bluuebunny/crossref_metadata_2025 huggingface dataset:
Mass-spectral Isotope Effects in the Metastable Transition of Benzene and Perdeuterio Benzene. Model Calculation
Authors: Arakawa Ryuichi , Yoshikawa Yozaburo
Published: July 2006

The abundances of C6H5+, C6H4+·, C4X4+·, and C3X3+ (X=H, D) fragments occurring in the metastable transition of benzene and perdeuterio benzene have been measured by means of electron-impact ionization. The isotope effects on the relative intensities were reproduced by the simple model calculation on the basis of the RRKM theory. The vibrational frequencies of the transition states for the deuteriated and the nondeuteriated were obtained by a vibrational analysis for the assumed geometries and force fields. The transition states for the C6H5+ and C6H4+· channels preferred a benzene structure while those for the C4H4+· and C3H3+ has a propargylcyclopropene structure. The calculated decay rates for the C6H5+, C4H4+· and C3H3+ fragmentation were compared with those of the photoion photoelectron coincidence (PIPECO) results.
Palladium(II) Complexes Containing Both the Chelating β-Diketonato and σ-Pyridyl Ligands. Catalyzed Coordination-site Exchange Reactions
Authors: Tanaka Hiroshi , Isobe Kiyoshi , Kawaguchi Shinichi , Okeya Seichi
Published: July 2006

A novel type of palladium(II) complexes, [Pd(β-dik)(pyridyl)(PPh3)] and [Pd(β-dik)(pyridyl)]2 containing a chelating acetylacetonate, trifluoroacetylacetonate, or hexafluoroacetylacetonate anion and 2-, 3-, or 4-pyridyl radical as the coexisting ligands were prepared and characterized by elemental analysis and molecular weight determination as well as 1H and 13C NMR spectroscopy. [Pd(acac)(C5H3(6-Cl)N–C2)(PPh3)] is stereochemically rigid in solution but undergoes the coordination-site exchange reaction catalyzed by nitrogen and phosphorus bases and donor solvents. Similar reaction of [Pd(acac)(C5H4N–C2)(PPh3)] is catalyzed by triphenylphosphine liberated by the dinuclear-complex formation reaction (autocatalysis). Intact molecules of [Pd(acac)(C5H4N–C3 and –C4) (PPh3)] catalyze mutually their own coordination-site exchange (self-catalysis).
The Preparation and Properties of Ethylenediamine(2-methyl-8-quinolinolato)cobalt(III) Complexes
Authors: Yamamoto Yoshihisa , Toyota Eiko
Published: July 2006

Ethylenediaminebis(2-methyl-8-quinolinolato)cobalt(III) complexes and bis(ethylenediamine)(2-methyI-8-quinolinolato)cobalt(III) complexes have been isolated and characterized by analytical and spectroscopic methods. In the former complexes, the NMR spectra indicate that the two nitrogen atoms of the coordinated 2-methyl-8-quinolinolato ligands are in the trans positions, whereas the two oxygen atoms are in the cis positions.
The Substituent Effects in Thiophene Compounds. III. 1H NMR and IR Studies in Methyl [trans-β-(Substituted 2-thienyl)acrylate]s
Authors: Satonaka Hajime
Published: July 2006

The 1H NMR spectra and IR C=O stretching frequencies of methyl [trans-β-(3-, 4-, and 5-substituted 2-thienyl)acrylate]s are reported. The chemical shifts of the ring protons in methyl [trans-β-(4- and 5-substituted 2-thienyl)acrylate]s are correlated linearly with those of the corresponding protons in substituted thiophenes and methyl (substituted 2-thiophenecarboxylate)s. The substituent effects on the chemical shifts of α-protons in methyl [trans-β-(3- and 5-substituted 2-thienyl)acrylate]s have been interpreted by the mesomeric effect of the substituentes. The plots of the coupling constants in methyl [trans-β-(substituted 2-thienyl)acrylate]s against those in substituted thiophenes and methyl (substituted 2-thiophenecarboxylate)s gave good linear correlations. The IR C=O stretching wave numbers showed a narrow range of variation. The coupling constants in methyl [trans-β-(substituted 2-thienyl)acrylate]s were found to vary linearly with the electronegativity of the substituents.
Regioselective Homo- and Codimerization of 1-Alkynes Leading to 2,4-Disubstituted 1-Buten-3-ynes by Catalysis of a (η5-C5Me5)2TiCl2/RMgX System
Authors: Akita Munetaka , Yasuda Hajime , Nakamura Akira
Published: July 2006

A series of 1-alkynes (RC≡CH where R=Et, n-Pr, n-Bu, n-C6H13, cyclohexyl, Ph, Me3Si, Me3SiCH2, and Me3SiOCH2) was found to dimerize regioselectively (>99%) to 2,4-disubstituted 1-buten-3-ynes in 92–99% yields by catalysis of (η5-C5Me5)2TiCl2/i-PrMgBr at 30 °C in 1–3 h. The catalyst system is also effective for the regioselective codimerization of various 1-alkynes with 1-ethynylcyclohexene or ethynylbenzene.
Studies of the Selective Adsorption of Anions by Metal Ion Loaded Ion-exchange Resin. VI. The Adsorption Behavior of the Phosphate Ion on the Iron(III) Loaded Ion-exchange Resin
Authors: Yoshida Isao , Takeshita Ryoichi , Ueno Keihei
Published: July 2006

Adsorption isotherms for the phosphate ion by various iron(III)-loaded ion-exchange resins(IRC-Fe(III)), which are different in iron(III)-ion concentrations, were prepared at 5–35 °C in aqueous systems with pH values of 3 and 4.6 by means of the batch method. These isotherms could be represented by the Cp=Q∞(Cp⁄Q)−1⁄K equation in the phosphate-ion-concentration range from 3.23×10−4 to 3.23×10−2 mol dm−3 (10 ppm to 1000 ppm as P), where Cp and Q are the phosphate-ion concentrations of the aqueous phase and the adsorbent respectively; Q∞ is the saturated phosphate concentration of the adsorbent, and K is the equilibrium constant. From the analysis of adsorption isotherms, the values for Q∞ and K were determined on each adsorbent, and the nature of the adsorbent IRC-Fe(III) was discussed, with consideration paid to these two parameters and the pH-dependency of the distribution ratio of the phosphate ion between the aqueous phase and the adsorbent.
Base-induced Dehydrosulfinatocyclization of N-Alkyl-N-phenylsulfonyl-N″-arylbenzamidrazones to 3,4-Diaryl-4H-1,2,4-triazoles
Authors: Ito Suketaka , Tanaka Yumo , Kakehi Akikazu
Published: July 2006

