bluuebunny/crossref_metadata_2025_split huggingface dataset:
Carbon–Hydrogen Bond Activation by Triruthenium Carbonyl Species during Carbon Monoxide Promoted Elimination of 4,5-Dihydroacenaphthylene from [(μ2 : η1 : η5-C12H10)Ru3H2(CO)7]: Implication of Reaction Intermediates
Authors: Nagashima Hideo , Suzuki Akihiro , Nobata Mitsuharu , Aoki Katsuyuki , Itoh Kenji 
Published: June 2006

Abstract
Oxidative addition of a vinylic C–H bond occurred during the CO-promoted elimination of 4,5-dihydroacenaphthylene (3) from [(μ2 : η1 : η5-C12H10)Ru3H2(CO)7] (2) in CH2Cl2. The product, [(μ3 : η1 : η2 : η2-C12H9)Ru3H(CO)9 ] (4), was isolated and characterized by spectroscopy and crystallography. The carbonylation of a deuterium-labelled complex, [(μ2 : η1 : η5-C12H8D2)Ru3D2(CO)7] (2-d4), under the same conditions as that from 2 to 3 in CH2Cl2 afforded 4,5-dideuterioacenaphthylene (3-d2) and [(μ3 : η1 : η2 : η2-C12H7D2)Ru3H(CO)9] (4-d2). The lack of incorporation of deuterium atoms into the ruthenium hydride in 4-d2 suggested that dissociation of D2 from the triruthenium moiety in 2-d4 induced the oxidative addition of the vinylic C–H bond. Further carbonylation of 4 did not occur under the same conditions as the reaction from 2 to 4, but gave 3 in moderate yields under higher CO pressure (8 atm) at 50—100 °C. These results suggest that 4 was not directly involved in the CO promoted elimination of 3 from 2, but was closely related to the actual intermediates. Possible reaction mechanisms are discussed.
NMR and UV Study of 1,1′-(α,ω-Alkanediyl)bis[thymine] and 1,1′-(α,ω-Alkanediyl)bis[uracil]
Authors: Itahara Toshio 
Published: June 2006

Abstract
Treatment of thymine or uracil with Br(CH2)nBr (n = 3—10) in the presence of t-BuOK gave 1,1′-(α,ω-alkanediyl)bis[thymine] or 1,1′-(α,ω-alkanediyl)bis[uracil] together with 1-(ω-bromoalkyl)thymine or 1-(ω-bromoalkyl)uracil. The structures of these products were determined on the basis of the coupling constants between 5- and 3-positions of uracil ring on the 1H NMR spectra. Molecular aggregation of the thymine and uracil rings of these compounds in aqueous solution was studied on the basis of their 1H NMR and UV spectra. A stacking interaction of the two thymine rings linked by shorter polymethylene chains such as trimethylene and tetramenthylene groups was observed.
Facile Preparation of Vicinal Allylsiloxy- and Vinylsiloxyhaloalkanes and Their Radical Cyclization Reaction
Authors: Shinokubo Hiroshi , Oshima Koichiro , Utimoto Kiitiro 
Published: June 2006

Abstract
Treatment of 2-(allyldimethylsiloxy)-1,1-dibromoalkane, which was easily prepared by an addition of aldehyde to an ethereal solution of (allyldimethylsilyl)dibromomethyllithium, with tributyltin hydride in the presence of catalytic amount of triethylborane afforded 1-oxa-2-silacycloheptane derivative selectively in good yield. On the other hand, cyclization of vinyldimethylsiloxy derivative resulted in a formation of 3-methyl-1-oxa-2-silacyclopentane. An addition of allyldiphenylsilanol to ethyl vinyl ether in the presence of N-iodosuccinimide provided 1-(allyldiphenylsiloxy)-1-ethoxy-2-iodoethane, which was also converted into a seven-membered ring product upon treatment with tributyltin hydride.
A Grignard-Type Addition of Allyl Unit to Carbonyl Compounds Containing a Carboxyl Group by Using BiCl3–Zn(0)–Allyl Bromide
Authors: Wada Makoto , Honna Munekazu , Kuramoto Yoshihiro , Miyoshi Norikazu 
Published: June 2006

