bluuebunny/crossref_metadata_2025 huggingface dataset:
Palladium Catalyzed Coupling Reaction of Acylchromate Complexes and Allylic Bromides
Authors: Sakurai Hidehiro , Tanabe Katsuhiko , Narasaka Koichi
Published: May 2003

A cross-coupling reaction between acylchromate complexes and allylic bromides takes place under CO atmosphere in the presence of a catalytic amount of Pd(PPh3)4 to afford the corresponding allylic ketones in good yield. The same reaction also proceeds by adding RNC under argon atmosphere in place of CO atmosphere. Thus, the acylchromate complex works as a good acyl donor for Pd catalyzed acylation reaction.
Propagating Radicals in Photo-Initiated Polymerization as Detected by Time-Resolved CW- and FT-ESR Spectroscopy
Authors: Mizuta Yukio , Morishita Norio , Kuwata Keiji
Published: May 2003

The primary propagating radicals in photo-initiated polymerization of isoprene and MMA were directly detected and assigned for the first time by use of time-resolved ESR spectroscopy. Based on the kinetic analysis including the spin-lattice relaxation, the rate constant of the formation and the relaxation time were determined for the primary propagating radicals by simulating time-profile of the FT-ESR intensity.
An ESR Study of a Tetrasilaspirobiindane Anion Radical. Stereoelectronic Electron-Accepting Effects of Trialkylsilyl Groups
Authors: Setaka Wataru , Kabuto Chizuko , Kira Mitsuo
Published: May 2003

ESR spectra of a tetrasilaspirobiindane anion radical (1−) showed a doublet of doublet hfs pattern at low temperatures and significant line-width alternation, indicating that there is remarkable difference in the electron-accepting effects between two silyl substituents at the benzene ring with the unpaired electron due to the ring conformation.
Photo-induced DNA Cleavage by Water-soluble Cationic Fullerene Derivatives
Authors: Takenaka Shigeori , Yamashita Kenichi , Takagi Makoto , Hatta Taizo , Tsuge Otohiko
Published: May 2003

Fullerene derivatives 1a–c cleaved double stranded DNA under photo-irradiation through the action of singlet oxygen generated by the reaction of the photo-excited fullerenes with oxygen. The photolysis in conventional aqueous solution was more effective than that in the presence of PVP or γ-cyclodextrin.
Development of Catalyst-Membrane System for Oxidative Coupling of Methane by Water
Authors: Terai Takami , Li Xiaohong , Tomishige Keiichi , Fujimoto Kaoru
Published: May 2003

It has been reported that SrTi0.4Mg0.6O3−δ catalyst showed good performance for the oxidative coupling of methane by using water as an oxidant (2CH4 + *H2O → C2H6 + *H2 + H2O). But the yield of C2 hydrocarbons in this reaction was almost constant at W/F=5-20 gh/mol. SrCe0.95Yb0.05O3−α tube-type membrane was utilized to remove H2 selectively in coupling of methane to C2 hydrocarbons from CH4 and water. When SrTi0.4Mg0.6O3−δ catalyst was used in this catalyst-membrane system, the yield of C2 hydrocarbons was drastically promoted.
Synthesis and Properties of Novel Ru-Ni and Ru-Cu Dinuclear Complexes
Authors: Komatsuzaki Nobuko , Himeda Yuichiro , Goto Midori , Kasuga Kazuyuki , Sugihara Hideki , Arakawa Hironori
Published: May 2003

Novel Ru-Ni and Ru-Cu dinuclear complexes, in which Ru(bpy)22+ (bpy=2,2′-bipyridine) and Ni- or Cu-Schiff base unit fused together, were synthesized. The molecular structure of Ru-Ni dinuclear complex was determined by an X-ray crystal structure analysis. Photochemical studies on these complexes showed that the excited state of the Ru(bpy)22+ moiety in the dinuclear complexes was quenched by intramolecularly attached metal-Schiff base unit.
Photoinduced Intramolecular Proton Transfer and Intermolecular Hydrogen-Atom Abstraction of 1-Piperidinoantraquinone (PAQ)
Authors: Nakayama Toshihiro , Nagai Nobuaki , Torii Yukiyoshi , Hamanoue Kumao
Published: May 2003

The lowest excited singlet and triplet states of PAQ give rise to formation of the N-ylide compound at 77 K and the reduced compound at room temperature, respectively. In the latter case, however, indirect population of the lowest excited triplet state from a higher excited singlet state (through a higher excited triplet state) is very important.
Synthesis and Gas Occlusion of New Micropore Substance Rhodium(II) Carboxylates Bridged by Pyrazine
Authors: Mori Wasuke , Hoshino Hiroyuki , Nishimoto Yuko , Takamizawa Satoshi
Published: May 2003

Rhodium(II) carboxylates bridged by pyrazine occlude a large amount of N2 gas, reversibly. The maximum amounts of the occluded N2 gas were 1.8, 1.1, 0.8, 0.6, 0.2, 0.2, 0.5, and 0.6 mol per one mole of rhodium(II) salt with benzoate, o-hydroxybenzoate, m-hydroxybenzoate, p-hydroxybenzoate, o-toluate, m-toluate and p-toluate, respectively, indicating the presence of a large number of micropores in these rhodium(II) carboxylates.

The porous structure which is formed by self-assembly of linear rhodium(II) carboxylates–pyrazine was deduced from the magnetic susceptibilities and by analogy to the structure of copper(II) dicarboxylates which show similar gas-occlusion behavior.
New Photogeneration System of Dihydronicotinamide and Viologen Radical Using Ru(bpy)32+
Authors: Suzuki Masahiro , Kimura Mutsumi , Hanabusa Kenji , Shirai Hirofusa
Published: May 2003

Visible light irradiation (λ > 440 nm) on a methanol solution containing Ru(bpy)32+ and nicotinamide covalently bound to viologen produces both dihydronicotinamide and viologen radical.
A Novel Versatility of Catalase I as a Dioxygenase for Indole-ring-opening Dioxygenation
Authors: Sagawa Takashi , Yomo Tetsuya , Tsugawa Shin-ichi , Takeda Yuka , Ihara Hirotaka , Mitamura Elizabeth Ko , Urabe Itaru , Ohkubo Katsutoshi
Published: May 2003

Catalase I (wild type) from Bacillus stearothermophilus, which was found to have catalase activity, catalyzed dioxygen-inserted indole-ring opening reaction of methyl N-acetyl L-tryptophanate as tryptophan 2,3-dioxygenase (TDO) model in the presence of Na2S2O4. Heme-reconstruction with protoporphyrin IX manganese(III) chloride (MnClPP) via annealing was examined and the reconstituted MnClPP-catalase I also revealed dioxygenolytic behaviour with higher TDO activity and higher selectivity than the catalase I (wild type).
Active Co/SiO2 Catalysts Prepared from Mixing Precursors for Slurry Phase Fischer-Tropsch Synthesis
Authors: Sun Shouli , Fan Li , Fujimoto Kaoru
Published: May 2003

