bluuebunny/crossref_metadata_2025 huggingface dataset:
A Computer Program Package for the Analysis, Creation, and Estimation of Generalized Reactions—GRACE. I. Generation of Elementary Reaction Network in Radical Reactions—GRACE(I)
Authors: Yoneda Yukio
Published: July 2006

The system GRACE generates elementary reaction networks for simple reactions including free radicals, ions and even active sites in heterogeneous catalysis, and also predicts the overall reaction rates and the product distributions in radical reactions in the gas phase where the Arrhenius parameters of elementary reactions are available. In this paper, A/GRACE (part A of GRACE) is explained, which prepares elementary reaction networks for radical reactions. The reactant and the product are represented by square symmetric matrices. The off-diagonal elements represent bond multiplicity, or the number of localized electrons, between corresponding atoms, whereas the diagonal elements imply the number of unshared electrons on radical atoms. A reacting system, an ensemble of the participating molecules, is composed of atom groups, each of which consists of a center atom (usually non-hydrogen) and attached hydrogen atom(s), if any. Firstly, all the possible changes in the atom groups are selected, and the permitted combinations are preapred bearing in mind the equivalent groups in the system and the restrictions optioned. The major restriction is the complexity, i.e., the number of ruptured or formed bonds. A direct sum of matrices are prepared from one of the combinations, and the elementary reaction is completed by setting the appropriate numerals, 1 or −1, to the outside elements. Secondly, the procedures are repeated until all the feasible networks are prepared. As an illustration the hydrogenation of ethylene over a heterogeneous catalyst has been cited.
Dechlorination of Polychlorinated Biphenyls by UV-irradiation. V. Reaction of 2,4,6-Trichlorobiphenyl in Neutral and Alkaline Alcoholic Solution
Authors: Nishiwaki Tohru , Usui Masao , Anda Kinji , Hida Mitsuhiko
Published: July 2006

2,4,6-Trichlorobiphenyl and seven other chlorobiphenyls have been photolyzed in both alkaline and neutral 2-propanol in order to investigate the reactivity and selectivity towards dechlorination. Predominant dechlorination at the 2-position has been confirmed for all PCBs in neutral solution and interpreted in terms of the steric and electronic effects of the phenyl group. In the presence of alkali, however, competitive elimination between the ortho and para chlorine atoms of 2,4-dichlorobiphenyl and 2,4,6-trichlorobiphenyl occurred. The photo-dechlorination of 2,3- and 2,5-dichlorobiphenyls took place however only at the ortho position. The dechlorination ratios (ortho/para) were 7.5 and 0.8 for 2,4-dichlorobiphenyl and 2,4,6-trichlorobiphenyl, respectively. This characteristic of the ortho chlorine atom has been elucidated assuming the steric and electronic effects of the phenyl group in the radical anion. A correlation has been found between the reduction potential and the reactivity of PCB in alkaline solution. The differences in reactivity among the chlorobiphenyls has been attributed to the electron acceptabilities in the ground states.
Electronic Properties and π-π* Absorption Spectra of 1- and 2-Methyl-4-amino-5H-[1]benzopyrano[3,4-c]pyridin-5-one
Authors: Inuzuka Kozo , Fujimoto Akira
Published: July 2006

The tautomerization of 4-amino-5H-[1]benzopyrano[3,4-c]pyridin-5-one (BPP) in the ground state has been briefly discussed by the CNDO/2 method. The π-π* absorption spectra of 1-methyl-4-amino-5H-[1]benzopyrano[3,4-c]pyridin-5-one (1-MBPP) and 2-methyl-4-amino-5H-[1]benzopyrano[3,4-c]pyridin-5-one (2-MBPP) in solution have been obtained. Based on the MO calculations of BPP, assignment of the observed π-π* absorption bands of 1-MBPP and 2-MBPP have been made.
The H/D Isotope Effect in the Reaction of Hydrogen Atoms with Olefins
Authors: Ishikawa Yo-ichi , Sato Shin
Published: July 2006

The absolute rate constants of reaction of deuterium atoms with seven simple olefins at room temperature have been measured by using the pulse-radiolysis technique. The comparison with the rate constants of reaction of hydrogen atoms previously obtained shows that the ratios of k(D+olefin)/k(H+olefin) are in the range of 0.7–0.8. This isotope effect is theoretically discussed.
The Synthesis of (±)-Glutinosone
Authors: Murai Akio , Taketsuru Hirofumi , Masamune Tadashi
Published: July 2006

The synthesis of (±)-glutinosone, an antifungal norsesquiterpene from Nicotiana glutinosa infected with tobacco mosaic virus, is described. It has been completed by two processes, one being based on the Robinson annelation method and another on a modification of the Dastur procedure.
Chemistry of Dienyl Anions. III. Crystalline Bis(2,4-pentadienyl)metal Compounds of Be and Zn. Terminally σ-Bonded Structure and Fluxional 1,5-Rearrangement
Authors: Yasuda Hajime , Ohnuma Yasuo , Nakamura Akira , Kai Yasushi , Yasuoka Noritake , Kasai Nobutami
Published: July 2006

A series of bis(dienyl)beryllium and bis(dienyl)zinc compounds were prepared by metal exchange reaction from seven different dienyl anions and were isolated as crystals of TMEDA complexes. Bis(dienyl)beryllium compounds of open chain structure obtained from pentadienyl, 2-methylpentadienyl, and 3-methylpentadienyl anions assume the terminally σ-bonded (E)-2,4-pentadienyl structure in solution as evidenced by 1H-NMR and 13C-NMR spectroscopies. Hydrolysis of these compounds gave 1,4-dienes regioselectively. The corresponding bis(dienyl)zinc compounds exist as a (Z), (E) mixture of teminally σ-bonded structures. An X-ray analysis of pentadienylzinc chloride·TMEDA complex showed that it had terminally σ-bonded (E)-2,4-pentadienyl structure with s-trans conformation. Steric effect of two methyl substituents in bis(2,4-dimethylpentadienyl)zinc induces the (Z) configuration which leads to the fluxional behavior by rapid 1,5-rearrangement above −80 °C.
The Syntheses, Electrical Resistivities, and Electronic Absorption Spectra of Cation–TCNQ–Crown Ether Complexes
Authors: Morinaga Minoru , Nogami Takashi , Kanda Yasuhiro , Matsumoto Tsuruyoshi , Matsuoka Katsumi , Mikawa Hiroshi
Published: July 2006

