bluuebunny/crossref_metadata_2025_split huggingface dataset:
Triple Ion and Quadrupole Formations from Trialkylammonium Sulfonates and Nitrate in Protophobic Aprotic Solvents with Higher Dielectric Constants
Authors: Hojo Masashi , Miyauchi Yoshihiro , Imai Yoshihiko 
Published: July 2006

Abstract
The formation of symmetrical triple ions (2M++X−\ightleftarrowsM2X+, (K2); M++2X−\ightleftarrowsMX2−, (K3); K2=K3) and the quadrupole (M2X++X−\ightleftarrowsM2X2, (K4); MX2−+M+\ightleftarrowsM2X2, (K5); K4=K5), in addition to the ion pair formation (M++X−\ightleftarrowsMX, (K1)) from uni-univalent salts (MX) has been examined in acetonitrile (dielectric constant ε=35.95), benzonitrile (ε=25.2), nitrobenzene (ε=34.82), and nitromethane (ε=36.67) at 25° by means of conductometry. Tho molar conductivities (Λ) of tributylammonium methanesulfonate (n-Bu3NHCH3SO3) of (0.4–6.0) ×10−3M (1 M=1 mol dm−3) in benzonitrile were explained by the formation of triple ions (Ka1=8.4×104, Ka2=Ka3=5.5×105, corrected by the activity coefficients of ions) within ±0.85% relative error, assuming that ΛT=ΛO⁄3 (ΛT: the limiting molar conductivity of the triple ions; ΛO: that of the simiple ions). In nitrobenzene, however, the quadrupole formation must be invoked for the salt in the same concentration range (Ka1=1.38×105, Ka2=Ka3=4.75×107, Ka4=Ka5=8.5×102). The alternative formation constant of the quadrupole (2MX\ightleftarrowsM2X2, (K41)) was evaluated as Ka41=5.0 instead of Ka4. Triple ion formation was observed in acetonitrile and nitromethane, but not in an amphiprotic solvent, ethanol (ε=24.55). The tendency for triple ion formation or higher aggregate formations from trialkylammonium salts was found to decrease as follows: Cl−&gt;CH3SO3−, Br−&gt; TsO−, NO3−&gt;I−, CF3SO3−&gt; (ClO4−). The difference in the aggregate forming ability is discussed from the view point of basicity of the anions, the strength for a proton acceptor in hydrogen bonding, and the localization of electrons in the anion molecule.
Regio- and Facial-Selective Effects of Allylic Heteroatoms in 1,3-Dipolar Cycloaddition of a Nitrile Oxide
Authors: Inouye Yoshinobu , Mitsuya Morihiro , Tokuhisa Kenji , Kakisawa Hiroshi 
Published: July 2006

Abstract
The 1,3-dipolar cycloaddition of nitrile oxides to 2-X-bicyclo[2.2.2]oct-5-enes (X=O, NMe, S, SO2) were investigated together with acyclic and alicyclic analogues. The regioselectivity in an exo-attack was controlled by the heteroatom present at an allylic position —a remote attack was predominant in the cases of O and SO2 but a vicinal attack in those of NMe and S— and the results were rationalized from the electronic nature of the heteroatom, X. In an endo-attack, a remote attack was observed in every case and the dipole-dipole repulsion between X and the oxygen of the nitrile oxide was considered to be a predominant factor. The steric environment around the heteroatom controled the facial-selectivity.
Observation of Atomic Corrugation on Au(111) and Iodine on Pt(111) in Air
Authors: Sashikata Kenji , Honbo Hidetoshi , Furuya Nagakazu , Itaya Kingo 
Published: July 2006

Abstract
The STM images acquired in the constant current mode were found to resolve individual close-packed gold atoms on Au(111) and iodine atoms on Pt(111). Measurements were made in air on the facets formed on single crystal spheres. Single crystals were prepared by melting pure metal wires with a hydrogen–oxygen flame.
Template Synthesis and Crystal Structure of a Dilead(II) Complex of a Macrocycle with N4O2 Donor Set
Authors: Tadokoro Makoto , Sakiyama Hiroshi , Matsumoto Naohide , Okawa Hisashi , Kida Sigeo 
Published: July 2006

