bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Reaction Involving One Electron Transfer in Key Step. NO2-Catalyzed Halogenation of Polycyclic Aromatic Compounds with Metal Halides
Authors: Sugiyama Takashi 
Published: July 2006

Abstract
In the co-existence of catalytic amount of nitrogen dioxide and oxygen, aluminum halide, titanium(IV) halide, and some other metal halides have been found to be highly selective and regiospecific halogenating agents for polycyclic aromatic compounds, including anthracene, pyrene, benz[a]anthracene, chrysene, phenanthrene, naphthalene, triphenylene, fluoranthene, benzo[b]thiophene, and dibenzothiophene.
Enzymatic Synthesis of Pyridine Nucleotides. Structural Property of Some New NAD-analogs, and Base Conditions Available for the Analog Formation
Authors: Tono-oka Shuichi 
Published: July 2006

Abstract
Some new β-NAD-analogs were prepared by a base-exchange reaction catalyzed by pig-brain NADase. The analogs produced from methyl 4-(methylamino)- and 4-(dimethylamino)nicotinates were proved to be 1,4-dihydropyridine form. On the contrary, the analog obtained from 4-(acetylamino)nicotinamide was shown to be a quaternary pyridinium form. Moreover, an unexpected analog of 1,4-dihydro-4-pyridinone form was given by 4-methoxynicotinamide. It was shown to be indispensable for the formation of NAD-analog that the ring nitrogen of pyridine bases concerned should at least be free from protonation around pH 7. Interestingly nicotinic acids with 4-amino, methylamino, and dimethylamino groups were found to be much more basic for the ring nitrogen atom than their respective methyl esters.
Oxidation of Lipids. II. Rate of Inhibition of Oxidation by α-Tocopherol and Hindered Phenols Measured by Chemiluminescence
Authors: Niki Etsuo , Tanimura Ritsuko , Kamiya Yoshio 
Published: July 2006

Abstract
The rate constants for the interactions of peroxyl radicals with α-tocopherol and hindered phenols were determined by chemiluminescence method. The thermal decomposition of di-t-butyl diperoxyoxalate in o-dichlorobenzene with and without ethylbenzene was found to give chemiluminescence under oxygen. 9,10-Dibromoanthracene was an effective activator. The addition of 1-tetralyl hydroperoxide gave chemiluminescence both in the presence and absence of oxygen, while the addition of t-butyl hydroperoxide suppressed the chemiluminescence almost completely even under oxygen. The addition of α-tocopherol and phenols also diminished the chemiluminescence, but after reaching the minimum intensity it again increased as the inhibitors were consumed. The rate constants for the scavenging of 1-phenylethylperoxyl radical by α-tocopherol, 2,4,6-tri-t-butylphenol and 2,6-di-t-butyl-4-methylphenol were obtained as 1.5×105, 1.2×104, and 1.0×104 M−1 s−1 (1 M=1 mol dm−3) respectively.
Attractive Interactions between Carbonyls and Groups Bearing Lone-pair Electrons in Triptycene Systems
Authors: Oki Michinori , Izumi Giichi , Yamamoto Gaku , Nakamura Nobuo 
Published: July 2006

Abstract
Compounds which carry a methoxyl or a chloro group in 1-position and a substituted carbonylmethyl group in 9-position of the triptycene system have been prepared to examine populations of rotamers by 1H NMR spectra. The methoxy compounds favored the ±sc conformations, whereas the ap conformations were relatively favored in the chloro compounds. The results indicate that there are attractive interactions between the carbonyls and a methoxyl or a chloro group and are discussed from the electron-accepting ability of the carbonyl group and the electron-donating ability of the methoxyl and the chloro groups. An aldehyde group was apparently less able to interact with electron-donors than a ketone. This apparent anomaly was discussed from the intramolecular dipolar interactions.
Photochemical Reactions of Aromatic Compounds. XXXVII. Solvent Effects on Fluorescence Quenching and Photoreactions of Naphthonitrile–Olefin and Furan Systems. Qualitative Consideration on Electronic Structures and Reactivities of Nonemissive Exciplexes
Authors: Pac Chyongjin , Yasuda Masahide , Shima Kensuke , Sakurai Hiroshi 
Published: July 2006

