bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mechanism of Hydrogen Exchange Reactions on 1:2 Electron Donor-Acceptor Complexes of Anthracene with Sodium
Authors: Ichikawa Masaru , Tanaka Sadao , Naito Shuichi , Nakamura Takahiro , Soma Mitsuyuki , Onishi Takaharu , Tamaru Kenzi 
Published: July 2006

Abstract
The mechanisms of the H2–D2 and D2–HZ exchange reactions over 1 : 2 Electron Donor-Acceptor (EDA) complexes of anthracene with sodium, where HZ denotes the EDA complexes, were studied kinetically and spectroscopically in the temperature range 20–90°C. It was found that molecular hydrogen exchanges directly with the hydrogen of the complexes (An2−2Na+ or An−Na+) and also with the monohydroanion complex (AnH−Na+), which is formed by the dissociative adsorption of hydrogen. The H2–D2 exchange reaction proceeded via not only the σ-bonded hydrogen of the complexes, but also homolytically dissociated “mobile” hydrogen.
Ion-Solvent Interaction of Tetraalkylammonium Ions in Solvents of High Dielectric Constant. II. Conductance and Walden Product of Tetraalkylammonium Ions in N-Methylformamide and N-Methylpropionamide at Different Temperatures
Authors: Singh Raj Deo , Gopal Ram 
Published: July 2006

Abstract
Ion-solvent interaction of the tetraalkylammonium ions (R4N+) in N-methylformamide and N-methylpropionamide has been investigated from the electrical conductance point of view. It appears that the R4N+ ions act as net structure breakers in these solvents as in N-methylacetamide. The appreciable negative deviation of the experimental slope of the Λ vs. \sqrtc curves from the theoretical slope suggests some kind of obstruction to the movement of the R4N+ ions, probably due to their unwieldy size or to some kind of cation-anion association, although the usual kind of association is ruled out in view of the high dielectric constant of these solvents. The cation-anion interaction may be the penetration of the cations by the anions which has been suggested as a possible reason for the negative slope in the apparent molal volume vs. \sqrtc curves, obtained at higher concentrations, to which apparent molal volume measurements usually have to be confined on account of difficulties in accurate density measurements at low concentrations. The smaller alkali metal ions appear to be more solvated than the R4N+ ions, so much so that the λ0+-values of Na+ and K+ ions are lower than the corresponding values of the Me4N+ and Et4N+ ions.
Study of Hydration and Association of Ions in Solution. II. Complete Resolution of Tris(ethylenediamine)Cobalt(III), Chromium(III), and Rhodium(III) Complexes by Means of Paper Electrophoresis
Authors: Yoneda Hayami , Miura Takao 
Published: July 2006

Abstract
Complete resolution of racemic [M en3]3+ (M=CoIII, CrIII, and RhIII) by means of electrophoresis was achieved in a background solution of sodium d-tartrate and aluminum chloride. Electrophoretic data obtained under various conditions (various compositions, concentrations, and pH values of supporting electrolyte solutions) indicated that the separation of the enantiomers of [M en3]3+ complexes was accomplished not by the d-tartrate anion but by some aluminum d-tartrate complex anion.
Metal Complexes Containing Six-Membered Chelate Rings. II. Preparation and Structure of 2,4-Pentanediamine Complexes of Cobalt(III)
Authors: Mizukami Fujio , Ito Haruko , Fujita Junnosuke , Saito Kazuo 
Published: July 2006

