bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of the Flow Rate of H2 in the Reduction Process on the Physical and Catalytic Properties of H2-Reduced Pt/MoO3
Authors: Matsuda Takeshi , Hanai Ayako , Uchijima Fumiko , Sakagami Hirotoshi , Takahashi Nobuo 
Published: September 2002

Abstract
The surface area of H2-reduced Pt/MoO3 decreased with increasing the flow rate of H2 in the reduction process at 773 K, while the opposite tendency was observed at 523 and 623 K. The surface area was found to depend on the extent of reduction, which was raised by an increase in the H2 flow rate. The largest surface area, about 300 m2 g-1, was obtained at a reduction degree of 64%. A study of reduction with a mixture of H2 and H2O showed that the extent of reduction declined in the presence of H2O. We suggest from these results that the reduction of Pt/MoO3 was prohibited by the action of H2O produced by the reduction. The pentane isomerization activity of H2-reduced Pt/MoO3 was also dependent on the extent of reduction. The highest isomerization activity was obtained at a reduction degree of 76%. H2-reduced Pt/MoO3 exhibited a comparable catalytic activity for pentane isomerization to Pt/H-mordenite.
Dynamics of Molecules and Clusters Studied by Low-Temperature Matrix-Isolation Infrared Spectroscopy and Density-Functional-Theory Calculations
Authors: Nakata Munetaka 
Published: September 2002

Abstract
This article presents an account of applications of low-temperature matrix-isolation (MI) infrared spectroscopy combined with density-functional-theory (DFT) calculations to studies of dynamics of molecules and clusters. The MI technique using a conventional Fourier transform infrared (FTIR) spectrophotometer can measure infrared spectra of less stable isomers, clusters produced by photolysis or supersonic-jet expansion, electronically excited species, and unstable radicals. The observed wavenumbers are compared with the calculated values obtained by the DFT calculation and are used for accurate identification of the structures, including conformations around some rotational axes. Thus photoreaction mechanisms of molecules and clusters are elucidated.
Structures and Magnetism of Cyanide-Bridged Bimetallic Compounds: Design of Complex-Based Magnetic Materials
Authors: Okawa Hisashi , Ohba Masaaki 
Published: September 2002

Abstract
This account concerns the synthesis, structures and magnetism of cyanide-bridged bimetallic network compounds. The study aims at the development of molecular-based magnetic materials. Different network structures, from one-dimensional to three-dimensional, are synthesized by the reaction of [M(CN)6]n- with a cationic constituent such as [Ni-(diamine)2]2+, [Ni(triamine)]2+, [Mn(salen)]+, [Mn(en)]2+, etc., in the absence or presence of an appropriate counter ion. Magnetostructural studies for those bimetallic compounds have clarified fundamental factors contributing to magnetic ordering in bulk, magnetic nature (ferromagnetism or metamagnetism) and magnetic phase-transition temperature (Tc). The strategies for gaining high Tc magnetic material and modulating magnetic nature by a change in network structure are described.
Multielement and Morphological Characterization of Industrial Waste Incineration Fly Ash as Studied by ICP-AES/ICP-MS and SEM-EDS
Authors: Fujimori Eiji , Shiozawa Ryuji , Iwata Seiko , Chiba Koichi , Haraguchi Hiroki 
Published: September 2002

Abstract
The leachabilities of major-to-ultratrace elements in industrial waste incineration fly ash (IWIFA) were determined by inductively coupled plasma atomic emission spectrometry (ICP-AES) and inductively coupled plasma mass spectrometry (ICP-MS) in order to characterize IWIFA. The leaching data of about 50 elements in the IWIFA sample could be obtained in the concentration range from mg g-1 to sub-µg g-1, when HNO3 and aqua regia were used as the leachants. In addition, morphological observations of IWIFA particles were performed by a scanning electron microscope with an energy dispersive X-ray spectrometer (SEM-EDS) before and after the leaching treatment of the IWIFA samples. From the data for the leaching and morphological observations, the chemical states of the elements in IWIFA were elucidated as follows: (i) core materials of fly ashes were mostly composed of stable oxides of major elements such as Si, Al, Ti, and Fe; (ii) Cu, Zn, Mo, Cd, and Bi were mainly adsorbed on the surface of fly ash particles in the forms of acid soluble compounds; (iii) Mn, Co, Ni, and Pb were partly taken into the core materials of fly ash particles, and partly adsorbed on the fly ash particles; and (iv) Sb, Cr, Sn, In, and W were contained as rather stable compounds in IWIFA.
Volumetric Properties of Surfactant in Water and in Mixed Solvent from Sound Velocity and Density Measurements
Authors: Nishikawa Sadakatsu , Huang Hua 
Published: September 2002

