bluuebunny/crossref_metadata_2025 huggingface dataset:
Studies of Reactions of Amines with Sulfur Trioxide. VI. Thermal Reactions of Anilinium, Dimethylanilinium, and Trimethylanilinium Salts of Butylamidosulfuric Acid
Authors: Kanetani Fujio , Yamaguchi Hachiro
Published: July 2006

When the title compounds were heated in an evacuated reaction vessel, both transsulfonation and rearrangement occurred. At lower temperatures (80–120 °C) the corresponding phenylamidosulfates and sulfophenylamidosulfates (transsulfonation products) were the main products. Increasing temperature led to the formation of ring mono- and disulfonates (rearrangement products) at the expense of the transsulfonation products. The sulfonate group always migrated to the ortho and/or para position(s) to the amino group. In no case was any meta-product detected. There was no significant difference in the ease of transsulfonation among the anilinium salts studied except 2,6-dimethyl- and 2,4,6-trimethylanilinium salts. On the other hand, the ease of rearrangement and the orientation of ring sulfonation depended strongly on the structure of the substrate anilines. The thermal reactions of 2,4,6-trimethylanilinium butylamidosulfate produced (2,4,6-trimethylphenylimido)bis(sulfate) in addition to (2,4,6-trimethylphenylamido)sulfate. This is the first isolation of an arylimidobis(sulfate) from such reactions. Mechanisms of the transsulfonation and the rearrangement have been discussed.
The Mechanism of the Reaction of (Aryloxy)trimethylstannane with Benzyl Bromide giving Aryl Benzyl Ether
Authors: Kozuka Seizi , Kikuchi Akihiko , Yamaguchi Shigeru
Published: July 2006

A kinetic study has been performed for the reaction of (aryloxy)trimethylstannane with benzyl bromide giving aryl benzyl ether and bromotrimethylstannane. Bimolecular nucleophilic attack of the aryloxy-oxygen on the benzyl-carbon has been suggested for the reaction based on the substituent effect.
The Binding of Sodium Dodecyl Sulfate to Lysozyme in Aqueous Solutions
Authors: Fukushima Kohsuke , Murata Yoshio , Nishikido Nagamune , Sugihara Gohsuke , Tanaka Mitsuru
Published: July 2006

The binding mode of sodium dodecyl sulfate to lysozyme and the accompanying structural change of lysozyme by binding have been investigated by means of the binding isotherm, the precipitation curve, and the CD spectra in pure water, NaCl, and borate buffer solutions. The precipitation phenomena could be explained in terms of the neutralization of the net charge of lysozyme due to dodecyl sulfate-ion binding. The analysis of the binding isotherms by the use of the BET equation gave the site number of the first layer corresponding to the positively charged residues at the pH studied. The conformational change from the β-structure to the α-helix has been observed in the second-layer binding. The environmental change of the side-chain residues has also been observed.
The Temperature Dependence of the Localization and Scavenging of Electrons in a Glassy 2-Methyltetrahydrofuran Matrix
Authors: Yoshizaki Masato , Ogasawara Masaaki , Yoshida Hiroshi
Published: July 2006

The nature and behavior of localized electrons in a γ-irradiated 2-methyltetrahydrofuran matrix were studied at 4 and 77 K by optical absorption measurements. Electrons localized in shallow traps generated at 4 K in a neat matrix showed one broad peak with εmax of 1.2×104 mol−1 dm3 cm−1 at 1490 nm. The yield was 1.9 (for 100 eV energy absorbed). This yield is less than the yield of electrons localized in deep traps at 77 K, 2.6. With an increasing concentration of biphenyl added to the matrix, the localized electrons were completely transformed into biphenyl anions. The scavenging efficiency was twice as high at 4 K as at 77 K. These results indicated that the electron scavenging took place by tunneling of the once localized electrons.
Selective Separation of Cr(VI) from Cr(III) in Seawater by Cobalt-1-pyrrolidinecarboditioate Coprecipitation Method
Authors: Fujiwara Kitao , Toda Shozo , Fuwa Keiichiro
Published: July 2006

Specific coprecipitation of Cr(VI) in artificial seawater with Co(II)–APDC complex was investigated. The maximum recovery by coprecipitation was 60.6±4.54% at pH 2 in which Cr(III) was completely separated from Cr(VI).
Potentiometric and Spectroscopic Investigations of the Reaction of Fluorescein Isothiocyanate with an Amine Chemically Bound on Solid Surfaces
Authors: Yamamoto Naoto , Nagasawa Yoshikatsu , Shuto Sadanobu , Tsubomura Hiroshi
Published: July 2006

Titanium electrode surface was chemically modified with an aminosilane. The potential of the electrode was shifted to the negative direction by a reaction of fluorescein isothiocyanate in solution with the amine on the electrode surface. The absorption and emission spectra were measured for the fluorescein isothiocyanate, fixed by the reaction with the aminosilane which was chemically bound on the surfaces of tin oxide, titanium oxide and quartz, in solutions and in air. In an alkaline solution, the absorption and emission spectra showed the band ascribable to the dianion of the fluorescein. A peak, attributable to the monoanion, was observed in both absorption and emission spectra measured for the samples kept in air. The surface coverage of the dye was estimated from the absorbances to be about 10−6 mol m−2 for both tin oxide and quartz. The bound dye fluoresced under exposure to ultraviolet light, due probably to the energy transfer from tin oxide to the dye.
The Disproportionation of Dimethyldialkoxysilanes Catalyzed by Iodine Monobromide
Authors: Ibaraki Takeshi , Ito Katsuko
Published: July 2006

Iodine monobromide is an extremely effective catalyst for the redistribution of alkoxyl groups on silicon atoms in dimethyldiakoxysilanes. The equilibrium constants of these reactions were determined at 40 °C by means of gas chromatography. Assuming that the reaction intermediate is the dative form of a dimethyldialkoxysilane–iodine monobromide complex, a mechanism of the reaction was proposed.
Mechanisms of Light-initiated Redox Reactions of Copper(II)–Cyclic Polyamine Surfactant Assemblies
Authors: Moroi Yoshikiyo
Published: July 2006