Abstract
New cobalt(III) complexes containing optically active (RR and SS) and meso(RS) 2,4-pentanediamine (2,4-ptn) have been synthesized. [Co(RR-2,4-ptn)3]3+ gives two diastereoisomers, prismatic crystals with (−)546 rotation and needle-like crystals with (+)546 rotation. The former is produced much more than the latter. The conformations of the RR- (or SS-) and RS-2,4-pentanediamine chelate of the complexes were assigned to λ- (or δ-) twist and chair form, respectively, from comparison of their PMR spectra with those of the corresponding tetra-acetato complexes. [Co(RS-2,4-ptn)3]3+ seems to have fac structure with respect to the coordination of the amino groups adjacent to the R- and S-carbon atoms. The circular dichroism spectra of mono and trans-bis-(RR-2,4-ptn) complexes in the first band region are essentially the same as those of the corresponding R-propylenediamine complexes. The circular dichroism spectra of (+)546- and (−)546-[Co(RR-2,4-ptn)3]3+ and (−)546-[Co(RS-2,4-ptn)3]3+ are very different from those of the triscobalt(III) complexes of R-propylenediamine and trimethylenediamine. Such differences have been discussed with reference to the stereochemistry of six-membered chelate complexes.
ESR Studies of the Copper(II) Complexes of Ammo Acids
Authors: Yokoi Hiroshi , Sai Mitsuru , Isobe Taro , Ohsawa Shigeru 
Published: July 2006

Abstract
The X-band and K-band ESR spectra of the trans-planar copper(II) complexes of amino acids, whose crystal structures are now known, were measured in a polycrystalline state at room temperature and in frozen aqueous-methanolic solutions at the temperature of liquid nitrogen. The polycrystalline samples showed a variety of ESR line shapes, most of which had three different principal g values; g1=2.04–2.07, g2=2.08–2.12, and g3=2.16–2.29. On the other hand, all the ESR line shapes observed for the frozen solutions were quite similar, and they indicate a normal tetragonal copper (II)-ion environment. There was, moreover, a remarkable difference in the g values between the complexes in the two states. The correlation among the g values, the d-d band energies, the bonding parameters (a measure of the degree of covalency of the copper-ligand bondings), and the geometrical configurations of the coordinating atoms for the complexes in a crystal is discussed in some detail.
The Photo-induced Electron Transfer Reactions between Crystals of Aromatic Hydrocarbons and Quinones
Authors: Soma Mitsuyuki 
Published: July 2006

Abstract
The photo-induced electron transfer reactions between crystals of aromatic hydrocarbons and several quinones were studied by measuring the increase of the photocurrent in the crystals due to the carrier injection from the ethanol electrode containing the quinones. The reaction rates were shown to be independent of sorts of quinones used when its concentration was sufficiently high. The excitation limited mechanism of the reaction was proposed to be consistent with this behavior and the observed concentration dependence of the reaction.
Isotopic Exchange Kinetics between Trisacetylacetonatocobalt(III) and Acetylacetone-14C in Organic Solvents
Authors: Saito Kazuo , Murakami Mizue 
Published: July 2006

Abstract
The isotopic exchange proceeds faster than the decomposition of the complex at more than 80°C and below 120°C. McKay plot gives a linear diagram at the initial stage of isotopic exchange. The rate is expressed by R=[complex](k1+k2[acacH]), where acacH stands for free acetylacetone. The Arrhenius activation energy decreases in the order anisole (25 kcal per mole), chlorobenzene (21), and toluene (18) and is subject to acid catalysis with a strong acid as trichloroacetic. Comparison of the data with those of racemization of this complex, and isomerization and inversion of tris(benzoylacetonato)cobalt(III) suggested that k1 represents dissociation mechanism through a five coordinate intermediate containing a unidentate acetylacetonate anion, and the k2 an association mechanism involving association of free acacH with the intermediate.
Peptides Containing Aminophosphonic Acids. I. Reactivity of α-Aminobenzylphosphonic Acid
Authors: Yamauchi Kiyoshi , Kinoshita Masayoshi , Imoto Minoru 
Published: July 2006

Abstract
The chemical reactivity of α-aminobenzylphosphonic acid was investigated in order to survey the methods for incorporating aminophosphonic acids into a peptide chain. The investigation revealed that i) a dipeptide analog linked with a phosphonamide bond could be produced by the reaction of C-protected amino acid with the N-protected aminophosphonomonochloridate, and that ii) amino groups of the aminophosphonic acid possessed a reactivity similar to those of amino acids, and were capable of coupling with N-protected amino acids by means of dicyclohexylcarbodiimide.
A Kinetic Study of the Polymerization of Acrylic Acid in the Presence of Polyvinylpyrrolidone
Authors: Muramatsu Ryo , Shimidzu Takeo 
Published: July 2006

