bluuebunny/crossref_metadata_2025_split huggingface dataset:
Stoichiometries and Equilibrium Constants of Cyclodextrin-Surfactant Complexations
Authors: Funasaki Noriaki , Yodo Hiromi , Hada Sakae , Neya Saburo 
Published: July 2006

Abstract
General and rigorous theory for equilibrium concentrations of uncomplexed species and 1 : 1, 1 : 2, 2 : 1, and 2 : 2 complexes of cyclodextrin (D) and surfactant has been developed and applied to evaluate the binding constants of these complexations from surface tension data of aqueous solutions of dodecyl maltoside (DM) with α-, β-, and γ-D, reported by Saeger and Muller-Fahrnow. The orders of the binding constants for 1 : 1 and 2 : 1 complexations of D and DM are α-D &gt; β-D &gt; γ-D. Those for 1 : 2 and 2 : 2 complexations are γ-D &gt; β-D &gt; α-D. These orders are explained on the basis of the goodness of fit of the dodecyl chain into the cyclodextrin cavity. Furthermore, the theory for the effects of D on the molar conductivity and the critical micelle concentration (cmc) of an ionic surfactant is modified by accounting for the change of these values with the surfactant concentration and applied to evaluate the binding constants for 1 : 1, 1 : 2, and 2 : 1 complexations of sodium dodecyl sulfate (SDS) and β-D from conductance and cmc data reported by Palepu and Reinsborough. Although there are several uncertainties in experimental data and their interpretations for the β-D-SDS system, the 1 : 1 complexation is predominant and its binding constant appears to be 5000 dm3 mol−1. Based on the present analysis, it is suggested that since a surfactant is a long and fine molecule, relative to aromatic compounds, its ternary and quaternary complexes with D’s as well as its binary complex should be taken into consideration.
Rate Constants of the Photodegradation and Photoisomerization of Polyenes Produced in Heat-Treated PVA Film
Authors: Maruyama Kazunori , Kuramoto Yasunori , Tanizaki Yoshié , Kobayashi Michio , Kuchitsu Kozo 
Published: July 2006

Abstract
The rate constants of two parallel reactions, photodegradation and photoisomerization of polyenes,n with n = 2–5, produced in heat-treated PVA film are estimated by an analysis of the spectral changes on monochromatic irradiation (200–250 nm). The rate constants for isomerization is found to be ten times as large as that of degradation.H=CH
The Kinetic Study of the Oxygen-Exchange Reaction of Some Alkylarsonates and Dialkylarsinates with Water
Authors: Okumura Akiko , Fushimi Midori , Hanaki Hiroko , Yamada Akiko , Gofuku Youko , Kagawa Mika , Niwa Nobuko , Yamamoto Masako , Iida Masayasu 
Published: July 2006

Abstract
The rates (RS) of the oxygen exchange reaction of alkylarsonates (methyl-, butyl-, hexyl-, and benzyl-) and dialkylarsinates (dimethyl- and dibutyl-) with solvent water were measured in the pH range greater than 6, and at temperatures between 30 and 0 °C. For arsonates, the rate (R) is expressed by the following rate law: R = k1[A2−] + k2[HA−] + k3[H2A] + k4[HA−]2 + k5[HA−][H2A] + k6[H2A]2, where A2−, HA−, and H2A designate R′AsO32−, R′AsO3H−, and R′AsO3H2 (R′ = alkyl), respectively. For arsinates, R = k1[R′2AsO2−] + k2[R′AsO2H] (pH &gt; 9). The exchange rates of arsonates at 0 and 30 °C were analyzed in terms of the rate law to obtain the values of the rate constants (k1–k6). The activation parameters were obtained for the k1 paths of both arsonates and arsinates, which are the reaction between R′AsO32− or R′2AsO2− and water. It is noticeable that the values of the activation entropies of the arsonates were found to be negative, while those of the arsinate were found to be positive. It was suggested that the oxygen exchange of arsonate ions proceeds via an SN2 mechanism, while that of arsinates preceeds via SN1.
183W NMR and X-Ray Crystallographic Studies on the Peroxo Complexes of the Ti-Substituted α-Keggin Typed Tungstophosphates
Authors: Yamase Toshihiro , Ozeki Tomoji , Motomura Shigeyuki 
Published: July 2006

