bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ultrafast Energy Transfer Dynamics at Solid/Liquid Interfaces as Investigated by Photothermal Spectroscopy
Authors: Tsuyumoto Isao , Sawada Tsuguo 
Published: September 2002

Abstract
Recent studies on ultrafast energy transfer at solid/liquid interfaces were reviewed, focusing on our developed photothermal techniques: femtosecond transient reflectivity (fs-TR) method, femtosecond transient reflecting grating (fs-TRG) method, and picosecond surface plasmon resonance transient reflecting grating (ps-SPR-TRG) method. Firstly, Pt/auqoues electrolyte interfaces were measured using the fs-TR method. An ultrafast relaxation component of 20 fs was first observed in the Pt/HCl (aq) and Pt/H2SO4 (aq) interfaces, in which the anions (Cl- and SO42-) have strong affinity to the Pt surface. It was suggested that this is due to the scattering of non-thermalized electrons by adsorbed anions. Secondly, TiO2/KSCN (aq) interfaces were measured using the fs-TRG method. Ultrafast relaxation components (110—690 fs) were observed in the TRG signals. This marked the first observation of the contribution of nonequilibrium holes to the energy transfer at TiO2/KSCN (aq) interfaces. Thirdly, Au/NaCl (aq) interfaces were measured using ps-SPR-TRG method, focusing at both the behavior of hot electrons and thermal diffusion. The results indicated that an ultrafast energy transfer process occurs prior to the heat diffusion and this process is hindered by the adsorbed ions.
Conductive Copper Salts of 2,5-Disubstituted N,N′-Dicyanobenzoquinonediimines (DCNQIs): Structural and Physical Properties
Authors: Kato Reizo 
Published: September 2002

Abstract
Structural and physical properties of the Cu salts of a series of π-acceptors N,N′-dicyanobenzoquinonediimines (DCNQIs) are described. The most notable feature of this system is that 3d electrons in Cu interact with pπ electrons in DCNQI near the Fermi level. This unique feature has provided a lot of interesting solid state properties: the Mott transition triggered by the Peierls transition, the pressure-induced metal-insulator transition, the metal-insulator-metal (reentrant) transition, the three-dimensional Fermi surface, the anomalous isotope effects, the antiferromagnetic transition, the weak ferromagnetism, and the electron mass enhancement. The aim of this account is to give an overview of this unique pπ-d system.
Direct Study on the Unimolecular Decomposition of Methoxy Radicals: The Role of the Tunneling Effect
Authors: Oguchi Tatsuo , Miyoshi Akira , Koshi Mitsuo , Matsui Hiroyuki 
Published: September 2002

Abstract
The unimolecular decomposition of methoxy radicals, CH3O + M → CH2O + H + M (1a), has been directly studied by laser photolysis-laser-induced fluorescence method in the temperature range 610—740 K. Nearly linear pressure dependence of the first-order decay rate was observed in the investigated pressure range (100—450 Torr), and the second-order rate constants were derived for He and N2 buffer gases as: k0(He) = 2.8 × 10-9 exp (-84.3 kJ mol-1/RT) cm3 molecule-1 s-1 and k0(N2) = 4.3 × 10-9 exp (-84.1 kJ mol-1/RT) cm3 molecule-1 s-1, respectively. An RRKM calculation with a semiclassical one-dimensional tunneling treatment showed that the tunneling effect is essentially important in the present experimental conditions. The calculation indicates a non-linear pressure dependence of the rate constant even in the classical low-pressure limiting conditions, which is consistent with the experimental observations. The RRKM model (with threshold energy = 101.7 kJ mol-1) derived by the best fit to the experimental results is in good agreement with the theoretical investigations and the microcanonical rate constants measured by the stimulated emission pumping method.
Structure and Reactivity of Amphoteric Oxygen Species
Authors: Ishiguro Katsuya , Sawaki Yasuhiko 
Published: September 2002

