bluuebunny/crossref_metadata_2025_split huggingface dataset:
Charge-Transfer Rates in Thin Polyelectrolyte Films Incorporating a Redox Molecule with Two Separate Electroactive Centers Having Different Redox Potentials. An Alizarine Red S–Cationic Perfluoropolymer Film System
Authors: Ohsaka Takeo , Takahira Youko , Hatozaki Osamu , Oyama Noboru 
Published: July 2006

Abstract
The diffusion coefficients for the charge-transport processes through 9,10-dihydro-3,4-dihydroxy-9,10-dioxo-2-anthracenesulfonate (Alizarine Red S, 1)-incorporating cationic perfluoropolymer (CPFP) polyelectrolyte films on electrodes undergoing oxidation or reduction of two separate electroactive centers with different redox potentials, i.e., the two-electron reduction of 1 to 3,4,9,10-tetrahydroxy-2-anthracenesulfonate (2) and the two-electron oxidations of 2 to 1 and 1 to 3,4,9,10-tetrahydro-3,4,9,10-tetraoxo-2-anthracenesulfonate ( 3) were measured by potential-step chronoamperometry and chronocoulometry. The apparent diffusion coefficients for 1 to 2, 2 to 1, and 1 to 3 processes where the first two processes are reversible and the 1 to 3 process is irreversible, represented as Dapprev(1→2), Dapprev(2→1) and Dappirrrev (1→3), respectively, decreased with increasing the concentration (Cfilm) of 1 (or 2) in the CPFP film, and for a given Cfilm they were found to be in the following order: Ds′&gt;&gt;Dapprev (1→2)∼Dapprev(2→1)&gt;Dappirrev (1→3), where Ds′ represents the diffusion coefficients corresponding to the diffusion of supporting electrolyte ions coupled to electron transfer and molecular motion of reactant itself. It became apparent that the difference in Dapprev(1→2) (or Dapprev(2→1)) and Dappirrev (1→3) can be attributed to different contributions of electron exchange between electroactive centers to the overall charge-transport rates. The results demonstrate that the contributions from molecular motion of reactant itself and electron exchange between reactants to the overall charge-transport rates can be estimated depending upon which redox center is employed in an electrochemical measurement of diffusional rates.
Physicochemical Properties of α,ω-Type Surfactant in Aqueous Solution. Bis(triethylammonium) 1,20-Eicosanediyl Disulfate
Authors: Ikeda Kenji , Ishikawa Motoharu , Yasuda Masaaki , Esumi Kunio , Meguro Kenjiro , Binana-Limbele William , Zana Raoul 
Published: July 2006

Abstract
The physicochemical properties of the α,ω-type (bolaform) surfactant, bis(triethylammonium) 1,20-eicosanediyl disulfate (α,ω C20N2Et6), in aqueous solution have been investigated by means of surface tension, electrical conductivity, dye solubilization and time-resolved fluorescence quenching. The critical micelle concentration of α,ω C20N2Et6 was 1–1.3×10−3 mol dm−3. The micelle ionization degree of the surfactant was larger than a conventional surfactant having the same head group. From surface tension measurements, the molecular area of α,ω C20N2Et6 at the air–water interface was found to be about twice as large as that of a normal type surfactant, such as sodium dodecyl sulfate (SDS). This reveals that α,ω C20N2Et6 probably forms vertical looping (“wicket-like” conformation) at the air–water interface. By time-resolved fluorescence quenching measurements, the aggregation number of α,ω C20N2Et6 micelle was found to be strongly dependent on the concentration, but only slightly dependent on the temperature. At low concentrations the aggregation number is close to half that corresponding to a normal type surfactant having a chain length that is that of the bolaform. The solubilizing power of a micellar solution of α,ω C20N2Et6 toward Orange OT was 7.6×10−3 mol of dye per mol of surfactant, that is, a value smaller than that of SDS.
Inversion and Deuteration at the Chiral Nitrogen Centers of [Co(acac or ox)2(Me-en or Me3en)]+or− (acac=2,4-Pentanedionate Ion; ox=Oxalate Ion; Me-en=N-Methylethylenediamine, Me3en=N,N,N′-Trimethylethylenediamine)
Authors: Ma Guilin , Hibino Tomomi , Kojima Masaaki , Fujita Junnosuke 
Published: July 2006