Abstract
The polymerization of acrylic acid (AA) in a dilute aqueous solution in the presence of polyvinylpyrrolidone (PVP) has been studied kinetically, with the extent of polymerization followed by a bromometric titration method. The rate of the polymerization changed characteristically with the amount of PVP in the solution and went through a maximum at a certain initial mole ratio of PVP and AA, [PVP]0/[AA]0, under a constant [AA]0 value. The mole ratio which gave the maximum rate was almost proportional to the reciprocal of [AA]0. In the course of the polymerization, a polymer complex consisting of PVP and polymerized AA was precipitated. Its composition, (PAA)c/(PVP)c, has been found to be different as the polymerization conditions are varied. Hardly no comparable data between the bromometric method and a turbidimetric method used to measure the rate were obtained. The influence of PVP on the polymerization was assumed to be caused by the local concentration of AA in the vicinity of PVP. A mechanism based on the effect of the local concentration, the “polymer atmosphere binding mechanism,” has been found to explain the experimental results well.
Polar Substituent Constants for Substituted Phenyl Groups. The Extended Taft Equation.
Authors: Nagai Yoichiro , Matsumoto Hideyuki , Nakano Taichi , Watanabe Hamao 
Published: July 2006

Abstract
Values of the σ* constants have been defined for some m- and p-substituted phenyl groups from the 29Si–H coupling constants for a series of m- and p-substituted phenylsilanes, phenylmethylsilanes, and phenyldimethylsilanes. The σ* constants for the groups, XC6H4, were found to be directly related to the Hammett σ constants for the ring substituents, X. From this correlation the σ* constants for a number of other substituted phenyl groups have also been calculated. Examples have been presented in which a simple relationship holds between the Taft polar substituent constants including the newly derived σ* constants and molecular properties for a series of compounds covering both aliphatic and aromatic substances. Correlations of reactivities with the extended σ* values have been illustrated and the implications of the results are discussed.
Inositol Derivatives. IV. Synthesis of Anhydro Derivatives of 1,2-O-Cyclohexylidene-inositol
Authors: Suami Tetsuo , Ogawa Seiichiro , Oki Shuichi , Ohashi Kumiko 
Published: July 2006

Abstract
A reaction of 1,2-O-cyclohexylidene-myo-inositol tosylates with sodium methoxide in an appropriate solvent gave nine anhydro derivatives (mono- 6 and di-epoxide 3). The structures of new compounds were determined by proton magnetic resonance (PMR) spectroscopy and the reaction sequences.
Total Syntheses of Carbohydrates, II. Dl-Erythrose and Dl-Threose
Authors: Sonogashira Kenkichi , Nakagawa Masazumi 
Published: July 2006

Abstract
Propargyl alcohol was converted into 4-acetoxy-cis-crotonaldehyde diethyl acetal (III) via three steps, cis-Hydroxylation of III with potassium permanganate followed by acetylation yielded tri-O-acetyl-Dl-erythrose diethyl acetal (IV). Hydrolysis of IV afforded syrupy Dl-erythrose (VI) which could be converted into erythritol (VII) and its dibenzylidene derivative. An acid hydrolysis of III gave 4-acetoxy-crotonaldehyde (VIII) which was converted into triacetyl-Dl-threose diethyl acetal (XI) or Dl-threose pentaacetate (XII). Hydrolysis of XI and XII gave syrupy Dl-threose which could be identified as di-benzylidenethreitol.
Kinetic Studies of Intermolecular Hydrogen Bonding in Carboxylic Acids by Means of Ultrasonic Absorption Measurement. II. Halogeno Carboxylic Acids
Authors: Sano Takayuki , Tatsumoto Nobuhide , Mende Yukio , Yasunaga Tatsuya 
Published: July 2006

