bluuebunny/crossref_metadata_2025 huggingface dataset:
Syntheses of Isoprenoids by Telomerizations. IX. Stereoselectivity of Telomers and the Effect of Telogens in Anionic Telomerizations Using Secondary Amines
Authors: Takabe Kunihiko , Katagiri Takao , Tanaka Juntaro
Published: July 2006

The stereoselectivity of the telomers and the effect of the telogens in the anionic telomerizations of isoprene with secondary amines were investigated. Dimethyl-, diethyl-, di-n-propy-1, diisopropyl-, and methylphenyl-amines, pyrrolidine, morpholine, and piperidine were used as the telogens. The ratio of N,N-dialkyl(3,7-dimethyl-2,6-octadienyl)amine(2A) to N,N-dialkyl(2-isopropenyl-5-methyl-4-hexenyl)amine(2B), which were obtained in these reactions, was varied with the sort of secondary amines, the yield of the telomers was found to be dependent on the acidity of the secondary amines. Moreover, 2A, which was the main component of the n=2 telomers, was confirmed to have a cis-configuration—that is, N,N-dialkylnerylamine. However, the n=1 telomer of myrcene with secondary amine was N,N-dialkylgeranylamine. These results were interpreted in terms of the stability of the cyclic intermediate of the carbanions.
Modified CNDO 2 Calculations of Ionization Potentials for Some Unsaturated Hydrocarbons
Authors: Ohno Koichi , Hirooka Tomohiko , Harada Yoshiya , Inokuchi Hiroo
Published: July 2006

The orbital energies of several unsaturated hydrocarbon molecules have been calculated using a modified CNDO/2 method, with the electron repulsion integrals evaluated from Klopman’s formula and the σ–π separation factor proposed by Tinland and Jaffé. The empirical parameters are determined to reproduce the observed ionization potentials for ethylene and benzene via Koopmans’ theorem. The results are shown to agree well with the available experimental ionization potentials and with the assignments of the photoelection spectra.
Metal Chelates of Aromatic o,o′-Dihydroxyazo Compounds. I. The Fluorescence Properties of the Metal Chelates of o,o′-Dihydroxyazobenzene and Their Use in Fluorometry
Authors: Hiraki Keiz\={o}
Published: July 2006

As fluorometric reagents for the determination of Al, Ga, In, etc., 11 derivatives of o,o′-dihydroxyazobenzene were examined in an attempt to determine the most desirable structure of azo compounds. o,p,o′-Trihydroxyazobenzene type compounds were more sensitive than o,o′-dihydroxyazobenzene; CH3O-group substitution at the para position was also efficient. The SO3H substitution increased, whereas the Cl substitution decreased the fluorescence of metal complexes, and the CH3-substituted compound did not form fluorescent metal complexes because of its low solubility in water and because of the steric hindrance. Superchrome Garnet Y and Lumogallion seemed to be excellent fluorometric reagents for Al and Ga; 2-(2,4-dihydroxyphenylazo)-1-hydroxybenzene and 3-(2-hydroxy-4-methoxyphenylazo)-4-hydroxybenzene sulfonic acid were also useful. Therefore, the several conditions for the fluorometric determination of Al and Ga with those compounds were also investigated.
The Infrared Spectra and Normal Coordinate Treatments of X3M–Mn(CO)5(X=Cl, Br, and I; M=Si, Ge, and Sn). II.
Authors: Onaka Satoru
Published: July 2006

The infrared absorption spectra (2200–50 cm−1) have been measured for four metal-metal bonded molecules, Cl3Si–Mn(CO)5, Cl3Ge–Mn(CO)5, Br3Ge–Mn(CO)5, and I3Sn–Mn(CO)5. Vibrational normal coordinate analyses have been made for each of these molecules on the basis of a modified Urey-Bradley force-field. The calculated frequencies agree closely with validly-assigned frequencies. The metal-metal stretching force constant, K(M–Mn), or the F-matrix element, f(M–Mn), varies with the halogen atom, and increases as the electronegativity of X increases. The force constant, K(M–Mn), or f(M–Mn) depends also on the IVb metal atom, and increases in the order of: K(Si–Mn)≥K(Ge–Mn)>(Sn–Mn), or f(Si–Mn)≥f(Ge–Mn)>f(Sn–Mn). However, there is no clear relationship between the electronegativity of M and the K(M–Mn) or (M–Mn). These dependences of K(M–Mn) or f(M–Mn) on X and M are discussed, along with the bonding implications of the M–Mn bonds, on the basis of the sets of the force constants, or the sets of the F-matrix elements, and are interpreted in terms of the predominant σ-bonding framework of the M–Mn bonds.
The Kinetics of Oxygen Exchange between Arsenate Ions and Solvent Water
Authors: Okumura Akiko , Okazaki Nobukazu
Published: July 2006

The rates of oxygen exchange between arsenate ions and water have been measured at 14.5 °C and 30 °C over the pH range of 6.5–12.5. The rate, R, may be expressed by the rate law:

R=k_1[H_2AsO_4^-]+k_2[HAsO_4^2-]+k_3[AsO_4^3-]+k_4[H_2AsO_4^-]^2+k_5[H_2AsO_4^-][HAsO_4^2-]+k_6[HAsO_4^2-]^2.

The exchange rates at 30 °C and I=0.55 have been analyzed in terms of this rate law to obtain the values of the rate constants, k1–k6. The activation energy of the over-all exchange reaction is 13.2±0.2 kcal/mol at pH 7.51 and 22.14±0.02 kcal/mol at pH 9.79. The reaction shows a negative salt effect in the region of pH 7.5, and a positive salt effect at pH 9.3.
The Effects of Doubly-excited Configurations in the P-P-P-CI Calculation
Authors: Shinoda Hiroyuki , Tatematsu Hidenobu , Miyazaki Tomoo
Published: July 2006

The effects of doubly-excited configurations, especially of the χk1mn type, on the results of P-P-P-CI calculations of unsaturated compounds have been discussed by comparing the results obtained by three different types of CI treatment. The calculations of the pi-electronic total energies of ground states, the electronic transition energies, the oscillator strengths, and the pi-electronic densities of sixteen molecules were performed. The core resonance integrals and electronic repulsion integrals were readjusted so that the transition energies, obtained by CI calculations considering all the singly- and doubly-excited configurations, might coincided with the experimental results. From the results of these calculations, it is found that χk1mn-type configurations play an important role in CI calculation.
Calorimetric Study of the Glassy State. VIII. Heat Capacity and Relaxational Phenomena of Isopropylbenzene
Authors: Kishimoto Koji , Suga Hiroshi , Seki Syûzô
Published: July 2006