Photo-induced reduction of Cu2+ ion by organic electron donors was studied, main attention being paid to the decay kinetics of the cationized donor using two kinds of Cu2+ ions; one is free to move around the micellar surface of copper(II) dodecyl sulfate(Cu(DS)2), the other being fixed in a cyclic polyamine, Cu2+ complex of 2-tetradecyl-1,4,7,10-tetraazacyclododecane (CPA). Sodium 12-(10-phenothiazinyl)dodecanesulfonate (PTHDS) functions quite similarly to N-methylphenothiazine (MPTH) in an electron transfer reaction in Cu(DS)2 micelles, and the reduced Cu+ is ejected from the micelles. In the MPTH–CPA system, MPTH+ is completely ejected from the host micelle in the CPA micellar system. In consequence, the decay of the cationized donor obeys a second-order rate law, while the rate constant becomes much less. In PTHDS–CPA micellar system, on the other hand, the kinetics of the cationized donor is a superposition of two first-order decays of different rate constants, which suggests that the cationized donor can not escape into an intermicellar bulk phase due to the hydrophobic interaction between the long alkyl chain and its host micelle. A similar decay was also observed in the mixed micelles of the polyamine and hexadecyltrimethylammonium bromide.
Kinetic Studies of Fast Equilibrium by Means of High-performance Liquid Chromatography. III. Ternary Complex Formation between Ni(II) Diethyldithiocarbamate and Other Unlike Ni(II) Chelates
Authors: Moriyasu Masataka , Hashimoto Yohei
Published: July 2006

The labile ternary complex formation (MA2+MB2\ightleftharpoons2MAB with K=[MAB]2/([MA2][MB2])) between Ni(II) diethyldithiocarbamate(MA2) and other several Ni(II) chelates(MB2) was investigated by high-performance liquid chromatography; two solutions of MA2 and MB2 were mixed and equilibrated. The tendency to form a ternary complex is summarized as follows: (1) no ternary complex formation takes place (B=dimethylglyoxime and 1-(2-pyridylazo)-2-naphthol), for which high structural stability of binary complex MB2 is responsible; (2) the ternary complex formation is controlled statistically (K=4.0), suggesting the absence of any factor to stabilize or unstabilize the ternary complex (B=N,N-disubstituted dithiocarbamates and N-monosubstituted dithiocarbamates); (3) the ternary complex formation is favored (K>4.0) (B=xanthates); and (4) all initial binary complexes are converted into a very stable species which is possibly a ternary complex (B=dithizone). Kinetic characteristics of these ternary complex formations are examined.
Reactions of Bis(β-diketonato)palladium(II) and -platinum(II) with Tertiary Phosphines
Authors: Okeya Seichi , Nakamura Yukio , Kawaguchi Shinichi
Published: July 2006

Bis(β-diketonato)palladium(II) and -platinum(II) readily react with tertiary phosphines (L) to afford [M(β-dik)(β-dik-O)L], [M(β-dik)L2](β-dik), [ML4](β-dik)2, [M(β-dik-O)2L2], and [M(β-dik)(β-dik-C)L] complexes, which were characterized mainly by infrared and 1H and 13C NMR spectroscopy. Factors influencing the relative stability of each bonding mode of β-diketonate anions were investigated.
Synergistic Extraction of Vanadium(V, IV) with Dithizone
Authors: Akaiwa Hideo , Kawamoto Hiroshi , Hiyamuta Etsuo
Published: July 2006

By employing the synergistic extraction technique, vanadium (V,IV) has been found to form the primary dithizonate in the presence of a synergist. The extraction of the element proceeds according to the following equations.

VO2++H2dz,org+TBPOorg\ightleftharpoonsVO2(Hdz)(TBPO)Org+H+,

and

VOOH++H2dz,org\ightleftharpoonsTOPOorg\ightleftharpoonsVOOH(Hdz)(TOPO)org+H+,

where H2dz, TBPO, and TOPO denote dithizone, tributylphosphine oxide and trioctylphosphine oxide, respectively, and the subscript org indicates the benzene phase. The resulting adduct VO2(Hdz)(TBPO) has an absorption maximum at 503 nm and is stable for at least 1 h. However, the red color of VOOH(Hdz)(TOPO) in benzene fades away during the standing time, probably due to the dimerization of the initially extracted monomeric species.
Platinum Chloride–Diphosphine–Tin(II) Halide Systems as Active and Selective Hydroformylation Catalysts
Authors: Hayashi Teruyuki , Kawabata Yasuziro , Isoyama Toyoshiro , Ogata Ikuei
Published: July 2006

The hydroformylation of 1-alkenes was efficiently catalyzed by PtCl2–diphosphine–SnX2 systems whose diphosphines were 1,4-bis(diphenylphosphino)butane derivatives with rigid ring skeletons. The effects of the structure of diphosphines, the P/Pt atomic ratio, the sort of tin(II) halide or solvent, the reaction variables, and the structure of olefins on the relative rate and the product distribution were investigated. A higher reaction rate than when using HRh(CO)(PPh3)3, and a linearity of aldehydes up to 99%, were attained. The coordination structure of the effective diphosphines as well as the reasons for the rate enhancement and for the excellent selectivity were discussed.
The Rhodium Complex-catalyzed Synthesis of Quinolines from Aminoarenes and Aliphatic Aldehydes
Authors: Watanabe Yoshihisa , Shim Sang Chul , Mitsudo Take-aki
Published: July 2006

A variety of aminoarenes react with aliphatic aldehydes in the presence of a catalytic amount of a rhodium complex and an excess amount of the corresponding nitroarenes at 180 °C to give 2-alkyl- and 2,3-dialkyl-substituted quinolines in excellent yields. Among the rhodium complexes examined, [Rh(norbornadiene)Cl]2 exhibits the highest activity as a catalyst. Thus, 2-methyl-, 2-ethyl-3-methyl-, 2-propyl-3-ethyl-, and 2-butyl-3-propylquinoline derivatives are readily obtained from aminoarenes and ethanal, propanal, butanal, and pent-anal respectively.
Syntheses and Properties of α-Ethyl-substituted Bisdehydro[13]annulenone and Its Benzo-annelated Derivatives
Authors: Ojima J\={u}ro , Juni Yasushi , Yoneyama Yoshiharu , Wada Kazuyo , Murosawa Yoshiko
Published: July 2006

