bluuebunny/crossref_metadata_2025_split huggingface dataset:
Structure Sensitivity of Platinum Catalysts for Decomposition Reaction of Diluted NO
Authors: Furusawa Takeshi , Aika Ken-ichi 
Published: September 2002

Abstract
Decomposition reactions of diluted (0.1%) NO without reductants were studied over alumina supported platinum catalysts with various platinum loadings. Supported catalysts with different dispersions of platinum particle (different particle sizes) were prepared by controlling platinum loading on alumina. The XRD measurements disclosed that the relative peak intensity of (111) layer increased with an increase in the particle size, suggesting that the XRD peak intensity was closely related to the surface structure of platinum particles. The activities (TOF) of NO decomposition increased with an increase in the particle size or the peak intensity of (111) structure. Temperature programmed desorption (TPD) of oxygen was also studied on these samples. The temperature of oxygen desorption decreased with an increase in the particle size or the ratio of (111) structure. The NO decomposition was reasonably explained, as it preceded more easily on the (111) surface where oxygen was weakly adsorbed on platinum. It was also pointed out that the surface structure was more sensitive for oxygen adsorption than the NO decomposition reaction.
Vibrational Relaxation of Chemically Excited SiO (ν = 1—5) Produced in the Reaction of Silane with O(1D)
Authors: Takahara Atsuko , Tezaki Atsumu , Matsui Hiroyuki 
Published: September 2002

Abstract
The state-resolved vibrational relaxation process of SiO was monitored in the excimer laser photolysis of N2O/SiH4/He mixtures, where vibrationally hot SiO (Tv = 5200 K) was produced by the reaction of SiH4+ O(1D). A frequency-doubled optical parametric oscillator was used as a widely tunable source to probe SiO (v = 0—7) by the laser-induced fluorescence technique. From an analysis of the observed relaxation profiles, the vibrational transition rate constants in collisions with He and N2O were evaluated against the vibrational level v = 1—5 of SiO. Previous theories for the V-T and V-V energy transfer were compared with the present experimental results.
Influence of the Naphthalene Derivative on the Luminescence Properties of CdS Particles Prepared by the Sol-Gel Method
Authors: Fujii Tsuneo , Tanaka Nobuaki , Tai Hideyuki , Obara Shiro , Ellis Arthur B 
Published: September 2002

Abstract
Adsorption from an ethanol solution of naphthalene (N) derivatives onto the surface of CdS particles encapsulated into silica glasses prepared by the sol-gel method quenches or enhances the yellow-green and red photoluminescence (PL) intensity of the semiconductor particle relative to its value in pure ethanol solvent. The enhancement is in the order 1,4-dimethyl-N &gt; 1-chloro-N ≥ N ≥ 1-fluoro-N ≥ 1-methyl-N ≥ 1-bromo-N and quenching is in the order 1-nitro-N &gt;2-carboxy-N. This order is understandable based on the electron-donating or electron-accepting abilities of the individual naphthalene derivatives. The changes in the PL intensity depend on the concentration and give good fits to the Langmuir adsorption isotherm model, yielding equilibrium constants for adduct formation on the order of ca. 103 M-1.
Magneto-Structural Correlations in Phenoxo-Bridged Metal(II) Compounds. Magnetic Properties of (R4N)2[Co2Cl4(4-XC6H4O)2] (X = H, CH3; R = CH3, C2H5)
Authors: Emori Shuji , Nakashima Michio , Mori Wasuke 
Published: September 2002

Abstract
Dinuclear compounds (R4N)2[Co2Cl4(4-XC6H4O)2] (X = H, CH3; R = CH3, C2H5) were prepared, and their temperature-variable magnetic susceptibilities were determined to evaluate the exchange-coupling strength's between the cobalt(II) ions. The coupling strength of (Et4N)2[Co2Cl4(4-CH3C6H4O)2] was considered in terms of its structural parameters and the electronic effects of the methyl substituent. Such magneto-structural correlations, together with those for copper(II), nickel(II), and iron(II) systems, confirm that the exchange couplings in phenoxo-bridged metal(II) compounds are affected concurrently by the s/p character of the hybrid orbitals on the bridging oxygen atom, by the electronic effects of the substituents on the aromatic ring, by the ionic radius and acidity of the metal(II) ion, as well as by the number of unpaired electrons and d character of the hybrid orbitals on the metal(II) ion.
Conversion of Methane to Methanol on Diiron and Dicopper Enzyme Models of Methane Monooxygenase: A Theoretical Study on a Concerted Reaction Pathway
Authors: Yoshizawa Kazunari , Suzuki Akiya , Shiota Yoshihito , Yamabe Tokio 
Published: September 2002