Abstract
The rates of the base-catalyzed proton exchange (deuteration, kD) and isomerization (epimerization, kep) at the chiral amine nitrogen centers of [Co(acac or ox)2(Me-en or Me3en)]+or− in aqueous solutions were measured at 34.0 °C, and the results were compared with one another and with those of related complexes. The deuteration rate is affected more by the nature of coexisting ligands than the overall charge on the complex. The uninegative ox complexes have larger kD values than the unipositive acac complexes. The kep values of the ox complexes are ca. 104 times as large as those of the acac complexes. For both ox and acac complexes, the complexes with Me3en have larger kD and kep values than the complexes with Me-en. The deuteration rates are ca. 104–105 and ca. 102 times greater than the inversion rates for the acac and ox complexes, respectively.
Preparation and Crystal Structure of New Gold(I) Complexes Linked to Pyrimidines
Authors: Amagai Takashi , Miyamoto T Ken , Ichida Hikaru , Sasaki Yukiyoshi 
Published: July 2006

Abstract
Two new gold(I) complexes linked to pyrimidines, (5-fluoro-2′-deoxyuridinato-N3)(triphenylphosphine)gold(I) (1) and [5-fluoro-1-(tetrahydro-2-furanyl)-2,4(1H,3H)-pyrimidinedionato-N3](triphenylphosphine)gold(I) (2) were synthesized and characterized by 31P, 1H NMR and IR spectra. The structure of 2 was determined by an X-ray diffraction method. A linear, two-coordination around gold(I) has been shown. In order to estimate the possible alteration of 1 and 2 in vivo, several factors such as the effect of pH, and reactions with thiol, thiophenol, and imidazole were examined.
Efficient Synthetic Method for Differentially Protected Naturally Occurring Acyclic Polyamines
Authors: Iwata Masaaki , Kuzuhara Hiroyoshi 
Published: July 2006

Abstract
A new systematic route to threefold protected natural polyamines, spermidine, spermine, thermine, and thermospermine, was developed through alternate regioselective manipulation on the terminal primary amino groups, starting from N,N-phthaloyl-1,3-propanediamine hydrochloride (3). When 3 was tosylated at the amine terminal and the phthaloyl terminal was subjected to transformation to the formamido group followed by substitution at the tosyl terminal with, e.g., N-(4-bromobutyl)phthalimide, threefold protected spermidine was obtained in excellent yield. After hydrolysis of the formamido group to amine salt, a sequence of the reactions was satisfactorily repeated to afford various types of threefold protected natural tetramines.
Induced Circular Dichroism Spectrum of α-Cyclodextrin Complex with Heptylviologen
Authors: Kodaka Masato , Fukaya Toshio 
Published: July 2006

Abstract
The rotational strength of α-cyclodextrin (α-CDx) complex with heptylviologen (1,1′-diheptyl-4,4′-bipyridinium dibromide) was calculated by using the Kirkwood–Tinoco expression. The calculation shows that electric transition polarized along the long axis of heptylviologen gives negative induced circular dichroism (ICD) whereas the short-axis polarized transition gives positive ICD, when HV is axially included in α-CDx and the electric transition moment is located out of the cavity of α-CDx (above the narrower rim). From the comparison between the experimental and calculated results, it is concluded that the heptyl chain of heptylviologen is involved in the cavity while the pyridinium part is situated out of the cavity.
Synthesis and Properties of the Tridecafulvene Derivatives. The Substituent Effect at the 14-Position on the Tropicity of Thirteen-Membered Fulvene System
Authors: Ojima Juro , Masumoto Masayuki , Katsuyama Jyunji , Kitamura Keiko , Iyoda Masahiko 
Published: July 2006

Abstract
Dimethylbisdehydrotridecafulvene derivatives bearing various substituents at the exocyclic bond have been synthesized and the inductive effect of substituents upon the tropicity of the thirteen-membered ring is discussed on the basis of the spectral data.
Polarography of Metal Hydroxamates. Individual and Simultaneous Determination of Tungsten and Molybdenum Using Benzo- and Cinnamohydroxamic Acids
Authors: Bhowal Sabooj Kumar , Bhattacharyya Mita 
Published: July 2006

