bluuebunny/crossref_metadata_2025 huggingface dataset:
Further Investigation on Preparation, Structure and Electrochemical Properties of N-Alkyl- and N-Aryl-2-aza-[3]-ferrocenophanes
Authors: Sakano Tatsuaki , Horie Masaki , Osakada Kohtaro , Nakao Hidenobu
Published: December 2002

The reactions of 1,1′-bis(hydroxymethyl)ferrocene with primary amines such as 6-aminohexanol, cyclohexylamine, 4-phenylbutylamine, 2-isopropylaniline, 4-(trifluoromethyl)benzylamine, and 1-aminomethylferrocene in the presence of [RuCl2(PPh3)3] catalyst led to intermolecular condensation of the CH2OH and NH2 groups to afford N-alkyl- or N-aryl substituted 2-aza-[3]-(1,1′)-ferrocenophanes. Cyclic voltammograms of the obtained N-alkyl-2-aza-[3]-(1,1′)-ferrocenophanes exhibit reversible redox of the Fe center at E1/2 = −0.01 – +0.04 V (vs Ag+/Ag) and subsequent irreversible oxidation of the amino group of the ligand at Eox = 0.41–0.44 V. N-(4-Hydroxyphenyl)-2-aza-[3]-(1,1′)-ferrocenophane shows two pairs of reversible electrochemical oxidation and reduction at E1/2 = 0.04 and 0.44 V. The latter potential is significantly lower than the corresponding electrochemical oxidation of N-aryl-2-aza-[3]-(1,1′)-ferrocenophanes (0.68–0.75 V). The N-alkyl-2-aza-[3]-(1,1′)-ferrocenophanes react with MeI to cause methylation of the amino group to produce cationic 2-aza-[3]-(1,1′)-ferrocenophanes containing a quaternary nitrogen center. The iodo counter anion is easily replaced with BF4− or PF6−. Cyclic voltammograms of the cationic ferrocenophanes show the redox between ferrocene and ferrocenium at E1/2 = 0.37–0.42 V.
Syntheses, Crystal Structures and Magnetic Properties of Copper(I) Iodide Complexes with Nitronyl Nitroxide-Substituted Pyridine
Authors: Zhang Deqing , Ding Liang , Xu Wei , Yang Junling , Jin Xianglin , Zhu Daoben
Published: December 2002

Two new copper(I) iodide coordination compounds [Cu2I2(p-PYNN)4] (1) and [Cu4I4(m-PYNN)4] (2), where p-PYNN and m-PYNN are 4,4,5,5-tetramethyl-2-(4-pyridyl)-4,5-dihydro-1H-imidazol-1-oxy-3-oxide and 4,4,5,5-tetramethyl-2-(3-pyridyl)-4,5-dihydro-1H-imidazol-1-oxyl-3-oxide, respectively, were synthesized and characterized. They both were found to be fluorescent. Their crystal structures were determined: 1, triclinic, space group P1-, a = 13.668(3) Å, b = 14.280(3) Å, c = 7.273(1) Å, α = 90.18(3)°, β = 101.86(3)°, γ = 91.09(3)°, Z = 1, R = 0.0310 (Rw = 0.0805) for 4217 observed reflections with I ≥ 2σ(I); 2, triclinic, space group P1-, a = 15.569(9) Å, b = 16.247(7) Å, c = 15.103(9) Å, α = 94.48(5)°, β = 116.15(5)°, γ = 83.07(5)°, Z = 2, R = 0.0686 (Rw = 0.1933) for 8311 observed reflections with I ≥ 2σ(I). Magnetic studies indicated that 1 showed ferromagnetic behavior, while 2 displayed antiferromagnetic properties. Discussions about the relationship between their crystal structures and magnetic properties are also presented.
Photoreduction of a Self-Assembled (Lipidporphyrinato)iron(III) Complex in Saline by LMCT Excitation: Co-Aggregated Hyaluronic Acid Allows an Irreversible Electron Transfer
Authors: Yanagimoto Tetsuya , Nakagawa Akito , Komatsu Teruyuki , Tsuchida Eishun
Published: December 2002