Abstract
We present theoretical analyses for the conversion of methane to methanol on a diiron model of soluble methane monooxygenase (sMMO) and on dicopper models of particulate methane monooxygenase (pMMO) using the hybrid density-functional-theory B3LYP method. Methane is proposed to be reasonably converted into methanol in a two-step concerted manner on the dinuclear enzyme models. The first step in our proposal is concerted H atom abstraction of methane via a four-centered transition state (TS1) and the second step is concerted methyl migration via a three-centered transition state (TS2). The general features of the electronic process are identical to those of the gas-phase process for the methane-methanol conversion by the bare FeO+ complex. The concerted H atom abstraction and the direct H atom abstraction via a transition state with a linear C-H-O(Fe) array are compared using the dinuclear models. The transition state for the direct H atom abstraction (TSd) on the diiron model is found in the spin undecet state; however, that on the dicopper models is found in the doublet state. Kinetic isotope effects (kH/kD) are calculated and analyzed for the concerted and the direct H atom abstraction mechanisms using the transition state theory. Calculated kH/kD values for the concerted process and the direct process are 9 and 14, respectively, at 300 K.
Phase Separation Behavior of (Palmitic Acid/Lignoceric Acid) Mixed Monolayer Based on a π-A Isotherm Measurement and a Scanning Probe Microscopic Observation
Authors: Kuramori Miyuki , Uchida Naoko , Suehiro Kazuaki , Oishi Yushi 
Published: September 2002

Abstract
The aggregation state of a mixed monolayer of palmitic acid (C16) and lignoceric acid (C24) was investigated on the basis of a π-A isotherm measurement and a scanning probe microscopic observation. The independence of the plateau and collapse pressures on the monolayer composition and the additivity of the average molecular area exhibited that the C16 and C24 molecules were immiscible in the monolayer, indirectly suggesting the presence of phase-separated domains in the system. Two kinds of regions with different heights were apparently observed on an atomic force microscope image of the mixed monolayers. The change in the area fraction with the composition, the film thickness and the difference in the lateral force of the two regions revealed that the (C16/C24) mixed monolayer was in a phase-separated state. This phase separation is probably due to an enthalpic contribution based on the difference in cohesive energy of each alkyl chain.
Temperature-Induced Phase Transitions in 1,3,5-Trimethylbenzene Crystal
Authors: Yamazaki Michiko , Tanaka Makiko , Inoue Tohru , Suzuki Yoshio , Nibu Yoshinori , Shimada Hiroko , Shimada Ryoichi 
Published: September 2002

Abstract
The temperature effect on the Raman-active inter- and intramolecular vibrations of 1,3,5-trimethylbenzene crystal was studied. The spectral structure due to the intermolecular vibrations changed as the temperature was varied and the vibrational frequencies shifted discontinuously at about 95 and 195 K when the temperature rose from 77 K. For the intramolecular vibrations, a discontinuous shift of the vibrational frequencies of the ν1 and ν12 modes was observed at about 95 K. Thermograms obtained with a differential scanning calorimetry for the crystal show two endothermic peaks at 91 and 188 K as well as three endothermic peaks at 220, 222, and 227 K around the melting point. These observations indicate that the first-order phase transitions take place at 91 and 188 K under 1 atm in a 1,3,5-trimethylbenzene crystal, and that the crystal has three different crystal structures around the melting point between 220 and 227 K.
Intermolecular Interactions in Crystal Structures of Isomeric Mesogens with Two Ester Linkages
Authors: Tamura Kyoko , Hori Kayako 
Published: September 2002

