bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hydrogen-Bond-Like Nature of the CH/π Interaction as Evidenced by Crystallographic Database Analyses and Ab Initio Molecular Orbital Calculations
Authors: Takahashi Osamu , Kohno Yuji , Iwasaki Sachiyo , Saito Ko , Iwaoka Michio , Tomoda Shuji , Umezawa Yoji , Tsuboyama Sei , Nishio Motohiro 
Published: December 2002

Abstract
Spatial distribution of CH hydrogen atoms with reference to a six-membered carbon aromatic ring was analyzed in the crystal structures deposited in the Cambridge Structural Database (CSD). The crystal data showed the propensity that the CH hydrogen atoms lie above the center of the aromatic ring to form interatomic CH/π contacts. Investigation of the effects of the CH proton acidity on the strength and the structure of the CH/π interaction has demonstrated that the distance between the hydrogen atom and the π plane (Dpln) decreases with increase of the CH proton acidity (Dpln: CCH3 ≅ sp2-CH &gt; sp-CH ≅ Cl2CH2 &gt; Cl3CH), and that the C–H···π access angle (α) tends to approach 180° in the same order. Further, a negative correlation has been found between Dpln and α. The directional preferences are in accord with the property of conventional hydrogen bond, indicating a hydrogen-bond-like character of the CH/π interaction. In order to elucidate the intrinsic nature of the CH/π interaction, ab initio calculations [MP2/6-311++G(d,p)] were carried out for methane/benzene, ethylene/benzene, and acetylene/benzene complexes. Potential surfaces obtained for the three model supramolecules are consistent with the results from the CSD analyses.
Site-Selective Deposition of Enzyme/Polyelectrolyte Multilayer Films on ITO Electrodes Controlled Electric Fields
Authors: Shi Lixin , Sun Junqi , Liu Junqiu , Shen Jiacong , Gao Mingyuan 
Published: December 2002

Abstract
Electric field directed layer-by-layer assembly (EFDLA) approach was for the first time employed to realize site-selective deposition of enzyme/polyelectrolyte films on two independent indium-tin-oxide electrodes. Enzyme activities and thickness of the resulted films were investigated and compared with those of normal layer-by-layer self-assembled films of enzyme. All results prove that the site-selective deposition was successfully realized at applied voltage of 1.2 V.
A Simple In Situ Hydrogen Bond Interaction to Homogeneous Dispersion of Gold Nanoparticles in SiO2 Matrix Using Dendrimer as Template
Authors: Zhou Yong , Ma Chenghuan , Itoh Hideaki , Naka Kensuke , Chujo Yoshiki 
Published: December 2002

Abstract
A novel dendrimer-templated gold nanoparticle was homogeneously dispersed in SiO2 matrix via in situ hydrogen bond interaction between the dendrimer and silica matrix.
Fabrication of Three-component Micropatterned Organosilane Monolayer by a Stepwise Photolithography Process
Authors: Koga Tomoyuki , Otsuka Hideyuki , Takahara Atsushi 
Published: December 2002

Abstract
Three-component micropatterned organosilane monolayer was successfully fabricated on Si-wafer substrate by a stepwise photolithography process. Scanning force microscopic observations revealed that three kinds of organosilane monolayers with different physicochemical properties were area-selectively immobilized on a Si wafer.
UV Light Driven Morphological Changes in Lamella Films of a Poly(ethylene imine) Complex with 4-Dodecyloxycinnamic Acid
Authors: Ohtani Osamu , Takagi Katsuhiko 
Published: December 2002

Abstract
A cast multilayer film of poly (ethylene imine) (PEI) complex involving 4-dodecyloxycinnamic acid (C12OCin) was found to show layer shrinkage along the c-axis on the glass plate under UV illumination at λ&gt;300 nm. The bilayer units in the stacked lamella film successively shifted from 4.7 to 4.2 nm in length, induced by the E-to-Z photoisomerization, indicating continuous changes in the layer distances. This shrinkage behavior shows a contrast to that observed in the case of an ion-pair film of dioctadecyldimethylammonium cinnamate (DDAC) which exhibits no intermediate layer distance during a similar photoinduced shrinkage of the film.
The Synthesis of Two Types of Layered Niobate Hybrid Materials by the Selective Intercalation of Ionic Porphyrin
Authors: Tong Zhiwei , Shichi Tetsuya , Kasuga Yoshiyuki , Takagi Katsuhiko 
Published: December 2002