Abstract
A dilead(II) complex of a binucleating macrocycle formed by the condensation of two molecules of 2,6-diformyl-4-methylphenol and two molecules of 1,3-diaminopropane has been obtained by template reaction. The crystal structure of this complex was analyzed by single-crystal X-ray method.
The Structure of 4-Methoxy-ONN-azoxybezene and Oxygen Transfer Reaction of 4-Methoxyazoxybenzenes in Sulfuric Acid
Authors: Yamamoto Jiro , Yamashita Hiroshi , Miyagawa Hisato , Abe Toshio , Tsukihara Tomitake 
Published: July 2006

Abstract
The structure of 4-methoxy-ONN-azoxybenzene (1α) has been determined by X-ray analysis. In sulfuric acid 1α gave a rearrangement product 4-hydroxy-4′-methoxyazobenzene, together with 4-methoxyazobenzene and 4-methoxy-NNO-azoxybenzene.
Synthesis and Binding Properties of Ethylbipyridinio-Modified β-Cyclodextrin
Authors: Du Yi-qun , Nakamura Asao , Toda Fujio 
Published: July 2006

Abstract
Mono-6-deoxy-6-[4-(1-ethyl-4-pyridinio)-1-pyridinio]-β-cyclodextrin (3) was synthesized. The conformation and the binding properties of 3 with benzene derivatives were examined by induced circular dichroism (ICD) in aqueous solution. The conformation of 3 was confirmed to such equatorial inclusion as β-CDx capped by ethylviologen (C2V2+) group. Further, compound 3 showed stronger binding ability with these guests (1:1 complexes) compared with β-cyclodextrin (β-CDx).
Application of the SPE Method to Organic Electrochemistry-X. Behaviors of the Manganese Redox Couple Incorporated in Pt–Nafion and Their Mediatory Oxidation of Cinnamyl Alcohol to Cinnamaldehyde
Authors: Ogumi Zempachi , Mizoe Toshiyuki , Zhen Chen , Takehara Zen-ichiro 
Published: July 2006

Abstract
The electrochemical behavior of a manganese redox couple incorporated into an SPE (Solid Polymer Electrolyte) composite electrode using Nafion (Pt–Nafion) was examined as a mediator for electroorganic syntheses. The mediatory reaction of the redox couple was examined in the oxidation of cinnamyl alcohol. The oxidation proceeded smoothly and gave cinnamaldehyde in high selectivity; the current efficiency was as high as 85%. The dissolving-out of manganese from the SPE was suppressed by the addition of 0.025 mol dm−3 MnSO4 to the catholyte.
Femtosecond-Picosecond Laser Photolysis Studies on Photoreduction Process of Excited Benzophenone with N,N-Dimethylaniline in Acetonitrile Solution
Authors: Miyasaka Hiroshi , Morita Kazuhiro , Kamada Kenji , Mataga Noboru 
Published: July 2006

Abstract
Photoreduction processes of excited benzophenone (BP) by N,N-dimethylaniline (DMA) in acetonitrile solution were studied by means of picosecond-femtosecond laser photolysis and time resolved transient absorption spectroscopy as well as transient photoconductivity measurement. Proton transfer process in the triplet ion pair formed by electron transfer (ET) at encounter between 3BP* and DMA, competing with the ionic dissociation process was observed. It was clearly demonstrated that, in addition to the triplet ion pair, the ion pair produced by the excitation of the CT complex between BP and DMA formed in the ground state and that produced by ET reaction between 1BP* and DMA played important roles in the reaction processes of excited benzophenone. The behaviors of the three kinds of ion pairs were investigated in detail, leading to the elucidation of reaction mechanism of each ion pair. The reactivity characteristic of each kind of the ion pair and its relation to the structure of the ion pair were discussed.
Splitting of the 2nd d–d Band of trans-[CoCl2N4]X-Type Complexes Observed in the Solid State at 113 K
Authors: Tsuchimoto Masanobu , Kita Masakazu , Fujita Junnosuke 
Published: July 2006