The catalysts prepared by mixing impregnation of cobalt (II) nitrate and cobalt (II) acetate displayed high activity. X-ray diffraction indicated that highly dispersed cobalt metal was the main active site on the catalyst prepared by mixing impregnation method. The metal reduced from cobalt nitrate promoted the reduction of Co2+ to metallic state in cobalt acetate by H2 spillover mechanism during catalyst reduction process.
Enhanced Luminescence of Lanthanide(III) Complexes in Polymer Matrices
Authors: Hasegawa Yasuchika , Sogabe Kensaku , Wada Yuji , Kitamura Takayuki , Nakashima Nobuaki , Yanagida Shozo
Published: May 2003

Effectively luminescent organic polymers were successfully fabricated by incorporating deuterated hexafluoroacetylacetonato Nd(III) or Eu(III) complex and DMSO-d6 in polyalkylmethacrylate matrices with low percentage of H atoms.
Isolation of Silk Degrading Microorganisms and Its Poly(l-lactide) Degradability
Authors: Tokiwa Yutaka , Konno Mariko , Nishida Haruo
Published: May 2003

To examine a hypothesis that microorganisms regard poly(l-lactide) (PLLA) as a protein substrate like silk, a silk-utilizing actinomycete, Amycolatopsis sp. strain KT-s-9, was isolated. The strain KT-s-9 was confirmed to degrade and utilize silk fibroin rapidly. By the clear zone method, it was determined that the strain KT-s-9 can also degrade PLLA.
Formation of Defects in Near-Surface Region over Li or Mn-Doped MgO Studied by Mg K-Edge XANES
Authors: Aritani Hirofumi , Yamada Hiroyuki , Nishio Takashi , Imamura Seiichiro , Hasegawa Sadao , Tanaka Tsunehiro , Yoshida Satohiro
Published: May 2003

The near-surface region of Li or Mn-doped Mg was characterized by Mg K-edge XANES spectroscopy. The oxygen defects were formed in near-surface region when the content of Li or Mn ion is relatively low. The amount of the defects in near-surface region does not depend on the crystallinity.
An Oxo- and Chloro-Bridged Dimeric Molybdenum(III) Ethylenediamine Complex
Authors: Kiyoda Shunji , Akashi Haruo , Ohtani Tsukio , Shibahara Takashi
Published: May 2003

An oxo- and chloro-bridged dimeric molybdenum(III) ethylenediamine complex, [Mo2(μ-O)(μ-Cl)(en)4](S2O2)Cl·3H2O (1) was synthesized from the mononuclear complex [MoCl3(thf)3], and was characterized structurally and spectroscopically for the first time. The Mo(1)-Mo(2) distance in 1 is 2.495(1) Å, and the formal bond order may be three (σ2π2δ2). The trans influence of μ-O on the Mo-N bond lengths proved to be greater than that of μ-Cl.
Fabrication of Polymer/Inorganic Nanoparticles Composite Films Based on Coordinative Bonds
Authors: Hao Encai , Wang Liyan , Zhang Junhu , Yang Bai , Zhang Xi , Shen Jiacong
Published: May 2003

We reported a new approach for fabrication of a multilayer film through coordinate bonds of pyridine polymers and CdS nanoparticles, which was identified by UV-Vis and FTIR spectroscopy.
Catalytic C-H Bond Activation-Asymmetric Olefin Coupling Reaction: The First Example of Asymmetric Fujiwara-Moritani Reaction Catalyzed by Chiral Palladium(II) Complexes
Authors: Mikami Koichi , Hatano Manabu , Terada Masahiro
Published: May 2003

The first example of the asymmetric Fujiwara-Moritani reaction catalyzed by chiral Pd(II) complexes is reported to represent a catalytic aromatic C-H bond activation-asymmetric olefin coupling reaction.
Pyrido[3,4-c]Thiazoles through Combined Palladium-Catalysed Coupling of 2-Substituted-5-acetyl-4-thiazolyltriflates with Alkynes/Annulation Reactions
Authors: Arcadi Antonio , Attanasi Orazio A , Guidi Barbara , Rossi Elisabetta , Santeusanio Stefania
Published: May 2003

2-Substituted-5-acetyl-4-thiazolyltriflates give in good yields functionalised pyrido[3,4-c]thiazoles through combined palladium-catalysed coupling with 1-alkynes/6-endo-dig annulation reactions in the presence of ammonia.
Substitution Effect on the Coloration Quantum Yield of a Photochromic Bisbenzothienylethene
Authors: Uchida Kingo , Tsuchida Eriko , Aoi Yoshifumi , Nakamura Shinichiro , Irie Masahiro
Published: May 2003

Introduction of isopropyl substituents to 2 and 2′ positions of benzothiophene rings of bis(1-benzothiophen-3-yl)hexa-fluorocyclopentene increased the population of anti-parallel conformation, and enhanced the quantum yield of the cyclization reaction.
Elongated H-H in trans-[Os(η2-H2)en2Cl]Cl
Authors: Hasegawa Tai , Li Zaiwei , Taube Henry
Published: May 2003

The structure of trans-[Os(η2-H2)en2Cl]Cl has been determined by X-ray analysis of a crystal at 118(2) K. A study of the two independent crystals confirms the trans arrangement. In both crystals the H-H bonds orientate along the N-Os axis and the H-H distances are in the mid-range between those of dihydride compounds and of dihydrogen.
Chiral Lewis Acid Catalysis in Aqueous Media. Catalytic Asymmetric Aldol Reactions of Silyl Enol Ethers with Aldehydes in a Protic Solvent Including Water
Authors: Kobayashi Shu , Nagayama Satoshi , Busujima Tsuyoshi
Published: May 2003

Chiral copper(II)-catalyzed asymmetric aldol reactions of silyl enol ethers with aldehydes have been successfully carried out in a water-ethanol solution. The use of the protic solvent including water is essential in these reactions, and this report has proposed and demonstrated a new concept for solvents in catalytic asymmetric aldol reactions.
A Novel Rearrangement of Chromium Allyloxy(aryl)carbene Complexes Catalyzed by Pd(0)
Authors: Sakurai Hidehiro , Tanabe Katsuhiko , Narasaka Koichi
Published: May 2003