An amphiphilic (tetraphenylporphyrinato)iron(III) derivative with four alkylphosphocholine groups and a proximal imidazole [(lipidporphyrinato)iron(III); 1a] was self-assembled in phosphate-buffered saline (pH 7.3, [NaCl] = 0.15 M) to form spherical micelles with a diameter of 10 nm. The obtained solution showed a distinct absorption band at 362 nm, which was assigned to the ligand-to-metal [Cl− to iron(III)] charge transfer (LMCT) transition. Light irradiation into this CT band under an Ar atmosphere did not induce any changes in the UV-vis absorption spectrum. On the other hand, the addition of glucose (150 mM) to the solution led to complete photoreduction of the central iron(III) ion, giving a five-N-coordinated high-spin iron(II) complex. It has also been found that a small excess amount of hyaluronic acid ([units] = 100 µM) showed the same effect. The photoreduction was only seen by LMCT irradiation in the presence of the saccharide. It probably occurred via intramolecular electron transfer from Cl− to iron(III), and the produced chlorine radical was scavenged by the saccharide, which prevented a back electron transfer reaction (the quantum yields; ca. 0.007). Interestingly, hyaluronic acid changed the morphology of the 1a assembly from the micelle to a thin fiber. This co-aggregated structure with hyaluronic acid would be responsible for the effective photoreduction of 1a. The viscosity of the fiber solution significantly decreased during the photoreduction, which suggests that radical trapping induces depolymerization of the hyaluronic acid. Laser flash photolysis experiments showed that the reduction and the imidazole association to the iron(II) center are completed within 50 ns after a laser pulse. The photoreduced (lipidporphyrinato)iron(II) fibers can reversibly bind and release O2 similar to the same fibers which were prepared by chemical reduction using ascorbic acid.
Control of the Association of Indolylfulgimide with Bis(acylamino)pyridine by Photochromism
Authors: Okuyama Tomoyuki , Yokoyama Yayoi , Yokoyama Yasushi
Published: December 2002

While the association constant of the colored form of a thermally irreversible photochromic indolylfulgimide with 2, 6-bis (octanoylamino)pyridine in toluene at 21 °C was 156 ± 11 mol−1 dm3 through triplex hydrogen bonding, that of its colorless form, generated by visible-light irradiation, was increased to 885 ± 63 mol−1 dm3. This result was supported by PM3 semiempirical molecular–orbital calculations that the difference of the association constants between the C-form and the E-form was mainly due to differences in the structures and conformations of the imide moiety.
Synthesis of [3H]-Labeled Bioactive Lipid A Analogs and Their Use for Detection of Lipid A-Binding Proteins on Murine Macrophages
Authors: Fukase Koichi , Kirikae Teruo , Kirikae Fumiko , Liu Wen-Chi , Oikawa Masato , Suda Yasuo , Kurosawa Motohiro , Fukase Yoshiyuki , Yoshizaki Hiroaki , Kusumoto Shoichi
Published: December 2002

Both endotoxic and antagonistic [3H]-labeled 2-(phosphonooxy)ethyl (PE) analogs of lipid A were synthesized with high purity and high specific radioactivity. Lipid A-binding proteins were detected by using the endotoxic analog of hexaacyl Escherichia  coli-type designated [3H] PE-506. The plasma membrane fractions from peritoneal macrophages derived from LPS-responder C3H/HeN mice and LPS-hyporesponder C3H/HeJ mice were separated by SDS-PAGE and transferred onto nitrocellulose membranes. The membranes were then incubated with the [3H] PE-506. Several [3H] PE-506 binding proteins were detected in both C3H/HeN and C3H/HeJ macrophages. Unlabeled hexaacyl lipid A inhibited the interaction between [3H] PE-506 and these proteins. The result suggests that there exist multiple binding sites for lipid A on macrophages. LPS-induced change in the profile of the cell surface lipid A binding proteins was observed in C3H/HeN macrophages, but not in C3H/HeJ macrophages, by preincubation of macrophages with LPS.
Synthesis of New Chiral Dopants Derived from 2-Phenylpropanoic Acid Derivatives for Nematic Liquid Crystals
Authors: Aoki Yoshio , Shitara Hiroaki , Hirose Takuji , Nohira Hiroyuki
Published: December 2002