The heat capacities of isopropylbenzene were measured with an adiabatic calorimeter for the crystal from 14 to 177.13 K (Tm), for the glassy state from 14 to around 126 K (glass transition temperature: Tg) and for the liquid from Tg to 313 K, with a sample of 99.93% purity. The heat and entropy of fusion were found to be 7326 J mol−1 and 41.36 J K−1 mol−1, respectively. Based on these data, a set of thermodynamic functions are tabulated at rounded temperatures. In addition to the primary glass transition phenomenon, a secondary enthalpy relaxation as well as a step-like heat capacity anomaly was observed at around 70 K. These facts were discussed in correlation with the β-relaxation already observed by dielectric measurement. Gonfigurational entropies of the supercooled liquid and of the glassy state were calculated to investigate a relation with relaxational properties. The agreement is found between the temperatures where catastrophe occurs in viscosity (T0), and where the configurational entropy vanishes (T2). Finally, a kind of heat capacity break observed in the liquid state is discussed against the view that this behavior is compatible with a third-order thermodynamic transition.
The Electrification of Iron Oxide in Water
Authors: Morimoto Tetsuo , Kittaka Shigeharu
Published: July 2006

The electrification of iron oxides pretreated at various temperatures from 600 to 1200 °C has been investigated in water by measuring the ζ-potential as a function of the pH. From the surface-chemical point of view, iron oxides pretreated at temperatures lower than 800 °C behave differently from those pretreated at higher temperatures ; the isoelectric point of the former samples reaches an equilibrium value in a few hours, while that of the latter samples increases slowly to an equilibrium value with an increase in the surface hydration. On the other hand, the equilibrium isoelectric point of iron oxide decreases sharply upon heat treatment at 800–1000 °C, corresponding to the change in the chemical composition of iron oxide from Fe2O3 to Fe3O4.
The Alkylation of 3,5-Dimethylisoxazole
Authors: Kashima Choji , Tobe Shinji , Sugiyama Noboru , Yamamoto Makoto
Published: July 2006

3,5-Dimethylisoxazole (1) was alkylated with sodium amide in liquid ammonia to give 3-methyl-5-alkylisoxazoles. By di- and tri-alkylation reactions using excess sodium amide, isoxazoles having secondary and tertiary alkyl groups at 5-position could be obtained. The hydrogenolysis and hydrolysis of these isoxazoles were also studied.
Kinetic Studies of the Nickel Lactate Complex Formation in Solution by the Pressure-jump Method
Authors: Harada Shoji , Tanabe Hideyuki , Yasunaga Tatsuya
Published: July 2006

The nickel lactate complex formation reaction in an aqueous solution was studied by the pressure-jump method and the overall rate constants, the stability constants, and the activation parameters were determined. The results were interpreted by the use of the step-by-step complex formation mechanism, and it was revealed that the rate-determining step is the chelate-ring formation process. The ligand effect on the rate of the complex formation was also considered.
Catalytic Decomposition of Stable Sulfur Ylids
Authors: Matsuyama Haruo , Minato Hiroshi , Kobayashi Michio
Published: July 2006

In the presence of dimethoxy disulfide, such stable sulfur ylids as Me2S+–C−(COOMe)2, Me2S+–C−(CN)2, and Me2S+–C−HCOPh were found to decompose at 35 °C, forming methyl sulfide and an olefin or a cyclopropane. Thiocyanogen and trifluoromethyl disulfide were found to possess similar catalytic activity. The scope and mechanism of these reactions are discussed.
The Reflection Spectra of Simple Salts of the Tetracyanoquinodimethane Anion Radical
Authors: Oohashi Yukako , Sakata Tadayoshi
Published: July 2006

The reflection measurements were carried out for fourteen simple salts of the tetracyanoquinodimethane (TCNQ) anion radical over the range from 5000 to 42000 cm−1 by Avery’s method. The solid-state spectra show three bands (CT, YI, and YII) and exhibit distinct differences depending on the cation species. According to the differences in the transition energy (σi) and the oscillator strength (fi), the fourteen salts were classified into three groups (A, B, and C). The solid-state spectra of Group A resemble that of the dimer in an aqueous solution. Group B is characterized by the red shift of the CT band and the intensity increase in the YII band. The spectra of Group C exhibit a vibrational structure in the YI band which is similar to the monomer spectrum in an aqueous solution. Moreover, the large dispersion of the refractive index and the intensity increase in the bands of local excitation were observed for Group C. The electronic structures of these groups were studied by the use of the composite-system method. By taking account of the crystal structure of RbTCNQ-I, belonging to Group A, the stabilization energy (J*) of the ground state was calculated from σCT and fCT. The J* values for ten salts in Group A correspond well to the singlet-triplet separation in the ground state observed by ESR measurements.
The Electronic Spectrum of p-Benzosemiquinone Anion in Aqueous Solution
Authors: Fukuzumi Shun-ichi , Ono Yoshio , Keii Tominaga
Published: July 2006

The electronic spectrum of p-benzosemiquinone anion in aqueous solution formed through the oxidation of hydroquinone with manganese dioxide was measured at room temperature. The absorption maxima were found at 430, 404, and 316 mμ with shoulders at 371 and 310 mμ. It was confirmed that these absorption maxima are due to the same species p-benzosemiquinone anion, on the ground that their kinetic behaviors are the same. The molar extinction coefficients of the absorption maxima and the oscillator strengths of the absorption bands were estimated.
Dielectric Relaxation and Molecular Structure. VII. Structure of the Molecules of Diphenylene Dioxide Type
Authors: Koga Yoshinori , Takahashi Hiroaki , Higasi Keniti
Published: July 2006

