bluuebunny/crossref_metadata_2025 huggingface dataset:
Formation of Aluminum Nitride Using Lithium Nitride as a Source of N3− in the Molten Aluminum Chloride
Authors: Sonoyama Noriyuki , Yasaki Yoichi , Sakata Tadayoshi
Published: May 2003

Synthesis of aluminum nitride, known as wide gap semiconductor, was attempted by the molten salt method using lithium nitride as the source of N3− ion and aluminum chloride as the source of aluminum ion and the medium of lithium nitride at 250 °C. Production of aluminum nitride was recognized from the spectra of XRD and XPS. Production of aluminum nitride suggests the simple reaction mechanism that the N3− ion ionize from lithium nitride in the molten aluminum chloride with Al3+ ion.
Alkylation of Benzene with Ethane over Platinum-loaded H-ZSM5 Catalyst
Authors: Kato Shinjiro , Nakagawa Kiyoharu , Ikenaga Na-oki , Suzuki Toshimitsu
Published: May 2003

Ethylbenzene was prepared from benzene and ethane, using platinum-loaded H-ZSM5 catalyst at 500°C, giving the ethylbenzene and styrene space time yields of 14.2 and 0.8 mmol h−1·g−1 of catalyst, respectively (benzene-based yields 6.9 and 0.4%).
Magnetic Enhancement of Electrochemical Current over Interdigitated Dot Electrodes
Authors: Rashkov Rashko S , Aogaki Ryoichi , Nakabayashi Seiichiro
Published: May 2003

Current over interdigitated dot electrodes increased under magnetic field. Mach-Zehnder laser interferometer revealed that the magnetic field tilted the fluid motion over the dot electrodes. This induced lateral movement enhanced the mass transport including redox cycling among the electrodes and consequently, the current.
A Novel Three-Dimensional Framework: Self-Assembly of AgNO3 and Pyrimidine
Authors: Cai Hu , Hu Huai-Ming , Chen Wan-Zhi , Zhu Hao-Guo , You Xiao-Zeng
Published: May 2003

The uncharged complex {Ag(pyrimidine)0.5NO3}∞ is prepared and characterized by X-ray diffraction studies which reveal a novel non-centrosymmetric three-dimensional (3-D) framework based both on the metal ions bound to ligands and anion bonding mode.
Facile Preparation of Robust Organic Gels by Cross-link of a Sugar-integrated Gelator by Toluene-2,4-diisocyanate
Authors: Inoue Kazuhiko , Ono Yoshiyuki , Kanekiyo Yasumasa , Kiyonaka Shigeki , Hamachi Itaru , Shinkai Seiji
Published: May 2003

Gelator 1 which has two aliphatic chains, three amide groups, and one glucosamine unit showed an excellent gelation ability for many organic solvents. The in situ cross-link of these organic gels by toluene-2,4-diisocyanate resulted in new robust gels with high Tgel values, retaining their gel fiber super-structure.
Acceleration of Photoinduced Electron Transfer in Porphyrin-Linked C70
Authors: Tamaki Koichi , Imahori Hiroshi , Nishimura Yoshinobu , Yamazaki Iwao , Shimomura Akihisa , Okada Tadashi , Sakata Yoshiteru
Published: May 2003

Porphyrin-linked C70 and porphyrin-linked C60 dyads have been designed and synthesized to evaluate the intrinsic properties of C70 in electron transfer. The photoinduced charge separation in the former is accelerated by a factor of about two compared with that in the latter. The result shows that C70 can be added to potential building blocks in artificial photosynthesis.
Evidence for the Importance of a Cationic Charge in the Formation of Hollow Fiber Silica from an Organic Gel System
Authors: Ono Yoshiyuki , Kanekiyo Yasumasa , Inoue Kazuhiko , Hojo Junichi , Shinkai Seiji
Published: May 2003

To obtain an insight into the mechanism for the construction of novel hollow fiber silica (“macaroni silica”), sol-gel polymerization of tetraethoxysilane was carried out in the organic gels prepared in the presence of a benzo-18-crown-6-containing cholesterol gelator. Hollow fiber silica was obtained only in the presence of the high concentration of KClO4. The findings support the view that the cationic charge plays a role indispensable to the construction of the tubular structure.
Formation of Trimethylpentanes from Isobutane and 1-Butene Catalyzed by Sulfated Metal Oxides
Authors: Satoh Kunihiko , Matsuhashi Hiromi , Arata Kazushi
Published: May 2003

The gas-phase alkylation of 1-butene with isobutane was carried out over superacids of sulfated metal oxides, SO4/Fe2O3, SO4/Al2O3, SO4/TiO2, SO4/SnO2, and SO4/ZrO2, at 0°C; SO4/SnO2 gave the highest yield of trimethylpentane (TMP). It was proved from relationship between the catalyst acidities and the yields of C8 paraffins that the first intermediate species was a t-butyl cation formed on the superacidic Lewis site by abstraction of H− followed by the alkylation with butenes to form TMP.
Photochemical Doping of TCNQ by Photoinduced Electron Transfer and C-C Cleavage of Radical Cation
Authors: Yokoi Hajime , Ishiguro Katsuya , Sawaki Yasuhiko
Published: May 2003

The irradiation with UV light (λ>350 nm) of mixed powder of tetracyanoqunodimethane (TCNQ) and donor (D–D) resulted in the formation of TCNQ−• indicating that TCNQ could be doped by irreversible photoinduced electron transfer and C–C cleavage of D–D+•.
Enzymatic Preparation of Malate-Based Polycarboxylates Having Higher Molecular Weights by Copolymerization with Lactone
Authors: Matsumura Shuichi , Beppu Hideki , Toshima Kazunobu
Published: May 2003

A strategy for increasing the molecular weight of malate-based polycarboxylates by the enzymatic polymerization of benzyl β-malolactonate (BML) with organic additives was studied. The lipase-catalyzed ring-opening polymerization of BML was significantly promoted by the addition of a small amount of β-propiolactone (PL) to yield polycarboxylates having an Mw of 32000 without a significant decrease in the inherent carboxy content.
Propane Oxidative Dehydrogenation over Nickel Supported on Sulfated Zirconia
Authors: Wang Shaobin , Murata Kazuhisa , Hayakawa Takashi , Hamakawa Satoshi , Suzuki Kunio
Published: May 2003

Excellent performance for the oxidative dehydrogenation of propane is achieved over lithium promoted nickel supported on sulfated zirconia, giving propylene selectivity of 50% at propane conversion of 20%.
An Artificial Signal Transduction System. Control of Lactate Dehydrogenase Activity Performed by an Artificial Cell-surface Receptor
Authors: Kikuchi Jun-ichi , Ariga Katsuhiko , Miyazaki Tatsuo , Ikeda Kouki
Published: May 2003