Abstract
Peroxo complexes prepared by the reaction of titanoundecatungstophosphate (PTiW11O405−) and dititanodecatungstophosphate (PTi2W10O407−) with hydrogen peroxide are characterized by means of the 183W NMR spectroscopy and the single crystal X-ray diffractometry. Electronic spectra and permanganate titration analyses indicated that one peroxo ligand attaches to the PTiW11O405− anion and two peroxo ligands attach to the PTi2W10O407− anion. 183W NMR spectra showed that the Cs symmetry of the PTiW11O405− anion and the C2 symmetry of the PTi2W10O407− anion are retained in the respective peroxo derivatives. Single crystal X-ray structures of the diisopropyl ammonium salt of PTiW11O405−, the diisopropyl ammonium salt of PTiW11O39(O2)5− and the isopropyl ammonium salt of PTi2W10O38(O2)27− indicated that the peroxo anions retain the α-Keggin structures of their parent anions. It was inferred that the peroxo ligands are substituted for the terminal oxygen atom at the TiO6 octahedra with the side-on format.
Structural and Conducting Properties of (TTF)(DMeT-DCNQI)
Authors: Mori Takehiko , Inokuchi Hiroo 
Published: July 2006

Abstract
The title charge-transfer complex, where TTF is tetrathiafulvalene, and DMeT-DCNQI is 2,5-bis(methylthio)-p-benzoquinone bis(N-cyanoimine), crystallizes in triclinic space group , a = 15.447 (3), b = 15.774 (3), c = 3.834 (2) Å, α = 96.96 (3), β = 97.14 (3), γ = 82.24 (2)°, V = 913 (5) Å3 and Z = 2. The donor and acceptor molecules form segregated colums. This complex shows high electrical conductivity, 400 S cm−1 at room temperature, and undergoes a metal-semiconductor transition at around 130 K.
The Fluorescence Properties of (2-Nitro-5,10,15,20- tetraphenylporphyrinato)zinc
Authors: Takahashi Kohshin , Hase Shino , Komura Teruhisa , Imanaga Hiroto , Ohno Osamu 
Published: July 2006

Abstract
The photophysical and redox properties of (2-substituted porphyrinato)zinc derivatives in various solvents are investigated. Zinc complexes of 2-bromo-, 2-cyano-, and 2,3-(l,4-phenylenedinitrilo)-substituted porphyrins as well as (tetraphenylporphyrinato)zinc (Zntpp(H,H)) exhibit well-resolved Q0,0 and Q0,1 fluorescence peaks, while (2-nitro-substituted porphyrinato)zincs emit a red-shifted fluorescence with a less resolved vibrational fine structure. Stokes shift of (2-nitro-5,10,15,20-tetraphenylporphyrinato)zinc (Zntpp(H,NO2)) is considerably larger than that of Zntpp(H,H), and increases with the increase in the dielectric constant of aprotic solvents. The results are ascribed to the intramolecular charge transfer from the porphyrin ring to 2-nitro group in the lowest singlet excited state of Zntpp(H,NO2).
Determination of Arsenic(III) and Arsenic(V) by Hydride Generation– Atomic Absorption Spectrometry Following a Rapid Coprecipitation Technique with Hafnium(IV) Hydroxide
Authors: Ueda Joichi , Kagaya Shigehiro 
Published: July 2006

Abstract
Hafnium(IV) hydroxide quantitatively coprecipitates 10–120 ng of arsenic(III) and arsenic(V) from a 100– 300 cm3 sample solution at pH 6.0–10.5. After coprecipitation, arsenic(III) can be sensitively determined by heated quartz glass cell atomic absorption spectrometry utilizing arsine generation with sodium tetrahydroborate; arsenic(V) can also be determined in the same manner as above after reducing it to arsenic(III). Interference from hafnium(IV) in the determinations of arsenic (III) and arsenic (V) can be eliminated by using perchloric acid and potassium iodide, respectively. The calibration curves are linear from 0.5–6.0 ng cm−3 for both arsenic(III) and arsenic(V). Since this method can be used to determine arsenic(III) as well as the sum of the amounts of arsenic(III) and arsenic(V), it is possible to determine arsenic(III) and arsenic(V) consecutively.
Complex Formation of Poly(acrylic acid) with Mg, Mn, and Pb Ions in Dioxane-Water Mixed Solvents
Authors: Hayashi Hiromichi , Komatsu Tsuyoshi 
Published: July 2006