Crown ether complexes with alkali-metal–, ammonium–, and barium–TCNQ salts were isolated. Their electrical resistivities and electronic absorption spectra were measured. The simple salts, (crown ether)m(M+TCNQ−)n, were almost all insulators with resistivities greater than 107Ω cm. However, the complex salts, (Crown ether)m(M+TCNQ−)n(TCNQ), were much more conductive than simple salts with resistivities of 102–104Ω cm. Three types of electronic-absorption spectra were observed for the simple salts. The simple salts with charge-transfer absorption bands were much more conductive than those without charge-transfer absorption bands.
Circular Dichroism Spectra and Their Relation to Asymmetric Distortion of Some Dimeric Molybdenum(V) Complexes Containing Optically Active Amino Carboxylate
Authors: Suzuki Kimiko Z , Sasaki Yoichi , Ooi Shun’ichiro , Saito Kazuo
Published: July 2006

Circular dichroism (CD) spectra of fifteen kinds of μ-X-μ-Y-bis(oxomolybdenum(V)) complexes, where X=Y=O, X=O and Y=S, and X=Y=S, containing optically active ligands such as (S)-cysteinate, its alkyl esters, (R)-penicillaminate (R-pen), (S)-histidinate, and (R)-propylenediaminetetraacetate, give two distinctive peaks with opposite signs at ca. 26000 and 33000 cm−1 in various media including KBr disks. Close examination of the known X-ray structural data of eight complexes indicated that the pseudo-octahedral coordination sphere of two molybdenum(V) ions are asymmetrically twisted around the Mo–Mo axis. The direction of such a twist for the complexes containing the ester ligands and R-pen, is opposite to that for the complexes with other ligands. The former and latter complexes give positive and negative, and negative and positive CD peaks at ca. 26000 and 33000 cm−1, respectively. Thus the CD signs of the two peaks are related to the asymmetric distortion around the Mo–Mo axis.
Performances of Lead and Copper(II) Ion-selective Electrodes in Metal Buffer Solutions and the Determination of the Stability Constants of Lead and Copper(II) Complexes
Authors: Nakagawa Genkichi , Wada Hiroko , Sako Takeshi
Published: July 2006

The behaviour of lead and copper(II) ion-selective electrodes (Denki Kagaku Keiki Co., Japan) at very low activity levels was examined in metal buffer solutions. In the absence of complexing agents, the Nernstian responses were obtained down to 10−6 mol dm−3 (μ=0.1) Pb2+ in the pH range from 4 to 7, and down to 10−7 mol dm−3 (μ=0.1) Cu2+ in the pH range from 4 to 6. The complexing agents which form stable complexes with Pb or Cu(II) were very effective in lowering the detection limits. The stability constants of the Pb and Cu(II) complexes with several ligands[CH3COO−, 1,10-phenanthroline(Phen), glycine(Hgly), iminodiacetic acid(H2ida), nitrilotriacetic acid(H3nta), etc.] were determined by measuring the activities of the free Pb or Cu(II) ion in metal buffer solutions. However, in spite of the high stability of the Pb– or Cu(II)–edta complex, the lower limit of the electrode response was abnormally high and the stability constant of Pb– or Cu(II)–edta complex could not be obtained. Some reasons for the abnormalities with EDTA were discussed.
Pyrolytic Sulfurization Gas Chromatography. VII. The Simultaneous Determination of the Atomic Ratio between C, H, O, and N in a Halo-organic Compound
Authors: Hara Tadashi , Fujinaga Kaoru , Okui Fujio
Published: July 2006

The halide produced from a halo-organic compound interferes with the simultaneous determination of the atomic ratio between C, H, O, and N in the compound by the pyrolytic sulfurization gas chromatography, but the interference can be eliminated by allowing the pyrolytic sulfurization of the compound to proceed in the presence of the sodium sulfide formed by the reaction between sodium azide and sulfur.
Mössbauer Spectroscopic Studies of the Chemical Effects Associated with 57Co(Electron Capture)57Fe Decay in Tris-β-diketonatocobalt(III) Compounds
Authors: Sakai Yoichi , Endo Kazutoyo , Sano Hirotoshi
Published: July 2006

Magnetic hyperfine structures (hfs) were found in the absorption Mössbauer spectra at 78 K of a paramagnetic iron(III) complex diluted in a diamagnetic cobalt(III) or aluminium(III) complex, such as 57Fe(acac)3 in Co(acac)3, 57Fe(oxin)3 in Al(oxin)3, and 57Fe(dbm)3 in Co(dbm)3 (acac=acetylacetonato, oxin=8-quinolinolato, and dbm=dibenzoylmethanato), showing that the magnetic hfs is caused by the spin-spin relaxation through the surrounding diamagnetic species. In the emission Mössbauer experiments, magnetic hfs was observed at 78 K in 57Co-labelled Co(dbm)3, Co(oxin)3, and polystyrene-diluted Co(acac)3, while it was not observed in 57Co-labelled Co(acac)3 and Co(dpm)3 (dpm=dipivaloylmethanato). The former possess π-conjugated systems to a greater extent than the latter, either in the ligands or in the vicinity of the 57Co-labelled Co(III) species. These results were explained in terms of the radiolytic stabilities of the matrices as well as those of 57Co-labelled compounds by showing that the paramagnetic radicals produced in a diamagnetic matrix quench the magnetic hfs because of the increased spin-spin interaction, as a consequence of the local radiolysis by EC-decay.
The Palladium Catalyzed Nucleophilic Substitution of Aryl Halides by Thiolate Anions
Authors: Migita Toshihiko , Shimizu Tomiya , Asami Yoriyoshi , Shiobara Jun-ichi , Kato Yasuki , Kosugi Masanori
Published: July 2006