3,4-Diaryl-4H-1,2,4-triazoles were obtained in good to comparable yields by the reaction of N-alkyl-N-phenylsulfonyl-N″-arylbenzamidrazones with sodium hydride. The reaction probably proceeds via the elimination of benzenesulfinic acid and the oxidative cyclization of N-alkylidene-N″-arylbenzamidrazones generated by the base-catalyzed isomerization of azo intermediates.
The Catalytic Isomerization of Butenes over a Graphite Oxide
Authors: Tsuchiya Susumu , Mikami Masahiro , Imamura Hayao
Published: July 2006

The relative rate constants and the activation energies of the isomerization of butenes over a graphite oxide have been measured, The reactivity of butenes and the selectivity ratios are in agreement with the characteristics of acid catalysts. The reaction profile shown on the triangular graph is of the rake-type.
Proton Chemical Shift Study of the Hydrophobic Interaction between Tris(1,10-phenanthroline)ruthenium(II) Ions in Aqueous Solutions
Authors: Masuda Yuichi , Yamatera Hideo
Published: July 2006

The proton NMR chemical shifts were measured in the D2O solutions of [Ru(phen)3]SO4. The proton resonances of the phenanthroline ligand showed up-field shifts with increasing concentration of [Ru(phen)3]SO4, but they were not significantly affected by the addition of Na2SO4. The profile of the up-field shifts for the Λ-[Ru(phen)3]SO4 solution was different from that for the rac-[Ru(phen)3]SO4 solution. These results prove that the up-field shifts were caused by the interaction between[Ru(phen)3]2+ ions. Assuming the formation of the triple and quadrupole aggregates containing two [Ru(phen)3]2+ ions, the association constants of these aggregates and the up-field shifts of the proton signals in the aggregates were determined. A probable structure of the aggregates was deduced from the measured chemical shifts by attributing the up-field shift in the aggregates to the ring-current effect of the phenanthroline ligand. The importance of the hydrophobic interaction between [Ru(phen)3]2+ ions in aqueous solution was thus indicated.
On the Reduction Products of Carbon Dioxide at a p-Type Gallium Phosphide Photocathode in Aqueous Electrolytes
Authors: Ito Kaname , Ikeda Shoichiro , Yoshida Makoto , Ohta Soji , Iida Takaya
Published: July 2006

Formic acid, formaldehyde, and methanol, previously reported as photoelectrochemical reduction products of CO2, were observed to be obtained also by photolysis of cell materials such as electrolytes and epoxy resin. The reduction product of CO2 at a p-GaP photocathode in aqueous electrolytes was experimentally confirmed to be mainly formic acid.
The Sensitization Effect in the Laser-induced Infrared Fluorescence Spectroscopy by Addition of a Second Component. III
Authors: Higuchi Seiichiro , Kagawa Yasuhiro , Tanaka Shigeyuki
Published: July 2006

The sensitization effect in the infrared fluorescence spectra for diethyl ether–alkene systems has been examined in terms of the quantity and the kind of alkenes added as sensitizers. The sensitivity seems to be determined by the molar ratios between diethyl ether and alkenes, and the sensitization degree lowers in an orderly fashion as the alkene molecules become larger.
Polarographic Minimum Wave of Tetraiodocadmate(II) Complex in Acetonitrile
Authors: Nagaosa Yukio , Tanaka Isao
Published: July 2006

Tetraiodocadmate(II) anion gives a polarographic minimum wave at potentials above −1.1 V vs. Ag/AgCl, when tetrabutylammonium iodide is used as a supporting electrolyte. The experimental results show that the minimum wave appears as a result of electrostatic repulsion between the cadmate(II) anion and the negatively charged mercury surface.
Preparation and Characterization of (l-Histidinato)(l-methioninato)cobalt(III) Bromide
Authors: Okamoto Ken-ichi , Maki Hiroko , Hidaka Jinsai
Published: July 2006

The (l-histidinato)(l-methioninato)cobalt(III) complex was prepared and separated into three geometrical isomers by ion-exchange chromatography. The isomers were characterized from their absorption, 1H NMR, and CD spectra.
The Incorporation of Dicarboxylates into Octacalcium Bis(hydrogenphosphate) Tetrakis(phosphate) Pentahydrate
Authors: Monma Hideki
Published: July 2006

Octacalcium bis(hydrogenphosphate) tetrakis(phosphate) pentahydrate (OCP) has been found to complex with saturated aliphatic dicarboxylate ions, CnH2nC2O42−; n=1–6. These organic substances were incorporated, instead of HPO42−, into the “B-layer” of the OCP structure. The incorporation caused expansion in the basal spacing (d100) of OCP from 18.7 Å to 19.6–26.1 Å. A possible structural model is proposed for the incorporation.
Catalytic Conversion of Allylic Esters to Corresponding Allylic Silanes with Hexamethyldisilane and Palladium(0) or Rhodium(I) Complexes
Authors: Urata Hisao , Suzuki Hiroharu , Moro-oka Yoshihiko , Ikawa Tsuneo
Published: July 2006

Treatment of allylic esters (R1CH=CR2CH2OCOR3: R1=H, Ar; R2=H, alkyl; and R3=Me, Ph) with hexamethyldisilane in the presence of catalytic amounts of PdL4 (L=PPh3 or P(OPh)3) or RhCl(PPh3)3 gives the corresponding allylic silanes in the excellent yield.
A Convenient Synthesis of 3-Aminotropolone and Its Reactions with Orthoesters. Formation of 8H-Cyclohept[d]oxazol-8-ones
Authors: Imafuku Kimiaki , Furuya Miki , Jin Zhong-Tian
Published: July 2006

Schmidt reaction of 3-acetyltropolone gave 3-acetamidotropolone, which was hydrolyzed to afford 3-aminotropolone (3). The compound 3 reacted with orthoformate, orthoacetate, orthopropionate, and orthobenzoate to give the corresponding 2-substituted 8H-cyclohept[d]oxazole-8-one derivatives.
A Simple and Convenient Method for the Synthesis of Sulfones Using Polyethylene Glycols or Their Dialkyl Ethers as Solvents or Catalysts
Authors: Sukata Kazuaki
Published: July 2006

Various alkyl p-tolyl sulfones were prepared in good yields under mild conditions in the presence of polyethyene glycols or their dialkyl ethers as solvents or catalysts.
Synthetic Photochemistry. XXVII. An Efficient Synthesis of Deoxytrisporone by Photocycloaddition
Authors: Takeshita Hitoshi , Hatta Seiji , Hatsui Toshihide
Published: July 2006

