface between the gel beads and the surrounding solution, so that the substance can be transferred more quickly across the gel–liquid interface. MA gel beads consisted of alginate gel containing ferrite powder and toluidine blue as a pigment. MA gel beads were loaded into a dual glass tube to make a column bed, which was inserted into a coreless coil which produced the alternating magnetic field. The concentration change of the pigment in the effluent from the column was measured during a lapse in time with repeating off and on the input of the alternating magnetic field. The pigment concentration in the effluent upon exposure to the alternating magnetic field increased to twice the maximum value obtained without a magnetic field. The stronger was the static magnetic field at the time of gelation and the alternating magnetic field, the larger was the increase in pigment concentration in the effluent. Also, the higher was the concentration of ferrite in gel beads, the larger was the increase in pigment concentration in the effluent.
Synthesis and Spectral Analysis of Some Schiff Bases Containing Long Alkyl Chains
Authors: Senapati Sushree , Mishra Bijaya Kumar , Behera Gopa Bandhu , Mahendroo Prem Prakash
Published: July 2006

Schiff bases containing hydrophobic alkyl chains have been synthesized and the IR, 1H NMR, 13C NMR, and mass spectral data of some of the compounds have been reported.
Syntheses, Spectroscopic Properties, Crystal Structures, and Antitumor Activities of the Optically Isomeric Mandelate Chelates, Mandelato(trans-1,2-diaminocyclohexane)platinum(II)
Authors: Miyamoto T Ken , Okude Kojiro , Maeda Kazuyuki , Ichida Hikaru , Sasaki Yukiyoshi , Tashiro Tazuko
Published: July 2006

The four optical isomers of mandelato(trans-1,2,-diaminocyclohexane)platinum(II) have been prepared. The CD and NMR spectra of these compounds in solution indicate that the mandelate coordinates to platinum(II) to form a five-membered chelate ring. The X-ray crystal structure analyses of a pair of diastereomers, (R)-mandelato[(1R,2R)-1,2-diaminocyclohexane]platinum(II) and (S)-mandelato[(1R,2R)-1,2-diaminocyclohexane]platinum(II), have confirmed that the skeletal configuration of (R)- or (S)-mandelic acid is retained during the chelation of platinum(II). As a whole, the structural features of both diastereoisomers are analogous to each other. However, slight differences in hydrogen bonding are noticeable in relation to the solubilities. A preliminary animal test against mice leukemia L1210 was carried out using these compounds. The four isomers show different activities. All these facts together support the conclusion that the chiralities of both ammine (carrier) and mandelate (leaving group) influence the antitumor activities of the platinum agents.
Studies on Tetramethyldithizone Isomers and Their Reactions with Metal Ions
Authors: Kiwan A M , Hassan F M , Hamdan W
Published: July 2006

Six bis(dimethylphenyl) analogues of dithizone are prepared, characterized and their reactions with metal ions in a two phase system are reported. The extraction equilibria of their complexes with Cd(II), Co(II), Hg(II), Pb(II), Tl(I), Zn(II), and Bi(III) as well as their spectral characteristics are described. Complete extraction of these metal chelates requires higher pH’s than those needed for the unsubstituted dithizone. The molar absorptivities of Bi(III) complexes with bis(3,4-dimethylphenyl)-, and bis(3,5-dimethylphenyl) analogues are higher than the corresponding value of Bi(III) dithizonate. The molar absorptivities of Cu(II) and Hg(II) (in CCl4) complexes with bis(3,5-dimethylphenyl) analogue are also higher than the corresponding values of the unsubstituted dithizone complexes.
125Te and 129I Mössbauer Spectroscopic Studies of the Tetragonal and Orthorhombic Forms of Tellurium(IV) Oxide
Authors: Sakai Hiroshi , Maeda Yutaka
Published: July 2006

125Te and 129I Mössbauer spectra have been measured for the tetragonal (α) and orthorhombic (β) forms of TeO2. The Mössbauer data show that there are no significant differences between the two modifications in either the electronic structure or the chemical bonding of the tellurium atoms; this is consistent with the crystallographic data. From a comparison of the Mössbauer data for 125Te with those for 129I, we have concluded that the 129I daughter nucleus, produced by the nuclear β− decay of 129Te, is present in the same lattice environment as the parent 129Te nucleus in TeO2. A Cu125I crystalline compound has been used as the Möossbauer source of 125Te, which emits a single line of resonance γ-ray. The values of the isomer shift and line width for the source are found to be −0.13 mm s−1 relative to the ZnTe standard absorber and 6.53 mm s−1 respectively.
Kinetics and Mechanism of Oxidation of Amino Acids by Dichloramine T
Authors: Gowda B Thimme , Rao P Jagan Mohana
Published: July 2006