Abstract
K4Nb6O17 is a layered semiconductor possessing two different layer structures, i.e., interlayers I and II. The present paper reports on the selective synthesis of two types of layered niobate hybrid materials by the introduction of 5,10,15,20-tetrakis(1-methyl-4-pyridinium)-21H,23H-porphyrin (TMPyP4+) into either interlayer I or into both I and II by a guest-guest exchange method using the intercalation compounds (MV2+)xK4−2xNb6O17 and (PrNH3+)xH4−xNb6O17 as precursors.
Separation of Americium(III) from Lanthanide by Encapsulating Hexadentate-ligand
Authors: Watanabe Masayuki , Mirvaliev Rinat , Tachimori Shoichi , Takeshita Kenji , Nakano Yoshio , Morikawa Koshi , Mori Ryohei 
Published: December 2002

Abstract
Am(III) is encapsulated in an aqueous phase by a podand-type ligand, N,N,N′,N′-tetrakis(2-methylpyridyl)ethylenediamine (TPEN), and is extracted selectively over trivalent lanthanide in an organic phase using nitrobenzene. The extraction of Am(III) using TPEN shows higher selectivity and chemical stability than other conventional ones using nitrogen-donor ligands.
Fast Preparation of Nano-sized Nickel Particles under Microwave Irradiation without Using Catalyst for Nucleation
Authors: Tsuji Masaharu , Hashimoto Masayuki , Tsuji Takeshi 
Published: December 2002

Abstract
Nano-sized nickel particles have been prepared through reduction of Ni(OH)2 with ethylene glycol under microwave irradiation. Without using such a catalyst as Pt for nucleation, spherical nickel particles with a diameter of 6±3 nm were produced within 5 min.
[{(H2O)Ni(enMe)2MoV4MoVI4VIV8(VVO4)O40}2{Ni(enMe)2}][Ni(enMe)2]4·8H2O: The First Dimer of Polyoxometalates Linked through Coordination Fragment
Authors: Cui Xiao-Bing , Yang Guo-Yu 
Published: December 2002

Abstract
The hydrothermal reaction of V2O5, MoO3, NiCl2·6H2O, enMe (1,2-diaminopropane) and H2O produces [{(H2O)Ni(enMe)2MoV4MoVI4VIV8(VVO4)O40}2{Ni(enMe)2}][Ni(enMe)2]4·8H2O, which is the first compound containing polyanion dimer linked by transition metal coordination fragment. The structure of this compound was determined by single crystal X-ray diffraction, EPR and IR analysis.
All Solid-state Lithium Secondary Batteries Using High Lithium Ion Conducting Li2S–P2S5 Glass-Ceramics
Authors: Mizuno Fuminori , Hama Shigenori , Hayashi Akitoshi , Tadanaga Kiyoharu , Minami Tsutomu , Tatsumisago Masahiro 
Published: December 2002

Abstract
All solid-state cells of In/LiCoO2 using the 80Li2S·20P2S5 (mol%) glass-ceramics with high ambient temperature conductivity of about 10−3 S cm−1 as a solid electrolyte were fabricated, and the cell performance was investigated. Although an irreversible capacity was observed at the 1st cycle, the solid-state cell exhibited excellent cycling performances with the reversible charge-discharge capacities of about 100 mAh g−1 even after 200 cycles.
Stereocontrolled Syntheses of Carotenoid Oxidative Metabolites, (−)-Loliolide, (−)-Xanthoxin, and Their Stereoisomers
Authors: Kuba Masako , Furuichi Noriyuki , Katsumura Shigeo 
Published: December 2002