2-Ethyl-5,10-dimethyl-, 13-ethyl-10-methyl-4,5-benzo-, 2-ethyl-10-methyl-4,5-benzo-, and 2-ethyl-4,5:10,11-dibenzo-6,8-bisdehydro[13]annulenone were synthesized. Influence of α-ethyl substitution upon the skeleton of the bisdehydro[13]annulenone ring system is discussed on the basis of 1H NMR and UV spectra of these an-nulenones and their corresponding α-methyl-substituted derivatives.
Low-temperature Reflection Spectra of the Single Crystals of TCNQ Complex Salts
Authors: Yakushi Kyuya , Iguchi Masaaki , Katagiri Gen , Kusaka Takahisa , Ohta Toshiaki , Kuroda Haruo
Published: July 2006

The visible and near-infrared reflection spectra were measured, at temperatures in the range of 27–300 K, on the single crystals of (N-ethyl-1,10-phenanthrolinium)(TCNQ)2, (methyltriphenylphosphonium)(TCNQ)2 and Cs2(TCNQ)3. We found that the dispersion observed at about (10–11)×103 cm−1 in the reflection spectra of the former two salts is due to the local excitation associated with the lowest π-π transition of (TCNQ)−. A new dispersion attributable to intermolecular charge transfer was found to appear at (7–8)×103 cm−1 in the spectrum of (methyltriphenylphosphonium)(TCNQ)2, at low temperature. In the case of Cs2(TCNQ)3, the low-temperature spectrum showed that there are two dispersions in the range of (8–14)×103 cm−1, one of which being attributable to the charge transfer between (TCNQ)− ions and the other to the local excitation associated with (TCNQ)−. We propose a new interpretation for the spectra of TCNQ complex salts on the basis of these new experimental data.
Reduction by a Model of NAD(P)H. 33. Steric and Electronic Effects on Asymmetric Reduction of 2-Acylpyridines
Authors: Ohno Atsuyoshi , Nakai Jun-ichi , Nakamura Kaoru , Goto Takehiko , Oka Shinzaburo
Published: July 2006

Series of alkyl and fluorinated alkyl 2-pyridinyl ketones have been reduced by a chiral NAD(P)H-model (Me2PNPH) in the presence of magnesium ion in acetonitrile. Optical yield decreases in the order of substituent: CH3>C2H5>C(CH3)3>CH(CH3)2 and CH3>CH2F>CHF2>CF3. The results have been interpreted in terms of conformation of the substrates for alkyl 2-pyridinyl ketones and of electronic competitional effect between two substituents for fluorinated alkyl 2-pyridinyl ketones. Magnesium ion freezes intermolecular arrangement at the transition state of the reduction.
Reduction by a Model of NAD(P)H. 34. Substituent Effect on Asymmetric Reduction of Trifluoroacetophenones
Authors: Ohno Atsuyoshi , Nakai Jun-ichi , Nakamura Kaoru , Goto Takehiko , Oka Shinzaburo
Published: July 2006

Substituted and unsubstituted α,α,α-trifluoroacetophenones were reduced by a chiral NAD(P)H-model (RR-Me2PNPH). Both electron-releasing and -withdrawing substituents give better optical yields than unsubstitued compound. The result has been interpreted in terms of three-step mechanism which involves initial electron-transfer process.
Kinetic Studies on Intramolecular Excimer Formation in Dinaphthylalkanes
Authors: Ito Shinzaburo , Yamamoto Masahide , Nishijima Yasunori
Published: July 2006

Various dinaphthylalkanes in which two naphthyl groups are separated by three carbon atoms were prepared, and intramolecular excimer formation was investigated. All rate constants in Förster’s kinetics were determined by the steady state and time-resolved fluorescence measurements. A large difference in the association rate constant was observed with variation of molecular structure. The results suggest that intramolecular excimer formation is directly controlled by the rotational relaxation processes of the molecules from their neighboring conformations to the excimer conformation. A large formation rate (7.9×108 s−1 at 25 °C) was observed for meso-2,4-dinaphthylpentane, the rate for the racemo isomer being found to be one tenth of that for the meso isomer. This indicates that the isotactic sequence in vinyl aromatic polymers plays an important role in the intramolecular excimer formation.
Studies of Matrix Effects on 57Co-Labelled Tris(β-diketonato)cobalt(III) by Means of Mössbauer Spectroscopy
Authors: Sakai Yoichi , Endo Kazutoyo , Sano Hirotoshi
Published: July 2006

The emission Mössbauer spectra at 78 K of 57Co-labelled Co(dbm)3 (dbm=dibenzoylmethanato) dispersed in 2-methyltetrahydrofuran, or of 57Co-labelled Co(acac)3 (acac=acetylacetonato) dispersed in a mixed medium of oxalic acid and polystyrene, give no appreciable magnetic hyperfine structure (hfs), while those of 57Co-labelled Co(acac)3 dispersed in polystyrene and 57Co-labelled crystalline Co(dbm)3 give a magnetic hfs. The results indicate that the local radiolysis of EC-decay involves not only the labelled species itself, but also the neighbouring host matrix.
Some Aspects of the Solvent Extraction-spectrophotometric Determination of Copper Dithiocarbamate Complex in Strongly Acidic Media
Authors: Takada Takeo , Okabe Yukio , Nakano Kunio
Published: July 2006

The time stability of the extracted complexes in isobutyl methyl ketone depends on the pH of the washing solution of the extract and on the stability of the metal complex. The extract is stable to concentrated acid when the organic extract is separated rapidly and washed with water. Copper (II) tetramethylenedithiocarbamate is quantitatively extracted from 1–6 and 1–2 mol dm−3 hydrochloric and nitric acid media respectively.
The Preparation and Properties of Cobalt(III) Phosphine Complexes Containing Nitrite and Acetylacetonate Ions
Authors: Hayakawa Satoru , Nishikawa Hiroaki , Kashiwabara Kazuo , Shibata Muraji
Published: July 2006

Two complexes, [Co(NO2)(acac)2(P)](acac=acetylacetonate ion, P=PBu3, PBu2Ph, PMe2Ph, and PMePh2) and [Co(NO2)2(acac)(PMe2Ph)2], were prepared by a reaction between Na[Co(NO2)2(acac)2] and phosphines. The geometrical structures were determined on the basis of the 1H NMR, electronic, and IR spectra. A cis(NO2,P) configuration was assigned to [Co(NO2)(acac)2(P)], and a trans(P,P) configuration, to [Co(NO2)2(acac)(P)2].
Theory of Molecular Deformation Due to the Vibronic Interaction between Two Closely-spaced Electronic Levels. I
Authors: Kimura Minoru , Nishikawa Kiyoshi , Aono Shigeyuki
Published: July 2006