Abstract
A simple, automatic and economic apparatus was constructed for a precise measurement of sound velocity using a resonance method. It gives the sound velocity value with an accuracy of less than 3×10-3% (±2 cm s-1). Sound velocity and density measurements were carried out in aqueous solutions of several compounds of alkyltrimethylammonium bromide (C1TAB, C8TAB, C10TAB, C12TAB, C14TAB, and C16TAB, where Ci is the number of carbons in straight-chain hydrocarbon groups) at 25 °C. Also, the measurements for C12TAB in a mixed solvent with water and 2-propanol were performed. The critical micelle concentrations (CMC) were determined from the inflection point of the compressibility and electric conductivity. The partial molar adiabatic compressibility (κm* ) and the partial molar volume (Vm*) for the surfactant were determined below and above CMC in water and in the mixed solvent from the apparent molar quantities. The partial molar quantities were also found to be dependent on the concentrations of the added alcohol. These results were interpreted from the points of view of the surfactant conditions and solvent structures.
Asymmetric Photolysis of 2-Phenylcycloalkanones with Circularly Polarized Light: A Kinetic Model for Magnetic Field Effects
Authors: Kohtani Shigeru , Sugiyama Masahide , Fujiwara Yoshihisa , Tanimoto Yoshifumi , Nakagaki Ryoichi 
Published: September 2002

Abstract
Magnetic field effects (MFE) on asymmetric photolysis involving a biradical intermediate have been investigated on a kinetic model where an intersystem crossing (ISC) of the intermediate is taken into account. Changes in the enantiomeric excesses (ee) of chiral substances with circularly polarized light (CPL) irradiation have been simulated, and the necessary conditions for observing the MFE were obtained. The asymmetric photolysis of racemic 2-phenylcycloalkanones (2-PCAs) with CPL has been carried out in both the presence and absence of a magnetic field. Since the anisotropy g factors of 2-PCAs are considerably large, the CPL-induced ee are achieved to a few percent after 90% decomposition though the MFE are not observed. The photolysis mechanism of 2-PCAs in an air-saturated solution has been also clarified. Triplet acyl–benzyl biradicals, formed via photochemical α-cleavage of 2-PCAs, react with O2 dissolved in the solution and result in the formation of acetophenone and alkenoic acids. The bimolecular reactions are diffusion-controlled and the rates are comparable to those of ISC to the singlet biradicals for all 2-PCAs. The recombination yields of the biradicals are sufficiently large. However, the biradical ISC rate shows little magnetic field dependence, which explains the absence of the MFE in this asymmetric photolysis.
Ultrasonic Effects on Electroorganic Processes. Part 22. Cathodic Crossed Hydrocoupling of Acetone with Acrylonitrile
Authors: Atobe Mahito , Fujiwara Sou , Nonaka Tsutomu 
Published: September 2002

Abstract
The ultrasonic effects on the cathodic-crossed hydrocoupling of acetone with acrylonitrile were examined. The total current efficiency of all products in the cathodic reduction of a mixture of acetone and acrylonitrile was little influenced by ultrasonic irradiation, while the product selectivity for crossed hydrocoupling products formed in the cathodic reduction was significantly increased by irradiation. This ultrasonic effect could be rationalized as being due to mass-transport promotion of acrylonitrile molecules as an electrophile to the cathode surface from the bulk of the electrolytic solution by the ultrasonic irradiation. Thus, the ultrasonic effect can be purposively applied to control the product selectivity in the crossed coupling reaction.
Structural Change by Chemical Substitution. Crystal Structures of Acid Salts of p-Nitrobenzoic Acid and Cyclic Secondary Amines
Authors: Moritani Yoshimitsu , Kashino Setsuo 
Published: September 2002