Abstract
Solvent effects on the fluorescence-quenching rate constants (γkc) as well as on the quantum yields (φ∞−A) of photoreactions have been investigated for the nonemissive exciplex systems in which 1- or 2-naphthonitrile is the electron acceptor whereas the donors are some enol ethers, a few simple alkenes, furan, 2-methylfuran, and ethyl phenyl ether. On the basis of the assumption of the solvent as a continuous dielectric medium, the relationships between electronic structures and reactivities of nonemissive exciplexes have been qualitatively estimated from the plots of logγkc and log[φ∞−A⁄(1−φ∞−A)] vs. (ε−1)⁄(2ε+1). In nonpolar and moderately polar aprotic solvents, the nonemissive exciplexes have low charge-transfer contributions but relatively high reactivities in the cycloaddition while much larger charge-transfer contributions are induced in more polar alcoholic solvents; the reactivities in the protic solvents decrease with the increase of solvent polarity. For some exciplexes, the occurrence of complete electron transfer in very polar solvents such as ethanol, methanol, and acetonitrile is strongly suggested from the product distributions. The possible availability of ET(30) or Z value as a scale of solvent polarity has been tested for the solvent effects on the processes from the nonemissive exciplexes.
Room-temperature Fluorine Addition to Fluoro-substituted Naphthalene Derivative Using Xenon Difluoride
Authors: Zajc Barbara , Zupan Marko 
Published: July 2006

Abstract
Room-temperature boron trifluoride catalyzed addition of fluorine to octafluoronaphthalene with xenon difluoride proceeds as 1,4- and 1,2-addition, giving decafluoro-1,4-dihydronaphthalene and decafluoro-1,2-dihydronaphthalene. Fluorine addition to 2-methoxy- and 2-ethoxyheptafluoronaphthalene gave only 1,4-adducts, while reaction with 2-isopropoxyheptafluoronaphthalene resulted in octafluoro-1,2-dihydronaphthalene-2-one and 6-isopropoxynonafluoro-1,4-dihydronaphthalene.
Study of Molecular Complexes by Refractometry
Authors: Singh Ram Adhar , Bhat Subray Narayan 
Published: July 2006

Abstract
The refractive index measurement technique is used to investigate molecular complex formation in liquid solutions and the association constants are determined directly. The association constants at 25 °C and heats of complexation for naphthalene–phenol, benzene–tetracyanoethylene, p-xylene–tetracyanoethylene, hexamethylbenzene–tetracyanoethylene, and triethylamine–iodine in cyclohexane are 8.2, 2.2, 8.6, 231, and 4620 dm3 mol−1 and 19.25, 11.30, 18.00, 32.21, and 51.46 kJ/mol, respectively. These values agree well with the literature data obtained by spectroscopic methods.
A Perturbative Study of Medium and Long Range Interactions between Some Characteristic Fragments of Lipid–Protein Systems
Authors: Raudino Antonio , Zuccarello Felice , Buemi Giuseppe , Rigano Carmelo 
Published: July 2006

Abstract
An intermolecular perturbation theory, originally presented by Murrell and developed by use of the LCAO approximation, was applied to a theoretical study on the interaction of a hydrogen-bonded dimer of formamide with ethane molecule or ammonium ion in order to simulate interaction between characteristic frameworks of proteins and lipids. Ethane has a preferential orientation parallel to the carbonyl bond supported by the prevailing charge-transfer contribution. Ammonium ion has preferential interaction regions dependent on the balance between the charge-transfer and coulombic forces along the NH···OC axis.
Adsorption of Electron Acceptors on Titania
Authors: Esumi Kunio , Meguro Kenjiro 
Published: July 2006

Abstract
Four electron acceptors with electron affinities ranging from 1.26 to 2.84 eV were adsorbed from acetonitrile solution on to a titania sample. On adsorption, radical anions were formed on the titania surface as a result of electron transfer to the acceptors from the surface of the titania. The concentration of radical anions thus formed decreased with the decreasing electron affinity of the acceptors; the decrease is steep between 1.26 and 1.77 eV. These results suggest that the limit of electron transfer from the titania surface to the acceptor ranges between 1.77 and 1.26 eV in the electron affinity of the acceptor.
Effect of the Chlorine Contents on the Lattice Constants of β-FeOOH
Authors: Ohyabu Matashige , Ujihira Yusuke 
Published: July 2006

