bluuebunny/crossref_metadata_2025 huggingface dataset:
Pressure and Temperature Effects on Octahedral–Tetrahedral Equilibria in 3-Methylpyridine Solutions of Some Cobalt(II) Halides
Authors: Kojima Kazuo
Published: July 2006

The visible absorption spectra of CoX2 (X=Cl, Br) in 3-methylpyridine (3-Me-py) solutions have been measured in the pressure range of 1 bar—3 kbar at room temperature, and in the temperature range of ≈5–≈76 °C at 1 bar. The equilibrium, [CoX2(3-Me-py)2] (tetrahedral)+2(3-Me-py)\ightleftharpoons[CoX2(3-Me-py)4] (octahedral), is found to be followed over this pressure range. Higher pressures favor the octahedral species with the volume changes −18–−19 cm3 mol−1 at 1 bar. On the other hand, the above equilibrium holds fairly well at temperatures up to about 40 °C. Higher temperatures favor the tetrahedral species, the heats of reaction, being 56.7 kJ mol−1 (5.0–44.8 °C) and 58.6 kJ mol−1 (4.8–34.2 °C) for the chloro and bromo complexes, respectively. An intense and broad band appears around 400 nm at elevated temperatures especially for the bromo complex solution. This band may be assigned to a charge-transfer band occurring in a contact ion pair of solvent molecule 3-Me-py with X− arising from the dissociation of the tetrahedral species [CoX2(3-Me-py)2].
Carbon-13 NMR and IR Spectroscopic Studies on Some 7-Oxabicyclo[2.2.1]heptanes and -heptenes. n–π Interaction and Hydrogen Bonding
Authors: Senda Yasuhisa , Ohno Akihiko , Ishiyama Jun-ichi , Imaizumi Shin , Kamiyama Shin-ichi
Published: July 2006

The 13C NMR spectra of diastereomeric pairs of the title compounds together with some tetrahydrofurans were examined and the chemical shifts were compared with those for the corresponding bicyclo[2.2.1]heptanes and -heptenes. The intramolecular interaction between the n-orbital of an oxygen atom and the π-orbital of an olefinic bond was found in 2-methylene-7-oxabicyclo[2.2.1]heptane. Intramolecular hydrogen bonding between the 7-oxygen and the hydroxyl group occurs in exo-7-oxabicyclo[2.2.1]heptane-2-methanol.
Functionalization of 2-Deoxy-2,3-dehydro-N-acetylneuraminic Acid Methyl Ester
Authors: Okamoto Kaoru , Kondo Tadao , Goto Toshio
Published: July 2006

The acetyl protected 2-deoxy-2,3-dehydroneuraminic acid methyl ester was functionalized by modifying its 2,3-double bond to convert it into new glycosyl donors such as 2,3-dibromo-, 2,3-epoxy-, and 2-halo-3-hydroxyneuraminic acid derivatives.
A Synthesis of Optically Active 4-Diethoxyphosphinyl-3-(1-hydroxyethyl)-2-azetidinone: A Potential Precursor to (1-Aminoalkyl)phosphonic Acid Derivatives
Authors: Shiozaki Masao , Masuko Hidekazu
Published: July 2006

Optically active 4-diethoxyphosphinyl-3-(1-hydroxyethyl)-2-azetidinone (8) was synthesized from (2R,3R) N-diethoxyphosphinylmethyl-2,3-epoxybutyramide derivatives, and compound 8 was alternatively synthesized from (3R,4R)-4-acetoxy-3-[(R)-1-(t-butyldimethylsilyloxy)ethyl]-2-azetidinone via 3-[1-(t-butyldimethylsilyloxy)ethyl] derivative.
Reactivities of Stable Rotamers. XIX. Basicities of Rotameric 9-[2-(Dialkylaminomethyl)-6-methylphenyl]fluorenes and Solvent Effects on Them
Authors: Nakamura Mikio , Oki Michinori
Published: July 2006

The pKa′ values of the trifluoroacetate salts of the title compounds were determined in THF–water (3:2) solution at 25 °C by potentiometric titration: in every compound examined, basicity of the ap rotamer was higher than that of the sp rotamer. Differences in pKa′ values (ΔpKa) between the rotamers are in the range of 0.55 to 1.14 pKa units, depending upon the substituents on the nitrogen atom. The ΔpKa values in chloroform-d solution at 80.1 °C determined by taking advantage of the equilibrium constants of the salts and the free amines were larger than those obtained in aqueous THF solutions and were nearly independent of the substituents. The results were explained in terms of the intramolecular NH-π interactions in the ap salts, which are not possible in the sp. 1H and 13C NMR spectral data were in conformity with the presence of the interactions. Examination of the population ratios in various solvents revealed that sp conformers of the free amines are generally favored over the ap in polar, proton-accepting solvents, but the reverse is true for the trifluoroacetate salts. As the results, ΔpKa values are large in toluene and chloroform but are rather small in tetrahydrofuran, acetonitrile, and nitromethane. Possible causes for the differences including solvation and hydrogen bond formation are discussed.
Synthesis of 2,6-Dimethyl-6-(8-methyl-4-methylene-7-nonenyl)-2-cyclohexene-1-methanols from α-Santonin
Authors: Nagano Hajime , Masunaga Yukari , Matsuo Yukiko , Shiota Michio
Published: July 2006

α-Santonin was converted to 2,6-dimethyl-6-(8-methyl-4-methylene-7-nonenyl)-2-cyclohexene-1-methanols (1a and 1b). Both spectral data of 1a and 1b were found to be different from those reported for magydar-2,10(20),13-trien-17-ol, a diterpene isolated from Magydaris panacifolia (Vahl) Lange. This indicates that the structure of the natural diterpene should be revised; the structure was later revised to t-6-hydroxymethyl-1, t-3-dimethyl-t-2-(3-methyl-2-butenyl)-3-(4-methyl-3-pentenyl)-r-1-cyclohexanol.
27Al High-Resolusion Solid-State NMR Study of Hydration of Ultrafine Powder of Aluminum Nitride
Authors: Hayashi Shigenobu , Hayamizu Kikuko , Yamamoto Osamu
Published: July 2006

27Al NMR spectra of hydrated aluminum nitride ultafine powder, measured using magic angle sample spinning technique, showed two peaks which can be attributed to Al coordinated by four N atoms and to Al coordinated by six O atoms, and the hydration process was discussed.
Double Inclusion of Methylated Cyclodextrin and Sodium Benzenesulfonate by Na–, Ca–, and Cu–Montmorillonites
Authors: Kijima Tsuyoshi
Published: July 2006