Chromium allyloxy(aryl)carbene complexes undergo formal [2,3]- or [1,2]-sigmatropic rearrangement by the catalytic use of Pd(PPh3)4 under CO atmosphere. The reaction is considered to proceed via palladium aroyl π-allyl complex, which is converted to the corresponding aryl ketones by reductive elimination.
Photochemistry Determined by Light Propagation. Part 1 Three-dimensional Photomanipulation of Self-organized Azobenzenes in Liquid-Crystalline Polymers
Authors: Ichimura Kunihiro , Han Mina , Morino Shin-ya
Published: May 2003

Clear-cut observation of the reorientation and self-organization of azobenzene chromophores to the propagation direction of actinic light is described, using spin-cast thin films of a liquid crystalline azobenzene polymer.
A Light Induced Change in Cholesteric Pitch by Photoracemization of a Chiral Pyrenyl Sulfoxide
Authors: Tsurutani Yasuyuki , Machida Shinjiro , Horie Kazuyuki
Published: May 2003

A cholesteric phase of 4′-pentyl-4-biphenyl carbonitrile (5CB) doped with (R)-(+)-1-pyrenyl-4-tolyl sulfoxide (1) was observed. Changes in a cholesteric pitch, p, in the liquid crystalline phase was induced by photoracemization and agreed with a theoretical line. A helical twisting power, βM, of 1 in 5CB was obtained to be −1.1 μm−1 M−1. Anisotropy factor, g, of 1 in acetonitrile was determined to be 2.1 × 10−3 at 375 nm and 2.9 × 10−3 at 302 nm.
High Sensitive Oxygen Sensor Based on Quenching of Triplet-triplet Absorption of Fullerene C60-Polystyrene Film
Authors: Amao Yutaka , Asai Keisuke , Okura Ichiro
Published: May 2003

New optical oxygen sensor based on the quenching of triplet-triplet (T-T) absorption of fullerene (C60) molecules by oxygen using laser flash photolysis has been developed. The lifetime of T-T absorption of C60 in polystyrene decreases with an increase of oxygen concentrations. A Stern-Volmer plot of C60 exhibits considerable linearity (r2 = 0.999) and Ksv is estimated to be 0.50 %−1, indicating that C60 film is high sensitive oxygen sensor.
Direct Imaging of Concentration Profile over Interdigitated Dot Electrodes
Authors: Rashkov Rashko S , Aogaki Ryoichi , Nakabayashi Seiichiro
Published: May 2003

Time evolution of spherical diffusion layer over dot electrodes was observed by Mach-Zehnder laser interferometer. The current response of those interdigitated dot electrodes was varied by the geometry of the electrode. The interferograms explained this in terms of the variation of the convective ion flux under the gravitational field.
Electrophoretic Deposition of Copper Phthalocyanine from Trifluoroacetic Acid-Dichloromethane Mixed Solution
Authors: Yamanouchi Hiroaki , Irie Kazunobu , Saji Tetsuo
Published: May 2003

The formation of a copper phthalocyanine (1) thin film was carried out using a trifluoroacetic acid (2)/dichloromethane mixed solution containing protonated copper phthalocyanines. A blue film was formed on the cathodic plate with short time deposition by electrophoretic deposition using this solution. Scanning electron micrographs showed that this film is composed of fibrous crystallites.
Azobenzene-Appended Oligonucleotides Form Unexpectedly Stable Triple-Helixes
Authors: Asanuma Hiroyuki , Yoshida Takayuki , Liang Xingguo , Komiyama Makoto
Published: May 2003

Modified oligo(T)s carrying an azobebzene at the 5′-ends form unexpectedly stable triple-helixes with oligo(A)/oligo(T) double-helix. The triplex-stabilizing activity of the azobenzene is comparable with (or greater than) that of thymine.
Asymmetric Electrosynthesis of Amino Acid Using an Electrode Modified with Amino Acid Oxidase and Electron Mediator
Authors: Kawabata Susumu , Iwata Naoko , Yoneyama Hitoshi
Published: May 2003

Asymmetric synthesis of amino acid has been successfully achieved by electrochemical reduction of keto acid using an electrode on which amino acid oxidase and electron mediator are immobilized. The enantiomer excess closing to 100% was obtained.
A Safe Low Temperature Route to Nanocrystalline Transition Metal Arsenides
Authors: Xie Yi , Lu Jun , Yan Ping , Jiang Xuchuan , Qian Yitai
Published: May 2003

Nanocrystalline FeAs, CoAs and NiAs were prepared by keeping the mixture of FeCl3, CoCl2 or NiCl2 with arsenic and KBH4 in ethylenediamine (en) at 100 °C for 4 h, respectively. X-Ray powder diffraction (XRD) patterns and transmission electron microscope (TEM) images show that the products are orthorhombic FeAs, CoAs and hexagonal NiAs, respectively, and all are well crystalline in nanometers.
Synthesis of Bis(2-hydroxynaphthamide) Derivatives Behaving as a Fluorophore for Anions
Authors: Yoshida Hiroaki , Saigo Kazuhiko , Hiratani Kazuhisa
Published: May 2003

Bis(2-hydroxynaphthamide) derivatives have been synthesized via tandem Claisen rearrangement in high yields. These compounds are found to make complexes with anions and emit luminescence, serving as anion sensing fluorophores.
Enhanced Expression of Foreign Gene Transferred to Mammalian Cells in vitro Using Chemically Modified Poly(l-lysine)s as Gene Carriers
Authors: Yamaoka Tetsuji , Kimura Tsuyoshi , Iwase Reiko , Murakami Akira
Published: May 2003

Poly(l-lysine) (PL) is chemically modified on the basis of the commonly essential structures of effective gene carriers, which we previously found, in order to improve the insufficient gene-transferring efficacy of PL. The PL-derivatives were then subjected to gene transfer with the osmotic shock procedure. Poly(Nε-trimethyl-l-lysine-co-serine) (PtmLS) showed much higher transient gene expression than PL with low cytotoxicity while poly(Nε-trimethyl-l-lysine) and poly(l-lysine-co-serine) did not. These results strongly support the importance of both of the nonionic hydrophilic groups and quaternary ammonium groups of the gene carriers.
Enantioseparation by Using Chitin Phenylcarbamates as Chiral Stationary Phases for High-Performance Liquid Chromatography
Authors: Yamamoto Chiyo , Hayashi Tomoko , Okamoto Yoshio , Kobayashi Shiro
Published: May 2003