Abstract
In the presence of BiCl3–Zn(0), nearly equimolar amounts of allyl bromide reacted with carbonyl compounds containing a carboxyl group to afford the corresponding homoallylic alcohols having a carboxyl group or the intramolecular dehydrated lactones in good yields.
Biscyanines Linked by a 1,8-Naphthylene Skeleton: Models of Polymethine Dye Aggregates
Authors: Katoh Takashi , Ogawa Keizo , Inagaki Yoshio , Okazaki Renji 
Published: June 2006

Abstract
Biscyanines linked by a 1,8-naphthylene skeleton (1), suitable model compounds for a study on polymethine dye aggregates, were prepared. Biscyanines, 1b and 1c, having methoxy and chloro substituents on the benzothiazole nuclei, respectively, were identified to be in syn conformation based upon X-ray crystallographic analysis and NMR spectroscopy. Their absorption maxima were found to be hypsochromically shifted compared to those of the 1-naphthyl substituted monocyanines (2). Only a biscyanine 1e having negatively charged sulfonato groups on the benzothiazole nuclei showed a bathochromic shift and was found to exist as an anti conformer. These spectral shifts were reproduced by the calculations with the INDO/S-CI method and are in agreement with those based upon the molecular exciton theory. The positive shifts of the reduction potentials of 1 compared to those of 2 are explained by the Coulombic and orbital interactions between the two cyanine moieties.
Asymmetric Allylation of Carbonyl Compounds with Tartrate-Modified Chiral Allylic Tin Reagents
Authors: Yamada Koji , Tozawa Takashi , Nishida Minoru , Mukaiyama Teruaki 
Published: June 2006

Abstract
Chiral allylating reagents, readily generated in situ from tin(II) catecholate [SnII(O2C6H4)], allyl halides, chiral dialkyl tartrates, and 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), reacted smoothly with aldehydes or reactive ketones at −78 °C in the presence of a catalytic amount of copper salts to afford the corresponding optically active homoallyl alcohols. Allylation of aromatic aldehydes and pyruvates by the present chiral tin reagents proceeded in high yields (81—99%) with high enantioselectivities (89—94%ee). In addition, both enantiomers of dimethyl citramalate were prepared from the allylation products of benzyl pyruvate.
Imidazolyl-Tailed Tetrakis(pivalamidophenyl)porphyrinatocobalt (II): An Efficient Oxygen Adsorbent Molecule
Authors: Nishide Hiroyuki , Suzuki Ayako , Tsuchida Eishun 
Published: June 2006

Abstract
A meso-tetrakis(α,α,α,α-o-pivalamidophenyl)porphyrinatocobalt(II) derivative bearing covalently-bound imidazole (Scheme 1, CoPim) was synthesized. Oxygen-binding to CoPim was rapid and reversible. The CoPim in the solid state chemically adsorbed oxygen (20 ml O2/g CoPim), which was ca. 40-times greater than the physical adsorption amount. The oxygen-binding lifetime of CoPim was longer than that for the corresponding porphyrinatocobalt(II) with an externally added imidazole. The efficiency of CoPim as an oxygen carrier was demonstrated by oxygen-enrichment from air using a pressure-swing adsorption experiment.
A Newly Designed Adsorbent Prepared from Hydroxyapatite Originating from Cattle-Bones for Chromatographic Separation of Albumin and Lysozyme
Authors: Akazawa Toshiyuki , Kobayashi Masayoshi , Kodaira Kohei 
Published: June 2006

