bluuebunny/crossref_metadata_2025_split huggingface dataset:
Structure of Cobalt(III) Complexes with (R,R)- and (R,S)-N,N,N′,N′-Tetrakis(2-aminoethyl)-2,4-pentanediamine and N,N,N′,N′-Tetrakis(2-aminoethyl)-1,3-propanediamine
Authors: Ishii Toshio , Ohba Shigeru , Ito Masatoki , Fukushi Sachio , Saito Yoshihiko 
Published: July 2006

Abstract
Crystal structures of the two isomeric Co(III) complexes with sexidentate ligands, (NH2CH2CH2)2NC*H(CH3)CH2C*H(CH3)N(CH2CH2NH2)2 (hereafter abbreviated as R,R- and R,S-tptn) and of the Co(III) complex with a sexidentate ligand, (NH2CH2CH2)2NCH2CH2CH2N(CH2CH2NH2)2 (abbreviated as ttn) were determined by an X-ray diffraction method. The crystal data and the final R factors are: (1) [Co(R,R-tptn)](ClO4)3·H2O, tetragonal, P42212, a=12.800(1), c=15.312(1) Å, V=2509(1) Å3, Z=4, R=0.053 for 1627 observed unique reflections, (2) [Co(R,S-tptn)]Cl3·3H2O, monoclinic, P21⁄a, a=16.778(6), b=14.296(2), c=9.478(4) Å, β=110.99(3)°, V=2123(1) Å3, Z=4, R=0.045 for 3583 reflections and (3) [Co(ttn)]Br3·H2O, trigonal, P\={3}cl, a=14.436(4), c=15.718(9) Å, V=2837(2) Å3, Z=6, R=0.096 for 1183 reflections. The equatorial preference of the methyl groups in the central six-membered chelate ring formed by Co and 2,4-pentanediamine moiety of R,R- and R,S-tptn has been recognized. In (1) the six-membered chelate ring adopts a twist boat form as in (3) with the two C–CH3 bonds in equatorial positions. In (2) the six-membered chelate ring takes a largely flattened chair form with the two C–CH3 bonds again in equatorial positions. The effect of an elongation of the Co–N bond distance on the energy of the first absorption band was discussed.
The Selective N-Monoalkylation of Amides with Alkyl Halides in the Presence of Alumina and KOH
Authors: Sukata Kazuaki 
Published: July 2006

Abstract
The effects of alumina impregnated with KOH (KOH/Al2O3) and a mixture of alumina and powdered KOH (KOH+Al2O3) have been examined using the alkylation of benzamide under various conditions. In each case, alkylation occurs exclusively in the pores of the alumina, the extent depending upon the alumina-pore size. For both yield and selectivity for N-monoalkylation, KOH+Al2O3 is superior to KOH/Al2O3. Dioxane is the best of the solvents employed. It is proposed that, in dioxane, an enolate-like species, (Remark: Graphics omitted.), exists as stable ion-pair aggregates, which are the true reactants in the pore. This method, using KOH/Al2O3 or KOH+Al2O3, has been applied to N-alkylation of the other amides, giving the N-monoalkylated products in substantial yields with extremely high selectivities. 2-Phenylacetamide is regioselectively N-monoalkylated in high yields. This regioselectivity is explained in terms of steric hindrance.
Digital Derivative Spectrophotometric Determination of Micro Amounts of Iron with 1,10-Phenanthroline
Authors: Katsuyama Tetsuo , Shida Junichi 
Published: July 2006

Abstract
Digital first-order derivative spectrophotometry was applied to the determination of iron with 1,10-phenanthroline. Under the recommended conditions, a linear relationship was confirmed between the first-derivative value and the iron concentration. The present method gives accurate results for iron, ranging from 1.6×10−7 to 8×10−5 mol dm−3 (8.9 μg dm−3–4.5 mg dm−3). The relative standard deviations for the determination of 4.8×10−5, 4.8×10−6, and 4.8×10−7mol dm−3 of iron(III) were 0.37, 0.38, and 0.93%, respectively. The effects of 63 diverse ions were examined. The present method was applied to the determination of iron in practical samples, i.e., river water, waste water and sea water.
The Synthesis and X-Ray Structure of (l- or d-Alanine-N-acetato)(l-histidinato)chromium(III)
Authors: Sato Mitsunobu , Kosaka Masao , Watabe Masatoshi 
Published: July 2006