A supramolecular bilayer assembly as an artificial signaling system was constituted in combination with a steroid cyclophane as an artificial receptor, an NADH-dependent lactate dehydrogenase as an effector, and a bilayer-forming peptide lipid. Signal transduction from the receptor to the effector was observed for the present hybrid system by employing two kinds of signaling species, 1-hydroxy-2-naphthaldehyde as an external signal and a Cu(II) ion as a signal transmitter.
The Enantioselective Chalcogeno-Baylis-Hillman Reaction Using a Chiral Hydroxy Chalcogenide-TiCl4 Complex
Authors: Kataoka Tadashi , Iwama Tetsuo , Tsujiyama Shin-ichiro , Kanematsu Kiyoko , Iwamura Tatsunori , Watanabe Shin-ichi
Published: May 2003

The enantioselective chalcogeno-Baylis-Hillman reaction was investigated by the use of chiral hydroxy chalcogenides in the presence of TiCl4 under atmospheric pressure. The best result was obtained with 10-methylthioisobornenol as a chiral hydroxy chalcogenide.
Catalytic Asymmetric Acylation of Racemic Secondary Alcohols with Benzoyl Chloride in the Presence of a Chiral Diamine
Authors: Sano Tomohumi , Imai Keisuke , Ohashi Kousaburo , Oriyama Takeshi
Published: May 2003

Nonenzymatic kinetic resolution of racemic secondary alcohols is an efficient synthetic method to obtain optically active compounds in organic chemistry. Catalytic asymmetric acylation of racemic secondary alcohols has been successfully performed with achiral benzoyl chloride in the presence of only 0.3 mol% of chiral diamine (3) derived from (S)-proline, combined with 0.5 equivalent of triethylamine. This asymmetric acylation of various racemic cyclic secondary alcohols, 5, 6, or 8 membered cycloalkanols (1a–1c), hydroxyesters (1d and 1e), and bromohydrins (1f and 1g) gave the corresponding optically active benzoates (84–97% ee) and unreacted alcohols (79–95% ee). Racemic acyclic secondary alcohols (1h–1j) were also acylated in moderate enantioselectivity.
Novel Dehydrative Glycosylation by Using Acid Anhydride and TMSClO4
Authors: Wakao Masahiro , Nakai Yoshihiko , Fukase Koichi , Kusumoto Shoichi
Published: May 2003

Novel dehydrative glycosylation with 1-hydroxy sugars as glycosyl donors was achieved. Combination of trifluoroacetic anhydride or trichloroacetic anhydride as dehydrating agents with TMSClO4 as a Lewis acid afforded desired glycosides in good yields. t-Butyldiphenylsilyl and trichloroethoxycarbonyl groups at the 6-position of donors enhance α-selectivity of the glycosylation.
Molecular Imprinting in Hydrogen Bonding Networks of Polyamide Nylon for Recongnition of Amino Acids
Authors: Reddy P Sreenivasulu , Kobayashi Takaomi , Fujii Nobuyuki
Published: May 2003

Molecularly imprinted Nylon-6 was prepared from the polymer solution of formic acid having l-glutamine template. The recognition of amino acids by l-glutamine imprinted-polymer was evaluated by binding experiments for l-glutamine and its analogues. It was revealed that the recognition was effective for l-glutamine by the imprinted polymer as compared with its racemate d-glutamine and l- or d-glutamic acid.
A Mercurated Azobenzene Complex for Photoswitching between trans and cis Forms
Authors: Barigelletti Francesco , Ghedini Mauro , Pucci Daniela , Deda Massimo La
Published: May 2003

A pro-mesogenic compound based on an ortho-mercurated derivative of the azobenzene chromophore undergoes reversible trans-cis photoisomerization. By exploiting the spectral features of the orthometalated cis and trans isomers it is possible to produce photostationary states containing 78 and 90% of trans (rod-like, bright yellow) and cis (bent, colourless) isomers, respectively, which may be the basis for an efficient all-optical control of ON/OFF liquid crystalline behaviour.
A Simple and Rapid Protocol for N-Methyl-α-Amino Acids
Authors: Reddy G Vidyasagar , Iyengar DS
Published: May 2003

A two step strategy for optically pure N-Protected-N-methyl-α-amino acids starting from N-protected-α-amino acids via reductive cleavage of oxazolidinones using NaCNBH3/TMSCl is described.
The First Unequivocal Observation of Dynamic Solvent Effects in the Thermal Geometrical Isomerization of 3,3′-Diethyloxadicarbocyanine Iodide (DODCI)
Authors: Kim Jong Chul , Ohga Yasushi , Asano Tsutomu
Published: May 2003

Pressure dependence of the rate of thermal geometrical isomerization of 3,3′-diethyloxadicarbocyanine iodide (DODCl) was studied in ethanol and in a highly viscous hydroxylic solvent, 2-methyl-2,4-pentanediol. The kinetic effects of pressure in the two solvents are qualitatively different and the results strongly suggest that the stochastic analysis of the kinetic results in 1-alkanols reported earlier needs to be renounced.
Hydrothermal Synthesis of Fe-montmorillonite in Si-Fe-Mg System
Authors: Nagase Takako , Iwasaki Takeshi , Ebina Takeo , Hayashi Hiromichi , Onodera Yoshio , Dutta Niranjan Chandra
Published: May 2003

Fe-montmorillonite (Na0.3Fe3+1.7Mg0.3Si4O10(OH)2·H2O) was synthesized hydrothermally for 24 hours at 100 and 200 °C. XRD analysis showed the synthesized material to be crystalline Fe-montmorillonite without impurities, with d001=11-14.3 Å and d06=1.52-1.53 Å, respectively. The particle size of the material was found to be > 500 Å by TEM. The X-ray photoelectron binding energy of Fe indicated that iron is present in smectite as Fe3+.
Silver or Copper Triflate-Catalyzed Amination of Silyl Enol Ethers
Authors: Kobayashi Shu , Yamashita Yasuhiro , Ishitani Haruro
Published: May 2003

Amination of silyl enol ethers with azo diester compounds proceeded smoothly in the presence of a catalytic amount of AgOTf or Cu(OTf)2. Various types of silyl enol ethers reacted smoothly under these conditions and AgOTf gave better yields than Cu(OTf)2 in most cases.
UV-visible Slab Optical Waveguide Spectroscopy of Cytochrome c Adsorbed on a Liquid-Solid Interface
Authors: Kato Kenji , Takatsu Akiko , Matsuda Naoki
Published: May 2003