Abstract
The lattice constants of β-FeOOH including chlorine and fluorine, were determined by X-ray diffractometry. The chlorine-content dependence of the lattice constants showed that chlorine ions are distributed at random, occupying certain sites of β-FeOOH.
The Cheletropic Addition of Dichlorocarbene to 2-Phenylsulfonyl-2-azabicyclo[3.2.1]octa-3,6-diene and Its 8-Substituted Derivatives
Authors: Inoue Hiroo , Tokisato Kazuhiko , Umano Katsumi 
Published: July 2006

Abstract
It was found that dichlorocarbene undergoes exo addition preferentially on the C3–C4 double bond of 2-phenylsulfonyl-2-azabicyclo[3.2.1]octa-3,6-diene and endo addition on that of 2-phenylsulfonyl-syn-8-benzoyloxy-2-azabicyclo[3.2.1]octa-3,6-diene.
The Reaction of 1-Methoxycarbonyl-2-imidazolidone with Phenylmagnesium Bromide
Authors: Matsumura Noboru , Matsukawa Kimihiro , Sakaguchi Yujiro , Inoue Hiroo 
Published: July 2006

Abstract
It is found that 1-methoxycarbonyl- or 1-phenoxycarbonyl-2-imidazolidone reacts with phenylmagnesium bromide to afford benzophenone and triphenylmethanol, together with 2-imidazolidone, by nucleophilic attack on the carbonyl group at the side chain.
Electrosynthesis of 2-Methyl-1,4-naphthoquinone (Vitamin K3) Directly from 2-Methyl-5,8-dihydro-1,4-naphthalenediol by a Four-electron Oxidation Procedure
Authors: Torii Sigeru , Tanaka Hideo , Nakane Shoji 
Published: July 2006

Abstract
A straightforward synthesis of Vitamin K3 was performed by electrolysis of 2-methyl-5,8-dihydro-1,4-naphthalenediol in a MeCN–t-BuOH (9/1)–LiClO4–(Pt or C electrodes) system. The use of perchlorate salts or tetrafluoroborate salts as supporting electrolytes in various electrolysis systems, such as AcOH–t-BuOH (9/1)–LiClO4–(Pt) and AcOEt–t-BuOH (9/1)–Bu4NClO4–(Pt), also provided good results, while the use of Et4NOTs in MeOH afforded 2-methyl-5,8-dihydro-1,4-naphthoquinone, preferentially.
Heterocylic Studies. Synthesis of 9-Hydroxybenzimidazo[2,1-b]benzothiazoles and Their Quaternary Derivatives
Authors: Soni R P , Saxena J P 
Published: July 2006

Abstract
A series of substituted 9-hydroxybenzimidazo[2,1-b]benzothiazoles has been synthesized. The position of phenolic hydroxyl group in these compounds has been ascertained on the basis of spectral data.
Static and Dynamic Properties of Quinoxalines in the Phosphorescent Triplet State from Optically Detected Magnetic Resonance
Authors: Suga Kazuhiko , Kinoshita Minoru 
Published: July 2006

Abstract
The static and dynamic properties of the phosphorescent triplet states of quinoxaline and 2,3-disubstituted derivatives in hexane have been studied at 1.4 K using the methods of optically detected magnetic resonance. In addition, the absorption and phosphorescence excitation spectra have also been measured to attain the information about the low lying excited states. A systematic comparison has been made for the purpose of examining the effect of substitution. A significant enhancement of the pumping rates for the y spin sublevel observed in the chlorinesubstituted derivatives is concluded to be due to the additional indirect process of intersystem crossing which occurs from S1 of n,π* to T1 passing through the intermediate triplet state of π,π*. A detailed discussion on the observed phosphorescence spectra originating from the three sublevels has achieved a satisfactory success in understanding the mechanisms responsible for the radiative decay processes. It is concluded that the mechanisms due to vibronic coupling with closely lying n,π* triplet states are of little importance in the systems studies here.
ESR Studies on the Free Radical Intermediates in the Photoreduction of Duroquinone in Alcohol Solutions
Authors: Noda Shoji , Sanehira Kiyoshi , Doba Takahisa , Yoshida Hiroshi 
Published: July 2006