Abstract
The (l-alanine-N-acetato)(l-histidinato)chromium(III) monohydrate complex, C11H14N4O6Cr, has been synthesized and its crystal structure has been determined from three dimensional X-ray-diffractometer data. The crystals are orthorhombic, of the space group P212121, with 4 molecules in a cell with these dimensions: a=11.052(1), b=13.959(3), and c=9.616(2) Å. Block-diagonal least-squares refinements using 1318 independent nonzero reflections have yielded a conventional R factor of 0.033. The structure consists of monomeric [Cr(l-alama)(l-his)] units and water molecules. The l-alama ligand coordinates to the metal as of dianion, with Cr–O(acetyl), Cr–N, and Cr–O(alanine) bond lengths of 1.960(3), 2.078(5), and 1.946(4) Å respectively. The histidinate monoanion coordinates through Cr–N(amino), Cr–N(imidazole), and Cr–O bonds 2.062(4), 2.036(5), and 1.957(4) Å long respectively. The geometry at chromium is a distorted octahedron, with cis bond angles in the range from 80.1(2) to 99.3(2)°. Among the six possible isomers of the [Cr(l-alama)(l-his)] complex, only one isomer was prepared and crystallized; its geometry was r-l-trans(O)cis(N).
Solvent Extraction of Mercury(II) from Hydrochloric Acid with 1,2-Bis(hexylthio)ethane
Authors: Baba Yoshinari , Ikeda Yutaka , Inoue Katsutoshi 
Published: July 2006

Abstract
Solvent extraction of mercury(II) from hydrochloric acid with 1,2-bis(hexylthio)ethane (=BHTE=\barS) in 1,2-dichloroethane has been studied at 30 °C. Mercury(II) was found to be extracted into pure 1,2-dichloroethane without extractants, which is due to the physical partition of the neutral species, HgCl2. The partition coefficient, KD, was evaluated as KD=0.314. It was clarified that the extraction mechanism with BHTE can be explained in terms of solvation by BHTE and that 1:1 metal: the ligand complex is formed in the organic phase as follows.
\barS+HgCl2\ightleftharpoons‾HgCl2·S  Ke
The extraction equilibrium constant, Ke, was evaluated as Ke=1.61×103 dm3 mol−1.
The Short Range Structure of Ion-polar Solvent Mixtures. Calculations by the RISM Integral Equations
Authors: Ohba Masaharu , Arakawa Kiyoshi 
Published: July 2006

Abstract
The reference hypernetted chain like integral equation of the interaction site model is solved numerically for a solution of ions in a polar solvent. In our model, the ions and the solvent molecules are taken to be charged hard spheres and polar hard dumb-bells, respectively. Calculated pair correlation functions contain a great deal of interesting information on the short range structure of the ionic solutions: a solvated structure around ions and an effect of ionic charges upon the structure of the solvent. It is found that various types of associated structures of constituent species, such as simple ion pairs, ion triplets, and ion pairs separated by one solvent molecule exist in ionic solutions.
Catalytic Activity of Copper(II) Salt of Heteropolyphosphoric Acid for the Reduction of NO with Its Supporting Active Carbon
Authors: Mochida Isao , Yata Kiyoshi , Fujitsu Hiroshi , Komatsubara Yoshinobu 
Published: July 2006

Abstract
The catalytic activity of a copper(II) salt of polymolybdophosphoric acid (Cu1.1H0.8PA) for the reduction of NO with the supporting active carbon into N2 and N2O was studied at 400 °C using a fixed bed flow reactor. A considerable activity was observable at a stationary state where the spill-over of oxygen left on the active site of the acid to the carbon surface appeared to be rate-determining. The activity of the salt was much higher than for component oxides produced through its decomposition at higher temperatures. This suggested that the active site was characteristic to the salt (very probably the reduced site in the salt). The reaction mechanism in terms of the reaction paths, the N2O/N2 selectivity, and the roles of the supporting active carbon are discussed based on kinetic investigations.
Identification of the Adsorbate Formed on a Platinum Electrode from Methanol
Authors: Matsui Hiroshi , Hisano Takeo , Terazawa Toshio 
Published: July 2006