Abstract
The crystal structures of pyrrolidinium hydrogen bis(p-nitrobenzoate) (I), piperidinium hydrogen bis(p-nitrobenzoate) (II), and perhydroazepinium hydrogen bis(p-nitrobenzoate) (III) have been determined by an X-ray diffraction method in order to study an effect of the ring size of the cyclic secondary amines on the crystal structures. There is a close similarity among the crystal structures of I – III, because the schemes of the O–H···O and N–H···O hydrogen bonds are similar in these crystals. It has been found that the space group P21/c of I descends to its subgroup P1- with an occurrence of two formula units in II and ascends to its supergroup C2/c with an occurrence of disorder in III. Such a supergroup-subgroup relationship would make it possible to assume the structure after a transformation caused by chemical substitution.
Estimation of Transition Temperature of Pharmaceutical Polymorphs by Measuring Heat of Solution and Solubility
Authors: Urakami Koji , Shono Yasushi , Higashi Atsuya , Umemoto Kazuichi , Godo Masayuki 
Published: September 2002

Abstract
The transition temperature for enantiotropic polymorphs of pharmaceutical drugs was estimated by measuring the heat of solution and solubility at 25 °C. Instead of the conventional estimation method using van’t Hoff plots, a thermodynamic formula was derived with the heat of solution and solubility as variables for calculating the temperature at which the Gibbs free energy difference between two polymorphs in enantiotropic system become zero. The transition temperatures of polymorphic pairs for five model compounds (seratrodast, mefenamic acid, sulfathiazole, acetazolamide, and carbamazepine) calculated by the formula were in good agreement with previous studies. Since this formula requires solubility data at only one arbitrary temperature other than the heat of solution data for both polymorphs in a polymorphic pair, the proposed method is much faster than the conventional method, requiring solubility data at five or more different temperatures for preparing van’t Hoff plots.
Photoinduced Electron Transfer from Aromatic Aldehyde Hydrazones to Triplet States of C60 and C70; Electron-Mediating and Hole-Shifting Systems
Authors: Ito Osamu , Sasaki Yoshiko , El-Khouly Mohamed E , Araki Yasuyuki , Fujitsuka Mamoru , Hirao Akiko , Nishizawa Hideyuki 
Published: September 2002

Abstract
Photoinduced electron transfer of fullerenes such as C60 and C70 in the presence of aromatic aldehyde hydrazones (AAH’s) has been studied by the nanosecond laser photolysis which measures the transient absorption spectra in the visible and near-IR regions. Electron-transfer takes place from AAH’s to the triplet states of fullerenes; the rates and efficiencies of electron transfer are strongly affected by the electron-donor ability of AAH’s as evaluated by their oxidation potentials. The absorption bands of the radical cations of AAH’s appeared in the near-IR reagion, indicating that the radical-cation center (hole) delocalizes in the entire region of each AAH. On addition of a viologen dication to C60/C70–AAH, the electron of the anion radical of fullerenes moves to viologen dication yielding the viologen radical cation. In the systems of octaethyl porphyrinatozinc (ZnOEP)–C60/C70–AAH, the hole shift was observed from the radical cation of ZnOEP, which was produced by photoinduced electron transfer from the triplet state of ZnOEP to C60/C70, to AAH.
Selective Synthesis, Characterization, and Configurational Flexibility of the Coordinatively Unsaturated Metal Center of Half-Sandwich Type Complexes with the Less-Hindered Hydrotris(3, 5-dimethyl-4-X-1-pyrazolyl)borate Ligands [TpMe2,XMII(κ2-O,O′-L)] (M = Ni, Co; L = NO3, OAc; X = Me, H, Br)
Authors: Hikichi Shiro , Sasakura Yasuyuki , Yoshizawa Michito , Ohzu Yoshiko , Moro-oka Yoshihiko , Akita Munetaka 
Published: September 2002