An theoretical investigation was made of the vibronic interaction between two electronic levels which are degenerate or nearly degenerate. Within the mean field approximation we derive a simplified effective Hamiltonian to analyze the problem of bond distortion of a molecule; the effective Hamiltonian is diagonalized by a linear canonical transformation of electronic operators. Thermodynamic arguments predict a possibility for appearance of a distorted phase below a characteristic temperature. The distorted phase is realized under a sufficiently strong coupling condition in a non-degenerate case, but under an arbitrarily small coupling condition in a degenerate case. The shift of electronic spectrum, the stabilization energy of the distortion, and thermodynamic quantities are expressed in terms of the parameters associated with the Hamiltonian. Change in electromagnetic properties due to the distortion is discussed. Magnitudes of the bond distortion and energy stabilization in the ground state are numerically estimated for cyclobutadiene, with results in good agreement with literature values.
Redetermination of the Crystal Structure and the Electrical Resistivity of Rb–TCNQ-II
Authors: Kobayashi Hayao
Published: July 2006

The crystal structure of Rb–TCNQ-II was redetermined. The interplanar distance between the neighbouring TCNQ’s is 3.25 Å, which is almost equal to those of highly conducting TCNQ salts. The electrical resistivity and the structure of the TCNQ, columns suggest that the complete charge transfer in Rb–TCNQ-II makes this crystal low-conducting. The activation energy of the electrical conduction indicates that the dimerization gap appears below the monomer-dimer transition temperature. The temperature dependence of the electrical resistivities of Rb2TCNQ3 is also described.
Catalytic Activity of Highly Dispersed Palladium. II. X-Ray Photoelectron Spectroscopic and Thermal Desorption Studies of the Effects of ZrO2 Added to α-Alumina-supported Palladium
Authors: Lee Bu Yong , Inoue Yasunobu , Yasumori Iwao
Published: July 2006

The effects of ZrO2 upon the catalytic properties of α-alumina-supported palladium for the hydrogenation of gaseous cyclohexene were studied by means of detailed kinetic analysis, thermal desorption (TD), and X-ray photoelectron spectroscopy (XPS). The catalysts, with ZrO2 added in amounts ranging from 0.1 to 45 in Zr/Pd ratio, were characterized by CO chemisorption and X-ray diffraction. The addition of ZrO2 at the Zr/Pd ratio of 0.5 enhanced the turn-over frequency of the hydrogenation by a factor of 7 and changed the hydrogen order of the reaction from 1.0 to 0.75 and the cyclohexene order from 0 to 0.6. The reaction with D2 exhibited deuteriumdistribution patterns similar to those for the reaction on the ZrO2-supported Pd catalysts. The hydrogenation pathway on the ZrO2-added catalyst was described by an associative mechanism in which the slow step was a surface reaction between a cyclohexyl radical and a hydrogen atom. In the thermal desorption spectra, the addition of ZrO2 caused a broadening of the adsorbed hydrogen peak as well as a shift of the dissolved hydrogen peak toward a lower temperature. The desorption of cyclohexene from Pd/α-Al2O3 catalysts underwent a disproportionation to produce benzene around 318 K and cyclohexane at 368 K, whereas the latter peak shifted by 70 K to the lowertemperature side upon the addition of ZrO2. The XPS study showed that the presence of ZrO2 provided Pd metal atoms in a negatively-charged state. The support effect was discussed on the basis of the interaction between Pd metal atoms and ZrO2 oxide.
Mössbauer Spectroscopic Study of Potassium Borosilicate Glasses at Low Temperatures
Authors: Nishida Tetsuaki , Hirai Toshiharu , Takashima Yoshimasa
Published: July 2006

The Mössbauer technique at the liquid nitrogen temperature (78 K) was applied to the estimation of nonbridging oxygens in FeO4, BO4, and SiO4 units in potassium borosilicate glasses. Mössbauer spectra consist of a quadrupole doublet and a hyperfine structure due to Fe3+ ions with tetrahedral symmetry. The hyperfine structure is attributed to a relaxation effect because magnetic susceptibility measurements revealed the glasses to be paramagnetic in the temperature range 78–295 K. A linear decrease in the absorption area and a similar decrease in the internal magnetic field for the hyperfine structure were observed with an increase in the alkali content of glasses. The decrease is ascribed to a formation of non-bridging oxygen at the site adjacent to iron, because the mean life-time of the internal magnetic field produced by 3d-electrons of iron is considered to decrease with increasing thermal vibration of the iron and neighboring oxygens. Fractions of non-bridging oxygens obtained from the reduction rate of the absorption area of hyperfine structure are in good agreement with earlier results for borate glasses with the same K2O/B2O3 ratios, in the alkali region of 8–20 mol% where the borosilicate glasses are essentially considered to be borate glasses diluted with SiO2.
Kinetics of Ligand Substitution Reactions in Trimalonatoyanadium(III)
Authors: Ikeda Yasuhisa , Soya Sumio , Tomiyasu Hiroshi , Fukutomi Hiroshi
Published: July 2006

The kinetics of ligand substitution reactions in trimalonatovanadium(III), V(mal)33−, with various multidentate ligands, malonate (MAL), ethylenediaminetetraacetate (EDTA), and nitrilotriacetate (NTA) have been studied. The rate constant of the malonate exchange in V(mal)33− was obtained from the NMR line-broadening method to be kex=50 s−1 at 70 °C. The rate of EDTA substitution depends on the entering EDTA species. The values of second order rate constants are k21=0.04 M−1 s−1 (1 M=l mol dm−3) for H2edta as an entering ligand and k22=0.25 M−1 s−1 for H3edta at 25 °C. The NTA substitution is reversible under the experimental conditions studied. The apparent rate constants of the forward and backward reactions are k3=1.3×10−2 M−1 s−1 and k−3=2.0×103 M−1 s−1 at pH 3.5 and 25 °C, respectively. The univalent H2nta is found to be the only entering ligand.
Ternary α-Amino Acid-Palladium(II) Complexes with Ligand-Ligand Hydrogen Bonding
Authors: Odani Akira , Yamauchi Osamu
Published: July 2006