Abstract
The structure and chemical properties of 1,3-dipolar peroxidic species (X+-O-O-) such as ozone (X = O), nitroso oxides or nitrenium peroxides (X = RN), carbonyl oxides or carbenium peroxides (X = R2C), and persulfoxides or sulfonium peroxides (X = R2S) have been attracting much attention from synthetic, biological, and theoretical standpoints. These active oxygen species can be classified into two types depending on whether the X+ is an enium (carbenium, nitrenium, silylenium etc.) ion or an onium (ammonium, oxonium, phosphonium, sulfonium etc.) ion, and their reactivities are quite different depending on the nature of X. The individual features as well as the overviews of structure and reactivities of these X-O-O species are reviewed. Ozone and nitroso oxides have an electrophilic character while carbonyl oxides usually act as a nucleophilic oxygen transfer agent, their reactivities being controlled by substituents. It is important to see whether or not XOO species can isomerize to the cyclic isomers. Although cyclic O3 is thermodynamically unstable, dioxiranes, the cyclic form of carbonyl oxides, have been isolated and fully characterized. It has been suggested that nitroso oxides isomerize to the cyclic form yielding the corresponding nitro compounds unimolecularly. In the case of persulfoxides (X = R2S), the dipolar structure (X+-O-O-) is important, their characteristic reaction being nucleophilic O-transfer to sulfoxides, while 3λ5-dioxaphosphirane (X = R3P) can exist only in the cyclic form, showing electrophilic reactivity. Effects of X's on structure and reactivity of these oxides were systematically examined by the density functional BLYP/6-31G* calculations. The inductive effect through σ-framework has been found to dominate the thermodynamic stabilities of carbonyl oxides, while the π-donating property of substituents governs the activation energy for the cyclization to dioxiranes.
Kinetics and Mechanism of Hexachloroplatinate(IV) Reduction by Some Neutralized α-Hydroxy Acids in a Carbonate-Hydrogencarbonate Buffer Medium
Authors: Pal Biswajit , Gupta Kalyan Kali Sen 
Published: September 2002

Abstract
The kinetics of hexachloroplatinate(IV) reduction by some neutralized α-hydroxy acids such as glycolic, lactic, α-hydroxyisobutyric, mandelic, atrolactic, and benzilic acids in a carbonate-hydrogencarbonate buffer medium have been investigated. Platinum(IV) is reduced by the substrates to platinum(II) in a one-step two-electron process, whereas the substrates are oxidized to give formaldehyde, acetaldehyde, acetone, benzaldehyde, acetophenone, and benzophenone for the respective reactions. The pseudo-first-order rate constant is independent of the initial [platinum(IV)] as well as [OH-]. The reaction rate increases with increasing [substrate], but decreases with increasing chloride concentration. The reactions obey the following rate expression:
−d[PtIV]t/dt=(kKe[A−][PtIV]t )/([Cl−]+Ke[A−])·
The reactions proceed through an initial 1 : 1 complex formation between the reactants, followed by decomposition of the complex to give the respective reaction products via C-C bond cleavage. The reactivity of the α-hydroxycarboxylate towards Pt(IV) are as follows: atrolactic acid &gt; mandelic acid &gt; benzilic acid &gt; α–hydroxyisobutyric acid &gt; lactic acid &gt; glycolic acid. Thermodynamic parameters for the decomposition step have been evaluated. The mechanism of the reactions is discussed.
Inhibiting Effects of Group 6 Oxo-Anions on the Pitting Corrosion of Tin in Citrate-Chloride Solution
Authors: Assaf Fawzi Hassan 
Published: September 2002

Abstract
The effect of chloride ions on both anodic dissolution and pitting corrosion of tin metal in the aerated equimolar solutions 0.1 M (1 M = 1 mol dm-3) citrate-chlorid-oxo-anions (CrO42-, WO42-, and MoO42-) has been investigated. Different techniques were used, such as potentiodynamic, potentiostatic polarization, electrochemical impedance spectroscopy techniques. These were complemented by surface examination using scanning electron microscopy. Lower current values in the presence of equimolar (0.1 M) citrate-oxo-anions with addition of Cl- in various concentrations were observed, compared with those obtained in the oxo-anion free solutions. Thus, these oxo-anions might create a certain impediment or barrier to the attack of the aggressive Cl- on the metal surface. However, the addition of the studied anions at lower concentrations (10-3 and 10-2 M) in 0.1 mol dm-3 citrate-chloride, enhanced the active metal dissolution and passivity break down of tin. Retardation to a considerable extent was observed, however, at higher concentrations (5×10-2 and 10-1 M). All measurements using the different techniques, under the same conditions, confirmed that the order of reduced aggressiveness of Cl- was CrO42- &gt; WO42- &gt; MoO42-. This indicates that CrO42- remains the best inhibitor to prevent the pitting corrosion, probably through its ability to repair defects in the oxide film.
Production and Mass-Spectroscopic Characterization of Multiple Metal-Rich Alkali Halide Ion Clusters: Novel Structures and Properties
Authors: Sugai Toshiki , Shinohara Hisanori 
Published: September 2002