A slab optical waveguide spectroscopy (SOWG spectroscopy) was applied to the UV-visible absorption spectroscopy. The SOWG with quartz core layer and amorphous fluorocarbon polymer clad layer has good transparency in UV-visible light region. It was demonstrated that adsorption process on the SOWG surface of cytochrome c was successfully observed in situ.
Diethylaluminum Ethoxide Mediated Stereoselective Diels-Alder Reaction of α,β-unsaturated Ketones and Acetoxy-1,3-butadienes as Diene Components
Authors: Shibata Jun , Shiina Isamu , Mukaiyama Teruaki
Published: May 2003

Stereoselective Diels-Alder reaction between several α,β-unsaturated ketones and acetoxy-1,3-butadienes is effectively performed by the promotion of diethylaluminum ethoxide under mild conditions. This reaction is successfully applied to the synthesis of optically active bicyclo[6.4.0]dodecanone 9 which corresponds to the BC ring system of 10-deoxy taxane derivatives from the 8-membered ring enone 7 and diene 2.
Construction of the Tetranuclear Complex with Inter- and Intramolecular Stacking-Like Arrangement Composed of Planar Palladium(II) Units
Authors: Yamada Yasunori , Okamoto Ken-ichi
Published: May 2003

The reaction of a square-planar S-donating metalloligand [Pd(aet)2] (aet = 2-aminoethanethiolate) with [Pd(NO3)2(bpy)] (bpy = 2,2′-bipyridine) gave a new type of S-bridged tetranuclear complex [Pd4(aet)4(bpy)2]4+ (1), in which two {Pd(bpy)} moieties are aligned so as to overlap each other by bridging with two [Pd(aet)2] units.
Tetrathiafulvaleno-quinonemethides and -thioquinonemethides
Authors: lwamatsu Masaki , Kominami Tsuyoshi , Ueda Kazumasa , Sugimoto Toyonari , Fujita Hideo , Adachi Tomohiro
Published: May 2003

Novel donor/acceptor-type tetrathiafulvalenes, tetrathiafulvaleno-quinonemethide and -thioquinonemethide were synthesized, which are expected as new π donor molecules bearing d local spin, because they can capture several magnetic metal ions through binding with the carbonyl oxygen or thiocarbonyl sulfur atom.
Donor-Acceptor Type Superconductor, (BETS)2(Cl2TCNQ)
Authors: Kondo Ryusuke , Hasegawa Tatsuo , Mochida Tomoyuki , Kagoshima Seiichi , Iwasa Yoshihiro
Published: May 2003

It was found that (BETS)2(Cl2TCNQ) is an all-organic superconductor, where BETS is bis(ethylenedithio)tetraselenafulvaleneand Cl2TCNQ is 2,5-dichlorotetracyanoquinodimethane.The superconducting critical temperature was 1.3 K ± 0.3 K under pressure.
Immobilization of a C2-Symmetric ansa-Zirconocene Complex on Silica Surfaces Using a Si-Cl Anchor: Catalysts for Isospecific Propene Polymerization
Authors: Suzuki Noriyuki , Asami Hayato , Nakamura Takashi , Huhn Thomas , Fukuoka Atsushi , Ichikawa Masaru , Saburi Masahiko , Wakatsuki Yasuo
Published: May 2003

A C2-symmetric ansa-zirconocene complex which has a Si-Cl moiety on its bridge was immobilized on SiO2 by the reaction of the Si-Cl anchor with Si-OH on the solid surface. The prepared solid catalyst was found to be effective for isospecific propene polymerization. It exhibited higher productivity compared to a catalyst prepared using the zirconocene without a Si-Cl anchor. The effect of pretreatment of silica surfaces with Me3SiCl on catalyst performance is also described.
Polytopic Coreceptor from Conformationally Stabilized Calix[6]arene for Alkali Metal Ions
Authors: Zhou Jinwei , Kawanishi Yuji , Zhang Yan , Yuan Hushan , Huang Zhitang
Published: May 2003

1:4 and 1:3 complexes of a conformationally stabilized calix[6]arene with NaI and KI were detected by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) for the first time.
Polymerization of Alkyl Methacrylate Catalyzed by Hydridorhenium Complexes
Authors: Komiya Sanshiro , Chigira Tomoko , Suzuki Toru , Hirano Masafumi
Published: May 2003

Hydridorhenium complexes having dimethylphenylphosphine ligands such as ReH(N2)(PMe2Ph)4, ReH(C2H4)2(PMe2Ph)3, ReH(PMe2Ph)5, ReH3(PMe2Ph)4, ReH5(PMe2Ph)3 smoothly induce polymerization of alkyl methacrylate in halogenated solvents such as dichloromethane, dichloroethane, chloroform, carbon tetrachloride, and dibromomethane at 30 °C.
Photochemical Reduction of NADP+ by Zinc Protoporphyrin Reconstituted Myoglobin as a Simple Model of Photosystem I
Authors: Nishiyama Katsuhiko , Uchiyama Miho , Mie Yasuhiro , Taniguchi Isao
Published: May 2003

Photoinduced electron transfer between zinc protoporphyrin reconstituted myoglobin (Zn-Mb) and NADP+ functions as a model of photosystem I by forming NADPH. The reduction efficiency of NADP+ depended strongly on the solution pH, which was explained by the difference in the redox potential and/or the static interaction between Zn-Mb and a sacrificial donor triethanolamine (TEA).
Geminal Bond Participation in the Cope Rearrangements of Z- and E-Substituted 1,5-Hexadienes and in the Reverse Reactions
Authors: Ikeda Hirotaka , Naruse Yuji , Inagaki Satoshi
Published: May 2003

We analyzed the bond interactions at the transition state of the Cope rearrangement of 1,5-hexadiene to disclose the significant participation of the geminal σ bonds at the reacting centers. The electron-donating σ bonds at the Z-positions and the electron-accepting σ bonds at the E-positions in the 1-substituted 1,5-hexadienes were predicted from the geminal bond participation to enhance the reactivities. For the reverse reactions, the 3-substituted 1,5-hexadienes were similarly predicted to rearrange more readily into the 1-substituted ones with the electron-donating σ bonds at the Z-positions. The predictions were confirmed by the density functional theory calculations.
A Layer-by-Layer Deposition of Concanavalin A and Native Glucose Oxidase to Form Multilayer Thin Films for Biosensor Applications
Authors: Anzai Jun-ichi , Kobayashi Yuka , Hoshi Tomonori , Saiki Hidekazu
Published: May 2003

Glucose oxidase (GOx) can be assembled into multilayer thin films without any chemical modification, by an alternate deposition of Concanavalin A (Con A) and native GOx on the surface of electrode. The Con A/GOx multilayer film-modified platinum electrodes functioned as a glucose biosensor.
Compositional and Carbon Isotopic Behavior of C19 and C20 Isoprenoid Hydrocarbons Produced by Laboratory Heating of Phytol: A Study of Formation of Pristane and Phytane from Chlorophylls on Diagenesis
Authors: Ishiwatari Mariko , Yamada Keita , Ishiwatari Ryoshi
Published: May 2003