Three chitin derivatives, 3,6-bis(phenylcarbamate), 3,6-bis(3,5-dimethylphenylcarbamate), and 3,6-bis(3,5-dichlorophenylcarbamate), were prepared and their chiral recognition abilities as chiral stationary phases (CSPs) for high-performance liquid chromatography (HPLC) were evaluated. Among the three, the 3,5-dimethyl- and 3,5-dichlorophenylcarbamates showed a relatively high chiral recognition ability. Especially, some chiral acidic drugs such as ibuprofen and ketoprofen were efficiently resolved on the 3,5-dichlorophenylcarbamate.
An Efficient and Selective Oxidation of Benzylic Alcohols to the Corresponding Carbonyl Compounds under Solvent-Free Conditions
Authors: Hajipour Abdol Reza , Mallakpour Shadpour E , Mohammadpoor-Baltork Iraj , Khoee Sepideh
Published: May 2003

1-Benzyl-4-aza-1-azoniabicyclo[2.2.2]octanedichromate is a useful reagent for selective oxidation of benzylicalcohols and α-hydroxy ketones to the corresponding carbonyl compounds. The reaction was carried out under solvent-free conditions without or in the presence of a catalytic amount of aluminum chloride.
The Trityl Tetrakis(pentafluorophenyl)borate Catalyzed Stereoselective Glycosylation Using New Glycosyldonor, 3,4,6-Tri-O-benzyl-2-O-p-toluoyl-β-D-glucopyranosyl Phenylcarbonate
Authors: Takeuchi Kazuya , Tamura Takayuki , Mukaiyama Teruaki
Published: May 2003

The trityl tetrakis(pentafluorophenyl)borate [TrB(C6F5)4] catalyzed stereoselective synthesis of various disaccharides was successfully carried out by treating a new 2-O-acyl-protected glycosyl donor, 3,4,6-tri-O-benzyl-2-O-p-toluoyl-β-D-glucopyranosyl phenylcarbonate, with several glycosyl acceptors, thioglycosides, affording the corresponding disaccharides in high yields.
Synthesis of 1-Alkenylboronic Esters via Palladium-Catalyzed Cross-Coupling Reaction of Bis(pinacolato)diboron with 1-Alkenyl Halides and Triflates
Authors: Takahashi Kou , Takagi Jun , Ishiyama Tatsuo , Miyaura Norio
Published: May 2003

The synthesis of 1-alkenylboronic acid pinacol esters via the palladium-catalyzed cross-coupling reaction of 1-alkenyl halides or triflates with bis(pinacolato)diboron [(Me4C2O2)B-B(O2C2 Me4)] was carried out in toluene at 50 °C in the presence of potassium phenoxide (1.5 equivalents) and PdCl2(PPh3)2·2PPh3 (3 mol%).
Preparation of a Soluble Precursor by an Aminolysis Reaction of Zr(NEt2)4 and Its Pyrolytic Conversion into ZrN
Authors: Cheng Fei , Sugahara Yoshiyuki , Kuroda Kazuyuki
Published: May 2003

A novel soluble precursor with a Zr-N-Zr backbone structure was prepared by an aminolysis reaction of Zr(Net2)4 with PriNH2. Pyrolysis of the precursor under NH3-N2 atmospheres led to the formation of ZrN as a main crystalline phase with a ceramic yield of 45.2%. Aggregated particles consisting of very minute particles with diameters of 50-300 nm were obtained.
Reduction of Molybdenum(V) Chloride with Various Reducing Metals: Reactivity Correlations with the Descendant Lewis Acids
Authors: Hara Ryuichiro , Guo Qiaoxia , Takahashi Tamotsu
Published: May 2003

Reactivity of low-valent molybdenum prepared from MoCl5 with various reducing metals in DME, was dependent on the reducing metals in the order of Al > Sn, In > Zn, Mg, Li in the case of cyclotrimerization of alkynes. This order is parallel to the acidity of the descendant Lewis acids.
Catalytic Activity of Ir for NO-CO Reaction in the Presence of SO2 and Excess Oxygen
Authors: Ogura Masaru , Kawamura Aya , Matsukata Masahiko , Kikuchi Eiichi
Published: May 2003

Catalytic performance of Ir catalysts for reduction of nitric oxide with carbon monoxide in the presence of SO2 and excess oxygen was investigated. NO was selectively reduced with CO on Ir/silicalite in an oxidizing atmosphere containing 1% to 10% O2 in the temperature range of 300-500 °C. The catalytic activity was scarcely influenced by 150 ppm SO2.
Palladium Homobimetallic Complexes with Bridging π-Conjugated Ligands
Authors: Moriuchi Toshiyuki , Bandoh Seiji , Kamikawa Masayuki , Hirao Toshikazu
Published: May 2003

The palladium homobimetallic complexes 2a and 2b with a bridging π-conjugated molecule, N,N′-bis(4′-pyridylmethylidene)-1,4-phenylenediamine (L2a) and 2′-pyridyl derivative L2b, were respectively synthesized and characterized by X-ray crystal structure analysis and cyclic voltammetry. 1H-NMR of 2b indicates the five-coordinate geometry on the palladium center.
Tandem Aldol-Reduction Reaction of Dimethylsilyl Enolates: A New Method for Stereoselective Preparation of 1,3-Diols
Authors: Miura Katsukiyo , Nakagawa Takahiro , Suda Shuntaro , Hosomi Akira
Published: May 2003

In the presence of a catalytic amount of TBAF (Bu4NF), dimethylsilyl enolates derived from acyclic ketones reacted with aldehydes to give syn,syn-1,3-diols 7a and 8a with moderate to high diastereoselectivity. The stereochemical outcome can be attributed to a syn-selective aldol reaction and the subsequent 1,2-syn-selective intramolecular reduction.
Three-Dimensional Interpenetrating Network of [Ag2(hmt)(NO3)2]n
Authors: Bu Wei-Ming , Ye Ling , Fan Yu-Guo
Published: May 2003

The neutral network of [Ag2(hmt)(NO3)2]n was prepared and characterized by X-ray diffraction studies which reveal a novel interpenetrating three-dimensional framework based both on the metal ions bound to µ4-hmt ligands and anions bonding mode. The anion bridges give a unique helical cylinder structure motif.
The Effect of Hairpin DNA Fragments on Escherichia coli Poly(U)-Dependent Poly(Phe) Synthesis
Authors: Yoshizawa Satoko , Watanabe Kimitsuna , Miura Kin-ichiro , Hirao Ichiro
Published: May 2003

In the poly(U)-dependent poly(Phe) synthesis, we found that small hairpin DNA fragments overcome the decline in the translation efficiency caused by an excess amount of E. coli tRNAPhe. Of these fragments, hairpin DNAs with similar sequences to the unmodified D-arm or TΨC-arm of tRNAPhe were most effective.
Selective Hydrolysis of 4-Nitrophenyl Phosphate by a Dinuclear Cu(II) Complex
Authors: Kim Jung Hee
Published: May 2003