Abstract
Multiple metal-rich ion alkali halide clusters from solid crystals of NaF and CsI have been produced and characterized for the first time by a newly developed high-pressure laser-vaporization cluster source. The observed positive metal-rich clusters are NanFm+ (n ≈ 40, n-m = 1—9) and CsnIm+ (n ≈ 60, n-m = 0—5), which have enhanced intensities at n = 14, being independent of m, indicating the existence of multiple excess electrons. For negative clusters, NanFm- (n ≈ 40, n-m = -1—10) and CsnIm- (n ≈ 60, n-m = -2—3) have been observed. The NaF metal-rich negative clusters show two types of distinct magic numbers at n-m = 7 ((NaF)mNa7-) and n = 14 (Na14F13-x-, x = 0—4). The former and latter magic-number ions suggest the existence of a negative core ion of Na7- and a cubic 3×3×3 structure with multiple excess electrons, respectively. The present high-pressure laser-vaporization cluster source is suitable to produce these unstable clusters with a unique stoichiometry.
Studies on Photochemical Reactivities of 2-(Alkylcarbamoyl)quinolines
Authors: Ono Isao , Ikegami Tetsuo , Inayoshi Tomoko 
Published: September 2002

Abstract
The photochemistry of three types of 2-(alklylcarbamoyl)quinolines was studied. The illumination of 2-(diethylcarbamoyl)quinolines (1a, 1b, and 1c) afforded 2-(2-ethylaminopropionyl)quinolines (3a, 3b, and 3c) with a small amount of five-membered cyclic products, 1H-pyrrolo[3,4-b]quinolin-3(2H)-ones (4a, 4b, and 4c), both of which were formed via Type-II hydrogen-atom abstraction from the T1 state. 2-(Ethylcarbamoyl)quinoline (1d) did not undertake any photochemical change. The photochemical inactivity of 1d could be attributed to the unfavorable orientation of its carbamoyl substituent for intramolecular hydrogen-atom abstraction by a ring nitrogen. The illumination of 2-(alkylcarbamoyl)-3-methyl quinolines (2a and 2b) afforded 2-(N-acetyl-N-alkylcarbamoyl)-3-methyl quinolines (5a and 5b), which were suggested to be formed by the atmospheric oxidation of an unstable photoproduct formed via the S1 state.
Electrochemical Preparation of Poly(3-thiopheneacetic acid) and Its n-Type Semiconductor Property
Authors: Hara Kohjiro , Sayama Kazuhiro , Arakawa Hironori 
Published: September 2002

Abstract
3-Thiopheneacetic acid (3TA) was electrochemically oxidized and polymerized on indium tin oxide (ITO) electrodes in a 0.05 mol dm-3 tetrabutylammonium perchlorate (TBAP) acetonitrile solution; also, the photoelectrochemical properties of the resulting poly(3-thiopheneacetic acid) (P3TA) were studied. The film showed n-type semiconductor properties, although anion-doped conducting polymer prepared by electrochemical oxidation is generally of the p-type. An anodic photocurrent due to oxygen evolution from water was observed under white-light irradiation in a 0.1 mol dm-3 Na2SO4 aqueous solution. The anodic photocurrent density at 1.9 V vs. Ag/AgCl was 1.1 mA cm-2 and the flat-band potential of P3TA, estimated from the onset of an anodic photocurrent, was -0.1 V vs. Ag/AgCl. The band gap of P3TA was 2.4 eV, obtained from an hν vs. (hν PC)1/2 plot.
Absorption Spectra of C60-Excited States in Various Solvents: Their Dependence on the Ionization Potential of Solvent Molecules
Authors: Suzuki Isao , Tsuboi Yasuyuki , Miyasaka Hiroshi , Itaya Akira 
Published: September 2002