Deoxytrisporone was synthesized from isobutene and methyl 2,4-dioxohexanoate to show the utility of the regioselective photocycloaddition of β-diketone for construction of polysubstituted cyclohexenones.
The 2H-Cyclohepta[b]furan-2-one Formation from 2,4-Dichloro-5-methoxytropone with Dimethyl Malonate and Methyl Acetoacetate
Authors: Takeshita Hitoshi , Mori Akira , Minami Tomoyoshi
Published: July 2006

2,4-Dichloro-5-methoxytropone afforded 3,5,6-trisubstituted 2H-cyclohepta[b]furan-2-one derivatives by condensation with dimethyl malonate and methyl acetoacetate in an exclusive ciné-condensation mode in various solvents.
Reactions of 3-Acetyltropolone Methyl Ethers with 1,2-Cyclohexanediamine
Authors: Sudoh Yasunori , Imafuku Kimiaki
Published: July 2006

3-Acetyl-2-methoxytropone reacted with 1,2-cyclohexanediamine (2) (a mixture of cis 60% and trans 40%) to give four cis-trans pairs of 6-acetyl-5H-1,2,3,4,4a,11a-hexahydrocyclohepta[b]quinoxaline (3), 6-acetyl-9-formyl-1,2,3,4,4a,5,10,10a-octahydrophenazine (4), 6-acetyl-1,2,3,4,4a,5,10,10a-octahydrophenazine (5), and 1-methyl-6H-6a,7,8,9,10,10a-hexahydropyrrolo[3,2,1-de]phenazine (6). The reaction of 2-acetyl-7-methoxytropone with 2 gave cis- and trans-N,N′-bis(6-acetyl-7-oxo-1,3,5-cycloheptatrienyl)-1,2-cyclohexanediamine, besides the above products. The cis- and trans-isomers of 4, 5, and 6 were secondary products from the cis- and trans-isomers of 3, respectively.
The Preparation of 1-Carbamoyl-3-cyanoguanidine and 1-Cyanobiuret from Cyanourea
Authors: Iio Kokoro
Published: July 2006

Cyanourea in an aqueous or organic solution which was allowed to stand at room temperature gave 1-carbamoyl-3-cyanoguanidine and 1-cyanobiuret. The reaction was promoted by a mixture of cyanourea and its alkali salt. 1-Cyanobiuret was also obtained quantitatively by the reaction of cyanourea with alkali cyanate.
Nonisothermal Kinetics of Crystal Growth from Preexisting Nuclei
Authors: Ozawa Takeo
Published: July 2006

Fundamental kinetic equations for nonisothermal crystal growth from preexisting nuclei are derived, by introducing a concept of reduced time. A method of kinetic analysis of thermoanalytical data of these processes is proposed, and all kinetic parameters can be estimated by the method, so that the process proceeding under various temperature changes can also be predicted.
The Structure of Liquid Alcohols by Neutron Diffraction. I. Molecular Structure of Methyl Alcohol
Authors: Tanaka Yukio , Ohtomo Norio , Arakawa Kiyoshi
Published: July 2006

The structure factor Sm(Q) for liquid methyl alcohol (CD3OD) at room temperature was obtained by means of the LINAC-TOF neutron diffraction method. An analysis of the diffraction data was carried out, and the molecular structure of CD3OD in liquid phase was determined as: the O–D, C–O, and C–D bond lengths are 0.990±0.010, 1.435±0.005 , and 1.085±0.005 Å, respectively. The O–D and C–D lengths were found to be longer than those values determined in gaseous phase.
ENDOR Study of Benzothiazolone Azine Cation Radicals by Means of a TM110 Mode Cavity
Authors: Lopez Javier , Yamauchi Jun , Okada Keiichi , Deguchi Yasuo
Published: July 2006

The electron nuclear double resonance (ENDOR) spectra of benzothiazolone azine cation radicals were observed by means of an ENDOR spectrometer equipped with a TM110 mode cavity. Highly diluted solutions of the radicals and a high radiofrequency power of 300 W facilitated the ENDOR observation. The obtained ENDOR values are different from the previously published results determined only from the ESR data, especially for the substituted alkyl groups. The assignment of the hyperfine coupling constants was made on the basis of the molecular orbital calculations as well as the re-examination of the ESR spectrum simulation. Good agreement between the calculated and the measured spectra is obtained if one assumes that the hyperfine coupling constants of the two different sets of nitrogen nuclei are equal as has been pointed out earlier.
Sodium Sulfate Doped with Sodium Vanadate and Rare Earth Sulfate as a Solid Electrolyte for a Sulfur Dioxide Gas Detector
Authors: Imanaka Nobuhito , Adachi Gin-ya , Shiokawa Jiro
Published: July 2006

Sodium sulfate doped with NaVO3 and Ln2(SO4)3 (Ln=Eu, Pr, and Y) show higher electrical conductivity for Na+ ions and maintains a high temperature phase, Na2SO4–I, without showing phase transformation. The electromotive force (EMF) using solid solutions, Na2SO4–NaVO3–Ln2(SO4)3 (Ln=Pr and Y), as solid electrolytes exhibits good agreement with the calculated value, the temperature as low as 673 K which is approximately 300 K lower than pure sodium sulfate can be.
Kinetics of the Conformational Change and Subunit Dissociation of Aldolase
Authors: Ohga Yoko , Nakanishi Mamoru , Tsuboi Masamichi
Published: July 2006

The kinetics of acid denaturation of muscle aldolase were examined by stopped-flow fluorescence and stopped-flow light scattering measurements. The denaturation reaction was found to consist of three distinguishable steps—step I with fluorescence increase only, step II with both fluorescence increase and light scattering decrease, and step III with fluorescence decrease alone. Circular dichroism and sedimentation equilibrium measurements were also made at different pH’s in the course of the acid denaturation. It was concluded that in the acid denaturation of this enzyme a rearrangement of the secondary or tertiary structures takes place rapidly (4 s−1 at 21.5 °C and at pH 3.4), and then the subunit dissociation occurs more slowly (0.04 s−1 at 21.5 °C and at pH 3.4), with further conformational change. The subunit dissociation was found to be caused by two H+ per tetramer.
Induction of the β-Form of Poly(S-carboxymethyl-l-cysteine) and Poly[S-(2-carboxyethyl)-l-cysteine] by Chromium(III), Iron(III), and Lanthanum(III) Chlorides
Authors: Oka Kazuki , Maeda Hiroshi , Ikeda Shoichi
Published: July 2006