Abstract
In order to make clear the influence of more than one polar group on packing modes of molecules and hence on liquid crystalline behavior, crystal structures have been determined for five mesogens with a general formula, CnH2n+1O-C6H4-X-C6H4-Y-C6H4-OCmH2m+1: I (n = m = 8, X = COO, Y = OCO), II (n = m = 8, X = OCO, Y = COO), VI (n = 8, m = 1, X = COO, Y = OCO), V (n = 8, m = 1, X = OCO, Y = COO), and VI (n = 8, m = 1, X = OCO, Y = OCO). Two symmetrical molecules I and II, in which the dipole moments cancel, have quite different crystal packings. Compounds II and V with the same core (the moiety except for chains) have similar packing modes in spite of different chain lengths. These facts are interpreted in terms of two factors: overlappings of planar moieties in cores, formed by the conjugation of a benzene ring with the attached ester linkage(s), and dipole-dipole interaction of polar groups. The crystal structures are closely related to the liquid crystalline phase sequences: imbricated structures (half-and-half overlapping of molecules) to the nematic character and smectic-like layer structures with the smectic one.
Behaviors of the One-Electron Reduction Species of {RuNO}6-Type Complexes. An Oxygen-Transfer Reaction Occurs in the Nitrosyl Site of cis-[Ru(NO·)X(bpy)2]n+ (X = ONO2 for n = 1, X = CH3CN, H2O for n = 2) ({RuNO}7-Type) to Give an Identical Nitro Species
Authors: Mukaida Masao , Sato Yoshinobu , Kato Hideji , Mori Mami , Ooyama Dai , Nagao Hirotaka , Howell F Scott 
Published: September 2002

Abstract
Degradation sequences of cis-[Ru(NO·)X(bpy)2]n+ (X = ONO2, OCHO, OCOMe, NO2, Cl for n = 1; X = CH3CN, H2O for n = 2) ({RuNO}7-type), a one-electron reduction species of {RuNO}6-type complexes, were investigated in CH3CN by monitoring using electrochemical techniques (both cyclic and hydrodynamic voltammetries). The results show that an oxygen transfer occurs effectively at the nitrosyl site of cis-[Ru(NO·)X(bpy)2]n+ (X = ONO2 for n = 1, X = CH3CN, H2O for n = 2) to give identical nitro species, cis-[Ru(NO2)(CH3CN)(bpy)2]+. The extent that the nitrosyl-to-nitro conversion proceeded, however, differs depending on the X ligands; X = CH3CN and H2O complexes gave the nitro species in almost 40% yield, while X = ONO2 complex afforded nearly 80%. The monitoring results of the degradation sequences, along with the differences in yields, suggest that different processes are operating separately in the oxygen-transfer reaction. We propose some possible processes for both reactions, although a further investigation is needed for a detailed explanation.
An Analysis of S-T0 Mixing Polarization of CIDEP in Terms of the Lennard-Jones Fluids: 1-Hydroxy-1-methylethyl Radical in 2-Propanol
Authors: Kitahama Yasutaka , Kimura Yoshifumi , Hirota Noboru 
Published: September 2002

Abstract
Calculations of the magnitudes of the polarization (PRPM) due to singlet-triplet (S-T0) mixing of the radical pair mechanism of chemically induced dynamic electron polarization (CIDEP) are made by numerically solving the stochastic Liouville equations for fluids in which intermolecular interactions are represented by the Lennard-Jones (LJ) potentials. PRPM and the relation between PRPM and the difference in the resonance frequencies of radicals of the pair (2Qab) are examined for the continuum and for various models with different relative strengths of solute-solute, solute-solvent, and solvent-solvent interactions.In the continuum, PRPM reaches the maximum value at small |J0| (J0 is the exchange interaction at a distance of the closest approach),and levels off at large |J0|, whereas in the LJ fluids it increases in the region of large |J0| and reaches a second maximum.At low temperatures, m, which is defined as the exponent in the form of PRPM ∝ Qabm, approaches 0 in the LJ fluids in the region of |J0| = 1011—1012 s-1.The calculated results are compared with the experimental results obtained for 1-hydroxy-1-methylethyl radicals in 2-propanol.The main features of the experimental observations are qualitatively better explained by the present models of the LJ fluids than by the continuum with |J0| = 1011—1012 s-1.These results are ascribed to the effect of the solvent structure which tends to keep the solvent-separated radical pair for a longer time.
Interactions of β- and γ-Cyclodextrins with Thionine and 2-Naphthalenesulfonate in Aqueous Solution
Authors: Hamai Sanyo 
Published: September 2002