Histidinate(His)-containing ternary α-amino acid-palladium(II) complexes have been studied by synthetic and spectroscopic methods. The following complexes with imidazolate (im), l- and d-His, l-asparaginate (l-Asn), and l-glutaminate (l-Gln) have been isolated as crystals: [Pd(im)2]·0.5H2O; [Pd(l-His) (d-His)]·H2O; [Pd(l-Asn)-(l-His)]·2H2O; [Pd(l-Gln) (l-His)]·2H2O. The ternary systems involving palladium (II), l-His, and an amino acid l-AA with an OH or a CONH2 group (AA=Asn, Gln, serinate, threoninate, or homoserinate) exhibit absorption maxima at 300–311 nm with ε 310–440 and negative and positive circular dichroism (CD) peaks at 307–328 nm and ≈300 nm, respectively. 13C and 1H NMR spectra gave the amounts of the cis and trans isomers of Pd(His)-(AA) in solution and confirmed that Pd(His)(AA) has an N3O donor set in the coordination plane. Whereas the CD magnitude additivity holds for the ternary systems Pd (l-His)(B) with B=glycinate, l-alaninate, or l-valinate and the systems with l-histidine methyl ester (l-HisOMe) and l-AA, Pd(l-HisOMe)(l-AA), the magnitudes for Pd (l-His) (l-AA) deviate significantly from those estimated on the basis of the additivity. The CD magnitude anomaly as well as the geometrical and rotational isomer populations calculated from the 1H NMR spectra establishes the existence of the ligand-ligand interaction between the carboxylato group of His and the hydroxyl or amido group of AA in solution.
Synthesis and Properties of S,S-Diaryl Thymidine Phosphorodithioates
Authors: Sekine Mitsuo , Hamaoki Ken , Hata Tsujiaki
Published: July 2006

Appropriately protected or unprotected S,S-diphenyl thymidine 3′- or 5′-phosphorodithioates and S,S-bis(4-methoxyphenyl) thymidine 3′- or 5′-phosphorodithioates were successfully prepared by the reaction of the thymidine derivatives with cyclohexylammonium S,S-diaryl phosphorodithioates in the presence of 2,4,6-triisopropylbenzene-sulfonyl chloride (TPS). Stabilities of the thymidylic compounds under acidic or alkaline conditions were described in detail. Several methods for the deprotection of one or both arylthio groups under neutral conditions were also described in connection with the synthesis of oligothymidylates. By the use of the bis(4-methoxyphenylthio)phosphoryl group, di- and tri-thymidylates were synthesized in high yields.
14N Nuclear Quadrupole Resonance of the Molecular Complexes of Urea
Authors: Negita Hisao , Kubo Tsuneo , Kato Hitoshi
Published: July 2006

The 14N nuclear quadrupole resonance (NQR) was studied in four kinds of molecular complexes of urea, such as urea-nitric acid, urea-phosphoric acid, urea-oxalic acid, and urea-ammonium chloride. The 14N quadrupole coupling constants and asymmetry parameters at liquid nitrogen temperature are as follows: |e2Qq⁄h|=3.157 MHz and η=0.475 for the HNO3 complex; |e2Qq⁄h|=3.277 MHz and η=0.414 for the H3PO4 complex; |e2Qq⁄h|=3.456 MHz and η=0.363 for the (COOH)2 complex; and |e2Qq⁄h|=3.544 MHz and η=0.298 for the NH4Cl complex. From the temperature dependence of the resonance lines in these complexes, the strength of hydrogen bonds are discussed. The differences of the electron densities at the nitrogen atoms between urea and its complexes were derived from the corresponding NQR parameters, and the bond characters in these complexes are discussed.
Studies on Mixed Chelates. XI. Syntheses and Comparative Study of a New Series of Mixed Nickel(II) Chelates with Halide and Pseudohalide Ligands
Authors: Hoshino Naomi , Fukuda Yutaka , Sone Kozo
Published: July 2006

A new series of mixed chelates of nickel(II), Ni(diam) (β-dik)X·nH2O (X= halide or pseudohalide anion, n=0–2), was prepared, and their structures in solid state and in various organic solvents were studied. Most of the chelates were octahedral, many of them being obtained as mono- or dihydrates. When the solid chelates were heated at reduced pressure, the main reactions were dimerization (X=pseudohalide), dehydration (X=I), and disproportionation (X=Br or Cl). On the other hand, the chelates showed complicated structural changes in organic solvents, some of which were not observed in solids, depending upon the nature of X and the polar characteristics of the solvent.
Transition-metal Complexes of Pyrrole Pigments. XIX. Electrochemical and Coordination Behaviors of (5,10,15,20-Tetraphenyl porphinato)niobium(V) Complexes
Authors: Matsuda Yoshihisa , Yamada Sunao , Goto Takashi , Murakami Yukito
Published: July 2006

The redox chemistry of acetato(5,10,15,20-tetraphenylporphinato)oxoniobium(V) (1) was investigated in dichloromethane by means of cyclic voltammetry and controlled potential electrolysis. One-electron reduction potentials were observed at −0.89, −1.05, and −1.41 V vs. SCE for the range from 0 to −2.0 V; the reduction of niobium(V) to niobium(III) occurred prior to ligand-reduction. The potential separation between first and second metal-reductions (ΔE1⁄2) for 1 is 0.16 V, while ΔE1⁄2 between reductions of the MoVI and MoV species for the corresponding molybdenum complex is 1.24 V. In order to elucidate the origin of such potential difference between the niobium and molybdenum complexes, the change of coordination structures which takes place in the course of redox reactions was examined. The coordination reaction of 1 with pyridine was also studied.
Restricted Rotation Involving the Tetrahedral Carbon. XXXVI. Stereodynamics of 9-(2-MethylbenzyI)triptycene Derivatives
Authors: Yamamoto Gaku , Oki Michinori
Published: July 2006