The dielectric constants and losses of diphenylene dioxide, phenoxathiin, thianthrene, xanthene and pheno-thiazine have been measured in dilute solution of benzene at the millimeter-wave frequency of 100 GHz at 20 °C. Diphenylene dioxide is found to have a very small dielectric relaxation time which is associated with the change in dipole orientation by the intramolecular change (butterfly motion). The dipole moment of this molecule is small but not considered to be zero. Similar to thianthrene, which has a folded structure about the S–S axis, diphenylene dioxide is also folded about the O–O axis or can easily have a folded structure. Phenoxathiin and the other two molecules have a folded structure and the dielectric relaxation times (at 100 GHz) reveal the effect of the butterfly-flapping motion associated with the barrier height for this internal motion.
Radical Formation Initiated by the Biphotonic Excitation of Acridone
Authors: Miyashita Yoshikatsu , Niizuma Shigeya , Kokubun Hiroshi , Koizumi Masao
Published: July 2006

The photochemical formation of alcohol radical has been found to occur in the rigid solvent of ethanol (77 K) and in the polyvinyl alcohol (PVA) film (77 K and at room temperature), when acridone is dissolved as a sensitizer. It has been established that by absorbing two photons stepwise acridone gives rise to radicals which abstract hydrogen atoms from alcohol molecules, this being called the radical reaction mechanism and abbreviated as R-R mechanism. The energies necessary for the radical formation were estimated by determining energy levels of acridone and examining the wavelength dependence of the reaction. They differed for ethanol (77 K), PVA (77 K) and PVA (room temp.), perhaps due to the cage effect. The feature of the R-R mechanism has been compared with that of the energy transfer type (E-T mechanism) in which the energy is transferred from the higher triplet of solute to solvent molecules. When methyl iodide with a lower dissociation energy is added to an ethanol solution of acridone (77 K) and is then irradiated by an exciting light ineffective for R-R mechanism, methyl radical is formed by E-T mechanism. When the two types of reaction were energetically possible, E-T mechanism occurred more easily than R-R mechanism.
The Preparation and Absorption Spectra of the Mixed cis-Dicyano Complexes of Cobalt(III) with Carbonato or Related Ligands
Authors: Fujinami Shuhei , Shibata Muraji
Published: July 2006

By the reaction of the [Co(CO3)3]3− complex and KCN, the complex anion, [Co(CN)2(CO3)2]3−, has been isolated as the tris(ethylenediamine)cobalt(III) salt. From this dicarbonato-complex anion, related dicyano complexes, [Co(CN)2(CO3)(C2O4)]3− and [Co(CN)2(C2O4)2]3− have then been obtained as Λ(+)589-[Co(en)3]3+ salts, with resolutions into the active forms. Other related complexes, [Co(CN)2(dtc)2]− and [Co(CN)2(xan)2]−(dtc=dimethyldithiocarbamate anion, xan=methylxanthate anion), have also been prepared as potassium salts from the dicarbonato complex. The absorption spectra of all of the dicyano complexes have been measured, as have the CD spectra of the resolved dicyano complexes. Based on these spectral data, the geometrical structures of all the dicyano complexes have been identified as of the cis form. The [Co(CN)(malo)2OH2]2− complex has been isolated as potassium salt. From the PMR spectrum, the structure has been determined as the trans form. The polarized spectra of a crystal of this complex have also been measured.
Layered Compounds. XV. Synthesis and Properties of Multilayered Cyclophanes
Authors: Otsubo Tetsuo , Mizogami Shigeyoshi , Otsubo Ikuko , Tozuka Zenzaburo , Sakagami Akiko , Sakata Yoshiteru , Misumi Soichi
Published: July 2006

A series of multilayered cyclophanes up to sixfold were synthesized by 1,6-Hofmann elimination method. Odd layered and some dissymmetric ones were derived by means of cross-breeding pyrolysis of mixed quaternary ammonium hydroxides. The electronic spectra, absorption, emission, and CT absorption of charge-transfer complexes, of these cyclophanes exhibited remarkable transannular π-electronic interaction among chromophores closely stacked by methylene bridges. The interaction is increased eminently when the layer is varied from single to quadruple, but becomes less effective from quadruple to fivefold and no longer appreciable for more than fivefold one.
Application of the Mannich Reaction to 1-Azaazulan-2-one. Syntheses of Seven-Membered Analogues of Tryptophan and Related Compounds
Authors: Sato Akira , Nozoe Shigeo , Toda Takashi , Seto Shuichi , Nozoe Tetsuo
Published: July 2006

Application of the Mannich reaction to 1-azaazulan-2-one (I) gave 3-dimethylamino-1-azaazulan-2-one (III) in a good yield. Tryptophan analogue and related compounds having this structure (I) were synthesized by the reactions of the quaternary base (VI) of III with potassium cyanide and diethyl acetylaminomalonate. Also, some other reactions of III and VI are reported.
The Polymerization of α-Naphthylmethylvinylether and 3-Pyrenylmethylvinylether and Electrical Conductivity of Their Polymers
Authors: Yoshimoto Shigeki , Okamoto Kenichi , Hirata Hirotaka , Kusabayashi Shigekazu , Mikawa Hiroshi
Published: July 2006

A new vinylmonomer with a large pendant π-electron group was synthesized. α-Naphthylmethylvinylether and 3-pyrenylmethylvinylether were polymerized in good yields, although their polymers have fairly low molecular weights. Both polymers have a fairly high isotacticity. Poly-3-pyrenylmethylvinylether showed a large photocurrent in its absorption region and a small photocurrent even above 500 to 1000 mμ. The doped TCNE significantly sensitized its photoconductivity.
Polarized Absorption Spectra of Single Crystals of Ion Radical Salts. III. Temperature Dependence of the Crystal Spectra of Potassium-Chloranil
Authors: Hiroma Shoji , Kuroda Haruo
Published: July 2006

The polarized absorption spectra in the 10000–37000 cm−1 region were observed on the single crystal of the water-free modification of the potassium-chloranil salt, K+·(chloranil)−, by using a microspectrophotomer, and the variation of the spectra with temperature was examined. The crystal gives a near-infrared absorption band associated with the charge transfer between chloranil radical anions, the maximum of which is located at 11.5×103 cm−1. The absorption bands in the 20000–37000 cm−1 region were assigned to the local-excitation bands associated with the transitions in the chloranil anion. The intensity of the charge-transfer band gradually increases on lowering the temperature. An abrupt increase of intensity occurrs in the charge-transfer band at the phase-transition point. There is a close correlation between this change and the temperature dependence of the paramagnetic susceptibility of the salt.
The Photo-Erasable Memory Switching Effect of Ag Photo-Doped Chalcogenide Glasses
Authors: Shimizu Isamu , Kokado Hiroshi , Inoue Eiichi
Published: July 2006

