bluuebunny/crossref_metadata_2025_split huggingface dataset:
Preparation, Stereochemistry, and Kinetics of Isomerization and Racemization of Bis(2,2′-bipyridine N,N′-dioxide)chromium(III) Complexes Containing an Oxalate or Malonate Ion
Authors: Kanno Hideaki , Tomita Masanori , Utsuno Shunji , Fujita Junnosuke 
Published: July 2006

Abstract
Two new chromium(III) complexes of the type, [Cr(L)(bpdo)2]+ (L = oxalate (ox2−) or malonate (mal2−) ion), where bpdo denotes 2,2′-bipyridine N,N′-dioxide, were prepared and resolved into a pair of enantiomers by use of Ag2[Sb2{(+)589-tartrate}2]. The perchlorates of these complexes were found to crystallize in the lel2 (Δ(λλ), Λ(δδ)) form. Upon dissolution in water, the complexes isomerized to the lel·ob (Δ(λδ), Λ(δλ)) form with a rapid change in absorption spectra, and then racemized (Δ Λ). Rates of the isomerization and racemization at 25 °C were 7.65 × 10−3 s−1 and 2.20 × 10−3 s−1, respectively for the ox complex, and 4.95 × 10−3 s−1 and 6.42 × 10−5 s−1 for the mal one. These rates were independent of concentrations of H+ and the free bpdo ligand, indicating an intramolecular mechanism for these reactions. The faster reactions of the ox complex than those of the mal one may be attributed to the steric effect due to the less crowded structure of the ox complex.
Regioselective Hydrogenation of Unsaturated Compounds Using Platinum–Zeolite Coupled with Organosilicon Alkoxide by CVD Method
Authors: Kuno Hideyuki , Shibagaki Makoto , Takahashi Kyoko , Honda Ichiro , Matsushita Hajime 
Published: July 2006

Abstract
The regioselective hydrogenation of unsaturated compounds was carried out by catalysis with platinum-zeolite coupled with an organosilicon alkoxide using a chemical vapor deposition method (CVD-modified catalyst). In hydrogenation of a mixture of 1-nonene and trans-4-nonene by this catalyst, the reaction rate of 1-nonene was much greater than that of trans-4-nonene. In particular, when diphenyldiethoxysilane was used as the coupling reagent on the platinum–zeolite, excellent selectivity was produced. Further, it was elucidated that the terminal carbon–carbon double bonds are preferentially hydrogenated in the case of some compounds possessing more than one carbon–carbon double bond.
Photochromism of Heterocyclic Fulgides
Authors: Tomoda Akihiko , Kaneko Akira , Tsuboi Hideki , Matsushima Ryouka 
Published: July 2006

Abstract
Aiming at practical uses of photochromic compounds as data-storage media, electron-donating (e.g. p-dimethylaminophenyl) and conjugate chain (e.g. p-dimethylaminostyryl) substituted heterocyclic fulgides, e.g. 2-[1-(2-substituted 5-methyl-4-oxazolyl)ethylidene]-3-isopropylidenesuccinic anhydride and 2-[1-(5-substituted 2-methyl-3-thienyl)ethylidene or methlyene]-3-isopropylidenesuccinic anhydride, were prepared. The effect on photochromic performance was also investigated; it was clarified that substituents had effects on the red-shift and a significant increase in the color intensity of a colored form. However, the rate of the discoloration reaction was also affected, depressed, by the substituent.
1 : 1 Adduct Ion Formation of Simple Carbohydrate Derivatives with Cations Using FAB Mass Spectrometry. Comparison of O-Acetyl, N-Butyl, and O-Methyl Modifications
Authors: Sawada Masami , Shizuma Motohiro , Takai Yoshio , Yamada Hitoshi , Tanaka Takanori , Okumura Yasuo , Hidaka Yukio , Hanafusa Terukiyo , Takahashi Shigetoshi 
Published: July 2006

