bluuebunny/crossref_metadata_2025_split huggingface dataset:
Preparation of Red Organic Pigment with Phenylated Silica Gel as Core
Authors: Suzuki Mituru , Itô Seisirô , Kuwahara Tosihide 
Published: July 2006

Abstract
The silanols on the surface of silica gel were chlorinated and a phenyl group was introduced onto the silica gel (Remark: Graphics omitted.) by phenylating with phenyllithium. The surface group was derived to a structure similar to Sudan I by nitration, reduction, diazotization, and coupling (with 2-naphthol). The prepared pigment showed approximately the same color as Sudan I, and had very good resistance to water.
The Formation of Vinyl Sulfides by the Cleavage of the Carbon-Sulfur Bond in Dithioacetals with CuCl2
Authors: Oida Tatsuo , Tanimoto Shigeo , Ikehira Hideyuki , Okano Masaya 
Published: July 2006

Abstract
The elimination of arene- and alkanethiol from diaryl and dialkyl dithioacetals, in the presence of copper(I) or copper(II) salt plus tertiary amine, to produce the corresponding aryl and alkyl vinyl sulfides, respectively, has been studied. The employment of a combination of 2 mol equiv. of CuCl2 and 2 mol equiv. of N,N-diisopropylethylamine is most favorable.
Magnetic and Spectral Properties of 3,5-Dichloropyridine Adducts of Dimeric Copper(II) Acetate, Chloroacetate, and Dichloroacetate
Authors: Muto Yoneichiro , Tokii Tadashi , Chijiwa Kiyohiko , Kato Michinobu 
Published: July 2006

Abstract
Three complexes with the empirical formula of Cu(RCOO)2·L, where R=CH3, CH2Cl, or CHCl2 and L=3,5-dichloropyridine, were prepared and studied. These complexes display the antiferromagnetic behavior typical of dimeric copper(II) carboxylates. The singlet-triplet splitting energy (−2J) is 349 cm−1 for the acetate, 340 cm−1 for the monochloroacetate and 312 cm−1 for the dichloroacetate. Comparison of their magnetic and electronic spectral properties with those of the corresponding pyridine adducts indicates that both the −2J and \ ildeνmax(absorption maximum of Band I) values of the respective 3,5-dichloropyridine adducts are higher than those of the pyridine adducts. The influence of the pyridines on both the magnetic and spectral properties was discussed.
Kinetics and Equilibrium Studies on the Anation Reactions in Pentakis(dimethyl sulfoxide)dioxouranium(VI) and Tetrakis(hexamethylphosphoric triamide)dioxouranium(VI) Ions in Nonaqueous Media
Authors: Doine Hideo , Ikeda Yasuhisa , Tomiyasu Hiroshi , Fukutomi Hiroshi 
Published: July 2006

Abstract
The anation reactions in [UO2(dmso)5]2+ (dmso=dimethyl sulfoxide) and [UO2(hmpa)4]2+ (hmpa=hexamethylphosphoric triamide) ions by SCN− and N3−have been studied by the stopped-flow method in DMSO and acetonitrile. For the anation reactions of [UO2(dmso)5]2+ in DMSO as a medium, the pseudo-first order rate constant(kobsd) is expressed by kobsd={k−1+(k1+k−1)×Kos[X]}/(1+Kos[X]), where X=SCN− and [UO2(dmso)5]2+ for the anation reactions by SCN− and N3−, respectively. The values of k1, k−1, and Kos at 25 °C are 2.06×102 s−1, 62 s−1, 35 M−1 (M=mol dm−3), and 7.60×102 s−1, 0.0 s−1, and 41 M−1 for the SCN− and N3− anation reactions in [UO2(dmso)5]2+, respectively. For the anation reaction in [UO2(hmpa)4]2+ by SCN−, the pseudo-first order rate constant was found to be proportional to the concentrations of [UO2(hmpa)4]2+ and free HMPA: kobsd=kf[UO2(hmpa)42+]+kb[HMPA]free. The values of kf and kb at 25 °C are 9.70×103 M−1 s−1 and 9.05×102 M−1 s−1, respectively. The equilibrium constants for the titled reactions were also measured at 25 °C: K=85 M−1for the anation reaction of [UO2(dmso)5]2+ by SCN− in DMSO and K’=42.7 for the SCN− anation reaction in [UO2(hmpa)4]2+ in acetonitrile. The kinetic results suggest that the anation reactions in uranyl complexes proceed through an associative or an associative interchange mechanism.
Pyridoxal Methochloride Catalysis of the β-Elimination Reaction of Methyl 3-Chloroalaninate in Water
Authors: Kondo Hiroki , Morita Kanzi , Kitamikado Tatsuya , Sunamoto Junzo 
Published: July 2006