The electric conductivity of the chalcogenide glass increased with an increase in the amount of Ag which had been photo-doped. By applying the electric field to the electrodes which were set on the surface of the Ag photo-doped chalcogenide glass film, a conductive path was grown from the cathode to the anode. As a result of the connection of the electrodes with the path, the electric resistance of the cell abruptly decreased (ON state). The path was made of the metal silver reduced by electrolysis and was diminished by irradiation with light. As the path was erased, the cell was turned into the resistant state (OFF state). The cycles were repeatable many times. There was a delay time (td) in turning the cell from the OFF to the ON state by applying the electric field (E). It was empirically described by the following equation for the Ag photo-doped chalcogenide glasses:

t_d=aexp(-b·E)
The Cadmium-photosensitized Decomposition of Acetaldehyde, Propionaldehyde, and n-Butyraldehyde
Authors: Yamamoto Koji , Tsunashima Shigeru , Sato Shin
Published: July 2006

The reactions of acetaldehyde, propionaldehyde, and n-butyraldehyde photosensitized by cadmium (3P1) have been investigated at 270 °C. The pressure dependence of the main products, CO, RH (R=CH3, C2H5, and n-C3H7) and R2, was well explained by the following reaction mechanism; Cd*+RCHO→R+CHO+Cd or RH+CO+Cd. R+RCHO→RH+RCO, RCO→R+CO, CHO→H+CO, H+RCHO→H2+RCO, R+R→R2 or RH+ Olefin. Carbon dioxide was found to be a rather good quencher for triplet cadmium atoms, and was used for estimating the relative quenching efficiencies of the three aldehydes and acetone. The values obtained were 0.16, 1.0, 1.3, 1.2, and 1.4, respectively for carbon dioxide, acetone, acetaldehyde, propionaldehyde, and n-butyraldehyde, when the efficiency of cis-2-butene was assumed to be unity.
Far Infrared and Raman Spectra of K3[Co(CN)6] and [Co(NH3)6][Co(CN)6]
Authors: Nakagawa Ichiro
Published: July 2006

Far infrared spectra of K3[Co(CN)6] and [Co(NH3)6][Co(CN)6] and a single crystal Raman spectrum of K3[Co(CN)6] have been measured. Calculations of optically active crystal vibration frequencies have been made, on the basis of the crystal structure determined precisely. For these two types of established crystal structures (C2h5 for K3[Co(CN)6] and C3i2 for [Co(NH3)6]) [Co(CN)6] of hexacyano-complex salts, lattice frequencies have been determined. For [Co(NH3)6][Co(CN)6] the mean amplitudes of two kinds of cobalt atoms have been calculated and compared with those obtained by Iwata and Saito assuming that both complex ions behave as a rigid body.
Copper(II) Complexes with Some Aliphatic Diaminealcohols
Authors: Ishimura Yasuo , Nonaka Yasuomi , Nishida Yuzo , Kida Sigeo
Published: July 2006

Copper(II) complexes were prepared with a series of tridentate ligands, NH2(CH2)mCHRNH(CH2)n OH (R=H or CH3; m=1 or 2; n=2 or 3). Compounds obtained can be classified into three groups: (1) CuLCl2, (2) CuL(ClO4) and (3) CuL2X2, (L and L′ represent the neutral and the anionic ligands, respectively, and X denotes Cl or ClO4). (1) and (3) were found to be mononuclear in which L functions as a bidentate ligand donating with the two nitrogen atoms. (2), except for the complex with L′=NH2(CH2)3NH(CH2)2O− have the binuclear structure with alkoxo bridges. The absorption bands at about 350 nm are characteristic of the binuclear structure with alkoxo or hydroxo bridges.
Stability of Fused Rings in Metal Chelates. XI. Stability of Dipeptide Amide-Copper(II) Complexes
Authors: Yamauchi Osamu , Nakao Yasuo , Nakahara Akitsugu
Published: July 2006

The structure-stability relationship between the copper(II) complexes of several dipeptide amides consisting of glycine and/or β-alanine has been investigated by potentiometric titration. The amides of glycylglycine, glycyl-β-alanine, and β-alanylglycine (abbreviated as H2L) have been found to form complexes of the type Cu(H2L)2+ with logK1 values 4.80–5.22. The −logKC1 values for deprotonation of the peptide group are 5.05–5.42 and comparable to those of tripeptides, whereas the −logKC2 values for the terminal amide group are 7.96 for glycylglycine amide and 8.99 for glycyl-β-alanine amide. This indicates that, at neutral pH, the –CONH2 group coordinates to copper(II) mainly through the carbonyl oxygen. β-Alanyl-β-alanine amide-copper(II) system gave precipitates at an early stage of titration. The structures and relative stability of the complexes of types Cu(H2L)2+, Cu(HL)+, and CuL have been discussed from comparative studies of their stability constants.
The Analytical Application of Sulfur Analogues of β-Diketones. III. The Separation of Cobalt(II), Nickel(II), Copper(II), Zinc(II), Mercury(II), Lead(II), and Cadmium(II) as Their STTA (1,1,1-Trifluoro-4-(2-thienyl)-4-mercapto-3-buten-2-one) Complexes by Thin-layer Chromatography on Silica Gel
Authors: Honjo Takaharu , Kiba Toshiyasu
Published: July 2006

