bluuebunny/crossref_metadata_2025_split huggingface dataset:
Anharmonic Potential Functions and Intrinsic Reaction Coordinates of Polyatomic Molecules
Authors: Machida Katsunosuke 
Published: July 2006

Abstract
A general method has been developed to describe the atomic motion along a given intrinsic reaction coordinate (IRC) in the vicinity of the potential minimum of a polyatomic molecule whose anharmonic force constants are known experimentally or theoretically. The components of the position vector of a configuration point on an IRC in the normal coordinate space are expanded as power series of the path length from the origin measured along the IRC. Explicit expressions of the expansion coefficients up to the third order have been given in terms of the normal frequencies and the anharmonic force constants with respect to the normal coordinates. The atomic loci along the IRC are given by transformation from the normal coordinates to the Cartesian displacements. Through application to formaldehyde and water, the method has proved to be useful to check if a given normal coordinate can be connected to any dissociation path on large distortion of the molecule.
Thermal and Dielectric Properties of Liquid Crystals with a Coumarin Skeleton
Authors: Nakai Hidetsugu , Takenaka Shunsuke , Kusabayashi Shigekazu 
Published: July 2006

Abstract
In order to examine the liquid crystalline properties of coumain, 3-X- and 7-Y-substituted coumarins where X=cyano and n-alkoxycarbonyl, and Y=4-n-alkyl- and 4-n-alkoxybenzoyl, 4-alkoxycinnamoyloxy, 4′-alkyl- and 4′-alkoxy-4-biphenylylcarbonyloxy, and 4-(4-alkoxybenzoyloxy)benzoyloxy (4) groups have been prepared. The compounds with X=alkoxycarbonyl group tend to exhibit strong smectic properties, and compounds with X=cyano exhibit stable nematic phases, whereas the coumarin core seems to facilitate a lateral separation of molecules in the mesophase due to its large molecular breadth. The heptyloxy homolog of 4 exhibits a reentrant behavior of the C–Nre–SA–N–I type. The thermal properties are discussed in terms of the polarity and polarizability of coumarin, and the molecular structure. The dielectric properties of the compounds have also been examined and discussed in terms of the polarity of the coumarin core.
The Study of Metal Colloids Produced by Means of Gas Evaporation Technique. I. Preparation Method and Optical Properties in Ethanol
Authors: Kimura Keisaku , Bandow Shunji 
Published: July 2006

Abstract
Three new methods for the preparation of metal colloid in organic solvent are presented. These methods were the matrix isolation method, the gas flow-cold trap method and the gas flow–solution trap method; the latter was found to give a good colloid solution for the optical measurements. The metals reported are high purity Ag, Au, Cu, In, Al, Ca, Sn, and Pb. The stability of the colloid is dependent on the kind of metals: Al, In, Au, and Ag are stable, and Pb, Sn, Ca, and Cu are unstable. The optical absorption spectra of these sols were measured in ethanol solution in Ar atmosphere. They are discussed in relation to those reported on the solid matrix or on the solid substrate.
The Preparation of Tri-t-butoxysiloxy-substituted 1,3,5-Triazines
Authors: Abe Yoshimoto , Nagao Yukinori , Sato Kenji , Misono Takahisa 
Published: July 2006

Abstract
The title derivatives were prepared to obtain 1,3,5-triazines with a better solubility than chloro- and amino-1,3,5-triazine, which are not very soluble in common organic solvents.
Thermodynamic Study for Dibenzo-24-crown-8 Complexes with Alkali Metal Ions in Nonaqueous Solvents
Authors: Takeda Yasuyuki 
Published: July 2006