Abstract
The β-elimination reaction of methyl 3-chloroalaninate has been investigated in the absence and presence of pyridoxal methochloride (2) or pyridoxal (3). Apparently, compound 2 was about twice as effective as 3 in the catalytic reaction that proceeds via a Schiff base of substrate and 2 or 3. The pH-rate profiles for the catalytic reaction with 2 and 3 were analyzed in terms of ionization of the various Schiff base species present in solution. It was found that the reactivity of the Schiff base decreases as the ionization of the molecule progresses. The reaction mechanism and its relevance to the catalysis of pyridoxal phosphate–dependent enzymes are discussed.
Kinetics of the Racemization and Dissociation of Tris(1,10-phenanthroline)iron(II). The Aggregate Formation of the Complex Cation with 1-Alkanesulfonate Anions through Hydrophobic Interaction
Authors: Tachiyashiki Satoshi , Yamatera Hideo 
Published: July 2006

Abstract
The kinetics of the racemization and dissociation of [Fe(phen)3]2+ were investigated in the presence of a series of 1-alkanesulfonate ions (n-CnH2n+1SO3−, n=2,4,6,…,14). The racemization rate increased, while the dissociation rate decreased, gradually as a function of the alkanesulfonate concentration at low concentrations of each alkanesulfonate. With alkanesulfonates of n≥8, the second phase of rate changes, i.e., steep increases in both rates, were observed at higher concentrations. The gradual initial changes in the rates were explained in terms of the formation of the 1:1 aggregate of the complex cation with the alkanesulfonate ion caused by hydrophobic interaction. The formation constant (mol−1 dm3) increased almost exponentially from 4 (n=4) to 770 (n=14) with the increase in the alkyl-chain length, the energy of the hydrophobic interaction of the complex cation and the alkanesulfonate anion being 0.9 kJ mol−1 per methylene group of the latter. The second phase of the rate changes were explained in terms of the formation of the 1:m aggregate of the complex cation with the alkanesulfonate ions. The rate behavior of the hydrophobic aggregates is discussed in connection with the reaction mechanisms of the racemization and dissociation of [Fe(phen)3]2+.
Solvent Effects on the Intensity of the nπ* Absorption Spectra of 1-Phenylethylenetrithiocarbonate and p-Benzoquinones
Authors: Jinnouchi Yasufumi , Kohno Motohisa , Kuboyama Akira 
Published: July 2006

Abstract
The nπ* absorption intensities of 1-phenylethylene trithiocarbonate (1), p-benzoquinone (2), and 2,5-di-t-butyl-p-benzoquinone (3) in nonpolar solvents are compared with the theoretical ones calculated by the use of Abe’s formula, in which the Onsager-cavity field is used. For 3, the theoretical intensities are well correlated with the observed ones, whereas for the others there are discrepancies, especially for 1. These discrepancies are attributed to strong dispersion-force interactions with the solvents.
Application of Liquid Crystals for Gas-Liquid Chromatography
Authors: Sakagami Sakumitsu , Nakamizo Minoru 
Published: July 2006

Abstract
A liquid crystalline homologous series of N-[4-(4-alkoxybenzoyloxy)benzylidene]-4-cyanoanilines was applied as a stationary liquid phase for the gas-liquid chromatographic separation of various positional isomers. It is shown that the nematic phase has higher selectivity for several positional isomers compared with the other mesomorphic phases.
Studies of Bitter Peptides from Casein Hydrolyzate. VIII. Bitter Taste of Cyclic Analog of BPIa (Arg–Gly–Pro–Pro–Phe–Ile–Val)
Authors: Miyake Ichizo , Kouge Katsushige , Kanehisa Hidenori , Okai Hideo 
Published: July 2006