Abstract
Equilibria between poly(acrylic acid) and Mg(II), Mn(II) and Pb(II) ions have been investigated at 25 °C by means of potentiometric and viscometric titrations in dioxane-water mixed solvents containing 0.1 mol dm−3 added salt to maintain a constant ionic strength. The stability constant for the complex formation reaction, M2+ + iA− = MAi2−i, and the equilibrium constant for the reaction, M2+ + iHA = MAi2−i + nH+ (HA denotes a carboxyl group) have been evaluated from the data of pH titration. Although the stability constants, β1 and β2, increased with dioxane content in the mixed solvent and depended on the kinds of added salts, the equilibrium constants, B1 and B2, were almost independent of both factors. The values of B1 for Mg, Mn, and Pb monocarboxylate complexes were 10−3.1, 10−2.5, and 10−1.0 and those of B2 for Mg, Mn, and Pb dicarboxylate complexes were 10−7.6, 10−5.7 and 10−2.1, respectively. From the data of viscometric titrations of poly(acrylic acid) solutions containing Pb(II) ion, it is considered that the contraction of polymer coil is caused by the intramolecular complex formation with two remote carboxylate groups in the range of low degree of neutralization (α′). As α′ increases, the complex is transformed into another form which consists of two adjacent carboxylate groups.
Triethylborane Induced Radical Reaction of Ketene Silyl Acetals with Polyhalomethanes
Authors: Miura Katsukiyo , Sugimoto Jiro , Oshima Koichiro , Utimoto Kiitiro 
Published: July 2006

Abstract
The treatment of ketene silyl acetal with tetrahalomethane or trihalomethane at room temperature in the presence of a catalytic amount of Et3B provides 3,3-dihaloacrylate or (E)-3-haloacrylate, respectively. On the other hand, a reaction at −23 °C mainly gives 3,3,3-trihalopropanoate or 3,3-dihalopropanoate.
Mixing State of 1-Propanol Aqueous Solutions Studied by Small-Angle X-Ray Scattering: A New Parameter Reflecting the Shape of SAXS Curve
Authors: Hayashi Hisashi , Udagawa Yasuo 
Published: July 2006

Abstract
Small-Angle X-ray Scattering (SAXS) of 1-propanol aqueous solutions was measured at various temperatures with a newly constructed point-focusing diffractometer. Owing to the improvement of the SAXS data, it is now possible to accurately determine the higher order coefficients in a polynomial expansion. Accordingly, a new parameter which reflects the shape of the SAXS curve (χ) is proposed. The mixing states of 1-propanol aqueous solutions are discussed in terms of χ as well as the concentration fluctuation and correlation length which are also derived from SAXS measurements. Every obtained result implies that the mixing state of the solution changes very much above and below a concentration of about 15 mol%, and that the new parameter (χ) is very effective as an indicator.
Intramolecular Radical Cyclization of Ketene Dithioacetals
Authors: Yamamoto Makoto , Furusawa Atsuko , Iwasa Seiji , Kohmoto Shigeo , Yamada Kazutoshi 
Published: July 2006

Abstract
A novel intramolecular ketene radical cyclization was described. Treatment of α-bromo-β-alkoxycarbonyl- and α-bromo-β-oxoketene dithioacetals with tributyltin hydride and AIBN gave lactones and cyclic ketones bearing bis(methylthio)methylene substituent at α-position in moderate yields. Tandem radical cyclization of ketene radical synthons were also carried out.
Syntheses and Structures of Novel Ruthenium(II)-Chiral Diphosphine Complexes
Authors: Kawano Hiroyuki , Ikariya Takao , Ishii Youichi , Kodama Teruyuki , Saburi Masahiko , Yoshikawa Sadao , Uchida Yasuzo , Akutagawa Susumu 
Published: July 2006

