bluuebunny/crossref_metadata_2025_split huggingface dataset:
Molecular Motion in Ammonium Hydrogendifluoride Studied by Pulsed NMR
Authors: Furukawa Yoshihiro , Kiriyama Hideko 
Published: July 2006

Abstract
The proton and fluorine-19 spin-lattice relaxation times, T1 and T1ρ, in polycrystalline ammonium hydrogendifluoride were measured in the temperature range 142–345 K to elucidate the molecular motion of cation and anion. Below 200 K, the relaxation rates of both nuclei can be accounted for by dipolar interactions modulated via the isotropic reorientation of NH4+ ions. The logT1ρ versus 1/T curves above 200 K exhibit two distinct minima, suggesting that two crystallographically nonequivalent HF2− ions undergo 180°-flips about their two-fold axes with different correlation times. The activation energy of the NH4+ reorientation was determined to be 25.5±1.0 kJ/mol from the T1 data, while those of the 180°-flips were estimated from the T1ρ data to be about 40 and 60 kJ/mol for the two types of anions. These relaxation mechanisms have been confirmed by further experiments on a partially deuterated sample.
The Stereoisomerization of N,N′-Diacyl Derivatives of Indigo
Authors: Omote Yoshimori , Imada Satoshi , Matsuzaki Ryuichi , Fujiki Kiyoko , Nishio Takehiko , Kashima Choji 
Published: July 2006

Abstract
The cis-isomers of N,N′-diacylindigo (e.g., cis-N,N′-diacetyl-, distearoyl-, dibenzoyl-, and bis(3,5-dinitrobenzoyl)-indigo) were found to separate out in a crystalline form from a solution of the corresponding trans-isomer upon irradiation. The kinetics of the cis-to-trans isomerization of these four cis-N,N′-diacylindigos was studied, the relative rates being 7.9, 11.0, 1.0, and 5.1 respectively. Several amines were found to accelerate the cis-to-trans isomerization in the order of: Et2NH&gt;PrNH2&gt;Et3N&gt;i-Pr2NH in the case of cis-N,N′-diacetylindigo and in the order of: Et2NH&gt;i-Pr2NH&gt;PrNH2&gt;Et3N in the case of cis-N,N′-dibenzoylindigo.
A Novel Carbonization of Naphthalene and Other Aromatic Compounds in a Molten Mixture of AlCl3–NaCl–KCl
Authors: Ota Etsuro , Inoue Sadao , Horiguchi Masahiro , Otani Sugio 
Published: July 2006

Abstract
The use of molten salt as the solvent made it possible to carry out the carbonization process throughout in the liquid state. The process proceeded at a lower temperature than conventional ones, resulting in higher yields. The carbon was deposited from the reaction mixture as powder or flakes; it was similar to “raw coke” in its composition. Thus, 12.8 g of naphthalene was treated in a mixed melt (mp 95 °C) of AlCl3, NaCl, and KCl (60:26:14 mol%) at 300 °C for 10 h, yielding 11.3 g of carbon. Anthracene, phenanthrene, substituted naphthalene, and biphenyl also gave carbon in yields 69–99% of the theoretical yields, while N-containing heterocycles hardly reacted at all. The X-ray parameters of the carbons, the d002 spacing and the crystal thickness, Lc, varied with the kind of compound used and with other factors; after heat-treatment at 2800 °C, these values were 3.37–3.52 and 20–700 Å respectively. As the mode of reaction, an acid-catalyzed ionic mechanism was proposed, and the role of hydrogen-disproportionation was discussed.
Bis(N-acetyl-Dl-leucinate)copper(II) Complexes and Their Amine Adducts
Authors: Marcotrigiano G , Menabue L , Morini P , Pellacani G C 
Published: July 2006

