bluuebunny/crossref_metadata_2025_split huggingface dataset:
Structures of Dinuclear Copper(II) Complexes Bridged by One Oximato, One Methoxo and One Perchlorato Ligand, and One Oximato and Two Acetato Ligands
Authors: Sakamoto Sachiyo , Yatani Akihiro , Kimura Katsusi , Fujii Mie , Nakao Yasuo , Kashino Setsuo , Kinoshita Masashi , Mori Wasuke 
Published: December 2002

Abstract
The cation of [Cu(L1)(OMe)(ClO4)Cu(bpy)] ClO4 (1) consists of two coppers triply bridged by an oximato, a methoxo, and a perchlorato ligand, where L1 is 3-[2-(2-pyridyl)ethyl]amino-2-butanone oxime. The geometry around each copper is distorted square-pyramidal. The cation of [Cu(L1)(OAc)2Cu(bpy)]ClO4 (2), consists of two coppers triply bridged by an oximato, an unidentate and a bidentate acetato ligand. The geometry around the coppers is intermediate between a square pyramid and a trigonal bipyramid.
π-Interactions of Modified Nucleobases. On Mesomeric Purine Betaines with Inversed Charge Properties.
Authors: Schmidt Andreas , Kindermann Markus Karl 
Published: December 2002

Abstract
Intermolecular interactions of modified nucleobases with altered charge properties in relation to natural systems are studied. We prepared conjugated mesomeric betaines of purines and examined their properties by semiempirical calculations, 1H NMR titrations and ESI mass spectrometry. Thus, nucleophilic substitutions of 4-(dimethylamino)pyridine and pyridine, respectively, on 2-amino-6-chloropurine 1 and 2,6-dichloropurine 2 resulted in the formation of purin-6-yl hetarenium salts 3–6. These were converted into the conjugated mesomeric betaines 7–10, respectively, on treatment with the anion exchange resin Amberlite® IRA-400 in its hydroxy form. The betaines 7–10 possess umpoled purine rings in relation to 7-methylguanine that forms the betainic 5′-cap structure of m-RNA. We studied the π-stacking interactions of the conjugated mesomeric betaine 8 and of its cationic precursor 4 with l-tryptophan, adenine, adenosine, and guanosine in deuterated water.
The Reaction of Peroxynitrite with Organic Molecules Bearing a Biologically Important Functionality. The Multiplicity of Reaction Modes as Exemplified by Hydroxylation, Nitration, Nitrosation, Dealkylation, Oxygenation, and Oxidative Dimerization and Cleavage
Authors: Nonoyama Nobuaki , Oshima Hiroshi , Shoda Chizuru , Suzuki Hitomi 
Published: December 2002

Abstract
The reactions of peroxynitrite with a variety of organic molecules which include a biologically important functionality have been examined to construct a simple model for the peroxynitrite-induced in vivo transformations as well as a chemical probe for the active species involved therein. Phenols were found to undergo hydroxylation, nitration, oxidative dimerization, and oxidation to cyclohexadienones and quinones. The ring nitration of catechol was confirmed for the first time in the in vitro reaction of peroxynitrite. Dealkylation and N-oxide formation were the major reaction modes observed for N,N-dimethyl-p-toluidine. 1,2-Phenylenediamine gave benzotriazole in high yield. The electron-deficient C–C double bond in 1,4-naphthoquinone underwent epoxidation, while the electron-rich C–C double bond in α-methylstyrene suffered oxidative cleavage to acetophenone. The activated double bond in trans-stilbene underwent oxidative cleavage and epoxidation in parallel to give benzaldehyde and trans-stilbene oxide as the major products. The triple bond in diphenylacetylene was simply oxygenated to form benzil, together with trace amounts of ring nitration products. 1-Phenylethanol, imidazole, 2′-deoxyadenosine, and 2′-deoxyguanosine were all quite slow to react, while uracil and cytosine were almost inert to peroxynitrite. The reaction modes exhibited by peroxynitrite are too widespread and complicated to explain the whole mechanistic pathway in terms of a single active species. All reaction modes observed for the peroxynitrite to date could be classified into five categories according to their types: i) electron transfer type, ii) O-electrophilic type, iii) N-electrophilic type, iv) O-nucleophilic type, and v) radical type. Some of these may compete under certain conditions. The active species involved in each of these types of reactions are as follows: i) NO+, NO2, and OH, ii) ONOOH, iii) ONOOH and NO+, iv) OOH− and ONOO−, and v) NO2 and OH•.
Palladium-Catalyzed Synthesis of Biaryls from Arylzinc Compounds Using N-Chlorosuccinimide or Oxygen as an Oxidant
Authors: Hossain Kabir M , Kameyama Toru , Shibata Takanori , Takagi Kentaro 
Published: December 2002