The uptake of methylated α- and β-cyclodextrins by Na–, Ca–, and Cu–montmorillonites at 25 °C in the presence of sodium benzenesulfonate has been studied. X-Ray diffraction data revealed that the cyclodextrin molecules that embrace benzenesulfonate anion are intercalated as monolayer in the interlayer space of the clay minerals.
Microscopic and Dielectric Studies of CH3NH3I Crystal
Authors: Yamamuro Osamu , Oguni Masaharu , Suga Hiroshi
Published: July 2006

Observation of CH3NH3I crystal under a polarizing microscope showed a rectangular domain structure in the δ phase. Dielectric measurement revealed an antiferroelectric behavior of the same phase. These results indicate that the δ phase has orthorhombic or monoclinic structure with C–N axes of CH3NH3+ ions inclining along its a or b axis in an antiferroelectric way.
The Steam Stability of H-ZSM-5-Type Zeolites Containing Alkaline Earth Metals
Authors: Fujisawa Kazuyoshi , Sano Tsuneji , Suzuki Kunio , Okado Hideo , Kawamura Kichinari , Kohtoku Yasuhiko , Shin Shigemitsu , Hagiwara Hiroyuki , Takaya Haruo
Published: July 2006

The steam stability of H-ZSM-5-type zeolites containing alkaline earth metals was investigated by means of 27Al MASNMR, the TPD of NH3, and methanol conversion reactions. It was found that the steam stability of the H-ZSM-5-type zeolites is greatly improved by adding alkaline earth metals.
Conversion of β-Senepoxide to Crotepoxide: Total Synthesis of (+)-Crotepoxide
Authors: Ogawa Seiichiro , Takagaki Tohei
Published: July 2006

Total synthesis of (+)-crotepoxide has been accomplished by chemical conversion of (+)-β-senepoxide which was prepared from (−)-7-endo-oxabicyclo[2.2.1]hept-5-ene-2-carboxylic acid.
Synthesis and Biological Activity of Substance P Analogs Containing Pyrohomoglutamic Acid and Homoglutamine
Authors: Hashimoto Tadashi , Sakura Naoki , Hirose Kyoko , Uchida Yoshiki , Nishijima Miwako , Moro Tadashi
Published: July 2006

Eight substance P analogs substituted by l- or d-pyrohomoglutamic acid (6-oxo-2-piperidinecarboxylic acid) and l or d-homoglutamine at the position 5 and 6 were prepared by the solid phase method. The contractile activities of the analogs were compared with that of SP on isolated guinea-pig organs.
The Pulse-Photoconductivity of Poly(1-vinylpyrene)
Authors: Itaya Akira , Okamoto Ken-ichi
Published: July 2006

The migration of electronic excitation energy, the steady-state photoconductivity, the hole-drift mobility and the carrier-photogeneration efficiency of holes in poly(1-vinylpyrene)(PVPy) films were investigated and compared with those in poly(N-vinylcarbazole)(PVCz) films. Although the concentration of the excimer-forming sites in PVPy films was about twenty times as large as that in PVCz films, the magnitude of the steady-state photoconductivity of PVPy was comparable to that of PVCz. The hole mobility in PVPy films was about one-half as large as that in PVCz films. The electric field and temperature dependence of the mobility fit Gill’s empirical equation. The carrier-photogeneration efficiency, Φ, of PVPy was larger than that of PVCz. The filed dependence of Φ of PVPy for all the excitation bands was in good agreement with the Onsager theory of geminate recombination. The high photoconductivity of PVPy could be explained on the basis of these results.
Asymmetric Synthesis of (2R,3S)-2,3-Epoxyoctanal, a Key Intermediate of 14,15-Leukotriene A4
Authors: Tsuboi Sadao , Furutani Hiroyuki , Takeda Akira
Published: July 2006

Asymmetric reduction of ethyl 3-chloro-2-oxooctanoate with baker’s yeast gave ethyl 3-chloro-2-hydroxyoctanoate (3) [(2S,3R)/(2S,3S), 4:1] in 67% yield with >99% e.e. Chlorohydrin (2S,3R)-3 was converted to the titled compound in 34% total yield with 80% e.e. via the reduction, dehydrochlorination, and oxidation, successively. (2R,3R)2,3-Epoxyoctanal was also prepared from (2S,3S)-3 in 33% total yield with 94% e.e.
Binding Behavior of Metal Cations and Hydrophobic Ions from a Mixed Solution
Authors: Furusawa Kunio , Iwamoto Miyako , Matsumura Hideo
Published: July 2006

Critical experimental data are presented on the competitive adsorption of metal cations with different ionic valences to phospholipid vesicles, and on the binding of hydrophobic ions from mixed solutions with multivalent metal cations produced under different conditions by means of the Inductively Coupled Argon Plasma. It is apparent that the preferential effect in binding between the metal cations depends not only on their ionic valences but also on the concentrations of each ion at which the corresponding binding is carried out; i.e., the binding strength of the metal cations on the membrane surface increases in the following order: K+<Mg2+<Ca2+<La3+<Th4+, and this order comes to be more pronounced in the high-concentration region of each component. Furthermore, it is realized that, in binding from mixed solutions of hydrophobic ions and multivalent metal cations (Ca2+ or Th4+), a synergistic interaction between these ions occurs; i.e., the binding of hydrophobic anions is promoted by the presence of metal cations, while the binding of hydrophobic cations is hindered by the metal cations.
Mössbauer Spectroscopic Studies of Trialkyl- and Triaryltin Complexes of Transition Metal Cyanides
Authors: Katada Motomi , Uchida Yoshio , Iwai Kumiko , Sano Hirotoshi , Sakai Hiroshi , Maeda Yutaka
Published: July 2006