A flexible dinuclear Cu(II) complex with 1,3-bis(1,4,7-triaza-1-cyclononyl)propane, hydrolyzes 4-nitrophenyl phosphate under mild conditions, with 300 times rate enhancement over the corresponding mononuclear Cu(II) complex. In contrast, there is no difference in the reactivity in hydrolyzing bis(4-nitrophenyl)phosphate.
Effect of the Polymer Concentration on the Interactions of Water-Soluble Polymers with Metal Ions
Authors: Rivas Bernabé L , Moreno-Villoslada Ignacio
Published: May 2003

Despite poly(allylamine) forms a complex with Ni2+ with three amino groups in the coordination sphere of the metal ion, the corresponding formation constant is of order one considering the polymer concentration. This supports the idea of the existence of polymeric domains with local high and nearly constant ligand concentration. Analogous behavior is found for the system poly(sodium 4-styrenesulfonate) with Pb2+.
Palladium-Catalyzed Synthesis of α-Diketones from Acylchromates, Iodoarenes, and Carbon Monoxide
Authors: Sakurai Hidehiro , Tanabe Katsuhiko , Narasaka Koichi
Published: May 2003

A three-component coupling of tetramethylammonium pentacarbonyl(acyl)chromates, aryl iodides, and CO takes place under CO atmosphere in the presence of a catalytic amount of Pd(PPh3)4 to afford the corresponding unsymmetrical α-diketones in good yield. By performing the reaction under argon atmosphere, unsymmetrical ketones are prepared instead of α-diketones.
Molecular Formula Determination of Constituents in Arabian Mix Vacuum Residue by Electrospray Ionization Fourier Transform Ion Cyclotron Resonance Mass Spectrometry
Authors: Miyabayashi Keiko , Suzuki Keita , Teranishi Toshiharu , Naito Yasuhide , Tsujimoto Kazuo , Miyake Mikio
Published: May 2003

Fourier transform ion cyclotron resonance mass spectrometry equipped with electrospray ionization (ESI FT ICR MS) was successfully applied to determine molecular formulas of components in Arabian mix vacuum residue (AM-VR) by measurement of highly accurate m/z values of molecular ions and analysis of spectral pattern without any pre-separation procedures.
Promotional Effect of Noble Metal to Co-based Fischer-Tropsch Catalysts Prepared from Mixed Cobalt Salts
Authors: Sun Shouli , Tsubaki Noritatsu , Fujimoto Kaoru
Published: May 2003

Addition of very small amount of Ru, Pt and Pd exhibited great effect on the Co-based catalysts prepared by mixing impregnation of cobalt (II) nitrate and cobalt (II) acetate. Added small amount of Ru to this kind of catalyst showed extremely high activity, while no apparent CH4 selectivity change was observed. However, added Pt and Pd hardly exerted effect on the activity of Co-based catalyst, but increased CH4 selectivity remarkably.
Remarkably Slow Aggregation of a Styrylpyrazine Amphiphile in Aqueous Dispersion
Authors: Park Jong-mok , Zhang Wanbin , Nakatsuji Yohji , Majima Tetsuro , Ikeda Isao
Published: May 2003

Styrylpyrazine amphiphile 1 in aqueous dispersion showed a remarkably slow aggregation process. Evidence supporting the “translation” layered structure of 1 having face-to-face stacking in the aggregate was obtained by the blue-shifted fluorescence spectra by the aggregation in contrast with the red-shift for stilbene amphiphile 2.
Low Symmetrical Phthalocyanines Having Spectroscopic and Electrochemical Properties Characteristic of Unexpected Accidental S1 State Degeneracy and Non-Planar Distortions
Authors: Nemykin Victor N , Kobayashi Nagao , Nonomura Taro , Luk’yanets Eugene A
Published: May 2003

Low-symmetrical phthalocyanines (Pcs) 2-5 prepared by mixed condensation of tetraphenylphthalonitrile and 4-phenylthiophthalonitrile in the presence of a copper salt, show spectroscopic, electrochemical, and molecular model indications which suggest varying degrees of non-planar distortions of the Pc plane and unexpected S1 state degeneracy.
Substituent Effects on Catalytic Synthesis and Properties of Poly(phenylsilane)
Authors: Hashimoto Hisako , Obara Sachiko , Kira Mitsuo
Published: May 2003

Catalytic dehydrogenative polymerization of phenylsilanes with electron-withdrawing substituents using dimethylzirconocene as a catalyst afforded the corresponding polysilanes with rather high molecular weights. Significant substituent effects were observed on the electronic spectra of the polymers.
Complete End-Capping during the Copolymerization of Trioxane and Ethylene Oxide
Authors: Nagahara Hajime , Hamanaka Katsuhiko , Yoshida Kohichi , Kagawa Kenji , lwaisako Toshiyuki , Masamoto Junzo
Published: May 2003

Complete end-capping during the copolymerization of trioxane and ethylene oxide in the bulk polymerization state using boron trifluoride dibutyl ether as the initiator and methylal as the chain transfer agent was accomplished. By using highly purified trioxane as the starting material and by completely deactivating the catalyst residue, an almost completely end-capped polymer (degree of stability was over 99.5%) was obtained.
Synthesis and Inclusion Properties of a Upper-rim-connected Biscalix[4]arene
Authors: Araki Koji , Hayashida Hiromi
Published: May 2003

The conformationally-immobile biscalix[4]arene was synthesized by connecting the upper rims with two spacers. It showed high inclusion ability and selectivity for quaternary ammonium ions. A comparison with reference compounds established that the enhanced selectivity is due to the cooperative action of two bowl-shaped calix[4]arenes.
Molecular Assembly of Zinc Bachteriochlorophyll a by Synthetic Hydrophobic 1α-Helix Polypeptides
Authors: Kashiwada Ayumi , Watanabe Hiroyuki , Tanaka Toshiki , Nango Mamoru
Published: May 2003

Synthetic 1α-helix hydrophobic polypeptides organized zinc bachteriochlorophyll a (Zn-BChl a) complex in n-octyl-β-d-glucopyranoside (OG) micelle analogous to the light-harvesting (LH) polypeptide complex of photosynthetic bacteria.
Photochemistry of Uranyl(VI) Tributylphosphate in Supercritical CO2: An Evidence of Photochemical Reduction by Ethanol
Authors: Fazekas Zsolt , Yamamura Tomoo , Park Yoon-Yul , Harada Masayuki , Tomiyasu Hiroshi
Published: May 2003

