bluuebunny/crossref_metadata_2025_split huggingface dataset:
Raman Spectra and Electronic Structure of Alkaline Metal Doped Polyacetylene and β-Carotene
Authors: Tanaka Jiro , Saito Yasuyoshi , Shimizu Masaaki , Tanaka Chizuko , Tanaka Masashi 
Published: July 2006

Abstract
Raman spectra of alkaline metal doped polyacetylene were studied at various levels of doping for (CHMy)x, and (CDMy)x, M=Na and K, with y=0–0.18. Several steps in the doping process can be recognized in changes of the Raman spectra; the initial Raman lines remain for y=0–0.06 but change completely into a new pattern at y=0.13. Raman and ESR spectra of alkaline metal doped β-carotene were measured as a model study of the alkaline metal doping of polyacetylene. The correlation of these spectra together with the ab initio SCF MO calculation on model compounds show that a heavily alkaline metal doped polyacetylene chain does not have a uniform bond length structure but is composed of a charged soliton structure connected by a uniform chain. The new Raman bands were assigned based on this structure, implying that a bond alternation still exists in the metallic state of alkaline doped polyacetylene.
Preparation and Stereochemistry of Cobalt(III) Complexes Containing 3,6-Diphenyl-3,6-diphosphaoctane-1,8-diamine or (2S,9S)-4,7-Diphenyl-4,7-diphosphadecane-2,9-diamine, NH2CHRCH2P(C6H5)CH2CH2P(C6H5)CH2CHRNH2 (R=H, CH3)
Authors: Atoh Masamichi , Sugiura Hirofumi , Seki Yoji , Kashiwabara Kazuo , Fujita Junnosuke 
Published: July 2006

Abstract
Nine new cobalt(III) complexes containing 3,6-diphenyl-3,6-diphosphaoctane-1,8-diamine (NPPN), trans-[CoCl2(rac(P)-NPPN)]+, cisα-[Co(L)(rac(P)-NPPN)]n+ (L=en, n=3; L=acac, n=2) and Δ- and Λ-cisα-[Co(L′)(rac(P)-NPPN)]n+ (L′=R-pn, n=3; L′=S-ala or S-pro, n=2), and five new cobalt(III) complexes containing (2S,9S)-4,7-diphenyl-4,7-diphosphadecane-2,9-diamine (SS(C)-NPPN), Δ- and Λ-cisα-[Co(L)(rac(P)SS(C)-NPPN)]n+ (L=en, n=3; L=acac, n=2) and Δ-cisβ-[Co(acac)(meso(P),SS(C)-NPPN)]2+, were prepared, where en, R-pn, acac, S-ala and S-pro denote ethylenediamine, (R)-1,2-propanediamine, 2,4-pentanedionate, (S)-alaninate and (S)-prolinate ions, respectively. Stereochemistries of the complexes and the chiral phosphorus donor atoms were studied on the basis of the absorption, 1H and 13C NMR, and CD spectra. The rac(P)-NPPN and rac(P),SS(C)-NPPN ligands formed selectively either the trans or cisα isomer, while no stable complex was obtained with the meso(P) isomers of NPPN and SS(C)-NPPN except cisβ-[Co(acac)(meso(P),SS(C)-NPPN)]2+ which slowly decomposes in water.
Fluoride Ion-Induced Horner–Emmons Reaction of α-Silylalkylphosphonic Derivatives with Carbonyl Compounds
Authors: Kawashima Takayuki , Ishii Takafumi , Inamoto Naoki 
Published: July 2006

Abstract
Dimethyl α-trimethylsilylbenzylphosphonate was allowed to react with carbonyl compounds in the presence of fluoride ion to give the corresponding olefins in fairly good yields. Use of CsF in tetrahydrofuran gave the best result. On the other hand, dimethyl trimethylsilylmethylphosphonate was allowed to react similarly with benzophenone to afford 1,1-diphenylethylene, dimethyl methylphosphonate, and dimethyl 2,2-diphenylethenylphosphonate. A similar result was obtained by using O,O-diethyl trimethylsilylmethylphosphonothioate. But, reaction of trimethylsilylmethylphosphonic bis(diethylamide) afforded only the protodesilylation product.
Optically Active Polyamides Having (−)-Anti Head-to-Head Coumarin Dimer Component. 2. Chiroptical Property in the Film State
Authors: Chen Yun , Saigo Kazuhiko , Yonezawa Noriyuki , Hasegawa Masaki 
Published: July 2006