The structural diagnosis and lattice dynamics of three complexes, {[R3Sn](μ-NC)[Au(μ-CN)]}x (R=Me, Bu(n-Bu), or Ph), {[R3Sn]2[(μ-NC)4Pt]}x (R=Me, Bu, or Ph), and {[R3Sn]3[(μ-NC)6Fe]}x (R=Bu or Ph) have been undertaken by means of 57Fe-, 119Sn-, and 197Au-Mössbauer spectroscopic techniques. The Mössbauer parameters for the complexes indicate that all the tin atoms are coordinated with three alkyl or aryl groups and two cyano groups having a trigonal–bipyramidal structure. The asymmetry of the quadrupole split-peak intensity observed in the 119Sn-Mössbauer spectra for the complexes was attributed to the anisotropic mean square vibrational amplitude with respect to a molecular symmetry axis. The temperature dependence of the recoil-free fraction of the 119Sn-Mössbauer atom shows that the mean-square vibrational amplitude of tin atoms in the complexes falls in the range of values found for a number of one-dimensional organotin polymers. In 57Fe-Mössbauer spectroscopy, the quadrupole splitting for {[Bu3Sn]3[(μ-NC)6Fe]}x rapidly decreases with an increase in the temperature, reflecting small separations among the three dε levels in energy. The very large 197Au-quadrupole splitting for {[R3Sn](μ-NC)[Au(μ-CN)]}x was explained by assuming strong σ-donating and π-accepting properties of the CN ligand.
Reactivity of Hypervalent Species: Reactions of Anionic Penta-Coordinated Silicon Complexes towards Nucleophiles
Authors: Boudin Alain , Cerveau Geneviève , Chuit Claude , Corriu Robert J P , Reye Catherine
Published: July 2006

The reactivity of anionic penta-coordinated silicon complexes [RSi(O2C6H4-o)2]−Na+  1 with nucleophilic reagents has been studied. 1 can be reduced to organosilanes RSiH3 by metallic hydrides. Reactions with an excess of Grignard or organolithium reagents (R′MgX or R′Li) gave tetraorganosilanes RSiR′3. When only two molar equivalents of Grignard reagents (R′MgX) or lithium reagents (R′Li) are added to complexs 1 functional silanes RR′2SiX can be prepared.
The 127I Nuclear Quadrupole Resonance of an Iodine Complex with 1,3-Dithiane, C4H8S2·2I2
Authors: Terao Hiromitsu , Sakai Hiroshi
Published: July 2006

The 127I nuclear quadrupole resonance spectrum of 1,3-dithiane–2I2 is reported. Two distinct S···I–I arrangements are present in the crystal. The charge on each iodine atom is obtained; the bonding in the complex is discussed in connection with analogous thioether–iodine complexes. The resonance lines for terminal iodine atoms indicate positive temperature coefficients.
Dynamic NMR as a Nondestructive Method for the Determination of Rates of Dissociation. XIII. Sulfur Inversion in 9,9-Dialkyl-10-mesitylthioxanthenium Salts
Authors: Oki Michinori , Yamada Yasuhisa
Published: July 2006

The sulfur-inversion in the title compound (alkyl=ethyl) was found to take place with the following activation parameters by dynamic NMR spectroscopy: ΔH\eweq=23.8±0.2 kcal mol−1, ΔS\eweq=2.6±0.4 cal mol−1 K−1. The significance of the near zero entropy of activation is discussed. The mesityl group in the title compounds also showed restricted rotation of which barrier to rotation was estimated to be 14 kcal mol−1 at 318 K for the compound where the alkyl is a methyl.
Metal(II) d-Tartrates Catalyzed Asymmetric Ring Opening of Oxiranes with Various Nucleophiles
Authors: Yamashita Hiroyuki
Published: July 2006

The asymmetric ring opening of meso-2,3-disubstituted oxiranes with thiols, aniline, and trimethylsilyl azide was studied by the use of metal(II) d-tartrates as heterogeneous chiral Lewis acid catalysts. The enantioselectivity varied widely with the combination of oxirane, nucleophile, and metal(II) d-tartrate, and Zn(II) d-tartrate gave the best enantioselectivity in the respective reactions of 1,2-epoxycyclohexane with 1-butanethiol, aniline, and trimethylsilyl azide to afford the corresponding adducts in 85, 58, and 42% ee, respectively. Furthermore, the kinetic resolution of racemic oxiranes with thiols catalyzed by Zn(II) d-tartrate was studied.
Chemistry of Germanium Atoms. II. Reactions of Thermally Evaporated Germanium Vapor with Organic Halides
Authors: Mochida Kunio , Tashiro Kumiko , Yoshida Yasuhiro , Mizuno Yasuhisa
Published: July 2006

Thermally generated germanium atoms were found to react with organic halides by insertion into carbon–halogen bonds. The resulting germylenes abstracted halogens from organic halides to form trihalogermyl derivatives. Tetrahalogermanes were also formed by the abstraction of halogens with germanium atoms.
Cathodic Addition of Benzylidyne Trichloride to Ketones and Aldehydes
Authors: Steiniger Michael , Schäfer Hans J
Published: July 2006

Ketones are converted to homologated enones 7a–g in good yields by cathodic addition of benzylidyne trichloride (1d). As intermediates α-chlorooxiranes 6 are assumed, which rearrange via α-keto carbenium ions 9 to enones. The intermediacy of 9 is supported by the addition of 1d to norcamphor, where the products indicate equilibrating norbornyl cations as intermediates. α,β-Unsaturated ketones lead depending on steric shielding of the double bond to the cyclopropane 23 as 1,4-adduct or the enone 26 as 1,2-adduct. With aldehydes and 1d, α-chloro or α-hydroxy ketones, the conversion products of 2-chlorooxiranes, are obtained.
Synthesis and Application of Some 1-[8-Hydroxy-5(or 7)-quinolinyl]alkylidene-Substituted Heterocycles as Bactericides, Funjicides, and Bioregulator
Authors: Khalil Zarif Haleem , Yanni Amal Sabet , Khalaf Ali Ali , Abdel-Hafez Ali Ali , Abdo Raafat Foaad
Published: July 2006

Interaction of 5-acetyl-8-quinolinol, corresponding 1-ethylquinolinium iodides, and 8-hydroxyquinoline-7-carbaldehyde with diethylmalonate under basic condition gave the corresponding of 4–6. Further reaction of 4–6 with hydrazine, phenyl hydrazine, hydroxylamine, urea, and/or thiourea gave the corresponding 1-[8-hydroxy-5(7)-quinolinyl]alkylidene-substituted heterocyclic derivatives (7–16) and corresponding 1-ethylquinolinium iodides (17–21). The structure of the synthesized compounds was confirmed by elemental and spectral analysis. The biological activity of 5-substituted 8-quinolinol was tested as microbicidal and bioregulator agents, the results obtained were interpreted according to their structure-activity relationships.
Behavior of the Enthalpy of Mixing in the Ternary Systems Lead–Antimony–Tin, Bismuth–Lead–Tin, and Bismuth–Cadmium–Tin at 950 K. I. Experimental Investigation
Authors: Badawi Walid Ahmad
Published: July 2006