In the presence of a catalytic amount of tetrakis(triphenylphosphine) palladium, phenyl and methyl or methoxyphenyl iodides and bromides were found to react with thiolate anions in alcoholic solvents, to give the corresponding aryl sulfides in excellent yield. The reaction is useful to prepare symmetrical or unsymmetrical diaryl sulfides and aryl alkyl sulfides. The reaction mechanism does not involve aryl halide radical anions, but is thought to involve oxidative addition of aryl halide to Pd(0), nucleophilic substitution on the adduct followed by reductive elimination.
The Effects of Added Electrolytes on Mn2+-ion Mobility in Micellar Solutions Studied by the ESR Method
Authors: Ueki Masako , Uzu Yuhei
Published: July 2006

The effects of added electrolytes on manganese-ion mobility in manganese dodecyl sulfate solutions (Mn(DS)2) were measured by means of the ESR method. The addition of aluminum chloride results in line-narrowing and an increase in the signal intensity in the ESR spectra at the concentrations above CMC of the Mn(DS)2 solutions, while the addition of sodium chloride does not affect the ESR spectra.
Chemical Ionization Mass Spectrometry of Epoxides
Authors: Suzuki Shin , Hori Yoshio , Das Rebati C , Koga Osamu
Published: July 2006

The chemical ionization mass spectrometry of epoxides using methane as a reagent gas produces quasi-molecular ions, (M+1)+. This ion has maximum abundance for most epoxides except 1,2-epoxybutane. The method is useful for determination of the molecular weight of epoxides.
Reactions of 3-Acetyltropolone and Its Methyl Ethers with Methylhydrazine
Authors: Yamane Akio , Imafuku Kimiaki , Matsumura Hisashi
Published: July 2006

The reactions of 3-acetyltropolone and 3-acetyl-2-methoxytropone with methylhydrazine gave 1,3-dimethyl-1,8-dihydrocycloheptapyrazol-8-one (3) and 2,3-dimethyl-2,8-dihydrocycloheptapyrazol-8-one. 7-Acetyl-2-methoxytropone reacted with methylhydrazine to afford 1,3-dimethyl-1,8-dihydrocycloheptapyrazol-8-one methylhydrazone, besides a small amount of 3.
An ESR Study of the Interaction of Copper(II) Octaethylporphyrin with π Acceptors
Authors: Yokoi Hiroshi , Iwaizumi Masamoto
Published: July 2006

The π-π interaction of octaethylporphyrincopper(II) (Cu(OEP)) with π acceptors has been investigated in solution and in magnetically-diluted crystals by ESR, and the perpendicular components of the ESR parameters for Cu(OEP) in various states have also been determined with considerable accuracy. It has been revealed that, upon the formation of charge-transfer complexes between Cu(OEP) and π acceptors, the g values decrease slightly, the copper hyperfine coupling constants remain almost unchanged, and the absolute values of the nitrogen superhyperfine coupling constants increase slightly. Accompanying changes in the electronic structure around the copper ion have been discussed. The ESR parameters of Cu(OEP) doped in Ni(OEP) have been noted to depend significantly upon the polymorphism of the diluent.
Direct Observation of the Type II Biradical and Triplet State of Valerophenone Excited by the Fourth Harmonic of a Nd:YAG Laser
Authors: Hayashi Hisaharu , Nagakura Saburo
Published: July 2006

The Norrish type II reaction of valerophenone was studied by the ns-laser photolysis technique, the fourth harmonic (266 nm) of a Q-switched Nd: YAG laser being used as an exciting light source. Transient absorptions due to the triplet state and 1,4-biradical of valerophenone were observed in both polar and nonpolar solvents. Quenching experiments with cis-1,3-pentadiene were also carried out. Transient absorptions due to the biradical were observed in the 350–300 nm region with the lifetimes of 103 ns (in methanol), 99 ns (in 2-propanol), 71 ns (in acetonitrile), and 31 ns (in 1,2-dichloroethane). Transient absorptions due to the triplet state were also observed in the 440–300 nm region.
Synthesis of Crown Ether Dyes
Authors: Yamashita Toshiro , Nakamura Hiroshi , Takagi Makoto , Ueno Keihei
Published: July 2006

Crown ether dyes were synthesized in order to develop photometric reagents which are highly selective to alkali and alkaline earth metals. They contain dissociable protons attached to the chromophores of crown ether molecule. Their extraction behavior for alkali and alkaline earth metal ions as neutral complex was examined. The dyes extract potassium and alkaline earth metals, respectively. Dyes with picrylamino chromophore are effective for extractive photometric determination of potassium. A molecular design of colorimetric reagents is discussed on the basis of crown ethers.
N-Acylimidazoles–Trifluoroacetic Acid System as the Acylating Agent for Aromatic Hydrocarbons
Authors: Keumi Takashi , Saga Hiroshi , Kitajima Hidehiko
Published: July 2006

N-Benzoylimidazole in trifluoroacetic acid could benzoylate electron-rich aromatic compounds, such as durene, p-dimethoxybenzene, mesitylene, anisole, thiophene, and fluorene, to give the corresponding benzophenone derivatives in good yields. It was further elucidated, in the reaction of fluorene, that N-acylimidazoles composed of a variety of acyl groups also could be used for the ketone synthesis. Therein, the imidazolides of aliphatic carboxylic acids or substituted benzoic acids with an electron-donating group gave ketones in high yields. The above-mentioned aromatic compounds were also acylated with N-trifluoroacetylimidazole and free carboxylic acids in trifluoroacetic acid. The mechanism for these reactions was assumed to proceed via a mixed anhydride between trifluoroacetic acid and carboxylic acid.
Layered Compounds. LXIII. Bromination of Double- and Triple-layered Paracyclophanes
Authors: Otsubo Tetsuo , Horita Hisanori , Koizumi Yosuke , Misumi Soichi
Published: July 2006

[m.m][n.n]Triple-layered paracyclophanes underwent bromination to give exclusively monobromo derivatives substituted to the inner benzene. The reactions were markedly accelerated by the transannular electronic interaction as compared to [n]- and double-layered paracyclophanes, and their enhanced reactivities were demonstrated by some competitive reactions. The relative rates of [2.2] and [3.3]systems are in reverse order for the triple-layered and double-layered series. Their reaction mechanisms were discussed.
The Synthesis of Unsubstituted Crown Ethers by the Reaction of Oligoethylene Glycols with Arenesulfonyl or Alkanesulfonyl Chlorides
Authors: Kuo Ping-Lin , Kawamura Norio , Miki Masaki , Okahara Mitsuo
Published: July 2006