Abstract
We achieved the stereocontrolled syntheses of (−)-loliolide, (−)-xanthoxin, and their stereoisomers from (+)- or (−)-3-alkoxy-6-hydroxymethyl-1,1,5-trimethylcyclohexene through the corresponding syn and anti-epoxides, respectively, which were obtained by utilizing the highly diastereoselective Sharpless asymmetric epoxidation or mCPBA oxidation.
Efficient Nonsintering Type Dye-sensitized Photocells Based on Electrophoretically Deposited TiO2 Layers
Authors: Miyasaka Tsutomu , Kijitori Yujiro , Murakami Takurou N , Kimura Mitsuhiro , Uegusa Sadao 
Published: December 2002

Abstract
A non-sintering method for preparing nanoporous semiconductor layers for dye-sensitized photocells was developed in which TiO2 particles were electrophoretically deposited on an electrode and post-treated by chemical vapor deposition of Ti alkoxide and microwave irradiation. The method provides photocells with energy conversion efficiency up to 4.1% under irradiation of AM1.5 light (100 mW/cm2).
Stereoselectivity in Intramolecular Cyclization of Non-conjugated Unsaturated Ketones by Electroreduction
Authors: Nishiguchi Ikuzo , Goda Satoshi , Yamada Kouji , Yamamoto Yoshimasa , Maekawa Hirofumi 
Published: December 2002

Abstract
This study showed some decrease in stereoselectivity in electroreductive intramolecular cyclization of nitrogen-containing non-conjugated enones in comparison with high stereoselectivity for the corresponding enones possessing an all-carbon-chain or a sulfur-containing chain. This phenomenon may provide some actual experimental supports for the remarkable stereochemical features of the electroreductive cyclization.
Titelbild: Angew. Chem. 24/2002
Authors: Marlin Dana S. , Bill Eckhard , Weyhermüller Thomas , Rentschler Eva , Wieghardt Karl 
Published: December 2002

AbstractDas Titelbild zeigt die Struktur eines paramagnetischen Dimangankomplexes, der an ein entferntes organisches Radikal gebunden ist. Die weit reichenden magnetischen Wechselwirkungen zwischen den beiden Zentren mit S=1/2 in diesem Komplex können als Modell einer ähnlichen Situation, die im S2Yz.‐Zustand des Photosystems II (PSII) vorliegt, betrachtet werden. In ihrer Zuschrift auf Seite 4969 ff. erhellen D. S. Marlin, E. Bill und K. Wieghardt et al. die Natur dieser Wechselwirkung durch Verwendung von SQUID‐Messungen und Zweikanal‐X‐Band‐EPR‐Spektroskopie. Eine der bemerkenswertesten Beobachtungen in solchen Zweikanal‐EPR‐Messungen ist die Identifizierung von gut aufgelösten „verbotenen“ Halbfeld‐Multilinien‐Signalen bei g=4, die von dipolaren Kopplungen herrühren. Letzteres könnte im Zusammenhang mit einem wenig verstandenen Signal bei g=4.1, das in verschiedenen EPR‐Spektren des PSII auftritt, von Bedeutung sein.
Curing and thermal behavior of epoxy resin in the presence of silicon‐containing amide amines
Authors: Khurana Parveen , Aggarwal S , Narula A. K. , Choudhary Veena 
Published: December 2002

AbstractThe article describes the synthesis and characterization of silicon‐containing amide amines obtained by the reaction of bis(4‐chlorobenzoyl)dimethylsilane with 4,4′‐diaminodiphenyl ether, 4,4′‐diaminodiphenyl methane, 4,4′‐diaminodiphenyl sulfone/3,3′‐diaminodiphenyl sulfone, bis(3‐aminophenyl)methyl phosphine oxide, and tris(3‐aminophenyl)phosphine oxide with dimethyl acetamide as a solvent. Structural characterization of amide amines was done with Fourier transform infrared and 1H‐NMR spectroscopy. We used these aromatic amide amines as curing agents to investigate the effect of structure and molecular size on the curing and thermal behavior of diglycidyl ether of bisphenol A (DGEBA). The curing behavior of DGEBA in the presence of stoichiometric amounts of silicon‐containing aromatic amide amines was investigated by differential canning calorimetry. A broad exothermic transition in the temperature range of 200–300°C was observed in all the samples. The peak exotherm temperature was lowest in the case of phosphorus‐containing amides and was highest in the case of ether‐containing amides. Thermal stability of the isothermally cured resins was evaluated with dynamic thermogravimetry in a nitrogen atmosphere. A significant improvement in the char yield was observed with silicon‐containing amines, and it was highest in case of samples with both silicon and phosphorus as flame‐retarding elements. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 1345–1353, 2003
Natural weathering of polypropylene in a tropical zone
Authors: Bedia Elinor L. , Paglicawan Marissa A. , Bernas Cynthia V. , Bernardo Severino T. , Tosaka Masatoshi , Kohjiya Shinzo 
Published: December 2002