Kinetics of oxidations of several amino acids (alanine, leucine, aspargine, glutamine, and proline) by N,N-dichloro-p-toluenesulfonamide (generally known as dichloramine-T) have been studied in 1:1 (v/v) water–methanol medium in the presence of perchloric acid. The oxidations of alanine and leucine showed second order kinetics in [oxidant], first order in [amino acid] and inverse fractional order in [H+] over the entire range of [HClO4](0.0005–0.10 mol dm−3) used. But the kinetics of oxidations of aspargine, glutamine, and proline were [H+] dependent. The rate dependence in [oxidant] was second and first orders in [H+] ranges 0.0005–0.005 mol dm−3 and 0.005–0.10 mol dm−3, respectively. The kinetics in [amino acid] for these oxidations were also different. Variation in ionic strength of the medium or addition of the reduced product of the oxidant had no or negligible effects on the rates of reactions. Decrease in dielectric constant of the medium by increasing the methanol composition of the solvent decreased the rate in all the cases. Activation parameters have been computed from the Arrhenius plots. Plausible mechanisms consistent with the observed kinetics have been discussed.
Solvent Effect on Hydrogen Bonding Interaction between 5,6,7,8-Tetrahydro-2-naphthol in the Ground and Excited States and Triethylamine
Authors: Pal T K , Mallik G K , Ganguly T , Banerjee S B
Published: July 2006

In the ground state 5,6,7,8-tetrahydro-2-naphthol (ThOH) forms with triethylamine (TEA) simple hydrogen bond, hydrogen-bonded ion pair or solvent-separated ion pair complex depending on the polarity of solvents. Fluorescence emission of ThOH is quenched by TEA in all solvents. The quenching rate constant kq is large in weakly polar solvents than in highly polar solvents and there is no evidence of formation of solvent-separated ion pair in latter solvents. It is suggested that restricted electron delocalization in excited ThOH molecule lowers the tendency of deprotonation of the OH group. The likely pathway of energy depletion is through intermediate singlet contact CT exciplex of the type A−D+ between ThOH and TEA.
Oxidation of Indigo Carmine by N-Haloarenesulfonamidates: A Kinetic Study
Authors: Puttaswamy  , Mahadevappa Dandinasivara Siddalingaiah , Rangappa Kanchugarakoppal Subbegowda
Published: July 2006

Kinetics of oxidation of indigo carmine (IC) by sodium N-haloarenesulfonamidates (RNXNa, where R=CH3C6H4SO2− or C6H5SO2− and X=Cl or Br) chloramine T (CAT), bromamine T (BAT), chloramine B (CAB), and bromamine B (BAB) in alkaline buffer (pH 9–11) has been followed spectrophotometrically at λmax=610 nm. Rate law, –d[IC]/dt=k[OX]0[IC]0[OH−]x where x<1, is obeyed. The reaction products, benzenesulfonamide and toluenesulfonamide retard the rate. Sulfonated anthranilic acid formed was quantitatively determined. Variation of ionic strength or dielectric constant of medium and addition of halide ions have no effect on the reaction. A two pathway mechanism is proposed in which the hypohalous acid (HOX) and the anion of N-haloamine RNX− interact with the substrate in rate limiting steps. The rate increases in the order: BAT>BAB>CAT>CAB, which is attributed to the difference in electrophilicities of halogen cations Br+ and Cl+ involved in the oxidation process and the ease with which these species are formed in reactions.
Photoelectric Effect of Metallophthalocyanine Derivatives
Authors: Hirohashi Ryo , Tanaka Toyohide , Koshijima Yoshihiro , Kamiyama Masafumi
Published: July 2006