Abstract
In the presence of a catalytic amount of Pd2+ or Pd0, oxidative homo-coupling of arylzinc compounds was achieved by the use of N-chlorosuccinimide (NCS) or O2 as an oxidant. Different reaction pathways were involved in the catalytic reactions depending on the oxidants; NCS or O2 probably oxidized I− or Pd0 to I+ or Pd2+, respectively. This reaction disclosed a new and facile synthetic method of biaryls from aryl halides or arenes via arylzinc intermediates.
EPR Studies at High-Pressure. VI. Spin-Exchange Reaction of Nitroxide Radical with Copper(II) and Iron(III) Complexes
Authors: Sueishi Yoshimi , Hori Arimitsu 
Published: December 2002

Abstract
The spin exchange of nitroxide with copper(II) and iron(III) complexes was studied by means of a high-pressure EPR technique. The spin exchange with CuII complexes exhibited the aspect of weak exchange, independent of the kinds of coordinated ligands, while the spin exchange with FeIII complexes was found to vary from weak exchange to a strong one, dependent of the solvent viscosity. Based on the results, the spin exchange with CuII and FeIII complexes is discussed in detail.
Synthesis and Crystal Structure of a Calix[4]arene-Based Dual Boron–Dipyrrin System.
Authors: Nishioka Takuya , Arimura Takashi , Suga Yasuhiro , Murata Shigeo , Tachiya M , Goto Midori 
Published: December 2002

Abstract
The preparation of a calix[4]arene-based dual boron–dipyrrin system was accomplished by the condensation of diformylcalix[4]arene and pyrrole followed by a treatment with DDQ and diethyl ether–boron trifluoride (1/1). An X-ray crystal structure analysis and spectroscopic measurements revealed that the cone conformation of calix[4]arene serves to define 14.9 Å as the center-to-center boron–dipyrrin separation.
Liquid-Crystalline Properties of Dissymmetric Molecules Part 8: The Effect of Conformation on the Mesomorphic Properties for Liquid–Crystal Compounds Having a Lateral Long Alkoxy Group
Authors: Wu Jianwei , Okamoto Hiroaki , Morita Yuki , Takenaka Shunsuke 
Published: December 2002

Abstract
This paper describes the liquid–crystal properties of 4-(4-alkoxyphenoxycarbonyl)phenyl 3-alkoxy- (1), 3-alkoxy-4-methyl- (2), and 3-alkoxy-2-methyl-benzoates (3). Most of the homologs of 1 are non-mesogenic, due to the long alkoxy group at the 3 position restraining the appearance of liquid–crystal properties. The substitution of a methyl group at the 2 or 4 position effectively facilitates the appearance of a nematic phase. The average effective order for the nematic-isotropic transition temperatures is 3 &gt; 2 &gt; 1. The liquid–crystal properties of these compounds are discussed in terms of the change in the conformation of the alkoxy group at the 3 position.
Optical Oxygen Sensing Material: Terbium(III) Complex Adsorbed Thin Film
Authors: Amao Yutaka , Ishikawa Yuichi , Okura Ichiro , Miyashita Tokuji 
Published: December 2002

