bluuebunny/crossref_metadata_2025_split huggingface dataset:
Kinetics and Mechanism of Anation of Pentaammineaquarhodium(III) Ion by Malonate in Weakly Acidic Media
Authors: Chatterjee Chinmay , Bali Aya Singh 
Published: July 2006

Abstract
Anation of pentaammineaquarhodium(III) ion by malonic acid, hydrogenmalonate, and malonate ions to form the hitherto unknown pentaamminemalonatorhodium(III) complex has been studied as a function of [H+] for the acidity range 1.4≤ pH ≤5.0, [total malonate], 0.3 mol dm−3 in the temperature range of 60 to 80 °C and at ionic strength 1.0 mol dm−3 adjusted with sodium perchlorate. Ion pairing is not significant between the complex and malonic acid but kinetically identifiable with hydrogenmalonate and malonate ions. Ion pair association constants for the hydrogenmalonate (Q1) and malonate ion (Q2) at 60 °C are 1.8 and 7.5 mol−1 dm3 respectively. The values of the rate constants at 60 °C for anation by malonic acid, hydrogenmalonate, and malonate ions are k0=3.04±0.2×10−5 mol−1 dm3 s−1, k1=1.73±0.2×10−4 s−1, and k2=3.46±0.4×10−4 s−1. The activation parameters, ΔH\eweq and ΔS\eweq corresponding to anation rate constants, k0, k1, and k2 are reported and the results discussed with reference to analogous reactions of Rh(III) and Co(III).
A 15N NMR Study of the Tautomeric Equilibria of Some 5-Substituted Tetrazoles
Authors: Bojarska-Olejnik Elzbieta , Stefaniak Lech , Witanowski Michal , Webb Graham A 
Published: July 2006

Abstract
15N NMR shielding data are presented for some 5-tetrazolones and some 5-tetrazolethiones. CNDO/S-SOS nitrogen shielding calculations are also performed for these compounds. The results obtained show that the compounds studied exist almost entirely in the oxo and thioxo forms, rather than the hydroxy or mercapto forms respectively, in DMSO solution.
The Structure of Bis(μ-thiocyanato)-bis[tris(benzylamine)(thiocyanato)nickel(II)], [Ni(SCN)2(C6H5CH2NH2)3]2
Authors: Taniguchi Masahiro , Ouchi Akira 
Published: July 2006

Abstract
The crystal and molecular structure of the title complex was determined by means of a single-crystal X-ray diffraction method. A crystal of Ni2C46H54N10S4, F. W. 992.67, is triclinic with a space group P\bar1, a=13.259(4), b=15.627(5), c=6.5150(16) Å, α=90.60(3), β=93.64(2), γ=112.601(19)°, U=1242.9(6) Å3, Z=1, Dm=1.32(3), Dx=1.33 Mg m−3, and μ(Mo Kα)=9.60 cm−1. The central metal atom is hexa-coordinated, being ligated with three benzylamine and two thiocyanato (SCN) nitrogen atoms as well as one SCN sulfur atom. Two metal atoms are bridged by two SCN ions; however, the Ni-S bond length is 2.639(3) Å, which is a little longer than the sum of the Shannon’s ionic radii. The distance Ni···Ni is 5.717(3) Å and the dimeric complexes are discrete in a crystal.
A Convenient Method for Conversion of Allylic Chlorides to α,β-Unsaturated Aldehydes
Authors: Suzuki Shigeaki , Onishi Takashi , Fujita Yoshiji , Misawa Hiromitsu , Otera Junzo 
Published: July 2006

Abstract
Tertiary amine N-oxides were found to be effective for converting allylic chlorides to α,β-unsaturated aldehydes.
Gas-Chromatographic Measurements of Atmospheric Sulfur Hexafluoride
Authors: Hirota Michio , Muramatsu Hisafumi 
Published: July 2006

Abstract
From air samplings on aircraft in February and December 1982 and in February 1983, and from gas-chrornatographic measurements, the background volume mixing ratio of sulfur hexafluoride(SF6) over Japan was found to be about (0.72±0.13) ppt, where ppt=10−12. Since the first observation by Lovelock in 1970 (0.03 ppt), SF6 seems to have been increasing steadily.
Synthesis of Phosphirane Oxide Derivatives Promoted by Introduced Phenylsulfinyl Groups and Their Pummerer Reaction
Authors: Oshikawa Tatsuo , Yamashita Mitsuji 
Published: July 2006