Abstract
The ultrasonic absorptions in several halogeno carboxylic acids, such as monochloroacetic, dichloroacetic, trichloroacetic, trifluoroacetic, α-chloropropionic, and β-chloropropionic acids, have been measured in the frequency range from 2.5 to 95 MHz. Excess absorptions were observed in all the acids. The kinetic and the thermodynamic parameters based on the equilibrium between the open dimer and the cyclic dimer were calculated. An application of Taft’s equation, logK=ρ*σ*+sEs, to the results suggests that neither the equilibrium constant nor the rate constant depends on the polarity effect of the alkyl group, but depends mainly on the steric effect, and that the reaction is controlled not only by the enthalpy change, but also by the entropy change.
Syntheses of Benzo[5,6]cyclohept[1,2-b]indol-6-ones
Authors: Yamane Kameji , Fujimori Kunihide 
Published: July 2006

Abstract
The monoarylhydrazones(IIa—c) of benzocycloheptene-5,6-dione (I) underwent Fischer indolization to form 11,12-dihydrobenzo[5,6]cyclohept[1,2-b]indol-6-ones (IIIa—c). The treatment of IIIa—c with N-bromosuc-cinimide gave the benzoindolotropone derivatives (Va—c). Va, Vc, and VI afforded a dibromo compound (VII) on treatment with bromine in acetic acid.
The Powder ESR Spectra of Some Bis(amino acidato)copper(II) Complexes
Authors: Misumi Seizo , Isobe Toshiyuki , Kimoto Shinkichi 
Published: July 2006

Abstract
Copper(II) complexes with some natural amino acids were prepared, and their powder ESR spectra were measured. The pattern types of the ESR spectra of these Cu(II) complexes with amino acids were classified into four types, and by the pattern type, the cis- or trans-isomer was estimated.
Thermal Decomposition of Ammonium Salts of Transition Metal Oxyacids. I. Thermogravimetric Analysis of Ammonium Paramolybdate
Authors: Park Il-Hyun 
Published: July 2006

Abstract
The decomposition of ammonium paramolybdate (APM) has been investigated by using a quartz spring balance in various ambient pressures. APM is decomposed in four or five stages, including a dehydration procedure, depending on the ambient pressures. However, these results do not agree with those of previous reports. This discrepancy may be attributed to the use of a sensitive quartz spring balance, a small amount of a sample, the application of a slow heating rate, or the utilization of DTG curves in the present study. The control of the ambient pressure was effective in investigating the thermogravimetric change in detail, especially in confirming the dehydration reaction. It is also concluded clearly that, in the course of the decomposition process, there is a final decomposition stage which has never been reported. The kinetics of the thermal decomposition was studied. The activation energies of the decomposition of APM under 760 Torr are 38.6, 194.8, 81.9, and 151.2 kcal·mol−1 respectively for the first to the fourth stages.
Reaction of Vinylic Radicals with Oxygen
Authors: Wada Naoto , Tokumaru Katsumi 
Published: July 2006

Abstract
Thermal decomposition of trans-α-phenylcinnamoyl peroxide and t-butyl trans- and cis-α-phenylperoxycinnamates and photolyses of 1,1 -diphenyl-2-iodoethylene and 1,1,2-triphenyl-2-iodoethylene were carried out in benzene under oxygen and their products were determined. The intermediate vinylic radicals, on reaction with oxygen, undergo oxidative cleavage and dioxygenation of their unsaturated bonds. As an example, 1,2-diphenylvinyl radicals give benzaldehyde together with benzoin.
Benzo- and Naphtho-derivatives of Triptycene: Synthesis and Properties
Authors: Sugihashi Makoto , Kawagita Ryosuke , Otsubo Tetsuo , Sakata Yoshiteru , Misumi Soichi 
Published: July 2006