Cobalt(II), nickel(II), copper(II), zinc(II), mercury(II), lead(II), and cadmium(II) were extracted with STTA (1,1,1-trifluoro-4-(2-thienyl)-4-mercapto-3-buten-2-one) in cyclohexane, and their colored complexes were chromatographed on a thin-layer of silica gel with various organic solvents. The developing solvents used were 18 kinds of pure solvents and 10 different binary solvent mixtures of 1 :1, v/v. An excellent separation could be achieved after development with carbon tetrachloride, carbon disulfide, ethyl acetate, and cyclohexane–chloroform, chloroform–carbon disulfide, and carbon tetrachloride–carbon disulfide mixtures. The Rf value generally increased in the following orders: Cd(II), Zn(II), Pb(II), (STTA)<Hg(II)<Co(II, III)<Cu(II)<Ni(II) (with carbon tetrachloride); Cd(II), Zn(II), Pb(II), (STTA)<Co(III)<Hg(II)<Cu(II)<Ni(II) (with carbon disulfide); Cd(II), (STTA)<Zn(II)<Pb(II)<Hg(II), Co(III), Cu(II), Ni(II) (with ethyl acetate); and Cd(II), Zn(II), Pb(II), (STTA)<Hg(H)<Co(III)<Cu(II)<Ni(II) (with the cyclohexane-chloroform, chloroform-carbon disulfide, and carbon tetrachloride–carbon disulfide mixtures). A few μg Ni(STTA)2 chelates on the plate could be determined quantitatively by measuring the spot area from the curve drawn on a millimeter-graph sheet after driving a densitometer across the spot. Some aspects of the behavior of the STTA chelates on the thin-layer of silica gel have also been discussed.
Photoinduced Reactions. LXVIII. Photochemical Dehydrogenation of Imidazolines to Imidazoles
Authors: Matsuura Teruo , Ito Yoshikatsu , Saito Isao
Published: July 2006

Imidazolines were found to be dehydrogenated to imidazoles by irradiation at 2537 Å or above 2900 Å in acetone. The n,π* triplet acetone acts as a hydrogen-abstracting agent giving 4- and/or 5-imidazolinyl radicals which in turn are transformed into imidazoles. This scheme is supported by the fact that the AIBN-initiated dehydrogenation of imidazolines gave corresponding imidazoles, that oxygen quenched the photochemical dehydrogenation, and that in some cases coupling products between the imidazolinyl and the acetone ketyl radicals were formed. Various data indicate that the imidazolinyl radical reverts to the parent imidazoline by hydrogen transfer from the acetone ketyl radical during the course of photolysis.
Molecular Structure of N-Methylacetamide as Studied by Gas Electron Diffraction
Authors: Kitano Mitsuo , Fukuyama Tsutomu , Kuchitsu Kozo
Published: July 2006

The bond distances (rg) and angles (rα) in N-methylacetamide have been determined by gas electron diffraction as follows: C–C=1.520±0.005 Å, N–C (methyl)=1.469±0.006 Å, N–C (carbonyl)=1.386±0.004 Å C=O=1.225±0.003 Å, C–H (average)=1.107±0.005 Å, ∠N–C=O=121.8±0.4°, ∠C–N–C=119.7±O.8°, ∠C–C–N=114.1±1.5°, ∠H–C–H(average)=110.4±2° and ∠H–N–C(carbonyl)=110±5°. In comparison with the molecular structure in the crystal, the N–C(carbonyl) bond is about 0.10 Å longer, whereas the C–C and C=O bonds are about 0.02 and 0.01 Å shorter, respectively. The two methyl groups are in the trans conformation about the N–C (carbonyl) bond, no other conformer being observed.
The Electrochemical Fluorination of Dithiols and Cyclic Sulfides
Authors: Abe Takashi , Nagase Shunji , Baba Hajime
Published: July 2006

The electrochemical fluorination of dithiols [1,4-butanedithiol (I), 1,5-pentanedithiol (II), and 3-oxapentane-1,5-dithiol (III)] and cyclic sulfides [tetrahydrothiophene (IV), 2-methyltetrahydrothiophene (V), 3-methylthiophene (VI) and tetrahydrothiopyran (VII)] was conducted. Dithiols afforded the corresponding fullyfluorinated analogs of the starting dithiol (SF5(CF2)n SF5; n=4 from 1,5 from II; SF5CF2CF2OCF2CF2SF5 from III) and the cyclic products (perfluorotetramethylenesulfur tetrafluoride from I, perfluoro-2-methyltetramethylenesulfur tetrafluoride, perfluoro-3-methyltetramethylenesulfur tetrafluoride, and perfluoropentamethylenesulfur tetrafluoride from II, and perfluoro-4-oxapentamethylenesulfur tetrafluoride from III). The corresponding perfluoro-cyclic sulfur(VI) compounds were obtained from IV, V, VI, and VII in reasonable yields. The novel perfluoropolymethylene bis(sulfur pentafluoride)s are transparent heavy liquids. Their physical properties and 19F NMR and IR data are reported.
The Calculation of the π-Electron Orbital Energies of the Allyl Cation, Butadiene, and Cyclic Polyenes by Means of Green’s Function Method
Authors: Shimada Katsumi , Okido Sadao , Tanimoto Osamu
Published: July 2006

Green’s function matrix method for the calculation of the orbital energies of π-electron systems, which has been discussed in previous papers, is applied to the allyl cation, butadiene, rectangular cyclobutadiene, and cyclic polyenes with various molecular lengths. The higher-order correction for the Hartree-Fock orbital energies are calculated, and in the case of butadiene the theoretical value of the ionization potential is discussed in comparison with the experimental data. The relation between the higher-order correction effect and the molecular length is illustrated in the cases of the cyclic polyenes. In particular, the breakdown of perturbation calculation based on the Hartree-Fock orbitals occurs in the case of the C30H30 molecule.
Kinetics of the Aquation of Iron(III) Monophenolate Complexes; Absence of the Acid-dependent Path
Authors: Nakamura Koichi , Tsuchida Toshihiko , Yamagishi Akihiko , Fujimoto Masatoshi
Published: July 2006

The complex formation between Fe(III) and 10 kinds of phenols was investigated using a stopped-flow apparatus. It was confirmed that the reaction rate is acid-independent in the acid region 0.01–1.0 m. A mechanism for the aquation of the iron (III)-phenol complex is proposed in which a proton transfers intramolecularly from a co-ordinated water molecule to a phenolate ion, viz., Fe(OH2)5A2+→Fe(OH2)4(OH)·AH2+. From the observed isotope effects it was concluded that the state of a proton of HA in Fe(OH2)4(OH)·AH2+ differs from that in a free phenol.
NMR Study of Amino Acids and Their Derivatives. V. Structures and Formation Constants of Zinc-l-Aspartic Acid Complexes in Aqueous Solution
Authors: Ishizuka Hidehiro , Yamamoto Takeo , Arata Yoji , Fujiwara Shizuo
Published: July 2006