Abstract
Phosphirane oxide derivatives were first successfully synthesized in good yield under mild conditions wherein carbon–carbon bond formation was promoted by two phenylsulfinyl groups on the α and α′ carbons of the phosphorus atom. A structure determination of the formed phosphirane oxide derivatives as well as the stereochemistry of the Pummerer reaction product revealed a trans geometry for the phosphirane oxide.
Chromotropisms of Imidazole Derivatives. III. Crystal Structure of 4,5-Bis(4-methoxyphenyl)-2-(4-nitrophenyl)-1H-imidazole
Authors: Inouye Yoshinobu , Sakaino Yoshiko 
Published: July 2006

Abstract
The molecular and crystal structure of the title compound was determined by the single-crystal X-ray analysis. The crystal is orthorhombic with a space group Pbca, a=15.161 (9), b=25.805 (5), c=9.948 (1) Å, and Z=8. The 4-nitrophenyl ring is nearly on a same plane with the imidazole ring, while the other two benzene rings make angles of 26.5° and 47.7°.
A Convenient Synthesis of N-Substituted Formamidines by Desulfurization of the Corresponding Thioureas
Authors: Kashima Choji , Shimizu Masao , Eto Takeshi , Omote Yoshimori 
Published: July 2006

Abstract
N,N′-Di- and N,N,N′-trisubstituted thioureas were easily desulfurized by Raney nickel to yield the corresponding formamidines, while N-monosubstituted thioureas gave N,N′-disubstituted formamidines.
Asymmetric Reduction of Aromatic Ketone in a Continuous Flow System
Authors: Itsuno Shinichi , Ito Koichi , Maruyama Toshihiro , Kanda Naoki , Hirao Akira , Nakahama Seiichi 
Published: July 2006

Abstract
When THF–borane (1/1) and aromatic ketone were supplied continuously to the column containing polymer-supported (S)-(−)-2-amino-3-(p-hydroxyphenyl)-1,1-diphenyl-1-propanol, the chiral product, secondary benzylic alcohol, could be obtained successfully (&gt;90% ee). Large quantities of highly optically pure alcohol could be produced by the continuous flow system by the use of only a small amount of polymeric auxiliary.
Electrocatalysis of the Heat-Treated (5,10,15,20-Tetraphenylporphyrinato)manganese(III) Halides for Cathodic Reduction of Oxygen
Authors: Ikeda Osamu , Kojima Toyosei , Tamura Hideo 
Published: July 2006

Abstract
Electrocatalysis of the heat-treated (5,10,15,20-tetraphenylporphyrinato)manganese(III) halides (MnIII(TPP)X, X:F−, Cl−, Br−, I−) for the O2 reduction in an alkaline solution has been studied by rotating ring-disc electrode technique, and the result was correlated with properties of the heat-treated MnIII(TPP)X, such as magnetic moment and electrical resistivity. The axial ligand X showed noticeable effect on the catalytic activity. The catalytic activity estimated from the overpotential changed in the following order: F−&gt;Cl−&gt;Br−&gt;I−. The catalytic activity for reducing oxygen to OH− was low, but the same order of activity as the above applies. The order was interpreted by the σ-donating ability of halide ion X to dz2 orbital. The active site of the MnIII(TPP)X heat-treated at 700 °C for O2 reduction is ascribed to the metal ion, coordinated to slightly degraded or perfect N4 center, but not degradation products of the relevant compounds.
Stopped-Flow Kinetic Study of the Complex Formation between Pyridoxal 5′-Phosphate and Bovine Serum Albumin
Authors: Murakami Kiyofumi , Kubota Yukio , Fujisaki Yasuo , Sano Takayuki 
Published: July 2006