Abstract
The electronic spectra of trans-[CoCl2(NH3)4]Cl and its analogues measured in the solid state at 113 K show four ligand field bands assignable to the Ia(1Ega← 1A1g), Ib(1A2g← 1A1g), IIa(1B2g← 1A1g), and IIb(1Egb← 1A1g) transitions in D4h approximation. The ligand field parameters obtained from the observed data are; eσ(N)=7400–8000 cm−1, eσ(Cl)=4500–5400 cm−1, eπ(Cl)=300–830 cm−1, and the Racah’s parameter C estimated with the assumption of C=4B is ca. 2000 cm−1. A nearly linear relationship is obtained between the eσ(Cl) and eπ(Cl) values; the stronger the coordination of Cl− to Co(III), the stronger the π interaction of Cl− with Co(III).
In Situ Observations of the Phase Transition among Cobalt(II) Dichloride Hydrates and Crystal Structures of the Tetra- and Hexahydrates
Authors: Waizumi Kenji , Masuda Hideki , Ohtaki Hitoshi , Tsukamoto Katsuo , Sunagawa Ichiro 
Published: July 2006

Abstract
Transformation among cobalt(II) dichloride hydrates in aqueous solutions was studied by the optical microscopic method. Although there are three hydrates (CoCl2·6H2O, CoCl2·4H2O, and CoCl2·2H2O) in the phase equilibrium diagram, the only solution mediated transformation between CoCl2·6H2O and CoCl2·2H2O could be observed under the present experimental conditions and it was confirmed that CoCl2·4H2O hardly formed compared with the other two hydrates. In order to investigate the reason why CoCl2·4H2O was hardly crystallized at the transformation from CoCl2·6H2O through CoCl2·2H2O and vice versa, the crystal structure of CoCl2·4H2O was investigated by the X-ray diffraction method. The structure of CoCl2·6H2O was reexamined because previously reported results had a relatively large R-factor. The crystal of CoCl2·4H2O is monoclinic, space group P21/a with a=11.548(1) Å, b=9.342(1) Å, c=6.056(1) Å, β=110.79(1)°, and Z=4. The complex has a slightly distorted octahedral geometry about Co2+ ion and two Cl− ions are located at the cis-position. The crystal of CoCl2·6H2O is monoclinic, space group C2/m with a=10.380(2) Å, b=7.048(1) Å, c=6.626(1) Å, β=122.01(1)°, and Z=2. The geometry around the cobalt ion is also octahedral with four water molecules and two chloride ions at the equatorial and the axial positions, respectively. The remaining two water molecules are linked to the two Cl− ions by hydrogen bonding. The difficulty of crystallization of CoCl2·4H2O crystals in solutions was explained in terms of the relatively unstable cis-dichloro structure of the [CoCl2(H2O)4] moiety and its crystal structure stabilized by hydrogen bonding network between the cis-form moieties.
Photo-Cycloaddition Reactions of 2-Pyrones
Authors: Somekawa Kenichi , Shimo Tetsuro , Yoshimura Hiroyuki , Suishu Takaaki 
Published: July 2006

Abstract
Sensitized photoreactions of two 2-pyrones with five unsaturated compounds were investigated. The reactions of 2-pyrones with electron-deficient ethylenes gave [4+2]cycloadducts (3) and [2+2]cycloadducts (4) across the C5–C6 double bonds in the 2-pyrones. On the other hand, reactions with an electron-donating ethylene, ethyl vinyl ether (2i), gave other kinds of [2+2]cycloadducts (5) and a [4+2]cycloadduct (6), site- and regio-selectively. These two kinds of reactions were inferred to start at the C-6 and C-4 positions of the 2-pyrones to give 3 or 4, and 5 or 6, respectively. The regioselectivity of 6 was opposite to that for a thermal [4+2]cycloadduct (7). The substituents on 2-pyrones also influenced the product-distribution and the triplet energy-level.
An ESR Study of Aromatic Olefin Radical Cations
Authors: Bonazzola Lydia , Michaut Jean-Pierre , Roncin Jacques , Misawa Hiroaki , Sakuragi Hirochika , Tokumaru Katsumi 
Published: July 2006

Abstract
γ-Irradiation of phenyl- and diphenylethenes in CFCl3 matrix at 77 K resulted in the formation of the substrate radical cations. 1,1-Diphenyl-2-methylpropene radical cations exhibit a spin density (ρ=0.45) at the β carbon much higher than those of stilbene and 2-styrylnaphthalene radical cations and comparable to those of styrene and α-methylstyrene radical cations. The spin density at the vinyl carbons appears to play an important role in governing the reactivity of the olefin radical cations with molecular oxygen.
Preparation of New Nitrogen-Bridged Heterocycles. 25. A Smooth Synthesis of [1,4]Thiazino[3,4,5-cd]indolizine Derivatives
Authors: Kakehi Akikazu , Ito Suketaka , Fujii Tsuneo , Sakurai Tosio , Urushido Kunio , Hatanaka Susumu , Mabuchi Toshiaki , Matsushita Shun-ichiro 
Published: July 2006