Abstract
A new optical oxygen sensor based on the luminescence intensity change of a terbium(III) complex, tris(acethylacetonato)(1,10-phenanthroline)terbium(III) complex, ([Tb(acac)3(phen)]), adsorbed thin film onto an alumina plate, was developed. The luminescence peak positions of [Tb(acac)3(phen)] film were observed at 490, 546, 590 and 620 nm. The luminescence intensities of [Tb(acac)3(phen)] in the film decreased with increasing the oxygen concentration, indicating that the film can be used as an optical oxygen sensing device based on luminescence quenching by oxygen. The ratio I0/I100 (I0 and I100 represent the detected luminescence intensities from the film exposed to 100% argon and 100% oxygen, respectively) values of [Tb(acac)3(phen)] film are estimated to be 2.66 (490 nm), 2.68 (546 nm), 2.67 (590 nm) and 2.66 (620 nm), respectively. [Tb(acac)3(phen)] film obeyed a Stern–Volmer plot with a multi-site model and possessed good operational stability. The response times of the [Tb(acac)3(phen)] film were 7.3 s for switching from argon to oxygen, and 70 s for switching from oxygen to argon.
Solvent-dependent Anion Studies on Enrichment of Metallofullerene
Authors: Sun Baoyun , Gu Zhennan 
Published: December 2002

Abstract
Gd@C82 and Gd2@C80 were selectively reduced and extracted directly from the raw soot. Meanwhile, other metallofullerenes including insoluble M@C60, M@C70 (M = Gd,Y) were extracted and effectively enriched as anions. These studies present a new route to isolate metallofullerenes in the form of anions.
Synthesis and Binding Studies of Bowl-Shaped Hosts for Quaternary Ammoniums
Authors: Jeong Kyu-Sung , Shin Kwang Hoon , Kim Soong-Hyun 
Published: December 2002

Abstract
Two bowl-shaped hosts for quaternary ammonium salts were synthesized and their binding properties, along with the anion effect, were systematically examined and compared in CDCl3.
Metal Coating of DNA Molecules by Cationic, Metastable Gold Nanoparticles
Authors: Yonezawa Tetsu , Onoue Shin-ya , Kimizuka Nobuo 
Published: December 2002

Abstract
Metastable cationic gold nanoparticles were newly developed by the use of thiocholine bromide (TCB) as stabilizer. The gold nanoparticles electrostatically bound to DNA molecules and then underwent self-fusion into the wire-like structures. The use of TCB as a labile ligand was essential to achieve non-electrochemical plating of the non-conductive molecules.
Mechanochemical Synthesis of Nano-sized Complex Fluorides from Pair of Different Constituent Fluoride Compounds
Authors: Lu Jinfeng , Zhang Qiwu , Saito Fumio 
Published: December 2002

Abstract
Complex fluorides ARF4 (A = Li, Na, K, R = rare earthes) are synthesized by the mechanochemical solid reactions of AF and RF3 powders at room temperature using a planetary ball mill. The reactions proceed with the increase of grinding time and have been completed at 4 h. Transmission electron microscope observation shows that the produced ARF4 powders consist of agglomerates of nano-sized primary particles, which exhibit moderate water solubility. When the ground sample is calcined, the particle size is increased and the water solubility is depressed.
Computational Study of Transmission Function in p-Phenylene Sulfide and Benzothiophene Oligomers
Authors: Tantirungrotechai Yuthana , Wijitkosoom Atchara , Tonmunphean Somsak 
Published: December 2002

Abstract
The transmission function T(E), which describes the conduction in molecule, and the density of state (DOS) of the helical p-phenylene sulfide oligomer and of the fused-planar benzothiophene oligomer were calculated by using the nonequilibrium Green’s function formalism. Although both the oligomers consist of benzene-(1,4)-dithiolate subunit, they have different T(E) and DOS near the Fermi level. The effect of replacing a sulfur atom inside the oligomer by an oxygen atom was additionally investigated.
Preparation of Functional Core-shell Particles by Heterocoagulation
Authors: Yamaguchi Keizo , Ito Masaki , Taniguchi Tatsuo , Kawaguchi Seigou , Nagai Katsutoshi 
Published: December 2002

Abstract
Cationic polymer shell particles with sulfonium groups were immobilized at hydrophobic surfaces of cross-linked polystyrene particles as core particles by heterocoagulation. Composite polymer particles with a core-shell structure were produced by heat treatment at a temperature above the Tg of shell particles.
Direct Determination of Chlortetracycline by a Fluorescent Microscopic Ring-like Deposit Technique
Authors: Li Yuan Fang , Huang Cheng Zhi 
Published: December 2002

