bluuebunny/crossref_metadata_2025 huggingface dataset:
Structural Study of Optical Resolution. XVI. The Crystal Structures of a Pair of Diastereomeric Salts of the lel3-Tris(trans-1,2-cyclohexanediamine)nickel(II) Complex with d-Tartrate Dianion
Authors: Mizuta Tsutomu , Miyoshi Katsuhiko
Published: July 2006

The crystal structures of the diastereomeric salt pair, Λ-lel3-[Ni(S,S-chxn)3](d-tart)·3H2O (1) and Δ-lel3-[Ni(R,R-chxn)3](d-tart)·5H2O (2) (chxn=trans-1,2-cyclohexanediamine and d-tart=(+)-(R,R)-tartrate dianion), have been determined by single-crystal X-ray diffraction techniques. Crystal 1 is orthorhombic with the space group P212121, a=10.093(2), b=13.589(4), c=22.011(4) Å, and Z=4. Crystal 2 is also orthorhombic with the same space group, a=11.197(2), b=13.102(2), c=22.402(2) Å, and Z=4. In 1, the d-tart ion makes a familiar face-to-face contact with the Λ complex, in which the two alcoholic and one carboxylic O atoms of the d-tart ion are involved in the multiple hydrogen bonds to the three H–N groups on the triangular face of the complex. This contact mode resembles the one found earlier in the chloride d-tart salt of the corresponding Λ Co(III) complex, Λ-lel3-[Co(S,S-chxn)3]Cl(d-tart)·2H2O (3). On the other hand, no such face-to-face contact is present in 2, though it has been found in the corresponding Δ Co(III) complex salt, Δ-lel3-[Co(R,R-chxn)3]Cl(d-tart)·2H2O (4) in which the d-tart ion is obliged to rotate the distal carboxylato group so as to avoid the steric repulsion otherwise imposed on it by one of the bulky chxn ligands. Detailed comparison of the above four crystal structures revealed that the packing modes of the respective complex cations and counterions are surprisingly similar to one another, indicating that the absence of such a face-to-face contact in 2 is attributed to the weaker affinity of the d-tart ion for the divalent Δ Ni(II) complex, rather than to the steric demands of the crystal packing in 2. In 2 are found two deformed contact modes similar to each other, in which the d-tart ion directs its three O atoms to the triangular face, but only one of them is hydrogen-bonded to one or two of the three H–N groups on the triangular face. The d-tart ion thereby avoids the steric repulsion that would be imposed on it if it should make a usual face-to-face contact with the Δ complex.
Asymmetric Transformation of (RS)-2-Phenylglycine via Formation of Salt with (1S)-10-Camphorsulfonic Acid
Authors: Shiraiwa Tadashi , Sakata Shinji , Fujishima Keiko , Kurokawa Hidemoto
Published: July 2006

An asymmetric transformation of (RS)-2-phenylglycine [(RS)-Phg] was carried out via formation of a salt with (1S)-10-camphorsulfonic acid [(S)-CS] in acetic acid, propanoic acid, or butanoic acid by heating at 100 °C without using any catalysts such as aldehydes. The rate of epimerization of a more soluble salt of (S)-Phg with (S)-CS was estimated to be lowest in acetic acid and highest in butanoic acid. The asymmetric transformation in propanoic acid, however, was achieved successfully to give the salt of (R)-Phg with (S)-CS with 100% optical purity in 82% yield. Optically pure (R)-Phg was obtained from the salt in 80% yield based on the (RS)-Phg used as the starting material.
A Combined Solvent Extraction-Spectrophotometry for the Determination of Bismuth(III)
Authors: Desai Ganesh Shantilal , Shinde Vijay Malhar
Published: July 2006

A method has been proposed for the extraction of bismuth(III) at microgram level from bromide media using mesityl oxide as an extractant. The bismuth–bromo complex formed in the concentration range of 0.05–0.3 mol dm−3 hydrobromic acid showed quantitative extraction into mesityl oxide. Various experimental conditions such as acid concentration, mesityl oxide concentration, period of equilibration, stripping agents, and diverse ions have been studied. Bismuth ion after stripping is determined by thiourea spectrophotometrically. The method is applicable to the analysis of pharmaceutical samples, alloy samples, and synthetic mixtures.
Effects of Halide Ions on Micelle-Enhanced Chemiluminescence Reaction of Lucigenin with Adrenaline
Authors: Kamidate Tamio , Kaneyasu Tetsutoshi , Segawa Tadashi , Watanabe Hiroto
Published: July 2006

A remarkable lowering of chemiluminescence (CL) emitted from the CL reaction of lucigenin (Luc) with adrenaline (AD) was observed in cationic micellar assemblies containing halide ions, when their concentrations were above 5×10−3 mol dm−3. These results could be explained in terms of the quenching of the Luc CL reaction by halide ions. The quenching by chloride ions was dependent on the carbon number in the alkyl group of surfactant reagents.
Palladium-Catalyzed Carbonylative Cross-Coupling Reaction of 1-Halo-1-alkenes with 9-Alkyl-9-BBN Derivatives. A Direct Synthesis of α,β-Unsaturated Ketones
Authors: Ishiyama Tatsuo , Miyaura Norio , Suzuki Akira
Published: July 2006

The synthesis of α,β-unsaturated ketones by means of the palladium-catalyzed cross-coupling reaction between 9-alkyl-9-borabicyclo[3.3.1]nonanes (9-R-9-BBN) and 1-halo-1-alkenes under carbon monoxide atmosphere is described.
Dielectric Relaxation Studies of Oligether of Ethylene Glycol at Microwave Frequencies
Authors: Purohit Hari Dutt , Sengwa Ram Jeewan
Published: July 2006

Dielectric relaxation studies of dialkyl ethers of ethylene glycol and of diethylene glycol have been carried out at microwave frequencies in benzene solutions. Dipole moment and relaxation times corresponding to overall and group rotations and their weight factors have been determined. The configuration of these molecules and the mechanism of the rotation of end alkoxyl groups have been discussed.
Observation of Propagation Speed of Conductive Front in Electrochemical Doping Process of Polypyrrole Films
Authors: Tezuka Yoshihiko , Ohyama Shigeru , Ishii Tadahiro , Aoki Koichi
Published: July 2006