Abstract
The selective synthesis of half-sandwich type complexes of Ni(II) and Co(II) with the less-hindered hydrotris(3,5-dimethyl-4-X-1-pyrazolyl)borate [X = Me (TpMe3; a series), H (TpMe2; b series), and Br (TpMe2,Br; c series)] ligands, [TpMe2,XMII(κ2-O,O′-L)] [L = NO3 (2), OAc (3)], has been achieved by dropwise addition of a THF solution of NaTpMe2,X to an excess amount of ML2 dissolved in MeOH. The solid state structures of the nitrato complexes 2 have been characterized by X-ray crystallography as their solvated form, 2·solv. (solv. = MeCN, MeOH), in which the metal centers have the six-coordinated octahedral geometry. Solvates are readily dissociated from the metal center upon dissolution in non-coordinationg solvents, such as CH2Cl2 and toluene, as well as drying of a solid sample to give the non-solvated five-coordinated species 2. The crystal structure of the non-solvated TpMe2Ni derivative 3bNi consists of a highly distorted trigonal bipyramidal nickel center.
Crystal- and Solution-Structure Characteristics of Ethylenediaminetetraacetatoaluminate(III) and Gallate(III)
Authors: Jung Woo-Sik , Chung Young Keun , Shin Dong Mok , Kim Sun-Deuk 
Published: September 2002

Abstract
The structures of complex anions, [Al(edta)]- and [Ga(edta)]- (H4edta = ethylenediaminetetraacetic acid), were investigated both in the solid state (X-ray crystallography) and in solution (1H and 13C NMR). Two complexes, (NH4)[Al(edta)]·2H2O (1) and (NH4)[Ga(edta)]·2H2O (2), are isostructural in the solid state. In both metal complexes, the central metal atoms are coordinated by six donor atoms (N2O4) in distorted octahedral coordination geometries in which two nitrogen atoms and two oxygen atoms of two acetate groups occupy the equatorial positions, and the axial positions are occupied by two oxygen atoms of two acetate groups. The 1H and 13C NMR spectra of 1 and 2 showed that acetate groups undergo rapid interchanges between the axial and equatorial positions in solution, its rate in D2O being much faster than that in dimethyl sulfoxide(dmso)-d6 for each complex, and its rate for 1 being slower than that for 2. Based on the NMR spectra, the structures of complex anions [Al(edta)]- and [Ga(edta)]- in solution are concluded to be the same as those in the solid state.
Electrochemical and In Situ SNIFTIR Spectroscopic Studies of Palladium(II) and Zinc(II) Schiff Base Complexes: Structural Control of the Electronic Communication between Two Identical Redox Sites
Authors: Wang Xiayan , Deng Zhaoxiang , Jin Baokang , Tian Yupeng , Lin Xiangqin 
Published: September 2002

Abstract
The mechanisms of the electron transfer of S-benzyl-N-(ferrocenyl-1-methyl-methylidene)-dithiocarbazate palladium(II)/zinc(II) complexes [Pd(lsb)2]/[Zn(lsb)2] were studied by cyclic voltammetry, differential pulse voltammetry, digital simulation and in-situ subtractively normalized interfacial Fourier transform infrared (SNIFTIR) spectroelectrochemistry. The results indicate that [Pd(lsb)2], which has a square-planar configuration, involved two consecutive one-electron steps in the redox process, while the tetrahedral configuration of Zn(II) involved a two-electron step. The [Pd(lsb)2] complex exhibits a moderately strong electronic communication between the two-ferrocene moieties, which occurs through the skeleton chain of the ligand due to extensive electron delocalization of the whole molecule during the redox process, while the [Zn(lsb)2] complex shows low electron delocalization, and has two almost identical ferrocene moieties.
Reaction of Magnesium Pinacolone Enolate with Benzaldehyde: Polar or ET Mechanism?
Authors: Yamataka Hiroshi , Shimizu Makoto , Mishima Masaaki 
Published: September 2002