Abstract
Novel ruthenium complexes coordinated with various chiral diphosphines were synthesized by reactions of polynuclear [RuCl2(cycloocta-1,5-diene)]n with the respective diphosphines in the presence of triethylamine. The compositions of the complexes thus obtained were varied according to the solvent used (toluene or ethanol). The structures and dynamic properties of the complexes bearing 2,2′-bis(diphenylphosphino)-1,1′-binaphthyl (binap) in solution were elucidated by the 1H and 31P{1H} NMR measurements. The X-ray diffraction analysis of trans-RuHCl((R)-binap)2 indicated that the conformation of seven-membered chelate rings and the edge-face manner of phenyl groups were almost the same as those of corresponding rhodium complexes.
Syntheses and Magnetic Properties of Imidazolate-Bridged Binuclear Copper(II) Complexes: Effect of Bridging Mode upon Magnetic Interaction
Authors: Ohkubo Sakurako , Inoue Keiji , Tamaki Hiroko , Ohba Masaaki , Matsumoto Naohide , Okawa Hisashi , Kida Sigeo 
Published: July 2006

Abstract
Three imidazolate-bridged binuclear copper(II) complexes [Cu(A)Cu(Ln)]ClO4, 1 (n = 1), 2 (n = 2), and 3 (n = 3), have been prepared and characterized, where H2A = 4-(6-methyl-8-hydroxy-2,5-diazanonane-1,5,7-trienyl)imidazole, HL1 = N-salicylidene-2-(2-pyridyl)ethylamine, HL2 = N-(1-methyl-3-oxobutylidene)-2-(2-pyridyl)ethylamine, and HL3 = 3,3′-(trimethylenedinitrilo)-bis[2-butanone oximate]. The cryo-magnetic susceptibility data (4.2–300 K) of 1 and 2 were well reproduced by the Bleaney–Bowers equation based on H = −2JSCu · SCu with the J values of −46.1 and −36.6 cm−1, respectively, while the magnetic data of 3 showed no magnetic interaction. The reference complexes [Cu(Ln)(py)]ClO4 (n = 1,2; py = pyridine) have been subjected to single-crystal X-ray diffraction analysis.
Cyclic Voltammetric Behavior and Some Surface Characteristics of the Lead Electrode in Aqueous NaI Solutions
Authors: El-Halim A Mohamed Abd , Fawzy Mohamed Hossam , El Rehim Sayed Sabet Abd , Saty Abd El Kader 
Published: July 2006

Abstract
Cyclic voltammograms of the quiescent lead electrode were examined in NaI solutions of various concentrations ranging between 0.03 and 1.30 M (1 M = 1 mol dm−3). Neither visual PbI2 surface layer nor a typical voltammogram could be obtained unless five complete cycles were preformed in advance. This behavior was not observed for the cyclic voltammetric behavior of the lead electrode in chloride and bromide solutions and consequently could be referred to the less aggressive nature of the I− ion in comparison to the former halide ions. The data proved that the formation of a passivating layer of PbI2 is a reversible process and depends primarily upon the concentration of NaI. By controlling the voltammetric conditions, particularly the number and mode of repeated cycles, thickening of the PbI2 surface layer could be feasible. Moreover, the microstructure of the PbI2 surface layer, as revealed by scanning electron microscopy, exhibited a simple correlation to the operating conditions. The obtained results pointed to the importance of the preceding complete cycles in building up of a relatively thick layer of spongy lead. Consequently, this layer is much more available for the formation of a thick, fine grained, and more compact PbI2 surface layer by a reasonable number of only anodic spans. Investigation of the anodic surface products by X-ray diffractometry proved that the layers are formed of PbI2 in the hexagonal crystalline structure and contamination by any other species could not be detected.
Extraction and Spectrophotometric Determination of Palladium with Pyridine-2-acetaldehyde Salicyloylhydrazone
Authors: Sinha Sunetra H , Sawant Arun D 
Published: July 2006

Abstract
A simple and rapid method is proposed for the separation by solvent extraction and spectrophotometric determination of palladiuim(II) with pyridine-2-acetaldehyde salicyloylhydrazone (PASH). The optimum conditions were evaluated by studying critically pH, reagent concentration, and period of equilibration. The palladiuim was determined by measuring Pd(II)–PASH extracted complex in chloroform at 425 nm. The proposed method offers excellent separation of Pd(II) from rutheniuim, cobalt, nickel, copper, and rhodium. The method was applied for the analysis of palladium catalyst and platinum ores.
Diphenyl (2,3-Dihydro-2-thioxo-3-benzoxazolyl)phosphonate: A New, Reactive Condensing Agent for the Synthesis of Amides, Esters, Peptides, and β-Lactams via Condensation
Authors: Ueda Mitsuru , Mori Hideharu 
Published: July 2006