Abstract
A compound of the type Cu(AcLeu)2 and its amine adducts of the type Cu(AcLeu)2Bn (AcLeu=N-acetyl-Dl-leucinato ion; n=2 and B=pyridine, 3- and 4-methylpyridine, N-methylpiperazine, morpholine, and piperidine; n=1 and B=1,10-phenanthroline, 2,2′-bipyridyl, piperazine, and pyridazine) were prepared and investigated by means of electronic, infrared and EPR spectroscopy and magnetic moment measurements. The results suggest a tetragonal configuration for the Cu(AcLeu)2 complex and the amine adducts with CuO4 and CuO2N2 chromophores, respectively. For the green Cu(AcLeu)2·pid complex a binuclear configuration similar to that observed for the bis(acetato)copper(II) monohydrate complex is suggested. The amino acid in all the complexes is found to coordinate toward the carboxylato group. In the assignment of the way in which the carboxylato group coordinates, in addition to the difference between their antisymmetric and symmetric stretching frequencies, we also pay special attention to the position of the symmetric stretch, which is directly connected with the oxygen atom linked to the metal ion.
Vibrational Spectra and Rotational Isomerism of 2-Chloro-and 2-Bromoethyl Methyl Sulfides
Authors: Matsuura Hiroatsu , Miyauchi Nobuyuki , Murata Hiromu , Sakakibara Masaaki 
Published: July 2006

Abstract
The Raman and infrared spectra of 2-chloro- and 2-bromoethyl methyl sulfides CH3SCH2CH2X (X=Cl and Br) were measured for the liquid and crystalline solid states. The vibrational frequencies of these molecules were calculated by the use of the force constants transferred from unbranched alkyl sulfides and alkyl halides. The rotational isomerism was studied on the basis of the spectral observations and the calculations, and the following conclusions were obtained. (1) In the crystalline solid state, both the chloride and the bromide take the molecular form with the gauche conformation about the (C)S–C(C) axis and the trans conformation about the (S)C–C(X) axis. (2) In addition to this form (GT), three other forms (TG, GG, and TT) coexist in the liquid state, the GT form being the most stable. (3) The sulfur atom is suggested to lower the energy of the trans conformation of the (S)C–C(X) axis.
Polarized Two-photon Absorption Spectra of Naphthalene in Durene Single Crystal with Two Synchronized Tunable Dye Lasers
Authors: Mikami Naohiko , Hong Hwai-Kwan 
Published: July 2006

Abstract
Polarized two-photon absorption spectra of naphthalene in a single crystal of durene were observed with one and two beams of tunable dye lasers. Diagonal elements of the two-photon transition tensor were determined by one beam experiments with different incident polarizations on different faces of an oriented single crystal. The off-diagonal elements of the two-photon transition tensor were determined with two synchronized beams of different wavelengths and polarizations on the same sample. It was found that most of the vibronic states have large σLL consistent with an overall vibronic Ag symmetry and a long axis polarized 1B2u intermediate state. The intermediate states of the two-photon process of the strongest vibronic origin have been discussed on the basis of the observed values of the two-photon transition tensor elements. The band also has a small but non-vanishing off-diagonal tensor element (σLM). A crystal field perturbation due to reduced site symmetry by a B3g two-photon allowed state is postulated.
Pressure and Solvent Shifts of Charge Transfer Absorption Band of Iodine Complexes
Authors: Sawamura Seiji , Taniguchi Yoshihiro , Suzuki Keizo 
Published: July 2006

Abstract
Absorption spectra of the CT band of I2 complexes were observed in several nonpolar solvents at 1 bar, and in heptane up to 4400 bar. All solvent shifts were red with an increase in (n2−1)/(2n2+1), the refractive index (n) function of solvents, consistent with the solvent shift theory. On the other hand pressure caused a variety of shifts, that is, red shifts in benzene–, toluene–, and mesitylene–I2 complexes, an inversion shift from red to blue in HMB–I2 complex, and blue shifts in Et3N–, n-Pr3N–, and n-Bu3N-I2 complexes, though increase in pressure invariably raises the (n2−1)(2n2+1) value of solvent. The pressure shifts of I2 complexes seem to be interpreted by a sum of two effects. One is the increased polarity of the solvent, which causes a red shift. The other is the decrease in the bond distance between a donor and an acceptor, which contributes to a blue shift in a strong CT complex and to a red shift in a week one. The pressure and solvent shifts of I2 complexes were compared with those of π-donor–TCNE complexes.
Rotational Isomerism in Fluorene Derivatives. III. The Conformation of 9-(9-Fluorenyl)-9-(2-substituted 9-fluorenyl)fluorene Derivatives
Authors: Kajigaeshi Shoji , Fujisaki Shizuo , Aizu Ichishi , Hara Hiroshi 
Published: July 2006