According to the propagation theory of a conductive zone for the electrochemical doping process of conducting polymer films, an oxidized conductive zone works as an electrode for oxidizing the reduced non-conductive region and is propagated throughout the film under charge transfer control. This theory was verified for polypyrrole films by tracing the temporal and spatial variations of conductive regions in a film. An exhaustively reduced polypyrrole film was laid on an insulating glass plate and connected electrically to an ITO electrode at the marginal part. The film absorbance to a monochromatic light beam was monitored with a photodiode array detector at 14 segments of the film. When the potential of the ITO electrode was stepped to an oxidation potential of the film, an electrochemically oxidized conductive zone was propagated through the film with a manifest phase boundary. The distance from the edge of the ITO electrode to the front of the conductive zone increased linearly with time. The logarithmic slope of the propagation speed exhibited a linear relation to the applied potential.
Pressure-Induced Neutral–Ionic Phase Transition of a Tetrathiafulvalene–Iodanil Crystal
Authors: Matsuzaki Susumu , Hiejima Toshihiro , Sano Mizuka
Published: July 2006

The pressure dependence of IR spectra measured for a mixed-stack neutral charge-transfer (CT) crystal, tetrathiafulvalene–iodanil (TTF–IA), showed an occurrence of a neutral–ionic (N–I) transition at 1.9 GPa. The N-I transition is accompanied by gradual dimerization of the crystal lattice and a small ionicity jump, in contrast to the case of TTF–chloranil (TTF–CA). Such a quasi-continuous N–I transition is attributable to stronger electron–lattice interaction in TTF–IA than that in TTF–CA.
Direct Epoxidation of Olefins Catalyzed by Nickel(II) Complexes with Molecular Oxygen and Aldehydes
Authors: Yamada Tohru , Takai Toshihiro , Rhode Oliver , Mukaiyama Teruaki
Published: July 2006

In the presence of a bis(1,3-diketonato)nickel(II) complex, various olefins are directly monooxygenated into the corresponding epoxides on treatment with atmospheric pressure of oxygen or air and aldehydes. Especially, it is noted that bis[1,3-bis(p-methoxyphenyl)-1,3-propanedionato]nickel(II) behaves as an excellent catalyst in the present epoxidation.
Asymmetric Reactions of Enamines with Methyl (E)-4-Oxo-4-(2-oxo-1,3-oxazolidin-3-yl)-2-butenoate by the Use of a Chiral Titanium Reagent
Authors: Hayashi Yujiro , Otaka Ken , Saito Nobuo , Narasaka Koichi
Published: July 2006

Asymmetric Michael and [2+2] cycloaddition reactions between enamines and methyl (E)-4-oxo-4-(2-oxo-1,3-oxazolidin-3-yl)-2-butenoate proceed with a chiral titanium reagent generated in situ from dichlorodiisopropoxytitanium and a tartrate-derived chiral 1,4-diol. In the presence of excess amounts of the chiral titanium reagent, good to moderate enantioselectivity is attained. The reactions are also well catalyzed even with a catalytic amount of the titanium reagent.
One-Step Hydroamidation of a Schiff Base with Trichlorosilane
Authors: Okamoto Hidenori , Kato Shozo
Published: July 2006

We have found that the treatment of a Schiff base (2) with trichlorosilane and chloroacetyl chloride results in a highly active chloroacetamide herbicide (1) in an excellent yield. This one-step hydroamidation reaction of a Schiff base is a useful synthetic method.
Crystal Structures and Electrical Conductivities of TXCn-TTF (X=Sulfur, Selenium, Tellurium; n=2,3)·TCNQ Charge-Transfer Complexes
Authors: Imaeda Kenichi , Mori Takehiko , Nakano Chikako , Inokuchi Hiroo , Iwasawa Naoko , Saito Gunzi
Published: July 2006

The crystal structures and the electrical conductivities have been studied for tetrakis(alkylchalcogeno)tetrathiafulvalene (TXCn-TTF (X=sulfur, selenium, tellurium; n=2,3)) complexes with tetracyanoquinodimethane (TCNQ). All the complexes with a composition of 1 : 1 had the same crystal system (triclinic) and the same space group (P\bar1). The donor and acceptor molecules were alternately stacked in their crystals. (TSeC2-TTF)TCNQ was obtained as plate and needle crystals. The molecular structure of TSeC2-TTF and the overlapping mode between TSeC2-TTF and TCNQ molecules of the two complexes were subtly different. All the complexes were semiconductors because of their mixed-stack structures. (TTeC2-TTF)TCNQ showed the lowest resistivity (5 Ω, cm at room temperature). Its good conductivity was brought about by the effective degree of charge-transfer and the favorable overlap between TTeC2-TTF and TCNQ molecules. An overall discussion on the structural and physical properties of a series of TCNQ complexes with TXCn-TTF (X=sulfur, selenium, tellurium; n=1,2,3) is presented.
ESR Studies at High Pressures. III. Spin-Exchange Reactions of Some Nitroxide Radicals in Acetone and Hexane
Authors: Sueishi Yoshimi , Kuzukawa Masahiro , Yamamoto Shunzo , Nishimura Norio
Published: July 2006

Pressure effects on the rate of spin–spin exchange of some nitroxide radicals in acetone and hexane at 298.2 K have been studied by means of a high-pressure ESR technique. It was found that this exchange reaction is diffusion-controlled. The rate of the spin exchange is related to that of diffusion, the probability of the spin exchange, P=f(J, τ1), and steric factor fs. The values of P and hence τ1 were estimated as a function of pressure. A method for evaluating the steric factor and the exchange integral is proposed.
The Number of Organic Radicals on a Decationated Y-Type Zeolite before, during, and after Irradiating with Ultraviolet Light or Heating
Authors: Kashiwagi Hiroshi
Published: July 2006