The photochemistry of uranyl(VI)-tributylphosphate (TBP) complex in supercritical carbon dioxide (scCO2) was studied in the pressure range of 8-40 Mpa and from 289 to 336 K. Deactivation rate constants decreased with the increase of pressure. Temperature dependence analysis of the deactivation rate constants indicated that scCO2 contributes differently to deactivation processes from liquid phase CO2 based on activation barriers. An UV irradiation experiment proved photochemical reduction of uranyl(VI)-TBP complex by ethanol in scCO2.
Cl2 Gas Sensor Using Na+ Conducting Solid Electrolyte
Authors: Aono Hiromichi , Sadaoka Yoshihiko
Published: May 2003

A composite Na+ conductor of polycrystalline NASICON mixed with a glassy Na2O-Al2O3-4SiO2 (40wt%) was used in Cl2 gas sensor. The probe using the composite electrolyte and a RuO2+NaCl (1 : 1) measuring electrode gave rapid EMF changes even for sub-ppm level of Cl2 gas concentration (below 6 ppm).
(R)-[1-(1-Naphthyl)ethyl] Isothiocyanate and (S)-1-Phenylethyl Isothiocyanate. New Chirality Recognizing Reagents for the Determination of Enantiomeric Purity of Chiral Amines by NMR
Authors: Jeon Dong Ju , Kim Jung Soo , Lee Jung No , Kim Hyoung Rae , Ryu Eung K
Published: May 2003

(S)-1-Phenylethyl isothiocyanate and (R)-[1-(1-naphthyl)ethyl] isothiocyanate which are easily formed and stable in aqueous conditions are utilized as new chirality recognizing reagents for the determination of enantiomeric purity of chiral amines by NMR.
Homogeneous Ce(IV) Complexes for Efficient Hydrolysis of Plasmid DNA
Authors: Sumaoka Jun , Igawa Tomoyuki , Furuki Kenichiro , Komiyama Makoto
Published: May 2003

Homogeneous Ce(IV) solutions, prepared by using appropriate additives, promptly hydrolyzed a plasmid DNA. The inactivity of Ce(IV)-hydroxide gel for this reaction, which is in contrast with its remarkable catalysis for the hydrolysis of linear DNA, has been ascribed to the steric hindrance between the supercoiled DNA and the polymeric catalyst.
Color Change of Ternary Associate by Drying on Membrane Filter for Visual Protein Detection
Authors: Yoshimoto Keitaro , Kaneko Emiko , Yotsuyanagi Takao
Published: May 2003

A simple yet highly sensitive method has been developed for visual detection of protein in an aqueous solution. The proposed method consists of the ternary association between protein and Bromochlorophenol Blue (BCPB), the extraction on a membrane filter, and the significant color change of the dye in the associate by drying.
Evaluation of Lewis Acidity of “Naked” Lithium Ion through Diels-Alder Reaction Catalyzed by Lithium TFPB in Nonpolar Organic Solvents
Authors: Fujiki Kanji , Ikeda Shin-ya , Kobayashi Hiroshi , Mori Akira , Nagira Akihisa , Nie Jin , Sonoda Takaaki , Yagupolskii Yurii
Published: May 2003

The Diels-Alder reaction of cyclopentadiene with methyl vinyl ketone was remarkably promoted by anhydrous LiTFPB as a Lewis acid catalyst both in dichloromethane and in toluene. Experimental and computational investigations revealed the effects of solvent, hydrating water molecules, and counter anions on the Lewis acidity of the “naked” lithium ion.
Complexation of C60 Fullerene with Cholesteryl Group-Bearing Pullulan in Aqueous Medium
Authors: Lai Douglas T , Neumann Markus A , Matsumoto Mutsuo , Sunamoto Junzo
Published: May 2003

Water-soluble complex between C60 fullerene and cholesteryl group-bearing pullulan (CHP) was prepared. C60 fullerene was dissolved in pyridine (10% v/v) in advance and then mixed with an aqueous CHP suspension (0.1 mg ml−1). The particle size of the formed complexes varied from 60 nm to 150 nm by the concentration of aqueous pyridine in final solution. The complex could retain its integrity for a long period of time without destruction upon heating or freezing.
Silica-Alumina-Supported Molybdena Catalyst for Propene Metathesis
Authors: Aritani Hirofumi , Fukuda Osamu , Yamamoto Takashi , Tanaka Tsunehiro , Imamura Seiichiro
Published: May 2003

Without reductive pretreatment, 10 wt% MoO3/SiO2-Al2O3 (JRC-SAH-1) exhibits high catalytic activity for propene metathesis. The Mo ions on SiO2-Al2O3 may exist as dispersed polyanions, and they can be reduced easily in contact with propene even at room temperature. The reduced Mo ions formed in the initial step of the reaction are efficient for metathesis.
CO2 Gas Sensing with the Combination of Trivalent Al3+ Ion Conducting Al2(WO4)3 Single Crystal Solid and Oxide Ion Conducting Stabilized Zirconia
Authors: Imanaka Nobuhito , Kamikawa Masayuki , Hiraiwa Masamichi , Tamura Shinji , Adachi Gin-ya
Published: May 2003

A carbon dioxide gas sensor was fabricated by using a trivalent Al3+ ion conducting Al2(WO4)3 single crystal solid with an oxide ion conducting stabilized zirconia and Li2CO3 as an auxiliary electrode. The sensor response was rapid and reproducible enough for a practical application. In addition, the sensor output was stable and the present sensor would be one of superior promising tool with a compact and maintenance-free type CO2 gas sensing.
A Benzene-Thermal Synthetic Route to Nanocrystalline ZrN
Authors: Hu Junqing , Lu Qingyi , Tang Kaibin , Deng Bin , Jiang Rongrong , Qian Yitai , Zhou Guien , Liu Xianming
Published: May 2003

Nanocrystalline ZrN has been successfully prepared via benzene-thermal reaction of ZrCl4 and NaN3 at 350-380 °C. X-ray powder diffraction patterns indicated that the crystallinity of ZrN was considerably high and the cell constant was a = 4.567 Å. Transmission electron microscopy images showed the powders consist of uniform spherical particles with a narrow particle-size distribution (10-20 nm). The role benzene-solvent played in the formation of nanocrystalline ZrN was discussed.
Non-Contact Measurement of Adsorbed Cytochrome c with Optical Waveguide Spectrometry; The Effect of Distance between Waveguide and Protein on the Spectral Sensitivity
Authors: Ohno Hiroyuki , Fukuda Kyoko , Kurusu Fumiyo
Published: May 2003

Optical waveguide spectrometry with non-contact conditions was performed with the aim of widening the choice of substrate material. The visible absorption spectrum of cytochrome c (cyt.c) adsorbed on a quartz glass or gold surface was detected with the evanescent wave from a co-faced waveguide. A clear correlation was observed between absorbance of cyt.c and the gap between the waveguide surface and the protein.
Difference of Electronic Structures between NaInO2 and NaInS2
Authors: Matsushima Shigenori , Kohiki Shigemi
Published: May 2003