Abstract
Because of solvent evaporation, a droplet of chlortetracycline (CTC) solution containing 0.01 mol/L hexahydropyridine and 0.06%PVA-124, when spotted on a pretreated hydrophobic surface of glass slide, can form a ring-like deposit (RLD) with the outer diameter of 1.13 mm and ring belt width of 41 μm. The formed RLD can be used for CTC determination from pmol to fmol with the limit of detection of 4.7×10−15 mol (3σ).
Alkyl Self-assembled Monolayer Prepared on Hydrogen-terminated Si(111) through Reduced Pressure Chemical Vapor Deposition : Chemical Resistivities in HF and NH4F Solutions
Authors: Saito Nagahiro , Youda Satoko , Hayashi Kazuyuki , Sugimura Hiroyuki , Takai Osamu 
Published: December 2002

Abstract
Hexadecyl self-assembled monolayers have been prepared on hydrogen-terminated Si(111) substrates through reduced pressure chemical vapor deposition. Chemical resistvities to HF and NH4F of SAMs were studied.
Crystal Structure and Gas Adsorption Property of Rhodium(II) Benzoate Pyrazine
Authors: Takamizawa Satoshi , Hiroki Taku , Nakata Ei-ichi , Mochizuki Katsura , Mori Wasuke 
Published: December 2002

Abstract
The structure of a linear chain complex [Rh(II)2(O2CPh)4(pyz)]∞ was characterized by X-ray diffraction analysis. The solid indicates nitrogen adsorption on a microporous medium although the crystal does not seem to have a microporous structure. There is a high possibility that the structure changes to open the crystal packing for gas molecules.
Axial Extension of Metal String Complexes: Crystal Structure of {Ni3(dpa)4[Ag(CN)2]2}
Authors: Zhu Long-Guan , Peng Shie-Ming , Lee Gene-Hsiang 
Published: December 2002

Abstract
A novel complex, Ni3(dpa)4[Ag(CN)2]2 (1), was synthesized and structurally characterized. The first example of metal string complex with axial metallic ligand shows length of 20.5 Å. Axial [Ag(CN)2]− ligands still remain two vacant sites, which potential possibly form longer string complex.
Montmorillonite K10 Clay Catalyzed Mild, Clean, Solvent Free One-pot Protection-Isomerisation of the Baylis–Hillman Adducts with Alcohols
Authors: Shanmugam Ponnusamy , Rajasingh Paramasivan 
Published: December 2002

Abstract
The montmorillonite K10 clay catalyzed mild, clean, and solvent free one-pot reactions of the Baylis–Hillman adducts with a number of alcohols undergo secondary alcohol protection followed by a facile 1,3-sigmatropic shift isomerised products in excellent yield. The isomerised products with propargyl alcohol are highly functionalized and useful for lignan natural product synthesis.
A High-active Oxygen Electroreduction Catalyst Insensitive to the Presence of Methanol
Authors: Sawai Keijiro , Suzuki Nobuhisa 
Published: December 2002

Abstract
A high-active oxygen reduction catalyst was prepared by heat-treatment of transition metal hexacyanometalate precursors containing cobalt and iron dispersed on carbon black under an inert atmosphere. The catalytic activity for oxygen reduction was insensitive to the presence of high concentration of methanol and was comparable to that of the platinum catalyst in the absence of methanol.
Fabrication of Ideally Ordered Nanohole Arrays in Anodic Porous Alumina Based on Nanoindentation Using Scanning Probe Microscope
Authors: Masuda Hideki , Kanezawa Kenji , Nishio Kazuyuki 
Published: December 2002

Abstract
Ideally ordered hole array structures in anodic porous alumina were prepared by pretexturing Al using a nanoindentation apparatus equipped with a scanning probe microscope. The shallow concaves formed by the nanoindentation initiated hole development, and guided the growth of holes during the anodization. Hole arrays with hole intervals from 100 to 400 nm were fabricated by changing the intervals of concaves by nanoindentation with the scanning probe microscope.
Unique Grinding Effect of Orthorhombic LiMnO2 Material
Authors: Lee Yun-Sung 
Published: December 2002