AbstractNatural weathering of isotactic polypropylene (PP) plates (2 mm in thickness) was conducted for 15 months in the Philippines. Optical microscopy, scanning electron microscopy, and atomic force microscopy revealed that the surface layer (200–300 nm in thickness) was affected in the first month, and cracks are formed toward the deeper layer. On the basis of the microscopic observations along with FTIR, DSC, GPC, and tensile strength measurements, the following degradation mechanism of PP was proposed. At first, through oxygen introduced into the PP, only the surface layer seems to be affected. Gradually, the surface layer may be removed, exposing the inner layer. Then, molecular chains of the inner layer start to be degraded, accompanying a significant loss of tensile properties. Part of the degraded materials seems to be eroded, leading to the formation of cracks on the surface of the uncovered inner layer. Finally, the original surface layer may be totally eroded, making the structure of the inner layer (which should reflect the spherulitic texture) evident. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 931–938, 2003
Conducting properties of iodine‐doped low‐density polyethylene–poly(4‐vinylpyridine) blends
Authors: da Silva Sidnei Luis Andrade , Temperini Marcia Laudelina Arruda , Gomes De Barros Glaucione 
Published: December 2002

AbstractThe conductivities of blends of low‐density polyethylene and poly(4‐vinyl pyridine) (P4VP) were studied. The blends were synthesized by in situ sorption and thermal polymerization of 4‐vinylpyridine in low‐density polyethylene. They showed, after iodine doping, conductivities of 1.7 to 5.0 × 10−7 S cm−1 at 298 K, depending on the P4VP mass increment into the matrix. Their conductivities were one order of magnitude higher for measurements at 338 K. The optimum ratio of iodine to pyridine (n) which gave the highest conductivity was 0.21. The thermal stability of doped blends was acceptable for their uses as electrochemical devices. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 939–944, 2003
Synthesis and properties of polyimides containing bisphenol unit and flexible ether linkages
Authors: Leu Tsu‐Shang , Wang Chun‐Shan 
Published: December 2002

AbstractA series of novel polyimides was prepared from various diamines (with bisphenol units) and various aromatic tetracarboxylic dianhydrides via a two‐step (thermal imidization) method. The monomers and polymers were produced in high yields. The benzophenone series exhibited better solubility than the pyromellitic series and, especially, those with the alkyl (methyl)‐substituted ring exhibited good solubility and could be readily dissolved in polar aprotic solvents such as dimethylformamide and N,N′dimethylacetamide. The glass transition temperatures of all polyimides were found to be 235–322 and 223–332°C, respectively, by DSC and dynamic mechanical analysis. Thermogravimetric analyses indicated that the polymers were fairly stable up to 482–617°C (10 wt % loss in N2) and 480–610°C (10 wt % loss in air). Wide‐angle X‐ray diffractograms revealed that most polyimides were predominantly amorphous. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 945–952, 2003
Polymer blends of poly(ethylene‐2,6‐naphthalate) with polystyrene compatibilized by styrene‐glycidyl methacrylate copolymers. I. Rheology, morphology, and mechanical properties
Authors: Huang Jieh‐Ming , Ju Ming‐Yih , Hung Chen‐Jui , Luoh Wen‐Chin , Chang Feng‐Chih 
Published: December 2002