Abstract
Functional spherical particles 5—30 μm in size were prepared by a spray-drying method with ultrasonic dispersion from hydroxyapatite (r-HAp) which was derived from bones of cattle. The liquid chromatographic characteristics for the separation of bovine serum albumin (BSA) and lysozyme from egg white (LSZ) on the r-HAp particles were investigated in comparison with those of stoichiometric hydroxyapatite (s-HAp) derived from reagents. The specific surface area (SAD), the crystallite size (CS), and the microstructure of the HAp’s particles were strongly influenced by the heat-treatment at 273—1073 K (designated by HAp(273—1073)) in a stream of water vapor. In liquid chromatography (LC) analysis with columns packed with the HAp powders, for r-HAp, mixed solutions of 0.5—2.0 mg cm−3 BSA and LSZ were sufficiently eluted using a linear molarity gradient of sodium phosphate buffers at 313 K. The resolutions (RS) of the proteins and the widths for each half of the chromatographic curves (WHB for BSA or WHL for LSZ) were sensitively varied in connection with SAD and CS. The optimal values of the LC operating parameters for all the HAp’s were evaluated as RS of r-HAp(673) and WHB and WHL of r-HAp(873).
Chemical Shift, Chemical Shift Anisotropy, and Spin-Lattice Relaxation Time in 89Y-MAS and -Static NMR of Yttrium Compounds
Authors: Harazono Toshie , Watanabe Tokuko 
Published: June 2006

Abstract
The chemical shift, the range of chemical shift anisotropy, and the spin-lattice relaxation times (T1) in Y2O3, Y3Al5O12, and Y2O2S have been measured by solid state 89Y (nuclear spin 1/2)-MAS and -static NMR. The static NMR data and T1 are reported for the first time. The range of chemical shift anisotropy was 1500—2400 Hz. This range was influenced more by the nature of the atom bound to Y than by the coordination number or the crystallographic symmetry of Y. Very long T1 values were obtained for Y2O2S (6.61 h) and Y2O3 (3.92 h at 24d site and 3.81 h at 8b site). On the other hand, the T1 value (1.10 h) of Y3Al5O12 is much shorter compared with those of Y2O2S and Y2O3. The next-nearest neighboring atom of Y in Y3Al5O12 is identified as Al, which has the nuclear spin 5/2 of 100% natural abundance. The most likely origin of significantly shorter T1 of Y3Al5O12 is a dipole–dipole interaction between 89Y and 27Al.
Cation Diffusion in MGaBr4 (M = Li, Cu, and Ag) Studied by 7Li, 63Cu, and 71Ga NMR, 81Br NQR, and Conductivity
Authors: Tomita Yasumasa , Yamada Koji , Ohki Hiroshi , Okuda Tsutomu 
Published: June 2006

Abstract
Cation diffusion in MGaBr4 (M = Li, Cu) was confirmed by measuring the temperature dependence of the 7Li and 63Cu NMR linewidths. The activation energies for the cation diffusion were determined to be 36 and 44 kJ mol−1 for LiGaBr4 and CuGaBr4, respectively. The activation energy for the reorientation of the GaBr4− anion in CuGaBr4 was evaluated to be 62 kJ mol−1 from 71Ga NMR. The cation diffusion was also confirmed for MGaBr4 (M = Cu, Ag) by observing a modulation effect on the 81Br NQR T1. As expected from the modulation effect of NQR, the ionic conductivity of AgGaBr4 was one order higher than that of CuGaBr4.
Non-Bornian Ion Solvation Energy. An Approach from Redox Potentials of Heteropoly Oxometalate Anions
Authors: Osakai Toshiyuki , Maeda Kohji , Ebina Kuniyoshi , Hayamizu Hiroko , Hoshino Motohiko , Muto Kazuhiro , Himeno Sadayuki 
Published: June 2006

Abstract
The first and second redox potentials ( and ) of Keggin-type heteropolytungstate anions (α-[PW12O40]3− and α-[SiW12O40]4−) have been determined in various solvents by means of cyclic voltammetry. The difference () between and , being theoretically associated with the solvation energies of the polyanions, does not correlate with the permittivity of the solvent, in conflict with an expectation based on the Born-type electrostatic solvation model. In contrast, has been found to show some definite correlations with such empirical solvent parameters as acceptor numbers. This shows that the short-range interactions (i.e., donor–acceptor effects or hydrogen bonds) between the heteropolyanion and its primary solvents play the most significant role in the solvation of the heteropolyanions. We have thus proposed a new analytical equation for evaluating the short-range ion–solvent interaction energy.
Determination of Consecutive Formation Constants of Complex Ions from Ion-Transfer Voltammetric Data
Authors: Katano Hajime , Senda Mitsugi 
Published: June 2006