Abstract
Complex-formation constants (KML+) of dibenzo-24-crown-8 (DB24C8) with alkali metal ions in acetonitrile and the solubility of DB24C8 in methanol, acetonitrile, and propylene carbonate were determined conductometrically and spectrophotometrically at 25 °C, respectively. The KML+ value sequences of the alkali metal ions with DB24C8 are Na+&gt;Cs+&gt;K+=Rb+. Dibenzo-24-crown-8 shows no remarkable selectivity for the alkali metal ions in acetonitrile. Transfer activity coefficients of the DB24C8 complexes with alkali metal ions were calculated from these data and literature values of transfer activity coefficients of alkali metal ions. For the same alkali metal ion, the bulky DB24C8-alkali metal ion complex is more soluble in the aprotic solvents acetonitrile and propylene carbonate than in the protic solvent methanol as compared with the case of the alkali metal ion itself. The transfer activity coefficient of the DB24C8-alkali metal ion complex from methanol to acetonitrile is somewhat sensitive to the variation of the alkali metal ion in the DB24C8 cavity, whereas the mobility of the DB24C8-alkali metal ion complex at the same concentration in the solvents is not sensitive.
Hydrophobic Vitamin B12. I. Preparation and Axial Ligation Behavior of Hydrophobic Vitamin B12r
Authors: Murakami Yukito , Hisaeda Yoshio , Kajihara Akiro 
Published: July 2006

Abstract
Heptamethyl cobyrinate perchlorate, [Cob(II)ester]ClO4, was prepared in a good yield from cyanocobalamin. This hydrophobic complex is structurally comparable to the base-off form of vitamin B12r. Thermodynamic parameters (ΔG, ΔH, and ΔS) for axial ligation of [Cob(II)ester]ClO4 with various amines in dichloromethane and toluene were determined by electronic spectroscopy. The isoequilibrium temperatures obtained from plots of ΔH vs. ΔS were 194±20 and 317±20 K in dichloromethane and toluene, respectively. The equilibrium is primarily controlled by entropy at ordinary temperatures and the logK1 value varies sensitively along with the change in pKa of amine in dichloromethane, while the equilibrium values were almost invariant to the choice of amine in toluene because the measurements were carried out near the isoequilibrium temperature. The logK1 value for [Cob(II)ester]ClO4, different from the case of cobalt(II)-porphyrin complexes, depends on the nature of solvent used and undergoes wide variations. The possible functions of equatorial ligands involved in these two different complexes in the axial ligation behavior were discussed.
13C NMR Signal Assignments of Herqueinone and Its Phenalenone Derivatives
Authors: Suga Takayuki , Yoshioka Takamitsu , Hirata Toshifumi , Aoki Tadashi 
Published: July 2006

Abstract
The full assignments of the 13C NMR signals of the herqueinone-type phenalenone, herqueinone, were established by a combination of the single-frequency off-resonance decoupling technique and the 13C-enrichment technique using the 13C-labeled tracer. Furthermore, the full assignments of the 13C NMR signals of deoxyherqueinone-type, dihydroherqueinone-type, and xanthoherqueinone-type phenalenone were completed on the basis of the application of the chemical shift rule and the mutual comparison of their chemical shifts.
Studies on Heterocyclic Analogs of Azulenes. XI. Syntheses and Cycloadditions of Cyclohepta[4,5]pyrrolo[1,2-a]imidazoles and Cyclohept[d]imidazo[1,2-a]imidazoles
Authors: Abe Noritaka , Nishiwaki Tarozaemon , Yamamoto Hideko , Kunishige Noboru 
Published: July 2006

Abstract
Cyclohepta[4,5]pyrrolo[1,2-a]imidazoles (1,3a-diazacyclopent[a]azulenes) (2) and cyclohept[d]imidazo[1,2-a]imidazoles (1,3a,9-triazacyclopent[a]azulenes) (6) were synthesized from 2-aminocyclohepta[b]pyrroles and 2-aminocycloheptimidazole, respectively, in moderate to good yields. Reactions of 2 and 6 with reactive acetylenes gave 2-azacyclohepta[ef]cycl[3.2.2]azines together with bis(1,3a-diazacyclopent[a]azuleno)[1,7]diaza[12]annulenes (4) and 2,3-diazacyclohepta[ef]cycl[3.2.2]azines together with bis(1,3a,9-triazacyclopent[a]azuleno)[1,7]diaza[12]annulenes (8), respectively. Reactions of 2 and 6 with electron deficient olefins gave 4 and 8, respectively. These reactions proceeded regioselectively via 1,10-dipolar intermediates.
X-Ray Diffraction Study on the Coordination Structure of Chlorocopper(II) Complexes in Highly Concentrated Methanolic CuCl2 Solution
Authors: Ichihashi Mitsuyoshi , Wakita Hisanobu , Masuda Isao 
Published: July 2006