The β-form was induced by the addition of CrCl3, FeCl3, and LaCl3 to the salt-free solutions of fully ionized poly(S-carboxymethyl-l-cysteine) (poly[Cys(CH2COOH)]) and poly[S-(2-carboxyethyl)-l-cysteine] (poly[Cys(CH2CH2COOH)]). The induction occurred below the equivalent point in both polypeptides. The inducing powers of the three trivalent cations were rather similar. They were weaker than Cu2+ ions in the case of poly[Cys(CH2COOH)], while they were comparable with Cd2+ ions in the case of poly[Cys(C2H4COOH)]. Cu2+ and Cd2+ ions were the most effective species among divalent cations in the induction of the β-form of poly[Cys(CH2COOH)] and Poly[Cys(C2H4COOH)], respectively.
Response Time Curves of Neutral Carrier Membrane Electrode of Tubular Shape
Authors: Degawa Hisao , Shinozuka Noriko , Hayano Shigeo
Published: July 2006

A tubular flow-through electrode system for measuring the response time curves under the step change of concentration using an ammonium ion-selective poly(vinyl chloride) membrane electrode was described. The response time data are analyzed by the curve fitting method using two theoretical equations, which are an exponential type equation based on an assumption of the film diffusion and a square root type one based on that of the diffusion within the membrane, and a semiempirical equation of hyperbolic type. A method of curve fitting in which the equilibrium potential is regarded as an unknown parameter was described in detail. The initial part of the response time curves, where the potential change is large, was fitted by the exponential type equation, while the following part close to the equilibrium potential was fitted by the square root type one. The semiempirical equation could also be fitted to the wide range of the curves. The dependence of the time constant of the exponential type equation upon the flow rate of sample solution is examined; the results firmly supports both the film diffusion as a determining process for the initial part of the curve and the reliability of the present experimental system.
Synthesis of [3](1,1′)[3](3,3′)- and [4](1,1′)[4](3,3′)Ruthenocenophanes
Authors: Kamiyama Shin-ichi , Kasahara Akira
Published: July 2006

[3](1,1′)[3](3,3′)- and [4](1,1′)[4](3,3′)Ruthenocenophanes were synthesized via cyclization of the propionic acid derivatives of [3](1,1′)- and [4](1,1′)ruthenocenophanes with polyphosphoric acid or trifluoroacetic anhydride, respectively. The 1H NMR, IR, and electronic spectra of these dibridged ruthenocenes were measured and compared with those of monobridged ruthenocenes.
The Reaction of Cyclic 1,3-Diketones with Alkylthiocydopropenium Ions to Yield 2-Alkylthio-substituted 2H-Pyrans
Authors: Yoshida Hiroshi , Nakajima Mikito , Ogata Tsuyoshi , Matsumoto Kiyoshi
Published: July 2006

This study treats the reactions of methylthio-, ethylthio-, or benzylthiodiphenylcyclopropenium ion (1) with 5-, 6-, and 7-membered cyclic 1,3-diketones, giving either 2-alkylthio-2H-pyrans or dienone derivarives. Treatment of 1 with 1,3-cyclopentanedione, 1,3-cyclohexanedione, 5,5-dimethyl-1,3-cyclohexanedione, 4-hydroxy-6-methyl-2-pyrone, 4-hydroxycoumarin, and 1,3-cycloheptanedione in the presence of triethylamine afforded 2-alkylthio-2H-pyrans. The structure of the products was elucidated on the basis of their elemental analyses, IR, 1H-NMR, 13C-NMR, and mass spectroscopic data, as well as chemical transformations. 2-Alkylthio-2H-pyrans with mercury(II) chloride in an alcohol underwent conversion to the corresponding 2-alkoxy-2H-pyrans. The 1H- and 13C-NMR data of these compounds clearly show that the equilibrium lies completely on the side of the 2H-pyran. In contrast, the reaction of 1 with 1,3-indandione yielded the ring-opened dienone derivative as a mixture of E and Z isomers.
An Electrochemical Study on Anion Doping-Undoping Process of Polyacetylene by Means of FFT Impedance Measurement
Authors: Osaka Tetsuya , Kitai Takashi
Published: July 2006

An electrochemical anion doping-undoping process of cis-polyacetylene, (CH)x, was investigated in 1 mol dm−3 LiClO4 or LiBF4 in propylene carbonate by the FFT impedance measurement. This could be applied to the system with time-variation because of its high speed measuring duration. The doping-undoping process of the anion was represented by the Randles-type equivalent circuit, considering the corrective term concerned with surface roughness. The impedance behavior of the doping-undoping process was pursued by the variation of resistive component, Rr. The value of Rr was mainly reflected by the dopant concentration at the surface. The variation of Rr indicated that rapid or strong-drive doping produces non-uniformity of dopant distribution in the film and high dopant concentration at the surface.
Oxidation Potential of Intramolecular Exciplex on a Vinyl Copolymer as Estimated by Electron-transfer Quenching Reactions
Authors: Iwai Kaoru , Takemura Fukuo , Furue Masaoki , Nozakura Shun-ichi
Published: July 2006

In the electron-transfer reaction from the fluorescent intramolecular exciplexes of a copolymer containing phenanthrene and N,N-dimethylaniline moieties, and of a model compound to electron acceptors, the reactivity of the exciplexes was studied kinetically in polar and nonpolar media. The copolymer was poly(9-vinylphenanthrene-co-p-dimethylaminostyrene) and the model compound was N,N-dimethyl-4-[3-(9-phenanthryl)propyl]aniline. The oxidation potential of the exciplex was evaluated by the relation of the exciplex-quenching rate constants to the reduction potentials of electron-accepting quenchers according to the equations of Rehm and Weller. It was found that the electron-donating ability of these intramolecular exciplexes resembled with each other and was larger than that of excited phenanthrene. In polar media the donating ability was very close to that of the phenanthrene anion radical.
Oxygen- and Carbon Monoxide-binding Affinity of the Liposomal Heme under Semiphysiological Conditions
Authors: Tsuchida Eishun , Nishide Hiroyuki , Yuasa Makoto , Sekine Mikiya
Published: July 2006