Abstract
Well-defined orthorhombic LiMnO2 was synthesized using LiOH and γ-MnOOH as starting materials at 1000 °C in an argon atmosphere by quenching method. It showed a very small initial discharge capacity of about 34 mAh/g at room temperature. However, after a 24 h grinding, the LiMnO2 delivered not only a large initial discharge capacity of 210 mAh/g, but also a high cycling retention rate of 96% in the (3+4) V region after 50 cycles. We found that the grinding treatment was very effective to activate lithium insertion/extraction into the LiMnO2 layers in the 3 V region.
2-Vinylpyridine as Film-forming Additve to Suppress the Degradation of Carbon Anode by Dissolved Manganese for C/LiMn2O4 Rechargable Battery
Authors: Komaba Shinichi , Ohtsuka Tatsuya , Kaplan Benjamin , Itabashi Tatsuya , Kumagai Naoaki , Groult Henri 
Published: December 2002

Abstract
For lithium-ion batteries of C/(spinel Li–Mn–O), the sever capacity loss occurs after storage of the battery at &gt;50 °C. This is mainly due to degradation of the carbon which was induced by electroreduction of Mn(II) dissolved from the spinel; this step is followed by the irreversible electrochemical reaction at the graphite/(Mn deposits)/electrolyte interface. However, 2-vinylpyridine as an additive into the electrolyte was capable of suppressing this degradation of graphite anode, therefore, improved the battery performances. During the first charge, electropolymerization of 2-vinylpyridine from about 0.9 V vs Li/Li+ resulted in film formation of poly(2-vinylpyridine) on the anode surface. The polymer protected the graphite from dissolved Mn(II).
Direct Sol-Gel Replication of the Self-assembled Nanostructure Modified with H-bond Functionalities
Authors: Jung Jong Hwa , Shimizu Toshimi 
Published: December 2002

Abstract
The glucopyranoside-based amphiphile 1 formed nanofiber structures with 25–100 nm of diameters and several micrometer lengths in the presence of aminophenyl glucopyranoside 2, and their self-assembled nanostructures were successfully replicated into the silica tube by sol-gel polymerization of TEOS.
Solvatochromic Nanowires Self-assembled from Cationic, Chloro-bridged Linear Platinum Complexes and Anionic Amphiphiles
Authors: Lee Chang-Soo , Kimizuka Nobuo 
Published: December 2002

Abstract
A newly developed lipid-packaged one-dimensional complex of platinum shows solvatochromism in organic media. The use of anionic lipids as counter anions is indispensable for the solvent-dependent control of one-dimensional electronic states, aggregate morphology and thermal stability.
Design, Fabrication, and Application of Thermostructural Composites (TSC) like C/C, C/SiC, and SiC/SiC Composites
Authors: Christin F. 
Published: December 2002

AbstractThe French company Snecma Moteurs is a leading producer of high‐performance composites for operation under high mechanical stress and at high temperature, such as in jet engines, aircraft brake disks, or even rocket propulsion systems. The author presents the different families and generations of carbon‐carbon and ceramic‐matrix composites developed by Snecma, and discusses their manufacture and characteristics.
Actin‐bindende marine Makrolide: Totalsynthese und biologische Bedeutung
Authors: Yeung Kap‐Sun , Paterson Ian 
Published: December 2002