Abstract
The kind of carbon-containing adsorbate formed on a platinum electrode from methanol in an acid medium was identified by an electrochemical method. Certain improvements were made in view of the harmful effects of the following factors on the QF value, the quantity of electricity required to form adsorbate. The factors: a) The amounts of dissolved oxygen in both solution and electrode itself; b) the concurrent oxidation of the adsorbate in the adsorption process; and c) the presence of by-products of the methanol oxidation, formaldehyde and formic acid. By appropriate procedures, these effects could be minimized or corrected. The ratio QF⁄Qox, where Qox was an electric quantity required to oxidize completely that amount of adsorbate corresponding to the QF, was found to be 1.8–2.0 when the potential was 0.30–0.54 V, and the methanol concentration 0.005–1 mol dm−3. It was thus concluded that the adsorbate was almost exclusively COad.
A Relation between Oxidation State of Sulfur and Acidic Property of Iron Oxide Containing Sulfur
Authors: Nagase Yoshinori , Jin Tuo , Hattori Hideshi , Yamaguchi Tsutomu , Tanabe Kozo 
Published: July 2006

Abstract
Five kinds of iron oxide catalysts promoted with sulfur were prepared by impregnating Fe(OH)3 with (NH4)2SO4 and by treating Fe2O3 and Fe(OH)3 with H2S and SO2. Changes in acidic properties of the catalysts with changes in oxidation states of sulfur were investigated by test reactions such as isomerization of cyclopropane and dehydration of 2-propanol over the oxidized or reduced catalysts. It has been found that the generation of acidic properties of the catalysts was independent of the kinds of the starting sulfur compounds, but dependent on the oxidation states of the sulfur. The sulfur in the highest oxidation state was responsible for the strongly acidic property of the catalyst.
Studies on Salt Hydrates for Latent Heat Storage. VII. The Relation between Activation Process of Crystal Nucleation Catalysts for Sodium Acetate Trihydrate and Their Deactivation Temperatures
Authors: Wada Takahiro , Yoneno Hiroshi 
Published: July 2006

Abstract
Influences of preheating temperature were studied on crystallization of CH3CO2Na·3H2O from its melts containing a small amount of Na4P2O7 or Na2HPO4 as a crystal nucleation catalyst. The relation between the activation process of these nucleation catalysts and their deactivation temperatures was investigated in detail. Aging of nucleation catalyst which was preceded by forced crystallization of CH3CO2Na·3H2O from its melt containing the catalyst, largely affects the catalyst’s deactivation temperature. Whenever Na4P2O7 or Na2HPO4 was used as a nucleation catalyst, the deactivation temperature was raised by lengthening aging time at a constant aging temperature. When the catalysts were aged for 4 d at 20 °C, the aging effect on them was almost saturated. At lower temperatures, longer aging times were required for saturation of the effect. The results obtained are discussed with a modified adsorption model, which takes into account commensurate-incommensurate phase transition of solid adsorbate.
Resonance Raman and 129I Mössbauer Spectroscopic Study of Iodine Doped in Poly(thienylene)s
Authors: Sakai Hiroshi , Mizota Manabu , Maeda Yutaka , Yamamoto Takakazu , Yamamoto Akio 
Published: July 2006

Abstract
Resonance Raman and 129I Mössbauer spectroscopy have been used in a study of iodine doped poly(thienylene)s, which are chemically synthesized by the polymerization of dibromothiophenes. It is shown that the iodine species in the polymers are present predominantly in the form of a polyiodide which consists of unsymmetrical I3− and I2 units. That is, the iodine molecule doped is reduced by taking electrons from the polymer in a similar manner to iodine doped in polyacetylene. This result is consistent with the fact that poly(thienylene)s undergo an increase in electrical conductivity upon doping with iodine.
Solvation and Protonation of 1,10-Phenanthroline in Aqueous Dioxane Solutions
Authors: Ishiguro Shin-ichi , Wada Hideo , Ohtaki Hitoshi 
Published: July 2006