Carbon isotopic ratios (δ13C) of isoprenoid hydrocarbons (isops) produced by heating (300-350 °C) of phytol were measured for understanding diagenetic reaction of chlorophylls. C19 isop was isotopically lighter than the phytol at the early stage of the heating and lighter than C20 isop regardless of heating temperature and time. Difference in δ13C between C19 and C20 isops observed in this study was similar to that observed for some petroleum.
Synthesis of Pyrrole Derivatives by the Heck-Type Cyclization of γ,δ-Unsaturated Ketone O-Pentafluorobenzoyloximes
Authors: Tsutsui Hironori , Narasaka Koichi
Published: May 2003

Substituted pyrroles are synthesized from γ,δ-unsaturated ketone O-pentafluorobenzoyloximes by the intramolecular Heck-type amination of the olefinic moiety catalyzed by Pd(PPh3)4.
Enclathrated Solvent Effects on the Photochromic Process of N-Salicylideneaniline in the Crystal State
Authors: Kawato Toshio , Kanatomi Hajime , Amimoto Kiichi , Koyama Hiroyuki , Shigemizu Hideki
Published: May 2003

N-{3,5-bis(1-methyl-1-phenylethyl)salicylidene}-4-tritylaniline and its clathrate crystals with methanol and acetone were prepared. Solvent effects were observed on the solid-phase photoisomerization of the Schiff base.
Stereospecific Total Synthesis of Amberketal and a Homologue
Authors: Kongkathip Boonsong , Kongkathip Ngampong , Janthorn Sirinan , Virarangsiyakorn Duangmanee
Published: May 2003

Amberketal (1a) and acetal homologue (2a) have been synthesised from a commercially available methyl acetoacetate involving palladium catalysed cyclisation as a key step.
Intracellular Responses of Hybrid Liposomes against Leukemia Cells Related to Apoptosis with Antitumor Activity
Authors: Matsumoto Yoko , Kato Toshihiro , Kemura Yoshinori , Tsuchiya Makoto , Yamamoto Megumi , Ueoka Ryuichi
Published: May 2003

Intracellular responses of hybrid liposomes against leukemia cells related to apotosis were observed for the first time along with the highly inhibitory effects.
Synthesis, X-Ray Structures, and Magnetic Properties of [Cu2(piv)4(Et3N)2] and [Cu6(piv)6(EtO)6] (Hpiv = Pivalic Acid): Role of Base for Dinuclear Adduct and Oligonuclear Formation
Authors: Mikuriya Masahiro , Azuma Hiroshi , Nukada Ryoji , Handa Makoto
Published: May 2003

Copper(II) pivalate adduct with triethylamine, [Cu2(piv)4(Et3N)2] (Hpiv = pivalic acid), and cyclic hexanuclear copper(II) complex, [Cu6(piv)6(EtO)6], have been synthesized and characterized by X-ray crystallography and magnetic susceptibility measurement.
The Effect of Humic Substances on Pb(II) Adsorption on Vermiculite
Authors: Jelinek Ludek , Inoue Katsutoshi , Miyajima Tohru
Published: May 2003

Adsorption of lead ion from aqueous solutions containing humic substances on vermiculite was investigated. Humic substances exhibited a strong influence on lead adsorption on vermiculite. The adsorption of humic acids on vermiculite plays an important role in lead ion distribution between the clay mineral and aqueous solution. There are remarkable differences in adsorption behaviors of humic acid itself among the humic acids taken from different origins. Adsorption behaviors of lead from aqueous solution containing fulvic acids were found to be less dependent on their origins, which may be attributable to negligible adsorption of fulvic acids on vermiculite.
Absolute Quantum Yields and Lifetimes of Photosensitized Phosphorescence of Singlet Oxygen O2 (1Δg) in Air-Saturated Aqueous and Organic Solutions of Phenalenone
Authors: Shimizu Okiyasu , Watanabe Jun , Imakubo Keiichi , Naito Shizuo
Published: May 2003

The absolute quantum yield ΦP of singlet oxygen (1O2) phosphorescence sensitized by phenalenone (PH) was determined together with the lifetime τ in 19 different solvents, using the known ΦP = (1.38 ± 0.05) × 10−3 in CCl4 as a standard. Measurements of both ΦP and τ were performed by combined use of a pulsed laser and a photon-counter coupled with a near-IR-sensitive photomultiplier. The ΦP value in water was determined to be ΦP = (4.5 ± 0.2) × 10−8.
Synthesis of Novel Cyclodextrin Derivatives Having Oligosaccharide Cluster
Authors: Furuike Tetsuya , Aiba Seiichi
Published: May 2003

A simple and facile method for the synthesis of novel 6-persubstituted β-cyclodextrin derivatives having a sugar cluster through a spacer arm is described. The coupling reaction of per-6-iodo-β-CD with each derivative of d-galactose (Gal) or N-acetyl-d-glucosamine (GlcNAc) smoothly proceeded and gave the corresponding cyclodextrin derivatives having seven sugar residues in excellent yields.
Oligomerization of Aromatic Tertiary Amines
Authors: Sato Hisaya , Kanegae Aiko , Yamaguchi Ryoji , Ogino Kenji , Kurjata Jan
Published: May 2003

The oligomerization of some tertiary aromatic amines was studied using ferric chloride in a variety of solvent. The predominant dimer formation of triphenylamine (TPA) was observed in chloroform at 0 °C where concentration of TPA was 0.125 mmol/l and the molar ratio of ferric chloride to TPA was 4. Except for N-methyldiphenylamine, high molecular weight oligomers were formed in a variety of solvents.
Electrochemical Measurement of Dissolved Oxygen from Atmosphere under a Magnetic Field Gradient
Authors: Kishioka Shin-ya , Aogaki Ryoichi
Published: May 2003

Electrochemical measurement using a steady state voltametry with a microdisk electrode revealed the effect of magnetic field on the acceleration of the dissolution of the atmospheric oxygen molecule into water containing tetraethylammonium-perchlorate as a supporting electrolyte in the initial state.
Enhancement of Diastereomer Selectivity Using Highly-Oriented Polymer Stationary Phase
Authors: Ihara Hirotaka , Sagawa Takashi , Nakashima Ken-ichi , Mitsuishi Kayoko , Goto Yoshihiro , Chowdhury Jamil , Sakaki Shigeyoshi
Published: May 2003