A new facile method of synthesizing crown ethers from oligoethylene glycols by treating them with arenesulfonyl or alkanesulfonyl chlorides in the presence of alkali metal hydroxide or alkoxide was described. 15-Crown-5 and 21-crown-7 were synthesized from pentaethylene glycol and heptaethylene glycol respectively in good yields, while 18-crown-6 was obtained from both hexaethylene glycol and triethylene glycol. Although the main product was 24-crown-8 in the reaction of tetraethylene glycol/TsCl/Na(K)OH in dioxane, 12-crown-4 was obtained in a moderate yield from the reaction of tetraethylene glycol/benzenesulfonyl chloride/t-BuOLi in t-BuOH. Furthermore, the analogous treatment of PEG 200 afforded a mixture of 15-, 18-, 21-, and 24-crown ethers. The reaction conditions were investigated, and the scope of the reaction was discussed.
Chiral Mesophases of 12-Hydroxyoctadecanoic Acid in Jelly and in the Solid State. I. A New Type of Lyotropic Mesophase in Jelly with Organic Solvents
Authors: Tachibana Taro , Mori Tomoko , Hori Kayako
Published: July 2006

Thermally reversible jellies of optically active 12-hydroxyoctadecanoic acid (12HOA) with CCl4 or aromatic solvents form a lyotropic mesophase, which shows enantiomeric circular dichroism (CD) and induced CD due to achiral molecules added to the jellies, indicating that the jellies have a supramolecular helicoidal structure. The X-ray examination revealed that the jellies are composed of a number of small, ordered domains with such a lamellar structure as is observed in the crystalline solid. The supramolecular helicoidal structure was associated with the lamellar structure; as a result, it was suggested that the lyotropic mesophase has a chiral smectic structure and, furthermore, that the mesophase is present in thin, fibrous aggregates of 12HOA molecules within which the jellies are enmeshed.
Hydroxyamidine as a Highly Selective Extractant for Spectrophotometric Determination of Molybdenum with Thiocyanate
Authors: Kharsan Raghunandan Singh , Mishra Rajendra K
Published: July 2006

A highly selective method for the extractive-spectrophotometric determination of molybdenum is described. Molybdenum is reduced with ascorbic acid in strongly acidic media (2.0–4.5 mol dm−3 HCl), and complexed with N1-hydroxy-N1-p-tolyl-N2-(3,4-dimethylphenyl)benzamidine in the presence of thiocyanate. The stoichiometry of mixed complex is found to be 1:2:2 (metal:reagent:thiocyanate). The red-orange molybdenum complex shows a sharp maximum at 470 nm having molar absorptivity 3800 dm3 mol−1 cm−1. All the metal ions associated with a matrix of molybdenum such as Ni(II), Co(II), Cu(II), Mn(II), Ti(IV), Zr(IV), V(V), Nb(V), Ta(V), and W(VI) do not interfere. The applicability of the method has been tested with an ore and various alloys.
The Configuration of the Adsorbed Polymer at the Solid-Liquid Interface as Depicted by ESR and IR Studie
Authors: Sakai Harutoshi , Imamura Yoshio
Published: July 2006

Bound segment fractions of adsorbed poly(methyl methacrylate) on silica in CCl4 were determined by both the spin-labeling technique and infrared spectroscopy. The ESR method yielded considerably larger values than the IR, indicating a highly flattened structure of the adsorbed polymer. However, the greater reliability of the ESR method was pointed out.
The Adsorption of Dodecyldimethylammonium Chloride on Aqueous Surfaces of Concentrated NaCl Solutions
Authors: Ozeki Sumio , Ikeda Shoichi
Published: July 2006

Surface tension of aqueous NaCl solutions of dodecyldimethylammonium chloride has been measured at high NaCl concentrations. Surface excesses of surfactant cation, Na+ and Cl− are derived by means of the Gibbs adsorption isotherm from the derivatives of surface tension with respect to surfactant concentration and NaCl concentration. The rational mean activity coefficients of surfactant and NaCl are both approximated by a common expression satisfying the Brönsted principle for mixed electrolytes but including the ionic strength as a variable. Saturated value of surface excess of surfactant cation remains constant at low NaCl concentrations up to 0.10 M, while it increases as the NaCl concentration exceeds 0.50 M. The adsorption of Na+ is negative at low NaCl concentrations, but it increases rapidly and is positive above 0.50 M NaCl. Surfactant and NaCl are subject to the strong salting-out effect when the NaCl concentration is higher than 0.50 M. The Corrin-Harkins plot of the critical micelle concentration at high NaCl concentrations deviates from the straight line.
Catalysis by Alkaline Earth Metal Oxides. I. The Mechanism of Ethylene Hydrogenation on Calcium Oxide
Authors: Kasama Kaname , Inoue Yasunobu , Yasumori Iwao
Published: July 2006

The mechanism of ethylene hydrogenation on a thermally activated CaO was studied in the overall temperature range of 197–623 K. The maximum in the reaction rate was observed around 320 K, while the activation energy was found to vary with the range of reaction temperatures, i.e., 12.6 kJ/mol (197–273 K) and −16.7 kJ/mol (373–623 K). The partial pressure dependence of the rate was also different in these ranges; the reaction orders with respect to the hydrogen and ethylene pressures were 0.7 and nearly zero at 273 K respectively, whereas the orders shifted to 1.0 and 0.9 at 523 K in the pressure range from 6 to 40 Torr (1 Torr=133.3 Pa). The reaction with deuterium at 523 K produced ethane containing widely distributed deuterium and was accompanied by the formation of highly-exchanged ethylene, HD, and H2 molecules in the gas phase. On the contrary, the reaction at 273 K formed ethane [D2] (>60%) selectively, and the hydrogen-deuterium exchange occurred to a lesser extent in both ethylene and deuterium. By the proposed associative mechanism, the variation in the kinetic behavior with the temperature was explained in terms of the change in the slow step from the reaction between the adsorbed hydrogen and surface ethylene to the hydrogenation of the ethyl radical. The poisoning of the hydrogenation by preadsorbed CO indicated that only 0.5% of the total surface atoms contributed actively to the reaction. On the basis of these results, the structures of active sites are briefly discussed.
X-Ray Photoelectron Spectroscopic Study of Tetrathiafulvalene–Tetracyanoquinodimethane (TTF·TCNQ) and Related High Conductive Organic Complexes
Authors: Ikemoto Isao , Yamada Masamichi , Sugano Tadashi , Kuroda Haruo
Published: July 2006