Abstract
In aqueous solutions, a cationic dye, thionine (Th), has been found to form a 1 : 1 complex with 2-naphthalenesulfonate (2NS), which is an organic anion. An equilibrium constant for the formation of the complex has been evaluated to be 310 ± 20 mol-1 dm3 from the absorbance change of Th.The Th fluorescence is quenched by the formation of the complex. β-Cyclodextrin (β-CD) and γ-CD form a 1 : 1 and a 1 : 2 host-guest inclusion complex with Th, respectively.Equilibrium constants for the formation of the 1 : 1 β-CD-Th and 1 : 2 γ-CD-Th inclusion complexes have been evaluated to be 300 ± 20 mol-1 dm3 and 1.07 × 107 mol-2 dm6, respectively.The addition of γ-CD to a Th solution containing 2NS results in the formation of a 1 : 1 : 1 γ-CD-Th-2NS inclusion complex. From a simulation concerning the absorbance change, the equilibrium constant for the formation of the ternary 1 : 1 : 1 inclusion complex has been estimated to be 22600 mol-1 dm3, which is nearly the same as that (21500 mol-1 dm3) estimated from a simulation concerning the fluorescence intensity change.
Effect of High Magnetic Field on Copper Deposition from an Aqueous Solution
Authors: Tanimoto Yoshifumi , Yano Hiroshi , Watanabe Sin-ichi , Katsuki Akio , Duan Wenyong , Fujiwara Masao 
Published: September 2002

Abstract
Deposition of copper metal from a Cu2+/Zn liquid-solid redox reaction is studied in a high magnetic field gradient. A zinc wire is placed on a chromatography paper strip with a copper(II) chloride aqueous solution. At zero field, copper dendrite grows uniformly around the wire. In the presence of a magnetic field gradient (ca. 410 T2 m-1), the dendritic pattern changes drastically. The yields of copper dendrite and consumed copper ion increase by ca. 50% in the magnetic field. The results are interpreted in terms of the magnetic force-induced convection of the solution.
Cage Dynamics in the Third-Order Off-Resonant Response of Liquid Molecules: A Theoretical Realization
Authors: Okumura Ko , Bagchi Biman , Tanimura Yoshitaka 
Published: September 2002

Abstract
It is generally believed that the ultrafast initial spectroscopic response from the molecules in the condensed phase originates from small amplitude inertial motions within the cage formed by the nearest-neighbor solvent molecules surrounding the probe, or the cage effect. However, no quantitative estimate of this dynamics has been available for the currently popular experiments which measure the third-order off-resonant response. In this work, we fill this gap by a microscopic approach and demonstrate that the cage dynamics alone can produce the initial rise in the subpicosecond (ca. 200 fs) range in the third-order response. A simple analytical expression for the initial Gaussian time constant relevant to various kinds of the third-order off-resonant experiments is presented, which is found to be rather strongly dependent on the temperature. Connection with the non-polar solvation dynamics is also discussed.
Calorimetric and Magnetic Studies on a Ferromagnetic Phase Transition of the Metal-Assembled Complex MnCu(obbz)·H2O
Authors: Asano Kaori , Miyazaki Yuji , Mori Wasuke , Nakatani Keitaro , Kahn Olivier , Sorai Michio 
Published: September 2002