Abstract
Using a picosecond laser photolysis system, the absorption spectra of excited states of C60 in twelve solvents were measured in the 590—1190 nm wavelength range. The absorption spectra observed immediately after a 532 nm picosecond laser excitation and those in the late-time region depended upon the solvents. In particular, the former dependence was much larger than the latter one. Their spectral shapes did not correlate with either dielectric constant of the solvents or their refractive index, but with their ionization potential (Ip). The early-gated absorption spectra of C60 in solvents with a small Ip were extraordinary broad compared with those in solvents with a large Ip. In addition, the absorption changed to those observed in the late-time region both with a decay time constant of 1.2±0.05 ns and with keeping the isosbestic points. This time constant was the same as the lifetime of the C60-singlet excited state (1C60*) reported previously, and the presence of the isosbestic points was also the same as that observed during spectral evolution from Sn←S1 absorption of C60 to its Tn←T1 one. Combining the results of the resonance Raman spectra by Gallagher et al. with the present ones suggested that the solvent-dependent early-gated absorption spectra of the C60-excited state are ascribed to 1C60* with a distortion induced by specific interactions with solvents molecules through the donation of their π-electron density without forming obviously excited-state complexes. The transient absorption spectra observed immediately after the direct excitation of ground-state charge-transfer complexes formed between C60 and solvent molecules with a small Ip were not due to ionic species, but to 1C60*, suggesting that the photogenerated ionic species undergo a very rapid charge-recombination reaction to result in 1C60* and the ground-state solvent molecule. The absorption spectra in the late-time region, which showed a slight dependence on Ip of the solvent molecules, as aforementioned, were assigned to the Tn←T1 absorption of C60; the dependence was considered to be also ascribed to the same reason as that for 1C60*.
Ethylene Polymerization Catalyzed by Ruthenium and Iron Complexes Containing 2,6-Bis(2-oxazolin-2-yl)pyridine (Pybox) Ligand-Cocatalyst System
Authors: Nomura Kotohiro , Sidokmai Warit , Imanishi Yukio 
Published: September 2002

Abstract
RuX2(ethylene)(pybox) [X = Cl (1), I (2), and CF3SO3 (3); pybox = 2,6-bis[(4S)-4-isopropyl-2-oxazolin-2-yl]pyridine] complexes have exhibited moderate catalytic activity for ethylene homopolymerization and ethylene/1-hexene copolymerization in the presence of MAO. The incorporation of 1-hexene (27.2 mol%) in the resultant copolymer was confirmed by 13C NMR spectrum. The resonances corresponding to the triad sequence of HHH were negligible. A small rE·rH value of 0.32, where rE and rH are the monomer reactivity ratios of ethylene and 1-hexene, respectively, was thus obtained, indicating a significantly alternating tendency. FeCl2(pybox) (4) has also exhibited the activity for ethylene polymerization in the presence of MAO. The attempted copolymerization of ethylene with 1-hexene by 4 gave linear polyethylene without incorporating 1-hexene.
Energy Conversion from Proton Gradient to Electricity Based on Characteristic Redox Behavior of an Aqua Ruthenium Complex with a Quinone Ligand
Authors: Tsuge Kiyoshi , Kurihara Masato , Tanaka Koji 
Published: September 2002

Abstract
A ruthenium aqua complex having a quinone ligand, [Ru(trpy)(dbq)(H2O)](ClO4)2 (trpy = 2,2′:6′,2′′-terpyridine, dbq = 3,5-di-t-butyl-1,2-benzoquinone) ([Ru(q)(H2O)](ClO4)2) was prepared. Its electrochemical properties and electronic absorption spectra were measured in the presence of a base in acetone. The detailed analysis of those measurements revealed that the addition of a base caused not only the deprotonation but also the reduction of [Ru(q)(H2O)]2+. The redox reactions coupled with acid-base reactions were demonstrated from the large difference in redox properties of aqua and hydroxo complexes. Taking advantage of unique redox reactions induced by the acid-base equilibrium between aqua and hydroxo complexes, we have succeeded in constructing the first energy transducer which converts the proton gradient to electricity. A similar ruthenium aqua complex with a bipyridine ligand, [Ru(trpy)(bpy)(H2O)](ClO4)2, also reversibly dissociates a proton of aqua ligand. However, it has no ability to convert the proton gradient to electricity due to the lack of a suitable molecular orbital which can accommodate electrons on the electron-rich hydroxo ligand.
Rubrene Cation Radical Stabilized by Polyiodide Chains in the (Rubrene)I9 Crystal
Authors: Kameya Megumi , Naito Toshio , Inabe Tamotsu 
Published: September 2002