Abstract
The conformations of 9,9-di(9-fluorenyl)fluorene derivatives (1) with substituents at the 2- or 2,7-positions in a terminal fluorene ring were illustrated by the gauche-gauche forms at room temperature. DNMR studies of 1 gave the values of about 85–88 kJ/mol for the free energy of activation (ΔG\eweq) for the restricted rotation around the C(9)–C(9) bonds. The conformation of 9,9-di(9-fluorenyl) fluorene, the parent compound of 1, was also shown to the only gauche-gauche (+sc, +sc or −sc, −sc) form at room temperature.
Studies on 2-Aziridinecarboxylic Acid, II. A Novel Synthesis of Threonine O-Peptide Derivatives via (2S,3S)-3-Methyl-2-aziridinecarboxylic Acid
Authors: Tanaka Takumi , Nakajima Kiichiro , Maeda Toru , Nakamura Akihiro , Hayashi Noboru , Okawa Kenji 
Published: July 2006

Abstract
A new synthesis of threonine O-peptides via the ring opening reaction of aziridine peptide with carboxylic acid has been investigated. Benzyl (2S,3S)-1-[N-(benzyloxycarbonyl)glycyl]-3-methyl-2-aziridinecarbonylglycinate was treated with several N-protected amino acids or dipeptides at their mixed melting point, and the corresponding O-aminoacyl or dipeptidyl esters of l-threonine peptide derivative were obtained in good yields without racemization.
A Synthesis of Neamine
Authors: Harayama Akihiko , Tsuchiya Tsutomu , Umezawa Sumio 
Published: July 2006

Abstract
Neamine and its position isomer were synthesized from 3,4-di-O-acetyl-2-deoxy-2-(p-methoxybenzylidene-amino)-6-O-tosyl-α-d-glucopyranosyl bromide and racemic 5,6(4,5)-O-cyclohexylidene-2-deoxy-1,3-bis-N-(ethoxycarbonyl) streptamine. Influence of the N-protecting groups of 2-deoxystreptamine derivatives for glycosylation was discussed. The unusual Δ[M]TACu value of the position isomer of neamine was ascribed to the interaction between the 6′-amino group and other groups.
Synthesis and Properties of o-Thioquinone Methides Having Ketene Aminal, Ketene Acetal, Ketene Monothioacetal, or Ketene Dithioacetal Group
Authors: Kang Kyung-Tae , Okazaki Renji , Inamoto Naoki 
Published: July 2006

Abstract
Reaction of 1,2-benzodithiole-3-thione with N,N′-dialkyl-1,2-ethanedianiine afforded o-thioquinone methides with a ketene aminal group (6) in high yields. Two similar thionaphthoquinone methides were also prepared. o-Thioquinone methide derived from N,N′-dimethyl-o-phenylenediamine was prepared from 3-chloro-1,2-benzodithiol-3-ylium chloride (10). These compounds were found to exist as a monomer of a considerable betaine nature. Reactions of 6a (N,N′-dimethyl derivative) with dimethyl acetylenedicarboxylate and dibenzoylacetylene led to [4+2] adducts. o-Thioquinone methides with a ketene acetal group were obtained from desulfurization of spiro[1,3-benzodioxole-2,3′-[1,2]benzodithiole] with trimethyl phosphite, which are equilibrated with two kinds of aggregates; one is a dimer and the other is a trimer or a higher oligomer. Reactions of 10 with o-mercaptophenol and 1,2-benzenedithiols gave spiro[1,2-benzodithiole-3,2′-[1,3]benzoxathiole] (29) and spiro[1,2-benzodithiole-3,2′-[1,3]benzodithiole] (39 and 40), respectively. o-Thioquinone methide with a ketene monothioacetal group (30) was prepared by desulfurization of 29. The violet compound 30 is equilibrated with a colorless dimer. This o-thioquinone methide reacted with olefins and an acetylene having electron-withdrawing groups to give 1,4-cycloaddition products. Similar desulfurization of 39 and 40 gave o-thioquinone methides with dithioacetal group. Their properties were very similar to those of o-thioquinone methides with dithioacetal group prepared by the photoreaction of 2 with olefins.
The Crystal and Molecular Structure of Benzanilide
Authors: Kashino Setsuo , Ito Kuniaki , Haisa Masao 
Published: July 2006