Abstract
The complex formation between pyridoxal 5′-phosphate (PLP) and bovine serum albumin at pH=7.0 and 25 °C was characterized by four relaxation processes. The dependence of the reciprocal relaxation times upon reactant concentrations was found to be consistent with a mechanism in which a rapid bimolecular binding step is followed by three sequential isomerization steps. The eight rate constants for this mechanism were determined and then combined to calculate an overall equilibrium constant which is in agreement with the literature value. Absorption spectra of the complexes formed by the two faster steps were determined from absorbance changes associated with them; the spectrum corresponding to the first complex has two bands at 330 nm and 360 nm and an additional 410 nm band, while the spectrum corresponding to the second complex has a large single band at 375 nm. Comparing these spectra with those reported for other PLP-enzyme systems, we speculate that four steps in the proposed mechanism may correspond to the rapid formation of a carbinolamine, which is in very rapid equilibrium with a Schiff base form, followed by the deprotonation of the ring nitrogen, the formation of an ionic hydrogen-bonded Schiff base, and the final formation of a nonionic hydrogen-bonded Schiff base.
High-Spin(5T2) \ightleftharpoons Low-Spin(1A1) Transition in Mixed Ligand Complex [Fe(2,2′-bipyridine)(1,10-phenanthroline)(NCS)2]
Authors: Inoue Hidenari , Nakajima Hiroko , Takahashi Takeshi , Uchida Hiroshi , Shirai Tsuneo , Fluck Ekkehard 
Published: July 2006

Abstract
A new type of the mixed ligand complex [Fe(bpy)(phen)(NCS)2] (bpy=2,2′-bipyridine and phen=1,10-phenanthroline) has been prepared by two different methods. The influence of the mixed ligand coordination of bpy and phen to a central iron(II) ion is studied by measurements of the temperature variation of magnetic moments and Mössbauer parameters. It has been demonstrated that the mixed coordination tends to make the 5T2(high-spin) \ightleftharpoons 1A1(low-spin) transition more gradual. The spin-crossover transition temperature depends on the electronic property as well as the structure of the ligand coordinated to the central iron(II) ion.
Structures of Yadanziosides K, M, N, and O, New Quassinoid Glycosides from Brucea javanica (L.) Merr
Authors: Sakaki Toshiro , Yoshimura Shin , Tsuyuki Takahiko , Takahashi Takeyoshi , Honda Tadashi , Nakanishi Toshihiro 
Published: July 2006

Abstract
Four new bitter quassinoid glycosides, yadanziosides K, M, N, and O were isolated from Brucea javanica (L.) Merr and their structures were determined by spectral measurement and chemical means. The aglycone of yadanzioside O was found to exhibit a significant antitumor activity against the murine P388 lymphocytic leukemia and this aglycone could be prepared from brusatol.
Syntheses of New Optically Active Organosilanes and Their Applications for the Optical-Purity-Determining Agents
Authors: Terunuma Daiyo , Kato Masato , Kamei Masanao , Uchida Hidekatsu , Ueno Satoshi , Nohira Hiroyuki 
Published: July 2006

Abstract
New optically active organosilicon compounds such as (benzylmethylphenylsilyl)acetic acid (1) and (ethylmethylphenylsilyl)acetic acid (2) were synthesized. Application of these acids as the optical purity determining agents for chiral amines and alcohols were successfully carried out. In addition, it was also revealed that optically active (benzylmethylphenylsilyl)methylamine (3) and [benzylmethyl(o-tolyl)silyl]methylamine (4) are able to be used as the optical purity determining agents for chiral carboxylic acids.
Effect of CH2Br2-Addition upon Direct Oxidative Dehydrogenation of Butane into 1,3-Butadiene over Fe–Sb–O Composite Catalyst
Authors: Saitoh Hitoshi , Satoh Satoshi , Sodesawa Toshiaki , Nozaki Fumio 
Published: July 2006

Abstract
Effect of CH2Br2-addition upon direct oxidative dehydrogenation of butane into 1,3-butadiene has been investigated in a conventional flow apparatus. The activity and selectivity of Fe–Sb–O catalyst were much improved by the addition of CH2Br2 to butane in the mole ratio, CH2Br2/n-C4H10, of 0.03 to 0.10 at temperatures near 450 °C.
Preparation of Polymer-Protected Colloidal Dispersions of Copper
Authors: Hirai Hidefumi , Wakabayashi Hidehiko , Komiyama Makoto 
Published: July 2006