Oxygen- and carbon monoxide-binding affinity (P1⁄2) of the [α,α,α,α-meso-tetrakis(o-pivalamidophenyl)porphinato]iron(II)-mono(1-dodecyl-2-methylimidazole) complex incorporated in liposome of phosphatidylcholine (abbreviated as liposomal heme) were measured in pH 7.0 aqueous solution at 15–37 °C. The P1⁄2(O2) and P1⁄2(CO) values at 37 °C were 49 and 0.02 mmHg, respectively. Enthalpy and entropy changes for the reversible bindings were similar to those of hemoglobin. The relationship between temperature and P1⁄2 for the dimyristoylphosphatidylcholine-liposomal heme had a breaking point at ca. 24 °C, which agreed with the phase transition temperature of the liposomal heme.
A New and Effective Synthetic Method for the Preparation of the Esters, Peptides, and Lactones Using 3-(5-Nitro-2-oxo-1,2-dihydro-1-pyridyl)-1,2-benzisothiazole 1,1-Dioxide. Synthesis of (±)-(E)-8-Dodecen-11-olide, Recifeiolide
Authors: Ahmed Alauddin , Taniguchi Nagahiro , Fukuda Hirohiko , Kinoshita Hideki , Inomata Katsuhiko , Kotake Hiroshi
Published: July 2006

3-(5-Nitro-2-oxo-1,2-dihydro-1-pyridyl)-1,2-benzisothiazole 1,1-dioxide(BID-NPy), readily prepared from 3-chloro-1,2-benzisothiazole 1,1-dioxide and 5-nitro-2-pyridone, proved to be a very useful condensing reagent. A variety of esters, dipeptides, and lactones were obtained in excellent yields. Furthermore, BID-NPy was successfully employed for the lactonization step in a new synthesis of a naturally occurring (±)-(E)-8-dodecen-11-olide, recifeiolide.
Intramolecular Cycloaddition of Two Acyl-1,4-benzoquinone Moieties on Photolysis
Authors: Miyagi Yo , Maruyama Kazuhiro , Tanaka Nobuo , Sato Mamoru , Tomizu Toshinori , Isogawa Yasuhiro , Kashiwano Hisae
Published: July 2006

Upon irradiation a regio- and stereoselective cycloaddition occurred intramolecularly between two acyl-1,4-benzoquinone moieties connected by a polymethylene bridge. The regio- and stereoselectivities are different from those of the corresponding intermolecular cycloaddition; this was interpreted in terms of the Diels-Alder reaction between an acyl-1,4-benzoquinone moiety and a photochemically produced dienol.
A Convenient Synthesis of 4-(2,2-Dichloroethenyl)-5,5-dimethyltetrahydro-2-furanone Derivatives, a Key Intermediate of Permethrinic Acid
Authors: Tsuboi Sadao , Amano Eiichiro , Takeda Akira
Published: July 2006

A key intermediate of 2-(2,2-dichloroethenyl)-3,3-dimethylcyclopropanecarboxylic acid, 3-alkoxycarbonyl(or acyl)-4-(2,2-dichloroethenyl)-5,5-dimethyltetrahydro-2-furanone was prepared by the base-catalyzed condensation of 2-methyl-3,5,5-trichloro-4-penten-2-ol with acetate derivatives such as malonic esters, acetoacetic esters, and benzoylacetate. The reactivity of 3-acetyl-4-(2,2-dichloroethenyl)-5,5-dimethyltetrahydro-2-furanone to an excess amount of thionyl chloride in ethanol was also examined. An analog, 5-butyl-4-(2,2-dichloroethenyl)-3-ethoxycarbonyl-5-methyltetrahydro-2-furanone was also prepared in 31% yield.
Syntheses of Aryl Glyoxylate. I. The Reaction of Alkyl Dichloro(alkoxy)acetates with Aromatics in the Presence of Lewis Acid
Authors: Itoh Osamu , Nagata Takayoshi , Nomura Isamu , Takanaga Tetsuya , Sugita Toshio , Ichikawa Katsuhiko
Published: July 2006

Ethyl dichloro(ethoxy)acetate (1) and methyl dichloro(methoxy)acetate (2) were characterized. The reaction of 1 and 2 with aromatics in the presence of AlCl3 gave a considerable yield of aromatic α-keto ester. The aromatics included mono- and polymethylbenzene and anisol. The reaction was studied under various conditions and the results were compared with the acylation by ethoxalyl or methoxalyl chloride. The reaction mechanism was also discussed.
Studies of Bitter Peptides from Casein Hydrolyzate. X. Synthesis and Bitter Taste of H–Arg–Gly–Pro–Phe–Pro–Ile–Ile–Val–OH Corresponding to C-Terminal Portion of β-Casein
Authors: Kanehisa Hidenori , Miyake Ichizo , Okai Hideo , Aoyagi Haruhiko , Izumiya Nobuo
Published: July 2006

In order to ascertain the validity of the structure of bitter peptide BPIa (H–Arg–Gly–Pro–Pro–Phe–Ile–Val–OH) isolated from casein hydrolyzate by Minamiura et al., the C-terminal octapeptide of β-casein (H–Arg–Gly–Pro–Phe–Pro–Ile–Ile–Val–OH) determined by Ribadeau Dumas et al., which is assumed to correspond to BPIa, was synthesized and compared with the synthetic BPIa which was confirmed to be identical with the natural one. The two synthesized peptides, however, did not match on thin-layer chromatography. The result indicates that the structure of BPIa need not be converted to Ribadeau Dumas’ formula. The octapeptide possessed an extremely bitter taste, with a threshold value of 0.004 mM (1 M=l mol dm−3). It is the most bitter peptide.
Interactions between Anionic Surfactants and Oil Dyes in the Aqueous Solutions. III. Thermochromism in the Presence of Surfactant Micelle and Dye–Surfactant Complexes
Authors: Abe Masahiko , Ohsato Mitsuo , Suzuki Nobuyuki , Ogino Keizo
Published: July 2006

The interactions between 4 anionic surfactants and 3 azo oil dyes have been studied by a spectrophotometer. The spectrographic behavior of these solutions was dependent on the kinds of hydrophilic groups in each surfactant and the kind of auxochrome in the azo oil dyes. In particular, a sulfate and two sulfonates including strongly hydrophilic groups interacted strongly with the oil dyes (4-NH2) which have an amino group at 4-position of naphthalene. At lower concentrations, an isosbestic point was recognized; this occurred because of the formation of the hydrophobic dye–surfactant complex (1:1). In the neighborhood of the cmc region, the spectrum with a peak at 520 nm changed with temperature into another one with a 440 nm band; this is the so-called thermochromism. This may be attributed to the fact that, in the presence of surfactant micelles, the 4-NH2 exhibits an azo form at higher temperature, but a resonance stabilized azonium form is found at lower temperature.
Structural Characterization of Soluble Products from a Series of Reductively Butylated Coals Prepared in Refluxing Tetrahydrofuran
Authors: Miyake Mikio , Sukigara Masayuki , Nomura Masakatsu , Kikkawa Sh\={o}ichi
Published: July 2006