Calorimetric studies on the enthalpies of mixing in the ternary systems Pb–Sb–Sn, Bi–Pb–Sn, and Bi–Cd–Sn have been carried out at 950 K. The partial enthalpy of mixing in the system Pb–Sb–Sn at quasi-binary section drawings goes through positive and negative regions. The partial enthalpy of mixing of lead is positive, while that of antimony is negative and takes a minimum between the quasi-binary section drawings xSn=0 and xSn⁄xPb=6⁄4. The partial molar enthalpy of mixing of bismuth in the ternary systems Bi–Cd–Sn and Bi–Pb–Sn shows level minima and the same behavior as observed for the partial enthalpy of mixing of antimony in the related system Pb–Sb–Sn. The partial enthalpy of mixing of tin in the system Bi–Pb–Sn is positive, while that of lead takes positive and negative values. Also the partial molar enthalpy of mixing of Cd in the system Bi–Cd–Sn shows a level minimum.
Synthesis and Epoxidation of Methyl trans-5,6-Diacetoxy-1,3-cyclohexadiene-1-carboxylate
Authors: Ogawa Seiichiro , Takagaki Tohei
Published: July 2006

The (±)-methyl 1,3-cyclohexadiene-1-carboxylate, a useful intermediate for synthesis of derivatives of shikimic acid, was prepared by bromination of (±)-methyl (1,3/2)-2,3-diacetoxy-4-cyclohexene-1-carboxylate, followed by debromination of the major dibromide obtained with zinc dust. Epoxidation of the diene with peracid gave selectively two 3,4-monoepoxides.
Thermodynamic Stability of Polycyclic Aromatic Hydrocarbons Detected in Our Environment
Authors: Aihara Jun-ichi
Published: July 2006

Various polycyclic aromatic hydrocarbons (PAHs) are distributed widely in our environment. Diesel particulate extract contains many larger PAHs. All these PAHs have a percent resonance energy larger than 2.50. Dibenzo[def,mno]chrysene and anthracene constitute the most unstable PAHs among them. A couple of reaction paths to the formation of ovalene are discernible in flames by inspecting the combustion products. It seems likely that a similar type of reactions take place in the envelopes of carbon stars to give large compact PAHs and graphite.
Mixed Surfactant Bilayers on Monodispersed Ferric Hydro Sols
Authors: Esumi Kunio , Sakamoto Yuichi , Yoshikawa Keiko , Meguro Kenjiro
Published: July 2006

The properties of mixed surfactant bilayers on monodispersed ferric hydro sol were studied by measuring the amount of surfactant adsorbed, particle size, and pyrene fluorescence spectra. The positively charged sols flocculated upon addition of sodium dodecyl sulfate (SDS) or lithium perfluoro-1-octanesulfonate (LiFOS) were redispersed by further addition of poly(oxyethylene) nonyl phenyl ether (NP7.5) due to the formation of a mixed surfactant bilayer on the sols. The mixed surfactant bilayer of SDS–NP7.5 on the sols was more easily formed than LiFOS–NP7.5. Fluorescence fine structure of pyrene gave information on the polarity of the microenvironment in the mixed surfactant layer on the sols.
Radical Cyclization in the Control of Regio- and Stereochemistry
Authors: Stork Gilbert
Published: July 2006

This article presents a review of the control of regio- and stereochemistry which is now possible by the use of the recently introduced haloacetal and the related halosilyl ether cyclizations, starting from a cyclohexenol or a cyclopentenol. The hydroxyl group is the control element which permits the addition of two carbon chains to the double bond of the allylic alcohol system, with complete regiospecificity and stereospecificity at the near end of the double bond, and with complete regiospecificity and high stereoselectivity at the far end of the bond. Examples of the use of the new methodology from the field of alkaloid, steroid and prostaglandin synthesis are given.
Transfer of Homologous Alkanols from Water to Fluorocarbon and Hydrocarbon Surfactant Micelles
Authors: Manabe Masahiro , Kawamura Hideo , Sugihara Gohsuke , Tanaka Mitsuru
Published: July 2006

The critical micelle concentration, cmc, of sodium perfluorooctanoate, SPFO, and sodium dodecyl sulfate, SDS, in the presence of two homologous series of alkanols (l-alkanols and ω-phenyl-l-alkanols) at very low concentrations of the alkanols Ca, was measured by a differential specific conductivity method. The free energy of transfer per CH2 group in the alkanols from water to the respective micelles, ΔG°(CH2), has been estimated from a linear relation of the rate of cmc-decrease, Δcmc/ΔCa, with the number of carbon atoms in the alkyl chain of alkanols. The respective values of ΔG°(CH2) obtained for two series of homologues added to a given surfactant are in good agreement with each other: ΔG°(CH2) is −1.73 kJ mol−1 in the SPFO system and −2.30 kJ mol−1 in the SDS system. The former has been found to be smaller in magnitude than the latter. On the basis of ΔG°(CH2), a thermodynamic parameter has been proposed which characterizes the degree of modification of a medium from its pure liquid state to surfactant micelles or to interfaces composed of a hydrocarbon or a fluorocarbon.
Liquid–Liquid Extraction of Some Class b Metal Ions with a Thiacrown Compound, 1,4,7,10,13,16-Hexathiacyclooctadecane
Authors: Sekido Eiichi , Kawahara Hideo , Tsuji Kaoru
Published: July 2006

The liquid–liquid extraction of various metal ions, especially of soft class b metal ions with a thiacrown compound, 1,4,7,10,13,16-hexathiacyclooctadecane (HTCO) using picrate ion (Pic−) was examined and compared with that of 1,4,8,11-tetrathiacyclotetradecane (TTCT). Although the extraction behavior of the class a, ab, and b metals with HTCO is fundamentally similar to that with TTCT, that of some metals belonging to class b metals with HTCO is different from that with TTCT. The extraction percentages of copper(II) and palladium(II) with HTCO are a few times larger than those with TTCT. Copper(I) and silver(I) are extracted with HTCO as the 1 : 1 complexes such as [Cu(htco)]+Pic− and [Ag(htco)]+Pic−, respectively, regardless of the relative concentration of the ligand to the metal. On the other hand, copper(I) and silver(I) complexes with TTCT are extracted with different compositions depending upon the relative concentration of the ligand to the metal.
t-Butylsulfinyl Phenylmethyl Carbanion. Conformation in Nonpolar Solvent
Authors: Ohno Atsuyoshi , Higaki Masato , Oka Shinzaburo
Published: July 2006