New chiral dopants for nematic liquid crystals were synthesized using optically active 2-phenylpropanoic acid derivatives. The magnitude of the helical twisting power (HTP) was largely influenced by the terminal group of the asymmetric frame and the core structures. (S)-1-[4-(trans-4-Butylcyclohexyl)phenyl]-2-phenylpropane-1-one showed a large HTP value (20.4 µm−1). The relationship between the HTP and the molecular structures of the chiral dopants is discussed.
Metallaphosphorane Chemistry: Preparations, Structures, and Reactivities
Authors: Nakazawa Hiroshi , Kubo Kazuyuki , Miyoshi Katsuhiko
Published: December 2002

Transition-metal phosphorane complexes, [Cp(CO)2M{P(OC6H4Y)2}] (M = Fe, Ru; Y = NH, NMe, O) have been prepared from [Cp(CO)2M{P(OPh)3}]PF6, o-HOC6H4YH, and a Lewis base. With the use of Et4NF in place of o-HOC6H4YH, [Cp(CO)2Fe(PF4)] and [Cp(CO)2Fe{P(OPh)F3}] have been prepared. These reactions involve nucleophilic attacks of an organic or an inorganic nucleophile at a trivalent phosphorus coordinated to a transition metal and substitution on the phosphorus. The reaction of phosphorane HP(OC6H4NH)2 with a Lewis base leads to NH proton abstraction to give the amide HP(OC6H4NH)(OC6H4N−) Subsequent treatment of the anion with EX (MeI, [Cp(CO)2FeCl]) has yielded P-substituted phosphorane EP(OC6H4NH)2 whereas that with E′X (SiMe3Cl, GeMe3Cl, SnMe3Cl, [Cp(CO)CoI2]) has yielded N-substituted phosphorane HP(OC6H4NH)(OC6H4NE′) X-ray structure analyses and spectroscopic data for these metallaphosphoranes reveal that the transition metal fragment serves as a strong π donor toward a phosphorane fragment. The activation parameters for Berry pseudorotation around the phosphorus in several metallaphosphoranes have been determined. The reactivity of metallaphosphoranes was also examined. The iron and ruthenium phosphoranes react with a Lewis base to give Li[{η5-C5H4P(OC6H4Y)2}(CO)2M] In this reaction, one of the protons on the Cp ring is abstracted by the Lewis base and then migration of the phosphorane fragment to the Cp ring takes place. This constitutes the first reported migration of a hypervalent element fragment.
Aromatic Character of Large Deltahedral Borane Dianions As Estimated Using the Kettle–Tomlinson Bonding Model
Authors: Aihara Jun-ichi
Published: December 2002

Lipscomb et al. designed the low-energy deltahedral isomers of borane dianions BnHn2− for n ranging from 13 to 24. We evaluated the topological resonance energies (TREs) of these dianions by applying the Kettle–Tomlinson (KT) bonding model to them. It was then found that except for B18H182− (D6d) the TRE per BH unit is highly correlative with the PRDDO binding energy per BH unit. This indicates that the thermodynamic stability of deltahedral borane dianions is determined primarily by aromaticity. B18H182− (D6d) has a very small TRE per BH unit, strongly reflecting its small HOMO–LUMO energy separation. Thus, the KT model is useful for describing electronic characteristics of large deltahedral borane dianions.
Preparation, Crystal Structures and Spectroscopic Properties of a Series of Cobalt(III) Phosphine Complexes: trans- and cis-[Co(dtc)2(PMe3−nPhn)2]+ (dtc = N,N-Dimethyldithiocarbamate; n = 0, 1, 2 or 3)
Authors: Suzuki Takayoshi , Kashiwamura Shinsaku , Kashiwabara Kazuo
Published: December 2002