Abstract
The 1 : 1 adduct ion formation between a series of per-O-acetylated aldopyranoses (family 1) or N-butylated glycosylamines (family 2) and an organic/metallic cation (n-C8H17NH3+/K+ or Li+) has been examined using quantitative FAB mass Spectrometry. The per-O-acetyl modifications dramatically lead to negated selectivity of the carbohydrates toward the cation which has been clearly observed in per-O-methyl modifications. On the other hand, the mono-N-butyl modifications provide a similar selectivity pattern to mono-O-methyl ones. These results are understood on the basis of electronic and structural considerations.
Hydrosilylation of 1,4-Bis(trimethylsilyl)butadiyne and Silyl-Substituted Butenynes
Authors: Kusumoto Tetsuo , Ando Kenji , Hiyama Tamejiro 
Published: July 2006

Abstract
Hydrosilylation of 1,4-bis(trimethylsilyl)butadiyne using various hydridosilanes and Pt(IV), Pt(0), Rh(I) or Pd catalyst gave, depending on catalyst and hydridosilane, 1,1,3,4-tetrasilyl-substituted 1,3-butadienes or 1,1,3,4-tetrasilyl-substitued 1,2-butadienes. Formation of the 1,2-butadienes was proved to be attributable to second hydrosilylation of primary products 1,2,4-trisilyl-1-buten-3-ynes. For the second hydrosilylation a mechanism was proposed that involves silylmetalation induced through a metalacyclopropene intermediate.
Electric Field Orientation of Ionizable Polymers with Three Different Electric Dipole Moments. I. New Orientation Function and the Steady-State Electric Birefringence of Poly(l-α-glutamic acid) in Methanolic and Aqueous Solutions
Authors: Yamaoka Kiwamu , Kimura Manabu , Okada Mutsuo 
Published: July 2006

Abstract
In order to explain the field strength dependence of the steady-state electric birefringence of ionized poly(l-α-glutamic acid), (Glu)n, in solutions, a new orientation function, Φ(β,ρs,ρ,γ′), was derived on the basis of the permanent dipole, saturable and unsaturable induced dipole (PD–SUSID) moment mechanism. This concept of field orientation is new in that the induced electric moment consists of two parts: One is the saturable induced moment (ΔσE), which transforms to the permanentlike moment (ΔσE0) at the critical field (E0), and the other is the unsaturable induced moment (Δα′E) at any electric fields (E). Some novel features of Φ(β,ρs,ρ,γ′), were graphically illustrated. Comparisons were made between theoretical curves and the birefringence data experimentally measured at 20 °C up to 24 kV cm−1 for helical (Glu)n in pure methanol and in methanol–water (95 : 5 vol%) as well as for coiled (Glu)n in aqueous solutions (pH 6.9 and 8.0). The degree of dissociation was 0.041 in the former solutions and close to unity in the latter solutions. The field orientation was found to be mostly due to the permanent moment for unionized or slightly ionized (Glu)n, but dominantly due to the saturable induced moment for fully ionized (Glu)n. Appropriate procedures are discussed for estimating the intrinsic birefringence at infinitely high fields.
X-Ray Photoelectron Study of the Methane Interaction with LaCoO3
Authors: Tabata Kenji , Kohiki Shigemi 
Published: July 2006

Abstract
The interaction of CH4 with LaCoO3 has been studied at room temperature with the use of an X-ray photoelectron spectroscopy (XPS) analyzer. CH4 dissociated on the surface of LaCoO3, and new carbonaceous products were detected at 104 langmuir exposure on the spectra for C1s. Since the intensities of the adsorbed oxygen on the spectra for O1s gradually decreased in proportion to the increase in the amount of CH4 exposure, methane reacted with adsorbed oxygen of LaCoO3 at room temperature in an XPS analyzer.
Studies on Nickel-Containing Ziegler-Type Catalysts. I. New Catalysts for High-cis-1,4-polybutadiene
Authors: Sato Hiroshi , Yagi Yoshiharu 
Published: July 2006