Abstract
Colloidal copper dispersions are prepared by reducing copper(II) ions in water with sodium tetrahydroborate or hydrazine in the presence of various protective polymers. The polymers are poly(N-vinyl-2-pyrrolidone), poly(vinyl alcohol), poly(methyl vinyl ether), poly(potassium vinyl sulfate), dextrin, amylopectin, methylamylopectin, methylcellulose, ethylcellulose, and (2-hydroxyethyl)cellulose. The dispersions are black, reddish dark brown, or reddish brown homogeneous solutions, and are stable under nitrogen at room temperature for more than three months. Electron diffraction experiments indicate that copper atoms in the colloidal particles are arranged in an ordered way, which is almost identical with that in a crystal of bulk copper metal. At the charged molar ratio 40 of the monomeric residue of the protective polymer to copper(II) ion, the average diameters of the copper particles, prepared by use of sodium tetrahydroborate, range from 50 to 150 Å, depending on the polymer used. With the use of poly(N-vinyl-2-pyrrolidone) as protective polymer, the size of the copper particles monotonously increases with increase in the degree of polymerization of the polymer and also with decrease in the amount of the polymer.
Determination of a Small Amount of a Biological Constituent by Use of Chemiluminescence. IX. Effect of a Ligand on a Peak Shape
Authors: Hara Tadashi , Arai Akihiro , Iharada Takeshi 
Published: July 2006

Abstract
The chemiluminescence intensity of a 1,10-phenanthroline-hydrogen peroxide system was systematically examined in the presence of various types of copper(II) chelate-forming ligands. There was a good relation between the peak shape on a recorder chart and the types of ligands; they could be classified into four groups as follows: A) Both bidentate and tridentate ligands gave positive and negative peaks. B) The ligand having more than four donor atoms, as in a quadridentate ligand or protein, gave a single negative peak. C) A liberated porphine ring gave a single sharp negative peak. D) Some metal organic compounds such as vitamine B-12 and ferritin gave broader positive and negative peaks in comparison with those in A). These unique peak shapes were applicable to the estimation of the type of ligand. α-Fetoprotein as a tumor marker could be also easily detected with a detection limit of 250 pg and with a typical coefficient of variation of 3.8%.
Potentiometric Study of Copper(II) Complexes with β-Diketone in Micellar Solution Using a Copper(II) Ion-Selective Electrode
Authors: Aihara Makoto , Sugi Kyoko , Goya Yumiko 
Published: July 2006

Abstract
The distribution of copper(II) complexes with thenoyltrifluoroacetone, pivaloyltrifluoroacetone and 3-phenyl-2,4-pentanedione between micellar and bulk phases in aqueous solution containing nonionic surfactant was investigated by potentiometry with a copper(II) ion-selective electrode. The apparent equilibrium constants for the copper(II) complexes in micellar solution were determined.
Dehydrooligopeptides. VI. Facile Transformation of α-Phosphoranylideneamino-α-alkenoates to Δ2-Dehydrodipeptide Derivatives
Authors: Yonezawa Yasuchika , Kisuno Atsushi , Shin Chung-gi 
Published: July 2006

Abstract
Arbusov reaction of alkyl α-phosphoranylideneamino-α-alkenoates with several halides gave the corresponding α-phosphinylamino-α-alkenoates and Δ2-dehydrodipeptide derivatives.
A Convenient Synthesis of Cholesta-1,5,7-trien-3β-ol
Authors: Tachibana Yoji 
Published: July 2006

Abstract
Cholesta-4,6-dien-3β-ol (4) was obtained selectively by the dehydrobromination of 7-bromocholesterol with a base in the presence of a catalytic amount of tetrabutylammonium bromide. The oxidation of 4 with 2,3-dichloro-5,6-dicyano-p-benzoquinone gave cholesta-1,4,6-trien-3-one (7). Treatment of 7 with isopropenyl acetate under acidic conditions afforded 3-acetoxy-1,3,5,7-cholestatetraene, which was reduced with calcium borohydride to yield cholesta-1,5,7-trien-3β-ol (2).
The Dynamical Structure of Normal Alcohols in Their Liquids as Determined by the Viscosity and Self-Diffusion Measurements
Authors: Iwahashi Makio , Ohbu Yoko , Kato Tadashi , Suzuki Yumi , Yamauchi Kazuhiro , Yamaguchi Yoshimi , Muramatsu Mitsuo 
Published: July 2006