Abstract
The title compounds were prepared smoothly in moderate yields by the reactions of 3-(mercaptomethylene)-2(3H)-indolizinones with various alkylating agents such as bromoacetonitrile, bromoacetates, and phenacyl bromides in the presence of base. The structural assignments of these products were accomplished by their spectral inspections, and the structure for one compound was distinctly proven by its X-ray crystallography. In order to explain the regioselectivity in this reaction, a molecular orbital calculation (CNDO/2) was also performed using a model compound.
The Application of Diarylamine Compounds in Analytical Chemistry. 1 Fluorescence Reactions among 4-(4-Methyl-2-quinolyl)aminosalicylic Acid, Cobalt(II) and Hydrogen Peroxide, and the Fluorimetry of Cobalt(II) by Using Its Fluorescence Reaction
Authors: Mori Itsuo , Fujita Yoshikazu , Kato Keiji , Toyoda Minako , Akagi Masao 
Published: July 2006

Abstract
The fluorescence reactions among 4-(4-methyl-2-quinolyl)aminosalicylic acid (MQAS) as a diarylamine compound, hydrogen peroxide as an oxidizing agent, and various metal ions such as cobalt(II) were spectrolluorometrically investigated in the presence or in the absence of various surfactants. The MQAS–hydrogen peroxide solution in the presence of trimethylstearylammonium chloride (STAC) as a cationic surfactant was catalytically converted to a fluorescence product by the coexistence of trace amounts of cobalt(II), and its relative fluorescence intensity at 400 nm in the fluorescence reaction product was proportional to the cobalt(II) concentrations. Moreover, a highly selective and sensitive fluorimetric method for the determination of cobalt(II) using MQAS and hydrogen peroxide in the presence of STAC in basic media was proposed. The calibration graph was linear in the range of 0–45 ng cobalt(II) per 10 cm3 at an emission wavelength of 400 nm, with an excitation wavelength of 320 nm.
Solvent Effect on the Dissociation of Benzoic and Nitrobenzoic Acids in Acetonitrile–Water Mixtures at 298 K
Authors: Niazi M S K , Ali J 
Published: July 2006

Abstract
The thermodynamic dissociation constants and the limiting molar conductivities of 2-, 3-, and 4-nitrobenzoic and benzoic acids have been determined in water–acetonitrile mixtures at 298 K. It is found that the acids dissociate in the dereasing order as 2-nitrobenzoic acid &gt; 3-nitrobenzoic acid≈4-nitrobenzoic acid &gt; benzoic acid. The conductance–concentration data were analyzed with the Lee and Wheaton equation. The present results are compared with the previous ones for these acids in alcohol–water system, and are interpretted in terms of solute–solvent interactions, intramolecular hydrogen bondings, resonance and inductive effects along with the substituent position.
Structural, Magnetic and Spectroscopic Characterization of Novel Di-μ-carboxylato-Bridged Binuclear Copper(II) Complexes with 1,10-Phenanthroline
Authors: Tokii Tadashi , Watanabe Naofumi , Nakashima Michio , Muto Yoneichiro , Morooka Mitsuo , Ohba Shigeru , Saito Yoshihiko 
Published: July 2006