Abstract
Heat capacities of the metal-assembled ferromagnet MnCu(obbz)·H2O (obbz = oxamidobis(benzoato)) have been measured in the temperature region between 0.1 and 301 K by adiabatic calorimetry. A broad phase transition due to the three-dimensional ferromagnetic ordering was observed around 17 K. Above the transition temperature, a heat capacity tail arising from the short-range order characteristic of a low-dimensional magnet was found. The enthalpy and entropy gained by the phase transition are 227 J mol-1 and 12.7 J K-1 mol-1, respectively. This entropy acquisition is very close to the value Rln 5 ( = 13.4 J K-1 mol-1) expected for the spin manifold of the spin quantum number S = 2 ground state, where R stands for the gas constant. The thermal anomaly above the transition temperature can be accounted for in terms of the S = 2 two-dimensional ferromagnetic Heisenberg model rather than the one- or three-dimensional models. This suggests that this complex can be regarded as a two-dimensional ferrimagnet, in which strong antiferromagnetic interaction exists between a pair of Mn(II) (S = 5/2) and Cu(II) (S = 1/2) but the magnetic coupling between the pairs is very weak. Magnetic measurements for the complex revealed a bend of the hysteresis loop above the transition temperature and a magnetic relaxation below the transition temperature. These results lead to the conclusion that the broadness of the phase transition may be attributed to superparamagnetism caused by the fact that the present complex is prepared only in a fine powder.
Simultaneous Multielement Determination of Hydride- and Oxoanion-Forming Elements in Seawater by Inductively Coupled Plasma Mass Spectrometry after Lanthanum Coprecipitation
Authors: Yabutani Tomoki , Ji Shan , Mouri Fumihiko , Itoh Akihide , Chiba Koichi , Haraguchi Hiroki 
Published: September 2002

Abstract
The simultaneous multielement determination of trace elements in seawater, especially hydride- and oxoanion-forming elements, has been investigated by inductively coupled plasma mass spectrometry with the aid of lanthanum coprecipitation preconcentration. The optimum pH in lanthanum coprecipitation was pH 9.5; at this value, trace elements were well recovered and major constituents of seawater such as Na, Mg, K, and Ca were significantly reduced in the concentrated solutions. The recovery values obtained for V, Cr(III), Mn, As(III), As(V), Se(IV), Y, Sn, Sb(III), Sb(V), W, Bi, and U were more than 85% after lanthanum coprecipitation, while Cr(VI), Se(VI), and Mo(VI) provided poor recoveries of less than 30%. The reproducibility for coprecipitation was within 5% as relative standard deviation. The present method was applied to the determination of trace elements in coastal seawater reference material CASS-3. The analytical values for Mn, As, V, Y, Sb, W, and U were in fairly good agreement with the certified or literature values.
Preparations and Characterizations of Novel N, N′-Ethylene-Bridged-(S)-Histidyl-(S)-Tyrosine Derivatives and Their Copper(II) Complexes as Models of Galactose Oxidase
Authors: Yamato Kazuhiro , Inada Takanori , Doe Matsumi , Ichimura Akio , Takui Takeji , Kojima Yoshitane , Kikunaga Toshimitsu , Nakamura Shin , Yanagihara Naohisa , Onaka Tomoko , Yano Shigenobu 
Published: September 2002

Abstract
Structurally constrained ethyl (2S)-3-(4-hydroxyphenyl)-2-{[(3S)-3-(imidazole-4-yl)-methyl]-2-oxo-piperazine-1-yl}propionate (N,N′-ethylene-bridged-(S)-histidyl-(S)-tyrosine ethyl ester, eHY-OEt) was obtained by a one-pot reaction from (S)-histidine methyl ester and (S)-tyrosine ethyl ester with glyoxal. Four ligands, (Boc-Gly-eHY-OEt (HL1), Boc-Gly-eHY-NH2 (HL2), Ac-eHY-OEt (HL3), and Ac-eHY-NH2 (HL4), where Boc-Gly is t-butyloxycarbonyl-glycyl and Ac is acetyl) were derived from eHY-OEt. Also, corresponding copper(II) complexes, in which only amino acid side chains coordinate to the copper(II) ion, [Cu(L1-)2(H2O)] 1, [Cu(L2-)2(H2O)] 2, [Cu(L3-)2(H2O)] 3, and [Cu(L4-)2(H2O)] 4, were prepared and characterized by elemental analyses and the FAB-MS spectra. The conformational behaviors were confirmed by the 1H NMR spectra. UV-visible-NIR, CD and ESR spectra showed that copper(II) complexes are mononuclear square-pyramidal structures in both the solid and solution states. Cyclic voltammetry of HL1 and 1 showed irreversible ligand oxidation. The acid-dissociation constants of HL4 were obtained as 6.38 (pKa1) and 9.67 (pKa2) by potentiometric titration, and the complex formation constants of 4 were obtained as 7.16 (log K1) and 3.71 (log K2). Furthermore, thermogravimetric analyses (TGA) and differential thermal analyses (DTA) of 1 and 2 were measured.
Synthesis, Crystal Structures, and Some Properties of S-Bridged Pt(II)-M(III) (M = Co, Rh) Dinuclear Complexes with Square-Planar and Octahedral Geometries
Authors: Yamada Yasunori , Uchida Mamoru , Miyashita Yoshitaro , Fujisawa Kiyoshi , Konno Takumi , Okamoto Ken-ichi 
Published: September 2002