Abstract
ESR measurements during photolysis of duroquinone (DQ) solutions in ethanol and 2-propanol have revealed the generation of both durosemiquinone anion (DQ−) and durosemiquinone radicals (DQH·). Correspondingly, alkoxyl radicals have been detected from the photolyzed solutions by the spin trapping-ESR technique, though the quantum yield of their formation is very low (10−3 for the ethanol solution). Main conclusions deduced from the present work are (1) that DQ\ewdot is generated through the one-electron reduction of DQ by α-hydroxyalkyl radical and through the photodissociation of (DQ-DQH2) complex, and (2) that DQH· is generated through the hydrogen abstraction of 3DQ* either from solvent alcohols or from photoproduct durohydroquinone (DQH2). The one-electron reduction in alcohol solution previously reported for p-benzoquinone is a minor pathway of chemical quenching of 3DQ*. The quantum yield of the DQH2 formation in an early period of photolysis of a dilute DQ in methanol, ethanol, and 2-propanol has been observed to be 0.12, 0.23, and 0.36 respectively. These values are discussed in terms of the mechanism of the quinone photorecduction.
Studies on 2-Aziridinecarboxylic Acid. V. Formation of Dehydroamino Acid Containing Peptides via the Isomerization by NaI of 2-Aziridinecarboxylic Acid Containing Peptides
Authors: Okawa Kenji , Nakajima Kiichiro , Tanaka Takumi , Neya Masahiro 
Published: July 2006

Abstract
The 2-aziridinecarboxylic acid residue in peptides was isomerized with NaI in an acetone solution into the corresponding dehydroalanine or dehydro-2-aminobutyric acid derivatives, but not into the corresponding 2-oxazoline derivatives.
The Nature of Oxygen Species Responsible for Propene Oxidation over V–Mo and V–Sn Oxides
Authors: Ono Takehiko , Kubokawa Yutaka 
Published: July 2006

Abstract
The rate of oxidation of C3H6 has been investigated over V–Mo oxides using 18O2(99%) tracer. The extent of participation of lattice oxygen in the oxidation increases with increasing MoO3 content, showing a maximum at V–Mo (33 mol% of MoO3) oxide. The rate of oxidation of C3H6 varies parallel to the extent of participation of lattice oxygen. A marked dependence of the rate of oxidation upon oxygen pressure observed with V–Mo(33) oxide is attributed to its high reducibility. Similar experiments have been carried out with V–Sn (94 mol% of SnO2) oxide. The rate of reduction of the oxide with C3H6 is about ten times smaller than that of the corresponding catalytic oxidation of C3H6, suggesting the participation of adsorbed oxygen in the oxidation. The results of 18O tracer experiments show participation of lattice oxygen in the oxidation. A mechanism which explains such conflicting results has been proposed.
The Decomposition of Water on the CO- or H2-reduced Indium Oxide
Authors: Otsuka Kiyoshi , Yasui Takao , Morikawa Akira 
Published: July 2006

Abstract
The reduction of In2O3 by H2 or CO and the reoxidation of the reduced oxide by water, accompanying the formation of hydrogen, have been investigated at ≥673 K. The reduction of In2O3 and the decomposition of water have been expressed by the forward reaction and the backward reaction respectively of this equation: In2O3(s)+xH2(g)\ightleftarrowsIn2O3−x(s)+xH2(g), where In2O3−x(s) is a mixture of indium metal and In2O3. Surface oxygen atoms of fresh In2O3 are easily removed by H2- or CO-reduction at 673 K, but they can not be reformed by oxidation with water. This explains the observation that the quantity of hydrogen produced in the oxidation step was somewhat deficient compared to that consumed by the reduction. The maximum rate of the decomposition of water is observed when the oxide has been reduced up to a 50% reduction-level. However, an excessive reduction (greater than 85%) results in a sharp decrease in the rate of the decomposition of water, probably because of the isolation of metallic indium from the host In2O3.
Chemistry of 1,3-Glycol Derivatives. IV. Mechanism of the Solvolyses of 2,4-Pentanediol Derivatives and the Reactions of the Proposed Intermediate Acetoxonium Ions with Carbanions and Hydride
Authors: Itoh Osamu , Iwakoshi Naoki , Saitoh Toshihide , Katano Hiroaki , Fujisawa Yoshiki , Hasegawa Yoshinori , Sugita Toshio , Ichikawa Katsuhiko 
Published: July 2006