Abstract
Some organic halogenides were found to induce a catalytic activity in a nickel naphthenate (Ni(naph)2)/AlEt3 system for the stereospecific polymerization of butadiene to a high cis-1,4 microstructure. These new activators were fluorinated carbonyl (or carboxyl) compounds, halogenated phenols or halogenated hydroquinones. These compounds were assumed to induce polymerization activity through the formation of Lewis acidic components with AlEt3. For this catalyst, H2O acted as an efficient molecular weight promoter.
(Trifluoromethyl)benzene was found to promote the activity of a catalytic system: Ni(naph)2/AlEt3/organic halides. AlEt2F was found to be formed between AlEt3 and (trifluoromethyl)benzene. Finally, a simple system was found to be an efficient catalyst, Ni(naph)2/AlEt2F/H2O, for which chlorinated phenols acted as an effective molecular weight regulator.
Studies on Nickel-Containing Ziegler-Type Catalysts. II. Low Molecular Weight (Liquid) Poly(diene)s with 1,4-Microstructure
Authors: Sato Hiroshi , Yasui Seimei 
Published: July 2006

Abstract
Liquid polybutadiene and liquid polyisoprene, which are usefull precursor for coatings, plastisizers or lubricants, were effectively synthesized by polymerizing butadiene and isoprene, respectively, in the presense of a nickel-containing Ziegler-type catalyst utilizing a lower α-olefin or molecular hydrogen as a molecular weight regulator. The catalyst consists of four components; nickel naphthenate (Ni(naph)2)/AlEt3/(trichloromethyl)benzene(BTC)/triphenyl phosphite (TPP) or triphenylphosphine (TPN). The microstructure of these liquid polymers is mainly 1,4-(cis/trans), which is advantageous for their reactivity and the rheological properties. The hydrogenated low molecular weight liquid polyisoprene exhibited very similar properties to those of squalane, which is a hydrogenated product of natural squalene.
Kinetics of Electroless Copper Plating in the Presence of Excess Triethanolamine
Authors: Kondo Koji , Ishida Nobumasa , Ishikawa Junji , Irie Masahiro 
Published: July 2006

Abstract
The electroless copper plating rate dependence on the various ligands, such as ethylenediaminetetraacetic acid (EDTA), nitrilotriacetic acid (NTA), N,N,N′,N′-tetrakis(2-hydroxypropyl)-ethylenediamine (HPA), N,N,N′,N′-tetrakis(2-hydroxyethyl)-ethylenediamine (HEA), triethanolamine (TEA), and triisopropanolamine (TIPA), were examined. TEA solution plating rate was the fastest of all ligands, the maximum rate being over 20 times faster than the current rate observed in the EDTA system. In order to reveal the rate dependence on the ligand, the adsorption equilibrium constants for Cu(II)-ligand complex onto the adsorbed ligand and the maximum deposition rates were determined based on the plating model previously proposed. The dependence was explained using the ligand adsorption equilibrium constant; (K1) onto the reactive surface; (K2) onto the adsorbed complexes and (K3) the complex adsorption equilibrium constant.
Genesis of Highly Active Cobalt Sulfide Catalyst for Hydrogenation and Isomerization: Effect of the Calcination Temperature of Precursor Cobalt Oxide upon the Catalytic Properties of Cobalt Sulfide
Authors: Okamoto Yasuaki , Nagata Kozo , Imanaka Toshinobu , Inamura Kazuhiro , Takyu Toshiyuki 
Published: July 2006

Abstract
It was found that the catalytic activities and selectivities of cobalt sulfide catalysts are significantly affected by the calcination temperature of precursor cobalt oxide for the hydrogenation of butadiene and the isomerization of 1-butene. When cobalt sulfide was prepared from cobalt oxide calcined at 1473–1573 K, the specific activities per surface area of the sulfide were enhanced by 30–40 times those of cobalt sulfide prepared from cobalt oxide calcined at a conventional temperature, 573–973 K. The reaction selectivities were also strongly modified by the calcination temperature of precursor oxide. It is suggested that two different types of active sites are formed on cobalt sulfide, depending on the calcination temperature of the precursor. On the basis of XPS, XRD, SEM, and NO adsorption techniques, it is concluded that the particle size of the precursor cobalt oxide and sulfiding conditions determine the surface sulfur content and hence the catalytic properties of the sulfide catalysts. The sulfidation mechanism of cobalt oxide and active site models are proposed.
Photodissociation of Highly-Excited Triplet State of Benzophenone Studied by a Time-Resolved Thermal Lensing Technique
Authors: Kajii Yoshizumi , Suzuki Tadashi , Takatori Yoshiki , Shibuya Kazuhiko , Obi Kinichi 
Published: July 2006