Abstract
The carbonyl-carbon kinetic isotope effect (KIE) and the substituent effect were measured for the reaction of magnesium pinacolone enolate (CH2=C(OMgBr)C(CH3)3, 1) with benzaldehyde. The results were compared with those for lithium enolate (CH2=C(OLi)C(CH3)3, 2). A normal carbonyl-carbon KIE, a medium-sized Hammett ρ value and the results of chemical probe experiments indicated that the reaction of 1 proceeds via the polar mechanism as in the reaction of 2.
Size-Dependent Population of Trivalent Rare Earth Cations (RE3+) in [(RE)2(H2O)2(SbW9O33)(W5O18)2]15-, and Structural Characterization of a Luthetium–Polyoxotungstate Complex [Lu3(H2O)4(SbW9O33)2(W5O18)2]21-
Authors: Naruke Haruo , Yamase Toshihiro 
Published: September 2002

Abstract
The effect of ionic radius of trivalent rare earth cations (RE3+) on the population at two square-antiprismatic sites (Site I and Site II) in [(RE)2(H2O)2(SbW9O33)(W5O18)2]15- was studied by luminescence spectroscopic and X-ray crystallographic measurements in the Eu/Y- and Eu/Lu-mixed systems. The results indicated that a small RE3+ cation favorably occupies Site II where RE3+ is coordinated by four bridging O atoms of [SbW9O33]9- and four terminal O atoms of [W5O18]6-. With the help of a structural characterization of pure [(RE)2(H2O)2(SbW9O33)(W5O18)2]15- (RE = Er, Y, Dy, Eu, Sm), the large occupancy of small RE3+ at Site II was explained by a favorable coordination of [SbW9O33]9- for small RE3+. A trial of the isostructural Lu complex unexpectedly showed formation of a novel [Lu3(H2O)4-(SbW9O33)2(W5O18)2]21- complex which consists of two [Lu(SbW9O33)(W5O18)]12- groups linked by [Lu(H2O)4]3+ with C2 configuration.
Self-Organized Metallo-Helicates and -Ladder with 2,2′-Biphenyldicarboxylate (C14H8O4)2-: Synthesis, Crystal Structures, and Magnetic Properties
Authors: Kumagai Hitoshi , Inoue Katsuya , Kurmoo Mohamedally 
Published: September 2002

Abstract
We report on the hydrothermal synthesis, single-crystal structures and magnetic properties of three one-dimensional coordination polymers employing the 2,2′-biphenyldicarboxylate dianion, (C14H8O4)2-, as the bridging component. [MII(H2O)4(C14H8O4)], where M = Co (1) and Ni (2), consist of helical chains of square-planar MII(H2O)4 bridged by C14H8O4 with each carboxylate group acting as a mono-dentate ligand. The magnetic properties are those of paramagnets (1: C = 3.34(1) cm3 K/mol, μeff = 5.17 μB, θ = -51(1) K; 2: C = 0.985(9) cm3 K/mol, μeff = 2.81 μB, θ = +27(2) K) with an antiferromagnetic exchange for 1 and a ferromagnetic exchange for 2. Cu2(C14H8O4)(H2O)2 (3) is composed of tetracarboxylato-dimeric units bridged into ladders by biphenyl units. The ladders are packed parallel to each other, and narrow channels are present due to insufficient space filling of the biphenyl rings. Its magnetic behavior follows that of a Bleaney–Bowers singlet-triplet model with a gap of 470(10) K.
Half-Metallocene 1-Aza-1,3-butadiene Complexes of Tantalum: Auxiliary Ligand Effects on Controlling Coordination Modes of 1-Aza-1,3-butadiene Ligand
Authors: Matsuo Yutaka , Mashima Kazushi , Tani Kazuhide 
Published: September 2002