The electronic structures of NaInO2 and NaInS2 are calculated by using the discrete variational X α method on model clusters. For NaInO2, it is found that the In-O bonding is not perfectly ionic but partially covalent because of the hybridization between O 2s, 2p and In 5s, 5p orbitals in the electron-occupied band. However, the overlapping of Na 3s, 3p orbitals with O 2s, 2p orbitals is very weak. On the other hand, Na 3s, 3p orbitals of NalnS2 relatively hybridize with S 3s, 3p orbitals, not only In 5s and 5p orbitals. These results show that the nature of the chemical properties of NaInS2 is more covalent, compared with NaInO2.
Colliding Spiral Waves Propagating on the Electrode
Authors: Nakabayashi Seiichiro , Inokuma Kiyoshi , Nakao Aiko , Krastev Ivan
Published: May 2003

Spiral waves consisted of deposited Ag and Sb were propagating two-dimensionally on a copper electrode surface while the electrochemical co-deposition of the metals was proceeding. A time course of this electrochemically driven wave-propagation was phenomenologically similar to the one driven by a homogeneous non-linear reaction in Belousov-Zhabotinsky (BZ) reaction-diffusion medium. The Ag/Sb co-deposition also formed a layered structure in the depth, finally it made a 3-dimensional super-structure on the electrode.
Synthesis and Properties of Alkylperoxocobalt(III) Porphyrin and Porphycene
Authors: Hayashi Takashi , Okazaki Kenshi , Shimakoshi Hisashi , Tani Fumito , Naruta Yoshinori , Hisaeda Yoshio
Published: May 2003

Alkylcobalt(III) and alkylperoxocobalt(III) species of porphyrin and porphycene have been prepared and characterized by UV-vis and 1H NMR spectroscopic measurements. Thermal decomposition of the alkylperoxocobalt species proceeds via Co–O or O–O bond cleavage, which depends on the coordination of an axial ligand.
New Ionic Conducting Polymer Composite Films Based on Partially Phosphorylated Poly(vinyl alcohol) and Poly(acrylic acid)
Authors: Suzuki Masahiro , Takada Naomi , Koyama Toshiki , Kobayashi Satoshi , Kimura Mutsumi , Hanabusa Kenji , Shirai Hirofusa , Miyata Seizo
Published: May 2003

Ionic conductivity of a composite film consisting of partially phosphorylated poly(vinyl alcohol) (P-PVA) and poly(acrylic acid) (PAA) is increased about three orders of magnitude over that of P-PVA film.
Photochromism of 2-Hydroxy-4′-methoxychalcone: A Novel Photon-Mode Erasable Optical Memory System with Nondestructive Readout Ability
Authors: Horiuchi Hiroaki , Shirase Hitoshi , Okutsu Tetsuo , Matsushima Ryoka , Hiratsuka Hiroshi
Published: May 2003

The photochromic system of 2-hydroxy-4′-methoxychalcone was found to be a novel photon-mode erasable system with nondestructive readout ability. The fatigue resistant property of the photochromic system of 2-hydroxy-4′-methoxychalcone has been confirmed at least up to 10 write-and-erase cycles.
Simple and Sensitive Detection Cell for Capillary Electrophoresis-Chemiluminescence Analysis Using Peroxyoxalate Reagent
Authors: Tsukagoshi Kazuhiko , Otsuka Miwa , Hashimoto Masahiko , Nakajima Riichiro , Kimoto Hideshi
Published: May 2003

Simple and convenient batch-type detection cells were developed for the capillary electrophoresis with chemiluminescence detection using peroxyoxalate reagent. A fused-silica capillary was directly inserted into the cell, and a grounding electrode was also done into it. The cell could be easily combined with capillary electrophoresis without any complex construction and expensive implements. A mixture of Dnsyl-amino acids was satisfactorily separated. Dnsyl-Trp was detected with the detection limit of 1 × 10−8 M by use of a glass cuvette-type cell.
An Energy Model for Bifurcation Analysis of a Double-Notched Concrete Panel: Continuum Model
Authors: Chen G. , Baker G.
Published: May 2003

In this paper, the uni-axial tension of double-notched concrete specimens is analyzed by using a continuum plasticity model. As in a companion paper, the concept of minimization of the second-order energy is used as the criterion for judging a bifurcation. The energy computation is formulated in standard continuum plasticity. The analysis confirms that the unsymmetrical crack propagation (i.e. strains localizing on one side of the specimen) may occur either before or after the peak load. Influences on bifurcation of three factors, the notch depth to panel width, the local constitutive law, and the ratio of the panel width to panel length are investigated. A larger ratio of the notch depth to panel width, a steeper softening constitutive law, and a smaller ratio of the panel width to panel length, leads to an earlier bifurcation. These conclusions are consistent with those obtained from a simplified model.
Untersuchungen zum Einfluß von Polyethlenglykol und Methoxypolylethylenglykol auf die radikalische Lösungspolymerisation von Acrylnitril in Dimethylformamid
Authors: Fritzsche P. , Schneider A.
Published: May 2003

Der Einfluß von Polyethylenglykol 400 und 2000 und von Methoxypolyethylenglykol 510 und 750 auf die radikalische Acrylnitrilpolymerisation in Dimethylformamid wurde dilatomerisch untersucht. Die übertragungskonstanten der Polyethylenglykole wurden sowohl unter Annahme von Disproportionierungsabbruch als auch für Abbruch durch Rekombination bestimmt.
Structure of the product of polymerization of 2,3‐epoxypropyl methacrylate in the presence of porous glass
Authors: Schneider B. , Doskočilová D. , Štokr J. , Tlusťáková M. , Kálal J.
Published: May 2003

From 1H‐ and 13C‐NMR and Raman spectra it was found that by the presence of a large surface of glass, the epoxide group of 2,3‐epoxypropyl methacrylate (EPMA) is completely decomposed, yielding 2,3‐dihydroxypropyl methacrylate and a number of additional low‐molecular‐weight products with double bonds. Polymerization of EPMA in the presence of porous glass yields poly(2,3‐epoxypropyl methacrylate). Part of this polymer is firmly bound to the glass, probably by means of the decomposition product of EPMA.
Zum Einfluß von Umesterungs‐ und Polykondensationskatalysatoren auf das Kristallisationsverhalten von Polyethylenterephthalat
Authors: Weigel P. , Zimmermann H.
Published: May 2003