Abstract
Two-step photo-absorption processes of benzophenone and photodissociation of the highly-excited triplet state have been investigated in solution by the time-resolved thermal lensing technique. Two-step absorption processes at 308 nm are found to be composed of the first S1 ← S0 absorption followed by a rapid intersystem crossing to T1 and the second Tn ← T1 absorption. The quantitative analysis of time-resolved thermal lensing signals leads to an unexpected result that only 51 ± 6 % of the photon energy absorbed by the molecule in T1 has been detected as the heat released back to the system. This observation could be explained by a model that a fast photodissociation of benzophenone takes place from Tn. The chemical evidence and energy consideration support the dissociation into two phenyl radicals and a carbon monoxide molecule.
N-Hydroxy Amides. X. Synthesis of a Nonapeptide with an Ala-(HO)Gly-Ala Sequence and Its Spectral and Iron(III) Holding Properties
Authors: Akiyama Masayasu , Katoh Akira , Iijima Masakazu , Takagi Takeshi , Natori Keiko , Kojima Tomoaki 
Published: July 2006

Abstract
A nonapeptide with an Ala–(HO)Gly–Ala sequence has been synthesized via condensation of appropriately protected tripeptide units. 1H NMR and CD spectral data indicate that the nonapeptide has a disordered structure in DMSO and water. The peptide forms a 1 : 3 complex of iron(III) with hydroxamate groups at neutral pH when mixed with an aqueous iron(III) solution. The complex shows λmax at 410 nm with an ε of 2160 at pH 7. Alanine residues influence the hydroxamate groups to produce a chiral complex, the CD spectrum of which reveals bands at 355 nm (Δε+0.8) and 435 nm (Δε−1.8), showing a preference for the Δ-configuration around the iron.
Formation and Reaction of Carbonyl Ylides. Reactions of 1-Methoxy-2-benzopyrylium-4-olate with Isothiocyanates
Authors: Ibata Toshikazu , Nakano Hirofumi , Tamura Hatsue 
Published: July 2006

Abstract
The 1,3-dipolar cycloaddition of 1-methoxy-2-benzopyrylium-4-olate (2) generated by Cu(acac)2-catalyzed decomposition of methyl 2-diazoacetylbenzoate with various aryl isothiocyanates and methyl isothiocyanate gave 2 : 1-, 3 : 1-, 4 : 1-, and 5 : 1-adducts without affording 1 : 1-adduct. The first cycloaddition of 2 occurs on the C=N double bond of isothiocyanate. The cycloadditions of the following steps, such as second, third, fourth, and fifth cycloadditions, proceed on C=O group of the cycloadducts of each previous steps. The molecular structure of the 2 : 1-adduct of 2 with phenyl isothiocyanate was determined by means of X-ray crystallography. Colorless crystals of the adduct are monoclinic with the space group P21/a, and with the unit-cell dimensions of a = 12.619 (4), b = 16.432 (4), c = 11.238 (2) Å, β = 97.39 (1)°, and Z = 4. The structure was calculated by direct methods (MULTAN 80) and refined by block-diagonal least-squares methods. All hydrogen atoms were revealed by a difference-Fourier synthesis, and further least-squares refinements gave the final R value of 0.046.
Manganese(II and III)-Mediated Synthesis of Cyclic Peroxides from Alkenes, Active Methylene Compounds, and Molecular Oxygen
Authors: Qian Chang-Yi , Yamada Takashi , Nishino Hiroshi , Kurosawa Kazu 
Published: July 2006