Enantiomer separation has been often realized with reversed phase liquid chromatography using diastereomerizing reagents with simply-hydrophobized silica. The present study demonstrates that diastereomer selectivity can be enhanced through highly-oriented organic phase produced by achiral poly(octadecyl acrylate)-grafted on silica and a carbonyl-π interaction due to the acrylate moiety is effective as the driving force for the selectivity enhancement.
Photoinduced Color Change of Methylviologen in Polycyano-Polycadmate Host Clathrates
Authors: Yoshikawa Hirofumi , Nishikiori Shin-ichi
Published: May 2003

A series of polycyano-polycadmate host clathrates accommodating a methylviologen dication and an organic molecule has been prepared. Some of them showed a color change from white to blue under UV-VIS light, which comes from the reduction of the methylviologen dication to its monocation radical. This phenomenon depends on the species of the coexistent organic guest and the crystal structure of the clathrates.
Structural Requirements of Zinc Porphyrin Derivatives on the Complex-Forming with Light-Harvesting Polypeptides
Authors: Kashiwada Ayumi , Watanabe Hiroyuki , Mizuno Toshihisa , Iida Kouji , Miyatake Tomohiro , Tamiaki Hitoshi , Kobayashi Masami , Nango Mamoru
Published: May 2003

Zn-bacteriochlorins or Zn-mesoporphyrins were successfully assembled with light-harvesting (LH)-α and -β polypeptides separately isolated from photosynthetic bacteria in n-octyl-β-d-glucopyranoside (OG) micelle, depending on the structure of Zn-porphyrin derivatives and on temperature.
Photoswitching of Intramolecular Magnetic Interaction: A Diarylethene Photochromic Spin Coupler
Authors: Matsuda Kenji , Irie Masahiro
Published: May 2003

We have designed and synthesized 1,2-bis[6-(1-oxyl-3-oxide-4,4,5,5-tetramethylimidazolin-2-yl)-2-methylbenzo[b]thiophen-3-yl]hexafluorocyclopentene which shows photoswitching of intramolecular magnetic interaction by incorporating two nitronyl nitroxide into diarylethene photochromic spin coupler.
Synthesis and Crystal Structure of a Water-soluble, Anionic Octanuclear Silver(I) Cluster Formed by 2-Mercaptobenzoic Acid (H2mba); K12[Ag8(mba)10]·12H2O
Authors: Nomiya Kenji , Noguchi Ryusuke , Kato Chieko
Published: May 2003

We have prepared a novel water-soluble silver(I) complex showing effective antibacterial activities K12[Ag8(mba)10]·12H2O (1a, H2mba = 2-mercaptobenzoic acid) from the Ag2O : H2mba : KOH = 1 : 4 : 8 molar ratio reaction in aqueous media and determined its crystal structure. The X-ray crystallography revealed that 1a was a discrete, anionic octanuclear silver(I) cluster consisting of two butterfly-type Ag4S4 subunits bridged by two µ3-S atoms.
Atomic Force Microscopy of Photolysis of Azobisisobutyronitrile in the Solid State
Authors: Zeng Qingdao , Wang Chen , Bai Chunli
Published: May 2003

The formation of regular nanostructures by photolysis of azobisisobutyronitrile (AIBN) in the solid state is investigated using atomic force microscopy (AFM) and known crystal packing data. AFM reveals that the crystal face (001) of AIBN yields both craters and volcanoes. All the experimental results are correlated with the crystal structure. Molecular interpretation of the AFM features of AIBN is given.
Double Acylation of Alkenes with Acylchromates Promoted by Cationic Pd(II) Complex
Authors: Yamane Motoki , Ishibashi Yuichiro , Sakurai Hidehiro , Narasaka Koichi
Published: May 2003

Double acylation of alkenes such as norbornene and vinylsilane proceeds by the use of acylchromate complexes and a cationic Pd(II) complex. When two different acylchromates are added successively to a mixture of alkene and the Pd complex, unsymmetrical diketones are obtained almost selectively.
A New Mercurophilic Troponoid Tetrathiacyclophane; 2,6,8,12-Tetrathia-1(2,7),7(2,7)-ditropona-4(1,3),10(1,3)-dibenzenacyclododecaphane
Authors: Mori Akira , Kubo Kanji , Nishimura Tatsuya , Kato Nobuo , Takeshita Hitoshi
Published: May 2003

Condensation reaction of 2,7-dibromotropone with 1,3-bis(mercaptomethyl)benzene afforded 2:2- and 1:2-condensates. Their structures were determined to be new troponoid tetrathiacyclophanes by X-ray crystallographic analyses; 2:2-condensate had a 1,2-alternate conformation and was well-stacked through π-π interactions. 1:2-Condensate had approximately a cone conformation. 2:2-Condensate formed a complex with Hg(II) ion.
A Direct and Selective Syntheses of α,α-Dichloro- and α-Chloro-ethyl Ketones by the Reaction of Alkyl Carboxylates with 1,1-Dichloroethyllithium
Authors: Shiina Isamu , Imai Yumiko , Kagayama Akifumi , Mukaiyama Teruaki
Published: May 2003

1,1-Dichloroethyllithium (5), generated by treating 1,1-dichloroethane (4) with lithium diisopropylamide (LDA) or n-butyllithium, reacted with alkyl carboxylates to afford the corresponding α,α-dichloro- or α-monochloro-ethyl ketones selectively in good to high yields. According to the above alkylation method, synthetic intermediates of Taxol, optically active α,α-dichloroethyl polyoxyketone 2 and α-chloroethyl polyoxyketone 3, were respectively synthesized from optically active methyl polyoxycarboxylate 1 in good yields.
Highly Efficient Catalytic Activity of Lanthanide(III) Ions for Conversion of Saccharides to 5-Hydroxymethyl-2-furfural in Organic Solvents
Authors: Seri Kei-ichi , Inoue Yoshihisa , Ishida Hitoshi
Published: May 2003

All lanthanide(III) ions were found to catalyze dehydration of saccharides to 5-hydroxymethyl-2-furfural (HMF) in DMSO at 100 - 120 °C. Particularly, d-fructose was almost quantitatively converted to HMF without generating any byproducts. The results of the reaction with di- and trisaccharides indicated that the d-fructose moiety in the substrates was selectively converted to HMF.
A Thirty-Membered Macrocyclic Binuclear Metal Complex: Synthesis and Structural Characterization of [Ag2(psb)2]2+ {psb = 1,2-Bis[(4-pyridinyl)sulfanylnlethyl]benzene}
Authors: Zhao Yingjun , Hong Maochun , Su Weiping , Cao Rong , Zhou Zhongyong , Chan Albert S C
Published: May 2003