Abstract
Solvation and protonation of 1,10-phenanthroline (phen) have been studied by potentiometry and calorimetry in various aqueous dioxane solutions. Protonation reactions were studied in the mixtures (the dioxane content x=0–0.4 mole fraction) containing 0.3 mol dm−3 NaCl as a constant ionic medium at 25 °C. Potentiometric and calorimetric titration curves obtained in the range of −log[H+]=2–7 were well explained in terms of the formation of Hphen+ and H(phen)2+, and the formation constants, enthalpies and entropies of formation of the species were determined. The formation constants of the both species gradually decreased with increasing x, and then the formation of H(phen)2+ became negligibly small at x&gt;0.1, while the enthalpy and entropy of formation of Hphen+ first decreased and then increased with increasing x and thus minima were found at x=0.05. Enthalpies of solution of anhydrous 1,10-phenanthroline were also determined in both neutral (x=0–1) and acidic (0.1 mol dm−3 HCl, x=0–0.4) aqueous dioxane solutions. By knowing enthalpies of solution of 1,10-phenanthroline in acidic solutions and of formation of Hphen+ in the mixed solvents, enthalpies of solution of 1,10-phenanthroline in neutral solutions (ΔH°s(phen)) were evaluated and compared with those directly obtained in the neutral solutions (ΔH°s,neutral). A significant difference was found between ΔH°s(phen) and ΔH°s,neutral in the range x&lt;0.3, which could be ascribed to the formation of stacked species of 1,10-phenanthroline molecules, (phen)n. The variation of ΔH°s(phen) with x was explained in terms of the enhanced solvation of dioxane to phenanthroline molecules owing to breaking of the hydrophobic water structure around them. Solvent effects on the formation of Hphen+ and H(phen)2+ were discussed in terms of different solvation behavior of 1,10-phenanthroline and proton with x.
Oxygen-17 NMR Study of the Uranyl Ion. II. Correlation between 17O NMR Chemical Shifts and Wavelengths of UV-Visible Absorption Bands of Uranyl Complexes
Authors: Jung Woo-Sik , Tomiyasu Hiroshi , Fukutomi Hiroshi 
Published: July 2006

Abstract
17O NMR chemical shifts, UV-visible and IR spectra of a series of [UO2Ln](ClO4)2 (L=unidentate oxygen-donor ligand; n=coordination number) complexes in nonaqueous solvents have been measured. The electronic transition bands of the UO22+ entity shift toward lower energies with the increase in base strength of ligands in the equatorial plane. The asymmetric stretching frequencies of U=O bands are also affected by the base strength of equatorial ligands and correlated with the lowest electronic transition energies of uranyl complexes with the same geometry. The 17O chemical shifts are shown to be related to the lowest electronic transition energies of uranyl complexes. It appears that oxygen isotope shifts in 17O NMR spectra of the uranyl ion are predominantly attributed to the increase in the lowest electronic transition energies.
Phase Equilibria in the Ln2O3–V2O3–V2O5 (Ln=Pr, Tb, and Y) Systems at 1200 °C
Authors: Kitayama Kenzo , Katsura Takashi 
Published: July 2006

Abstract
The phase equilibria in the systems, Pr2O3–V2O3–V2O5, Tb2O3–V2O3–V2O5, and Y2O3–V2O3–V2O5, were established at 1200 °C by changing the oxygen partial pressure from −1.20 (in the CO2) to 7.50 in −log (PO2/Pa) for Pr2O3 and Tb2O3 systems, and from −4.32 (in the air) to 7.50 in −log (PO2/Pa) for Y2O3 system. In the first system 0.81Pr2O3·0.19V2O5(A) and 3Pr2O3·V2O5(B), in the second 0.81Tb2O3·0.19V2O5(A′), and in the last one 4Y2O3·V2O5(A″) were stable in addition to Ln2O3, LnVO4, LnVO3, VnO2n−1 (n=2–7, and Ln means Pr, Tb, and Y), and VO2 under the present experimental conditions. On the basis of the established phase diagrams, the standard Gibbs energies (ΔG°) of reactions appeared in the systems were calculated. Compounds A, B, PrVO3, A′, A″, and LnVO4 have nonstoichiometric compositions. ΔG° values for the reactions and crystallographic values of the compounds were represented as a function of the ionic radius of lanthanoid (including Y) elements.
Electrocatalytic Oxidation of Chlorpromazine in Phosphate Solution
Authors: Takamura Kiyoko , Inoue Satoshi , Kusu Fumiyo , Oyama Noboru 
Published: July 2006