Abstract
Regio- and stereochemical studies of the solvolyses of various kinds of 2,4-pentanediol derivatives, including 2-acetoxy-4-tosylates, cyclic orthoformates and orthoacetates, have been done and the previously proposed mechanism has been partially revised. The reactions of the proposed intermediate acetoxonium ions with carbanions and with a hydride ion have also been studied.
The Kinetics of Bromate-Cerium(III) and -Iron(II) Reactions
Authors: Yoshida Toshihisa , Ushiki Yataro 
Published: July 2006

Abstract
The bromate-cerium(III) and -iron(II) reactions in acidic media were examined with special reference to their induction periods and reaction rates. In the bromate-cerium(III) reaction, the induction period is followed by a burst of cerium(IV) formation and then a gradual formation of cerium(IV). In the bromate-iron(II) reaction, a slow decrease occurs only in acidic media, even without bromate, so it may differ from the decrease in the tris(1,10-phenanthroline)iron(II) concentration based on the oxidation by bromate. It was interpreted as the dissociation from [Fe(phen)3]2+ to [Fe(phen)2]2+ and phen. This is the induction period for iron(III) formation, which follows as the burst. The induction period and the rates of cerium(IV) or iron(III) formation can be interpreted on the basis of the mechanism for the Belousov oscillatory and the present redox reactions proposed by Noyes and his co-workers.
Spin Density Distribution and Energy Stabilization in the Cation Radicals of Multilayered Compounds
Authors: Ohya-Nishiguchi Hiroaki , Terahara Atsushi , Hirota Noboru , Sakata Yoshiteru , Misumi Soichi 
Published: July 2006

Abstract
The spin density distributions and the energy stabilizations in the polymer cation radicals (Rn+·) have been investigated by measuring the oxidation potentials (E1⁄2°) and the electron spin resonance (ESR) spectra of the cation radicals generated by the electrochemical oxidations of some multilayered compounds. E1⁄2° decreased monotonically as the number of layers increased. The spin densities on the aromatic rings have been estimated from the hyperfine coupling constants with the help of the McLachlan’s and INDO calculation. It was found that the spin density tends to localize in the central moieties in Rnn+·. The localization of the spin density and the energy stabilization are interpreted with a simple theoretical model of Rnn+·, which takes into accounts the repulsion integral (γ1) and resonance integral (ζ) between the nearest neighbor molecules. The comparison with the experimental data has lead to the numerical estimates of γ1=0.1 eV and ζ=0.4 eV.
Nanosecond Laser Flash Photolysis of 1-Anilinonaphthalene
Authors: Nakamura Hiroki , Tanaka Jiro , Nakashima Nobuaki , Yoshihara Keitaro 
Published: July 2006

Abstract
The photoionization mechanism of 1-anilinonaphthalene (1-AN) was investigated by a nanosecond laser flash photolysis and the result was compared with that of 8-anilino-1-naphthalenesulfonate (ANS). The photoionization of 1-AN in polar solvent is shown to occur through a biphotonic process via a triplet state; the mechanism is different from those of ANS, in which an intermediate of a charge transfer to solvent (CTTS) state was observed. Thus the major deactivation process of the lowest excited singlet state is an intersystem crossing in 1-AN, while it is a transition to the CTTS state in ANS which might be stabilized by the sulfonato group.
Flash Pyrolysis of Selenides. Syntheses of Bibenzyls, Olefins, and Related Compounds
Authors: Higuchi Hiroyuki , Otsubo Tetsuo , Ogura Fumio , Yamaguchi Hachiro , Sakata Yoshiteru , Misumi Soichi 
Published: July 2006