Abstract
The chiroptical property of optically active polyamides (3a–i), derived from (−)-anti head-to-head coumarin dimer (1), was investigated by comparing their UV and circular dichroism (CD) spectra with those of the corresponding model diamides (8a–i) in the film state. The result suggests that the polyamides (3a–c,g) derived from acyclic aliphatic diamines, exist in a random conformation due to the flexibility of the diamine components. The polyamides (3d,h), consisting of piperazine, are assumed to be in a rod-like conformation, resulting from their rigid and fixed main chains. The polyamides (3e,f,i), prepared from aromatic diamines, show reversed and split Cotton effects at 270–300 nm in comparison with those of model diamides. This phenomenon is interpreted by the formation of an ordered conformation of macromolecular asymmetry.
The Magnetic Properties of the Ammonium Chloride Adducts of Copper(II) Fluoroacetate and Copper(II) Bromoacetate
Authors: Emori Shuji , Morishita Nobuhide , Muto Yoneichiro 
Published: July 2006

Abstract
Compounds of formula Cu(XCH2COO)2·nACl (A=NH4, CH3NH3, (CH3)2NH2, (CH3)4N and X=F, Br) have been prepared, and characterized by magnetic susceptibility and IR spectroscopy measurements. Factors affecting the magnetic moments of copper(II) salts of monosubstituted alkanoic acids are discussed.
Chemical Studies on the Lichen. I. The Structure of Isolecanoric Acid, a New ortho-Depside Isolated from Parmelia tinctorum Despr.
Authors: Sakurai Atsushi , Goto Yohko 
Published: July 2006

Abstract
A new ortho-depside, isolecanoric acid was isolated from Parmelia tinctorum Despr. and 2-(2,4-dihydroxy-6-methylbenzoyloxy)-4-hydroxy-6-methylbenzoic acid was assigned to this substance from studies on the hydrolysis products and from analyses of the 1H and 13C NMR spectra. This substance is the first ortho-depside isolated from the genus Lichen.
A Facile Preparation of Flavones Using Nonaqueous Cation-Exchange Resin
Authors: Hoshino Yukio , Takeno Noboru 
Published: July 2006

Abstract
Flavone was prepared from 1-(2-hydroxyphenyl)-3-phenyl-1,3-propanedione by using nonaqueous cationexchange resin in a nearly quantitative yield. Of several reaction media, isopropyl alcohol gave the best result. Eight substituted flavones were also synthesized from the corresponding diketones in satisfactory yields.
Crystal Structure of Bis(2,2′-bipyridine)copper(I) Perchlorate
Authors: Munakata Megumu , Kitagawa Susumu , Asahara Akio , Masuda Hideki 
Published: July 2006

Abstract
The crystal structure of the title complex was determined by X-ray diffraction: Orthorhombic, space group C2221, a=20.553(2) Å, b=11.210(1) Å, c=8.980(2) Å, and Z=4. The structure was solved by the direct method and was refined anisotropically by the full-matrix least-squares method: R was 0.062 for 1206 observed reflections. The [Cu(bpy)2]+ cation has a pseudo-tetrahedral arrangemeni (average Cu–N=2.021 Å). The interligand dihedral angle in [Cu(bpy)2]+, 75.2°, differs significantly from that previously reported [Cu(1,10-phenanthroline)2]ClO4 (49.9°).
Reductive Dimerization of Allyl and Benzyl Halides in Pb/n-Bu4NBr–DMF and PbBr2/Al–DMF Systems
Authors: Tanaka Hideo , Yamashita Shiro , Torii Sigeru 
Published: July 2006

Abstract
Reductive dimerization of allyl and benzyl halides has been performed by treatment with Pb/n-Bu4NBr and catalytic PbBr2/Al in N,N-dimethylformamide.
Preparation of Some Lanthanoid Picrates and the Behavior of Their Water of Hydration
Authors: Nakagawa Kazuharu , Amita Kayoko , Mizuno Hifumi , Inoue Yoshihisa , Hakushi Tadao 
Published: July 2006