AbstractThe compatibilization of blends of poly(ethylene‐2,6‐naphthalate) (PEN) with polystyrene (PS), through the styrene‐glycidyl methacrylate copolymers (SG) containing various glycidyl methacrylate (GMA) contents, was investigated in this study. SG copolymers are able to react with PEN terminal groups during melt blending, resulting in the formation of desirable SG‐g‐PEN copolymers in the blend. These in situ formed copolymers tend to reside along the interface preferentially as the result of interfacial reaction and thus function as effective compatibilizers in PEN/PS blends. The compatibilized blends exhibit higher viscosity, finer phase domain, and improved mechanical properties. It is found that the degree of grafting of the in situ formed SG‐g‐PEN copolymer has to be considered as well. In blends compatibilized with the SG copolymer containing higher GMA content, heavily grafted copolymers would be produced. The length of the styrene segment in these heavily grafted copolymers would be too short to penetrate deep enough into the PS phase to form effective entanglements, resulting in the lower compatibilization efficiency in PEN/PS blends. Consequently, the in situ formation of SG‐g‐PEN copolymers with an optimal degree of grafting is the key to achieving the best performance for the eventually produced PEN/PS blends through SG copolymers. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 967–975, 2003
Miscibility and crystallization of metallocene polyethylene blends with polypropylene
Authors: Li Jun , Shanks Robert A. , Long Yu 
Published: December 2002

AbstractThe crystallization and morphology of very‐low‐density polyethylene (VLDPE) and ultra‐low‐density polyethylene (ULDPE) blends with isotactic polypropylene (PP) were studied by differential scanning calorimetry (DSC) and hot‐stage optical microscopy (HSOM) with polarized light. In particular, the isothermal crystallization of PP in molten PE was investigated. A polypropylene homopolymer was melt‐blended with six types of VLDPEs and ULDPEs, with variations in branch content and length and in molecular weight. All the blends contained 20% PP by mass. It was found that the crystallization temperatures of PP and PE changed in the blends, and the crystallization of PP was affected by branch length and content and by the molecular weight of the PE, indicating a certain degree of miscibility between PP and PE. The isothermal crystallization rate of PP decreased in the blends; in particular, the crystallization rate of PP was slower in the ULDPE with lower MFI, suggesting that crystallization of PP was hindered by PE and that its rate was regulated by the viscosity of ULDPE. HSOM images showed that a portion of the PP crystallized from molten PE, although phase separation was obvious, providing additional information on the miscible behavior between PP and VLDPEs (or ULDPEs). Furthermore, the miscible level between the PP and the ULDPEs was higher than that between the PP and the VLDPEs because the degree of change in the crystallization behavior of the PP and PE was greater in the PP–ULDPE blends. This was possibly a result of the higher branch content in the ULDPE. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 1179–1189, 2003
Oxygen enrichment across blend membranes of bipyridine and ethyl cellulose
Authors: Huang Mei‐Rong , Xu Qian‐Wei , Gu Shu‐Ying , Wu Yan‐Hui , Dong Zhi‐Qing , Wang Jian , Shao Hong‐Tao , Wang Xue‐Song 
Published: December 2002

AbstractBlend membranes of 2,2′‐bipyridine (2BP) or 4,4′‐bipyridine (4BP) with ethyl cellulose (EC) containing no more than 25 wt % BP are prepared and evaluated for their oxygen enrichment by both the constant pressure–variable volume method and the constant volume–variable pressure method. The actual air‐separation ability through the 2BP/EC blend membrane containing 1.5–7 wt % 2BP are enhanced while the permeated flux is slightly increased in comparison with the virgin EC membrane. Among the 2BP/EC blend membranes examined, the 2BP/EC blend membrane containing 3 wt % 2BP offers the best oxygen/nitrogen permselectivity and yields the highest oxygen concentration of 42.7% at the transmembrane pressure difference of 0.75 MPa and 25°C. Like other homogeneous dense membranes, the BP/EC blend membrane demonstrates strong dependencies on the transmembrane pressure difference, retentate/permeate flux ratio, and operating temperature. It possesses higher activation energy of oxygen and nitrogen permeation than those of the virgin EC membrane in the tested temperature range of 9.7–60°C. The CO2 over CH4 permselectivity through EC membranes can be improved by introducing 4BP, and the ideal oxygen over nitrogen separation factor through the 4BP/EC (10/90) membrane increases 16% at the upstream pressure of 10 bar compared with the virgin EC membrane. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 1371–1381, 2003
Novel degradable polyphosphazene hydrogel beads for drug controlled release
Authors: Qiu Liyan 
Published: December 2002