Abstract
The structures of the solute complexes existing in methanolic CuCl2 solutions with concentrations of 1.055–3.250 mol dm−3 were investigated by X-ray diffraction analysis. The solute complexes which were predominantly present could be formulated as [CuCln(CH3OH)6–n] (n=1–3); they have an axially elongated octahedral structure including Cl− at the equatorial site. The Cu-O bond distance was 2.230–2.238 Å. Methanol molecules were coordinated at the equatorial site with the Cu-O bond distance of 1.926–1.950 Å and at the axial site with that of 2.423–2.473 Å. When the initial concentration of CuCl2 was kept within the range examined here, almost all of the Cu2+ ions formed chloro complexes.
Reduction of Sulfonic Acids and Related Organosulfur Compounds with Triphenylphosphine–Iodine System
Authors: Oae Shigeru , Togo Hideo 
Published: July 2006

Abstract
Arenesulfonic acids, their sodium salts, and alkyl arenesulfonates can be reduced readily to the corresponding arenethiols quantitatively by treatment with a mixture of triphenylphosphine and a catalytic amount of iodine, while alkanesulfonic acids, sulfinic acids, disulfides, thiosulfonic testers, and sulfonates are also readily reduced to the corresponding thiols similarly. Upon treatment with a mixture of triphenylphosphine and excess iodine, however, these aliphatic sulfur compounds are converted eventually to the corresponding alkyl iodides. The relative reactivities of these sulfonyl derivatives in the reaction with the triphenylphosphine–iodine system are the following. Aromatic series: ArSO2Cl, ArSO2SAr′&gt;ArSO2H&gt;ArSO3R&gt;ArSO3−HNBu3+ (or PyH+)&gt;ArSO3H&gt;ArSO2SO2Ar&gt;&gt;ArSO2CH2C(CH3)3, ArSO3Ar′. Aliphatic series: RSO2Cl, RSO2SR′, RSO2−HNBu3+&gt;RSO3−HNBu3+&gt;RSSR, RSO2H&gt;RSO3H&gt;RSH&gt;RSO3R′. In these reactions, the arenesulfonic acids bearing electron-donating substituents can be reduced more readily than those having electron-withdrawing substituents.
Biomimetic Reduction of Sulfuric Acid
Authors: Oae Shigeru , Togo Hideo 
Published: July 2006

Abstract
Sulfuric acid and sodium sulfate were readily reduced to elemental sulfur and hydrogen sulfide upon treatment with a mixture of either one of polyphosphoric acid derivatives, PPE, PPA, and P4O10, which can form a mixed anhydride having –P–O–S– linkage, and iodide or thiol. Sulfur dioxide, which is undoubtedly one of important intermediates, was trapped by p-tolyllithium to afford p-toluenesulfinic acid which was converted to p-tolyl methyl sulfone upon treatment with methyl iodide, though the yield was low. Sulfur trioxide which has been postulated as the key intermediate in the biological reduction of inorganic sulfate, was also trapped by mesitylene to give mesitylenesulfonic acid in a high yield. The reduction of sulfate to elemental sulfur and hydrogen sulfide is considered to proceed through the course which resembles the biological reaction path involved in the assimilatory metabolism of inorganic sulfate in microorganisms and plants.
57Fe Spin-lattice Relaxation Time of Fe(CO)5 and Ferrocene
Authors: Nozawa Tsunenori , Hatano Masahiro , Sato Mitsuo , Toida Yoshiharu , Batholdi Enrico 
Published: July 2006

Abstract
Spin-lattice relaxation times (T1’s) of 57Fe were determined by the inversion recovery method to be 80 (±10) s at 293 K and 4 (±1) s at 303 K for Fe(CO)5 and ferrocene, respectively. Predominant relaxation mechanisms were considered to be chemical shift anisotropy and spin-rotation for the former and the latter complexes, respectively.
Study of the Behavior of “Uptake and Release” of Oxygen into Perfluorocarbon–Water Emulsions
Authors: Meguro Kenjiro , Watanabe Hiroshi , Kato Hiromu , Ogihara Kimihiko , Esumi Kunio 
Published: July 2006