Abstract
Diphenyl (2,3-dihydro-2-thioxo-3-benzoxazolyl)phosphonate (1) prepared from 2-benzoxazolethiol and diphenyl phosphorochloridate was proved to be a very useful condensing agent. A variety of amides, esters, and dipeptides were obtained in excellent yields. Furthermore, this reagent was successfully applied to the synthesis of β-lactams from β-amino acids.
Formation of Through-Ring α-Cyclodextrin Complexes with α,ω-Alkanedicarboxylate Anion.Effects of the Aliphatic Chain Length and Electrostatic Factors on the Complexation Behavior
Authors: Watanabe Midori , Nakamura Hiroshi , Matsuo Taku 
Published: July 2006

Abstract
α,ω-Alkanedicarboxylic acid anions with a long spacer methylene chain were observed to form dynamically and statically stable complexes with α-cyclodextrin (α-CD) at an NMR time scale in both neutral and basic media. The structures of these complexes were confirmed to be a “through-ring” type CD complex by measurements of the intermolecular NOESY and NOE difference spectra. From the thermodynamic data in basic media (pD 13), the dynamical stability of these type complexes were attributed not to the steric interaction, but to an electrostatic interaction between the dicarboxylate anion and ionized-CD.
Chiral 2-Cyanocinnamates in Conjugate Addition Asymmetric Enolate Trapping Reactions
Authors: Cativiela Carlos , Diaz-De-Villegas Maria Dolores , Galvez José Antonio 
Published: July 2006

Abstract
Chiral 2-cyanocinnamates react with l-selectride® to give an intermediate enolate which can be stereoselectively trapped with different halides to afford α-substituted phenylalanine precursors with excellent chemical yields and good diastereomeric excess.
Regioselective Allylations of Pyrimidine Ribonucleosides Using Pd(0) Catalyst
Authors: Kumar Vaijayanti , Gopalakrishnan Vidhya , Ganesh K Nagappa 
Published: July 2006

Abstract
A novel procedure for regiospecific O-allylation of pyrimidine ribonucleosides is reported by using Pd(PPh3)4–allyl ethyl carbonate reagent to synthesize 2′-O-allyluridine and 2′-O-allylcytidine. 3-N-allylation of the pyrimidine ring is prevented by protection of uridine imide function by 4-O-(2,5-dimethylphenyl) group which can be transformed to 4-oxo function of uridine or exocyclic amino function of cytidine.
Competitive Intramolecular Electron Transfer and SN2 Reactions of Radical Anions. Effects of Solvent Polarity on the Reaction Mechanism
Authors: Kimura Norio , Takamuku Setsuo 
Published: July 2006

Abstract
The solvent effects on the chemical reactivities of the radical anions of 1-(4-biphenylyl)-ω-chloroalkane have been investigated by using a pulse radiolysis technique. The reaction rates and reaction mechanism (intramolecular electron transfer and SN2) were found to change as a function of the polarity of the solvent used. On the basis of these results, it is discussed how their dichotomy takes place.
CO2 Laser Induced Sensitized Dissociation of Ethylene Oxide
Authors: Vatsa Rajesh Kumar , Kumar Awadhesh , Rao Kemmannu Annaji , Chowdhury Pradyot Kumar , Rama Rao Kuchimanchi Venkata Subba 
Published: July 2006

Abstract
Ethylene Oxide (C2H4O), when excited by energy transfer from SF6 using a pulsed CO2 laser, undergoes isomerization to CH3CHO followed by dissociation. The intermediate isomerized product, acetaldehyde, is formed with excess internal erergy sufficient to decompose into CH3 and CHO radicals. CH3 radicals could be trapped by their reaction with chlorine, forming CH3Cl as a stable product. Also, the intermediate acetaldehyde could be partially stabilized in the presence of argon. An average excitation energy of C2H4O molecule was found to be 65 kcal mol−1. Average number of photons absorbed per SF6 molecule, &lt;n&gt;, was calculated to be 13 from the direct measurement of absorbed energy. The product distribution indicates that radical chain mechanism does not play a significant role in the present laser induced reaction.
Tautomerization and Dissociation Equilibria of β-Diketones in Microemulsions
Authors: Watarai Hitoshi , Takano Mikako , Suzuki Nobuo 
Published: July 2006