Abstract
In order to elucidate the structure-taste relationship of bitter peptide BPIa (Arg–Gly–Pro–Pro–Phe–Ile–Val), cyclo-BPIa was synthesized. The result of both taste and CD examinations suggested that the bitterness of BPIa is caused by its spatial structure, which is analogous to that of cyclo-BPIa.
The Complexation of Zinc Tetraphenylporphyrintrisulfonate by Viologen and Its Role in Photoredox Processes
Authors: Okura Ichiro , Kusunoki Shin , Aono Shigetoshi 
Published: July 2006

Abstract
The formation of the cation radicals of viologen dyes was established when an aqueous solution containing zinc tetraphenylporphyrintrisulfonate (Zn–TPPS3), viologen dye, and 2-mercaptoethanol was irradiated by visible light. The reduction of viologen has been studied kinetically; its reduction rate may be expressed as follows:
v=\fracd[V+]dt=\left(\frack3[Zn−TPPS3]01+K1[V2+]+K2[V+]\ight)\left(\frack4[V2+]k−3+k4[V2+]\ight)\left(\frack6[RSH]k5[V+]+k6[RSH]\ight),
where [V2+], [V+], and [RSH] are the concentrations of the oxidized form and the reduced form of viologen, and 2-mercaptoethanol respectively. On the basis of the rate expression, a reaction mechanism containing the complexation of Zn–TPPS3 by viologen was proposed. On the addition of hydrogenase to the above photoirradiation system, hydrogen evolution was observed by the irradiation of visible light.
Kinetics and Equilibrium Studies of the Formation of a Cobalt(II) Complex with N-(8-Quinolyl)aminoacetic Acid
Authors: Hara Yasuo , Okamoto Ken-ichi , Hidaka Jinsai , Einaga Hisahiko 
Published: July 2006

Abstract
Stopped-flow kinetic and equilibrium studies have been made of the formation of a cobalt(II) complex with N-(8-quinolyl)aminoacetic acid in 0.10 mol dm−3 aqueous sodium chloride containing 12 vol% ethanol at 25 °C. Octahedral mono- and bis-ligand complexes were formed via the two pathways of the reactions of deprotonated and monoprotonated ligand species with the aquacobalt(II) ion. The coordination mechanism is discussed.
Kinetic Studies of the Hydrolysis of Diketene Catalyzed by the Chloropalladium(II) Complex
Authors: Okeya Seichi , Kawaguchi Shinichi 
Published: July 2006

Abstract
When diketene and sodium tetrachloropalladate(II) are mixed in aqueous solution, color of the solution changes promptly from dark red to yellow. During this fast primary reaction about one equivalent of diketene is consumed and acetoacetic acid (H2A) is retained as a trihapto ligand in [PdCl2(HA)]− (2). The succeeding steady hydrolysis of diketene (S) proceeds as a pseudo first-order reaction, obeying the rate law: –d[S]/dt=kobsd[S]=(k0+kcat)[S], kcat=kobsd–k0=(k1+k2/[H+])[PdII]/[Cl−], where k1=2.0×10−5 s−1 and k2=2.96×10−6 mol dm−3 s−1 at 0 °C and μ=1.0 mol dm−3 (HClO4 and NaClO4). A mechanism which postulates complex 2 as the effective catalyst is proposed to explain the observed two-term rate equation.
Equilibrium Solubilities of Iodine Vapor in Water
Authors: Sanemasa Isao , Kobayashi Toyohisa , Piao Cheng Yun , Deguchi Toshio 
Published: July 2006

Abstract
Equilibrium solubilities of iodine vapor in water were measured by introducing iodine vapor, in equilibrium with solid iodine, into water and by circulating it in a closed system, and Henry’s law constants were determined. Equilibrium distributions of iodine vapor between a gas phase and an aqueous phase were also measured by another method, and partition coefficients were determined. The solubilities of iodine vapor in water estimated from both the Henry’s law constants and the partition coefficients are compared with those of solid iodine reported in the literature. Thermodynamic parameters for the hydration of iodine vapor are evaluated experimentally.
Aggregate Morphology and Hydrogenation Reactivity of Functionalized Bilayer Membrane Composed of Peptide Lipid Having NADH Activity
Authors: Murakami Yukito , Kikuchi Jun-ichi , Nishida Koji , Nakano Akio 
Published: July 2006