Abstract
Stable O/W type emulsions of perfluorocarbon such as perfluorodecalin (FDC) and perfluorotributylamine (FTBA) were prepared by using poly(oxyethylene)-poly(oxypropylene) block copolymer (Pluronic F-68) and sorbitan monolaurate (SL-10) as emulsifiers. The relationships between the behavior of “uptake and release” of oxygen into the emulsions and the factors responsible for a stable emulsion were studied. The initial rates of “uptake and release” of oxygen into the emulsions decreased with increasing the mean particle size, the concentration of emulsifiers, and the viscosities of the emulsions. On the other hand, the saturated amount of oxygen in the emulsions was independent on the mean particle size, but depended on the total amount of the perfluorocarbons in the emulsion.
The Preparation of Poly(dicarbon monofluoride) via the Graphite Intercalation Compound
Authors: Watanabe Nobuatsu , Nakajima Tsuyoshi , Kawaguchi Masayuki , Izumi Akira 
Published: July 2006

Abstract
Poly(dicarbon monofluoride), (C2F)n is prepared with a higher reaction rate via the graphite interca lation compound formed through a reaction with F2 and AlF3 than from exfoliated graphite itself. The former process also has the advantage of including the formation of exfoliated graphite by the decomposition of an intercalation compound and its fluorination. The graphite fluoride thus prepared contained (C2F)n by 60–78%. The reaction time required for completing the reaction did not give a linear relationship, but a minimum point around 267×102 Pa against the fluorine pressure and there was almost no increase above 667×102 Pa of fluorine. However, the F/C ratios of graphite fluoride had, inversely, a maximum point against the fluorine pressure, indicating that the (C2F)n content in graphite fluoride was approximately proportional to the reaction time.
Enthalpies of Combustion of Organic Compounds. IV. Acetanilide and Nicotinic Acid
Authors: Sato-Toshima Tomoko , Kamaguchi Akeji , Nishiyama Keiichi , Sakiyama Minoru , Seki Syûzô 
Published: July 2006

Abstract
Standard energies of combustion at 298.15 K have been determined for crystalline acetanilide and nicotinic acid by static oxygen bomb calorimetry. Derived standard enthalpies of combustion and of formation are −(4224.8±1.0) and −(209.5±1.5) kJ mol−1 for acetanilide, and −(2730.83±0.48) and −(344.81±0.92) kJ mol−1 for nicotinic acid, respectively. Nicotinic acid pellets of 1.2 g in mass showed remarkable tendency to spatter when partially burnt. Factors governing the completeness of combustion of the material have been explored through 28 test combustion experiments.
Electrophilic Additions of Rigid Methylenecyclohexane. A Correlation of the Stereochemical Course of the Methoxymercuration-demercuration and the 1,3-Dipolar Cycloaddition
Authors: Nitta Makoto , Omata Akihiko , Hirayama Setsuko , Yajima Yuji 
Published: July 2006

Abstract
The stereochemical course of the methoxymercuration-demercurations and the 1,3-dipolar cycloadditions of mesitonitrile oxide on the exocyclic double bonds of 2,4-dimethyl-7-methylenetetracyclo[3.3.0.0.2,804,6]octan-3-one (4a), its corresponding exo-3-ol (4b), endo-3-ol (4c), and 2,3,4-trimethyl-7-methylenetetracyclo[3.3.0.0.2,804,6]octan-3-exo-ol (4d) were investigated. In the methoxymercurations of 4a and 4b, the methoxyl group was incorporated in the exo and endo positions, with endo preferred over exo. On the other hand, 4c and 4d underwent the stereospecific incorporation of the methoxyl group in the endo position. In the 1,3-dipolar cycloadditions, 4a or 4b afforded exo- and endo-adducts, with the exo-adduct preferred. These results seem to imply similar stereochemical course of the formation of the mercurinium-ion intermediates and the 1,3-dipolar cycloadditions. The results are discussed on the basis of the steric hindrance of the molecular framework and the substituents which are located at the C-3 position.
Simple Synthesis and Chemicophysical Properties of Polyoxa[n]ferrocenophanes and Its Alkali Metal Complexes
Authors: Akabori Sadatoshi , Habata Yoichi , Sakamoto Yhoko , Sato Masaru , Ebine Seiji 
Published: July 2006