Die Kinetik der isothermen Kristallisation von Polyethylenterephthalat aus dem Glaszustand wurde mittels Differentialkalorimetrie untersucht. Dabei konnte der Einfluß von Metallderivaten, wie sie zur Beschleungung der Umesterungs‐und Polykondensationsreaktion eingesetzt werden, auf das Kristallisationsverhalten nachgewiesen werden.
Ein geometrisches Modell für die Struktur hochorientierter, partiell‐kristalliner Polymere und dazugehöriges Modell für das Deformationsverhalten
Authors: Nitzsche K. , Vettegren V. I.
Published: May 2003

Bestimmend für das äußere Deformationsverhalten hochorientierter, fibrillarer Polymere ist das Deformationsverhalten eines fiktiven Strukturelements, das der Langperiode entspricht. Auf der Basis des geometrischen Modells für dieses Strukturelement und Kennwerten für das Deformationsverhalten der Makromoleküle verschiedener Konformation kann ein Modell für das Deformationsverhalten des polymeren Materials aufgestellt werden.
Zur dynamischen Modellierung des Reckprozesses von Polymerfäden. Teil 1: Entwicklung des mathematischen Modells
Authors: Beyreuther R. , Barthel R. , Nicht W.
Published: May 2003

Abgeleitet von praxisorientierten Fragestellungen zum Reckprozeß von Polymerfäden wird die Modellentwicklung zur mathematischen Nachbildung des kontinuierlichen, dynamischen Reckprozesses beschrieben. Ausgehend von der allgemeinen Differentialgleichung eines Kelvin‐Elements wird ein auf den Reckprozeß zugeschnittenes verallgemeinertes Kelvin‐Modell entwickelt. Der daraus abgeleitete Rechenalgorithmus gestattet es, den kontinuierlichen Prozeß sowohl örtlich als auch zeitlich in eine beliebige Anzahl von Einzelementen bzw. ‐schritten aufzulösen und nachzubilden.
Infrarotspektroskopische Untersuchungen an gepolten Polyvinylidenfluorid‐Folien
Authors: Danz R.
Published: May 2003

Die feldinduzierte Konformationsumwandlung und Dipol‐Orientierung in Polyvinylidenfluorid werden infrarotspektroskopisch quantitativ untersucht. Die Polung an beidseitig metallisierten, biaxial gereckten Polyvinylidenfluorid‐Folien bei 115°C mit 4,0 MV/cm führt zu einer nahezu vollständigen Konformationsumwandlung von der T‐G‐T‐G′‐ in die trans‐Konformation und zu einer remanenten Polarisation von mindestens 11 μC/cm2. Während die thermisch stimulierte Dipol‐Desorientierung oberhalb 60°C einsetzt, ist die feldinduzierte β‐Modifikation bis 175°C stabil.
Polymerization of some potential „grafting‐monomers”︁ for natural and synthetic fibres in cold plasma conditions
Authors: Simionescu C. I. , Dénes F. , Macoveanu M. M. , Totolin M. , Cazacu G.
Published: May 2003

Plasma induced solid‐state polymerization of some potential „grafting‐monomers”︁ (acrylamide, benzidine and alphanaphthylamine) for natural and synthetic fibres has been studied. Polymerization mechanisms have been suggested on the basis of the analytical data (IR, NMR, ESR spectroscopy, elemental analysis, gel‐filtration, swelling properties, DTA measurements) of the polymers obtained in cold plasma conditions.
Elektronenmikroskopische und mikroanalytische Untersuchungen zur Veränderung der übermolekularen Struktur von mit Natriumhydroxid‐Lösungen und Schwefelsäure behandelter Cellulose
Authors: Purz H. J. , Vetter J.
Published: May 2003

Durch elektronenmikroskopische Untersuchungen werden die Veränderung der übermolekularen Struktur der Cellulose bei der Einwirkung von NaOH und Schwefelsäure unterschieflicher Konzentration verfolgt und die Bedingungen ihrer Zerstörung ermittelt. Die Zerstörung der mikrofibrillaren Struktur durch NaOH‐Lösungen bzw. Schwefelsäure liegt bei den einzelnen Cellulosetypen in verschiedenen Konzentrationsbereichen. Die durch die Behandlung mit den Reagenzien gebildeten kristallinen Gebilde werden mittels Röntgenmikroanalyse auf ihre Elementzusammensetzung und mittels Elektronenbeugung auf ihre kristalline Struktur untersucht.
Reaktionsabhängige Teilchenvereinigung bei der Emulsionspolymerisation von Vinylchlorid
Authors: Goebel K.‐H. , Schneider H.‐J. , Jaeger W. , Reinisch G.
Published: May 2003

Bei der Emulsionspolymerisation von Vinylchlorid (Anfangsemulgatorkonzentration oberhalb der KMK) erfolgt insbesondere zu Beginn der Reaktion eine erhebliche Abnahme der Zahl der Latexteilchen. Die durch Latextitration und Ultrazentrifugation nachgewiesene Teilchenvereinigung ist nicht auf unzureichende Elektrolytstabilität der Partikel zurückführbar. Die Teilchenkonzentrationen bleiben konstant, wenn die Polymerisation durch Inhabitorzusatz oder Monomerverbrauch unterbrochen wird. Diese Befunde und Modellrechungen zur Kolloidstabilität auf Basis der DLVO‐Theorie weisen aus, daß Polymerisationsreaktion und Teilchenvereinigung in einem mechanistischen und kinetischen Zusammenhang stehen. Als mögliche Ursachen der Teilchenvereinigung werden erhöhte Emulgatordesorption von den polymerisierenden Teilchen sowie Brückenbildung zwischen Partikeln diskutiert.
Zur Struktur von p‐n‐Alkoxybenzoesäureestern im kristallin‐flüssigen Zustand
Authors: Tsukruk V. V. , Šilov V. V. , Lipatov Ju. S. , Konstantinov I. I. , Amerik Ju. B.
Published: May 2003

An einer Polymerreihe mit seitlichen Phenylbenzoatgruppen verschiedener Länge wurden eingehende röntgenographische Untersuchungen in einem weiten Temperaturbereich durchgeführt. Es konnte gezeigt werden, daß sehr lange flexible endständige Ketten ineinander eindringen. Eine Temperaturerhöhung führt zur Verbesserung der kristallin‐flüssigen Struktur bei Polymeren mit Methacrylat‐Hauptkette und zu einer gewissen Verschlechterung bei Polymeren mit Acrylat‐Hauptkette bei T > Tg.
Optimization of some compounds of polyvinylchloride with 2‐ethyl‐hexyl‐phthalate and an acrylic polymer
Authors: Adamescu Gh. , Petrovan S. , Rusu M. , Asandei N.
Published: May 2003

The influence of composition and processing parameters of polyvinylchloride‐acrylic polymer blends on the electrotechnical properties has been studied. Mathematical models were obtained, which can be used to predict the properties of the blends.