Abstract
The keto–enol tautomerization and dissociation equilibria of benzoylacetone, benzoyltrifluoroacetone, and 2-naphthoyltrifluoroacetone were studied in anionic, cationic, and nonionic microemulsions by means of UV spectrophotometry. The enol fraction in the microemulsions, which increased with an increase of the volume fraction of the organic components, was explained by the distribution model of the β-diketones between the pseudo-phases. The apparent dissociation constants in the cationic microemulsions were larger than those in the anionic or nonionic microemulsions. This result is discussed based on the distribution of the enolate form into the interphase, which was significantly affected by the surface charge of the microemulsions.
Rotational Distribution of CO(b3Σ+) Produced in Energy Transfer Reaction from Ar(3P2) to CO
Authors: Tsuji Masaharu , Yamaguchi Kazuo , Kikukawa Mitsuo , Kouno Hiroyuki , Funatsu Tsuyoshi , Nishimura Yukio 
Published: July 2006

Abstract
The rotational energy disposal of CO(b3Σ+) in the Ar(3P2) + CO reactions has been measured by observing CO(b3Σ+–a3Πr) emission in an Ar flowing afterglow. The initial rotational distribution of CO(b : ν′ = 0,1) was expressed by a single Boltzmann temperature of 7000 ± 700 K. The fraction of available energy deposited into rotational mode of CO(b), &lt;fr&gt;, was estimated to be 32 ± 2%.
Dielectric Behavior of Aqueous Binary Mixtures of Hydrophobic Solutes
Authors: Prabhu Peesapati Venkata Seshadri Sekhar , Ramanamurti Medepalli Venkata 
Published: July 2006

Abstract
Dielectoric constant data for aqueous binary mixtures of ethylene glycol (EG), 2-methoxyethanol (ME), and 1,2-dimethoxyethane (DME) at different mole fractions and at various temperatures are reported. A decrease in dielectric constant values has been observed with the increase in solvent content of the mixture as well as the temperature in case of all the three systems. The variations in Kirkwood’s correlation factor (gK) with respect to the solvent composition in the three types of mixtures have been attributed to the short-range dipolar interactions which lead to structural changes in respective solvent mixtures.
Paper Chromatographic and 1H NMR Study of Ion Pair Interactions between N-Dodecanoylhistidine Methyl Ester and Dodecyl Dihydrogenphosphate in Chloroform
Authors: Verma Jyoti , Sahal Dinkar 
Published: July 2006

Abstract
A mixture of N-dodecanoylhistidine methyl ester (DHOMe) and dodecyl dihydrogenphosphate (DDP) gave a chromatographically distinct complex in chloroform, where the imidazole staining was markedly enhanced and the phosphate staining showed a characteristic delayed appearance. The 1H NMR chemical shift of 8.53 ppm (imidazole C–2H) observed for a 1 : 1 mixture of the two amphiphiles was downfield shifted by nearly 1.0 ppm vis-à-vis DHOMe alone. The data suggest that the complex between DHOMe and DDP in chloroform is stabilized by hydrogen bonding and ion-pair interactions.
Structures of Two Geometrical Isomers of Dioxo[(S)-N-salicylidene-3-aminopyrrolidine]vanadium(V)
Authors: Nakajima Kiyohiko , Tokida Nobuko , Kojima Masaaki , Fujita Junnosuke 
Published: July 2006

Abstract
The title complex was prepared and the crystal structure was determined by the X-ray method. Two geometrical isomers are involved in a unit cell. For each isomer, the coordination polyhedron is a distorted square pyramid, and the two isomers differ from each other with respect to the mutual disposition of the basal chelate ligand and the apical V=O group.
Catalytic Asymmetric Synthesis of Optically Active Secondary Alcohols Deuterated on the Secondary Carbon by the Enantioselective Alkylation of Aldehydes
Authors: Soai Kenso , Hirose Yuji , Sakata Shuichi 
Published: July 2006

Abstract
Optically active secondary alcohols deuterated on the secondary carbon were obtained in high enantiomeric excesses from the enantioselective addition of dialkylzincs to aldehyde–formyl-d’s using chiral catalysts.