Abstract
The conformation of molecules of normal alcohols in their pure liquids is estimated through an analysis of their self-diffusion coefficients, viscosities, and molar volumes. The conformation of molecules of shorter chained alcohols (C1–C3) is approximately of sphere, while that for longer chains is of rodlike shape. In pure liquids of alcohols, rigid rod molecules whose free rotating motions along their rod axes seem to be restricted, are randomly orientated and entangled with one another. The self-diffusion of long-chain alcohols involves a longitudinal translation of rodlike molecules. Large apparent hydrodynamic radii suggest that the transport unit of normal alcohol is a dimer (on an average) of alcohol molecules.
Relations between Diatomic Constants and the Features of the Potential Energy Surfaces
Authors: Tanaka Noboru 
Published: July 2006

Abstract
The semiempirical method is used to calculate potential energy surfaces. The linear H3 and rectangular H4 systems have been chosen as standard surfaces in order to compare the surface features. Relationships between diatomic constants and topological features along a minimum energy path, and the height and location of the barrier, are demonstrated.
Structural Effects in the Reactions of Diazoalkanes with 2,3-Dichloro-5,6-dicyanobenzoquinone
Authors: Oshima Takumi , Nagai Toshikazu 
Published: July 2006

Abstract
2,3-Dichloro-5,6-dicyanobenzoquinone (DDQ) reacted with diazoethane to give stereoisomeric bicyclic diones (3, isomer ratio=3.4) arising from dipolar addition to the C=C bond of DDQ. DDQ reacted with phenyldiazomethane to afford also stereoisomeric bicyclic diones (7) in the ratio of 5:1, together with stilbenes (8). On the other hand, DDQ gave the (ethenyloxy)benzene derivative (14) with 1-phenyldiazoethane. The formation of 8 and 14 was interpreted by considering the participation of 1:1 betaines resulting from addition to the C=O bond. The added methanol captures the betaines, thus giving rise to dimethyl acetals of benzaldehyde and acetophenone, along with 2,3-dichloro-5,6-dicyanohydroquinone. These reactivities of DDQ were discussed in comparison with those of chloranil.
Synthetic Studies of Diels–Alder Adduct of Furan. Formal Total Synthesis of (±)-Avenaciolide
Authors: Kotsuki Hiyoshizo , Ohnishi Hiroyuki , Akitomo Yasuhiro , Ochi Masamitsu 
Published: July 2006

Abstract
The endo-Diels–Alder adduct of furan with methyl acrylate was transformed into a bis-γ-lactone derivative which is a well-known precursor for the synthesis of (±)-avenaciolide. The route involves 13 steps and the overall yield was 17.9%.
Syntheses of (−)-8-epi-Swainsonine and (−)-1,8-Di-epi-swainsonine, Stereoisomers of Physiologically Interesting Indolizidine Alkaloid, Swainsonine
Authors: Tadano Kin-ichi , Iimura Youichi , Hotta Yukinori , Fukabori Chiyoko , Suami Tetsuo 
Published: July 2006

Abstract
Two stereoisomers of the indolizidine alkaloid swainsonine, (−)-8-epi-swainsonine (2) and (−)-1,8-di-epi-swainsonine (3), have been synthesized from the known methyl 3-acetamido-2-O-acetyl-4,6-O-benzylidene-3-deoxy-α-d-glucopyranoside and methyl 3-acetamido-2-O-acetyl-3-deoxy-4,6-di-O-mesyl-α-d-glucopyranoside (14), respectively. The key pyrrolidine ring formation was achieved by intramolecular cyclization of a 6-O-tosyl derivative or a di-O-mesyl derivative 14 efficiently. The α-mannosidase inhibitory activity of the synthetic 2 and 3 was also evaluated.
Chemical Reactivities of Coordinatively Unsaturated Hydridotris(phosphonite)cobalt(I) Species Photogenerated towards Allylic and Related Compounds
Authors: Onishi Masayoshi , Oishi Shigero , Sakaguchi Mitoshi , Takaki Isato , Hiraki Katsuma 
Published: July 2006