Abstract
Methods for the determination of traces of tungsten have been developed by directly subjecting the organic extracts of its benzo- and cinnamohydroxamic acid complexes to d. c. and derivative pulse polarography. Well defined waves and peaks are obtained in a ternary solvent mixture containing the extract, methanolic lithium chloride and aqueous phase. The methods are highly selective and allow determination of the metal in the ppm range. A procedure has also been developed for the simultaneous determination of tungsten and molybdenum using their benzohydroxamates. Effects of acids and solvents on the system have been studied and the probable mechanism of reduction of the complexes has also been discussed.
Synthesis and Reactions of 2-Arylhydrazinotropones. II. Synthesis of 5-Aryltropolones and B-Ring-Open Colchicine Analogues via Benzidine Type Rearrangement of 2-(2-Arylhydrazino)troponesa
Authors: Nozoe Tetsuo , Takase Kahei , Yasunami Masafumi , Ando Masayoshi , Saito Hiroaki , Imafuku Kimiaki , Yin Bing-Zhu , Honda Masaaki , Goto Yasutomo , Hanaya Tadashi , Hara Yasushi , Yamamoto Hiroshi 
Published: July 2006

Abstract
Treatment of a wide variety of 2-(2-arylhydrazino)tropones with ethanolic acid at 50–80°C readily gave the benzidine type rearrangement products, 2-amino-5-(4-aminoaryl)tropones, besides minor amounts of byproducts of various type. The main products were conveniently led to the corresponding 5-aryltropolones. Similarly, 2-(2-arylhydrazino)tropones bearing an isopropyl and isopropenyl group at the 4-position afforded 4-substituted 2-amino-5-(4-aminoaryl)tropones as the main products, which were also led to 4-substituted 5-(4-acetamidoaryl)- and 5-(4-methoxyaryl)tropolones. Structural assignments of these products were made on the basis of 1H NMR and other spectral data as well as of chemical transformations to known 5-phenyltropolone and also to 2-acetamido-8-hydroxy-10,10-dimethylcyclohept[a]inden-7(10H)-one. This synthetic scheme may possibly be utilized for a convenient synthesis of B-ring-open analogues of colchicine.
Direct Determination of the Intermolecular Potential for Krypton
Authors: Boushehri Ali , Absardi Jalil Moghadasi 
Published: July 2006

Abstract
In recent years a procedure has been developed for determining potential energy functions directly from measurements of gaseous transport properties, without assuming any particular functional form for the interaction potential. Previous applications of this procedure have required that the potential well depth be known independently. It is shown that this requirement is not necessary, and that the entire potential can be directly obtained with reasonable accuracy from the accurate viscosity data presently avilable. The interaction potential discussed is that for the inert gases.
Crystal and Molecular Structure of the Dicobalt(III) Complex Containing Bridging Di-μ-hydroxo Ligands, [(gly)(en)Co(μ-OH)2Co(gly)(en)]2+
Authors: Hamada Kensaku , Ohta Etsuko , Fujiwara Takaji , Ama Tomoharu 
Published: July 2006

Abstract
The molecular and crystal structure of the title compound has been determined by the X-ray method. The cation structure consists of well-separated dimeric pairs of the octahedrally coordinated cobalt(III) atom linked by two μ-hydroxo bridges. There are two intramolecular N–H···O hydrogen bonds bridging the two chromophores.
The Amidation of Carboxylic Acid with Amine over Hydrous Zirconium(IV) Oxide
Authors: Takahashi Kyoko , Shibagaki Makoto , Kuno Hideyuki , Kawakami Hiroshi , Matsushita Hajime 
Published: July 2006

Abstract
The reaction of a carboxylic acid or an ester with an amine to give the corresponding amide was carried out efficiently over hydrous zirconium(IV) oxide, whether in the vapor phase or in the liquid phase.
Kinetics of the Thermal Intramolecular Redox Reaction of Pentaamminenitrosylcobalt(III) Chloride in the Solid State
Authors: Miyokawa Kikuo , Masuda Hakaru , Wakita Hisanobu 
Published: July 2006