DNMR study of a series of singly peri-substituted 9-(2-methylbenzyl)triptycene derivatives showed that the interconversion among the ap and ±sc rotamers with the o-methyl group pointing outside the triptycyl skeleton occurs by two consecutive gear motion steps by way of the unstable rotamers with the o-methyl group pointing inside. The+sc\ightleftharpoons−sc interconversion barriers (13.2—14.1 kcal/mol) are lower than the ap\ightleftharpoons±sc ones (17.7–20.8 kcal/ mol). The aryl group passes over a peri-hydrogen at the transition state of the former process and over the peri-substituent in the latter.
Chiral and Stereoselective Total Synthesis of (−)-Deoxoprosopinine and (−)-Deoxoprosophylline. Intramolecular Amino mercuration of an ε,ζ-Unsaturated Amine
Authors: Saitoh Yutaka , Moriyama Yoshihiko , Hirota Hiroshi , Takahashi Takeyoshi , Khuong-Huu Qui
Published: July 2006

l-Serine was transformed in 8 steps into (4R,5S)-2,2-dimethyl-4-[(Z)-3-pentadecenyl]-1,3-dioxan-5-amine. This chiral ε,ζ-unsaturated amine was subjected to intramolecular aminomercuration and then acid hydrolysis to give (−)-deoxoprosopinine and (−)-deoxoprosophylline.
Induced Circular Dichroism of β-Cyclodextrin Complexes with o−, m−, and p-Disubstituted Benzenes
Authors: Shimizu Hiroshi , Kaito Akira , Hatano Masahiro
Published: July 2006

The induced circular dichroism (ICD) spectra of β-cyclodextrin (β-CDx) complexes with o−, m−, and p-disubstituted benzenes were observed. The comparison of the observed rotational strengths with the ones calculated by using the Kirkwood-Tinoco expression is examined; the possible orientations of the guest molecules which are included in the cavity of β-CDx are presented. These results suggest that the orientation of the guest molecule is confined about the axis of the β-CDx torus.
The Reactions of NH Radicals with Ethylene and Propene in the Liquid Phase
Authors: Kitamura Takashi , Tsunashima Shigeru , Sato Shin
Published: July 2006

The photolysis of hydrogen azide was studied in liquid ethylene, propene, and the mixture with ethane at the temperature of Dry Ice–methanol. The products observed were aziridine (0.18), ammonia (0.16), and nitrogen (1.0) from the ethylene solution and 2-methylaziridine (0.33), allylamine (0.12), ammonia (0.17), and nitrogen (1.0) from the propene solution. The values in parentheses show the yields relative to that of nitrogen. The relative yields were independent of the concentration of hydrogen azide in the range of 0.8–8×10−2 mol dm−3. The reaction of NH(a1Δ) radicals with olefin consists of three processes: the addition to double bond, the insertion into the C–H bond, and the deactivation to the 3Σ− state. The branching ratios and the relative rate constants of the reactions of NH(a1Δ) radicals with ethylene, propene, and ethane were estimated.
The Stereoselective Deacylation of Long-chain Amino Acid Esters by Comicelles of N-Acyl-l-histidine and Various Cationic Surfactants
Authors: Ohkubo Katsutoshi , Sugahara Kiyoshi , Ohta Hidefumi , Tokuda Katsuro , Ueoka Ryuichi
Published: July 2006

The stereoselective deacylation of H–(CH2)\undersetn−1—CONHCH(R)CO2–C6H4NO2-p (R=CH3, CH(CH3)2, CH2CH(CH3)2, and C6H5CH2; n=2–16) with N-acyl-l-histidine (acyl=octanoyl, dodecanoyl, and hexadecanoyl) and cationic surfactants (CmH2m+1\overset+N(CH3)2R X; (R,X,m)=(CH3,Br,16), (C2H5,Br,16), (C6H5CH2,Cl,16), and (\overset*CH(CH3)C6H5,Br, 14–18) was examined with particular reference to the structural effects of surfactants, nucleophiles, and substrates on both the deacylation rates and the stereoselectivity. The cationic surfactant, R-(+)-C16H33\overset+N(CH3)2\overset*CH(CH3)C6H5 Br, which possesses the hydrophobic and chiral groups near the polar head, formed the stereoselectively most effective comicelles with N-dodecanoyl-l-histidine. The order of stereoselectivity observed in the deacylation of the amino acid esters including the identical acyl chain length (n), phenylalanine>leucine>alanine∼valine. suggested steric effects of the substituent bound to the asymmetric carbon atom of the substrate on the stereoselectivity. The highest stereoselectivity (enantiomer rate ratio=4.4 at 25 °C under pH 7.61) was observed in the deacylation of the N-decanoylphenylalanine p-nitrophenyl ester, involving an appropriately long acyl chain.
Oxidation of Steroidal π-Allyl Palladium Chloride Complexes Using Chromium(VI) Oxide in N,N-Dimethylformamide
Authors: Satoh J Yasuo , Horiuchi C Akira
Published: July 2006

The oxidation of steroidal π-allyl palladium chloride complexes with the mild oxidizing agent composed of chromium(VI) oxide in N,N-dimethylformamide containing ether to dissolve the complex and a trace of sulfuric acid, afforded efficiently the corresponding α,β-unsaturated ketones.
Palladium Catalyzed Cyanocarbonylation of Organic Iodides
Authors: Tanaka Masato
Published: July 2006

Palladium complex catalyzed carbonylation of aromatic and heteroaromatic iodides in the presence of potassium cyanide gave aroyl cyanides in fair to excellent yields, offering the first example of cyanocarbonylation.
A Solid-state Electrochemical Study on the Phenothiazine–Iodine and Related Complexes
Authors: Matsumoto Toshiyuki , Matsunaga Yoshio
Published: July 2006

The electromotive force (emf) of a solid-state galvanic cell, Ag|AgI|PT–In, where PT–In is the phenothiazine-iodine complex, was examined as functions of the composition, n, and also of the temperature. Below n=2.5, a value of 616 mV was obtained at 25 °C. The emf increases stepwise to 620 mV at n=2.5 in conformity with the formation of a complex cation radical pentaiodide, as established by our earlier work. A continuous increase up to 649 mV was found before n=3, indicating the appearance of a nonstoichiometric phase covering the range from n=2.8 to 3. The upper limit of the existence region exactly corresponds with the minimum in the resistivity-composition isotherm. Similar studies with benzo[a]- and benzo[c]phenothiazines revealed the formation of three or four distinct nonstoichiometric complexes in each system. The Gibbs energy, enthalpy, and entropy of cell reactions and complex formation reactions are presented. The stability of the iodine complexes was found in the following order: benzo[a]phenothiazine>benzo[c]phenothiazine>phenothiazine.
The Crystal and Molecular Structure of Grayanotoxin XVIII. A New Minor Diterpene from Leucothoe Grayana Max.
Authors: Furusaki Akio , Gasa Shinsei , Ikeda Ry\={u}z\={o} , Matsumoto Takeshi , Yasuoka Noritake , Matsuura Yoshiki
Published: July 2006