Abstract
Pyrex-filtered photoirradiation with a high-pressure Hg lamp was performed for a thermally inert hydridocobalt(I) CoH[PPh(OEt)2]4 in the presence of some allylic compounds. Allyl benzoate and allyl phenyl ether showed the cleavage of allylic-O bonds to give propene in a stoichiometric quantity to the complex charged. Photoassisted catalytic double-bond migration occurred for N-allylacetamide, N,N-diethylallylamine, and allylbenzene to afford the respective (E)- and (Z)-1-propenyl derivatives with kinetically controlled E, Z compositions, and the fractions of Z isomers at the initial stage of the reaction proceeding were near 79, 30, and 20%, respectively. Laser flash photolysis study revealed that the double-bond migration was initiated by the coordination of the substrates through C=C double bond rather than nitrogen or oxygen donor-atom to the coordinatively unsaturated species “CoH[PPh(OEt)2]3” photogenerated.
Titanium Determination under High-Sensitivity Conditions with 2-(5-Chloro-2-pyridylazo)-5-dimethylaminophenol. I
Authors: Marini Héctor Jose , Antón Rosa Isabel , Boeris Maria Susana , Olsina Roberto Antonio 
Published: July 2006

Abstract
The optimum working conditions for the complexing reactions between Ti(IV) and 2-(5-chloro-2-pyridylazo)-5-dimethylaminophenol (5.ClDMPAP) in aqueous alcoholic solutions were studied. When an ethanol solution of 5.ClDMPAP is added to a Ti(IV) aqueous solution, complex species, whose spectral and stoichiometric characteristics depend on pH, develop rapidly. The complex selected for the analytical work forms between pH 4.7 and 5.8 and has a 3:1 ligand-metal molar ratio. The complex fulfils Beer’s law up to a Ti(IV) concentration of 0.7 ppm, working at λmax=580 nm. The optimum concentration range (Ringbom) was between 0.05 and 0.7 ppm of Ti(IV). The molar absorptivity at λmax=580 nm and Sandell index are 4.39×104 dm3 mol−1 cm−1 and 0.0011 μg cm−2, respectively. An absorptiometric method to determine Ti(IV) was developed and the proper ways to reduce interferences produced by some anions and cations are described. The method developed was applied to Ti(IV) determination in optical glass and ceramic materials.
Temperature Dependences of 69Ga and 81Br NQR Frequencies in [R4N]2Ga2Br6 (R=CH3 and C2H5)
Authors: Ishihara Hideta , Yamada Koji , Okuda Tsutomu 
Published: July 2006

Abstract
Temperature dependences of 69Ga and 81Br NQR frequencies showed that phase transitions take place at 98 and 137 K in [(CH3)4N]2Ga2Br6 and that the C3 reorientation of the GaBr3 group occurs in [(C2H5)4N]2Ga2Br6 around room temperature.
The Revised Structure of a Dihydrobenzofuran Derivative Isolated from Lasiolaena morii
Authors: Yamaguchi Seiji , Saitoh Akihito , Kawase Yoshiyuki 
Published: July 2006

Abstract
Two isopropenyldihydrobenzofuran derivatives are synthesized. By the comparison of 1H NMR spectra, the proposed structure of a natural dihydrobenzofuran is revised to 4-acetyl-2-isopropenyl-2,3-dihydrobenzofuran-5-ol.
Studies of Polystyrene-Based Ion-Exchange Fiber. IV. A Novel Fiber-Form Material for Adsorption and Immobilization of Biologically-Active Proteins
Authors: Yoshioka Toshio , Shimamura Masaharu 
Published: July 2006

Abstract
A new polystyrene-based ion-exchange fiber (IONEX) has a large surface area per unit weight and has been studied for its ability to adsorb and immobilize biologically-active proteins. A strong cation IONEX was found to be able to effectively adsorb hemoglobin and albumin, invertase, and glucose isomerase were readily adsorbed to a strong anion IONEX. The adsorption of these proteins to IONEX was found to take place through an electrostatic force. The adsorption capacity for proteins became exceedingly large (ca. 300 mg g−1) with an increase in the water-holding capacity of the fiber. The activities of the invertase and glucose isomerase immobilized to the fiber exhibited 40–50 and 75–80%, respectively, of those of native enzymes. A continuous inversion of sucrose was also carried out using immobilized invertase. From these results, this fibrous ion exchanger with a high water-holding capacity is considered to be an excellent material for the adsorption and immobilization of proteins.