Abstract
The kinetics of the thermal intramolecular redox reaction between NO− and Co(III) in [Co(NH3)5NO]Cl2 has been studied by means of thermogravimetric and thermomagnetic analyses. The reaction is found to follow the first-order equation, with ΔH\eweq=129±6 kJ mol−1 and ΔS\eweq=14±16 J mol−1 K−1. These results are compared with the kinetics of other nitrosylcobalt(III) and hexaamminecobalt(III) complexes.
A Glassy Carbon Electrode Modified with N-(2-Hydroxybenzyl)chitosan for Voltammetric Determinations of Cu2+ and Pb2+
Authors: Kurauchi Yoshiaki , Tsurumori Eiichi , Ohga Kazuya 
Published: July 2006

Abstract
A glassy carbon electrode was chemically modified with N-(2-hydroxybenzyl)chitosan which could act as an agent to preconcentrate Cu2+ and Pb2+. The modified electrode was stable for 30 d and its calibration curves for the voltammetric determination of these ions are linear in the concentration range of (1–10)×10−7 mol dm−3. The usage limitation of this electrode has also been discussed.
Photochemical Decarbonylation of (α-Arylacyl)triphenylgermane
Authors: Kiyooka Syun-ichi , Shibuya Tsutomu , Shiota Fuminori , Fujiyama Ryoji 
Published: July 2006

Abstract
(α-Arylacyl)triphenylgermanes were prepared from the corresponding esters with triphenylgermyllithium at room temperature in good yields. Photochemical decarbonylation of (α-arylacyl)triphenylgermanes took place under UV irradiation to quantitatively give (α-arylalkyl)triphenylgermanes without by-products.
A Lattice Gas Model for Neopentane
Authors: Shinmi Masato , Huckaby Dale A 
Published: July 2006

Abstract
A lattice gas model for neopentane on a bcc lattice was considered. The equation of state and critical point were calculated using a Guggenheim–McGlashan approximation. The liquid phase in the model exhibits the same type of short-range orientational ordering proposed by Nishikawa to exist in liquid neopentane.
Reduction of Halonitrobenzenes with Disodium Ditelluride in N,N-Dimethylformamide
Authors: Zingaro Ralph A , Herrera Chris 
Published: July 2006

Abstract
The reaction of disodium ditelluride in N,N-dimethylformamide with o-halonitrobenzenes results in displacement of the halide, reduction of the nitro group and a ring closure reaction which yields phenazines.
Structural Features and Biological Studies of Dioxomolybdenum(VI) Complexes of Thiosemicarbazones
Authors: Kanoongo Neeta , Singh Ranvir , Tandon Jagdish Prasad 
Published: July 2006

Abstract
Synthesis, characterization, and spectral features of six-coordinated dioxomolybdenum(VI) complexes of the type, [MoO2(tscz)2] (where Htscz represents the thiosemicarbazone moiety) are reported. These have been characterized by elemental analysis, conductance measurements, molecular weight determinations, and magnetic studies. Based on IR, 1H NMR, 13C NMR, and electronic spectral studies, an octahedral geometry with cis-MoO2 structure has been proposed. The antibacterial and fungicidal activities of two representative ligands and their dioxomolybdenum complexes have also been evaluated and discussed.
A Simple Iterative Approach to the Synthesis of cis-cisoid-cis-Tricyclo[6.3.0.02,6]undecane Carbon Skeleton
Authors: Vankar Padma S , Chandrasekaran Srinivasan 
Published: July 2006

Abstract
In an iterative synthesis utilizing only four reagents, cyclopentanone has been converted into cis-cisoid-cis-tricyclo[6.3.0.02,6]undecane carbon skeleton in high yield.
Optical Resolution of C3 Cyclotriveratrylenes and D3 Cryptophanes by Liquid Chromatography on Chiral Stationary Phase Chiralpak-OT(+)
Authors: Tambuté André , Canceill Josette , Collet André 
Published: July 2006