Abstract
Several benzo- and/or naphtho-derivatives of triptycene were prepared in a manner of addition reaction of dehydronaphthalene (XIII) or a new type of aryne, dehydroanthraquinone (XVI) generated from 3-aminoanthraquinone-2-carboxylic acid (XV), with a few acenes. The absorption bands in longer wavelength region of their UV spectra and the chemical shift of bridgehead protons in their NMR spectra led to a conclusion that the spectra of those annelated triptycenes are elucidated in terms of a superposition and a sum of magnetic effects of separated component chromophores, respectively, and thereby indicate a negligible existence of the across-space π-electron interactions, if any, among three aromatic nuclei.
Improved Solid-Phase Synthesis of Tryptophan-Containing Peptides. I. Use of Hydrogen Chloride in Formic Acid as a Reagent for the Cleavage of t-Butyloxycarbonyl Group
Authors: Ohno Motonori , Tsukamoto Sadaji , Makisumi Satoru , Izumiya Nobuo 
Published: July 2006

Abstract
An improved method has been described for the solid-phase synthesis of tryptophan-containing peptides. Hydrogen chloride in formic acid has been introduced as a reagent for the cleavage of the t-butyloxycarbonyl group owing to the stableness of tryptophan and Ni-formyltryptophan in this system. The effectiveness of the new reagent has been demonstrated in the synthesis of the tryptophan-containing heptapeptide, lysylalanylglycyl-leucylglycyltryptophylleucine.
Study on Reverse Osmosis. The Permeation Behavior of Amino Acid Solutions through Cellulose Acetate Membranes
Authors: Kamizawa Chiyoshi , Masuda Hitoshi , Ishizaka Seiichi 
Published: July 2006

Abstract
Transport phenomena of some aliphatic amino acids and aminobenzoic acids were investigated with Loeb type membranes annealed at 60–80°C.
The quantitative relation between permeability through the membrane and dissociation of amino acid was examined. The charged species are rich in the solutions of amino acids such as l-leucine, l-alanine, and l-glutamic acid, regardless of the pH of solution, thus making the rejection by membranes large; the rejection of l-leucine which had a rejection of 35% for NaCl, was 63.2% even for the membrane cured at 60°C. On the other hand, for aminobenzoic acids, the number of uncharged species in solution varied with the change in pH, and the rejection varied with pH. The fluxes of aminobenzoic acids were in linear relation to the calculated amount of uncharged species. The results of adsorption experiments indicate that the amounts of adsorbed aminobenzoic acid to cellulose acetate were in logarithmic relation to calculated amounts of undissociated species. The results support the view that dissociated species are more difficult to be distributed in membrane than undissociated ones.
Kinetics and Stoichiometry of Nitrogen Fixation with TiCl3-Mg and VCL3-Mg in Tetrahydrofuran
Authors: Yamamoto Akio , Go Shigeo , Ookawa Masaharu , Takahashi Mitsuaki , Ikeda Sakuji , Keii Tominaga 
Published: July 2006

Abstract
The kinetics and stoichiometry of nitrogen fixation with TiCl3-Mg and VCl3-Mg in tetrahydrofuran (THF) systems were studied. The systems react with molecular nitrogen at room temperature and normal pressure giving magnesium dichloride and nitrogen-containing complexes of compositions [MNMg2Cl2(THF)], where M=Ti and V, according to the stoichiometry: MCl3(THF)3+\frac52Mg+\frac12N2→[MNMg2Cl2(THF)]+\frac12MgCl2(THF)2. Properties of the isolated nitrogen-containing complexes were examined. Reactions under argon and hydrogen gave hydride-containing complexes. The initial rate of nitrogen fixation was first order with respect to the amounts of MCL3, Mg, and nitrogen pressure. A mechanism involving the complexation of N2 with dimeric M(II) species followed by rate-determining process to react with magnesium is proposed and discussed.
Solvent Shifts of Methyl Proton Resonances of Pinanols and Related Compounds
Authors: Hirata Toshifumi 
Published: July 2006