Abstract
The crystal structure of benzanilide has been determined from Weissenberg photographs using Cu Kα radiations and refined to an R value of 0.075 for 766 independent reflections. The crystals are monoclinic, space group C2/c, Z=4, with a=24.34(4), b=5.325(3), c=8.012(8) Å, β=107.2(3)°, Dm=1.32 and Dx=1.321 g cm−3. Dihedral angle between the benzene rings is 62.6°, and each benzene ring makes dihedral angle of 31.3 and 31.6° with the plane of amido group as found in Kevlar and Nomex polymers. The molecules related by a b-translation are linked together by N–H…O hydrogen bond [N…O 3.112(6), H…O 2.03 Å, N–H…O 157°] to form a chain along b. The chains are held together primarily by dipole forces of carbonyl groups of the molecules related by inversion centers to form a sheet parallel to the bc plane. The sheets are stacked along a with disorder by van der Waals interactions.
The Modification of Porous Polymer Beads; Use Packing Material in Gas Chromatography
Authors: Takayama Yuzi 
Published: July 2006

Abstract
A new method of the surface modification of a porous polymer has been developed and applied to packing materials for gas chromatography. The porous polymer was coated with a α,β-unsaturated polyester solid polymer, which had a high acid value and which was cross-linked on the porous polymer by polymerization. By using this in gas chromatography, formic acid peaks are completely separated from acetic acid and water peaks without any apparent tailing. This polyester layer was not extractable and could stably be used at 230 °C or higher. If the diallyl phthalate polymer is used instead of the α,β-unsaturated polyester, propionic acid and acrylic acid, which are very diffecult to separate, were resolved. The present method may be applicable to some components of composite materials.
Gas and Solid Phase Photoelectron Spectra of 5,6,11,12-Tetra-phenylnaphthacene (Rubrene)
Authors: Takahashi Takashi , Harada Yoshiya , Sato Naoki , Seki Kazuhiko , Inokuchi Hiroo , Fujisawa Shoji 
Published: July 2006

Abstract
The gas and solid phase UV photoelectron spectra of rubrene were measured. In the molecule there is little conjugation of π-electrons between four substituent phenyl groups and the naphthacene skeleton owing to the effect of the steric hindrance of the phenyl groups. Therefore, the lower IP bands in the gas phase spectrum could be correlated to the π-bands in the photoelectron spectra of benzene and naphthacene. The features of the solid phase spectrum are similar to those of the gas phase one except for a large peak due to inelastically scattered electrons. The polarization energy due to the molecular ion in the solid, the peak to peak difference between the gas and solid phase spectra, was observed to be 0.6 eV, which is about half the polarization energy for naphthacene. This means that rubrene molecules are loosely packed in the solid as a result of the steric hindrance of four phenyl groups.
Interdiffusion of Zinc Ions in Aluminium Cobalt(II) Oxide and Aluminium Nickel(II) Oxide
Authors: Koumoto Kunihito , Matsubara Takao , Takata Masasuke , Yanagida Hiroaki 
Published: July 2006

Abstract
The interdiffusion coefficients \ ildeD of Zn2+ ions in aluminium cobalt(II) oxide (cobalt aluminate) and aluminium nickel(II) oxide (nickel aluminate) were measured. In the former \ ildeD is independent of the concentration of the composition-dependent cation vacancies, while in the latter it decreases with increase in the concentration of cation vacancies. The difference in the distribution of cations and cation vacancies in the spinel lattice has a great effect on the interdiffusion coefficients of Zn2+ ions. The results were interpreted by means of the vacancy mechanism for Co2+ and Ni2+ ions and the interstitial or interstitialcy mechanism for Zn2+ ions. The activation energy is independent of the concentration of Zn2+ ions or cation vacancies; 355 kJ mol−1 for cobalt aluminate and 364 kJ mol−1 for nickel aluminate.
Single Crystal Growth of Zirconium Nitride by Modified Filament-Method
Authors: Sugiyama Kohzo , Watanabe Kunio , Motojima Seiji , Takahashi Yasutaka 
Published: July 2006