1H NMR spectra were studied for a carbanion derived from t-butyl phenylmethyl sulfoxide in tetrahydrofuran. It has been concluded that the conformation of the carbanion in solution is the same as that in a crystal. The carbanion exists in two diastereomeric dimeric forms in the presence of an equivalent amount of countercation, but it becomes a monomer when excess base exists in the solution.
Thermochemistry of Cobalt(III) β-Diketonates
Authors: Ribeiro da Silva Manuel A V , Ferrão Maria Luisa C C H
Published: July 2006

The standard molar enthalpies of formation of the crystalline complexes of cobalt(III) with 1-phenyl-1,3-butanedione (Hbzac), 2,2,6,6-tetramethyl-3,5-heptanedione(Hdpm), and 1,1,1-trifluoro-2,4-pentanedione (Htfac) were determined, at 298.15 K, by solution-reaction calorimetry:

ΔfH°m[Co(bzac)3,cr]=−877.1±8.7kJ·mol−1

ΔfH°m[Co(dmp)3,cr]=−1708±12kJ·mol−1

ΔfH°m[Co(tfac)3,cr]=−3191±15kJ·mol−1

The enthalpies of sublimation of Co(dpm)3 and Co(tfac)3, at 298.15 K, determined by high-temperature microcalorimetry were 126±3 and 114±2 kJ·mol−1, respectively. From the enthalpies of formation of the gaseous complexes, the average molar bond-dissociation enthalpies, 〈D〉(Co–O), were derived.
Hindered Rotation around Csp2–Csp3 Bonds in the Enol Forms of α-(9-Fluorenyl)-β-diketones and in 3,5-Disubstituted 4-(9-Fluorenyl)pyrazoles. An 1H NMR Study
Authors: Moreno-Mañas Marcial , Gonzalez Asensio , Marquet Jorge , Sanchez-Ferrando Francisco
Published: July 2006

Slow rotation around the Csp2–Csp3 bonds of the enol forms of 3-(9-fluorenyl)-2,4-pentanedione, 2-(9-fluorenyl)-1-phenyl-1,3-butanedione, and the corresponding bonds of the derived pyrazoles, was studied by variable temperature 1H NMR. For the pyrazoles, the values Tc=315–320 K (ΔGTc\eweq=15.1±0.1 kcal mol−1) and Tc=338±5 K (corresponding to ΔGTc(sp→ap)\eweq=18.1±0.2 kcal mol−1 and ΔGTc(ap→sp)\eweq=16.1±0.2 kcal mol−1) were found, respectively.
Optical Absorption by Mn2+ Ions in MnM(edta)·6H2O (M=Zn, Cu, Ni, and Co)
Authors: Togashi Hisashi , Kojima Norimichi , Ban Toshiro , Tsujikawa Ikuji
Published: July 2006

The optical absorption spectra of the Mn2+ ion in MnM(edta)·6H2O (M=Zn, Cu, Ni, and Co) were measured at low temperature. Fine structural bands corresponding to the 6A1g→4T2g (D) and 6A1g→4A1g, 4Eg (G) transitions were found. The fine structure corresponding to the 6A1g→4A1g, 4Eg (G) transition in the Zn compound were analyzed with the ligand field theory and the assignment of the absorption peaks was performed. Although the spectra of the Zn, Cu, and Co compounds are similar, those of the Ni compounds show significant broadening, which is possibly due to the energy transfer caused by the overlapping of the absorption bands of the Ni2+ and Mn2+ ions.
Long-Lived Triplet Radical Ion Pair State of Porphyrin-Methylviologen Combined Systems as Revealed by a Large Magnetic Field Effect on Its Lifetime
Authors: Saito Toshiro , Hirata Yoshinori , Sato Hisashi , Yoshida Toshikatsu , Mataga Noboru
Published: July 2006

The external magnetic field effect on the lifetime of the ion pair state has been examined for the porphyrinmethylviologen combined systems in polar solvents by using nanosecond laser flash photolysis techniques. Applying the external magnetic field, a drastic increase in the lifetime has been observed. For PllMV2+ in DMSO under the magnetic field of 50 mT, the ion pair lifetime was almost three times longer than the zero field value, which can be deemed the ideal case of the external magnetic field effect due to the hyperfine interaction mechanism. The results clearly showed that the long-lived ion pair was formed by the intramolecular electron transfer from the triplet state of porphyrin.
The Micellar Properties of Dodecyltrimethylammonium Chloride as Studied by Ion-Selective Electrodes and Fluorescence Probe Technique
Authors: Maeda Tamaki , Satake Iwao
Published: July 2006

The activities of the surfactant ion, counter ion, and co-ion in micellar solutions of dodecyltrimethylammonium chloride (DTAC) in the presence of NaCl were determined by using ion-selective electrodes. An application of the charged phase separation model gave an apparent degree of counter ion association to the micelle of 0.68 regardless of the salt concentration. A tentative estimation of the intermicellar concentrations of surfactant ion and counter ion was made on the basis of an assumption that the activity coefficients of the monomeric surfactant ion and co-ion were identical with each other. In the concentration range above the critical micelle concentration (cmc), the intermicellar concentration of the surfactant ion decreased gradually with increasing surfactant concentration, whereas the reverse was found for that of counter ion. Similar behaviors were also found for the activity coefficients of these ions. However, an increase in salt concentration caused a successive decrease in the concentration dependences of intermicellar concentrations as well as activity coefficients. Measurements were also made with the fluorescence decay curves of micelle-solubilized pyrene. An analysis based on the knowledge of the intermicellar concentration of surfactant ion estimated above revealed that the micelle aggregation number of DTAC remained virtually constant over wide concentration range above the cmc.
Photoacoustic Study of 280 nm Band of Acetone Vapor
Authors: Oka Takefumi , Kobayashi Humiyo , Oguma Naoki , Morohashi Makoto
Published: July 2006