A series of butylated Y\barubari coals were prepared by an improved reductive alkylation method, and detailed structural parameters of respective solution products in pentane (PS) and benzene (BS) were estimated; this experimental procedure is likely to offer more insight into chemical structures of products and important factors effective for solubilization than any analyses on a single product. The PS and BS have average molecular weights of 700–800 and 1500–2050 and are composed of about two and more than five structural units, respectively. These values suggest that the BS molecule is quite large compared with the corresponding products obtained by other methods such as hydrocracking. On the other hand, the ring sizes of one structural unit of the respective products are roughly the same (about three rings). The BS materials are coal macromolecules with stackings loosened by introduction of alkyl groups, while the PS materials are products through cleavage of bonds connecting the structural units and through addition of so many alkyl groups as to increase the affinity for the solvent. In addition, an absence of intermolecular hydrogen bonds mainly due to OH groups contributes to quite a high solubility of the alkylated coals. Increase in BS yield accompanies an increase in aliphatic carbon ratio and polymerization degree and a decrease in size of aromatic ring systems. These results may be ascribed to the heterogeneity of coal constituents.
N,N′-Carbonyldi[2(3H)-benzoxazolethione]: New, Reactive Condensing Agent for the Synthesis of Amides, Esters, Peptides, and Polyamides
Authors: Ueda Mitsuru , Kawaharasaki Naomi , Imai Yoshio
Published: July 2006

A new condensing agent, N,N′-carbonyldi[2(3H)-benzoxazolethione] (3), was readily prepared by the reaction of 2-benzoxazolethiol and trichloromethyl chloroformate in benzene. The condensing agent 3 is shown to be useful for the preparation of amides, esters, and dipeptides under mild conditions. A successful polyamide synthesis by the polycondensation of isophthalic acid with diamines using 3 is also described.
The Electronic Structure of Heterotropones. Photoelectron Spectra and Molecular Orbital Calculations
Authors: Gleiter Rolf , Bischof Peter , Böhm Michael C , Guilard Roger , Yamaguchi Hiroyuki
Published: July 2006

Using a helium discharge lamp with an energy of 21.21 eV (He(I)α line) the photoelectron (PE) spectra of the heterotropones 1–7 have been investigated and compared with the PE spectra of benzologue tropones and with the PE data of thiophene, furan and pyrrole. The first five ionization events in the PE spectra of 1 to 7 could be assigned to electron ejections from 2a2(π), 4b1(π), 9b2(n), 3b1(π), and 1a2(π) orbitals. This assignment has been deduced by means of experimental correlation techniques and using ZDO calculations of the LCBO and HMO type as well as semiempirical SCF versions (MINDO/3 and PPP).
Ion Exchange Equilibria between Alkali Metals and Hydrogen Ions on Iron(III) Antimonate, an Inorganic Ion Exchanger
Authors: Rawat Jagdish Prasad , Singh Balbir
Published: July 2006

Ion exchange equilibria of alkali metal ions (Li+, Na+, K+ and Rb+)/H+ systems have been studied at 30, 40, 50, and 60 °C on iron(III) antimonate as a cation exchanger. The exchange isotherms have been measured for both forward and backward reactions with solutions of ionic strength 0.1 by the batch technique. The isotherms showed S-shaped curves for each exchange system except Li+/H+. Selectivity coefficients vary with the equivalent fraction (\barXM) of the alkali metal ions in the exchanger and give linear functions against \barXM in the range from 0–0.40. The selectivity sequence shows Na+<Li+<K+<Rb+. The overall thermodynamic data are evaluated.
Effect of Urea on Hydrophobic Side Chain Interactions in Polypeptides at the Air–Water Interface
Authors: Shibata Akira , Yamashita Shinsuke , Yamashita Takuya
Published: July 2006

The surface activity of urea at the polypeptide monolayer–water interface was investigated by the surface pressure analysis. The expansion of the monolayer is attributed to the penetration of polypeptide monolayer by urea in the subsolution. The hydrophobic side chain interactions in polypeptides are weakened by the action of urea. The surface activity of urea depends on the difference in the chemical composition and the geometrical arrangement of side chains between benzyloxycarbonyl derivatives of basic poly(α-amino acid) and benzyl esters of acidic poly(α-amino acid).
Studies on Lanthanoids–Antimony–Chalcogenides. III. Synthesis and Crystal Data of Nd3SbS6, Ce6Sb8S21, and Ce3Sb3S10
Authors: Gao Jin-zhang , Nakai Izumi , Nagashima Kozo
Published: July 2006

Single crystals of three new sulfides were prepared in evacuated silica tubes heated in the temperature range 890–1200 °C. Nd3SbS6 is a red transparent crystal. Is is tetragonal, space group I41/acd with lattice parameters a=15.54(1) and c=19.52(2) Å. Ce6Sb8S21 and Ce3Sb3S10 are isostructural with La6Sb8S21, and La3Sb3S10, respectively.
Pressure and Temperature Effects on Octahedral-Tetrahedral Equilibria in Pyridine Solutions of Some Cobalt(II) Halides. II
Authors: Kojima Kazuo , Miyashita Takeru , Matsuda Jiro
Published: July 2006

Temperature and pressure effects on the configuration equilibrium of cobalt(II) iodide in pyridine solution have been studied spectrophotometrically. High temperature favors the tetrahedral species but high pressure favors the octahedral species, the heat and volume changes being 65.3 kJ mol−1 and −6 cm3 mol−1, respectively. Comparisons among three kinds of halide are also made.
13C-NMR Spectra of 2-Aryl-2-(1-azolylmethyl)-4-hydroxymethyl-1,3-dioxolanes and Their Ester and Ether Derivatives
Authors: Suezawa Hiroko , Hirota Minoru , Yamamoto Kazuko , Takeuchi Isao , Hamada Yoshiki
Published: July 2006

The 13C-NMR spectra of the title compounds were assigned and the substituent effect was discussed briefly. 13C-NMR of 2-aryl-4-benzoyloxymethyl-2-bromomethyl-1,3-dioxolanes provides the way to discriminate the cis and the trans isomers.
Mechanochemical Racemization of l-Leucine
Authors: Ikekawa Akiko , Hayakawa Sohachiro
Published: July 2006