AbstractMarine Organismen produzieren eine faszinierende Vielfalt von Sekundärmetaboliten unterschiedlicher Struktur mit häufig ungewöhnlichen und manchmal unerwarteten biologischen Wirkungen. Ihre strukturelle Diversität macht diese marinen Naturstoffe zu ausgezeichneten Testverbindungen für die Untersuchung biochemischer Mechanismen. Kürzlich wurden aus verschiedenen marinen Organismen mehrere neue, stereochemisch komplexe Makrolide mit großem Lactonring (22‐ bis 44‐gliedrig) isoliert, die mit dem Actin‐Cytoskelett wechselwirken. Actin ist wie Tubulin ein Hauptbestandteil des Cytoskeletts und hat wichtige zelluläre Funktionen. Auch wenn die Einzelheiten dieser Wechselwirkungen noch untersucht werden, erhalten diese marinen Makrolide zunehmend Bedeutung als neue Testverbindungen zur Aufklärung der zellulären Wirkungen von Actin. Wegen ihrer starken Antitumorwirkung kommen diese Verbindungen, z. B. die Aplyronine, für Anwendungen in der vorklinischen Entwicklung der Krebs‐Chemotherapie infrage. Ihre interessanten Molekülstrukturen mit einer Fülle von Stereozentren und ihre biologische Bedeutung haben angesichts ihres äußerst begrenzten Vorkommens in marinen Organismen ein enormes Interesse an der Synthese dieser Verbindungen geweckt. Dieser Aufsatz gibt einen Überblick über die biologischen Eigenschaften dieser ungewöhnlichen Naturstoffe und schildert die kürzlich beendeten Totalsynthesen von Swinholid A, Scytophycin C, Aplyronin A, Mycalolid A – alle sind stark cytotoxische Actin‐bindende Wirkstoffe – und eines Diastereomers von Ulapualid A. Dabei wird nicht jeder Einzelschritt dieser vielstufigen Totalsynthesen detailliert beschrieben, vielmehr werden unterschiedliche Synthesestrategien, Schlüsselreaktionen und Methoden zur Steuerung der Stereochemie verglichen.
Polyhydroxyethylmethacrylate/polyhydroxybutyrate composite membranes for fluoride release
Authors: Yıldırmaz Gülbahar , Akgöl Sinan , Arıca M. Yakup , Sönmez Hayriye , Denizli Adil 
Published: December 2002

AbstractControlled release technology is a recent technology which has considerable potential in the fields of medicine, pharmacy, and agriculture. Fluoride ion is commonly used in the preventive treatment of decay, and when provided with extra fluoride, children living in regions that lack fluoride benefit from it. For the present study, clinical properties of an intraoral controlled release fluoride delivery system were considered. The preparation of a controlled release membrane system is described. Polyhydroxyethylmethacrylate/polyhydroxybutyrate composite systems were examined as fluoride carriers. Polymeric membranes were prepared by photopolymerization and then characterized. Contact angles and swelling ratios of fluoride‐loaded membranes were determined. The surface morphology of the microporous membranes were examined by using scanning electron microscopy (SEM). In vitro fluoride release studies were carried out in an artificial saliva medium. The amount of released fluoride was determined and the effect of medium pH and temperature on fluoride release was investigated. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 976–981, 2003
Reinforcement of natural rubber latex film by ultrafine calcium carbonate
Authors: Cai Han‐Hai , Li Si‐Dong , Tian Guo‐Ren , Wang Hua‐Bi , Wang Jian‐Hong 
Published: December 2002

AbstractUsing ultrafine calcium carbonate to reinforce natural rubber latex film, the effect of its content on latex properties such as surface tension, viscosity, mechanical stability, and heat stability and the physical properties of latex film before and after aging such as tear strength, modulus, and tensile strength were investigated. The results showed that the surface tension of natural rubber latex reinforced by ultrafine calcium carbonate only changed slightly; when the content of calcium carbonate was less than 20%, the change of viscosity was not obvious, but when the content was greater than 20%, the viscosity significantly lowered. Ultrafine calcium carbonate could effectively improve the tear strength, tensile strength, and modulus of the natural rubber latex film. The modulus increased with the increment of the calcium carbonate. When the content of calcium carbonate was less than 15%, the tear strength and tensile strength increased with the increments of calcium carbonate, but when the content was greater than 15%, the above‐mentioned properties decreased with the increment of calcium carbonate. By comprehensive consideration, the best reinforcing effect was obtained at a content of 15% ultrafine calcium carbonate. The particle diameters of calcium carbonate and their distribution in the calcium carbonate emulsion and in the rubber film were analyzed with SEM and a laser particle size tester, which showed that the distribution of calcium carbonate in the latex film was even and that it could effectively reinforce natural rubber latex film. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 982–985, 2003