The photoelectric effect of copper phthalocyanine derivatives (CuPcR4) in a dispersed system in polycarbonate (PC) has been investigated with a sandwich-typed cell configuration of Au/CuPcR4 in PC/Ag. When the incident irradiation was directed through the Ag electrode, the photocurrent and photovoltage were observed for all CuPcR4 cells. It has been concluded that the photoelectric characteristics are not missed and that the values of the work functions of all CuPcR4 derivatives are between 4.67 and 4.78 eV.
The Preparation and Stereoselectivity of [Cr(l- or d-ala)x(l-leu)3−x] and the Possibility of the Optical Resolution of Dl-Alanine
Authors: Yoshimura Yoshitake , Kataoka Yuichi , Moriishi Hirobumi , Watanabe Tetsuo , Oki Hisaya
Published: July 2006

fac-(+)546-[Cr(l-ala)2(l-leu)]·1.5H2O and fac-(−)546-[Cr(d-ala)2(l-leu)]·1.5H2O were prepared by the method using an ethanol solution, with [Cr(l-leu)2(NCS)(OH2)](leu=leucinato) with l- or d-alanine used as the starting material respectively. Also, fac-[Cr(l- or d-ala)(l-leu)2]·2H2O was obtained from the filtrate, the standing temperatures were 5, 25, 40, and 55 °C. The optical purity of fac-(Λ)-[Cr(l- or d-ala)(l-leu)2]·2H2O increases with the rise in the standing temperature. In the case of Dl-alanine, [Cr(l-ala)2(l-leu)]·1.5H2O and [Cr(d-ala)(l-leu)2]·2H2O were obtained during heating and from the filtrate respectively. By using this procedure, the possibility of the optical resolution of Dl-alanine was shown.
Oxidation Using Quaternary Ammonium Polyhalides. IV. Selective Oxidation of Sulfides to Sulfoxides with Benzyltrimethylammonium Tribromide
Authors: Kajigaeshi Shoji , Murakawa Katsuya , Fujisaki Shizuo , Kakinami Takaaki
Published: July 2006

The reaction of sulfides with a stoichiometric amount of benzyltrimethylammonium tribromide and aqueous sodium hydroxide in dichloromethane at room temperature or in 1,2-dichloroethane under reflux gave the corresponding sulfoxides in good yields.
Generation and Chemical Fate of 2,2,2-Trifluoro-1-phenylsulfonylethyl Carbanion
Authors: Uneyama Kenji , Momota Makoto
Published: July 2006

2,2,2-Trifluoro-1-phenylsulfonylethyl carbanion generated by the action of LDA in THF–HMPA can be methylated and iodinated, where the tetraethylammonium cation plays an essential role for the stabilization of the carbanion.
Simple and Efficient Synthesis of α-Allenic Alcohols and Their Novel Conversion into 1-Aryl-3-formyloxy-1,3-butadienes
Authors: Iyoda Masahiko , Kanao Yoshiaki , Nishizaki Minoru , Oda Masaji
Published: July 2006

Reactions of carbonyl compounds with 3-bromo-1-propyne in the presence of SnCl2·2H2O and LiI·3H2O gave α-allenic alcohols in moderate yields together with small amounts of β-acetylenic alcohols. The α-allenic alcohols can be converted into 1-aryl-3-formyloxy 1,3-butadienes, novel 1,3-butadiene derivatives.
Synthesis of 2-[1-(Alkoxycarbonyl)alkyl]-3-methylbenzothiazolines and 3-Methyl-2-(2-oxoalkyl)benzothiazolines by the Direct Alkylation of Lithium Enolates with 3-Methylbenzothiazolium Salts
Authors: Chikashita Hidenori , Takegami Naoto , Yanase Yoshiyuki , Itoh Kazuyoshi
Published: July 2006

A variety of lithium enolates derived from esters and ketones could be readily alkylated with 3-methylbenzothiazolium salts to give the novel α-(benzothiazolinyl) esters and ketones, 2-[1-(alkoxycarbonyl)alkyl]3-methylbenzothiazolines and 3-methyl-2-(2-oxoalkyl)benzothiazolines in good yields, respectively.
The Reaction of α,β-Acetylenic Ketones with Aroylhydrazines
Authors: Holla B Shivarama , Udupa K Venkatramana , Sridhar K R
Published: July 2006

Reaction of 3-(5-nitro-2-furyl)-1-aryl-2-propyn-1-ones (1) with aroylhydrazines (2) furnished 1-aroyl-3-(5-nitro-2-furyl)-5-aryl-5-hydroxy-2-pyrazolines (5) rather than the expected pyrazoles 3 or 4. On acid-catalyzed hydrolysis these hydroxypyrazolines are converted into the known 3-(5-nitro-2-furyl)-5-aryl-1H-pyrazoles (6). The structural elucidation of the products was carried out on the basis of analytical and spectral data. The newly synthesized nitrofuran derivatives are screened for their antibacterial properties against Gram-positive and Gram-negative bacteria. Most of them showed significant activity.
Electronic Conduction in Solid Nitrobenzene Containing Nitrobenzene Anion Radical and Tetrabutylammonium Perchlorate
Authors: Suga Kosaku , Takemura Hirofumi , Fujihira Masamichi
Published: July 2006