Abstract
A fused polycyclic aromatic compound, rubrene (RB), has been found to form a charge-transfer compound with iodine with the stoichiometry of RB·I9. The crystal is monoclinic, space group C2/c, a = 14.482(4), b = 16.676(8), c = 19.985(4) Å, β = 106.90(2)°, V = 4618(2) Å3, and Z = 4. In this crystal, a unique branched crank-shaped one-dimensional (I9-)∞ polyiodide chain is formed. RB is surrounded by the polyiodide, and its cation radical state, which is unstable under normal conditions, is stabilized. The formation of the RB cation radical has been confirmed by IR, VIS-NIR, and EPR spectroscopies. The magnetic susceptibility measurement has indicated the existence of superexchange interactions through the polyiodide.
Simultaneous Determination of Lanthanoids and Yttrium in Rock Reference Samples by Inductively Coupled Plasma-Mass Spectrometry Coupled with Cation Exchange Pretreatment
Authors: Lee Kyue-Hyung , Oshima Mitsuko , Takayanagi Toshio , Motomizu Shoji 
Published: September 2002

Abstract
The amounts of lanthanoids (Ln) and yttrium (Y) in eleven GSJ (Geological Survey of Japan, Tsukuba) rock reference materials have been determined. Fundamental studies on trace analysis of rock samples by inductively coupled plasma-mass spectrometry (ICP-MS) were conducted to obtain accurate contents of rare earth elements. The samples were dissolved using a conventional acid digestion technique, then treated on a cation exchange column for the removal of matrix components. Isobaric interferences from metal oxide ions were corrected based on the results of the experimentally obtained percentages of the metal oxide formation. A long-term stability test of the ICP-MS instrument with multielement standard solutions proved that all data obtained at concentration ranges from 0.01 to 10 ng ml-1 were reproducible, the drift of signals were less and the relative standard deviation (RSD) was within ±2.5%. The recoveries of Ln and Y from the cation exchange column were found to be (100±4)%. The results obtained for an igneous rock series showed good agreement with the recommended values given by GSJ, and their chondrite-normalized patterns were smooth.
Effect of the Hydrophobic Anion of Picrate on the Extraction of Europium(III) with Diamide
Authors: Naganawa Hirochika , Suzuki Hideya , Tachimori Shoichi , Nasu Akinobu , Sekine Tatsuya 
Published: September 2002

Abstract
The effect of the picrate (pic-) ion on Eu(III) extraction with a diamide (da) from aqueous nitric acid (0.001—0.1 mol dm-3) solutions into benzene was clarified on the basis of the stoichiometry of ion-pair extractions by analyzing the distribution data of Eu(III) and picric acid (Hpic). The extraction of Eu(III) with da was extremely enhanced by adding a hydrophobic anion of pic- to the liquid-liquid system. From analyses of the distribution data of Eu(III) and Hpic, it was concluded that the effect of the hydrophobic anion was caused by the extraction of a single ion-pair of [Eu(da)2](pic)3. The nitrate ion had no relation with the cooperative effect of da and pic-, i.e., the extraction of [Eu(da)2](NO3)3, [Eu(da)2](pic)(NO3)2, and [Eu(da)2](pic)2(NO3) was practically negligible as against the [Eu(da)2](pic)3 extraction. The cooperative effect was reduced by an increase in the aqueous HNO3 concentration, which was induced by a decrease in the pic- concentration in the aqueous phase; the dissociation of Hpic into pic- ion was suppressed by an increase in the H+ concentration, and a part of molecular Hpic was extracted into the organic phase. Furthermore, the extraction of Hpic was also enhanced by an increase in the da concentration in the organic phase, which also induced a decrease in the aqueous pic- concentration. This was found to be due to the formation of a 1 : 1 complex between da and Hpic. However, the extraction of the complexes between da and HNO3 was negligible in the acid concentration range in the present study.
Preparation of Sulfide-Bridged Di- or Trinuclear Pyrrolylimido and Diazoalkane Complexes Derived from a Tungsten Dinitrogen Complex
Authors: Seino Hidetake , Mizobe Yasushi , Hidai Masanobu 
Published: September 2002