The molecular structure of grayanotoxin XVIII C20H28O4, has been determined by means of X-ray crystal analysis. The crystals are monoclinic, with two molecules in a unit cell with dimensions of a=9.592, b=11.414, c=8.180 Å, and β=93.21°; the space group is P21. 1484 unique intensity data were collected on a four-circle diffractometer with Ni-filtered Cu Kα radiation. The structure was solved by the Monte Carlo direct method, using the 20 strongest reflections as the starting set; the 25th random-phase set led to the correct solution. The R value reached 4.6% by block-diagonal least-squares refinements. The structure thus obtained corresponds to 3-dehydrograyanotoxin VII. The C-ring takes a boat conformation. The force-field calculations suggest that this energy loss is probably compensated for by the stabilization of the B-ring conformation. The crystal consists of hydrogen-bonded molecular layers parallel to the (100) plane.
Reaction of Metastable Ar Atoms with Propylene in Flow System
Authors: Sibata Akiko , Takahasi Makoto , Ohno Shinichi , Mikuni Hitoshi
Published: July 2006

The reaction of metastable Ar atoms with propylene was studied in a discharge flow system. The major product is ethylene, although ethane, propane and butadiene are also identified as minor products. Within a limited range of propylene concentration the yield of ethylene is proportional to the concentration of propylene. Competitive quenching methods using mixtures of propylene and N2O or CO2 provided a rate constant of (8.4±0.3)×10−10 cm3 molecule−1 s−1 for the reaction of metastable Ar atom with propylene to yield ethylene. The assumption of a radical mechanism for the main reaction is consistent with the results of competitive quenching, radical scavenger and spin trapping experiments. Measurements of ion current in the reaction mixtures allow an estimation that ionic species contribute less than 2% to the reaction path leading to the formation of ethylene. The metastable Ar atom reaction was also compared to the direct and mercury-sensitized photolysis of propylene.
Absorption, Circular Dichroism, and Nuclear Magnetic Resonance Studies of Bis(acetylacetonato)cobalt(III) Complexes Containing 2-Aminoalkylphosphine Chelates with Phosphorus and Nitrogen Donor Atoms
Authors: Kashiwabara Kazuo , Kinoshita Isamu , Ito Tasuku , Fujita Junnosuke
Published: July 2006

Bis(acetylacetonato)cobalt(III) complexes containing a variety of 2-aminoalkylphosphines, NH2CH2CH2P(C6H5)2, (CH3)2NCH2CH2P(C6H5)2, (S)-NH2CH(CH3)CH2P(C6H5)2, rac-NH2CH2CH2P(CH3) (C6H5), (R)-NH2CH2CH2P(C4H9)(C6H5), and NH2CH2CH2P(CH3)2, and a diphosphine, (C6H5)2PCH2CH2P(C6H5)2 were prepared and resolved (or separated) into optical isomers by SP-Sephadex column chromatography. Absorption, circular dichroism, and 1H and 13C NMR spectra of the new complexes were measured and the results compared with those of the related complexes. Positions of the 2-aminoalkylphosphine and the related ligands in the spectrochemical series were as follows; CN−>NH2CH2CH2P(CH3)2>(C6H5)2PCH2CH2P(C6H5)2>NH2CH2CH2P(CH3) (C6H5)(Remark: Graphics omitted.)NH2CH2CH2P(C4H9)(C6H5)>NH2CH(CH3)CH2P(C6H5)2(Remark: Graphics omitted.)NH2CH2CH2P(C6H5)2(Remark: Graphics omitted.)NH2CH2CH2NH2>(CH3)2NCH2CH2P(C6H5)2. For the 13C NMR spectra, all the signals including those due to two diastereotopic phenyl groups on a phosphorus atom were assigned, and the chemical shifts and the coupling constants were determined. The methyl and carbonyl carbons which are trans to a phosphorus atom give a doublet signal due to four-bond (4J(C,P)=6–7 Hz) and three-bond (3J(C,P)=2–3 Hz) couplings, respectively, through a cobalt(III) ion.
Transformation of Dihydrostreptomycin into 3″-Deoxydihydrostreptomycin
Authors: Usui Takayuki , Tsuchiya Tsutomu , Umezawa Hamao , Umezawa Sumio
Published: July 2006

3″-Deoxydihydrostreptomycin active against resistant bacteria was prepared from dihydrostreptomycin (DHSM). The key intermediate in this synthesis is a protected derivative of DHSM in which all hydroxyl groups except the 3″-hydroxyl group are protected, namely, 2″-N-(benzyloxycarbonyl)-2,5,6-tris(O-tetrahydropyran-2-yl)-3′,3a′:4″,6″-bis(O-p-methylbenzylidene)-1,3-di-NG-tosyldihydrostreptomycin. 3″-Deoxygenation was successfully performed by 3″-O-imidazolylthiocarbonylation followed by treatment with tributylstannane. The Δ[M]TACu value of the synthetic 3″-deoxydihydrostreptomycin supports the structure.
The Oligomerization and Co-oligomerization of Active Methylene Compounds and Isocyanides Catalyzed by Octaisocyanidedicobalt
Authors: Yamamoto Yasuhiro , Yamazaki Hiroshi
Published: July 2006

The reactions of RNC with CH2R1R1(R=2,6-Me2C6H3; R1, R2=COOMe, COOEt, CN) in the presence of Co2(RNC)8 or Co2(CO)8 gave cyclic compounds in a 4:1 molar ratio. Co2(RNC)8 also catalyzed CH2(CN)2 to give a pyridine derivative.
Polarized Absorption Spectra of Indole and Benzimidazole
Authors: Maki Izumi , Nishimoto Kichisuke , Sugiyama Masa-aki , Hiratsuka Hiroshi , Tanizaki Yoshie
Published: July 2006

The polarization spectra of indole, 3-indolebutyric acid, and benzimidazole have been measured and analyzed by means of MO theory taking Σ-II interaction into consideration. Induced transition moment due to Σ-II interaction can be assigned to each σ-bond (both direction and magnitude) pictorially. The effect of hetero atom on the electronic absorption spectra can be interpreted reasonably. Agreement between experimental and calculated results is satisfactory.
Carbon-13 NMR Study on the Cyclodextrin Inclusion Complexes in Solution
Authors: Komiyama Makoto , Hirai Hidefumi
Published: July 2006