Abstract
A series of C3 Cyclotriveratrylenes and D3 cryptophanes have been resolved by HPLC on Chiralpak-OT (+), allowing the first direct enantiomeric excess assessments for these substances. These results confirm the usefulness of this chiral stationary phase for the resolution of aromatic compounds and extend its scope of application to new classes of highly symmetrical molecules.
Two-Bond Deuterium Isotope Effects on 13C Chemical Shifts of Phenols
Authors: Nakashima Yasuki , Yoshino Akihiro , Takahashi Kensuke 
Published: July 2006

Abstract
Two-bond deuterium isotope effects on 13C chemical shifts of 28 substituted phenols are reported and explained in terms of the additivity of substituent parameters which are correlated with the SCS of 13C NMR.
The Crystal and Molecular Structures of Two 1:2 Complexes of 1,4-Diazabicyclo[2.2.2]octane (DABCO) with 1-(o-Chlorophenyl)1-phenyl-2-propyn-1-ol (CPPOH), and Those of Two 1:2 Complexes of N,N′-Dimethylpiperazine (DMP) with CPPOH
Authors: Yasui Masanori , Yabuki Tetsuro , Takama Masaaki , Harada Shigeharu , Kasai Nobutami , Tanaka Koichi , Toda Fumio 
Published: July 2006

Abstract
X-Ray crystal structure analysis of the title four complexes showed that crystals consist of CPPOH···achiral diamine···CPPOH units. In the first two crystals a DABCO molecule is bound by two (−)-CPPOH molecules (1) or by (+)- and (−)-CPPOH (2) to form 1:2 complex by strong intermolecular O–H···N hydrogen bonds [O–H···N=2.707(3) and 2.755(3) (1) and 2.704(4) and 2.747(4) Å (2)]. The latter two crystals are respectively formed by (+)-CPPOH···DMP···(−)-CPPOH complex (3) [O–H···N=2.771(3) Å] and (−)-CPPOH···DMP···(−)-CPPOH complex (4) [O–H···N=2.768(5) and 2.730(6) Å].
The Model Compounds and the Conformational Analysis of Poly(thiomethylene)
Authors: Miyasaka Taira , Yoshida Takaichi 
Published: July 2006

Abstract
The conformational energies of model compounds of poly(thiomethylene), CH3(SCH2)nSCH3, (n=1–6) were calculated by the molecular-mechanics method. Based on these conformational energy differences, the configuration-dependent properties of poly(thiomethylene) were estimated under the rotational isomeric-state approximations. The first-order interaction energy of the (Remark: Graphics omitted.) bond, obtained from the energy differences among the conformers of CH3(SCH2)3SCH3, is coincident with that estimated from the same bond sequence for poly(1,3-dithiocane). Based on this coincidence, the monomeric sequential length of the model compound, which is representative of poly(thiomethylene), was decided. The propriety of the method of coupling the molecular-mechanics with the statistical-mechanics was also demonstrated.
Preferential Solvation of Ni(II) and Mg(II) Ions in Water–Acetonitrile Mixtures. Enthalpies of Transfer and the Electronic Spectra
Authors: Miyaji Kiyoshi , Nozawa Kiyokazu , Morinaga Kenichi 
Published: July 2006

Abstract
The enthalpies of transfer (ΔHt°) from water to water-acetonitrile (W–AN) mixtures for Ni2+ and Mg2+ ions were estimated using the enthalpies of dilution of the concentrated aqueous electrolyte solutions into water and mixtures, and the enthalpies of solution of water in the mixtures. The ΔHt° values for these ions decreased with an increase in the mole fraction of AN (xAN) in the range of xAN&lt;ca. 0.9, however, they increased rapidly in the range xAN&gt;ca. 0.9. The values of ΔHt° for the Ni2+ ion were more negative than those for the Mg2+ ion throughout the xAN regions, especially in the extremely AN-rich region and in pure AN. The average number of coordinated water molecules, N, for the [Ni(AN)6−N(W)N]2+ ion in the mixtures (xAN=0.2, 0.6, and 0.9), as estimated from the electronic absorption spectra, was always greater than that calculated on the basis of the bulk-solvent composition, indicating that the Ni2+ ion was preferentially solvated by water. These results, including the conductance data, were discussed in terms of the principle of hard and soft acid and base.
Reduction of N3− by [Mo2Fe6S8(SPh)9]3− Modified Glassy Carbon Electrode—Model Study of Nitrogenase
Authors: Tanaka Koji , Kuwabata Susumu , Denno Satoshi , Tanaka Toshio 
Published: July 2006

