bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis, Crystal Structure, and Characterization of Layered Aluminum Methylphosphonate
Authors: Maeda Kazuyuki , Hashiguchi Yoshie , Kiyozumi Yoshimichi , Mizukami Fujio 
Published: June 2006

Abstract
The first aluminum methylphosphonate with a layered structure, designated AlMepO-ζ, giving an ideal composition of Al(OH)(O3PCH3)·H2O was synthesized with a hydrothermal procedure. AlMepO-ζ is monoclinic, space group P21/c, with a = 7.8676(7), b = 7.0744(13), c = 9.4789(7), β = 106.599(6)°. The framework in a sheet containing unidimensional [–Al–(OH)–Al–] chain is topologically the same as VO(O3PC6H5)·H2O. Methyl groups protrude into the interlamellar space. TG-DTA and MAS-NMR results revealed the decomposition mechanism.
Total Internal Reflection Fluorometric Study of the Ion-Association Adsorption of Ionic Derivatives of Porphyrin at Liquid–Liquid Interface
Authors: Saitoh Yoriko , Watarai Hitoshi 
Published: June 2006

Abstract
Interfacial ion-association adsorption of 5,10,15,20-tetrakis(4-sulfonatophenyl)-21H,23H-porphine (H2tpps4−) with hexadecyltrimethylammonium ion and 5,10,15,20-tetrakis(1-methyl-4-pyridinio)-21H,23H-porphine (H2tmpyp4+) with 1-hexadecanesulfonate was measured by means of a total internal reflection fluorometry at toluene/water systems. The adsorptivity of the porphyrins was negligibly small in the absence of the ionic surfactants, but it was increased by the addition of the surfactants in the 10−8—10−7 M concentration. The adsorptivity was governed by the positive or negative charge of the surface-active counter ion and its concentration, which determined the electrostatic potential of the interface. Further, it was found that zinc(II)-1,10-phenanthroline, a hydrophobic complex cation, remarkably enhanced the interfacial adsorption of [Zntpps]4− ion, but showed no positive effect on the adsorption of [Zntmpyp]4+ ion.
Kinetics of the Formation and Decay of Benzidine Mono Radical Cation in Aqueous Solution
Authors: Aravindan Ponnu , Maruthamuthu Pichai , Dharmalingam Periasamy 
Published: June 2006

Abstract
The oxidation of benzidine by Ce(IV); the oxoanions MnO4− and Cr2O72−; peroxides, namely potassium peroxomonosulfate (KHSO5), peroxodisulfate (S2O82−) and H2O2; and halogens viz., Cl2, Br2, and I2, to the benzidine mono radical cation (benzidine•+) and further oxidation to the benzidine diradical cation (+•benzidine•+) by the above-mentioned oxidants, except for Br2 and I2, were investigated by a stopped-flow technique. The kinetics of both reactions, the formation and decay of benzidine•+, were monitored by following the absorption of the radical cation at λmax = 603 nm. The reactions were found to follow a total second-order kinetics, first-order each with respect to [benzidine] or [benzidine•+] and the [oxidant]. The effects of the pH and temperature on the formation and decay of benzidine•+ were also investigated. The kinetic and transition-state parameters were evaluated with a suitable reaction mechanism. The radical cation benzidine•+ was converted back to the parent compound, benzidine, by such reducing agents as sulfite (SO32−), thiosulfate (S2O32−), dithionite (S2O42−), and disulfite (S2O52−). The rate constants for these reactions were also estimated. The experimentally determined rate constants for the oxidative electron-transfer reactions were correlated theoretically using Marcus theory; the observed and calculated rate constants show good agreement.
“Syn-Effect” in the Desulfonylation Reaction of α,α-Dialkylated (E)-Allylic Sulfones
Authors: Shibayama Atsushi , Nakamura Tetsuya , Asada Takahiro , Shintani Takehiko , Ukaji Yutaka , Kinoshita Hideki , Inomata Katsuhiko 
Published: June 2006

Abstract
It was found that the desulfonylation reaction of α,α-dialkylated (E)-allylic sulfones with a base preferentially affords the sterically unfavorable (Z)-alkadienes. The relative degree of the “syn-effect”, which is herein defined as an effect which stabilizes the syn-conformation, leading to (Z)-products, in the transition state against the steric hindrance, was revealed for various substituents at the δ-position of the (E)-allylic sulfones to be as follows: RO– &gt;&gt; CH3– &gt; RS– &gt; –CH2– &gt; (CH3)2CH– &gt;&gt; (CH3)3C– &gt; C6H5–. This finding is in accord with a previously found tendency in the conversion of (E)-vinylic sulfones to the corresponding allylic sulfones under basic conditions.
Mechanism for the Production and Reaction of Active-Oxygen Species from Photoexcited Hematoporphyrin Adsorbed on a Biological Heterogeneous System
Authors: Noda Hiroyuki , Ohya-Nishiguchi Hiroaki , Kamada Hitoshi 
Published: June 2006