The electric conductivities of frozen nitrobenzene containing various amount of tetrabutylammonium perchlorate and nitrobenzene anion radical were measured. The conductivity increased markedly with the concentration of the nitrobenzene anion radical. The mechanism of the electric conduction of the nitrobenzene is discussed and it is concluded that at low concentration of anion radical the increase of the electric conductivity is due to electronic conduction by a hopping mechanism. The rate constant of electron transfer (hopping) between any nearest neighbored sites is about 105 s−1 at −15 °C, which is smaller by 2 orders than that in hypothetical liquid nitrobenzene at the same temperature.
Mesomorphic Properties of Dialkyl N,N′-[1,4-Phenylenebis(methylidyne)]bis[4-aminobenzoates]
Authors: Matsunaga Yoshio , Matsuzaki Hiroyuki
Published: July 2006

The mesomorphic behavior of fourteen dialkyl N,N′-[1,4-phenylenebis(methylidyne)]bis[4-aminobenzoates] has been examined by optical microscopy and differential scanning calorimetry in order to make a comparison with the behavior of N,N′-[1,4-phenylenebis(methylidyne)]bis[4-alkylanilines] and to study the effects of branching of the ester alkyl groups. Among the results obtained, the following may be particularly important: (1) the unbranched alkyl ester is generally less polymesomorphic than the corresponding alkyl compound, (2) mesophase(s) is completely eliminated by the 1-methylation, and (3) the 3-methylbutyl, 3-methylpentyl, and 4-methylpentyl esters are more polymesomorphic than the unbranched alkyl esters.
Formation of Hydrotalcite–Acrylate Intercalation Compounds and Their Heat-Treated Products
Authors: Tanaka Masahito , Park In Yong , Kuroda Kazuyuki , Kato Chuzo
Published: July 2006

Hydrotalcite-like compounds (HT), layered double hydroxides with a few kinds of interlayer anions (X=CO32−, Cl−, and NO3−) were allowed to react with acrylate anions in order to prepare a novel inorganic–organic interstratified layered material by anion exchange. When HT–CO3 was used the anion exchange reaction did not occur. When HT–NO3 was employed the reaction proceeded to form a HT–acrylate intercalation compound. The formation of the intercalation compound from HT–Cl was observed only under a reaction condition using a concentrated acrylate solution. When the intercalation compound was heated at 80 °C with the addition of an initiator, the interlayer acrylate anions were polymerized to form a HT–polyacrylate intercalation compound.
Metal Complexes of Peptides. IV. Cobalt(III) Complexes with β-Alanyl-l-histidine (Carnosine) Functioning as a Quadridentate Ligand
Authors: Ama Tomoharu , Kawaguchi Hiroshi , Uchijima Masato , Koine Norio , Yasui Takaji
Published: July 2006

Three cobalt(III) complexes containing β-alanyl-l-histidine (or carnosine: H2car), [Co(car)(L)]+ (L=en) and [Co(car)(L)]− (L=ox2− or CO32−), were newly prepared and characterized on the basis of their 13C NMR, UV and visible absorption, and circular dichroism spectra. In these complexes, the carnosine coordinates to a cobalt(III) ion as a quadridentate ligand in a meridional form with respect to the peptide chain. In the pH range of 0–6, these complexes exhibited the visible absorption spectral changes with pH. These changes are attributed to the protonation on the oxygen in β-alanyl moiety of the coordinating carnosine and the pKa values of [Co(car)(en)]+ and [Co(car)(ox)]− were estimated as ca. 1.5. The spectral behaviors of the present complexes were compared with that of [Co(Hcar)(en)(OH2)]2+, in which the carnosine functions as a terdentate ligand.
Tetrakis[3-(diethylamino)propyl]- and Tetrakis[3-(diethylmethylammonio)propyl]phthalocyanines: The First Amphiphilic Phthalocyanines
Authors: Kobayashi Nagao , Ojima Fumihiro , Osa Tetsuo , Vigh Steve , C. Leznoff Clifford
Published: July 2006