Abstract
Polyoxaferrocenophanes were synthesized by a one-pot reaction of 1,1′-diacetoxyferrocene with dichloride. Crystalline 1 : 1 complexes of 3a with LiSCN, NaSCN, and KSCN were isolated. The 1H-NMR and Mössbauer spectra of these complexes suggest the possibility of a certain interaction between the iron atom of the ferrocene nuclei and complexed cation. The new type of ferrocenophane 3a extracts a thallium ion most effectively, the extractability of several metal ions being in this order; Tl+&gt;Rb+&gt;K+&gt;Cs+&gt;Na+.
Chemical Studies on the Mistletoe. V. The Structure of Taxillusin, a New Flavonoid Glycoside Isolated from Taxillus kaempferi
Authors: Sakurai Atsushi , Okumura Yasuaki 
Published: July 2006

Abstract
A new flavonoid glycoside, taxillusin was isolated from Taxillus kaempferi (DC.) Danser and (2R,3R)-taxifolin 3-β-d-glucopyranoside 6″-gallate was assigned to this substance from studies on the hydrolysis products and from analyses of the 1H-NMR and carbon-13 NMR spectra.
NAD(P)+-NAD(P)H Model. 39. Asymmetric Reduction by 1,4-Dihydronicotinamide Derivative Bound to Protein
Authors: Ohno Atsuyoshi , Ushida Satoshi , Oka Shinzaburo 
Published: July 2006

Abstract
1,4-Dihydronicotinamide derivatives covalently bound to NH2 or SH group of proteins such as reduced keratin (RK), egg white albumin (EWA), and bovine serum albumin (BSA) have been synthesized and subjected to the reductions of α,α,α-trifluoroacetophenone derivatives. Chiral alcohol is obtained in the reaction with 1,4-dihydronicotinamide modified by the SH group of BSA.
Electronic Structures and Spectra of a Novel Diquinone; 1,4 : 5,8-Anthracenediquinone
Authors: Fukuda Masahiko , Tajiri Akio , Oda Masaji , Hatano Masahiro 
Published: July 2006

Abstract
Assignment of the electronic absorption spectrum of 1,4 : 5,8-anthracenediquinone (1,4 : 5,8-ADQ) has been carried out with the aid of magnetic circular dichroism and LCAO MO SCF CI calculations including all valence electrons. The lowest energy absorption region of 1,4 : 5,8-ADQ has been revealed to be composed of the n-π* transition or transitions. The higher energy absorption region has been concluded to consist of four π-π* transitions, which are regarded as Lb, La, Ba, and Bb in the Platt’s notation for anthracene. The above assignment of 1,4 : 5,8-ADQ has been experimentally confirmed with its linear dichroism spectra in stretched polyethylene sheets and its circular dichroism spectra in the β-cyclodextrin solution. The relationship between the absorption spectra of 1,4 : 5,8-ADQ and 1,4-naphthoquinone has been discussed from the experimental and theoretical points of view.
Excited-state Reactions of Coumarins in Aqueous Solutions. I. The Phototautomerization of 7-Hydroxycoumarin and Its Derivative
Authors: Moriya Tetsuo 
Published: July 2006

Abstract
The kinetics and mechanism of the reaction in the photo-excited state of 7-hydroxycoumarin and its derivative have been studied in aqueous solutions by means of measuring the fluorescence spectra and the fluorescence lifetime. The four fluorescence bands have been identified as emissions from the neutral, anionic, tautomeric, and cationic forms of 7-hydroxycoumarins. The quantitative analysis was performed by using the rate equation which included the term for the direct conversion of the excited neutral molecule to its tautomer in addition to the usual reaction term of dissociation. The rate constants of the tautomerization and dissociation were discussed in detail, and it was revealed that the tautomerization in aqueous solutions was mainly caused by the transfer of a proton between two active sites in the molecule. Such an intramolecular proton-transfer of the coumarins, found first in this paper, is considered to be promoted by water molecules with a hydrogen bond surrounding the excited molecule.
Study of the Mixed Solutions of an Anionic and a Nonionic Surfactant by Using the Azo-hydrazone Tautomerism of an Acidic Dye
Authors: Meguro Kenjiro , Tabata Yujin , Fujimoto Naoki , Esumi Kunio 
Published: July 2006