Relaxation of the energy absorbed by acetone vapor (200 Torr) on excitation with UV (230–340 nm) was investigated by the photoacoustic technique. The presence of two relaxation paths was found by their difference in heat production rates: The faster path is S0→S1→T1→S0 and the slower path is S0→radicals→recombination products. The PA spectra corresponding to these paths were determined separately. The spectrum for the T1 path has a peak around 295 nm and extends to longer wavelengths beyond 310 nm. The spectrum for the decomposition path has a peak around 275 nm and overlaps with the spectrum for the T1 path in the region of λ<310 nm. The study of frequency dependences of PA signals showed the presence of faster and slower heat releasing steps in each path. In the T1 path, the faster and the slower steps are due to vibrational deactivation of hot T1 formed from S1 and of hot S0 formed from T1 respectively. In the radical path, the faster and slower steps are the deactivation of the hot radicals and the recombination of the thermalized radicals respectively. The addition of O2 to the system accelerated the heat release process via the relaxed T1 and also converted the slow heat release process of recombination into a fast process of addition reactions of O2 to the radicals.
Dichalcogen-Bridged Acenaphthenes as New Electron Donors
Authors: Aso Yoshio , Yui Koji , Miyoshi Takanori , Otsubo Tetsuo , Ogura Fumio , Tanaka Jiro
Published: July 2006

Three new electron donors, 5,6-dihydroacenaphtho[5,6-cd]-1,2-dithiole (1a), -diselenole (1b), and -ditellurole (1c) have been prepared with a view to developing new electron donors for low-dimensional molecular complexes. Their donor characters are markedly enhanced as compared with the corresponding dichalcogen-bridged naphthalenes. They formed charge-transfer complexes with tetracyanoquinodimethane (TCNQ). Their electrical conductivities increase in the order of polarizable chalcogen. The crystal structures of 1a–TCNQ complex and neutral 1c were determined by X-ray analyses. In the crystal, 1a and TCNQ form a unique mixed stack, that is, a pair of donors and a pair of acceptors make an alternately stacking column. Neutral 1c takes an almost planar conformation and molecules are connected to each other with strong Te–Te interactions.
Reinvestigation on Thermal Cycloaddition of 1-Aryl-2-(9-fluorenylidene)-1-haloethylenes
Authors: Minabe Masahiro , Yoshida Masaaki , Saito Seiji , Tobita Keisuke , Toda Takashi
Published: July 2006

The thermal treatment of 1-bromo-2-(9-fluorenylidene)-1-phenylethylene afforded three different types of [2+2]cycloaddition products. The 1-tolyl homolog showed similar trends, but the chloro analog gave only two types. These results suggest that reactions of the rigid and bulky allenes take place through a 2,2′-biradical giving head-to-head, head-to-tail, and tail-to-tail adducts through the expected processes.
Diastereomers of Methionine S-Oxide in the Hinge-Ligament Proteins of Molluscan Bivalve Species
Authors: Kikuchi Yasuo , Higashi Kiyoshi , Tamiya Nobuo
Published: July 2006

The diastereomer ratio was analyzed on methionine S-oxide residues formed by in vivo posttranslational oxidation of methionine residues in a protein. The hinge-ligament protein of molluscan bivalves is distinct from usual proteins in containing a large amount of methionine S-oxide. The methionine S-oxide was released from the protein by proteolytic digestions and was found to be a mixture of approximately equall amounts of two diastereomers, (5S)- and (5R)-l-methionine S-oxide.
Conductance of Electrolytes in Dipolar Aprotic Solvent Mixtures. II. Conductance of Lithium Perchlorate in Mixtures of Ethyl Methyl Ketone and Acetone with N,N-Dimethylformamide at 25 °C
Authors: Niazi M S K
Published: July 2006

The electrolytic conductance of LiClO4 has been determined in N,N-dimethylformamide (DMF) and its binary mixtures with acetone (Ac) and ethyl methyl ketone (MEK) at 25 °C. Ion association constants (KA) and limiting molar conductance (Λ0) were calculated from these data using Fuoss equation with modifications. The KA values of LiClO4 in these binary mixtures are interpreted in terms of solvent separated ion pairs while in pure Ac and MEK almost contact ion pairs are expected. A comparison is made for Λ0 and KA values of this salt in Ac and Ac–DMF mixtures with those obtained by Gill et al. Further, a comparison is made between these results and spectroscopically derived results by others in analogous media. LiClO4 has been found more associated in Ac–DMF solvent system than in the MEK–DMF mixed solvent system.
Electrophoresis of Progesterone Particles Dispersed in Aqueous Solutions of d-Glucose and Urea
Authors: Srivastava M L , Ram Bali
Published: July 2006

Electrophoretic mobilities of progesterone particles dispersed in aqueous solutions of d-glucose and urea, in the concentration range 10−3–104 mol l−1 have been measured to investigate electrical properties of the interface. Zeta potentials have been determined for this purpose. The dependence of zeta potentials on concentration has also been examined. Theory of the electrical double layer has been used to explain the results.
The Preparation and the Crystal Structure of 1,3,5,7-Tetramethyltetrahydro-1,3,5,7-tetrazocine-2,6(1H,3H)-dione
Authors: Ebisuno Toichi , Takimoto Michiaki , Takahashi Miyuki , Shiba Ryuichi
Published: July 2006

1,3,5,7-Tetramethyltetrahydro-1,3,5,7-tetrazocine-2,6-(1H,3H)-dione was prepared in a good yield, and its crystal structure was determined by means of X-ray analysis. The molecule is centrometric. It has practically a planar structure except for four methyl groups and two methylene linkages and a hole of 0.5–1.6 Å in the interior of the ring structure.
A Convenient Synthesis of 3-Cyano-2-methylpyridines under Ultrasonic Irradiation
Authors: Shibata Katsuyoshi , Urano Katsuyoshi , Matsui Masaki
Published: July 2006

Ultrasonic irradiation of α,β-unsaturated carbonyl compounds 1a–i with acetonitrile in the presence of potassium t-butoxide gave 3-cyano-2-methylpyridines 2a–i in moderate to good yields. The pyridines are produced by a Michael reaction of 3-iminobutanonitrile, an acetonitrile dimer, to the substrates 1a–i.
Volume of Mixing in the Liquid Bismuth–Lead System
Authors: Badawi Walid Ahmad
Published: July 2006