On treating a ball-milled mixture of l-leucine and such diluents as silicone dioxide in hydrochloric acid, a part of l-leucine was transformed into d-leucine.
Preparation of New Nitrogen-bridged Heterocycles. 7. Reactions of 3-[Bis(methylthio)methylene]-2(3H)-indolizinones with Some Pyridinium N-Aminides
Authors: Kakehi Akikazu , Ito Suketaka , Wada Bunzo
Published: July 2006

The reactions of 3-[bis(methylthio)methylene]-2(3H)-indolizinones with pyridinium, quinolinium, and isoquinolinium N-aminides gave unstable 1,3-dipolar spiro-adducts with the elimination of a methanethiol, and some of these adducts isomerized thermally to afford the corresponding N-ylide derivatives.
Studies of Bitter Peptides from Casein Hydrolyzate. IV. Relationship between Bitterness and Hydrophobic Amino Acids Moiety in the C-Terminal of BPIa (Arg–Gly–Pro–Pro–Phe–Ile–Val)
Authors: Otagiri Ken , Shigenaga Toshiaki , Kanehisa Hidenori , Okai Hideo
Published: July 2006

In the synthetic studies of bitter peptide BPIa (Arg–Gly–Pro–Pro–Phe–Ile–Val), we synthesized several BPIa analogs to elucidate the participation of the hydrophobic amino acids moiety in the C-terminal in the bitter taste exhibited by BPIa. The syntheses of the peptides were performed by the usual MA (mixed anhydride) and DCC (dicyclohexylcarbodiimide)–HOBt (1-hydroxybenzotriazole) method, and the bitterness of the peptides was organoleptically determined. The BPIa analogs in which more than two hydrophobic amino acids were located in the C-terminal exhibited a bitter taste as strong as that of BPIa.
The Reaction of 1,1-Dimethyl-1-Phenacylhydrazinium Bromide with Aqueous Sodium Hydroxide
Authors: Kano Kunio , Anselme Jean-Pierre
Published: July 2006

The reaction of 1,1-dimethyl-1-phenacylhydrazinium bromide with 1 M aqueous sodium hydroxide give benzoic acid, 3-phenyl-1-methylpyrazole, 5-benzoyl-3-phenyl-1-methylpyrazole, and benzonitrile as the major components; the expected product, 2-benzoyl-5-phenylimidazole was formed in only small amounts. Mechanisms to rationalize the formation of the major products are discussed.
Molecular and Crystal Structures of endo- and exo-N-Methyl-3,7-epoxy-3-methoxy-7-oxo-1,2-benzo-1-cycloheptene-4,5-dicarboximide
Authors: Tamura Hatsue , Ibata Toshikazu , Ogawa Kazuhide
Published: July 2006

The crystal structures of endo- and exo-adducts of 1-methoxy-2-benzopyrylium-4-olate with N-methylmaleimide have been determined by means of X-ray analysis. The colorless crystals of the endo-adduct are orthorhombic, with the space group P212121 and with a=14.432(3), b=11.874(2), c=7.762(1) Å, and Z=4. The colorless crystals of the exo-adduct are monoclinic, with the space group P21/a and with a=13.381(2), b=12.825(1), c=7.4793(4) Å, β=92.13(1)°, and Z=4. The structures were deduced by a direct method and refined by a block-diagonal least-squares technique. The final R values for the endo- and exo-adducts are 0.047 for 1160 observed reflections and 0.067 for 1986 observed reflections respectively. The configurations of the endo- and exo-adducts are coincident with those assigned on the basis of the NMR data. The observed values of the ring-current effect on the N-methyl chemical shift of the endo-adduct and the coupling constants of the vicinal methine protons of both adducts are in good agreement with the ones calculated on the basis of the present X-ray crystal-structure analysis.
ESR Studies of Paramagnetic Species Trapped in Single Crystals of Chloro(5,10,15,20-tetraphenylporphyrinato)cobalt(III)
Authors: Kohno Masahiro , Ohya-Nishiguchi Hiroaki , Yamamoto Kiyoko , Sakurai Tosio
Published: July 2006

The ESR spectra of three paramagnetic species trapped in single crystals of chloro(5,10,15,20-tetraphenylporphyrinato)cobalt(III) (CoIIICl(tpp)), have been observed at 4.2 K to room temperature. Based on the ESR parameters obtained, the paramagnetic species have been identified as two CoII(tpp) with different axial ligand effects and a previously reported cation radical, [CoIII(tpp)]2+·(Cl−)2. A correlation diagram among g, A, and axial ligation made from published data of cobalt(II) complexes has been successfully used for identification of the two trapped CoII(tpp) species: one is four-coordinate CoII(tpp) and the other five-coordinate CoIIX(tpp) in which X is presumably Cl−. Their electronic and molecular structures are discussed according to McGarvey’s theory. Finally, the formation mechanism of the three paramagnetic species in CoIIICl(tpp) is discussed, based on the results obtained from the single crystalline ESR measurements.
Studies of Acylamino Acid Monolayers by π-A curves. I. Acylamino Acids with Alkyl Side Chain
Authors: Takahashi Katashi , Tanaka Fudeko , Motomura Kinsi
Published: July 2006

In order to obtain some information regarding the behavior of amino acids at interfaces, the monolayers of N-acyl l-α-amino acids with alkyl side chains on water have been investigated by measuring the surface pressure vs. area curves at various temperatures. It has been found that N-octadecanoylglycine and N-octadecanoylalanine form the condensed monolayers over the whole surface pressure range measured, N-octadecanoylvaline forms the expanded monolayer at a lower surface pressure, and N-octadecanoylleucine and N-octadecanoylisoleucine collapse at high surface pressures. From the experimental results, it has been concluded that the amino acid residue with a long side chain occupies a large area at the air/water interface and interferes with the condensation of acylamino acid monolayer. It has also been found that the methyl esterification of amino acid residue makes the monolayer state unstable although it produces less significant effect than the increase in the alkyl chain length of amino acid residue.
A Fluorescence Study of the Adsorption of Water, Methanol, and Acetic Acid on an Activated Europium Ion-exchanged Mordenite
Authors: Arakawa Tsuyoshi , Takakuwa Midori , Shiokawa Jiro
Published: July 2006