Abstract
The kinetics of electrocatalytic oxidation process of chlorpromazine (CPZ) at a pyrolytic graphite electrode in a phosphate solution was investigated by rotating disk voltammetry. The reactions involving regeneration process of CPZ through the disproportionation of reaction intermediates are proposed and the rate constants of the chemical reaction (kobsd), following the electrochemical oxidation of CPZ to the CPZ cation radical, were evaluated from the electrode rotation-rate dependence of the limiting currents obtained in the CPZ solution with and without phosphate. The proportional relations between the logarithm of kobsd and pH, and between kobsd and the concentration of H2PO4− were obtained.
Calorimetric and Raman Spectroscopic Studies on Formation of Cadmium(II) Thiocyanato Complexes in Aqueous Solution
Authors: Ishiguro Shin-ichi , Yamamoto Kiyoshi , Ohtaki Hitoshi 
Published: July 2006

Abstract
Complex formation equilibria between cadmium(II) and thiocyanate ions have been calorimetrically studied at 25 °C in aqueous solution containing NaClO4 in order to keep 3 mol dm−3 ionic strength in the test solutions. Calorimetric titration curves thus obtained were well explained in terms of formation of dinuclear [Cd2X]3+ (X=SCN) and mononuclear [CdXn](2−n)+ (n=1–4) complexes, and their formation constants, enthalpies and entropies were determined. The stepwise enthalpy and entropy values at the third consecutive step were largely positive, indicating that water molecules solvating Cd(II) ion were extensivelyl liberated at this step. It was thus suggested that the coordination symmetry around Cd(II) ion changed from octahedral to tetrahedral at the formation of [CdX3]−. Raman spectra of the C–S and C–N stretching vibrations of SCN− ion were measured in cadmium(II) thiocyanate solutions with varying molar ratios of the metal to ligand ions. It was shown that SCN− ion coordinated to Cd(II) ion through the N atom at the first step of the complex formation, and the S atom at the second, N at the third and then S at the last. The suggested bonding type of SCN− ion with Cd(II) ion within each cadmium(II) thiocyanato complex was supported by the thermodynamic data.
Synthesis of Aspartyl Pentapeptide Esters in Relation to Structural Features of Sweet Peptides
Authors: Ariyoshi Yasuo 
Published: July 2006

Abstract
A series of seven analogues of aspartyl pentapeptides has been synthesized in relation to the structural features of sweet peptides. The rule in the structure-taste relationships of di-, tri-, and tetrapeptides is inapplicable to the pentapeptides. All the pentapeptides were devoid of sweetness, though they satisfied the requirements for sweet peptides. The result indicates that oligopeptides can not fit a deep receptor pocket. The mode of interactions between sweet peptides and the receptor is drawn schematically.
Synthesis and Characterization of Macrocyclic Polyaza(2,5)pyridinophanes Possessing Vitamin B6 Functionality
Authors: Iwata Masaaki , Kuzuhara Hiroyoshi 
Published: July 2006

Abstract
Series of macrocyclic polyaza[m](2,5)pyridinophanes (poly=tri, tetra, penta; m=9, 12, 15)(8–10) and polyaza[m]paracyclophanes (11–13) were synthesized in excellent yields by the reaction of dichloropyridoxine derivatives (4) and α,α′-dibromo-p-xylene (5), respectively, with a series of 1,2-ethanediamine derivatives (1–3). These phanes were characterized on the basis of 1H NMR spectra. The methyl group at C6 of the pyridoxine moiety (a-series) revealed restricted rotation for all bridge sizes (m=9–15). In 8–10 without the methyl group (b-series), m=12 was the boundary between restricted and free rotation. In series 11–13, only 11 (m=9) showed restricted rotation. Atomic group equivalence was discussed in terms of boundary restricted rotation and an empirical rule for the prediction of the relationship between the bridge size and restricted rotation was proposed.
An Electric-Field-Pulse Relaxation Study of the Electron-Donor-Acceptor Complex Formation Involving 7,7,8,8-Tetracyanoquinodimethane Solubilized at the Surfactant Bilayer/Magnetite Particle Interface
Authors: Ikeda Tetsuya , Harada Shoji , Yasunaga Tatsuya 
Published: July 2006