A decationated Y-type zeolite (HY) was adsorbed by a single organic compound from a heptane solution, and dried in vacuo. The numbers of the radicals in these binary systems before, during, and after irradiating with ultraviolet (UV) light or heating were followed by electron paramagnetic resonance spectroscopy and then compared. During UV irradiation, the number of radicals increased from the constant number of spins before illumination (C1) to the second constant number of spins (C2). After stopping the illumination, the C2 decreased up to the third constant number of spins (C3). The C3 value was smaller than C2, but was significantly greater than C1. The enhancement of radicals induced by UV light, expressed quantitatively in terms of the C3/C1 ratio, was pronounced when either a weak donor or a weak acceptor was adsorbed on HY calcined at a low temperature. C1 was proportional to the amount of adsorption up to the maximal amount of adsorption, whereas C2 and C3 were proportional only at a considerably decreased amount of adsorption. A similar tendency was observed when the binary systems were heated at 40 or 80 °C. A quantitative determination of the mechanically induced enhancement of radicals would prompt either an improvement in the reproducibility of physicochemical data or an elucidation of the solid acidity or basicity.
VUV Photoionization Efficiency Curves and Appearance Energies of N,N-Dimethylformamide Ion and Its Fragment Ions
Authors: Arimura Masana , Yoshikawa Yozaburo
Published: July 2006

Ionization efficiency curves of N,N-dimethylformamide (DMF) ion and of its fragment ions, C3H6NO+, C2H4NO+, and C2H6N+ were obtained by use of vacuum ultraviolet photoionization method. The appearance energy of the parent ion was 9.12±0.06 eV. The appearance energies of C3H6NO+, C2H4NO+, and C2H6N+ were very close (10.77±0.08 eV for C3H6NO+ and C2H4NO+, 10.59±0.08 eV for C2H6N+). The relative intensity curve of C2H6N+ normalized by the sum of fragment ions vs. photon energy has the second rise at 12.2±0.3 eV, which implies that another fragmentation process appears at the photon energy above 12.2 eV. The second fragmentation process is ascribed to a channel through DMF cation in an excited electronic state.
Additional Formation of Brønsted Acid Sites on Silica–Alumina Catalyst Surfaces by Depositing Silica Component
Authors: Sato Satoshi , Hiratsuka Masahiro , Sodesawa Toshiaki , Nozaki Fumio
Published: July 2006

The chemical vapor deposition (CVD) of silica onto an amorphous silica–alumina was investigated using tetraethoxysilane in order to create Brønsted acid sites on the surface of original silica-alumina. Silica loading could be readily controlled by the CVD time at 160 °C; the silica covered an internal wall of mesopore of the support of silica–alumina. The resulting CVD silica–alumina was catalytically more active than the original silica–alumina support for such test reactions as the cracking of cumene and the isomerization of 1-butene. The characteristic changes in the amount of Brønsted acid sites were clarified by means of the temperature-programmed desorption of adsorbed 2,6-dimethylpyridine. Strong Lewis acid sites of the original silica–alumina were converted into strong Brønsted acid sites upon depositing the silica component.
Pillared Tetrasilicic Mica Catalysts Having Fixed Interlayer Ca Ions. Comparison with Other Clays
Authors: Sakurai Hiroaki , Urabe Kazuo , Izumi Yusuke
Published: July 2006

Three kinds of Ca2+-modified pillared clays (TSM, taeniolite, and montmorillonite) were prepared from Ca2+-exchanged clays. The cumene cracking activity over the TSM-based catalyst was greatly dependent on the calcination temperature before pillaring, and gave a maximum at 300–400 °C. In contrast, no appreciable increase in the activity with the calcination temperature before pillaring was observed in montmorillonite- and taeniolite-based catalysts. The amount of residual Ca in the modified pillared TSM was increased with a rise in the calcination temperature before pillaring, whereas the amount of Al incorporated through pillaring was decreased, showing the progress of Ca2+ fixation during the stage of thermal treatment of Ca2+-exchanged unpillared TSM. Thus, the cracking activity was greatly enhanced by the fixation of Ca2+. The cracking activity, however, dropped due to a pretreatment above 400 °C, since the Al-pillars which prop silicate layers are reduced while causing a decline in the surface area of the resulting pillared TSM; also, the strong acid sites were decreased due to excessive packing of Ca2+ fixed over the surface of silicate layers. In the cases of montmorillonite and taeniolite, the remaining amounts of Ca and Al were almost constant, irrespective of the calcination temperature before pillaring. This indicates that Ca2+ fixation does not occur in these clays.
Reaction of Tris(t-butylthio)cyclopropenylium Perchlorate with Arylmagnesium Bromides
Authors: Kojima Hideo , Ozaki Kazuyoshi , Matsumura Noboru , Inoue Hiroo
Published: July 2006

The reaction of tris(t-butylthio)cyclopropenylium perchlorate with phenyl-, o-tolyl-, or 1-naphthylmagnesium bromide in tetrahydrofuran at room temperature gave t-butylthio-substituted allenes and indenes. The reaction with 2,6-xylylmagnesium bromide gave only the corresponding allene derivative.
Resonance Raman Study on Phot on eduction of Iron–Porphyrins. A Novel Insight into the Ligand-Aided Process
Authors: Fidler Vlastimil , Ogura Takashi , Sato Shin-ichiro , Aoyagi Katsuhiro , Kitagawa Teizo
Published: July 2006

Photoreduction of Fe(OEP) (OEP: octaethylporphyrin) in organic solvents by visible light was demonstrated to be a ligand-aided process in which simultaneous coordinations of a base such as 2-methylimidazole (2MeIm) and of an aliphatic alcohol to two axial positions of the iron ion were required. Coordination of an alcohol was evidenced from the observation of the Fe–alcohol stretching (νFe–alcohol) resonance Raman (RR) band. Since this band exhibited an appreciable frequency shift between ROH and ROD, coordination of the alcohol in a protonated form was suggested. When a primary or secondary alcohol was added to the CH2Cl2 solution of FeIII (OEP)Cl in the presence of 2MeIm, a new absorption band appeared around 560–590 nm and the νFe–alcohol RR band was most intense for excitation at the maximum of the new absorption band. The new absorption was therefore assigned to the alcohol to FeIII charge transfer (CT) band. A tertiary alcohol gave neither the CT band nor the νFe–alcohol RR band, although some spectral changes were noticed after long laser illumination at 441.6 nm, and the photoreduction as seen for other alcohol solutions did not take place. This photoreduction was not apparently recognized in the presence of oxygen. However, flash photolysis experiments demonstrated that the photoreduction occurs irrespective of the presence or absence of oxygen but rapid reoxidation results in apparent no effect.
Reaction of Thioaldehydes with Amines
Authors: Okuma Kentaro , Komiya Yasuo , Ohta Hiroshi
Published: July 2006