Abstract
The absorbances of the azo-hydrazone tautomer of sodium 4-(p-sulfonatophenylazo)-1-naphthol-2-sulfonate dissolved in an aqueous solution of polyethylene glycol octyl dodecyl ether (8ED) were measured in the presence of various concentrations of sodium dodecyl sulfate (SDS). The existence of a mixed micellar region of SDS and 8ED in the bulk solution was confirmed by this azo-hydrazone tautomer method.
The Spectrophotometric Determination of Phosphate and Arsenate by Selective Extraction with Mixed Solvents
Authors: Shida Junichi , Kakizaki Satoru , Hozumi Yasuomi , Itoh Akiko , Matsuo Tsutomu 
Published: July 2006

Abstract
A spectrophotometric method for the simultaneous determination of phosphate and arsenate by selective solvent extraction was examined. First, molybdophosphate was extracted with 1-butanol–chloroform in the presence of molybdoarsenate, and then the molybdoarsenate in the aqueous phase was extracted with MIBK, followed by reduction directly in the organic phase to Molybdenum Blue.
Optical Determination of Carboxylate Ions Utilizing Flocculation of Colloidal Al(OH)3
Authors: Muto Masayuki , Yamahachi Yuko 
Published: July 2006

Abstract
Flocculation of colloidal Al(OH)3 occurs by adding a suitable amount of Congo Red, and the supernatant liquid become scolorless. When some carboxylate ions are present in this colloidal mixture, the quantity of Al(OH)3 decreases because of the formation of complexes, and then excess Congo Red gives a red color to the supernatant liquid. The indirect determination of some kinds of carboxylate ions was carried out by applying the measurement of optical absorption to the supernatant fraction.
Phase Equilibria in the La2O3–V2O3–V2O5 System at 1200 °C
Authors: Kitayama Kenzo , Zoshima Daizo , Katsura Takashi 
Published: July 2006

Abstract
The phase equilibria in the La2O3–V2O3–V2O5 system were established at 1200 °C by changing oxygen partial pressures from −0.68 (air) to −13.00 in terms of logPO2. In this system, 0.81La2O3·0.19V2O5(La1.62V0.38O3.38), 3La2O3·V2O5(La3VO7), 0.71La2O3·0.29V2O5(La1.42V0.58O3.58), LaVO4, LaVO3, VnO2n−1 (n=2–7), and VO2 were stable. LaVO3, LaVO4, La1.62V0.38O3.38, La3VO7, and La1.42V0.58O3.58 have nonstoichiometric compositions. On the basis of the phase equilibria, the Gibbs energies of the reactions:
31⁄50La2O3+19⁄50LaVO3+19⁄100O2=La1.62V0.38O3.38
50⁄31La1.62V0.38O3.38+12⁄31LaVO3+6⁄31O2=La3VO7
21⁄50La3VO7+4⁄25 LaVO3+2⁄25O2=La1.42V0.58O3.58
LaVO3+1⁄2O2=LaVO4
were determined to be −64.0, −55.8, −21.6, and −131.5 kJ respectively.
Epilaurallene, a New Nonterpenoid C15-Bromoallene from the Red Alga Laurencia nipponica Yamada
Authors: Suzuki Minoru , Koizumi Kuniko , Kikuchi Hajime , Suzuki Teruaki , Kurosawa Etsuro 
Published: July 2006

Abstract
A new halogenated nonterpenoid C15-compound, epilaurallene, has been isolated as a major constituent from the title alga along with several known compounds, and its structure was determined by the spectral and chemical methods. Epilaurallene is an epimer at C-4 of laurallene and was shown to possess S-configuration at C-4.
Oxidative Dehydrogenation of Bis(salicylideneaminato)copper(II) Complex in Pyridine and Formation of 2-Cyanophenolato Complex
Authors: Matsushita Takayuki , Shono Toshiyuki 
Published: July 2006

Abstract
The copper(II) complex of salicylideneamine (salamH) reacts with molecular oxygen in pyridine to give the 2-cyanophenolato complex, [Cu(2-CNphO)2(py)2], in good yield, where 2-CNphOH and py denote 2-cyanophenol and pyridine, respectively. This complex was characterized by the infrared and electronic spectra and by its magnetic susceptibilities, and was compared with the authentic complex, [Cu(2-CNphO)2(py)2]. The mechanism for the oxidation of the coordinated imino groups is discussed.