Abstract
Bis(μ-carboxylato-O,O′)-diaquabis(1,10-phenanthroline)dicopper(II) dinitrate tetrahydrates, [Cu(RCOO)(phen)(H2O)]2(NO3)2·4H2O, where R=H, CH3, and (CH3)3C, were prepared and characterized by elemental analyses, electronic spectra, magnetic susceptibilities, and X-ray structure analysis. The magnetic susceptibility data conform to the usual dimer equation. The −2J values are 125 cm−1 for formate, 86 cm−1 for acetate, and 99 cm−1 for 2,2-dimethylpropanoate. The crystal structures of [Cu(HCOO)(phen)(H2O)]2(NO3)2·4H2O (1) and [Cu(CH3COO)(phen)(H2O)]2(NO3)2·4H2O (2) were determined by the single-crystal X-ray diffraction method. The crystallographic data are: Compound 1, monoclinic, I2⁄a, a=18.850(2), b=9.775(2), c=17.752(2) Å, β=99.03(1)°, V=3230.4(8) Å3, Z=4, R=0.055 for 2511 observed unique reflections; Compound 2, monoclinic, C2⁄c, a=18.563(4), b=14.272(5), c=14.126(3) Å, β=106.72(2)°, V=3584(2) Å3, Z=4, R=0.082 for 2092 reflections. The complexes consist of dimeric [Cu(RCOO)(phen)(H2O)]22+)] cations with five-coordinated copper ions linked by two carboxylato ions in a syn-syn bridging arrangement. The Cu···Cu distances are 3.103(2) Å for 1 and 3.063(3) Å for 2.
Synthesis, Ion-Exchange Properties, and Analytical Applications of Anilinium Zirconium(IV) Phosphate
Authors: Singh Dhruv Kumar , Mehrotra Pallavi 
Published: July 2006

Abstract
A new inorganic ion exchanger, anilinium zirconium(IV) phosphate (AZP), has been prepared under varying conditions. The effects of mixing ratio of reagents and the pH of the mixture on the ion-exchange properties of the material have been studied. The detailed studies, such as ion-exchange capacity, chemical and thermal stabilities, chemical composition, pH titration, and IR analysis were made. Distribution coefficients of metal ions have been studied in water, nitric acid, 1,4-dioxane, aqueous ammonium nitrate, thiourea–nitric acid, and thiourea–hydrochloric acid media. Some analytically important separations of metal ions have been achieved on the small columns of AZP.
Partial Molar Volumes of Sodium Perfluoroalkanoates and Lithium Perfluoro-1-alkanesulfonates in Aqueous Solutions
Authors: Tamaki Kunio , Watanabe Sumiko , Daikyoji Yuichi 
Published: July 2006

Abstract
The densities of aqueous solutions of sodium perfluoroalkanoates, F(CF2)nCOONa (n=1–4, 6, 7) and lithium perfluoro-1-alkanesulfonates, F(CF2)nSO3Li (n=1, 4, 8) were measured at 25°C, and the limiting partial molar volumes were calculated. The assignment of group partial molar volumes is discussed.
A Method for Measuring Surface Area of Carbon of Carbon-Coated Silica Gel
Authors: Kamegawa Katsumi , Yoshida Hisayoshi 
Published: July 2006

Abstract
An adsorption method for determining the surface area of only the carbon of carbon-coated silica gel has been developed. In this method p-nitrophenol (PNP) was used as an adsorbate owing to its selective adsorbability on a carbon surface. This method was applied to carbon-coated silica gel prepared by a CVD method to determine the surface area of the carbon.
Vacuum Sublimation Behavior of Nickel(II), Palladium(II), and Platinum(II) Chelates with Dimethylglyoxime
Authors: Suzuki Itaru , Honjo Takaharu , Terada Kikuo 
Published: July 2006

Abstract
A sublimation apparatus in perpendicular style with a continuous-temperature gradient (30–200 °C) along the glass tube (15–0 cm) at 10−2 Torr (1 Torr=133.322 Pa) was used.
Dimethylglyoxime (DMG) and its chelates of nickel(II) and palladium(II) in milligram amounts were sublimed without any thermal decomposition, while platinum(II) chelate was accompanied by a remarkable thermal decomposition during the sublimation process. All metal chelates, Ni(DMG)2 (brick-red), Pd(DMG)2(yellow), and Pt(DMG)2 (grayish violet), form needle-like crystals after purification with a sublimator under low pressure.
The Reactions of Optically Pure Menthyloxymethylphenylphosphine-Borane with Organolithium Reagents
Authors: Oshiki Toshiyuki , Imamoto Tsuneo 
Published: July 2006