A correlation between the penetration depth of the carbon atoms of 4-nitrophenolate, benzoic acid, 4-nitrophenol and 2,6-dimethyl-4-nitrophenolate in the cavity of α-cyclodextrin and the changes of their 13C-chemical shifts has been investigated. By use of this relationship and the observed changes of the 13C-chemical shifts of 3-nitrophenol on the complex formation with α-cyclodextrin, the time-averaged conformation of the α-cyclodextrin-3-nitrophenol complex is determined.
Kinetic Studies of the Interaction of Bromphenol Blue with Bovine Serum Albumin by Pressure-jump Method
Authors: Murakami Kiyofumi , Sano Takayuki , Yasunaga Tatsuya
Published: July 2006

The interaction of Bromphenol Blue (BPB) with bovine serum albumin (BSA) was studied statically, by spectrophotometry, and kinetically, by the pressure-jump method. The absorbance changes of BPB were monitored at 20 °C, pH 7.00 in 0.2 M phosphate buffer. The static measurements showed that there were two binding classes. The number of binding sites and the binding constants for each class are n1=1, K1=1.4×107 M−1 and n2=3, K2=9.5×104 M−1. Kinetically, the binding of BPB to the primary binding site of BSA proceeds via at least 4 steps. Two models are offered for the possible binding mechanism. In these models, a fast, probably diffusion controlled, second order step is followed by three first order steps. A correlation between the number of binding steps and the magnitude of the binding constant is discussed. The positive activation entropies associated with the backward reactions of the second and third steps show that these reactions proceed through disordered activation states. From the comparison of the present results to those for other ligands, it was found that the ligand is intimately involved in which activated configuration is adopted.
Dehydration Associated with High-spin to Low-spin Conversion of 5,5,7,12,12,14-Hexamethyl-1,4,8,11-tetraazacyclotetradecane-nickel(II) Halide Dihydrate
Authors: Ito Tasuku , Tsutsumi Yukie , Hiratsuka Yukio , Mochizuki Katsura , Fujimoto Masatoshi
Published: July 2006

The title compounds, orange, diamagnetic four-coordinate complexes, [NiL]X2·2H2O (X=Cl, Br, I for meso-L, and X=Cl, Br for rac-L) were converted, upon dehydration by heating in the solid state, to violet, paramagnetic six-coordinate complexes, [NiX2L]. The enthalpies of the dehydration reactions were close to those for many simple inorganic hydrates and that for the ice–water vapor equilibrium in spite of the presence of the large organic ligand.
Conversion of Quassin into 15β-[(E)-3,4-dimethyl-2-pentenoyloxy]quassin. A D-Ring Analog of Bruceantin
Authors: Murae Tatsushi , Takahashi Takeyoshi
Published: July 2006

Quassin was transformed in five steps into 15β-[(E)-3,4-dimethyl-2-pentenoyloxy]quassin.
A Simple Method for the Synthesis of Exaltolide
Authors: Sato Toshio , Kawara Tatsuo , Kokubu Yasuchika , Fujisawa Tamotsu
Published: July 2006

Copper-catalyzed reaction of β-propiolactone with 12-methoxydodecylmagnesium bromide, derived from 1,12-dodecanediol, gives 15-methoxypentadecanoic acid in a high yield, which is easily converted into exaltolide.
A Magnetic Resonance Study of the Fe2O3/Al2O3 Catalyst in a CO–N2O Reaction
Authors: Niwa Miki , Yagi Kunihiko , Murakami Yuichi
Published: July 2006

A magnetic resonance study was performed in order to determine the phase of iron oxide supported on Al2O3 and to measure in situ the surface conditions during the reaction. The irreversible transition of α-Fe2O3 into Fe3O4 by the reduction of the supported catalyst and the reversible transition between Fe3O4 and γ-Fe2O3 were confirmed at 280 °C. The spectrum appearing at g=2.03 and having the line width of about 1000 gauss clearly showed ferrimagnetic behavior; it could be attributed to the ferrimagnetic resonance (FMR) of Fe3O4 and/or γ-Fe2O3. Kinetic study suggested that the CO–N2O reaction took place in the oxidation-reduction mechanism. The concentration of γ-Fe2O3 was calculated from not only the kinetic equation, but also the in situ measurement of the FMR signal; these values were consistent. The γ-Fe2O3/Al2O3 had nearly the same activity as the α-Fe2O3/Al2O3, whereas the unsupported γ-Fe2O3 had a lower activity than the α-Fe2O3. Such a difference in catalytic activity was discussed in comparison with other oxidation reactions.
Effect of Nucleophiles on the Rates of Dissociation and Racemization of the Tris(1,10-phenanthroline)iron(II) Ion in Aqueous Solutions
Authors: Tachiyashiki Satoshi , Yamatera Hideo
Published: July 2006

The rates of dissociation and racemization of the tris(1,10-phenanthroline)iron(II) ion were obtained in aqueous solutions containing fourteen kinds of nucleophile. They ranged from 0.7 to 9.3 and from 0.9 to 3.2 times the rates in pure water, respectively. The results were analyzed by considering simultaneous reactions of free and ion-paired complex ions. The rate constants of the dissociation (ligand release) of the complex existing in ion-pairs increased in the following order of the counter-ions: I−<Br−<Cl−<(H2O)<NO2−<CH3COO−<OCN−<N3−<F−<OH−≈CN−; here H2O is regarded as a nucleophile for the free complex ion. This order is similar to that of proton affinities of nucleophiles. The results show that the dissociation is accelerated by σ donation from the nucleophile, suggesting an ion-pair interchange mechanism. The intramolecular racemization rate constant, given by total recemization rate constant minus dissociation rate constant, increased in the following order of nucleophiles: OH−≈CN−≈F−≈Cl−<Br−≈NO2−<(H2O)<CH3COO−<OCN−<I−<N3−<(thiourea)≈SCN−≈SeCN−<(pyridine). This suggests that the polarizability of nucleophiles has a greater effect than their basicity. The operation of π interaction between the complex ion and the nucleophile in the transition state is also suggested. The ion-association constants obtained from the rate data were in the range of 1 to 8 (I=1.0, 32.0 °C).