A series of new cobalt(III) phosphine complexes of trans-[Co(dtc)2(PMe3−nPhn)2]BF4 (dtc = N,N-dimethyldithiocarbamate; n = 0, 1, 2 or 3) and cis-[Co(dtc)2(PMe3 or PMe2Ph)2](BF4 or PF6) have been prepared and their crystal structures and spectroscopic properties have been investigated. It is found that the Co–S bond lengths vary with steric and electronic factors of the P-ligands; i.e. (1) the intramolecular π–π stacking interaction between the dtc plane and the phenyl ring of the P-ligand, and (2) the electronic trans influence of the trans-positioned P-ligand. The strength of electronic trans influence decreases as PMe3 > PMe2Ph > P(OCH2)3CEt in accordance with the order of σ-donicity strengths. In the series of trans-isomers, the electronic trans influence is competitive with the steric requirement of the phosphine to elongate the mutually trans Co–P bonds. The steric trans influence via the equatorial dtc ligands for such an elongation of the Co–P bonds seems to be negligible, which is in sharp contrast to the situation for via pentane-2,4-dionate (acac) ligands in the analogous complexes, trans-[Co(acac)2(PMe3−nPhn)2]PF6. This is probably due to the compactness of dtc and the resulting open space at the Co atom. The fact that the Co–P bond lengths in the dtc complexes are shorter than those in the acac complexes is reflected in the larger stability toward hydrolysis of the dtc complexes. In the UV-vis absorption spectra, the degenerate splitting component (a1Eg) of the first d–d transition band of trans-[Co(dtc)2(PMe3−nPhn)2]+ is observed at almost the same position (within 300 cm−1) as that of the corresponding acac complexes, while the transition energies of the P-to-Co LMCT of these two series of complexes are rather different (at least 2700 cm−1) from each other. Furthermore, the first and the second d–d transition bands of cis-[Co(dtc)2(PMe3 or PMe2Ph)2]+ are observed at lower energy than those of cis-[Co(dtc)2{P(OMe)3}2]+ in spite of a weaker σ-donor of phosphite. The separation of the first and the second d–d transition bands of the P(OMe)3 complex is remarkably smaller than the separation of the bands of the PMe3 one, being indicative of a further reduction of the interelectronic repulsion in the P(OMe)3 complex.
N,N-Dimethylindoaniline Mediated-Amperometric Detection of l-lactate
Authors: Hirano Keisuke , Yamato Hitoshi , Kunimoto Kazuhiko , Ohwa Masaki
Published: December 2002

It was found that N,N-dimethylindoaniline works as an excellent electron-transfer mediator for lactate oxidase. The second-order rate constant (kmed) with lactate oxidase in solution was much higher than that of other typical mediators, such as ferrocene and potassium hexacyanoferrate(II). An enzyme electrode using this compound as a mediator showed a larger response current and a higher sensitivity to lactate than a Pt-based H2O2 detecting lactate sensor. This sensor demonstrated a clear independence on the oxygen concentration in a buffer and a quite low interference current by ascorbic acid, etc. A H2O2 detecting sensor was strongly interfered by acetaminophen and uric acid, while a mediator based sensor was slightly influenced by uric acid. This sensor also showed good durability, which retained more than 90% of the initial activity until day 11.
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

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

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

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

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

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

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

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 > 2 > 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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

For lithium-ion batteries of C/(spinel Li–Mn–O), the sever capacity loss occurs after storage of the battery at >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

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

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

The 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.
Thermal Stability of Hydroxyapatite Whiskers Prepared by Homogenous Precipitation
Authors: Zhang H. , Yan Y. , Wang Y. , Li S.
Published: December 2002

Hydroxyapatite (HA) whiskers prepared by homogenous precipitation method were heat treated in air. The phase composition of HA whiskers and their microstructure were investigated before and after the heat treatment using XRD, FT‐IR, SEM, and TG‐DSC techniques. It was revealed that the HA whiskers obtained were morphologically stable at elevated temperatures below 1200°C. A phase transition of the HA whiskers took place obviously at about 1200°C. The thermal stability of HA whiskers was related to the chemical composition and crystallinity. They could be used as reinforcement materials in dense HA ceramics and porous HA ceramics.
Orientation Averaging for Stiffness and Thermal Expansion of Short Fiber Composites
Authors: Gusev A. , Heggli M. , Lusti H.R. , Hine P.J.
Published: December 2002