The reaction of phosphonium ylides with elemental sulfur gave thioaldehydes, which changed to the corresponding thioamides in good yields when treated with amines. When thioaldehydes containing α-hydrogens were treated with secondary amines, the corresponding enamines or reduction products were obtained.
Catalysis by Heteropoly Compounds. XVIII. Oxidation of Methacrylaldehyde over 12-Molybdophosphoric Acid and Its Alkali Salts
Authors: Mizuno Noritaka , Watanabe Tetsuji , Misono Makoto
Published: July 2006

The reaction scheme for the methacrylaldehyde oxidation over heteropoly compounds proposed previously (M. Misono et al., Proc. 7th Intl. Congr. Catal., 1980) was confirmed by 18O tracer experiments using the Pulse-MS method (combination of pulse reactor/mass spectrometer). The occurrence of direct and rapid oxygen exchange between methacrylaldehyde and the polyanion of MxH3−xPMo12O40 (M=Na, Cs, x=0–3.15) was verified under the reaction conditions. The results also suggested that this reaction is catalyzed by Brønsted acid sites of the catalysts via such intermediates as (I) and/or (II) in scheme 1. It was shown that the methacrylaldehyde oxidation is a surface-tyepe reaction and the catalytic activity is controlled by the oxidizing ability of the catalyst surface.
Raman Phonon Spectroscopic Study of Phase Transition in trans-Stilbene Crystal
Authors: Chakrabarti Subhasis , Misra Tridibendra Narayan
Published: July 2006

Raman phonon spectroscopy in the 10–170 cm−1 range has been used to study phase transition in trans-stilbene crystal. At 77 K, eight distinct phonon modes and an internal mode are observed whereas at 300 K the spectrum shows only four phonon bands and an internal mode. The temperature dependence of spectral pattern and some phonon band width suggest that the phase transition in this crystal is quasi-continuous over a small temperature range 215–225 K. The absence of a soft mode and a strong increase of the phonon band width, when approaching the Tc from below, suggest that the phase transition is of order-disorder type. The well established disordered structure of trans-stilbene crystal at room temperature attains an ordered structure at low temperature at least through one, possibly two order–disorder transitions.
Structure and Properties of (NEt4)[MoVO(α,2-toluenedithiolato)2]. Distorted Tetragonal-Pyramidal MoOS4 Core
Authors: Ueyama Norikazu , Yoshinaga Naoto , Kajiwara Atsushi , Nakamura Akira , Kusunoki Masami
Published: July 2006

An oxomolybdenum(V) complex with two chelating ligands of alkane- and arenethiolate parts, (NEt4)[MoVO(α,2-toluenedithiolato)2], was prepared and characterized by visible, ESR, IR, and Raman spectroscopies. Four distinct ligand-to-metal charge transfer absorption bands were observed in visible region. The complex crystallizes in the space group P21 with a=9.535(2), b=16.582(9), c=8.085(1) Å, β=90.757(4)°, V=1278.3(8) Å3, Z=2, and dcalcd=1.431 g cm−3. The structure was solved and refinement based on 2102 reflections converged at R=0.089 and Rw=0.100. The complex takes an apical oxo and trans bis(α,2-toluenedithiolato) structure with a distorted MoOS4 core from a tetragonal-pyramidal geometry.
Dipeptide Side Chain–Side Chain Hydrophobic Interactions as Conformational Core for Chymotrypsin Inhibition
Authors: Sakamoto Hiroshi , Shimohigashi Yasuyuki , Ogawa Tomohisa , Kawano Keiichi , Ohno Motonori
Published: July 2006

A series of dipeptides with the sequence of H–d-Leu–l-Phe–R, where R denotes 4-phenylpiperidide, 4-phenylpiperazide, and their derivatives, have been synthesized to examine their ability to inhibit chymotrypsin. Dipeptide phenylpiperidide and phenylpiperazide inhibited chymotrypsin fairly strongly (Ki=7.5×10−4 M and 1.4×10−3 M, respectively) (1 M=l mol dm−3), while their phenyl-substituted analogs were inactive. In high resolution 3H NMR measurements, it was found that the proton signals of d-Leu γ-CH and β-CH2 shifted considerably to the upfield when compared with those of H–d-Leu–l-Ala–OH, suggesting that these upfield shifts are due to the magnetic anisotropy effect by the benzene ring of the Phe residue. This was confirmed by measuring NOE between d-Leu–isobutyl and l-Phe–phenyl groups. These NMR data indicate that the side chains of both d-Leu and l-Phe are in close proximity, resulting in formation of a hydrophobic complex. It was suggested that, in the inhibitory conformation of dipeptides against chymotrypsin, the phenyl group of phenylpiperidide or phenylpiperazide moiety fits the S1 site, while the side chain-side chain hydrophobic complexing core fits the S2 site.
Studies on Mixed Chelates. XIX. 5-Coordinate Nickel(II) Complexes with N,N,N′,N″,N″-Pentamethyldiethylenetriainine and β-Diketonates
Authors: Shintani Noriko , Sone Kozo , Fukuda Yutaka , Ohashi Yuji
Published: July 2006

Mixed Ni(II) chelates with N,N,N′,N″,N″-pentamethyldiethylenetriamine (pmdt) and a β-diketonate (dike) such as acetylacetonate(acac), dipivaloylmethanate(dipm), pivaloyltrifluoroacetonate(pfac), trifluoroacetylacetonate(tfac) or hexafluoroacetylacetonate(hfac) were prepared, and their structure and properites were studied. X-Ray crystal analysis confirmed that [Ni(acac)(pmdt)]ClO4 is a distorted square pyramidal complex, and the solid reflection spectra of the remaining chelates indicated that most of them are also essentially square pyramidal. This structure is retained in a nonpolar solvent like 1,2-dichloroethane, but in strong donor solvents like DMSO or DMF it is converted into a 6-coordinated structure, [Ni(dike)(pmdt)(Solvent)]+, containing a solvent molecule. The formation of this species is favored by increasing donor number(DN) of the solvent, and in the following order of dike:dipm<acac<<tfac, pfac<<hfac, which is almost opposite to the order of their pKa values.
The Excited-State Dipole Moment of Nitrobenzene Estimated from Solvent Spectral Frequency Shifts
Authors: Abe Takehiro
Published: July 2006