Abstract
Lanthanoid(III) picrates (Ln=La, Ce, Pr, Nd, Sm, Eu, Gd, Dy, and Yb) were prepared from picric acid and the corresponding lanthanoid carbonates in good yields. Combustion analyses, ICP emission analyses, and UV spectrophotometry have shown that the light lanthanoid picrates, i.e. Ln=La–Gd, are all undecahydrates, while the heavy ones, Dy and Yb, are octahydrates. An examination by TG-DTA has revealed that these hydrates, being fairly stable in air at ambient temperature, are quite labile to give partially or completely dehydrated samples upon drying under vacuum, in a desiccator, and/or at elevated temperatures just above 30°C.
Synthesis of 1,2-Di-O-alkyl-sn-glycero-3-phosphatidylcholine Using 2-Methoxyethoxymethyl and 2-(Trimethylsilyl)ethoxymethyl Protective Groups
Authors: Yamauchi Kiyoshi , Hihara Mitsuyoshi , Kinoshita Masayoshi 
Published: July 2006

Abstract
2-Methoxyethoxymethyl (MEM) and 2-(trimethylsilyl)ethoxymethyl (SEM) groups were used to protect the sn-3-OH of optically active glycerols in the synthesis of 1,2-di-O-octadecyl-sn-glycero-3-phosphatidylcholine. Both MEM and SEM protective groups had advantages of a classical benzyl group by virtue of (i) the facile preparation of 1,2-O-isopropylidene-3-O-(2-methoxyethoxymethyl)-sn-glycerol and its sn-3-O-SEM analog as starting materials and (ii) the rapid demasking of the MEM and SEM moieties in lipid precursors, especially by means of titanium tetrachloride.
Fast Reactions of Organic Anion Radicals with Organic Halides in Hexamethylphosphoric Triamide Studied by Pulse Radiolysis
Authors: Honda Eiji , Tokuda Masao , Yoshida Hiroshi , Ogasawara Masaaki 
Published: July 2006

Abstract
Fast reactions of diethyl fumarate anion radical (DEF−) and fluorenone anion radical (Fl−) with various organic halides (RX) in hexamethylphosphoric triamide have been studied by means of ns pulse radiolysis at room temperature. Reactions of acetophenone anion radical were also studied for comparison. It was found that the reaction rate of Fl− was subject to the steric and resonance effects of R groups of RX in accord with the classical concept of SN2 reactions: the rate constant was reduced by 2 orders of magnitude by the steric effect when R was changed from ethyl to bulky isopropyl or t-butyl, and it was still large by the resonance effect of R even if R was changed from ethyl to an allyl or a benzyl group. While the reaction rate of DEF− was not much affected when R was changed to more bulky groups, the rate constant was correlated to the reduction potential of RX. The results were interpreted in terms of a VB correlation diagram approach or rate-equilibrium relationship within a framework of SN2 reactions.
The Role of COad in the Oxidation of Methanol at a Platinum Electrode in an Acid Solution
Authors: Matsui Hiroshi , Hisano Takeo 
Published: July 2006

Abstract
The role of the adsorbate COad in the oxidation of methanol was studied under a variety of experimental conditions on the basis of the rate-ratio of the path of CO2 formation via COad to the overall oxidation of methanol at a platinum electrode in 0.5 mol dm−3 of H2SO4. The results: (a) At potentials below 0.55 V and with a short time of oxidation, COad inhibited its own formation; (b) at 0.60–0.75 V and with a long time of oxidation, COad was a poison to parallel reactions; (c) at above 0.8 V and at θ1&gt;0.15, the formation of CO2 via COad was predominant, and the COad never hindered parallel reactions. There was no difference between the role of the COad formed from dissolved CO and that of the COad formed from methanol, though, in the absence of dissolved CO, the oxidation of methanol was, for some reason, inhibited at small coverages close to the respective limiting values. When the coverage was larger than about 0.85, COad remarkably inhibited all the parallel reactions in the methanol oxidation.
Studies of the Hydrous Zirconium(IV) Oxide Ion Exchanger. I. Ion-Exchange Properties and Effect of Heat Treatment
Authors: Inoue Yasushi , Yamazaki Hiromichi 
Published: July 2006