Tetrathiafulvalene–tetracyanoquinodimethane (TTF·TCNQ) and related high conductive organic complexes were studied by X-ray photoelectron spectroscopy (XPS). The N 1s peak shape of TTF·TCNQ evaporated film was found to change by X-ray irradiation; the high-binding energy shoulder of the N 1s peak increased its intensity with X-ray irradiation time and finally showed a new peak separated by about 1.5 eV from the main peak. TTF·TCNQ was found to be 1:1 both in the surface and in the bulk. The amounts of charge transfer in TTF·TCNQ and other TTF complexes as well as those in 5,6:11,12-bis(dithio)naphthacene(tetrathiotetracene, TTT) complexes were determined from the analysis of the S 2p peak shape. The amount of charge transfer is 0.56±0.05 in TTF·TCNQ and 0.55±0.05 in TTF·TNAP (tetracyanonaphthoquinodimethane). The molecular ratio of (donor)+ in donor molecules is 0.71±0.05 in TTF·Br0.7, 0.52±0.05 in TTF·I0.7, 0.65±0.05 in (TTF)3(BF4)2, 0.49±0.05 in (TTT)2I3, and 0.93±0.05 in (TTT)(TCNQ)2, which correspond respectively to 100, 73, 100, 100, and 100% charge transfer between donors and acceptors. The N 1s peak shape of TTF·TCNQ is also discussed.
Electrochemical Study of Spectral Sensitization Using AgCl Sheet Crystal as a Window. Ag+ Ion Effect
Authors: Sumi Seiichi , Watanabe Tadashi , Fujishima Akira , Honda Kenichi
Published: July 2006

With use of AgCl sheet crystal as a window, sensitized photocurrent was measured in an electrochemical cell with a lock-in amplifier. With five sensitizing dyes having different lowest vacant levels, it was found that the higher the level of the dye, the larger the sensitized photocurrent, the sensitized photocurrent increasing with decreasing pAg of the dye-bearing solution. The Ag+ ion effect can be explained by a band edge shift of the AgCl electrode, which also explains the blue desensitization recovery by Ag+ ions.
Effect of the Phase Transition in Liposomes on the Fluorescence of Amphiphilic Cyanine Dyes
Authors: Onuki Kaoru , Kurihara Kazue , Toyoshima Yoshinori , Sukigara Mitsunori
Published: July 2006

The dependence of fluorescence intensity of amphiphilic cyanine dyes on the thermotropic fluid-solid phase transition of lipid bilayer membranes has been investigated. N,N′-dioctadecyl oxacarbocyanine iodide or N,N′-dioctadecyl thiacarbocyanine bromide was incorporated into single lamellar liposomes, and the fluorescence intensity of each dye was observed to be modified considerably by the phase transition of the lipid bilayers. An amphiphilic cyanine dye with single long alkyl chain, N-octadecyl-N′-methyl thiacarbocyanine bromide was also incorporated in the lipid bilayers, but in this case, the phase transition showed little effect on the fluorescence intensity. These results were interpreted in terms of the effect of the bilayer membrane fluidity and rigidity on the rotational motion of the incorporated cyanine dyes. The phase transition parameters were obtained by applying those amphiphilic dyes as the fluorescence probe of the phase transition of the liposomes.
Asymmetric Hydrogenation with Chiral Aminophosphine–Rhodium Complexes and Chiral Recognition by Bisphosphine–Rhodium Complexes in the Asymmetric Hydrogenation of Olefins through the Chiral Helical Conformation of Phenyl Groups on the Phosphorus Atom
Authors: Onuma Ken-ichi , Ito Tomiyasu , Nakamura Asao
Published: July 2006

The asymmetric hydrogenation of α-acylaminocinnamic acids with the rhodium complex of (1R,2R)-1,2-bis(N-diphenylphosphino-N-methylamino)cyclohexane has been reported to give preferentially (S)-amino acids. On the contrary, it has been found that the enantiomeric (R)-amino acids are obtained by hydrogenation with the rhodium complex of (1R,2R)-1,2-bis(diphenylphosphinamino)cyclohexane. The study of the inversion of the stereoselectivity of the rhodium complex of (1R,2R)-1,2-bis(diphenylphosphinamino)cyclohexane by the N-methylation of the ligand in asymmetric hydrogenation has been described. From stereochemical considerations, the chiral helical conformation of the phenyl groups attached on the phosphorus in bisphosphine-rhodium complexes may be responsible for the induced chirality of the product of the hydrogenation. A complex with a left-handed helicity would give (R)-amino acid, and a complex with a right-handed helicity would give (S)-amino acid. The effects of the solvents and substrate structures on the optical yields are also discussed.
Direct Conversion of Arylamines to the Corresponding Halides, Biphenyls, and Sulfides with t-Butyl Thionitrate
Authors: Oae Shigeru , Shinhama K\={o}ichi , Kim Yong Hae
Published: July 2006

t-Butyl thionitrate have been found to be an excellent diazotizing reagent of arylamines in aprotic nonpolar media, affording eventually such products as aryl chlorides, aryl bromides, aryl iodides, biphenyls, and aryl methyl sulfides in the presence of CCl4, CHBr3, I2, benzene, and dimethyl disulfide, respectively, via extrusion of N2.
Chemistry of N-Thiosulfinylanilines. V. Reactions of N-Thiosulfinylanilines with Nucleophilic Reagents
Authors: Inagaki Yoshio , Hosogai Takeo , Okazaki Renji , Inamoto Naoki
Published: July 2006