Abstract
Tungsten pyrrolylimido and diazoalkane complexes, cis,mer-[WCl2(NNC4H4)(PMe2Ph)3] and cis,mer-[WCl2(NN=CRR′)(PMe2Ph)3], which are readily derived from the dinitrogen complex cis-[W(N2)2(PMe2Ph)4], reacted with [PPh4]2[WS4] to give the sulfide-bridged di- or trinuclear pyrrolylimido and diazoalkane complexes, [PPh4][WCl(NNC4H4)(PMe2Ph)2(μ-S)2WS2] (4) and [PPh4][WCl(NN=CRR′)(PMe2Ph)2(μ-S)2WS2] (R = R′ = Me (5a); R = Me, R′ = Ph; R = H, R′ = p-MeC6H4), or [{WCl(NNC4H4)(PMe2Ph)2(μ-S)2}2W] (7) and [{WCl(NN=CMePh)(PMe2Ph)2(μ-S)2}2W]. Treatment of 4 or 5a with tetraalkylthiuram disulfide resulted in the formation of sulfide-dithiocarbamate complexes: [W(NNC4H4)(PMe2Ph)(S2CNR2)(μ-S)2WS(S2CNR2)] (R = Et, Pri (9b)) and [W(NN=CMe2)(PMe2Ph)(S2CNEt2)(μ-S)2WS(S2CNEt2)]. On the other hand, replacement of two PMe2Ph ligands in 4 and 5 by Ph2PCH2CH2PPh2 (dppe) afforded [PPh4][WCl(NNC4H4)(dppe)(μ-S)2WS2] and [PPh4][WCl(NN=CRR′)(dppe)(μ-S)2WS2] (R = R′ = Me; R = Me, R′ = Ph (12b)), where 12b has been shown to react further with [RhCl(cod)]2 (cod = 1,5-cyclooctadiene) to give a bimetallic trinuclear complex [WCl(NN=CMePh)(dppe)(μ-S)2W(μ-S)2Rh(cod)] (13). Detailed structures have been determined by X-ray analyses for 4, 5a, 7, 9b, and 13.
Photoreduction Processes of α-Dodecamolybdophosphate in Aqueous Solutions: Electrical Conductivity, 31P NMR, and Crystallographic Studies
Authors: Ishikawa Eri , Yamase Toshihiro 
Published: September 2002

Abstract
The photoreduction processes of α-[PMo12O40]3- (α-PMo12(0)) in aqueous solutions at pH 2.0 are discussed on the basis of the results of the electrical conductivities and 31P NMR spectra of photolytes, and the crystal structures of α-type two-electron and β-type four-electron reduction species isolated from photolytes as α-[(iPr)2NH2]4[HPMo12O40]·4H2O (1) (α-PMo12(II)) and β-[(iPr)2NH2]3[H4PMo12O40]·2H2O (2) (β-PMo12(IV)) : (i) A one-electron reduction species produced by the photoredox reaction of α-PMo12(0) with methanol is degraded to α-B-[H3PMo9O31(OH)3]3- (α-B-PMo9(0)) and MoV-containing Mo-triad species (Mo3). (ii) The formation of the α-type mono-protonated two-electron reduction species, α-[HPMo12O40]4- (α-PMo12(II)), results from the isomerization of the β-type two-electron reduction species, β-[PMo12O40]5- (β-PMo12(II)), which is produced by coupling between the one-electron reduced α-B-PMo9 (α-B-PMo9(I)) and Mo3. (iii) The β-type four-protonated four-electron reduction species, β-[H4PMo12O40]3- (β-PMo12(IV)) as a final product is produced by the disproportionation of α-PMo12(II). The change in the electrical conductivity of the photolytes during photolysis supports the above processes for the photoreduction of α-[PMo12O40]3- to β-[H4PMo12O40]3- at pH 2.0.