Abstract
A peptide lipid bearing the 1,4-dihydronicotinamide moiety, N,N-dihexadecyl-Nα-[1-(6-trimethylammoniohexyl)-1,4-dihydro-3-pyridylcarbonyl]-l-alaninamide bromide [N+C6(NAH)Ala2C16], and its dehydrogenated form, N,N-dihexadecyl-Nα-[1-(6-trimethylammoniohexyl)pyridinium-3-ylcarbonyl]-l-alaninamide chloride bromide [N+C6(NA+)Ala2C16], were prepared. Both lipids formed bilayer membranes when they were dispersed in aqueous media, and the 1,4-dihydronicotinamide and nicotinamide moieties of the respective lipid molecules were placed in the so-called hydrogen-belt domain upon membrane formation. In an aqueous dispersion of the latter dicationic lipid, relatively small multilayered vesicles were predominantly formed while the related monocationic lipids bearing the same double alkyl chain composed much larger vesicles and/or lamellae. Formation of the charge-transfer (CT) complex of the nicotinamide moiety of N+C6(NA+)Ala2C16 with 3-indolylacetic acid was much enhanced in the membrane through tight electrostatic interaction. The bilayer membrane composed of N+C6(NAH)Ala2C16 acted as a potential reductant toward anionic substrates in aqueous media. The high reactivity is gained primarily by the effective incorporation of the substrates into the hydrogen-belt domain through electrostatic, hydrogen bonding, and CT interactions and partly by the proximity effect which becomes valid between the 1,4-dihydronicotinamide moiety and the bound substrate molecule.
Chemical Synthesis of Fully Active and Heat-stable Fragments of Heat-stable Enterotoxin of Enterotoxigenic Escherichia coli Strain 18D
Authors: Yoshimura Shoko , Takao Toshifumi , Ikemura Haruo , Aimoto Saburo , Shimonishi Yasutsugu , Hara Saburo , Takeda Tae , Takeda Yoshifumi , Miwatani Toshio 
Published: July 2006

Abstract
Two shorter peptides of a heat-stable enterotoxin (STp), which is produced by enterotoxigenic Escherichia coli strain 18D, were prepared by two different procedures; i) chemical synthesis and ii) Edman-degradation of STp. These peptides (designated as STp(4–18) and STp(5–18)) corresponded to 15 and 14 amino acid residues in the sequence of STp without three and four residues, respectively, of the N-terminus. Peptides STp(4–18) and STp(5–18) prepared by chemical synthesis had the same biological and physicochemical properties as the peptides obtained by the Edman method. Furthermore, they showed almost the same toxicity as native and synthetic STp, and their toxicity was neutralized by anti-native STp antisera. Synthetic STp(4–18) had similar heat-stability to STp, but synthetic STp(5–18) was much more heat-stable. These findings suggest that the sequence from the Cys residue near the N-terminus to the C-terminal residue is extremely important for the unique characters of toxicity and heat-stability of the toxin.
Vibrational Energy Levels and Infrared Absorption Intensities of Carbon Monoxide
Authors: Miyazaki Tomoo , Matsuura Azuma , Takeuchi Hisao 
Published: July 2006

Abstract
The vibrational energy levels and infrared absorption intensities of carbon monoxide have been calculated with due consideration for the mechanical and electrical anharmonicities of vibration by the use of ab initio molecular orbital calculation in which the C-I treatment and polarization functions were introduced.
The Number of Water Molecules Bound to Insulin
Authors: Nagashima Nobuya , Suzuki Ei-ichiro , Tsuboi Masamichi 
Published: July 2006

Abstract
On cooling an aqueous solution of zinc pig-insulin to −40 °C, 108 water molecules per insulin molecule have been found (by NMR) unfrozen. This number is nearly equal to what was found crystallographically of the water molecules located within 4.7 Å of the protein molecule.
The Formation of Metastable Potassium Trivanadate from Melts
Authors: Kera Yoshiya 
Published: July 2006