NMR spectra of l-aspartic acid coordinated with Zn ions were measured in aqueous solution at various pH values. Three species of zinc-l-aspartic acid complexes were identified i.e., 1 : 1 zinc–l-aspartic acid(zwitter ionic form) complex (MAH), and 1 : 1 and 1 : 2 zinc–aspartic acid(anionic form) complexes (designated as MA and MA2, respectively). It is shown that, in MAH, the amino acid coordinates with Zn as a monodentate ligand, whereas in MA and MA2, approximately 65% of the molecules of amino acid coordinate as a tridentate ligand. From the chemical shift data, the equilibrium constants for these complexes are determined as follows: pKa-(MAH)=5.3±0.2 and logK2=4.5±0.2 where Ka(MAH)=[MA][H+]/[MAH] and K2=[MA2]/[MA][A].
Heat Capacity of Tetramethylsilane in the Region from 2 to 26 K and Premelting Range
Authors: Shinoda Takako , Enokido Hisae , Maeda Yoji , Tomita Hiroshi , Mashiko Yo-ichiro
Published: July 2006

The heat capacity of tetramethylsilane was measured at temperatures from 2 to 26 K and in the premelting temperature range for two crystalline forms. There are two crystalline forms in solid tetramethylsilane. The heat of fusion and triple point temperature of a stable form were found to be 1611.2±0.9 cal/mol and 174.049 K, while those of a metastable form to be 1396.0±0.8 cal/mol and 170.981 K. Tetramethylsilane was highly purified by preparative gas chromatography. The amount of impurity in the specimen of Si(CH3)4 was estimated to be 0.0046 mol% from measurement of the melting point range for two crystalline forms. The Debye characteristic temperature at 0 K, θD(0), was derived from low temperature heat capacity data, and the θD(T)⁄θD(0) curve was compared with those for C(CH3)4 and CF4. Despite high purity, Cp values for two crystalline forms in the region below melting points increases abnormally with the rise of temperature. The phenomena were interpreted as due to effects of formation of vacancies in the crystals and of melting accompanied by molecular orientation transition; analysis of heat capacity curves for the two crystalline forms was made in the region befow the melting point.
Asymmetric Hydrogenation of C=O Double Bond with Modified Raney Nickel Catalyst. XXV. Contributions of pH-Adjusting Reagents in the Asymmetric Hydrogenation
Authors: Tanabe Tadashi , Okuda Kazuo , Izumi Yoshiharu
Published: July 2006

In the asymmetric hydrogenation of methyl acetoacetate with modified Raney nickel catalysts, the effects of pH-adjusting reagents were studied using ds-tartaric acid, ls-2-hydroxyisovaleric acid, l-glutamic acid, and l-aspartic acid as the modifying reagents. The effects of various metal ions and ammonium ions were investigated at pH 5.0. The asymmetric activity of the catalyst modified with the 2-hydroxy monocarboxylic acid or 2-amino dicarboxylic acid was not affected by the pH-adjusting reagents. However, 2-hydroxy dicarboxylic acid was markedly influenced by the reagents. The univalent metal ion was more effective than divalent or ammonium ions. Sodium hydroxide was the best pH-adjusting reagent. The adsorption state of the modifying reagent was discussed on the basis of the effects of the pH-adjusting reagent.
Chemistry of Cyanoacetylenes. Part XIV. One-step Synthesis of Some Ethynyl Heterocycles and Their Reactions with Diazomethane
Authors: Sasaki Tadashi , Eguchi Shoji , Sugimoto Michio
Published: July 2006

The Ritter reaction of cyano- and chlorocyanoacetylene with appropriate substrates provided a facile one step synthesis of 4,4-dimethyl-2-ethynyloxazoline (5), 4,4,6-trimethyl-2-ethynyl (7) and -2-chloroethynyl-5,6-dihydro-1,3-oxazine (8), 5,5-dimethyl-3-isopropylidene-2-ethynyl- (10) and -2-chloroethynyl-1-pyrroline (11). On treatment with diazomethane, 7 gave 4,4,6-trimethyl-2-(4-1H-pyrazolyl)- (13) and -2-(3-1H-pyrazolyl)-5,6-dihydro-1,3-oxazine (14) in 42 and 40% yields respectively, while 8 afforded only 4,4,6-trimethyl-2-[3-(4-chloro-1-methyl)-pyrazolyl]-5,6-dihydro-1,3-oxazine (15) in 52% yield. On the other hand, 10 gave 5,5-dimethyl-3-isopropylidene-2-(3-1H-pyrazolyl)-1-pyrroline (16) in 64% yield and 11, 5,5-dimethyl-3-isopropylidene-2-[3-(4-chloro-1-methyl)-pyrazolyl]-1-pyrroline (17) in 16% yield.
Synthetic Studies by the Use of Carbonates, II. An Easy Method of Preparing Cyclic Carbonates of Polyhydroxy Compounds by Transesterification with Ethylene Carbonate
Authors: Komura Hajime , Yoshino Teruo , Ishido Yoshiharu
Published: July 2006

Transesterification reactions of polyhydroxy compounds, such as 1-O-p-nitrobenzoyl-, 1-O-benzylglycerols, 1,2;3,4-di-O-, 3,4-O-isopropylidene-d-mannitols, 1,2-O-isopropylidene-α-d-glucofuranose, uridine, 1,2;5,6-di-O-isopropylidene-d-mannitol, and d-mannitol, by ethylene carbonate were attempted; the corresponding products were obtained in good yields except in the case of uridine, which gave 2,2′-anhydro-1-β-d-arabinofuranosyluracil.
Structural Effects on the Properties of Nonionic Surfactants. II. Acetal Type Homogeneous Nonionics Having Polyoxyethylene Chains Terminated with Methoxyl Group
Authors: Takahashi Hideo , Kuwamura Tsunehiko
Published: July 2006

A series of homogeneous acetal nonionics (AGM types) with the general formula RCH[O(C2H4O)mCH3]2 were prepared from higher alkanals (C8–C14) and several pure polyoxyethylene (POE) glycol monomethylethers (m: 3–6), and purified by repeated distillation in vacuo. Cloud point, critical micelle concentration (CMC) and molecular area on adsorbed film were determined for AGM types. The results were compared with data on homogeneous acetals (AG types) having terminal hydroxyl in POE chains. The result confirms the suggestion that two POE chains in AG strongly interact with each other owing to intramolecular hydrogen-bonding and intertwisting. AGM are extremely low foaming nonionics although their ability to lower surface tension is comparable to that of the usual nonionics.
The Cation-radical Salts Derived from Benzo- and Dibenzo-phenothiazines
Authors: Matsunaga Yoshio , Suzuki Yukio
Published: July 2006