A neutral exo-pyridino-bidentate ligand, 1,2-bis[(4-pyridinyl)sulfanylmethyl]benzene (psb), was prepared from the reaction of 1,2-bis(bromomethyl)benzene and sodium pyridine-4-thiolate for metal complex syntheses. The reaction of silver salt and psb resulted in binuclear complex [Ag2(psb)2](ClO4)2 with a thirty-membered macrocycle, in which the length is 2.0 nm.
Utility of i-Steroid-Route to Oxidized Sterol Bound to a Cross-linker: Synthesis of the Steroid Antigen
Authors: Kim Byung Ju , Morita Hiroyuki
Published: May 2003

The target sterol, which was for preparation of oxidized sterol antigen to apply to a new antibody diagnostic method for circulatory disease, was successfully synthesized via  i-steroid transformation as followings: 1) the Grignard reaction, 2) Barton-McCombie reaction, 3) regioselective photolytic-addition of thiolacetic acid toward 25-double bond, and 4) in situ Michael addition between the thiol and a cross-linker.
The Synthesis of a Reconstituted C60-Modified Protein
Authors: Murakami Hiroto , Okusa Yuko , Kiyonaka Shigeki , Hamachi Itaru , Shinkai Seiji , Nakashima Naotoshi
Published: May 2003

We designed and synthesized reconstituted C60-modified myoglobin (C60-Mb) and found that fundamental characteristics, except autoxidation rate constants, of C60-Mb and native Mb were almost identical.
Mild, Efficient and Selective Nitration of Anilides, Non-Activated and Moderately Activated Aromatic Compounds with Ammonium Molybdate and Nitric Acid as a New Nitrating Agent
Authors: Sana Sariah , Rajanna K C , Ali Mir Moazzam , Saiprakash P K
Published: May 2003

Ammonium molybdate [Mo(VI)] is operationally simple, environmentally safe and inexpensive reagent. Regioselective nitration of anilides, non-activated and moderately activated aromatic compounds could be afforded by employing ammonium molybdate and nitric acid as mild and effective nitrating agent. This procedure works efficiently under reflux conditions to prepare mononitroderivatives of anilides, non-activated and moderately activated aromatic compounds in good to excellent yield with high regioselectivity.
A Novel Fluorescent Dicarboxylic Acid, (Z)-1,7-Nonadecadiene-2,3-dicarboxylic Acid, Produced by White-Rot Fungus Ceriopsis subvermispora
Authors: Enoki Makiko , Watanabe Takashi , Honda Yoichi , Kuwahara Masaaki
Published: May 2003

A novel fluorescent dicarboxylic acid bearing a long alkenyl side chain, (Z)-1,7-nonadecadiene-2,3-dicarboxylic acid, was isolated from cultures of a white-rot fungus Ceriporiopsis subvermispora. This is the first report of a microorganism that produces an amphiphilic itaconic acid derivative with a long aliphatic side chain.
Calix[n]arenes Provided with Thiols for Modified Electrode Applications; Ring-size Dependent Voltammetric Behavior toward Ferrocene Derivatives
Authors: Nakano Koji , Tanaka Sachiko , Takagi Makoto , Shinkai Seiji
Published: May 2003

Calix[n]arenes (n = 4, 6) adlayers formed by thiol-aided self-assembly showed calixarene ring-size distinctive voltammetric behavior to water-soluble ferrocene derivatives. Computer simulations of the cyclic voltammetric i-E responses were made and parameters for the electrode reaction were discussed.
Synthesis and Structure of a Diselenido-Bridged Dinuclear Ruthenium Complex [{RuCl(P(OMe)3)2}2(μ-Se2)(μ-Cl)2]
Authors: Mizutani Jun , Matsumoto Kazuko
Published: May 2003

A diselenido-bridged dinuclear ruthenium complex, [{RuCl(P(OMe)3)2}2(μ-Se2)(μ-Cl)2] was synthesized by the reaction of trans-[RuCl2{P(OMe)3}4] and red amorphous selenium. A single crystal X-ray structure analysis showed that the topological geometry was the same as that of the disulfido analogue. The Ru-Se and Se-Se lengths are longer than the corresponding ones in the disulfido analogue according to the difference between the covalent radii of sulfur and selenium. Electrochemical measurement indicated that the title complex undergoes electrical reduction and subsequent chemical reaction.
Photoreduction of Self-Assembled Lipidporphyrinato-iron(III) Chloride with Hyaluronic Acid under Semi-Physiological Conditions
Authors: Komatsu Teruyuki , Yanagimoto Tetsuya , Nakagawa Akito , Tsuchida Eishun
Published: May 2003

Photoirradiation into the LMCT band (λmax: 362 nm) of self-assembled amphiphilic tetraphenylporphyrinato-iron(III) (lipidporphyrinato-iron(III)) chloride with hyaluronic acid leads to reduction of the central ferric ion in saline solution (pH 7.4, 25 °C); the obtained lipidporphyrinato-iron(II) can reversibly bind and release dioxygen.
An Energy Model for Bifurcation Analysis of a Double-Notched Concrete Panel: Simplified Model
Authors: Chen G. , Baker G.
Published: May 2003

The uni-axial tension of a double-notched concrete panel is analyzed. The unsymmetrical crack propagation is treated as a bifurcation problem. The concept of minimization of the second-order energy is used as the criterion for the bifurcation from symmetrical crack propagation to unsymmetrical crack propagation. In order to study the decisive factors affecting bifurcation, a simplified softening model is adopted where the cracked material is represented by softening rods, and un-cracked material by elastic rods. The influences on bifurcation of the crack plane dimension, the material cohesiveness, and the local constitutive law are analyzed. The analysis shows that the unsymmetrical crack propagation (i.e. strains localizing on one side of the specimen) may occur either before or after the peak load. Whether the unsymmetrical crack propagation occurs before the peak load or not depends on the ratio of the cracked length to un-cracked ligament. Shear stiffness does not have a significant influence on crack propagation before the peak load; however, it does determine whether the unsymmetrical crack propagation arises after the peak load.
The Damping Analysis of Experimental Concrete Beams under Free-Vibration
Authors: Salzmann A. , Fragomeni S. , Loo Y. C.
Published: May 2003

This paper presents an overview of the free-vibration damping analysis technique commonly employed by laboratories to determine the amount of material damping contained by a concrete specimen. From laboratory investigations the difficulties associated with a technique often employed for the extraction of damping from the free-vibration decay curve are identified. Extensive free-vibration tests undertaken on a wide variety of concrete beams indicate that for the traditional logdec technique, damping is to be extracted from the optimal peak ratio ( An/A1) region of the free-vibration decay curve. An analysis of the effect of experimental test variables; hammer weight and hammer excitation position, on the calculation of damping is undertaken. The results show that neither test variable produces measurable impact on the calculation of damping.
Chiari I malformation and cloacal exstrophy: Report of a patient with both defects of blastogenesis
Authors: Tubbs R. Shane , Smyth Matthew D. , Oakes W. Jerry
Published: May 2003