Abstract
Potassium vanadates, which were prepared from melts by rapid quenching and slow cooling over the composition range of K2O-contents of C=(K)/(V)=0–0.50, were examined by means of IR spectrometry and X-ray powder diffraction. In the composition range of C≤0.17, mixtures of V2O5, K2V18O45, and K2V8O21 were produced by the slow cooling. At the composition of C=0.33, however, an unknown compound and K2V8O21 were the main products upon rapid quenching from melts, while at C=0.50 the main products were K3V5O14 and an additional unknown compound. The unknown compound was confirmed to be metastable and was formed as a single compound only by a rapid quenching from melts of K2O and V2O5 especially at C=0.37. The X-ray diffractions for the compound were characterized as d=8.2 (very strong), 4.05, and 3.27 Å, and the V=O stretching frequencies, as 995, 968, and 955 cm−1. By comparing these characteristic data with those of lithium trivanadate and sodium trivanadate (γ-phase), it was suggested that the unknown compound was isomorphous with trivanadate (M1+xV3O8).
Characterization of Cobalt(III) Complex with 2-Aminoethaneseleninate. Spontaneous Resolution and Crystal Structure of (−)500CD-(2-Aminoethaneseleninato)bis(ethylenediamine)cobalt(III) Nitrate
Authors: Okamoto Ken-ichi , Konno Takumi , Nomoto Masayo , Einaga Hisahiko , Hidaka Jinsai 
Published: July 2006

Abstract
The crystal structure and the absolute configuration of the spontaneously resolved title complex cation, (−)500CD-[Co(aesei)(en)2]2+, has been determined by X-ray diffraction. The red crystalline needle was monoclinic, space group P21, a=9.572(4), b=10.410(3), c=8.838(5) Å, β=115.35(3)°, Z=2, and the final R value was 0.035 for 2358 independent reflections with |F0|&gt;3σ(|F0|). The crystal used showed a negative CD value at 500 nm and had Δ configuration. The 2-aminoethaneseleninate is bound to the cobalt atom by the nitrogen and oxygen atoms, and the asymmetric selenium atom takes an S configuration. The value of the protonation constant (pKa) was determined to be 1.91±0.05, on the basis of the major absorption spectral change at 304 nm of the title complex by spectrophotometric titration (μ=1.0 mol dm−3 (NaClO4) and 25 °C). The electronic absorption and CD spectral behavior were compared with those of the related sulfinato complexes, in which the S-bonded sulfinato complex, (+)500CD-[Co(S(O)2CH2CH2NH2)(en)2]2+, was resolved in this work.
Bromination of 2,6-Dimethyl-4-methoxybenzyl Alcohol Derivatives
Authors: Nakatani Munehiro , Takahashi Kimi , Watanabe Sumie , Shintoku Atsuko , Hase Tsunao 
Published: July 2006

Abstract
The reaction of 2,6-dimethyl-4-methoxybenzyl alcohols, ethyl ethers, and acetates, possessing electrondonating and -withdrawing groups at the benzylic position, with bromine water was studied at different temperatures. The reaction was strongly affected by the electronegativity of a benzyl substituent to afford bromination products of aromatic nuclei and 2,4-dibromo-3,5-dimethylmethoxybenzene along with 2,4,6-tribromo derivatives formed by the cleavage of C–C bond.
Studies of the Hydrous Tin(IV) Oxide Ion-exchanger. II. Some Properties as a Cation-exchanger
Authors: Inoue Yasushi , Yamazaki Hiromichi 
Published: July 2006

Abstract
In order to elucidate the fundamental properties of hydrous tin(IV) oxide as a cation-exchanger, the stoichiometry of cation exchange and its acid-base property were studied by means of the uptake curves for alkali-metal ions. The results are summarized as follows: 1) The equivalent exchange between the hydrogen ion and either alkali-metal or alkaline-earth-metal ions holds, irrespective of the ionic strength of the solution and the extent of exchange. 2) The water content in the exchanger depends on the ionic composition. 3) This material is an amphoteric ion-exchanger, with at least two kinds of weakly dissociable ion-exchange sites, and the conditional dissociation constant depends on the ionic composition of the exchanger. The stability to various reagents was also examined.
The Effects of Salts on the Solubilities of Benzene, Toluene, Ethylbenzene, and Propylbenzene in Water
Authors: Sanemasa Isao , Arakawa Seiji , Araki Masatake , Deguchi Toshio 
Published: July 2006