Abstract
Pyrolyses of a series of selenides and diselenides were studied. Selenides and diselenides bound with an active methylene group like benzyl gave a variety of substituted bibenzyls and related ethane derivatives in high yields. Other diselenides were easily caused to cleave to give various aromatic and aliphatic olefins in good yields together with elemental selenium. Lepidopterene, [2.2]paracyclophane, and benzocyclobutene were prepared by thermal cleavage of their corresponding phenylselenomethyl-substituted compounds as an application of the pyrolysis concerned.
Phase Equilibria in the Gd2O3–V2O3–V2O5 System at 1200 °C
Authors: Kitayama Kenzo , Katsura Takashi 
Published: July 2006

Abstract
The phase equilibria in the Gd2O3–V2O3–V2O5 system are studied at 1200 °C by changing the oxygen partial pressure from −0.68(air) to −12.50 in terms of logPO2. In this system, Gd2O3, GdVO4, GdVO3, 0.81Gd2O3. 0.19V2O5, V2O3, V3O5, V4O7, V5O9, V6O11, V7O13, and VO2 are stable. GdVO4 and 0.81Gd2O3·0.19V2O5 have nonstoichiometric compositions. The crystallographic properties of the latter are determined with reference to the indices of a certain compound, 4Tm2O3·V2O5. On the basis of the phase equilibria, the Gibbs free energy of these two reactions: 31/50 Gd2O3+19⁄50 GdVO3+19⁄100 O2= Gd1.62V0.38O3.38 and: GdVO3+1⁄2 O2= GdVO4 are determined to be 57.0 and 127.8 kJ respectively.
Separation and Quantification for Various Phosphorus Oxoacids by Isotachophoresis
Authors: Yagi Takao , Kojima Kayoko , Nariai Hiroyuki , Motooka Itaru 
Published: July 2006

Abstract
The analytical procedure for the separation and quantification of various phosphorus oxoacids was investigated by the capillary type isotachophoresis. The various phosphorus oxoacids, such as linear-, cyclic-, and lower phosphorus oxoacids, were separated at pH 5.5 with a 0.01 mol dm−3 hydrochloric acid–histidine–0.1% triton X-100 mixture as the leading electrolyte and a 0.01 mol dm−3 hexanoic acid as the terminating electrolyte. The PU value increased in the order of P3m&lt;P4m&lt;P3&lt;P2&lt;\overset1P&lt;\overset3P&lt;P1. The calibration curves for the various phosphorus oxoacids were linear in the range of 0.5–3.5 μg as phosphorus oxoacids. Coefficients of variation for the measured phosphorus oxoacids were less than 2% except for P3. Separation times were approximately 15 min. This procedure was applied to the ground phoshates.
Synthesis of [3.3](1,3)Ferrocenophane and Its Derivatives
Authors: Kasahara Akira , Izumi Taeko , Yoshida Yoshio , Shimizu Iwao 
Published: July 2006

Abstract
[3.3](1,3)Ferrocenophane-1,15-diene-3,14-dione was synthesized via the base-catalyzed condensation of 1,3-ferrocenedicarbaldehyde with 1,3-diacetylferrocene utilizing the high dilution technique. The reduction of the compound with LiAlH4–AlCl3 and the subsequent catalytic hydrogenation led to the formation of [3.3](1,3)ferrocenophane. The transannular π-electronic interactions between the two ferrocene moieties in these compounds were examined on the basis of NMR and electronic spectra.
2-Methylamino-4,5-imidazoledione. A Revised Structure for Creatone, Methylparabanic Acid Imide, and (3-Methylguanidino)glyoxylic Acid
Authors: Yamamoto Hiroshi , Pfleiderer Wolfgang 
Published: July 2006

Abstract
The previous structures presented for the Hg(OAc)2 oxidation product of creatine, the condensation product of methylguanidine and diethyl oxalate, and the peracid oxidation product of 1-methyl-2-amino-dihydropyrimidines are all replaced by a revised formulation, 2-methylamino-1H-imidazole-4,5-dione on the basis of the pKa values (0.62 and 7.87) and the spectra. The equilibria between this thermodynamically controlled product and the previous formulations are discussed.