2,4-Di-t-butyl-6-methyl-N-(thiosulfinyl)aniline (1) gave 2,4-di-t-butyl-6-methylaniline in the reactions with such reagents as alkylamines, thiourea, butyllithium, alkylmagnesium halides, 1-(1-pyrrolidinyl)cyclopentene, and hydrogen sulfide. Triphenylphosphine reacted with 1 to give (2,4-di-t-butyl-6-methylphenylimino)triphenylphosphorane and bis(2,4-di-t-butyl-6-methylphenyl)sulfur diimide. Reaction of triphenylphosphine with 2,4,6-tri-t-butyl-7,8-dithia-9-azabicyclo[4.3.0]nona-2,4,9-triene afforded 2,4,6-tri-t-butylaniline, bis(2,4,6-tri-t-butylphenyl)sulfur diimide, and 2,4,6-tri-t-butyl-N-sulfinylaniline (7). The sulfur diimide was considered to be formed via intermediary 2,4,6-tri-t-butylthionitrosobenzene, which was trapped by oxygen to give the N-sulfinyl derivative 7.
Isotope Effect of the Glass Transition Temperature of Aqueous Solution. LiCl and ZnCl2 Solutions in Water and D2O
Authors: Kanno Hitoshi , Shirotani Ichimin , Minomura Shigeru
Published: July 2006

Glass transition temperatures of the LiCl and ZnCl2 solutions in both water and D2O were measured as a function of the concentration of the salt. The composition dependence of isotope effect is briefly discussed for these solutions.
The Fifth Overtone Spectra of Aryl C–H Stretching Vibrations in C6H5CH3−nCln
Authors: Mizugai Yoshihiro , Katayama Mikio
Published: July 2006

The fifth overtone frequencies of the aryl C–H vibration of C6H5CH3−nCln were observed by means of the thermal-lens technique. The shifts of their vibrational frequencies from that of benzene were found to be proportional to the inductive contribution of the Hammett σ, thus supplying information on the reactivity of the chemical bond.
Bromophenols from the Red Alga Rhodomela larix
Authors: Suzuki Minoru , Kowata Nobuhiko , Kurosawa Etsuro
Published: July 2006

Two new bromophenols, 3-bromo-4-hydroxybenzaldehyde and a brominated dibenzyl ether derivative, were isolated from the red alga Rhodomela larix, along with several known bromophenols which have previously been isolated from R. larix and other species.
Requirements for an “Organic Metal”
Authors: Saito Gunzi , Ferraris John P
Published: July 2006

Current theories on the origin of high electrical conductivity in TCNQ-based materials emphasize the need for incomplete charge transfer as well as segregated stacks of donor and acceptor molecules and uniform spacing within the stacks. The requirements for an “organic metal” are discussed in terms of partial charge transfer. An examination of 61 structurally related TTF–TCNQ, based complexes suggests that the combinations with the redox potential −0.02≤E1(D)−E1(A)≤0.34 V have a high possibility of being “organic metals.” A method to arrange the complex by the difference between the electrochemical half-wave potentials of the donor and the acceptor molecule is proposed to predict electrical properties of the complex.
Light Scattering Study of Local Structures in Solutions. Cooperative Translational Motion of Alcohol Molecules in Carbon Tetrachloride Solutions
Authors: Kato Tadashi , Ito Nobuyuki , Fujiyama Tsunetake
Published: July 2006

The concept of a “moving unit”—a group of molecules which move together for the time much longer than the velocity auto-correlation time, τ—was introduced in order to obtain information about cooperative translational motions of molecules in associated solution. The mutual diffusion coefficient was theoretically expressed in terms of the self diffusion coefficients and the number of moving units. The theoretical results were applied to the study of the mutual diffusion coefficients for methanol–carbon tetrachloride and ethanol–carbon tetrachloride solutions measured by Rayleigh scattering. It was shown that the mean number of alcohol molecules which constitute a moving unit is much smaller than the mean association number of alcohol, especially in the high concentration range of alcohol. This indicates that the hydrogen-bonded polymer of alcohol molecules cannot move without changing the polymer shape within the time τ.
Ion Pair Formation between Electro-generated 1,2-Naphtoquinone Anion Radicals and Alkali Metal Cations in Acetonitrile
Authors: Fujinaga Taitiro , Okazaki Satoshi , Nagaoka Tsutomu
Published: July 2006

Ion association of 1,2-naphthosemiquinone with the alkali metal cations in acetonitrile has been comprehensively studied by the use of ESR, absorption spectroscopy, polarography and with MO calculation. A continuous flow electrolysis system with a glassy carbon column electrode has been developed for the rapid quantitative preparation of organic free radicals, whose ESR spectrum or absorption spectrum was observed in situ. The formation constants of the ion pair with K+, Na+, and Li+ were estimated as 103.2, 104.5, and 108.0, respectively. By the addition of alkali metal cations, the half-wave potentials shifted to more positive potential in the order of K+<Na+<Li+. The proton hyperfine splitting constants in the ESR also varied in this order. This column electrolysis method is considered to be a powerful technique, particularly for the study of short lived free radicals, because the quantitative electrolysis is performed rapidly even in a solution of extremely diluted supporting electrolyte, such as 0.1 mM (mmol/dm3).
Stereochemistry of Λ-uns-(2S,2S′)-1,1′-Trimethylenedipyrrolidine-2,2′-dicarboxylato Cobalt(III) Complexes with N-Alkyl Substituted Amino or Cyclic Imino Acids
Authors: Okabayashi Minahiro , Okamoto Ken-ichi , Hidaka Jinsai
Published: July 2006

((2S,S′-1,1′-Trimethylenedipyrrolidine-2,2′-dicarboxylato)(α-amino carboxylato)cobalt(III) complexes were prepared and characterized, where the α-amino carboxylate ligand is glycinate, (R)- or (S)-alaninate, (R)- or (S)-valinate, sarcosinate, N-ethylglycinate, (R)-prolinate, or (S)-pipecolate ((S)-2-piperidinecarboxylate). Of the three possible isomers, only the Λ-uns-mer form was prepared for each of the complexes except for the glycinato complex. The (R)-prolinato and (S)-pipecolato complexes were stereoselectively prepared by using (RS)-proline or (RS)-pipecolic acid. The pipecolate ion coordinated selectively was assigned to S(C) configuration on the basis of the CD measurement of the 2,4-dinitrophenyl-pipecolic acid. The nitrogen atom of the sarcosinate, N-ethylglycinate, (R)-prolinate, or (S)-pipecolate ion, which coordinated stereoselectively to Co(III) ion, took the R(N) configuration. The stereoselectivity in this work was discussed on the basis of the electronic absorption, CD, and PMR spectra.
Chiral Recognition in Catalytic Hydrogenation of α-Acylaminoacrylic Acids by Cationic Rhodium(I) Complexes of Chiral Aminophosphines Derived from (R,R)-1,2-Cyclohexanediamine or (R)-1,2-propanediamine
Authors: Kashiwabara Kazuo , Hanaki Kazuhiro , Fujita Junnosuke
Published: July 2006