The excited-state dipole moment of nitrobenzene has been estimated to be 33.7×10−30 Cm from solvent spectral frequency shifts. This value agrees well with that ((31.7±3.3)×10−30 Cm) determined from an electrooptical absorption measurement.
A Fusarubin Isomer
Authors: Tanoue Yasuhiro , Terada Akira , Umezu Yasuo
Published: July 2006

An isomer of fusarubin, 2-acetonyl-5,8-dihydroxy-7-hydroxymethyl-3-methoxy-1,4-naphthoquinone, was prepared from 2-hydroxymethyl-7-(2-hydroxypropyl)-1,4,5,6,8-pentamethoxynaphthalene.
EXAFS Investigation of Pentasil-Structured Gallium-Containing Metallosilicates
Authors: Okabe Kiyomi , Matsubayashi Nobuyuki , Sayama Kazuhiro , Arakawa Hironori , Nishijima Akio
Published: July 2006

Pentasil-Structured bimetallosilicates were prepared by adding Ga and Fe (or Sr) salts simultaneously during the hydrothermal synthesis of a pentasil silicate, and local structures around Ga were directly elucidated by means of EXAFS for the first time. It was found that Fe and Ga independently substituted the silicate framework, and that the local structure around Sr was the same as that in Sr2+-exchanged gallosilicate.
Thermodynamic Study of Brij 35 in Aquo-Polyethylene Glycol Solvents
Authors: Koshy Leena , Rakshit Animesh Kumar
Published: July 2006

The critical micelle concentrations of Brij 35 in aquo PEG 200 solutions were determined by the iodine solubilization method at five different temperatures at various PEG percents. The thermodynamic quantities of micellization as well as the free energies of micellization at infinite dilution were computed and rationalized.
Spectrophotometric Detection for Flow Injection Analysis of Tertiary Alkylamines in Terms of the Intermolecular Charge-Transfer Interaction with Iodine
Authors: Uno Bunji , Nakajima Kiho , Kawai Satoshi
Published: July 2006

Spectroscopic studies of the intermolecular charge-transfer interaction with iodine have been extended in order to develop a new spectrophotometric detection method for flow injection analysis (FIA). Tertiary alkylamines, as a model compound of spectroscopically inactive species, have been determined with high detection sensitivity by FIA using the present detection method.
Entropy Change Associated with the Charge Transfer Reation of Various Quinones in Aprotic Solvents
Authors: Komaguchi Kenji , Hatsusegawa Yasuhiro , Kitani Akira , Sasaki Kazuo
Published: July 2006

Temperature dependence of the cathodic reduction potentials of various p-benzoquinone derivatives have been determined in five aprotic solvents, benzonitrile, acetonitrile, propylene carbonate, N,N-dimethylformamide, and dimethyl sulfoxide. As for the first electron transfer reactions, the free energy of transfer between any two of solvents has been found to be less than 1.0 kcal mol−1, which is much smaller than the solvation enthalpy of ordinary anions. As a result, the transfer entropy is compensated almost perfectly by the transfer enthalpy. The compensation effect also appears in the transfer energies of the second electron transfer reaction though not perfect.
Theoretical Studies on the Potential Energy Surfaces of SO2: Electronic States for Photodissociation from the \ ildeC1B2 State
Authors: Kamiya Kenshu , Matsui Hiroyuki
Published: July 2006

The potential energy surfaces of electronically excited states of SO2 have been investigated with ab initio molecular orbital method: Especially, the two-dimensional potential energy surface for the \ ildeC1B2 (21A′) state as a function of both the bond angle and bond distance has been carefully analyzed, including the spin-orbit interaction. Energetically, 23A′ (13A1 in C2v) was found to be the most grobable state which concerns the reaction mechanism for the photodissociation pathway from the \ ildeC state (SO2 (\ ildeC1B2)→SO(3∑−)+O(3P)); however, other pathway may also be possible to go over the avoided crossing on a singlet potential surface.
Further Chemical Studies on Anisatin, a Neurotoxic Sesquiterpenoid Having a β-Lactone
Authors: Niwa Haruki , Tsukada Itaru , Nisiwaki Masanori , Yamada Kiyoyuki
Published: July 2006

By a series of chemical reactions, anisatin was efficiently converted into the key intermediate employed in the synthesis of anisatin.
Infrared Spectra and Intramolecular Hydrogen Bonding of 4-(Haloacetylamino)diphenylamines
Authors: Suezawa Hiroko , Hirota Minoru , Hamada Yoshiki , Takeuchi Isao , Kawabe Takae
Published: July 2006

Infrared NH stretching absorptions and 1H NMR chemical shifts of a series of 4-(haloacetylamino)diphenylamines were reported. The halogen atoms in haloacetamido groups are shown to participate in the intramolecular NH···X hydrogen bond. The hydrogen bond tends to be strengthened in the increasing order of atomic number of the acceptor halogen atoms.
Thermal Behavior of Alkaline-Earth Metal cyclo-Tetraphosphates
Authors: Nariai Hiroyuki , Motooka Itaru , Kanaji Yukio , Tsuhako Mitsutomo
Published: July 2006

The effect of water vapor on the thermal behavior of alkaline-earth metal cyclo-tetraphosphates, M2P4O12·nH2O (n=7.0, 3.5, 5.5, and 4.0 for M=Mg, Ca, Sr, and Ba, respectively) (P4m) was examined using DTA-TG, X-ray diffraction analysis, isothermal heating in an electric furnace, and HPLC-FIA. The calcination reaction of each P4m proceeded via ring opening of P4m with elimination of water of crystallization, followed by condensation of soluble oligophosphates (Poligo) to insoluble polyphosphates (Phigh poly). The rates of these reactions were faster for Mg2P4m than for other metal cyclo-phosphates. The decomposition of P4m was appreciably faster in humid air than in dry air, because of the availability of water for hydrolysis and for breaking the P–O–P linkage. However, the effect of water vapor from the atmosphere was not conspicuous, since the atmosphere contains enough water (theor. 20 mg L−1) for the hydrolysis of P4m. The products of calcination of Ba2P4m·4H2O were hardly influenced by water vapor from the atmosphere, because the water of crystallization was not easily released in the Ba system compared with the other metal salts.
Oxidative Dimerization of 1-Propyne on a 2-Pyridylethyl Copper Complex Fixed Silica Catalyst
Authors: Ukisu Yuji , Kazusaka Akio , Nomura Masaharu
Published: July 2006