Abstract
The reaction of 1,1-diphenylethene, 1,1-bis(4-chlorophenyl)ethene, 1,1-bis(4-methylphenyl)ethene, 1,1-bis(4-methoxyphenyl)ethene, and 1,1-bis(4-fluorophenyl)ethene with 2-methyl-1,3-cyclohexanedione, 2-methyl-1,3-cyclopentanedione, 2-acetylcyclohexanone, ethyl 2-acetyl-3-oxobutanoate, 3-methyl-2,4-pentanedione, 1,3-cyclohexanedione, and 2,4-pentanedione in the presence of Mn(OAc)2 and molecular oxygen yielded the corresponding cyclic peroxides in moderate-to-good yields. Similar reaction of 1,1-disubstituted alkenes with 1,3-cyclopentanedione in the presence of Mn(OAc)3 and molecular oxygen gave 2,2,9,9-tetraphenyloctahydro-3,4,7,8-tetraoxabenz[c]indene-4a,6a-diols. Acid-catalyzed decomposition of 4-acetyl-6,6-diaryl-3-methyl-1,2-dioxan-3-ols yielded 3-acetyl-5-aryl-2-methylfurans in moderate yields. Treatment of the 4-acetyl-6,6-diaryl-3-methyl-1,2-dioxan-3-ols with alkali gave 6,6-diaryl-3-methyl-1,2-dioxan-3-ols which gave 1-aryl-1,4-pentanediones upon treatment with hydrochloric acid in acetic acid. The synthetic utility and mechanisms of the reactions are discussed.
Reactions of (E)-2-Iodo-1-tosyl-1-alkenes as Useful Synthetic Intermediates
Authors: Iwata Noriyoshi , Morioka Tetsuro , Kobayashi Toshifumi , Asada Takahiro , Kinoshita Hideki , Inomata Katsuhiko 
Published: July 2006

Abstract
(E)-2-Iodo-1-tosyl-1-alkenes readily available by iodosulfonization of 1-alkynes were found to be useful synthons for the regio- and/or stereoselective preparation of 1-tosyl-1-alkynes, 1-tosyl-2-alkynes, (Z)-vinyl and (Z)-allyl sulfones, β-tosyl enamines, α-tosyl ketones, α-tosyl aldehyde acetal, and β-disubstituted vinyl sulfones.
Selective Preparation of 1-Halo-2,6-dimethoxybenzenes from Bis(2,6-dimethoxyphenyl)dimethyltin
Authors: Wada Masanori , Wakamori Hiroyuki , Hiraiwa Akira , Erabi Tatsuo 
Published: July 2006

Abstract
With a hope to explore a facile method for preparation of 1-halo-2,6-dimethoxybenzenes, bis(2,6-dimethoxyphenyl)dimethyltin was prepared from 1,3-dimethoxybenzene, butyllithium, and dimethyltin dichloride or dimethyltin sulfide. The compound reacted with N-chlorosuccinimide and with N-bromosuccinimide in methanol to afford 1-chloro-2,6-dimethoxybenzene and 1-bromo-2,6-dimethoxybenezene, respectively. The dimethyltin by-product was obtained either as dimethyltin oxide or as dimethyltin sulfide. A reaction with iodine was performed in the presence of potassium sulfide to afford 1-iodo-2,6-dimethoxybenzene and dimethyltin sulfide. Preparation and reactions of analogous organosilanes also are described.
Acid-Promoted Reactions of Schiff’s Bases with Ketene Dithioacetal, Vinyl Sulfides, and 1,2-Propadienyl Sulfides
Authors: Narasaka Koichi , Shibata Takanori , Hayashi Yujiro 
Published: July 2006

Abstract
Several types of addition reactions proceed between Schiff’s bases and olefinic nucleophiles containing an alkylthio substituent. Ketene dithioacetal or 2-(methylthio)allylsilane reacts with Schiff’s bases in the presence of trifluoromethanesulfonic acid to afford β-amino acid equivalents or homoallylic amines, respectively. On the other hand, ene reaction proceeds between 1-alkyl-1,2-propadienyl sulfides and Schiff’s bases by treatment with AlCl3, giving 1,3-dienes.
Two Variants of the Topological Index and the Relations between Them
Authors: Gutman Ivan , Hosoya Haruo , Urakovic Gordana , Ristic Lidija 
Published: July 2006

Abstract
The two topological indices σ (recently proposed by Merrifield and Simmons) and Z (put forward by one of the present authors, Bull. Chem. Soc. Jpn., 44, 2332 (1971)) are shown to be both conceptually and numerically related. For alkanes, a linear correlation exists between ln σ and ln Z. For unbranched catacondensed benzenoid hydrocarbons σ and Z are linearly correlated. In any case σ and Z exhibit a reverse dependency on molecular structures: structural transformations having an increasing effect on Z decrease σ and vice versa.
Reactions of Water and Dinitrogen Monoxide Adsorbed on Cation-Exchanged Zeolite with Excess Electrons Generated by Gamma-Radiation
Authors: Aoki Masayoshi , Nakayama Takeshi , Nakazato Chiyoko , Masuda Takahiro 
Published: July 2006