The adsorption of water, methanol, and acetic acid on an activated Eu(III) ion-exchanged mordenite(Eu–M) has been studied by the measurement of the fluorescence of the Eu2+ ion which was produced by the dehydration at 500 °C. The emission peak of the Eu2+ ion sifted to a shorter wavelength on exposure to water and other simple molecules. The magnitude of the shift was correlated to the specific dielectric constant of the adsorbate. The quantum yield for the Eu2+ emission band after gas adsorption decreased in all cases. Also, the lifetime in the Eu2+-adsorbate system was shorter than that in an activated Eu–M sample. The rate constants for the radiationless transitions were more sensitive to the nature of the adsorbates, and the order of the quenching power was H2O>D2O>CH3OH.
Magnetic Circular Dichroism and Electronic States of Tetrachloroplatinate(II) and Tetrachloropalladate(II) Ions
Authors: Nakayama Kazuhiko , Komorita Takashi , Shimura Yoichi
Published: July 2006

The magnetic circular dichroism (MCD) spectra of K2PtCl4 and K2PdCl4 have been carefully remeasured over the visible-near UV region. The examination of the electronic absorption and the MCD spectra together with their Gaussian analyses strongly suggests that the band of K2PtCl4 at 30.3×103 cm−1 contains both Γ5(1Eg) and Γ3(1B1g)←Γ1(1A1g) transitions, and the band of K2PdCl4 at 21.1×103 cm−1 all three spin-allowed d-d transitions. The separation of the Γ2(1A2g) and Γ5(1Eg) excited states is considerably large with K2PtCl4 as compared with K2PdCl4. The MCD for the high-intensity absorption bands in K2PtCl4 is different from that reported previously. On the basis of new MCD result, the bands at 43.3 and 46.6×103 cm−1 have been assigned to d-p transitions, a2u(pz)←a1g(dz2) and eg(dxz,yz), respectively.
Spectrophotometric Determination of Lead, Zinc, and Cadmium after Extraction of Their Diethyldithiocarbamates into Molten Naphthalene and Replacement by Copper
Authors: Wasey Abdul , Bansal Raj K , Satake Masatada , Puri Bal K
Published: July 2006

A method is proposed for the extraction of lead, zinc, and cadmium as their diethyldithiocarbamates into molten naphthalene. These complexes are quantitatively extracted into molten naphthalene. After extraction, the solidified naphthalene containing the colorless complex of each of the above metals is dissolved in chloroform and the metal is replaced by copper(II) to develop a yellow color of copper(II) diethyldithiocarbamate. The absorbance is measured at 440 nm. Beer’s law is obeyed in the concentration range of 5.0–130.0 μg for lead, 3.0–60.0 μg for zinc, or 5.0–100.0 μg for cadmium in 10 ml of the final solution. The molar absorptivities (1 mol−1 cm−1) and Sandell sensitivities (μg/cm2) for lead, zinc, and cadmium are calculated to be 1.15×104, 0.0098, 1.11×104, 0.0059, and 1.15×104, 0.0098 respectively. Solutions containing 45.0μg of lead, 40.0μg of zinc, and 43.0μg of cadmium separately gave mean absorbances of 0.250, 0.620, and 0.440 with standard deviations of 0.0027, 0.0059, and 0.0038, respectively. Conditions have been decided for the determination of lead, zinc, and cadmium in some alloys and synthetic mixtures.
Preparation and Circular Dichroism Spectra of Cobalt(III) Complexes Containing an Optically Active NH2CH2CH(CH3)X−-N,X (X=S or Se) Ligand
Authors: Nakabayashi Kyoko , Doi Kaoru , Kojima Masaaki , Fujita Junnosuke
Published: July 2006

Several cobalt(III) complexes of the [Co(apS or apSe)(N4)]2+ type were prepared, where apS and apSe denote chiral 1-amino-2-propanethiolate-N,S and 1-amino-2-propaneselenolate-N,Se ligands, respectively, and N4 is (en=ethylenediamine)2, (R-chxn=(R,R)-1,2-cyclohexanediamine)2, or tren=tris(2-aminoethyl)amine. Their circular dichroism (CD) spectra were compared with one another and with those of complexes containing such ligands as achiral 2-aminoethanethiolate-N,S, 2-aminoethaneselenolate-N,Se or chiral 1-amino-2-propanolate-N,O (apO). The vicinal CD curves of S-apS obtained from CD spectra of the en and R-chxn complexes are similar and very large in magnitude in the d-d absorption band region. These curves are very similar to the CD spectrum of [Co(S-apO)(NH3)4]2+. The vicinal CD curve of S-apSe shows a similar pattern, but the magnitude is smaller than those of the S-apS and S-apO ligands. The vicinal effect of the protonated S-apSH ligand is much smaller compared with that of its conjugate base (S-apS) ligand. The tren complexes of S-apS and S-apSe exhibit CD spectra fairly different from the vicinal CD curves of the respective ligands in the d-d absorption band region.
Oxidative Degradation of Monosaccharides by Iron(III) Chlorides with a Near-UV to Visible Light under Aerobic Atmosphere
Authors: Araki Koji , Sakuma Masato , Shiraishi Shinsaku
Published: July 2006

Monosaccharides were oxidatively degraded by FeCl3 with irradiation of a near-UV to visible light under aerobic atmosphere. d-Fructose and d-arabinose were degraded to d-erythrose in a yield of more than 80 mol%. d-Glucose and d-mannose were at first degraded to d-arabinose, which was subsequently degraded to d-erythrose. While, d-ribose was directly degraded to d-erythrose and d-glyceraldehyde. The degradation processes were selective, and these reactions were shown to proceed via formation of an Fe(III)–monosaccharide complex. The kinetic data and other features of these reactions were also discussed.
Optically Active Anti Head-to-head Coumarin Dimer. A New Agent for the Determination of Enantiomeric Excess of Amines and Alcohols
Authors: Saigo Kazuhiko , Sekimoto Kazuhiro , Yonezawa Noriyuki , Ishii Fumio , Hasegawa Masaki
Published: July 2006

The enantiomeric excess of chiral amines was successfully determined by 1H NMR spectral and/or HPLC analysis of the diastereomeric diamides derived from optically active anti head-to-head coumarin dimer and the amines by lactone-ring-opening reaction without any condensing agent. This procedure also proved to be applicable to chiral alcohols.
Mössbauer Spectroscopic Study of Danalite, Fe4(BeSiO4)3S
Authors: Maeda Yonezo , Takashima Yoshimasa , Ishida Kiyotake
Published: July 2006

The Mössbauer spectra for danalite have been examined in the temperature range 4.2 to 321 K. The strong temperature dependencies of the Mössbauer parameters are explained on the basis of a ligand field at a tetrahedral site for iron.