Abstract
The chemical shifts of methyl protons of a number of bicyclo[3.1.1]heptanols and their acetates were measured on carbon tetrachloride and benzene in order to examine the correlation between the benzene-induced shifts and the spatial arrangements of the functional groups concerned. Thus, the shifts induced by benzene were found to be useful in establishing both the location and the stereochemistry of methyl protons situated in the vicinity of the hydroxyl or the acetoxyl function in a pinane skeleton.
The Reaction of Troponoid with Ylide. III. The Reaction of Tropone with Pyridinium Compounds
Authors: Sugimura Yukio , Soma Nobuo , Kishida Yukichi 
Published: July 2006

Abstract
Phenacylpyridinium ylide (2) reacted with tropone (1) to afford 2-hydroxy-2-phenyl-3-phenacyl-2H-cyclohepta[b]furan (3) which was converted into 2-(1′,2′-dibenzoylethyl)tropone (4). The reactions of tropone with several kinds of pyridinium bromides (7) yielded 2-substituted tropones in the presence of amine, and 1-azaazulene derivatives (9, 10, 11) in a one-step formation in the presence of ammonium acetate.
The Michael Reactions of Substituted 9,9′-Bifluorenylidenes with 2-Iodo-and 2,7-Diiodofluorene, and Some Other Reactions of Iodofluorenes
Authors: Minabe Masahiro , Suzuki Kazuo 
Published: July 2006

Abstract
The Michael-addition reaction between 2-iodofluorene and 9,9′-bifluorenylidene gave exclusively the normal addition product. The same reaction of fluorene with 2,2′-diiodo-9,9′-bifluorenylidene, of 2,7-diiodofluorene with 9,9′-bifluorenylidene, and of fluorene with 2,7,2′,7′-tetraiodo-9,9′-bifluorenylidene afforded not only the normal adducts, but also some abnormal compounds. Some new iodo-substituted fluorenes, -9,9′-bifluorenylidenes, -9,9-bifluorenyls, and -1,4-bis(2,2′-biphenylylene)-1,3-butadienes, were synthesized. The hydrogenolyses of 2- or 2,7-di-iodofluorene with lithium aluminum hydride, Raney nickel, and hydriodic acid were performed relatively smoothly to give fluorene. The Grignard and the Ullmann reactions of 2- or 2,7-diiodofluorene gave the usual, expected compounds, accompanied by some unusual products. The cyano-substituted fluorenes were prepared by the reaction of 2- or 2,7-diiodofluorene with potassium cyanide–cupric cyanide in N,N-dimethylformamide.
Adsorption of Polyethyleneglycol at the Mercury/Solution Interface
Authors: Yoshida Tadashi , Ohsaka Tetsuya , Suzuki Masayuki 
Published: July 2006

Abstract
The adsorption of polyethyleneglycol (PEG) was investigated at the mercury/solution interface by the observation of the differential capacity and the inhibitive action on the deposition of cadmium or copper. From the differential capacity measurements, the adsorption of PEG was found to be controlled by the diffusion of the adsorbate to the dropping mercury electrode under the present experimental conditions. The relation between the time required to attain the saturated adsorption and the bulk concentration (a) was explained approximately by the Koryta equation, though its deviation from the Koryta equation was somewhat larger than that for polyvinylpyrrolidone. When the maximum surface concentration and the mean molecular weight of PEG were expressed by Γm and \barM respectively, the plot of logΓm-log\barM revealed two linear parts crossing each other at \barM=ca. 600. The slope for \barM≥600 was ca. −1, which implied the relation of “\barM·Γm=const.”, i.e., the segment numbers of PEG molecules adsorbed per unit area were constant, independently of \barM, in the region of \barM≥600. The configuration of PEG of \barM&lt;600 at the interface was considered to be different from that of PEG of \barM≥600 because the slope for \barM&lt;600 was different from that for \barM≥600. From the polarographic current measurements i.e., the inhibitive effect on the reduction of Cd2+ or Cu2+), the time (tmi) needed to achieve the maximum inhibition was obtained; it was then compared with that obtained from the capacity data. The relation of “loga=(−1⁄2)logtmi+const.” based on the Koryta equation was approximately applicable to the cases with a relatively large \barM value.