Abstract
A satisfactory method was established for synthesizing a hydrous zirconium(IV) oxide ion exchanger; also, its ion-exchange properties and thermal stability were studied. The exchanger was synthesized reproducibly by hydrolyzing a ZrOCl2 solution at pH 9.3 with the addition of NH3 aq. This material was an amphoteric ion exchanger possessing an isoelectric point close to pH 6.5. The order of affinity for the cations was, transition metal&gt; alkaline earth metal&gt;alkali metal. Transition metal ions form a coordinate bond with OH groups in the exchanger. The OH groups, which were easily condensed by a heat treatment, were not restored even when the samples subjected to thermal treatment were immersed in water: Thirty percent of the initial ion-exchange capacity was lost when the exchanger was heat-treated at a temperature as low as 70 °C, and the exchange sites were completely destroyed between 400 and 550 °C.
A Method of Calculation for d.c. Polarographic Catalytic Wave
Authors: Kikuchi Kenji 
Published: July 2006

Abstract
A new numerical method for theoretical analysis of polarographic catalytic current is proposed and applied to well-studied systems to prove that the method is dependable. In this method, a system of partial differential equations of diffusion is transformed to finite-difference form by using Crank–Nicolson difference scheme, and the latter is solved by using both Gauss–Seidel and successive over relaxation methods. Chemical kinetics terms in the diffusion equations is substituted by ones rewritten by three alternative procedures. The method has been applied to a system of copper(II) and hydrogen peroxide. Resulted rate constant of participating chemical reaction agrees with the rate constant obtained from bulk solution experiments. This and other results show that the method is a useful tool for theoretical analysis of catalytic waves.
NAD(P)+–NAD(P)H Model. 62. The Mechanism of the Silica Gel-Catalyzed Reduction with an NAD(P)H Model
Authors: Yasui Shinro , Fujii Masayuki , Nakamura Kaoru , Ohno Atsuyoshi 
Published: July 2006

Abstract
The reduction of diethyl acetylenedicarboxylate, diethyl fumarate, and diethyl maleate as well as several α,β-unsaturated carbonyl compounds by a model of NAD(P)H on silica gel was examined. The order of the reactivity for the reduction was reverse to that of the degree of adsorption of the substrates onto the surface of silica gel. Semiquantitative analysis of the results suggests the possibility that silanol groups on the surface of silica gel act as general acid catalysts in the course of the reduction.
Synthesis and Properties of Cyclohepta[hi]pyrrolo[2,1,5-cd]indolizines
Authors: Noguchi Michihiko , Tamai Ryoichi , Tanigawa Noriyuki , Okumura Hiroyuki , Kajigaeshi Shoji 
Published: July 2006

Abstract
The oxidation of the methylene moiety of 4,5,6,7-tetrahydrocyclohepta[hi]pyrrolo[2,1,5-cd]indolizines with NBS gave 5-bromo-6,7-dihydro- (4) and 5-bromo-cyclohepta[hi]pyrrolo[2,1,5-cd]indolizines. The dehydrobromination of 4 with DBU afforded cyclohepta[hi]pyrrolo[2,1,5-cd]indolizines in good yields. The characteristic electronic features of these cycloheptapyrroloindolizines are discussed on the basis of the MO calculations and the spectroscopic properties.
Infrared Spectra of Nitrogen Adsorbed on Ion-Exchanged ZSM-5 Zeolite
Authors: Yamazaki Tatsuya , Watanuki Isao , Ozawa Sentaro , Ogino Yoshisada 
Published: July 2006