We report on child with Chiari I malformation (CIM) and cloacal exstrophy, a combination of findings that has not been reported previously. CIM and cloacal exstrophy both demonstrate abnormalities that represent maldevelopment of the midline field. This combination of anomalies in this patient suggests an impairment of midline development during blastogenesis. © 2003 Wiley‐Liss, Inc.
IL‐1α (− 889) promoter polymorphism is a risk factor for osteomyelitis
Authors: Asensi Víctor , Alvarez Victoria , Valle Eulalia , Meana Alvaro , Fierer Joshua , Coto Eliecer , Carton José Antonio , Maradona José Antonio , Paz José , Dieguez Maria Angeles , Fuente Belén de la , Moreno Alfonso , Rubio Silvino , Tuya Maria José , Sarasúa Julián , Llames Sara , Arribas José Manuel
Published: May 2003

As osteomyelitis (OM) induces the synthesis of inflammatory cytokines and IL‐1 mediates bone resorption by osteoclasts we determined if there is an association between certain common polymorphisms of the genes encoding proinflammatory cytokines (IL‐1α and β, IL‐6, TNF‐α) and OM in adults. The IL‐1α (− 889) TT genotype was significantly more frequent among 52 OM patients than in 109 healthy controls (13/52, [25.0%] vs. 9/109, [8.3%], P = 0.0081, χ2 = 7.01, OR = 3.7, 95% CI, 1.35–10.34). Patients who were homozygous for the T allele were younger than the rest of the OM patients (mean age 35.7 ± 11.5 vs. 58.1 ± 18.6 years, P = 0.001). IL‐1β TT (+ 3953) polymorphism was also more frequent in OM patients (P = 0.014, χ2 = 5.12, OR = 5.1, 95% CI, 1.21–52.14), but IL‐1β is in linkage disequilibrium with the IL‐1α *T (P < 0.001). Route of infection, chronicity of the infection, type of microorganism isolated, and frequency of relapses were similar in patients with and without the IL‐1α TT genotype. There were no associations between OM and polymorphisms of other cytokines genes. IL‐1α serum levels were significantly increased in all the OM patients independently of their IL‐1 genotype compared to the controls (P = 0.021). Although IL‐1α serum levels were not significantly higher in patients with the IL‐1α (− 889) polymorphism, this does not exclude a difference in production of IL‐1α by osteoclasts or other inflammatory cells at the site of infection. © 2003 Wiley‐Liss, Inc.
Carboranyl derivatives of amineboranes and boron analogs of esters: a synthetic investigation
Authors: Rana Geeta , Vyakaranam Kamesh , Ledger Sarah C. , Delaney Shannon L. , Maguire John A. , Hosmane Narayan S.
Published: May 2003

New functionalized carboranyl derivatives of amineboranes and boron analogs of esters are reported. The reaction of 1,12‐(aminopropyl)‐1,12‐dicarbadodecaborane (2), 2‐(aminopropyl)‐1,2‐dicarbadodecaborane (4), 1‐methyl‐2‐(aminopropyl)‐1,2‐dicarbadodecaborane (6), 1‐phenyl‐2‐(aminopropyl)‐1,2‐dicarbadodecaborane (8) with Me3NBH2X produced novel carboranylamineboranes of the general formula 1,12‐[(CH2)3NH2BH2X]2‐1,12‐C2B10H10 [X = CN (2a), COOCH3 (2b), CONHEt (2c), CONHCH(CH2C6H5)COOCH3 (2d), CONHCH(CH3)COOCH3 (2e), CONHCH[CH(CH3)2]COOCH3 (2f), CONHCH(CH2C6H4OH)COOCH3 (2g), 1‐CH2NH2BH2CN (2h)] or 1‐R‐2‐[(CH2)3NH2BH2X]‐1,2‐C2B10H10 {R = H, X = CN (4a), COOCH3 (4b), CONHEt (4c), COOH (4d); R = CH3, X = CN (6a), COOCH3 (6b), CONHCH(CH2C6H5)COOCH3 (6c), CONHCH(CH3)COOCH3 (6d), CONHCH[CH(CH3)2]COOCH3 (6e), CONHCH(CH2C6H4OH)COOCH3 (6f); R = C6H5, X = CN (8a), COOCH3 (8b), CONHCH(CH2C6H5)COOCH3 (8c), CONHCH(CH3)COOCH3 (8d), CONHCH[CH(CH3)2]COOCH3 (8e), CONHCH(CH2C6H4OH)COOCH3 (8f)} by the amine exchange reaction. The reaction of 1‐(aminomethyl)‐1,2‐dicarbadodecaborane with Me3NBH2X (X = CN) produced 1‐[CH2NH2BH2CN]‐1,2‐C2B10H10 (2h). Compounds 2a, 4a, 6a, and 8a were also synthesized by the reaction of 1,12‐(aminopropyl)‐1,12‐dicarbadodecaborane hydrochloride (1), 2‐(aminopropyl)‐1,2‐dicarbadodecaborane hydrochloride (3), 1‐methyl‐2‐(aminopropyl)‐1,2‐dicarbadodecaborane hydrochloride (5), 1‐phenyl‐2‐(aminopropyl)‐1,2‐dicarbadodecaborane hydrochloride (7) with sodium cyanoborohydride. The reaction of Li2[1,2‐CO2‐1,2‐C2B10H10] (9) or Li[1‐R‐2‐CO2‐1,2‐C2B10H10], R = CH3 (10), R = C6H5 (11), with Me3NBH2I gave 1,2‐CO2BH2NMe3‐1,2‐C2B10H10 (9a) or 1‐R‐2‐CO2BH2NMe3‐1,2‐C2B10H10, R = CH3 (10a), R = C6H5 (11a), as new boron analogs of esters. All of these compounds were characterized by IR spectroscopy, 1H, 13C and 11B NMR spectroscopy and chemical analyses. Copyright © 2003 John Wiley & Sons, Ltd.
Cobalt(II) and iron(II) bis(2,2′ : 6′,2″‐terpyridine) complexes functionalized with alkynes and cobalt carbonyl clusters
Authors: Constable Edwin C. , Hart Christopher P. , Housecroft Catherine E.
Published: May 2003