AbstractNovel water‐soluble polyphosphazene containing carboxylatophenamino groups (PCPAP) was synthesized by the substitution reaction of ethyl p‐amino benzonate with poly(dichlorophosphazene), followed by alkali hydrolysis. Characterizations by IR, 1H‐NMR, differential scanning calorimetry, and elemental analysis indicated that the reaction brought about an almost complete introduction of carboxylatophenamino to the polymer side chain. Calcium‐crosslinked PCPAP hydrogel beads were accomplished with an extremely mild method. The erosion experiments were conducted in vitro in various pH environments. The erosion duration of the beads at pH 7.4 and 37°C was effectively extended by an increase in the concentration of the PCPAP or CaCl2 solution during the preparation process. Moreover, the bead erosion was sensitive to the pH. The sample dissolved 39.4% in a pH 8.0 buffer within 34 days but only 5.3% in a pH 5.0 buffer. Furthermore, PCPAP underwent degradation into macromolecular segments through the breaking of the backbone, and this could prevent accumulation in the body. These properties of PCPAP may be useful for controlled drug delivery, including intestine‐specific oral delivery systems. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 986–992, 2003
Thermoplastic polymers as modifiers for urea‐formaldehyde (UF) wood adhesives. I. Procedures for the preparation and characterization of thermoplastic‐modified UF suspensions
Authors: Rachtanapun P. , Heiden P. 
Published: December 2002

AbstractAcrylic thermoplastic copolymers with different degrees of hydrophilicity were prepared and introduced into a commercial aqueous urea‐formaldehyde (UF) suspension at 5–10% w/v. The most hydrophilic acrylic thermoplastic was introduced into the UF suspension as an aqueous solution, whereas the most hydrophobic acrylic was introduced as a surfactant‐stabilized suspension. Acrylics with intermediate hydrophilicity were introduced into the UF suspension as a self‐dispersed aqueous suspension. The thermoplastic‐modified UF suspensions with 5% thermoplastic (58% solids) had a viscosity at 30°C of ∼ 114 cP, compared with a viscosity of ∼112 cP for the original UF suspension (60% UF solids). At 10% thermoplastic (63% solids), all the thermoplastic‐modified UF suspensions exceeded 200 cP. The viscosity of the UF suspension modified with self‐dispersed thermoplastic was reduced by ∼ 50% by reducing the thermoplastic molecular weight. SEM micrographs of cured thermoplastic‐modified UF showed phase‐separated thermoplastic domains in a continuous UF phase for the UF modified with self‐dispersed and surfactant‐stabilized thermoplastic, but UF modified with the water‐soluble thermoplastic showed a single phase. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 890–897, 2003
Inhibition of radical polymerization in solvent‐based systems (security of solvent‐based radical polymerization of PSA‐acrylic in a plant reactor)
Authors: Czech Zbigniew 
Published: December 2002

AbstractThis article shows the influence of some chain‐transfer agents as inhibitors for acrylic solvent‐based polymerization. These chain‐transfer agents can offer significant advantages, as outlined below. The following chain‐transfer agents were studied to stop or slow down the polymerization process in the case of a runaway: n‐dodecyl mercaptan, trimethylolpropane‐trimercaptoacetate, phenothiazine, diphenylphenylen diamine, cuprum oxide, isopropanol, toluene, and carbon tetrachloride. Synthesized pressure‐sensitive adhesive based on acrylic polymers and containing 2‐ethylhexyl acrylate, methyl acrylate, and acrylic acid were used for the production of self‐adhesives with high cohesion. The polymerization was accomplished in ethyl acetate. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 1354–1357, 2003