The results obtained in determining the volume of mixing vm in the liquid Bi–Pb system at 660 K using the pycnometer method indicate the compound Pb3Bi2 at the composition 0.6. The shifting of the slight positive vmaxm to the composition 0.4 is attributed to a nonlinear Wagner effect.
Raman Spectral Characteristics of Cobalt(III) Complexes with Quadridentate Ligands
Authors: Kawamoto Tatsuya , Hidaka Jinsai , Einaga Hisahiko
Published: July 2006

The Raman spectra of cobalt(III) complexes with quadridentate ligands such as triethylenetetramine (trien), ethylenediamine-N,N′-diacetate (edda), tris(2-aminoethyl)amine (tren), and N-(2-aminoethyl)iminodiacetate (aeida), were measured for the skeletal vibration region of 200–700 cm−1 in order to obtain general information on the relation between the spectra and the structures of these complexes. The Raman bands can be classified into four vibration modes; a totally symmetric stretching vibration mode in the 420–670 cm−1 region, a stretching vibration mode excluding the totally symmetric one in the 390–450 cm−1 region, a metal-ligand skeletal bending deformation mode in the 300–420 cm−1 region, and the chelate ring deformation mode in the 240–290 cm−1 region. The skeletal vibrations of cis-α and cis-β isomers of the cobalt(III) complexes with linear quadridentate ligands correspond to those of the tris(bidentate)cobalt(III) and the mer isomers of bis(terdentate)cobalt(III) complexes, respectively. In addition, the skeletal vibrations of the cobalt(III) complexes with tripodlike quadridentate ligands also correspond to those of the mer isomers of bis(terdentate)cobalt(III) complexes. The Raman spectra of the present complexes depend primarily on the configuration of the quadridentate ligands and the effect due to the bidentate ligands is of secondary importance.
Syntheses and Properties of Dipyridylnorbornadienes
Authors: Yamashita Yoshiro , Hanaoka Takaaki , Takeda Yasuyuki , Mukai Toshio , Miyashi Tsutomu
Published: July 2006

2,3-Dipyridylnorbornadienes were prepared using the Diels–Alder reaction of the HBF4 salts of dipyridylacetylenes with cyclopentadiene. Their absorptions extend to 380 nm and are red-shifted in an acidic media. They underwent photocyclization to give quadricyclanes which reverted to norbornadienes upon heating or encountering a Co(II)–TPP catalyst. 2,3-Bis(1-methylpyridinio)norbornadienes were also prepared by a Diels–Alder reaction of bis(1-methylpyridinio)acetylenes with cyclopentadiene. Irradiation of 1-methyl-2-pyridinio and 1-methyl-3-pyridinio derivatives led to the photostationary state between them and the corresponding quadricyclanes, while a 1-methyl-4-pyridinio derivative gave a water or methanol adduct in the presence of water or methanol. Electron-transfer reactions of bis(1-methylpyridinio)norbornadienes were investigated by cyclic voltammetry. The radical cations formed by their reduction were unstable compared with those of the corresponding trans-bis(1-methylpyridinio)ethylenes. Steric factors were shown to strongly affect the reactivities.
The Preparation of Photoresponsive Cyclobutanocrown Ethers by Means of Intramolecular [2+2]Photocycloaddition
Authors: Akabori Sadatoshi , Kumagai Takeshi , Habata Yoichi , Sato Sadao
Published: July 2006

The reaction of o-bis(3-hydroxy-1-oxapropyl)benzene (7b) with 3,3′-(trimethylenedi-4,1-phenylene)bis[2-propenoyl chloride] gave 8,9-benzo-4,7,10,13-tetraoxa[16.3]paracyclopha-1,8,15-triene-3,14-dione (8b) in a 6.5% yield, together with its dimer in a 12.3% yield. Also, 5,6-benzo-4,7-dioxa[10.3]paracyclopha-1,5,9-triene-3,8-dione (8a) and 11,12-benzo-4,7,10,13,16,19-hexaoxa[22.3]paracyclopha-1,11,21-triene-3,20-dione (8c) were obtained by the same method in 7.0 and 8.0% yields, together with their respective dimers (9a: 6.0%, 9c: 10.8%). X-Ray analysis of 8b revealed the two double bonds to be trans and the distances between the two olefinic carbon atoms (C17–C35) and (C18–C34) to be 5.341(11) and 5.906(9) Å respectively. These distances are too long for intramolecular [2+2]photocycloaddition to occur in the crystalline state. However, the irradiation of the solutions of the crown ethers 8a and 8b in acetonitrile by Pyrex-filtered UV light (>300nm) gave two intramolecular [2+2]photocycloadducts, cyclobutanocrown ethers 10a and 10b, in 95.7 and 91.8% yields respectively. Subsequently, 10a and 10b were transformed to 8a and 8b in 37 and 29% yields respectively upon irradiation with 220 nm UV light. The structures of 10a and 10b were confirmed to be the β-form.
Water-Soluble Acylating Agents: Preparation of 2-Acylthio-1-alkylpyridinium Salts and Acylation of Phenols, Acids, and/or Amines with These Salts in an Aqueous Phase
Authors: Sakakibara Tohru , Watabe Yukie , Yamada Masahide , Sudoh Rokuro
Published: July 2006

Reaction of phenols, amines, and acids with 2-benzoylthio-1-methylpyridinium chloride prepared in situ from benzoyl chloride and 1-methyl-2(1H)-pyridinethione, afforded the corresponding benzoyl derivatives in good yields. In the reaction of p-nitrophenol, even a catalytic amount of 1-methyl-2(1H)-pyridinethione proved to be effective. Similar reactions of p-nitrophenol with isobutyryl chloride and acetyl chloride in the presence of 1-methyl-2(1H)-pyridinethione afforded p-nitrophenyl isobutyrate and p-nitrophenyl acetate in 63 and 44% yields, respectively. 2-Benzoylthio-, 2-acetylthio-, and 2-isobutyrylthio-1-ethylpyridinium tetrafluoroborates were prepared by treatment of the corresponding 2-acylthiopyridines with triethyloxonium tetrafluoroborate. These pyridinium salts also acted as acylating agents in an aqueous phase. Some competitive reactions of 2-aminoethanol and phenols with 2-benzoylthio-1-methylpyridinium chloride were also investigated.
The Knoevenagel Reactions of Aldehydes with Carboxy Compounds. I. Reactions of p-Nitrobenzaldehyde with Active Methine Compounds
Authors: Tanaka Mayumi , Oota Osamu , Hiramatsu Hideo , Fujiwara Kazuyoshi
Published: July 2006