Abstract
Ultrafine magnetite particle (Fe3O4) which adsorbed the 7,7,8,8-tetracyanoquinodimethane (TCNQ)dioctadecyldimethylammonium bromide (DODAB) bilayer on the surface were prepared in an aqueous solution by sonication. A single relaxation was found by using the electric-field-pulse method and was attributed to the association-dissociation process of the electron-donor-acceptor complexes involving TCNQ solubilized at the DODAB bilayer/magnetite particle interface.
Molecular Motion in GeCl4 as Studied by 35Cl Nuclear Quadrupole Resonance
Authors: Nakayama Hirokazu , Nakamura Nobuo , Chihara Hideaki 
Published: July 2006

Abstract
Temperature dependence of 35Cl nuclear quadrupole resonance frequencies and quadrupole relaxation time was measured of GeCl4 in the metastable phase. Above 160 K, molecular reorientation is seen active; its activation energy is 63.5 kJ mol−1. This energy probably prevents GeCl4 from undergoing a rotational phase transition.
Molecular Complexes of N,N,N′,N′-Tetraisopropyloxamide. Crystal Structures of Its 1:1 Adduct with m-Cresol, and Its 1:1 and 1:2 Adducts with p-Cresol
Authors: Toda Fumio , Tagami Yasunori , Mak Thomas C W 
Published: July 2006

Abstract
The crystal structures of a 1:1 complex (I) of N,N,N′,N′-tetraisopropyloxamide with m-cresol, a 1:1 complex (II) with p-cresol, and a 1:2 complex (III) with p-cresol have been determined by X-ray crystallography. The crystal data are: I, C21H36N2O3, P21⁄c, a=12.104(4), b=6.860(3) c=27.186(8) Å, β=93.46(2)°, Z=4, and RF=0.093 for 1661 observed Mo Kα data; II, C21H36N2O3, P21⁄n, a=7.825(2), b=11.379(4), c=25.39(1) Å, β=91.01(2)°, Z=4, and RF=0.105 for 1326 data; III, C28H44N2O4, C2⁄c, a=11.744(3), b=10.658(2), c=23.576(4) Å, β=102.07(2)°, Z=4, RF=0.045 for 1382 data. The stoichiometric formulas faithfully represent the structures of all three complexes, with each phenolic OH group forming a donor hydrogen bond to an O atom of the oxamide host molecule.
Photochemical Hydroxymethylation of Alicyclic and Aliphatic Alkenes Induced by a EuIII/EuII Photoredox System in Methanol
Authors: Ishida Akito , Yamashita Shinya , Toki Susumu , Takamuku Setsuo 
Published: July 2006

Abstract
The photoirradiation of a methanol solution of EuCl3 and alkenes such as cyclohexene, cyclooctene, cyclododecene, and tetramethylethylene afforded (hydroxymethyl) alkane. The dihydro dimer of alkene, hydrogen, and ethylene glycol are also formed. Reactions proceed via a radical mechanism induced by hydrogen atoms and hydroxymethyl radicals, which are produced by a photoredox reaction of EuIII/EuII in methanol.
Syntheses of Cyclic Decapeptides with Four Ornithyl Residues Related to Gramicidin S
Authors: Ando Setsuko , Nishikawa Hiroshi , Takiguchi Hideo , Izumiya Nobuo 
Published: July 2006

Abstract
Three cyclic decapeptides with four l-ornithyl residues related to gramicidin S (GS), cyclo(–Orn–Leu–Orn–d-Phe–Pro–)2 (D-L-12), cyclo(–Orn–Leu–Orn–Phe–Pro–)2 (L-L-12), and cyclo(–Orn–Leu–Orn–Phe–d-Pro–)2 (L-D-12), were synthesized to investigate the contribution of increase of the basic amino acid residues and of configurations of phenylalanyl and prolyl residues toward antibacterial activity. These GS-like analogs were synthesized by the solution method of peptide synthesis. Protected cyclic decapeptides were synthesized through a cyclization reaction of linear decapeptide azide in pyridine. Hydrogenolysis of the protected cyclic decapeptides afforded crystalline tetrahydrochlorides of the desired analogs. In the experiment of circular dichroism, D-L-12 gave a curve similar to that of GS, while L-L-12 and L-D-12 gave different curves. Antibacterial assays showed L-L-12 exhibited substantial activities against Gram-negative bacteria, whereas D-L-12 and L-D-12 negligible activity.