Abstract
Single crystals of zirconium nitride (ZrN) have been grown by the modified filament-method from a gas mixture of ZrCl4, N2, H2, and Ar. The cubic crystals grew at 2000–2200 °C with a gas flow ratio 2N2/ZrCl4 of 2–6, and evaporation of ZrN took place above 2400 °C. Linear growth rates along the &lt;100&gt; direction have been measured in terms of sequential micrographs, and attained a maximum of 60–75 μm/min at 2100–2200 °C. The atomic ratio N/Zr of grown crystals increased with an increase of the flow ratio 2N2/ZrCl4, and reached a constant of 0.93 above the flow ratio of 3.
Dimer and Excimer Fluorescence Spectra of Highly Polar Molecules, 3,5-Dialkyl-4-methoxybenzylidenemalononitrile
Authors: Inoue Kenji , Itoh Michiya 
Published: July 2006

Abstract
Dual fluorescence of the ground state dimer of highly polar molecules of 3,5-dialkyl-4-methoxybenzylidenemalononitrile in 3-methylpentane solution at low temperature was investigated by steady-state and nonsecond fluorescence spectroscopies. The dimerization of these compounds was confirmed by concentration dependence of absorption and fluorescence spectra at 77 K. The dimer exhibits dual fluorescence consisting of a short-lived dimer fluorescence and a long-lived excimer fluorescence, while the monomer is almost nonfluorescent at room temperature to 77 K. The excimer formation by an orientational relaxation from the excited state of the dimer was discussed in terms of determination of the activation barrier and the fluorescence polarization.
Electron-transfer Reduction of α-Substituted Ketones and 1,2-Diketones with Benzenethiol Mediated by Iron Polyphthalocyanine
Authors: Inoue Hiroo , Nagata Tadashi , Hata Hiroyuki , Imoto Eiji 
Published: July 2006

Abstract
Iron polyphthalocyanine (Fe-poly PC) has been found to act as an electron-transfer reagent in the reductions of α-substituted ketones, α-bromodeoxybenzoin (1a), 2-bromopropiophenone (1b), α,α-bis(phenylthio)deoxybenzoin (4), and 1,2-diketones, benzil (5) and 4,5-octanedione (8), with benzenethiol. The α-bromo ketones (1a and 1b) have been debrominated to their parent ketones. 4 has been reduced to α-(phenylthio)deoxybenzoin and deoxybenzoin via the cleavage of the carbon-sulfur bond, and 5 and 8 to the corresponding α-hydroxy ketones. The ability of Fe-poly PC to perform these reactions is superior to that of iron phthalocyanine (Fe-PC), particularly those reactions in dry benzene. The catalytic action of Fe-poly PC and Fe-PC becomes evident when methanol or 80 vol % aqueous methanol is used as solvent. Furthermore, the reductions of related compounds by the Fe-poly PC-benzenethiol system are described.
Ligand Effects of Amine Chelates in the Decomposition of 1,2,3,4-Tetrahydro-1-naphthyl Hydroperoxide Catalyzed by Cobalt(II) and Copper(II) Salts
Authors: Yamada Teruaki , Kamiya Yoshio 
Published: July 2006