Abstract
Amounts of nitrogen adsorbed by ion-exchanged ZSM-5 zeolites (H+, Li+, Na+, K+, Rb+, and Cs+) and silicalite have been measured under various conditions; pressure=6.7×102–6.7×104 Pa, temperature=196–273 K. IR spectra of adsorbed nitrogen have also been measured at 226 K under various nitrogen pressures (1.3×102–4.0×104 Pa). The adsorption capacity, the specific surface area, and the heat of adsorption have been evaluated from the adsorption data. These quantities coupled with the IR peak shifts observed have revealed that the nitrogen molecule adsorbed on a small and strong cationic site (Li+, Na+) has an orientation in which the longer molecular axis lies in parallel with the direction of the electric field of the cation site. It has also been revealed that the nitrogen molecule adsorbed on a large (K+, Rb+, Cs+) or weak (H+) cationic site takes on no special orientation. The electric field evaluated by analyzing the IR intensity is consistent with the adsorption model obtained.
Micellar Catalytic Effect on the Base Dissociation of Methylamine Studied by the Ultrasonic Absorption Method
Authors: Harada Shoji , Sano Takayuki , Yamashita Teruyo , Yano Hiroshige , Inoue Tadaomi , Yasunaga Tatsuya 
Published: July 2006

Abstract
Micellar catalytic effects on the base dissociation of methylamine have been studied by ultrasonic absorption method. The dissociation constant, the rate constants, and the volume change of the reaction were obtained in the absence and in the presence of SDS. The micellar catalytic effects observed for methylamine was smaller than those for amines of long alkyl chain, which was ascribed to the facts that the former is incorporated into the micellar ionic atmosphere in the concentrated micellar solution while the latters are solubilized into micelles.
A Through Space/Bond Interaction Analysis of the Shape of the Band Structure of Polyacetylene
Authors: Aoki Yuriko , Imamura Akira , Sasaki Takae 
Published: July 2006

Abstract
The band structure of all-trans-polyacetylene is examined by using through space/bond interaction analysis. It is found that the cross-term in the perturbation expansion between two kinds of interactions governs the band shape near the gap: One kind is the interaction within the backbone, and the other is that between the backbone and the side chain. The relationship between the band structure and the symmetry of the interacting orbitals is also discussed.
Studies of the Rate of the Formation of Talc under Hydrothermal Conditions at 400–460 °C
Authors: Muraishi Haruto 
Published: July 2006

Abstract
The rate of the formation of talc from brucite powders with soluble silica under hydrothermal conditions was investigated in the temperature range of 400–460 °C, a range including the equilibrium temperature for the reaction: brucite+serpentine\ightleftarrows2 forsterite+3H2O. Serpentine appeared as an intermediate phase below 415 °C, while above 430 °C forsterite appeared in addition to serpentine. The apparent reaction can be represented as:
(Remark: Graphics omitted.)
The reaction was apparently expressed as a pseudo-first-order reaction. The overall rate of the reaction did not increase with the increase in the temperature. Arrhenius plots of the rate constants for the overall reaction showed a curve with a maximum at about 415 °C and a minimum at about 445 °C which was caused by the alteration of the reaction by the appearance of forsterite at 430 °C.
Rate of Solvent Extraction of Chromium(III) with Acetylacetone into Carbon Tetrachloride
Authors: Sekine Tatsuya , Inaba Kazuho , Morimoto Tatsumu , Aikawa Hidehiko 
Published: July 2006

Abstract
The rate of solvent extraction of chromium(III) in aqueous perchlorate solutions into carbon tetrachloride as the tris(acetylacetonato) complex has been determined. The rate was first order with respect to the acetylacetone concentration and inverse first order with respect to the hydrogen-ion concentration. From this information, the rate-controlling reaction is concluded to be the formation of the first complex in the aqueous phase by a reaction between [Cr(OH)]2+ and HA.
Dynamic NMR as a Nondestructive Method for Determination of Rates of Dissociation. XV. Dissociation of Thioether and Ether Ligands in Tin(IV) and Boron Complexes and Significance of Entropy of Activation Therein
Authors: Oki Michinori , Yamada Yasuhisa 
Published: July 2006