Abstract
The reduction of N3− by a (Bu4N)3[Mo2Fe6S8(SPh)9] modified glassy carbon electrode has been conducted in a pH region 5 to 12 in water. In neutral and acidic conditions, N3− undergoes two-and six-electron reductions to afford not only N2 and NH3 but also N2H4, and the total amounts of N2 and N2H4 produced were essentially consistent with that of NH3. On the other hand, no N2H4 formation was observed in the pH region higher than 10, where an equal amount of N2 and NH3 was formed. The rate of N2H4 formation was linearly proportional to a concentration of N3H, which exists as an equilibrium mixture with N3− in the aqueous phase, while that of N2 evolution was controlled by the concentration of free N3− in H2O. These observations indicate that N2H4 and N2 result from the coordination of N3H and N3− to the molybdenum–iron sulfur cluster, respectively.
Dinuclear Complexes of Tetrathia[10]metallocenophanes with Silver(I) Ion: Slightly Distorted Square-Pyramidal Coordination of Ag(I) Ion
Authors: Akabori Sadatoshi , Sato Sadao , Sato Masaru , Takanohashi Yoshinori 
Published: July 2006

Abstract
Tetrathia[10](1,1′)ferrocenophane reacts with silver(I) perchlorate and/or trifluoromethamesulfonate to form dimeric 1 : 1 complexes (2c and 2d) in 73 and 60% yields, respectively. The corresponding complexes (2a and 2b) of tetrathia[10](1,1′)ruthenocenophane were also obtained in 45 and 33% yields, respectively. The crystal structure of complex 2c was determined by the X-ray method. The crystal data: monoclinic, space group P21⁄a, a=19.227(3), b=10.619(3), c=9.739(2) Å, β=91.71(2)°, U=1987.8 Å3, Dc=2.02 g cm−3, Z=4, μ(Mo Kα)=23 cm−1, R=0.075. In complex 2c the inner coordination sphere of the silver is completed by a sulfur atom of another ligand bonded axially to produce a five-coordinate silver ion with an overall slightly distorted square-pyramidal geometry. The temperature dependence of the 1H NMR spectra of 2 was also examined. The rate between the silver free ligand 1a and complex 2b at room temperature was very first by the 1H NMR scale.
Syntheses and Properties of Quinonoid Mesoionic Compounds
Authors: Araki Shuki , Aoyama Naomitsu , Butsugan Yasuo 
Published: July 2006

Abstract
Quinonoid mesoionic compounds having a 2,3-diphenyltetrazolium ring were synthesized and characterized spectroscopically. Compounds possessing an inserted benzene ring were found that a dipolar (5-tetrazolylio)phenolate structure contributes importantly to the ground state of the mesoions. On the contrary, a mesoion having an inserted anthracene ring is a less polar compound, anthraquinone methide structures being dominant in its ground state electronic structure.
Synthesis, Structure, and Properties of Triple-Layered [2.2][2.2]Naphthalenophane
Authors: Otsubo Tetsuo , Aso Yoshio , Ogura Fumio , Misumi Soichi , Kawamoto Atsushi , Tanaka Jiro 
Published: July 2006

Abstract
The title compound was synthesized in a similar manner to a simple access to triple-layered [2.2][2.2]paracyclophane. Its structure was elucidated by X-ray crystallographic analysis. The outer naphthalene rings are bent into a boat form and the inner naphthalene ring is bent into a twist form. These naphthalenes are stacked in layers within van der Waals contact. Therefore, there is a strong transannular π-electronic interaction between them, which brings about characteristic bathochromism, hyperchromism, and broadening in the electronic spectrum. These effects are more prominent than those of the double-layered homologue.