A 2-pyridylethyl copper complex fixed silica catalyst was applied to an oxidative-coupling dimerization reaction of 1-propyne to 2,4-hexadiyne at 100 °C, which is a typical test reaction for Cu–(N base)-complex catalyst in the homogeneous phase. It was found to be highly catalytically active for this reaction compared with a conventional CuO/SiO2 catalyst. The reaction was deduced to proceed through a redox cycle of copper ions coordinated with the pyridine derivative.
Substituent Effects in the Solvolysis of p-(2-Substituted Cyclopropyl)-α-Methylbenzyl Chlorides
Authors: Kusuyama Yoshiaki , Kubo Takako , Iyo Masami , Kagosaku Tamami , Tokami Kenjiro
Published: July 2006

The solvolysis rates of p-(cis- or trans-2-substituted cyclopropyl)-α-methylbenzyl chlorides including electron-donating and electron-attracting substituents relative to a hydrogen substituent were measured in 80% aqueous acetone. The trans isomers were more reactive than the corresponding cis derivatives where cyclopropyl and phenyl groups could not get a most favorable “bisected” conformation for the cyclopropyl group to release electrons to the benzene ring. The relative rates of the trans isomers at 45°C were best correlated by means of σm values with a ρ value of −3.14 and a correlation coefficient of 0.97, indicating that the cyclopropane ring was a poor transmitter of a resonance effect. The substituent effects were analyzed by means of the LSFE equation.
Photochemical Hydroformylation of Olefins in the Cobalt-Phosphine Catalyst System
Authors: Mori Sadayuki , Tatsumi Shunji , Yasuda Masaki , Kudo Kiyoshi , Sugita Nobuyuki
Published: July 2006

Cobalt-catalyzed hydroformylation of olefins was found to proceed even at ambient temperature under UV irradiation in the presence of phosphine. Extremely high selectivity toward straight-chain aldehyde (99% in case of 1-hexene) was obtained by lowering the partial pressure of carbon monoxide at ambient temperature. A catalytic species different from the well-known species under high pressure of carbon monoxide and high temperature contributed to the highly selective formation of straight-chain aldehydes. Two photochemical processes were suggested to be involved in the photochemical hydroformylation reaction, that is, the formation of HCo(CO)3PBu3 from the cationic cobalt species, [Co(CO)3(PBu3)2]+, and then the formation of the coordinatively unsaturated hydride, HCo(CO)2PBu3.
Unusual Solvent Effect on the Cycloadditions of Aromatic Nitrile N-Oxide with Alkyl Substituted p-Benzoquinones in Ethanol–Water Systems
Authors: Inoue Yukihiko , Araki Koji , Shiraishi Shinsaku
Published: July 2006

The second-order rate constants of 1,3-dipolar cycloaddition reactions of 2,6-dichlorobenzonitrile N-oxide (1) with 2,5-dimethyl-p-benzoquinone (2a) or 2,6-diisopropyl-p-benzoquinone in various solvents at 20°C were determined by spectrophotometric method. The rate of 1 and 2a in ethanol : water=60 : 40 solution was 5.55×102 dm3 mol−1 s−1, which was fourteen folds of that in chloroform (3.9×10−3 dm3 mol−1 s−1). This solvent effect and the low solubility of the cycloadduct in aqueous ethanol were successfully applied to the cycloadduct synthesis.
Absolute Stereochemistry and Novel Ring-Opening Oxidation of Methyl (R)-2-Hydroxysterculate
Authors: Nakatani Munehiro , Hase Tsunao
Published: July 2006

A cyclopropene-ring-containing fatty acid ester, methyl (R)-2-hydroxysterculate, was isolated from Hibiscus rosa-sinensis along with methyl sterculate and malvalate. The stereochemistry of the asymmetric carbon at C-2 was determined as R by applying a dibenzoate chirality method, and a mild air oxidation afforded two conjugated enone isomers accompanying a ring opening.
Raman Spectra of N,N-Dimethylthioacetamide Adsorbed on Silver and Copper Electrode Surfaces
Authors: Loo Boon Hian , Lee Yue Guey , Kato Tamihiko
Published: July 2006

Surface-enhanced Raman (SER) spectra have been obtained from N,N-dimethylthioacetamide (DMTA) adsorbed on Ag and Cu electrode surfaces. Vibrational analysis of the SER spectra of DMTA is made in comparison to the bulk-phase Raman spectrum of DMTA, and the infrared data on Co, Cu, and Hg complexes of DMTA. It is concluded that the DMTA molecule is bonded through its S atom to Ag and Cu surfaces.
Adsorption-Induced Unusual Changes in the Electrical Conductivity of Some Ferrocene Derivatives
Authors: Bhattacharjee Ashis , Mallik Biswanath
Published: July 2006

The effects of adsorption of different organic vapors on the electrical conductivity of some ferrocene derivatives have been studied using the sandwich cell technique. A conductivity peak is observed in the plot of measured current versus temperature for a sandwich cell of powdery material with some adsorbed vapors. The dependence of the intensity of the peak and the temperature at which it appears have been studied as a function of grain size of powdery materials, heating rate, amount of adsorbed vapor, and also the nature of the adsorbed vapors. At the vapor-adsorbed state these materials show very high value of activation energy and the pre exponential factor σo (in the usual semiconduction equation). Results indicate that the adsorption is a physical adsorption. The usual mechanisms for the adsorption-induced change in conductivity and activation energy are not suitable for explaining the observed results. Adsorption induced reversible structural phase transition seems responsible for the anomalous behavior of the adsorption-induced changes in the electrical properties of these materials. The results obtained with different ferrocene derivatives have been compared with that of ferrocene and possible reason for the adsorption induced phase transition is discussed.
The Crystal Structure of (BEDT-TTF)4[Ni(CN)4]
Authors: Kawamoto Atsushi , Tanaka Masashi , Tanaka Jiro
Published: July 2006

The crystal of (BEDT-TTF)4[Ni(CN)4] (BEDT-TTF: bis(ethylenedithio)tetrathiafulvalene) belongs to the triclinic P\bar1 with the lattice constants of a=10.994(2), b=16.443(2), c=9.703(1) Å, α=97.85(1), β=115.15(1), γ=95.94(1)°. In the crystal, there exists the face to face overlap of the BEDT-TTF molecules along the [201] direction. The intermolecular interaction by the short S···S contact is also observed along the [\bar201] direction.
New Crystalline Complexes Composed of a Fatty Acid and Nicotinamide
Authors: Yokoyama Shoko , Ueda Fumio , Fujie Tadao
Published: July 2006