The chloride, iodide, and perchlorate of benzo- and dibenzo-phenothiazine cation-radicals have been prepared by the reaction of an equimolar mixture of the thiazine and its S-oxide with an appropriate acid. The vibrational spectra of the products have been found to be in close agreement with those of the bromides made by the familiar oxidation of thiazines with bromine. The results of electronic spectral and ESR measurements have furnished further support for our conclusion that the thiazine cation-radical salts can be prepared by the above-mentioned reaction. The electronic spectra of the iodides of benzophenothiazines have been found to differ markedly from those of other salts and to bear a resemblance to those of the low-resistivity iodine complexes.
Thermodynamic Properties of Some Isomeric Butyl Alcohol Mixtures
Authors: Murakami Sachio , Benson G C
Published: July 2006

Molar excess enthalpies and molar excess volumes are reported for binary mixtures of n-butyl alcohol with isobutyl alcohol, sec-butyl alcohol, and t-butyl alcohol. All of the measurements were carried out at 25°C except for the excess enthalpies of n-butyl alcohol–t-butyl alcohol which were determined at 26°C. Interpretation of the results in terms of a lattice model was investigated.
The Coupled Perturbed Hartree-Fock Calculations of the Magnetic Susceptibility for Some Nonbenzenoid Aromatic Hydrocarbons
Authors: Mikami Yasushi , Miyai Seiko , Nakajima Takeshi
Published: July 2006

The semi-empirical SCF MO method is applied to the calcutations of the magnetic susceptibility of the π-electron systems of several nonbenzenoid aromatic hydrocarbons. To avoid origin-dependent results, a method actually equivalent to Hall and Hardisson’s one which is currently called the coupled perturbed Hartree-Fock method is used. With the best-fit parameters, the calculated results are in good agreement with the available experimental values except for the case of aceheptylene.
Liquid-phase Oxidation Catalyzed by Cu(II)–Cl System, I. Oxidation of Cyclohexene
Authors: Imamura Sei-Ichiro , Banba Toshiaki , Takegami Yoshinobu
Published: July 2006

Oxidation of cyclohexene catalyzed by Cu(II)–Cl systems was carried out in glacial acetic acid. The oxidation of cyclohexene with cupric chloride was highly accelerated by addition of various alkali chlorides. The decomposition of cyclohexenyl hydroperoxide, an intermediate product of the oxidation, was also accelerated by this catalyst system. Salts other than alkali chlorides had little effect. It was concluded that the activation of copper catalyst was due to the chloride ions which form a complex with copper. In the course of the reaction the catalyst loses its activity through ligand exchange with solvent molecule, acetic acid.
An Electron Spin Resonance Study of the Steroid Conformation –6-Oxohelvolic Acid (Triketone)–
Authors: Fujisawa Takiko , Okuda Shigenobu , Fujita Yuzaburo
Published: July 2006

The triketone (6-oxohelvolic acid (IIa) or its tetrahydro-derivative (IIb)) was readily oxidized in air into the anhydride (IIIa or b) in an alkaline solution; it spontaneously turned red or deep green and then gradually lost its color. In this reaction process, the presence of a relatively stable intermediate radical was confirmed by the ESR measurement. As a result of an analysis of the well-resolved proton hyperfine structure of this radical, it was explained that the structure of helvolic acid is of the protostane type: that is, it is a distinctive structure of the trans-fusion of the A/B ring juncture and a boat form of the B-ring. A reasonable oxidation mechanism including this intermediate radical was presented.
A Novel Degradation Pathway of l-Ascorbic Acid under Non-oxidative Conditions
Authors: Goshima Kazuaki , Maezono Norihide , Tokuyama Kanji
Published: July 2006

The degradation of l-ascorbic acid (1) in methanol was studied in the presence of boron trifluoride-etherate under non-oxidative conditions. Two epimeric compounds containing an acetal group (7a and 7b) were isolated as the intermediates and 2-methoxalylfuran (13) the final product. From the result, the degradation pathway of 1 in methanol was proposed to be 1→7→13. By analogy with the proposed pathway, one in an aqueous acid was also presented.
Autoxidation of Aromatic Hydrocarbons Catalyzed with Cobaltic Acetate in Acetic Acid Solution. II. Oxidation of Ethylbenzene and Cumene
Authors: Kamiya Yoshio , Kashima Mikito
Published: July 2006

The oxidation of ethylbenzene and cumene catalyzed with cobaltic acetate in acetic acid was studied kinetically in order to elucidate the reaction mechanism and the roles of cobaltic salt. The maximum absorption rate of oxygen as well as the maximum reduction rate of Co(III) in the oxidation of ethylbenzene or cumene were of first order with respect to the initial concentration of hydrocarbon, of inverse first order with respect to the initial concentration of Co(II), and of second order with respect to the initial concentration of Co(III). The kinetic equations are therefore just the same as in the case of toluene, but d[Co(III)]/d[O2] gave a quite different average value of 3.8, showing that almost no regeneration of Co(III) from Co(II) due to oxidation with peroxidic compounds occurred. Both rates were remarkably accelerated by the addition of sodium acetate and also influenced by a small amount of water. The order of oxygen absorption rate in oxidation was toluene>ethylbenzene>cumene in contrast to the order of hydrogen abstraction rate by peroxy radicals. The apparent activation energy for these hydrocarbons was found to be 10.1 kcal mol−1.
Phase Transition in the Ionic Modification of Phosphorus Pentachloride, [PCl4][PCl6]. Chlorine Nuclear Quadrupole Resonance Study
Authors: Chihara Hideaki , Nakamura Nobuo
Published: July 2006

Chlorine-35 nuclear quadrupole resonance frequencies in the ionic crystal PCl4+·PCl6− were redetermined. Ten resonance lines were found and their temperature dependences were measured below the second order phase transition point at 102 K. The splitting Δvi in the resonance lines in the low temperature phase showed a similar temperature dependence as the order parameter. This was accounted for by a librational soft mode theory based on an anharmonic coupling between molecular or ionic librational modes in the crystal.
Synthesis of Pyrazole Derivatives Using 1-Benzoyl-1-phenylhydrazine
Authors: El-Sayed Abdou Ahmed , Ohta Masaki
Published: July 2006