Abstract
Salt effects on the solubilities of benzene, toluene, ethylbenzene, and propylbenzene were studied by making use of the solute vapor. The salting coefficients were determined at 25 °C, and the results were compared with the literature values and with those estimated by means of theoretical equations. The McDevit-Long equation did not give satisfactory predictions until the equation was multiplied by a factor of 0.4. The scaled particle theory gave a favorable agreement with the observations in most cases if suitable pair-potential parameters of solutes were used in the calculations.
Physicochemical Speciation of Trace Elements in River Water by Size Fractionation
Authors: Tanizaki Yoshiyuki , Yamazaki Masao , Nagatsuka Sumiko 
Published: July 2006

Abstract
Eight kinds of Millipore filters with different pore sizes (8–0.025 μm) were used for the filtration of two water samples taken from the Tama River. The filtrates were analyzed for 31 elements using a neutron activation analysis. Most alkali and alkaline earth elements were distributed in the smallest size fraction (&lt;0.025 μm). The same fractionation pattern was also recognized for As, Se, Mo, Sb, and W, which tend to form oxoanions. But the major transition elements were concentrated in the larger size fractions (&gt;0.45 μm). For the river water sample with higher concentration of total organic carbon, however, most of such elements were found in the smallest size fraction. The solubilities of rare earth elements bacame higher with increasing their ionic potentials.
A Basic Study of the Amino Acid Residue in Protein. The Role of Hydrocarbon Groups in Enantiomer-differentiating Acylation
Authors: Hiraki Yuji , Tai Akira 
Published: July 2006

Abstract
The enantiomer-differentiating acylation (kinetic resolution) of 1-phenylalkylamines and their derivatives was carried out with (S)-2-phenylbutyric anhydride and its derivatives in aqueous and nonaqueous media. On the basis of the distributions of the two diastereomeric products, the molecular interactions between hydrocarbon residues responsible for the structural recognition of the reacting molecules were studied. In nonpolar media, the (R,S)-isomer was predominantly formed over the (S,S)-isomer. Moreover, the differentiation was mainly controlled by the size of the alkyl substituents of the substrates. In aqueous media, though, the (S,S)-isomer was predominantly formed. By a comparative study of the cyclohexyl analogs of the substrates and the reagents, it was shown that alkyl-phenyl and/or phenyl-phenyl interactions were important in the recognition process. A partitioning process of the substrate into the reagent phase was not effective in the differentiation of the enantiomer by the reaction in suspensions of optically active reagents in highly aqueous media.
Kinetics of the Ligand Exchange Reaction between Tetrakis(acetylacetonato)thorium(IV) and Free Acetylacetone in CD3CN and CDCl3
Authors: Fujiwara Naoshi , Tomiyasu Hiroshi , Fukutomi Hiroshi 
Published: July 2006

Abstract
Kinetics of the ligand exchange reaction between tetrakis(acetylacetonato)thorium(IV) and free acetylacetone in CD3CN and CDCl3 was studied by 1H NMR. The rate law was written as rate =k[Th(acac)4][Hacac]enol, where k=(1.0±0.1)×102 s−1 mol−1 kg at 0 °C in CD3CN and (1.7±0.1)×102 s−1 mol−1 kg at −16 °C in CDCl3. The rates were retarded by addition of bases and the retardation effect well correlated with the donor number of the bases. Under the conditions studied, the activation entropies gave large negative values. A ligand exchange mechanism passing through a nine-coordinate intermediate is proposed to interpret the kinetic law.
Electrophilic Substitution Reactions on Methine Carbon of the Unsymmetrical Tetradentate Schiff Base and its Complexes with Nickel(II) and Copper(II)
Authors: Kasuga Kuninobu , Nagahara Takeo , Masuda Teruaki , Kiyota Shunji , Yamamoto Yasuo 
Published: July 2006

Abstract
A number of unsymmetrical tetradentate Schiff base complexes of nickel(II) and copper(II) having only one methine carbon in the ligand were synthesized and characterized by means of UV and 1H NMR spectra. The kinetic studies of the electrophilic substitution reactions on the methine carbon with N-halogenosuccinimide gave no support to an aromatic character of the chelate ring, being consistent with the results of 1H NMR studies for the nickel(II) complexes.