Abstract
The rates of dissociation of thioether ligands which are imbedded in organotin(IV) compounds, such as trichloro[o-(ethylthiomethyl)phenyl]stannane, were determined by the dynamic NMR method. The dynamic processes of the corresponding ether ligands was too fast to detect as the change in line shapes in 1H NMR spectra. All the boron compounds examined, which possessed similar structures to the stannane and were of the boronate type, failed to show dissociation of a thioether or ether ligand due to their large rates of dissociation. The rates of dissociation of a thioether–tribromoboron complex were determined by the same technique. The feature of the activation parameters was that the compounds examined exhibited fairly large positive entropy of activation in accordance with other results that involve dissociation of ionic species into covalent species.
Disulfide Linkages in a Heat-Stable Enterotoxin (STp) Produced by a Porcine Strain of Enterotoxigenic Escherichia coli
Authors: Hidaka Yuji , Kubota Hirokazu , Yoshimura Shoko , Ito Hideaki , Takeda Yoshifumi , Shimonishi Yasutsugu 
Published: July 2006

Abstract
Heat-stable enterotoxins, produced by various enteric bacteria such as enterotoxigenic Escherichia coli, Yersinia enterocolitica, and Vibrio cholerae non-01, have common segments consisting of 13 amino acid residues (T. Takao et al., FEBS Lett., 193, 250 (1985)). These segments have full enterotoxigenic activity and are bound by three intramolecular disulfide bonds. The linkages of these three disulfide bonds in a heat-stable enterotoxin (STp) produced by a porcine strain of enterotoxigenic E. coli were determined to be
(Remark: Graphics omitted.)
by stepwise and selective formation of disulfide bonds using different types of removable protecting groups for Cys residues. These disulfide linkages were identical with those of a heat-stable enterotoxin (STh) produced by a human strain of enterotoxigenic E. coli (Y. Shimonishi et al., FEBS Lett., 215, 165 (1987)).
Equilibrium and Kinetic Studies of the Interaction between Orange I and Bovine Serum Albumin
Authors: Murakami Kiyofumi 
Published: July 2006

Abstract
The interaction between Orange I (sodium 4-[(4-hydroxy-1-naphthalenyl)azo]benzenesulfonate) and bovine serum albumin (BSA) at pH=7.0 and 25 °C has been studied by equilibrium dialysis, spectrophotometry, and the temperature-jump method. Equilibrium dialysis has revealed the existence of sixteen equivalent binding sites with the binding constant of K=9.7×103 M−1. All of them were found to be equivalent also in the sense of spectrophotometry. That is, Orange I interacts with BSA in a typically nonspecific manner. Five relaxations were found by the temperature-jump measurements. These relaxation times, distributed over the time range from 10 μs to 0.1 s, were determined over a wide range of reactant concentrations. The fastest relaxation becomes slow, but the four slower ones become fast, with the increase in the concentration of the free ligand. The data were interpreted by means of a combination of the bimolecular binding processes and the four isomerization modes of BSA. The results were discussed in the light of the role of the configurational adaptability of albumin molecules in the ligand-binding mechanism.
Synthesis, Ion-Exchange Properties, and Analytical Applications of Anilinium Tin(IV) Phosphate
Authors: Singh Dhruv Kumar , Darbari Anjana 
Published: July 2006

Abstract
A new inorganic ion-exchanger anilinium tin(IV) phosphate (ATP) has been synthesized under varying conditions. The effects of mixing ratio of reagents and the pH of the mixture on the properties of the material have been studied. The sample ATP1 has been chosen for detailed studies, such as ion-exchange capacity, chemical and thermal stabilities, chemical composition, pH titration, break-through curve, and IR analysis. Distribution coefficients of 16 metal ions have been studied in water, hydrochloric acid and acetone–hydrochloric acid media. On the basis of Kd values some analytically important separations of metal ions have been achieved on the small columns of anilinium tin(IV) phosphate.
Alkylation of Phenol by C9 and C12 Olefins
Authors: Rajadhyaksha Rajeev Anand , Chaudhari Dilip Devidas 
Published: July 2006

Abstract
Alkylation of phenol by 1-dodecene, propylene tetramer and trimer is investigated using a variety of acid catalysts. The catalytic activity of perfluorinated sulfonic acid resin Nafion-H, the recently described ‘sulfate treated’ zirconia and trifluoromethanesulfonic acid is compared with that of cation exchange resin (CER) catalyst which is commonly employed in industrial practice. The activity of zirconia is observed to be comparable to CER and Nafion-H. In view of its low cost and higher thermal and structural stability, this catalyst shows considerable promise for practical application.