The Knoevenagel reactions of p-nitrobenzaldehyde (1) with β-keto acids, methylmalonic (2a) and α-methylacetoacetic acids (2b) were carried out in the presence of a tertiary amine such as pyridine. We have isolated the corresponding β-hydroxy intermediate (3a) by the reaction of 2a which positively suggested the reaction proceeded by the Hann and Lapworth mechanism. A kinetic study using 1H NMR revealed the existence of the reversibility between the starting materials and the β-hydroxy intermediate and that the rate determining step was decarboxylattion. But, when using the secondary amine, both the β-hydroxy acid and the corresponding condensation product were obtained via this reaction. These findings led to the conclusion that the reaction proceeded according to the two competing mechanisms, i.e., the Hann and Lapworth and Knoevenagel mechanisms. It was further clarified that either the decarboxylation step or the formation of the bis(dialkylamino) derivative was the rate determining step. The stereoselectivity of the β-hydroxy saturated compound has been closely related to the fact that the conformation of the intermediate possesses an intramolecular hydrogen bond to a hydroxyl group.
Thermal and Ferroelectric Properties of Novel Ferroelectric Liquid Crystals Containing α-Methylcinnamoyl Moiety in the Core Structure
Authors: Nakauchi Jun , Kageyama Yoshitaka
Published: July 2006

Six homologous series of novel ferroelectric liquid crystals containing α-methylcinnamoyl moiety in the core structure:

(Remark: Graphics omitted.)

(IA: k=1, l=1, (Remark: Graphics omitted.), n=8–16; IB: k=1, l=1, (Remark: Graphics omitted.), n=8–16; IIA: k=1, l=2, (Remark: Graphics omitted.), n=9–16; IIB: k=1, l=2, (Remark: Graphics omitted.), n=8–14, IIIA: k=2, l=1, (Remark: Graphics omitted.), n=9–16; IIIB: k=2, l=1, (Remark: Graphics omitted.), n=9–16) have been synthesized and their thermal and ferroelectric properties have been investigated. The mesomorphic transition temperatures and the spontaneous polarization for the homologous series (IA, IB, IIA, IIB, IIIA, and IIIB) depend on the core structure, the chiral group, and the terminal alkoxyl chain length. These homologous series show the chiral smectic C phase over wide temperature ranges including room temperature and the values of their maximum spontaneous polarization are in the range of 30 to 800 μCm−2. The thermal stability of the mesophase and the magnitude of the spontaneous polarization have been discussed from the view point of the molecular structure and the local molecular interactions.
A New Method for Determining Cyclodextrin Complex Formation Constants with Electrolytes in Aqueous Medium
Authors: Sanemasa Isao , Fujiki Motohisa , Deguchi Toshio
Published: July 2006

By making use of the volatilization rate of iodine from aqueous into gaseous phase, association constants of α-cyclodextrin with electrolytes (chlorides, nitrates, and perchlorates) have been determined at 25 °C; the counter cations are found to be largely responsible for the association.
Electrochemical Oxidation of Ruthenium and Iron Complexes at Rotating Disk Electrode in Acetonitrile Solution
Authors: Morita Masayuki , Tanaka Yoshinori , Tanaka Keisuke , Matsuda Yoshiharu , Matsumura-Inoue Takeko
Published: July 2006

The diffusion coefficient and the apparent rate of charge-transfer have been determined for various ruthenium and iron complexes in an acetonitrile solution by using a rotating disk electrode (RDE) method. The diffusion coefficients of [Ru(bpy)3]2+, [Ru(acac)3], and [Fe(bpy)3]2+ (bpy: 2,2′-bipyridine, acac: acetylacetone), being similar to each other, were about 2×10−10 m2 s−1 in acetonitrile containing 0.1 mol dm−3 (C2H5)4NBF4. The apparent rate of electrochemical oxidation increased in the order [Ru(bpy)3]2+<[Ru(acac)3]<[Fe(bpy)3]2+. The order of the rates was reciprocal to the order of their oxidation potentials in the same electrolyte.
Permeability Control of Polyelectrolyte Complex Membrane Including Chitosan Derivative as a Component
Authors: Kikuchi Yasuo , Kubota Naoji
Published: July 2006

The properties of polyelectrolyte complexes (PEC) and PEC membranes were investigated in the systems of glycol chitosan (GC)–poly(vinyl sulfate) (PVSK) and methyl glycol chitosan (MGC)–(carboxymethyl)dextran (CMD). The degree of dissociation and the conformation of GC and CMD depend upon pH, because GC and CMD are weak polybase and weak polyacid, respectively. On the basis of this knowledge, a research into the pH dependence of dissociation and viscosity of GC and CMD was carried out. PEC including chitosan derivative as a constituent was synthesized at the adequate pH, pH 3.0 in the GC–PVSK system and pH 7.0 in the MGC–CMD system. PEC membranes were prepared, and the permeability of KCl, urea, and sucrose through the GC–PVSK membrane was determined under various pH. It was revealed that the permeability of KCl, urea, and sucrose varies with the solution pH. The permeability in the neutral region was 2–10 times as high as that in acidic region. The increase of permeability in neutral region was considered from IR spectra of membranes to be due to swelling caused by a conformational change.
Terplex Formation in the Excited Triplet State. The Chloranil and Mesitylene System
Authors: Kobashi Harumichi , Hiratsuka Ken-ichi , Motegi Kazuaki
Published: July 2006

The enthalpy and entropy changes have been estimated for the formation of a triplet-state (1:2) terplex as well as an ordinary (1:1) exciplex between triplet chloranil (3CA) and mesitylene (M) in carbon tetrachloride. Results indicate that the terplex is energetically less stable than the bimolecular exciplex, while the stabilization of the terplex is compensated by the positive entropy change associated with transformation from the exciplex to the terplex.
Development and Applications for the Simulater of Intermolecular Potentials. II. Hydration Effects on the Conformation of Tyramine
Authors: Takagi Tatsuya , Tanaka Akito , Tani Mika , Maezaki Hironobu , Fujiwara Hideaki , Sasaki Yoshio
Published: July 2006

Conformational energy maps of the tyramine monocation and its hydrated species were calculated using the SIMP system. The populations of the trans conformer were calculated to be 18% and 53% for the isolated monocation and the hydrated one respectively. The computational results was supported by the results of conformational analysis based on 1H NMR spectroscopy.