Abstract
The half-wave potentials of the voltammetric waves of facilitated transfer of Pb2+ ion by 1,4,7,10,13,16-hexathiacyclooctadecane across the nitrobenzene/water interface have been measured as a function of the concentration of free CH3COO− ion in aqueous phase. Using the equation of reversible half-wave ion-transfer potential, the formal formation constants of 1 : 1, 1 : 2, and 1 : 3 Pb2+–CH3COO− complexes in the aqueous medium have been determined to be 102.3 M−1, 103.0 M−2, and 104.0 M−3, respectively. A polynomial regression method for the determination of the formation constants from voltammetric data is presented. Ion-transfer voltammetry at the liquid/liquid interface can be applied advantageously to the determination of consecutive formation constants of metal complexes with a ligand in aqueous media as well as those with an ionophore in organic media.
Novel Regioselective Ester Hydrolysis by Pig-Liver Esterase
Authors: Basak Amit , Bhattacharya Gautam , Palit Sunanda K 
Published: June 2006

Abstract
Pig-liver esterase, which catalyzed the hydrolysis of substrates containing both saturated and α,β-unsaturated/cyclopropanecarboxylic esters (methyl and ethyl), was studied. An exclusive hydrolysis of the saturated esters was observed. Kinetic experiments revealed that the presence of deactivated carbonyl in the unsaturated/cyclopropanecarboxylic esters and their weaker bindings are both responsible for the observed specificity. The relative binding abilities of the substrates have been explained in light of Jones active-site model. The regioselectivity has been exploited in the synthesis of intermediates for the thromboxane synthetase inhibitor.
Oxidative Generation of 1-Nitroalkyl Radicals and Their Addition Reaction to Olefins
Authors: Arai Noriyoshi , Narasaka Koichi 
Published: June 2006

Abstract
1-Nitroalkyl radicals are generated by oxidation of potassium salt of 1-aci-nitroalkanes with ammonium hexanitratocerate(IV). When the oxidation is carried out in the presence of electron-rich olefins, such as silyl enol ethers, intermolecular addition of the radicals onto the olefins proceeds to afford β-nitro ketones, which are further converted to α,β-unsaturated ketones in high yield. Stereoselective construction of fused ring systems is achieved by intramolecular addition of 1-nitroalkyl radicals.
An Efficient Synthesis of Racemic Necine Bases from a Common Intermediate
Authors: Niwa Haruki , Kuroda Akio , Sakata Tomoyo , Yamada Kiyoyuki 
Published: June 2006

Abstract
Necine bases of pyrrolizidine alkaloids, turneforcidine, hastanecine, and platynecine are synthesized from ethyl 1-hydroxy-2,3,5,6-tetrahydro-1H-pyrrolizine-7-carboxylate in racemic form.
Baeyer–Villiger Oxidation over HZSM-5 Type Zeolites
Authors: Wang Zheng Bao , Mizusaki Tooru , Sano Tsuneji , Kawakami Yusuke 
Published: June 2006

Abstract
The catalytic performance of various protonated zeolites for the Baeyer–Villiger (BV) oxidation of cyclopentanone to δ-valerolactone with aqueous H2O2 as an oxidant was investigated. It was found that highly siliceous HZSM-5 zeolites are active for the oxidation reaction, and that the oxidation reaction is promoted by the Brønsted acid sites in the intracrystallines of zeolites, not on the external surface. The influences of the reaction variables (solvent, temperature, and time) and the crystal size of zeolite on the conversion of cyclopentanone and the yield of δ-valerolactone were also studied.
Theoretical Prediction of Intracluster Reactions of B+(H2O)2 and B+(H2O)3: Hybrid Procedure of Ab Initio MO Calculations and Monte Carlo Samplings
Authors: Watanabe Hidekazu , Asada Toshio , Iwata Suehiro 
Published: June 2006