Abstract
We prepared some half-metallocene complexes of tantalum bearing ortho-substituted aryl derivatives of 1-aza-1,3-butadiene ligand. The coordination mode of the 1-aza-1,3-diene (abbr. AD) ligand highly depended on the substituent(s) on the aryl group of the AD ligand and also on the metal center. The number of methyl substituents on the aryl group of the AD ligand differentiated two coordination modes: one methyl substituent, TaCl2Cp*(η4-supine-o-Tol-AD) (1) (Cp* = pentamethylcyclopentadienyl; o-Tol-AD = 1-(2-methylphenyl)-4-phenyl-1-aza-1,3-butadiene), favored an η4-supine-coordination mode, while two methyl substituents, TaCl2Cp*(η2-C, N-Xyl-AD) (5) (Xy1-AD = 2,6-dimethylphenyl-4-phenyl-1-aza-1,3-butadiene), adopted an η2-C, N-imine coordination fashion. Furthermore, the preferential coordination mode of the AD ligand was delicately affected by the substituent(s) on the tantalum center. Dialkylation of 1 led to the formation of TaR2Cp*(o-Tol-AD) (6: R = Me; 8: R = CH2Ph) in the dimethyl complex 6. The equilibrium between η4-coordination mode and η2-C, N-coordination one was observed and the latter mode was thermally more feasible in solution and as solid state, and the o-Tol-AD ligand predominantly coordinated in an η2-C, N-imine fashin to the tantalum center of 8. In contrast, the monobenzylation of 1 did not change the η4-supine coordination mode, giving a monobenzyl complex Cp*TaCl(CH2Ph)(η4-supine-o-Tol-AD) (9). The dibenzyl complex 8 gradually turned to a benzylidene complex Ta(=CHPh)Cp*(η4-supine-o-Tol-AD) (10) on heating at 70 °C with the change of the coordination mode from η2 to η4. Introduction of a 1,3-butadiene ligand to the metal center gave a mixed-ligand complex TaCp*(η2-C,N-o-Tol-AD)(η4-s-cis-1,3-butadiene) (12), in which the metal center adopted an η2-C,N-fashion.
Size Distribution of Dew Droplets and Dew Formation Effect on Deposition Fluxes
Authors: Takeuchi Masaki , Hasegawa Tetuo , Okochi Hiroshi , Igawa Manabu 
Published: September 2002

Abstract
Dew droplets have a distribution of sizes up to 1.5 mm diameter. Large-sized droplets controlled the dewwater amount and the number of small-sized droplets decreased during the evaporation process. The wetting by dew formation enhances the dry deposition of air pollutants.
Synthesis of Methyl O-α-D-Mannosyl-(1→4)-[(3-O-methyl-α-D- mannosyl)-(1→4)-]n3-O-methyl-α-D-mannosides (n = 0, 1, and 2) via Dehydrative Glycosylation
Authors: Hirooka Motoko , Terayama Megumi , Mitani Emi , Koto Shinkiti , Miura Asako , Chiba Kayo , Takabatake Ayano , Tashiro Takako 
Published: September 2002

Abstract
Methyl O-α-D-mannopyranosyl-(1→4)-[(3-O-methyl-α-D-mannopyranosyl-(1→4)-]n3-O-methyl-α-D-mannopyranosides (n = 0, 1, and 2), the lowest homologs related to the 3-O-methylmannose polysaccharides (MMP) from Mycobacterium smegmatis, were synthesized via dehydrative glycosylation reactions. The reagent systems, composed of p-nitrobenzenesulfonyl chloride, silver trifluoromethanesulfonate, and triethylamine, of p-nitrobenzenesulfonyl chloride, silver trifluoromethanesulfonate, and 1, 8-diazabicyclo[5.4.0]undec-7-ene, and of trimethylsilyl trifuloromethanesulfonate and pyridine were useful.
New Dolabellane-Type Diterpenoids from the Okinawan Soft Coral of the Genus Clavularia
Authors: Iguchi Kazuo , Sawai Hisako , Nishimura Hiroto , Fujita Minako , Yamori Takao 
Published: September 2002

Abstract
Two new diterpenoids, 2 and 4, having a dolabellane skeleton were isolated from the Okinawan soft coral of the genus Clavularia. Their structures were determined based on spectroscopic analysis, chemical conversion and X-ray crystallographic analysis. One of these diterpenoids showed cytotoxic activity against tumor cells.