Abstract
The ligand effects of 2,2′-bipyridine, ethylenediamine, and diethylenetriamine on the rate of decomposition of 1,2,3,4-tetrahydro-1-naphthyl hydroperoxide catalyzed by cobalt(II) decanoate and copper(II) decanoate in chlorobenzene were kinetically studied. The results were compared with the redox potentials measured in nonaqueous media and the spectral data of cobalt(II) and copper(II) complexes. It was found that the catalytic activity of Me(II) decanoate–ethylenediamine, or -diethylenetriamine complex (Me=Co, Cu) becomes maximum at 1/2 the molar ratio of ethylenediamine to Me(II), or at 1/3 that of diethylenetriamine to Me(II), and that further addition of these amines deactivates the catalysts. The activity of copper(II) decanoate increased from k=0 to k=1.4×10−3 s−1 on addition of 2,2′-bipyridine when the molar ratio of 2,2′–bipyridine to copper(II) decanoate was 0–4. No maximum activity was observed in copper(II) decanoate-2,2′-bipyridine system. A large excess of 2,2′-bipyridine, 150 times the quantity of copper(II) salt, did not decrease the decomposition rate in contrast to the case of the cobalt(II) decanoate–2,2′-bipyridine system. The difference in ligand effect of ethylenediamine, diethylenetriamine and 2,2′-bipyridine on cobalt(II) ion and copper(II) ion was discussed on the basis of the properties of these complexes.
Further Study of Methanol Carbonylation Catalyzed by Cobalt, Rhodium, and Iridium Catalysts
Authors: Mizoroki Tsutomu , Matsumoto Toshio , Ozaki Atsumu 
Published: July 2006

Abstract
The effect of iodide ion was examined in methanol carbonylation with use of Co-, Rh-, and Ir-catalysts. Sodium iodide gives no noticeable effect on carbonylation catalyzed by Rh-catalyst to give acetic acid, and retards that catalyzed by Ir-catalyst. Methyl iodide is effective for methanol carbonylation with Co-catalyst in the presence of hydrogen to give mainly acetaldehyde, which is readily hydrogenated to ethanol during the course of carbonylation on addition of a catalytic amount of Ru3(CO)12. Sodium iodide is also effective for acetaldehyde formation, although it strongly retards the hydrogenation of acetaldehyde with Ru-catalyst. The different effect of iodide ion on methanol carbonylation catalyzed by Co-, Rh-, or Ir-catalyst is discussed in terms of neucleophilicity of the active catalyst species.
Synthesis and Reactions of o-Benzothioquinonemethides
Authors: Okazaki Renji , Sunagawa Kazuhiko , Kang Kyung-Tae , Inamoto Naoki 
Published: July 2006

Abstract
Photoreactions of 1,2-benzodithiole-3-thione with olefins (cyclopentene, cyclohexene, cyclooctene, and 2,3-dimethyl-2-butene) afforded deep blue o-thioquinonemethides (4) in high yields. The thione 4 is equilibrated with a colorless head-to-head dimer having an eight-membered ring. The mode of the dimerization has been discussed in comparison with other o-quinonoid compounds. Cycloaddition reactions of 4 with electron-deficient acetylenes and olefins gave rise to [4+2] adducts. It was confirmed that these cycloadditions proceeded stereoselectively as well as regioselectively. Reactions of 4 with diphenylketene, phenyl isocyanate, and phenyl isothiocyanate led to six-membered 1 : 1 adducts. Reduction by hydride reagents has been also described.
Syntheses and Spectral Observation on the Structure of Several 2(1H)-Pyridinethionato Zinc Complexes
Authors: Masaki Mitsuo , Matsunami Satoshi , Kimura Takayuki , Oshima Tokio 
Published: July 2006

Abstract
Although bis[2(1H)-pyridinethionato]zinc (1) is prepared by the reaction of 2(1H)-pyridinethione with zinc chloride in the presence of stoichiometric amount of sodium hydroxide, a similar reaction in the presence of a large excess amount of the base gave μ4-oxo-hexakis-μ-[2(1H)-pyridinethionato-(N,S)]-tetrazinc (2) which is the first example of L6Zn4O (L=ligand) type complexes having heterocyclic thiolato groups as ligands. The complex 2 was also prepared by several routes, which involve hydrolysis of 1 and the reaction of 1 with zinc oxide. In these complexes 2(1H)-pyridinethionato ligand acts as a bidentate or bridging ligand. Attempts to convert bis(4,6-dimethyl-2-pyridylthio)zinc or bis(1-oxido-2-pyridylthio)zinc into a complex of L6Zn4O type were failed. Complexes of L6Zn4O type were also prepared when L were 2-thiazolidinethionato, 5-methyl-2-thiazolidinethionato, and 1-methyl-4-imidazoline-2-thionato.