Abstract
A recently developed hybrid procedure of ab initio molecular orbital (MO) calculations and Monte Calro (MC) samplings is applied to investigate the intracluster reactions of B+(H2O)n (n = 2 and 3). In this procedure we do not assume the potential energy functions during MC samplings. At every step the ab initio MO method is directly used to evaluate the electronic energy. The procedure makes it possible to deal with the intra-cluster reaction involving any rearrangement of atoms such as isomerization and dissociation. The many-body effects on the energy are taken into account within the approximation used in the MO calculation. During the MC samplings at room temperature, the B+(H2O)2 cluster undergoes a series of isomerization reactions, and eventually forms the most stable isomer, sp2 type of trans HBOH+(H2O). For B+(H2O)3, the reactions turn out to be more complicated, and a few times simulations suggest that there are several reaction products as well as intermediates in the reactions. The MO-MC procedure is proved to be a powerful tool to search for many isomers, reaction intermediates, and the products as well as the transition state structures between them although it is still very time-consuming.
Direct Calculation of CH4–He Interaction Potential from the Extended Principle of Corresponding States
Authors: Ghatee Mohammad Hadi , Papari Mohammad Mehdi , Boushehri Ali 
Published: June 2006

Abstract
The interaction potential energy between CH4 and He has been determined from the extended law of corresponding states for viscosity using the inversion technique. Lennard–Jones (12-6) and BBMS potential functions have been checked as the initial model potentials required by the technique. The resulting potential energy from L–J potential is in excellent agreement with the one obtained from crossed molecular beam experimental results. The interaction potential energies from inversion reproduce the viscosity within 1%, the binary diffusion coefficient within 5%, and the thermal diffusion within 25%.
Crystal Structure and Physical Properties of (BEDT-TTF)2BF4Sol0.5 (Sol = 1,1,2-Trichloroethane, 1,2-Dibromoethane, 1,2-Dichroloethane)
Authors: Miyazaki Akira , Ichikawa Isao , Enoki Toshiaki , Saito Gunzi 
Published: June 2006

Abstract
The crystal structures and phase transition nature of (BEDT-TTF)2BF4Sol0.5 (Sol = TCE, DBE, and DCE) are investigated by means of X-ray diffraction, electrical conductivity, ESR, and magnetic susceptibility measurements. As the size of the neutral molecules become smaller (TCE &gt; DBE &gt; DCE), the metal-insulator transition temperature rises (60 K &lt; 100 K &lt; 110 K), showing that their transitions are governed mainly by the structural degrees of freedom. For the DBE and DCE salts, these transitions are simple metal-insulator transitions, whereas the transition of the TCE salt occurs only when the sample is cooled slowly, and the Fermi surfaces survive in the resulting low-temperature phase. For this salt, the anomaly of the interplanar resistivity appears at ca. 160 K for the slow cooling process, and the difference of the ESR line width between the slow and rapid cooling processes is also observed below this temperature. These phenomena are due to the disorder enhanced by the generation of the in-plane superlattice.
Photoinduced Picosecond Bimolecular Reaction between trans-Stilbene and Carbon Tetrachloride
Authors: Iwata Koichi , Hamaguchi Hiro-o 
Published: June 2006

Abstract
A new photochemical reaction has been found between trans-stilbene and carbon tetrachloride. In carbon tetrachloride, the first excited singlet (S1) state of trans-stilbene decays with a time constant of 3.1 ± 0.2 ps, a factor of ten or more faster than in alcohols and hydrocarbons. The mechanism of this anomalous lifetime shortening has been studied by using four time-resolved spectroscopies: sub-microsecond infrared, picosecond Raman, sub-picosecond visible absorption, and picosecond fluorescence. After photoexcitation to the S1 state, a bimolecular reaction occurs between trans-stilbene and the solvent carbon tetrachloride to form a stilbene-Cl adduct and the trichloromethyl (·CCl3) radical. Then, the stilbene-Cl adduct and the ·CCl3 radical are likely to react further in about 100 μs, following second-order reaction kinetics. The newly found photochemical reaction between trans-stilbene and carbon tetrachloride can serve well as a prototype for studying the microscopic mechanism of bimolecular reactions in solution.
Enzymatic Synthesis of 4-Methylumbelliferyl Glycosides of Trisaccharide and Core Tetrasaccharide, Gal(β1-3)Gal(β1-4)Xyl and GlcA(β1-3)Gal(β1-3)Gal(β1-4)Xyl, Corresponding to the Linkage Region of Proteoglycans
Authors: Yasukochi Takashi , Fukase Koichi , Suda Yasuo , Takagaki Keiichi , Endo Masahiko , Kusumoto Shoichi 
Published: June 2006