Four chiral diphosphines, (R,R)-1,2-bis[N-methyl(diphenylphosphino)arnino]cyclohexane, (R,R)-1,2-bis[(diphenylphosphino) amino] cyclohexane, (R)-1,2-bis[N-methyl(diphenylphosphino)amino]propane, and (R)-1,2-bis[(diphenylphosphino)amino] propane have been prepared from the corresponding optically active diamines. The cationic 1,5-cyclooctadiene rhodium(I) complexes with these diphosphines act as effective homogeneous catalysts for the stereoselective hydrogenation of α-acylaminoacrylic acids. The optical yields and the absolute configurations of the products depend on the kind of diphosphine ligands. The (R,R)-1,2-bis[N-methyl(diphenylphosphino)amino]cyclohexane complex catalyst yields N-benzoyl-(S)-leucine, N-benzoyl-(S)-phenylalanine, and N-acetyl-(S)-phenylalanine in 94, 92, and 89% e.e., respectively. The other three catalysts are less effective (6–74% e.e.). The aminophosphine complexes with methyl groups on the nitrogen atoms always give (S)-amino acids, those with no methyl group (R)-amino acids. Such a difference in the chiral recognition has been discussed on the basis of circular dichroism spectra and Dreiding molecular models of the rhodium(I) complexes.
The Use of Grignard Reagents in the Synthesis of Carbohydrates. II. The Cleavage of Acetal Protecting Groups in Sugar Derivatives
Authors: Kawana Masajiro , Emoto Sakae
Published: July 2006

The selective reaction of acetal protecting groups in sugars with Grignard reagents is described. The treatment of 1,2:5,6-di-O-cyclohexylidene-α-d-glucofuranose (1) with methylmagnesium iodide in benzene-ether at about 85 °C gave 1,2-O-cyclohexylidene-6-O-(1-methylcyclohexyl)-α-d-glucofuranose. When isopropylmagnesium iodide or t-butylmagnesium bromide was used instead of methylmagnesium iodide, 1 gave 1,2-O-cyclohexylidene-6-O-(cyclohex-1-enyl)-α-d-glucofuranose and the corresponding 6-O-cyclohexyl derivative. The selective cleavage of the acetal protecting groups in some other sugars with the Grignard reagents is also described.
The Solvent Extraction of Alkali Metal Picrates by 12-Crown-4
Authors: Takeda Yasuyuki
Published: July 2006

The overall extraction equilibrium constants (Kex) for 1: 1: 1 complexes of 12-crown-4 (12C4) with alkali metal picrates between benzene and water have been determined at 25 °C. The Kex series for the 12C4 for the alkali metal ions are given by Na+>Li+>K+>Rb+≥Cs+.
Photo-CIDNP Observed in O-Methylbenzoin–Carbon Tetrachloride System
Authors: Maruyama Kazuhiro , Furuta Hiroyuki , Otsuki Tetsuo
Published: July 2006

Photo-induced decomposition of O-methylbenzoin in carbon tetrachloride was investigated. A reaction scheme is proposed with the aid of photo-CIDNP technique and product analysis.
The Reactions of NH(a1Δ) with Ethane, Propane, and Isobutane in the Liquid Phase
Authors: Tsunashima Shigeru , Hamada Jun-ichi , Hotta Mitsuhiro , Sato Shin
Published: July 2006

The photolysis of HN3 was studied in liquid ethane, propane, and isobutane at the temperature of Dry Ice–methanol. In the reaction mixtures, quaternary ammonium salts were formed between the basic products and HN3. The products were analyzed after having been passed through a trap containing NaOH, in which the salts were decomposed. The main products observed were nitrogen and amines: ethylamine from ethane, propyl– and isopropylamine from propane, and i-butyl, and t-butylamine from an isobutane solution. Ammonia and hydrogen were also formed as minor products. Possible reaction mechanisms are discussed. It is suggested that about 80% of the singlet NH is inserted into the C–H bond of paraffin to form amine and that 20% of it is deactivated to the ground triplet state by the reactions with paraffin. The relative efficiencies of the insertion into primary, secondary, and tertiary C–H bonds were estimated to be 1.0, 1.9, and 2.3 respectively.
Some New Relationships between the Molecular Electron Densities and the Intensities of Electrons and X-Rays Scattered by Gases
Authors: Sasaki Yorihiko , Konaka Shigehiro , Kimura Masao
Published: July 2006

Some new relations connecting the molecular electron densities and the intensities of electrons and X-rays scattered by gases have been derived by integrating analytically the scattered intensities multiplied by some functions of the momentum transfer, s, over ds.
Observation of Intramolecular Excimer Emission of Benzyl Radical Pair Produced by Photolysis of [2.2]Paracyclophane
Authors: Ishikawa Shun-ichi , Nakamura Junko , Nagakura Saburo
Published: July 2006

Photochemistry of [2.2]paracyclophane in glassy solvents at 77 K was studied. With irradiation, a species in which two benzyl radicals are linked together with an ethylene bridge was produced. From the ESR study, the radicals were found to form the benzyl radical pair in harder solvents. The emission spectrum and the emission lifetime of the radical species showed remarkable dependence on the solvent viscosity. In harder solvents, a new broad emission was observed on the longer wavelength side of the structured emission of the benzyl radical. From the studies of the excitation spectrum and the emission lifetime, this broad band was concluded to be the intramolecular excimer fluorescence of the radical pair. The photo-reaction of [2.2]paracyclophane was found to be biphotonic, occurring from a higher triplet state excited via the lowest triplet state.
A New Synthesis of 1-Amino-4-butylaminoanthraquinone from 1-Aminoanthraquinone Promoted by Metal Ions
Authors: Yoshida Katsuhira , Matsuoka Masaru , Yamashita Yoshio , Kitao Teijiro
Published: July 2006