New crystalline complexes composed of a fatty acid (FA) and nicotinamide (NAA) at a molar ratio of 6 : 5, (FA)6(NAA)5, have been isolated. The melting points of (FA)6(NAA)5 were higher than those of the corresponding equimolar complexes, (FA)6(NAA)6.
Mechanism of Reaction of S,S-Diphenyl-S-methoxythiazyne with Thiols
Authors: Yoshimura Toshiaki , Tsukurimichi Eiichi , Sugiyama Yasuhisa , Kita Hiroshi , Shimasaki Choichiro , Hasegawa Kiyoshi
Published: July 2006

The reaction of S,S-diphenyl-S-methoxythiazyne with various thiols gave methyl sulfides. Kinetic investigations support a mechanism involving an initial protonation of the thiazyne nitrogen with thiol followed by a nucleophilic attack of thiolate anion on the methyl group.
Simple Preparation of (2,2′-Biphenylylene)phenylphosphine Oxide and Role of Triphenylphosphine Oxide as a Mediator for Formation of Biaryl Derivatives
Authors: Ogawa Satoshi , Tajiri Yoko , Furukawa Naomichi
Published: July 2006

(2,2′-Biphenylylene)phenylphosphine oxide (3) was prepared simply by the reaction of triphenylphosphine oxide (1) with phenyllithium and subsequently with aqueous hydrogen peroxide in acetic acid. The oxide 3 reacted with lithium diisopropylamide (LDA) and then with several electrophiles to afford regiospecifically ortho-substituted compounds in moderate yields, which were converted to unsymmetrical 2-and 2,3′-substituted 1,1′-biaryls and triphenylphosphine oxide (1).
Base-Induced Addition-Elimination Reactions of Electron-Deficient Vinylarenes Containing a Carbonyl or Ester Group Utilizing 4-Phenyl-3H-1,2,4-triazole-3,5(4H)-dione(PTAD)
Authors: Seguchi Kazuyoshi , Tanaka Satoko
Published: July 2006

The reaction of electron-deficient vinylarenes such as styrylketones and cinnamate with PTAD afforded double Diels–Alder products and Diels–Alder ene products; the latter underwent novel base-induced elimination of 4-phenyl-1,2,4-triazolidine-3,5-dione via a stable carbanion.
Synthetic Application of Benzothiazole Ring System as an On-Off Type of Leaving Group. Synthesis of Ketones and Carboxylic Acid Derivatives from 2-(1-Substituted 1-Hydroxyalkyl)- and 2-(1-Hydroxyalkyl)benzothiazoles
Authors: Chikashita Hidenori , Ishihara Masayuki , Takigawa Katsumi , Itoh Kazuyoshi
Published: July 2006

A synthetic and systematic use of benzothiazole ring system as an “on-off” type of leaving group was developed for the preparation of ketones and carboxylic acid derivatives from a variety of 2-(1-substituted 1-hydroxyalkyl)- and 2-(1-hydroxyalkyl)benzothiazoles (off state) via the corresponding benzothiazolium salts (on state) obtained by the quaternization (on switch). A variety of 3-methyl-2-(1-substituted 1-hydroxyalkyl)benzothiazolium iodides (1) underwent a carbon–carbon bond cleavage at the 2-position to give the corresponding ketones on the simple treatment with a base under mild reaction conditions. The similar reaction of 3-methyl-2-(1-hydroxy-alkyl)benzothiazolium iodides (2) to aldehydes proceeded less efficiently. The oxidative reaction of a variety of 2 with base and nonactivated MnO2 in ethanol afforded the corresponding ethyl esters. This type of oxidative reaction could be also achieved in THF with different nucleophiles such as alcohol, water, thiol, and amine to give the corresponding ester, carboxylic acid, thioester, and amide, respectively.
Effect of Bromotrifluoromethane on the Ignition in Methane and Ethane–Oxygen–Argon Mixtures behind Shock Waves
Authors: Suzuki Akimichi , Inomata Tadaaki , Jinno Hiroshi , Moriwaki Takao
Published: July 2006

The ignition delay times behind shock waves in CH4–, and C2H6–O2–Ar systems containing CF3Br were measured for a range of temperatures between 1400 and 2100 K and pressures between 1.5 and 3.5×105 Pa. These measurements indicated that CF3Br promotes the ignition of CH4 but inhibits the ignition of C2H6. Although the inhibition effect for C2H6 increases with increasing CF3Br concentration and decreasing temperature, the promotion effect in CH4 was independent of both the CF3Br concentration and the temperature in this experiment. We calculated the induction times for conditions similar to the experiments using a model which included 49 elementary reactions related to CF3Br. Calculations using this model gave induction times that were in good agreement with the experiments. The calculated values, however, depended on several effective reactions among the 49 reactions.
Triplet Intermediates in Cis– Trans Photo-isomerization of 3-Chrysenylethylenes
Authors: Karatsu Takashi , Hiresaki Tatsuro , Arai Tatsuo , Sakuragi Hirochika , Tokumaru Katsumi , Wirz Jakob
Published: July 2006

The effect of substitution of 3-chrysenyl group (Ar) on unsaturated double bonds in their triplet sensitized isomerization was investigated for Ar–CH=CH–R, R=′Bu (BC) and Ph (SC) by means of stationary irradiations, laser flash photolyses, and MO calculations. Both olefins undergo mutual isomerization between their cis- and trans-isomers. However, BC has a unique triplet energy surface with two decay funnels at the planar trans (3t*) and twisted (3p*) conformations, which are in equilibrium with each other; 3t* undergoes either unimolecular decay to the ground-state trans isomer or triplet energy transfer to the cis isomer (quantum chain process) and 3p* decays to the ground state to give the cis and trans isomers. Tn←T1 absorptions observed for BC and SC are mainly attributed to 3t* and 3p*, respectively, on the basis of semiempirical MO calculations. The populations at 3t* and 3p* are estimated.
Oxidation Using Quaternary Ammonium Polyhalides. VIII. Oxidation of 1,4-Benzenediols with Benzyltrimethylammonium Tribromide
Authors: Kajigaeshi Shoji , Morikawa Yukihiro , Fujisaki Shizuo , Kakinami Takaaki , Nishihira Keigo
Published: July 2006