Abstract
Fluorescence labeled trisaccharide, Gal(β1-3)Gal(β1-4)Xyl(β)–MU [MU = 4-methyl-2-oxo-2H-chromen-7-yl (4-methylumbelliferyl)], and tetrasaccharide, GlcA(β1-3)Gal(β1-3)Gal(β1-4)Xyl(β)–MU, corresponding to the linkage region between glycosaminoglycans and core proteins in proteoglycans were synthesized from Xyl–MU by stepwise enzymatic transglycosidation using β-galactosidase (Escherichia coli) and β-glucuronidase (bovine liver). Introduction of the second galactosyl residue at the 3′-position of Gal–Xyl–MU was achieved by minimal protection of the disaccharide intermediate whose reactive primary hydroxy function was selectively protected with an acetyl group by using lipase catalyzed transacetylation. Regioselective β-glucuronylation was effected by the high substrate specificity of the β-glucuronidase without any protection of the glycosyl acceptor.
Kinetic Study of the Shape Change of Human Erythrocyte Induced by Sodium Alkyl Sulfates
Authors: Inoue Katsuaki , Sekido Takako , Sano Takayuki 
Published: June 2006

Abstract
In order to clarify the mechanism of the shape change of human erythrocytes induced by anionic surfactants, kinetic experiments were performed using the stopped-flow technique and the conventional spectroscopic method. In the time range from 0.1 s to a few dozen minutes, four kinetic processes were observed. In the dead time of the stopped-flow apparatus (within 10 milli seconds), a decrease in the intensity of the transmitting light was observed. Based on an analysis of the dependence of the relaxation time of each process on the surfactant concentration for various reaction schemes, we propose a most plausible reaction model that includes four kinds of binding processes of the surfactant and three intramolecular processes. In the present paper, based on this model, we discuss the detailed mechanism of the shape change of the erythrocytes.
Unusual Stabilities and Reactivities of Tris- and Bis(2,4,6-trimethoxyphenyl)carbenium Salts
Authors: Wada Masanori , Konishi Hideki , Kirishima Katsuhiko , Takeuchi Hiroshi , Natsume Satoko , Erabi Tatsuo 
Published: June 2006

Abstract
2,4,6-Trimethoxyphenyllithium, Φ′Li[Φ′ = 2,4,6-(MeO)3C6H2], reacted with diphenyl carbonate and with ethyl formate to give tris(2,4,6-trimethoxyphenyl)methanol, Φ′3COH (1), and bis(2,4,6-trimethoxyphenyl)methanol, Φ′2CHOH (2), respectively. Compound 1 reacted with a slight excess of perchloric acid in 2-propanol to give very dark-purple crystals of the triarylcarbenium salt, [Φ′3C]X (3, X = ClO4), which were inert even in hot ethanol. However, a treatment of 3 (X = Cl), prepared in situ in 1 M (1 M = 1 mol dm−3) hydrochloric acid, with 1 M sodium hydroxide resulted to give 4-bis(2,4,6-trimethoxyphenyl)methylene-3,5-dimethoxy-2,5-cyclohexadienone. Compound 2 also reacted with a slight excess of perchloric acid in methanol to give dark-red crystals of the diarylcarbenium salt, [Φ′2CH]X (5, X = ClO4). Compound 5 was considerably inert even in hot methanol, but was easily reduced in primary and secondary alcohols to give bis(2,4,6-trimethoxyphenyl)methane, Φ′2CH2. Measurements of the half-lives of 5 in these alcohols showed that 5 was more labile in secondary alcohols, such as 2-propanol and 2-butanol, than in primary alcohols. When a suspension of 5 (X = Cl), prepared in situ in 1 M hydrochloric acid, was heated, tris(2,4,6-trimethoxyphenyl)methane, Φ′3CH (7), was obtained. Analogous reactions to give 7 were observed in methanol containing a slight excess of hydrochloric acid or nitric acid in place of perchloric acid. The possible paths of these reactions are discussed.