In the presence of some metal ions and atmospheric oxygen, 1-aminoanthraquinone(1) reacts readily with butylamine to give 1-amino-4-butylaminoanthraquinone(2a), along with a small amount of 1,4-diaminoanthraquinone, which is produced by the dealkylation of 2a. The activity of the metal ions decreased in the following order: Co(II)>>Ni(II)>Cu(II)>Al(III). The reaction is remarkably affected by the substitution of an alkyl group into the amino group of 1, the addition of a chelating agent, the counter anion of metal ions, and the reaction temperature. By the use of cobalt(II) chloride, the reaction proceeds most smoothly at about 30 °C. Both anthraquinone and 2-aminoanthraquinone show no sign of the reaction under the same conditions. A possible mechanism involving the formation of a metal complex, followed by the nucleophilic attack of amine at the 4-position and the oxidative abstraction of the hydride anion by atmospheric oxygen is proposed.
Synthesis of Muramyl Dipeptide Analogs with Enhanced Adjuvant Activity
Authors: Kobayashi Shigeru , Fukuda Tsunehiko , Yukimasa Hidefumi , Fujino Masahiko , Azuma Ichiro , Yamamura Yuichi
Published: July 2006

N-Acetylmuramyl-l-alanyl-d-isoglutamine (MDP) and thirteen new analogs were synthesized by the conventional organic chemical procedure using dicyclohexylcarbodiimide-N-hydroxy-5-norbornene-2,3-dicarboximide as a coupling agent. Their ability to induce delayed-type hypersensitivity to N-acetyl-3-(4-arsonophenylazo)-l-tyrosine in guinea pigs was assayed. The results indicate that the presence of an α-amino acid adjacent to the lactic acid moiety in MDP is important for the high biological activity, the valine analog having the most favorable effect. The structure-activity relationship is discussed.
The Crystal Structure of Bis(acetylacetonato)platinum(II)
Authors: Onuma Shigeki , Horioka Keiji , Inoue Hironao , Shibata Shuzo
Published: July 2006

The crystal structure of Pt(acac)2 has been determined by means of X-ray diffraction. The molecule is monomeric, the coordination geometry being squareplanar. The average Pt–O distance is 1.991(8) Å. The bond lengths and angles of the chelating ligands are almost the same as those for other acetylacetone complexes.
Improved Resonance Energies of Nonalternant Hydrocarbons. An ω-Technique Approach
Authors: Aihara Jun-ichi
Published: July 2006

The ω-technique of Wheland and Mann was introduced into the graph theory of aromaticity in order to improve the resonance energies of nonalternant hydrocarbons. For these compounds, the ω-technique resonance energy was more or less smaller than the resonance energy calculated on the basis of the simplest Hückel MO model. Especially, several compounds thus far considered to be aromatic were predicted to be substantially olefinic with much reduced resonance energies. They are calicene, sesquifulvalene, azulene, dibenzo[cd,gh]pentalene, and cyclohepta[def]fluorene. Many aspects of their chemistry were evidently consonant with the improved resonance energies. Possible limitation of the use of electrophilic substitution as a criterion of aromaticity was discussed. Resonance energies of alternant hydrocarbons are not modified by application of the ω-technique.
The rs Structures of Fluoromethyl, Chloromethyl Ethers, and Methyl 2-Propynyl Ether
Authors: Hayashi Michiro , Kato Hiroshi
Published: July 2006

18O enriched samples of chloromethyl methyl ether and chloromethyl ethyl ether were prepared and their microwave spectra were measured. The rS structures of fluoromethyl methyl ether, fluoromethyl ethyl ether, chloromethyl methyl ether, chloromethyl ethyl ether, and methyl 2-propynyl ether were re-evaluated from the observed rotational constants obtained under the common constraints and assumptions on the structures of the molecules. A comparison of the rS structures was made between the five molecules and between the molecules and their related molecules.
Complexes between Nucleotide Base and Amino Acid. IV. Crystal and Molecular Structure of Cytosine : N,N-Phthaloyl-Dl-glutamic Acid Complex Dihydrate
Authors: Takenaka Akio , Ohki Minoru , Sasada Yoshio
Published: July 2006

Crystals of cytosine: N,N-phthaloyl-Dl-glutamic acid complex dihydrate were obtained from an aqueous solution of the two components. The space group is P21/c with unit-cell dimensions of a=5.243(1), b=39.133(6), c=9.192(1) Å, β=93.66(1)°, and Z=4. The structure was solved by the direct method and its parameters were refined by a block-diagonal least-squares method. The complex is formed by the two hydrogen bonds between the oxygen atoms of the ionized α-carboxyl group of glutamic acid and the nitrogen atoms, N(4) and protonated N(3), of cytosine. This binding mode is the same as that found in cytidine: N-benzyloxycarbonyl-l-glutamic acid complex, but quite different from that of 5-bromocytosine: N-acylglutamic acid complexes. The substituted bromine atom at C(5) of cytosine is thought to prescribe the binding mode in complex formation. The binding mode between cytosine and glutamic acid, which might be a possible elementary pattern of protein: nucleic acid interactions, is discussed in terms of dissociation constant.
An On-line Automated Adiabatic Calorimeter in the 13–300 K. Heat Capacity of Cyclohexanol
Authors: Kishimoto K\={o}ji , Suga Hiroshi , Seki Syûzô
Published: July 2006

A computerized adiabatic calorimeter system operating in the temperature range 13–300 K is described. A digital voltmeter is used for energy measurement and the duration of energy input is determined by a program unit operated by 1 Hz pulse. Temperatures of the calorimeter are measured by a 25 Ω platinum resistance thermometer and an automated ac double bridge. The measured resistance is converted into temperature (IPTS-68) by a calibration table stored in a mini-computer. Criterion for the realization of thermal equilibration is that a temperature drift calculated from the latest six data becomes smaller than a preset value, usually 7×10−8 Ω s−1. The system is able to measure the heat capacity of solid and liquid in an intermittent heating mode and gives the computed results during measurement. Some examples of the test runs on cyclohexanol crystal are shown and the results are compared with those obtained by manual measurements by use of dc Müller bridge. A relaxational heat capacity anomaly observed in glassy crystalline state of cyclohexanol is discussed in correlation with a secondary relaxation observed by previous dielectric measurement.