Abstract
The reactions of (Rp)-menthyloxymethyl-phenylphosphine-borane with several organolithium reagents are described. Less sterically hindered reagents such as m-anisyllithium and p-anisyllithium react with the phosphine-borane to afford the corresponding substitution products with high stereochemical integrity with inversion of configuration. On the other hand, o-substituted phenyllithiums lead to products possessing very low optical purities.
New Applications of Crown Ethers. X. 13C NMR Relaxation Times Study of Cation-Binding Behavior of Monoazacrown Ethers and Bis(monoazacrown ether)s
Authors: He Gong-Xin , Imato Toshihiko , Ishibashi Nobuhiko , Shinkai Seiji , Matsuda Tsutomu 
Published: July 2006

Abstract
13C NMR relaxation times (T1s) have been determined for monoazacrown ethers (CA15C5 and CA18C6) and bis(monoazacrown ether)s (BCA15C5, BCA18C6, BOA15C5, and BOA18C6) in the absence and presence of Na+and K+ ions. For the monoazacrown ethers with heptyl side chain and the bis(monoazacrown ether)s with pentamethylene bridge chain marked changes in T1 values are observed upon the complexation, and the changes are dependent on the cation and on the structure of the ligands. The complexation with Na+ ion can give a larger effect on the T1 values for the bis(monoazacrown ether)s of 15- and 18-membered rings, especially on the mobility of the bridging chain carbons, which is indicative of the formation of an intramolecular sandwich complex. On the other hand, the present T1 study again shows the prominent effect of the oxygen in the bridging chain on the complexation of BOA15C5 and BOA18C6. Small differences in T1 values obtained between Na+ complexes and K+ complexes of these two bis(crown ether)s suggest that the complexes take an analogous partial structure for the two cations.
Interaction of α-Helical Glycopeptides with Lipid Bilayer Membrane
Authors: Otoda Kazuya , Kimura Shunsaku , Imanishi Yukio 
Published: July 2006

Abstract
α-Helical polypeptides having a glyco moiety at one end and a fluorescent probe at the other were prepared and investigated on the interaction with a lipid bilayer membrane. A glycopeptide composed of poly(alanine) and maltose was incorporated into the lipid membrane with the glyco moiety exposed to the aqueous phase and the peptide chain buried in membrane above the phase-transition temperature of the lipid membrane. However, below the phase-transition temperature, the glycopeptide induced the aggregation of dimyristoylphosphatidylcholine (DMPC) small unilamellar vesicles (SUV). Another glycopeptide composed of poly(γ-benzyl glutamate) and glucose also induced the aggregation of DMPC SUV, indicating that such the hydrophobic peptide tends to disturb the membrane structure significantly upon binding. The arrangement of the glycopeptide in a membrane was investigated by using a fluorescent probe connected to the end of the peptide chain. The terminal region of the peptide chain was located at the hydrophobic core of lipid membrane. However, the glycopeptide composed of 25 Ala residues had a smaller fraction taking perpendicular orientation to the membrane than that composed of 15 Ala residues. It was therefore considered that a part of the former glycopeptide molecules exits on the membrane surface, forming aggregates.
The Dependence on Alkyl Chain Length of 1H NMR Spectra of Surfactant Micelles with Aromatic Solubilizate
Authors: Hoshino Takashi , Imamura Yoshio 
Published: July 2006

Abstract
The splitting of methylene peaks in the 1H NMR spectra of surfactants of various alkyl length was studied in aqueous solutions solubilized with aromatic compounds, as a function of the carbon numbers of alkyls. In these spectra the methylene signals of long alkyls split into doublets. The location of the solubilization site is discussed while comparing the results with previous 1H NMR observations of long-alkyl-substituted molecules in aromatic solvents.
Hydroalumination and Related Reactions of Phenyl 1-(Trimethylsilyl)propadienyl Sulfide Followed by Quenching with Carbonyl Compounds
Authors: Tanaka Junji , Kanemasa Shuji , Tsuge Otohiko 
Published: July 2006

Abstract
Phenyl 1-(trimethylsilyl)propadienyl sulfide undergoes a hydroalumination with diisobutylaluminum hydride (DIBAH) or lithium butyl(diisobutyl)aluminum hydride (BL-DIBAH). The adduct anion derived from DIBAH is regioselectively trapped with carbonyl compounds at the position α to the phenylthio moiety to give 1,3-dienes as Peterson olefination products; the anion derived from BL-DIBAH is trapped at the position γ to the phenylthio moiety to give 3-buten-1-ols. Silylmetalation and stanylalumination on the same acceptor have been also briefly investigated as equivalent reactions.