The reaction of 1,4-benzenediols with 1.1 equiv of benzyltrimethylammonium tribromide in dichloromethane in the presence of aqueous sodium acetate at room temperature gave 2,5-cyclohexadiene-1,4-diones in good yields. On the other hand, the reaction of 1,4-benzenediols with a large excess of the reagent in aqueous acetic acid at 40–60°C gave polybromo-substituted 2,5-cyclohexadiene-1,4-diones in good yields.
Kinetic Studies of Oxygen Atom Transfer Reactions between Various cis-Dioxobis(dithiocarbamato)molybdenum(VI) Complexes and Triphenylphosphine
Authors: Unoura Kei , Kato Yoshikiyo , Abe Katsuaki , Iwase Akio , Ogino Hiroshi
Published: July 2006

The kinetics of the oxygen atom transfer reactions between cis-[MoO2(R2dtc)2] [R=CH3, C2H5, i-C3H7, i-C4H9, C6H5CH2 (Bz), C6H5 (Ph)] and PPh3 (coupled reactions 1 and 2) have been investigated.

[MoO2(R2dtc)2]+PPh3\xrightarrowk1[MoO(R2dtc)2]+OPPh3 (1)

[MoO2(R2dtc)2]+MoO(R2dtc)2]\oversetKd\ightleftharpoons[Mo2O3(R2dtc)4] (2)

The rate constants (k1) of oxygen atom transfer reaction 1 correlate with the formal potentials of [MoO2(R2dtc)2]0⁄−1 except for R=Bz and Ph. The equilibrium constant values (Kd) of dimerization reaction 2 decrease with increase of the electron-donating ability of the substituents on the dithiocarbamate ligands.
The Reaction of 2-Substituted Cycloalkanones with Aldehydes under Acidic Conditions
Authors: Sato Tadashi , Hayase Kengo
Published: July 2006

The title reaction proceeded with either ring enlargement or bicyclic compound formation, as well as the aldol reaction, depending upon the types of the reactants and reaction conditions.
Determination of the Absolute Configuration and Enantiomeric Purity of Allylic and Acetylenic Alcohols
Authors: Yasuhara Fujiko , Yamaguchi Shozo , Takeda Masayuki
Published: July 2006

The relative magnitude of steric bulk of saturated vs. unsaturated substituents in the title compounds has been estimated by a lanthanoid induced shift (LIS) study of these (R)-(+)-α-methoxy-α-(trifluoromethyl)phenylacetate esters [(R)-(+)-MTPA esters] by 1H NMR spectroscopy:

CH2=C(Me)−>Pentyl>n−Pr>Et\simeqCH2=CH−>Me>CH≡C−;Ph>Cyclohexyl

These results allow the assignment of the absolute configurations of both cyclic and acyclic unsaturated alcohols. Furthermore, the relative intensity of well-separated OMe signals for those diastereomeric MTPA esters can be used for the determination of the %ee of the original alcohols.
Laser Photolysis Studies on [2+2]-Photocycloreversion and Photoisomerization Reactions of trans- and cis-1,2-Di(1-pyrenyl)cyclobutane Dimers through Radical Ion Intermediates
Authors: Tsuchida Akira , Yamamoto Masahide , Nishijima Yasunori
Published: July 2006

Transient radical ion intermediates of [2+2]-photocycloreversion and photoisomerization reactions of the 1-vinylpyrene (1) cyclobutane dimers, trans- and cis-1,2-di(1-pyrenyl)cyclobutanes (2t and 2c, respectively), were studied by nanosecond laser photolysis measurements; the reaction quantum yields were determined by photoproduct analysis. The excited singlet state of dimers 2t and 2c was quenched by an electron acceptor, 1,4-dicyanobenzene, with a diffusion-controlled rate in a polar acetonitrile solvent. The transient absorption spectra of the dimers in the system showed the formation of a dimer radical cation of pyrene chromophores, whose positive charge was delocalized in the two pyrene rings. The dimers were cleaved to form 1 through the dimer radical cation. By contrast, the formation of a dimer radical anion could not be observed in quenching by an electron donor, N,N-dimethyl-p-toluidine. The cleavage yield of the dimers from the anionic species was low. The decrease in the electron density in the cyclobutane bond in the cationic state promotes the cycloreversion reaction of dimers. In the absence of an electron donor or acceptor in the nonpolar benzene solvent, the direct photocleavage of 2t and 2c to 1 through the singlet excited state occurred efficiently, whereas in polar acetonitrile the cleavage was reduced to half by solvation of the excited states. A photocleavage of dimers also occurred in their triplet states.
Structures of Diterpenoid Tropolones, Salviolone and Miltipolone, from the Root of Salvia miltiorrhiza Bunge
Authors: Haro Ginda , Mori Masahito , Ishitsuka Midori O , Kusumi Takenori , Inouye Yoshinobu , Kakisawa Hiroshi
Published: July 2006

New types of a bisnorditerpenoid and a norditerpenoid possessing a benzotropolonoid and a tropolonoid moieties, salviolone (8) and miltipolone (15), respectively, have been isolated and their structures were determined by spectroscopic methods. The structure of salviolone was confirmed by a total synthesis. These compounds exhibit cytotoxic activities against cultured cells.
Oxidation of 4,6,8-Trimethylazulene and Guaiazulene with Hydrogen Peroxide in Pyridine
Authors: Matsubara Yoshiharu , Morita Masanori , Takekuma Shin-ichi , Nakano Tomohiro , Yamamoto Hiroshi , Nozoe Tetsuo
Published: July 2006

Oxidation of 4,6,8-trimethylazulene (1) with hydrogen peroxide in pyridine at 25°C for 18 h gave 4,6,8-trimethyl-1,5- and -1,7-azulenequinones, their 2-(4,6,8-trimethyl-1-azulenyl) derivatives, and 2,3-dihydro-4,6- and -4,7-dimethyl-2-(4,6,8-trimethyl-1-azulenyl)-1H-inden-1-ones in much higher yields than those by autoxidation of 1 in DMF at 120°C. The same oxidation of guaiazulene afforded sixteen separable products, among which there were three new dimeric condensates.