Condensation of 1-benzoyl-1-phenylhydrazine (I) with β-ketoesters and β-diketones was investigated. Reaction of I with ethyl acetoacetate, ethyl benzoylacetate and diethyl acetonedicarboxylate in the presence of phosphorus pentoxide afforded the corresponding hydrazones which were easily cyclized by sodium hydroxide to give pyrazole derivatives. Reaction of I with acetylacetone proceeded to give hydrazone without condensing agent. 4-Carboxy-1,5-diphenylpyrazol-3-ylacetic acid and its mono- and diester were also prepared.
Heat Capacity of Solid Phosphorus Pentachloride between 4 and 150 K. Nature of the Transition at 102 K.
Authors: Chihara Hideaki , Nakamura Minoru , Masukane Kazuyuki
Published: July 2006

Molar heat capacity of solid P2Cl10 was measured between 4 and 150 K with an adiabatic calorimeter, with particular attention to the phase transition at 102.0±0.2 K. The heat and entropy of the transition were 148±3 Jmol−1 and 1.67±0.03 JK−1mol−1. Shape and magnitude of the anomalous heat capacity depend on the method of preparation. Anomaly in the heat capacity begins at about 75 K, rises gradually to a maximum of 9.12±0.08 JK−1mol−1 at 102.0 K and tails off at about 110 K. The shape of the excess heat capacity curve can be explained satisfactorily by the librational soft-mode theory which assumes that PCl6 anions tend to change equilibrium orientation with temperature.
Studies of Peptide Antibiotics. XXVIII. Syntheses of Sesquigramicidin S and Digramicidin S
Authors: Matsuura Shuji , Waki Michinori , Kato Tetsuo , Izumiya Nobuo
Published: July 2006

Two macro-ring analogs of gramicidin S, namely cyclo(–l-Val–l-Orn–l-Leu–d-Phe–l-Pro–)3 (sesquigramicidin S) and cyclo(–l-Val–l-Orn–l-Leu–d-Phe–l-Pro–)4 (digramicidin S), were prepared to investigate the influence of the ring size of gramicidin S for antibacterial activity. Several linear analogs such as H–(l-Val–l-Orn–l-Leu–d-Phe–l-Pro)n–OH (n=2, 3 and 4) were also prepared as reference compounds. All these macroring and linear analogs showed weaker activity than gramicidin S and synergistic property when each of the analogs is mixed with gramicidin S. Measurements of optical rotatory dispersion were made with these analogs and gramicidin S in solvents of ethanol and 8 M aqueous urea. From these experiments, it was suggested that the mode of antibacterial action of the macro-ring analogs and their conformations are similar to those of the linear analogs.
Synthetic Studies of Amino Acids by the Use of Copper(II) Complex. III. Syntheses of Several 2-Amino-2-deoxyaldonic Acids by the Use of Bisglycinato- and N-Pyruvylideneglycinatoaquocopper(II)
Authors: Ohdan Shohji , Okamoto Toshiro , Maeda Sadao , Ichikawa Tetsuya , Araki Younosuke , Ishido Yoshiharu
Published: July 2006

A comparative study of the relative reactivity of bisglycinatocopper(II) and N-pyruvylideneglycinatoaquocopper(II) in a base-catalyzed condensation reaction with aldehydo sugar derivatives concluded that the latter complex is much more reactive than the former. This reaction was found to proceed with a considerably high stereoselectivity to afford blocked 2-amino-2-deoxyaldonic acids with a threo configurational relationship between C–2 and C–3, and between C–3 and C–4. The resultant products were converted to the corresponding free 2-amino-2-deoxyaldonic acids in good yields by deblocking them with Amberlite IR-12OB(H form).
Single Crystal Electron Spin Resonance Spectra of Magnetically Dilute Copper(II) Ion in Some Five-coordinate Adducts of Zinc(II) β-Diketonate Complexes
Authors: Misumi Seizo , Isobe Toshiyuki , Sugiyama Kuniyoshi
Published: July 2006

The single crystal ESR spectra of some five-coordinate adducts of copper(II)-doped zinc(II) β-diketonate complexes [Cu/Zn(acac)2H2O], [Cu/Zn(acac)2γ-pic], [Cu/Zn(bzac)2MeOH], and [Cu/Zn(bzac)2py] (acac=acetylacetone anion, bzac=benzoylacetone anion, py=pyridine, γ-pic=γ-picoline, MeOH=methanol) were measured at room temperature. The principal values of the g tensor and A tensor of 63Cu were calculated. The single crystal g-values of all the adducts suggested a dx2−y2 ground state for the approximately square-based pyramidal structure, and were found to be consistent with crystallographic data. In the single crystals of [Cu/Zn(acac)2H2O] and [Cu/Zn(bzac)2py], two magnetic centers were determined, this being the first time for them to have been found by ESR study.
Charge-transfer and Proton-transfer in the Formation of Molecular Complexes. VIII. Benzidine–2,4-Dinitrophenol Complexes
Authors: Saito Gunzi , Matsunaga Yoshio
Published: July 2006

The simultaneous operation of charge-transfer and proton-transfer interactions was demonstrated in the orange complex and also in the brown complex of a 3 : 2 composition. The former one quickly becomes the yellow monohydrate of the 1 : 1 salt upon exposure to air.
Dielectric Relaxation and Molecular Structure. XII. Dipole Moments and Dielectric Relaxation Times of Rigid Molecules in Solutions
Authors: Nagai Tohru , Koga Yoshinori , Takahashi Hiroaki , Higasi Keniti
Published: July 2006

Dielectric constants and losses of anthrone, xanthone, fluorenone and ten other rigid and almost rigid organic molecules were measured at the frequency of about 100 GHz in benzene at 25 °C. The dielectric relaxation times τ(1) and τ(2) and the dipole moments μ of these molecules were obtained and discussed.
Spectral Difference of the A and B Forms of Deoxyribonucleic Acid
Authors: Nishimura Yoshifumi , Morikawa Kosuke , Tsuboi Masamichi
Published: July 2006

Infrared absorption spectrum of an oriented film of deoxyribonucleic acid from Micrococcus lysodeikticus has been examined in its A and B forms. In the A form a weak band was observed at 807 cm−1, while in the B form this is absent and a broad and weak band appears at 832 cm−1.