Abstract
Hydrogen formation from water and nitrogen formation from dinitrogen monoxide adsorbed on a zeolite during gamma-irradiation have been studied in order to clarify the role of the metal cation contained in the zeolite and the effect of the pore size; Molecular Sieve 4A, 5A, 13X, and cation-exchanged 13X were used for that purpose. The hydrogen yield from water was observed to increase with increasing amount of adsorbed water. The dependence of G(H2) on the amount of adsorbed water was affected by the exchange of metal cations and the pore size of the zeolite. For nitrogen formation from dinitrogen monoxide in cation-exchanged 13X, the saturation behavior of G(N2) could be roughly classified into two categories, namely one approaching ca. 3 and the other around 6. The results indicate that the metal cation participates in the reaction of an excess electron with an adsorbed water molecule, at least in the range of small amounts of water.
Size of Micelles of 1-Dodecylpyridinium Chloride in Aqueous NaCl Solutions
Authors: Fujio Katsuhiko , Ikeda Shoichi 
Published: July 2006

Abstract
Static light scattering has been measured on aqueous NaCl solutions of 1-dodecylpyridinium chloride over the NaCl concentrations from 0 to 4.00 M at 25 °C, and the micelle molecular weight has been estimated by means of the Debye equation. In aqueous solution the molecular weight is as small as 5280, corresponding to the aggregation number, 18.6. With increasing NaCl concentration up to 0.05 M the molecular weight increases sharply, reaching 12350. The small micelles would not be so compact as the common spherical micelles but would be porous except for their core. With increasing NaCl concentration beyond 0.05 M the micelle molecular weight increases only gradually, similar to growth of the common spherical micelles, and reaches 20410 in 4.00 M NaCl.
Kinetic Studies on the Terminal Pyridine Exchange Reactions of Some Oxo-Acetate Bridged Trinuclear Ruthenium Complexes. Influence of the Metal Oxidation State and Non-Leaving Terminal Ligand (CO)
Authors: Abe Masaaki , Sasaki Yoichi , Nagasawa Akira , Ito Tasuku 
Published: July 2006

Abstract
Substitution reactions of py-d5 for the terminal pyridines of the three triruthenium complexes, [Ru3(μ3-O)(μ-CH3COO)6(py)3]+ (1) (Ru3(III, III, III)), Ru3(μ3-O)(μ-CH3COO)6(py)3 (2) (Ru3(II, III, III)), and Ru3(μ3-O)(μ-CH3COO)6(CO)(py)2 (3) (Ru3(II, III, III)), have been studied in CD3CN by following the change in 1H NMR spectra. The rates are practically independent of [py-d5] (0.05–1.0 mol dm−3). The first-order rate constants are 3 × 10−5 s−1 at 55 °C (ΔH≠ = 123 ± 6 kJ mol−1, ΔS≠ = +41 ± 19 J K−1 mol−1), 5.9 × 10−4 s−1 at 50 °C (ΔH≠ = 122 ± 14 kJ mol−1, ΔS≠ = +69 ± 44 J K−1 mol−1), and 3 × 10−5 s−1 at 55 °C (ΔH≠ = 126 ± 9 kJ mol−1, ΔS≠ = +52 ± 27 J K−1 mol−1) for 1, 2, and 3, respectively. Rate constants appear to depend on the apparent oxidation state of the metal center. While the three Ru ions in 2 are equivalent and each ion has average oxidation number +2(2/3), Ru ions with coordinated py in 3 are in +3 oxidation state as the +2 oxidation state is localized at carbonyl-Ru ion. A dissociative mechanism is proposed for these reactions on the basis of the absence of [py-d5]-dependence, the activation parameters, and the comparison of the rate constants with those of the substitution of methanol-d4 for the terminal water ligands in [Ru3(μ3-O)(μ-CH3COO)6(H2O)3]+.