It is fairly common in practice that during injection moulding, the mold filling process results in non‐uniform fiber orientation distributions in the final injection molded short fiber reinforced composite part. It would be very attractive to employ an orientation averaging scheme to form predictions for the design of short fiber reinforced composite parts. Here, the authors use a finite‐element‐based numerical procedure developed by themselves and, for the first time, directly predict the stiffness and thermal expansion of several hundred multi‐fiber computer models with a variety of different predefined fiber orientation states.
Actin‐bindende marine Makrolide: Totalsynthese und biologische Bedeutung
Authors: Yeung Kap‐Sun , Paterson Ian
Published: December 2002

Marine 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

Controlled 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

Using 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
Thermoplastic polymers as modifiers for urea‐formaldehyde (UF) wood adhesives. II. Procedures for the preparation and characterization of thermoplastic‐modified UF wood composites
Authors: Rachtanapun P. , Heiden P.
Published: December 2002

Wood composites were prepared by using wood flour (sugar maple, Acer saccharum March) and thermoplastic‐modified urea‐formaldehyde (UF) suspensions. Thermoplastic (5–10% w/v) was introduced into the UF suspension as an aqueous solution, a self‐stabilized dispersion in water, or as a surfactant‐stabilized latex. The modified suspension was blended with wood flour, and the blend was cured by using a cure cycle that was suitable for all the thermoplastic‐modified UF formulations and unmodified UF controls. The wood flour composites were tested by using a notched Izod impact strength test. All formulations containing surfactant decreased the impact strength by ∼ 30–40% relative to the unmodified UF control, whereas the water‐soluble thermoplastic had no effect on the impact strength. The formulations with self‐dispersed thermoplastics all increased the notched Izod impact strength, with the greatest increase being 69% more than the UF control, except in a single instance when the molecular weight of the thermoplastic was very high, which decreased resin flow. Increasing the thermoplastic content from 5 to 10% w/v did not further improve the impact test results. Scanning electron microscopy of the fracture surfaces showed morphological differences in the systems that varied with the thermoplastic and method of thermoplastic addition to the UF suspension.© 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 898–907, 2003
Study on preparation of heterogeneous polysulfone affinity filter membrane and its sorption properties for Hg2+
Authors: Wang Bing , Cui Yongfang , Du Qiyun , Pei Guangling
Published: December 2002

High quality heterogeneous polysulfone affinity flat filter membranes having chelating groups were prepared by phase separation by the use of blends of chelating resin and polysulfone as membrane materials, N,N‐dimethylacetamide as the solvent, and water as the extraction solvent. The effects of blending ratio, chelating resin grain size, and temperature of casting solution on the structure of affinity membranes were investigated. The sorption process of an affinity filter membrane for Hg2+, adsorbed under various chelating conditions such as chelating resin grain size, pH value, and the concentration of the metallic ion solution, was also studied. The results revealed that the greatest chelating capacity of an affinity filter membrane for Hg2+ was 1050 μg/cm2 per membrane under appropriate conditions, and the sorption isotherms of Hg2+could be expressed by the Freundlich sorption model. Dynamic chelating experiments indicated that the Hg2+ could be extracted with the affinity filter membrane and reextracted under acidic conditions. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 908–915, 2003
Surface modification of jute yarn by photografting of low‐glass transition temperature monomers
Authors: Sawpan Moyeenuddin A. , Khan Mubarak A. , Abedin M. Z.
Published: December 2002

Jute yarns were grafted with three types of vinyl monomers of different functionalities such as methyl acrylate (MA), ethyl acrylate (EA), and 2‐hydroxyethyl acrylate (HEA) with ultraviolet radiation. The graft copolymerization reaction between the cellulose of the jute fibers and the monomer and the chemical environment of the treated fibers were confirmed by Fourier transform infrared spectroscopy. The reduction of OH groups and increment of >CO groups in treated jute yarns were observed. DSC studies showed that the treated jute fibers were more thermally stable compared to the untreated one. The surface topography of the yarns was analyzed by an environmental scanning electron microscope. Different parameters, such as concentration of monomers and irradiation time, were optimized with the extent of mechanical properties such as tensile strength and elongation at break of the jute yarn. MA, EA, and HEA produced enhanced tensile strengths of 87, 78, and 85%, respectively. The monomers MA, EA, and HEA showed improved elongations at break of 118, 91, and 76%, respectively. The water uptake of treated and untreated jute yarns were studied. The maximum water uptake was observed of the grafted sample compared to the untreated jute yarn. The effects of additives such as urea on mechanical properties were also studied. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 993–1000, 2003
Rice husk ash filled natural rubber. I. Overall rate constant determination for the vulcanization process from rheometric data
Authors: da Costa H. M. , Visconte L. L. Y. , Nunes R. C. R. , Furtado C. R. G.
Published: December 2002