The first amphiphilic cobalt (III) and copper phthalocyanines (V) have been prepared and are characterized by UV-absorption and magnetic circular dichroism (MCD) spectra in water and organic solvents and in their mixtures. These phthalocyanines exist as dimers in water and as monomers in some organic solvents. Monomer–dimer equilibrium was affected by solvent polarity (or hydrophobicity); with lower cosolvent polarity favoring formation of monomers. Cyclic voltammetry suggests that III adsorbed onto glassy carbon (GC) from an aqueous or acetonitrile (AN) solution in monomeric, irrespective of its state in solution. The CoII/I redox potential of III shifts anodically by adsorption onto GC, and this shift is larger when adsorbed from an AN solution than from an aqueous solution. Electroreduction of oxygen occurs at more positive potential at III-adsorbed GC in plain solution than at bare GC in III-dissolved solution.
Preparation and Spectroscopic Characteristics of Geometrical Isomers of Bis[1,2-bis(dimethylphosphino)ethane]cobalt(III) Complexes with Thiolate Ligands
Authors: Konno Takumi , Bai Zhi-Ping , Okamoto Ken-ichi , Hidaka Jinsai
Published: July 2006

The thiolato cobalt(III) complexes, [Co(SR)2(dmpe)2]+, where R denotes CH3, C2H5, or CH2C6H5 and dmpe denotes 1,2-bis(dimethylphosphino)ethane, were newly prepared from trans-[CoCl2(dmpe)2]+ and monothiolate ligands. The cis and trans isomers were formed for R=CH3 and CH2C6H5, while only the trans isomer was formed for R=C2H5. These isomers were assigned on the basis of the 1H NMR (500 MHz) and absorption spectra in comparison with those of the newly prepared [Co(SCH2CH2S)(dmpe)2]+ complex. The trans isomer showed the sulfur-to-cobalt charge-transfer band at lower energy than that of the cis isomer.
Preparation of 3(2H)-Furanones from 2-Propynyl Alcohol, CO, and Phenyl Halides under CO2 Atmosphere Catalyzed by Transition Metal Complexes
Authors: Inoue Yoshio , Ohuchi Kunihiro , Yen I-Fang , Imaizumi Shin
Published: July 2006

The novel synthetic method for 2,2-dimethyl-5-phenyl-3(2H)-furanone (bullatenone) from 2-methyl-3-butyn-2-ol, CO, and phenyl halides in the presence of a catalytic amount of transition metal complexes under the influence of CO2 has been described. It was revealed that there was the intermediate formation of an acetylenic ketone from the acetylenic alcohol, CO, and the phenyl halide followed by the formation of a cyclic carbonate from the acetylenic ketone and CO2 which underwent the decarboxylative transformation into the 3(2H)-furanone quantitatively.
The Discharge Characteristics of FeOCl in an Aprotic Organic Solvent
Authors: Takehara Zen-ichiro , Kanamura Kiyoshi , Imanishi Nobuyuki , Zhen Chen
Published: July 2006

The discharge reaction of FeOCl was investigated and the discharge products were identified by XRD and EPMA. Lithium and solvent co-intercalate into FeOCl during the early stage of the discharge, in the low lithium concentration range in the FeOCl solid matrix (LixFeOCl, x<0.6). Such compounds are stable. However, at higher concentrations of lithium, FeOCl co-intercalated by lithium and solvent gradually decompose to yield α-Fe and other compounds. The results show that three electrons are consumed during the discharge. On the other hand, the discharge curve of FeOCl in propylene carbonate containing 1.0 M LiBF4 indicates only a single charge transfer step. Therefore, the reaction mechanism of FeOCl can be explained by the intercalation of lithium in FeOCl followed by the decomposition of the intercalation compound formed between FeOCl, lithium and the solvent. The structure of FeOCl intercalated by lithium changes during the course of immersion in various solvents. This fact indicates that the solvent can easily intercalate into FeOCl and deintercalate from FeOCl. Such a behavior may arise from a weakening of the interaction between FeOCl layers after lithium intercalation, since the intercalation of lithium into FeOCl influences the chemical bonds in FeOCl. As a result, the interaction between FeOCl layers becomes weaker. Therefore, the intercalation and deintercalation of the solvent can easily take place. The stability of the FeOCl structure after cathodic reduction does not depend only on the concentration of lithium in FeOCl, but also on the kind of solvent.