The preparation and characterization of new cobalt(II) and iron(II) complexes containing alkyne or cobalt cluster functionalized 2,2′ : 6′,2″‐terpyridine ligands are described. The cobalt(II) complexes exhibit paramagnetically shifted, but well‐resolved, 1H NMR spectra that are characteristic of low‐spin cobalt(II) solution species. Copyright © 2003 John Wiley & Sons, Ltd.
Bi‐ and tri‐metallic {Cp*RhCl} fragments partnered with carborane monoanions [CB11H6Y6]− (Y = H, Br): control of nuclearity by choice of anion
Authors: Patmore Nathan J. , Mahon Mary F. , Weller Andrew S.
Published: May 2003

Reaction of [Cp*RhCl2]2 (Cp* = pentamethylcyclopentadienyl) with Ag[closo‐CB11H12] affords the dinuclear salt [Cp*RhCl]2[CB11H12]2 (1), which in the solid state reveals a single carborane anion interacting with two {Cp*RhCl} fragments, via two BHRh interactions. With Ag[closo‐CB11H6Br6] the trimetallic complex [{Cp*Rh(µ2‐Cl)} 3(µ3‐Cl)][closo‐CB11H6Br6]2 (2) results. In the solid state, three metal fragments and four chloride ligands form seven‐corners of a cube, and the eighth vertex is completed by a cage CH unit hydrogen bonded to three bridging chloride ligands. Copyright © 2003 John Wiley & Sons, Ltd.
Synthesis of a novel boronated 1‐aminocyclobutanecarboxylic acid as a potential boron neutron capture therapy agent
Authors: Kabalka George W. , Yao Min‐Liang
Published: May 2003

A boronated aminocyclobutanecarboxylic acid was synthesized for potential use in neutron capture therapy. The synthesis involves the preparation of hydroxymethylcyclobutanone ketal, which is then converted to an amino acid using Bucherer–Strecker methodology. The molecule is modeled after the unnatural amino acid, 1‐aminocyclobutanecarboxylic acid, which has demonstrated high uptake in brain tumors. Copyright © 2003 John Wiley & Sons, Ltd.
Organometallic chemistry on rhodaheteroborane clusters: reactions with bidentate phosphines and organotransition metal reagents
Authors: Volkov Oleg , Macías Ramón , Rath Nigam P. , Barton Lawrence
Published: May 2003

This article reviews our recent work on the reactions of the rhodaheteroboranes [8,8‐(PPh3)2‐nido‐8,7‐RhSB9H10] (1) and [9,9‐(PPh3)2‐nido‐9,7,8‐RhC2B8H11] (2), and their derivatives, with the bidentate phosphines, dppe [(CH2)2(PPh2)2], dppp [(CH2)3(PPh2)2], and dppm [CH2(PPh2)2], and also with organotransition metal reagents. Simple substitution of the two PPh3 ligands by a single bidentate phosphine takes place when a 1 : 1 molar ratio of base (dppe or dppp) to rhodathiaborane (1) is used. However, in the presence of an excess of dppe or dppp, products containing 1 or 2 mol of base are formed. These products include a bidentate ligand on the metal and a monodentate ligand on the cage. The displaced hydrogen atom from the cage has moved to the metal center. These bis(ligand) species are unstable with respect to the loss of dihydrogen, affording closo‐11 vertex clusters with a pendent phosphine ligand on the cage. In concentrated solutions, the pendent phosphine attacks another cage to afford linked clusters. Under both sets of conditions, when dppm is used, only one product is observed. This species has two dppm ligands coordinated to the metal: one in a unidentate mode and the other bidentate. A similar product is obtained in the reaction of 2 with dppm, although the arrangement of the ligands on the metal in the product is different. Ligand exchange experiments on the dppm–thiaborane system lead to results that provide keys to the reaction pathways in some of these processes. The bis(dppm) derivatives of 1 and 2 are amenable to further derivatization. A second metal may be added, either as an exo‐polyhedral atom in a nido cluster in which the metal is part of a bidentate ligand, in the case of 1 and 2, or in a closo cluster derivative of 1 in which the metal is bonded to a dangling PPh2 moiety. Thus, it was possible to add the metals iridium, rhodium or ruthenium to the cluster, in the case of 1 and ruthenium in the case of 2. However, the reaction of more electrophilic organotransition metal reagents, such as Wilkinson's catalyst, with the dppm derivative of 1 affords species resulting from removal of ligand rather than incorporation of metal, and the products shed light on the rearrangement processes in these systems. Copyright © 2003 John Wiley & Sons, Ltd.
Syntheses and structures of mono‐cyclopentadienyl di‐iodide complexes of the lanthanides: X‐ray crystal structures of Cp‴LaI2py3 (Cp‴ = [η5‐C5H2(SiMe3)3‐1,2,4]−; py = pyridine) and Cp‴LaI2(bipy)py (bipy = 2, 2′‐bipyridine)
Authors: Giesbrecht Garth R. , Clark David L. , Gordon John C. , Scott Brian L.
Published: May 2003

[η5‐C5H2(SiMe3)3‐1,2,4]K reacts with LaI3(THF)4 in tetrahydrofuran (THF) to form the mono‐ring complex [η5‐C5H2(SiMe3)3‐1,2,4]LaI2(THF)x (1). Elemental analysis and 1H NMR spectroscopy indicate that the coordinated THF molecules are labile and are easily removed under vacuum. The THF adduct 1 is readily converted to the more stable pyridine complex [η5‐C5H2(SiMe3)3‐1,2,4]LaI2py3 (2) by the addition of excess pyridine to a toluene solution of 1. Although solid samples of 2 lose pyridine less readily, the pyridine molecules exchange with solvent molecules, and in the presence of a large excess of THF, 1 is re‐formed. Complex 2 may be crystallized from toluene, and an X‐ray diffraction study revealed a monomeric species with the two iodide ligands trans to each other, and three pyridines arranged in a meridional fashion. The addition of one equivalent of 2,2′‐bipyridine to a toluene solution of 1 yields the bipyridine adduct, [η5‐C5H2(SiMe3)3‐1,2,4]LaI2(bipy) (3). In contrast to 1 and 2, the bipyridine molecule in 3 remains ligated to the lanthanum center in all solvents. Complex 3·py may be crystallized from THF–pyridine; in this case, the presence of bipyridine forces a cis orientation of the two iodide ligands. Copyright © 2003 John Wiley & Sons, Ltd.
On the imposition of essential boundary conditions in natural neighbour Galerkin methods
Authors: Cueto E. , Cegoñino J. , Calvo B. , Doblaré M.
Published: May 2003

In this paper issues related to the imposition of essential boundary conditions in Natural Neighbour Galerkin methods are addressed. Both Sibson and non‐Sibson interpolants ability to exactly reproduce essential boundary conditions is investigated and a new analytical condition ensuring linear precision along explicitly described (i.e. CAD) boundaries in both two and three dimensions is presented. The paper is completed with some benchmark numerical examples. Copyright © 2003 John Wiley & Sons, Ltd.