Abstract
A novel dinuclear complex [{Pt(bpy)}{Co(aet)2(en)}]3+ (bpy = 2,2′-bipyridine; aet = 2-aminoethanethiolate; en = ethylenediamine) (1) composed of square-planar and octahedral geometries was obtained by a substitution reaction of [Ni{Co(aet)2(en)}2]4+ with [PtCl2(bpy)]. The reactions of fac(S)-[M(aet)3] (M = CoIII, RhIII) with [PtCl2(bpy)] also gave a similar type of S-bridged dinuclear complexes [{Pt(bpy)}{M(aet)3}]2+ (M = CoIII (2), RhIII (3)). The crystal structures of complexes 1, 2, and 3 were determined by X-ray crystallography. All of the Co and Rh atoms in 1, 2, and 3 take approximately octahedral geometry. The Pt atoms in 1, 2, and 3 are coordinated by two N atoms in bpy and two S atoms from C2-cis(S)-[Co(aet)2(en)]+ or [M(aet)3] unit, and all of them take square-planar geometry. fac(S)-[Co(aet)3] is structurally converted into a mer(S)-[Co(aet)3] unit during the course of producing a [{Pt(bpy)}{M(aet)3}]2+-type dinuclear complex, although fac(S)-[Rh(aet)3] retains its structure. These complexes were characterized on the basis of the electronic absorption, CD, and 13C NMR spectra, together with cyclic voltammetry.
Kinetic Results and Reaction Pathways of Intermolecular Thiolato Ligand Migration between Titanocene Complexes and from Cp2TiX(SAr) (X = Cl, SAr) to PtCl(Me)(cod) (cod = η2,η2-1,5-Cyclooctadiene)
Authors: Osakada Kohtaro , Hosoda Tomoya , Yamamoto Takakazu 
Published: September 2002

Abstract
Cp2TiCl(SPh) (1a), prepared from an equimolar reaction of Cp2TiCl2 with NaSPh, undergoes partial and reversible disproportionation in THF into Cp2TiCl2 and Cp2Ti(SPh)2 (2a). The thermodynamic parameters of the reaction are determined to be ΔH° = 13.0(0.6) kJ mol-1 and ΔS° = 14(2) J K-1 mol-1 at 298 K. An equimolar reaction of Cp2Ti(SAr)2 (2a: Ar = C6H5, 2b: Ar = C6H4Me–p, 2c: Ar = C6H4OMe–p, 2d: Ar = C6H4Cl–p, 2e: Ar = C10H7) with PtCl(Me)(cod) in THF leads to an intermolecular exchange of the thiolato and chloro ligands to afford Pt(Me)(SAr)(cod) (3a: Ar = C6H5, 3b: Ar = C6H4Me–p, 3c: Ar = C6H4OMe–p, 3d: Ar = C6H4Cl–p, 3e: Ar = C10H7). Ti complexes: Cp2TiCl2, Cp2TiCl(SAr), Cp2Ti(SAr)2, and a minor amount of (Cp2TiCl)2O, are also present in the products. Absorption spectra of a solution of 2a and excess PtCl(Me)(cod) exhibit distinct changes due to the thiolato ligand transfer, and indicate initial formation of 1a and its subsequent reaction with the Pt complex to form Cp2TiCl2. The reaction of 1a with excess PtCl(Me)(cod) obeys second-order kinetics to [1a]. The observed rate constants, kobsd, increase with an increase in the concentration of PtCl(Me)(cod). Linear plots of the reciprocal of kobsd versus [1a]0/[PtCl(Me)(cod)]0 are consistent with the reaction pathway involving the disproportionation of 1a into an equimolar mixture of Cp2TiCl2 and 2a, the latter of which readily reacts with PtCl(Me)(cod) to regenerate 1a.