Black rice husk ash (BRHA) and white rice husk ash (WRHA) were incorporated into natural rubber (NR) using a laboratory‐size two‐roll mill. A conventional vulcanization system (CV) was chosen and cure studies were carried out on a TI‐100 Curometer. The torque curves were obtained at 150, 160, 170, and 180°C. The overall rate and the apparent activation energy for the vulcanization process were calculated for each compound assuming that vulcanization follows first‐order kinetics. For comparison purposes, two commercial fillers, precipitated silica (Zeosil‐175) and carbon black (N762), were also used. It was observed that addition of WRHA to NR compounds increased the cross‐linking rate and lowered the apparent activation energy more markedly than the other fillers. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 1194–1203, 2003
Filled elastomers: Mid‐ and near‐IR spectroscopic determination of rubber dimensions in composite in unstretched state and under uniaxial extension
Authors: Bokobza Liliane , Rapoport Olivier
Published: December 2002

A Fourier transform IR investigation of reinforced elastomers is presented. The work is essentially carried out in the near‐IR range, that allows the analysis of thick samples. The dependence of the average rubber phase dimensions on the filler loading is analyzed. The matrix chain deformation processes can be evaluated by looking at the strain dependence of the intensity of specific absorption bands of the polymer. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 1204–1208, 2003
Preparation of magnetic poly(vinyl alcohol) (PVA) materials by in situ synthesis of magnetite in a PVA matrix
Authors: Lin Hai , Watanabe Yoshimi , Kimura Mutsumi , Hanabusa Kenji , Shirai Hirofusa
Published: December 2002

An easy method for manufacturing homogeneous inorganic–organic materials, especially composite fibers, was obtained by the in situ synthesis of inorganic particles within polymer matrices. In this article, nanosized magnetite particles were synthesized in situ within poly(vinyl alcohol) (PVA) solutions by precipitating Fe2+ ions or a mixture of Fe2+ and Fe3+ ions with NaOH solution. As a result, magnetite particles with an average diameter of 20 nm were obtained homogeneously within the solutions because of the tridimensional structure and chelating capacities of PVA. Transparent films were obtained by a casting method, and six kinds of magnetic PVA fibers were also prepared by a wet‐spinning method from the solutions containing magnetite nanoparticles. The mechanical properties and the saturation magnetization of the fibers were measured. These fibers, which contain iron ions with a maximum content of 17.63 wt %, can be successfully fabricated by the in situ synthesis and they exhibit excellent magnetization properties (i.e., the largest saturation magnetization is 13.38 emu/g). © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 1239–1247, 2003
Synthesis and characterization of self‐doped poly(aniline‐co‐aminonaphthalene sulfonic acid) nanotubes
Authors: Wei Zhixiang , Wan Meixiang
Published: December 2002

Self‐doped poly(aniline‐co‐aminonaphthalene sulfonic acid) (PANI‐ANSA) was synthesized by the copolymerization of 5‐aminonaphthalene‐2‐sulfonic acid (ANSA) and aniline. Scanning electron microscopy and transmission electron microscopy showed that the morphology of PANI‐ANSA synthesized at a high molar ratio of aniline to ANSA was nanotubular, but at a low molar ratio, only a granular morphology formed. A possible formation mechanism for nanotubes was proposed. PANI‐ANSA had better thermal stability than HCl‐doped polyaniline; the highest onset decomposition temperature was as high as 340°C because of SO3H linked with the polymer backbone by a covalent bond. PANI‐ANSA was partially soluble in basic solutions, and its conductivity was between 10−2 and 10−4 S/cm, depending on the sulfonation degree. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 1297–1301, 2003