Abstract
The electronic states of hematoporphyrin (HP) adsorbed on the cell wall of yeast [biological heterogeneous (BH) system] have been characterized based on its fluorescence spectra, in comparison with those of the HP monomer and oligomer in a homogeneous system. The formation of some adsorption structures of HP on a BH system was confirmed from the fluorescence excitation spectra. An ESR method has also been applied to clarify the mechanism for the production and reaction of active-oxygen species from photoexcited HP on a BH system. The hydroxyl radical derived through a three-electron reduction of oxygen was the major product. The mechanism for producing the hydroxyl radical from photoexcited HP on a BH system is discussed as a characteristic feature for the formation of a heterogeneous system containing monomeric HP.
Reactivities of Stable Rotamers. XXXIX. Thermal Decomposition of t-Butyl 3-Methyl-3-(substituted 9-triptycyl)peroxybutanoate Rotamers
Authors: Oki Michinori , Fujino Ichiro , Kawaguchi Daisuke , Chuda Kazumasa , Moritaka Yoko , Yamamoto Yasunori , Tsuda Shingo , Akinaga Tadashi , Aki Michihiko , Kojima Hiroharu , Morita Nobuhiro , Sakurai Makoto , Toyota Shinji , Tanaka Yasuhiro , Tanuma Toshihiro , Yamamto Gaku 
Published: June 2006

Abstract
The ap and sc rotamers of the title compound, where substituents are 1,4-dimethyl, 1,4-dimethoxy, 1,2,3,4-tetrafluoro, and 1,2,3,4-tetrachloro, were thermolyzed in toluene solutions to examine the effects of interactions between the radical center and the substituent. The rates of thermolyses were affected neither by the substituent nor by the rotameric positions, but the product distributions showed dependence on the substituent. In the ap-forms, the effectively bulkier the substituent at the 1-position, the higher the yields of the 5-membered ring compound. This was attributed to the degree of the tilting of the 9-substituent, which forces the radical center to be pushed into the triptycene skeleton. For the sc-forms, the chloro and the methyl substituents exhibited special effects, the former affording a colligation product between benzyl and 2-(1,2,3,4-tetrachloro-9-triptycyl)-2-methylpropyl radicals and the latter showing a tendency of radical migration to the benzylic position. Comparison of the results of thermolyses of the 1,4-dimethyl peroxyester with those of 2(1H)-thioxo-1-pyridyl 3-(1,4-dimethyl-9-triptycyl)-3-methylbutanoate indicates that, although it is believed that these precursors afford the same 2-(1,4-dimethyl-9-triptycyl)-2-methylpropyl radicals, the product distributions were significantly different from each other. These results were attributed to the stabilizing effects of the sulfur compound on the radical in the solvent cage in the latter.
Regioselective Coupling Reaction of Allylic Barium Reagents with Epoxides
Authors: Yasue Katsutaka , Yanagisawa Akira , Yamamoto Hisashi 
Published: June 2006

Abstract
The regioselective coupling reaction of epoxides with allylic barium reagents was achieved. All reactions resulted in high yields with remarkable α-selectivities. 2-Propynylbarium reagent afforded exclusively the corresponding acetylenic alcohol.
First Synthesis and Reactivities of Isolable Dithiiranes and Their 1-Oxides
Authors: Ishii Akihiko , Akazawa Toru , Ding Meng-Xin , Honjo Takanari , Maruta Teruo , Nakamura Shin-ya , Nagaya Hidenori , Ogura Miho , Teramoto Katsuhiko , Shiro Motoo , Hoshino Masamatsu , Nakayama Juzo 
Published: June 2006

Abstract
The reaction of the 6-exo-oxide of 2,2,4,4-tetramethyl-1,5-diphenyl-6,7-dithiabicyclo[3.1.1]heptane (2) with 2KHSO5·KHSO4·K2SO4 gave the first isolable dithiirane oxide, (1RS, 3SR)-3-phenyl-3-(1,1,3,3-tetramethyl-4-oxo-4-phenylbutyl)dithiirane 1-oxide (1), while the 6-endo-oxide of 2 gave both 1 and its (1RS, 3RS)-isomer 10. Under similar reaction conditions, 2 yielded the first isolable, unoxidized dithiirane, 3-phenyl-3-(1,1,3,3-tetramethyl-4-oxo-4-phenylbutyl)dithiirane (3). The dithiirane 3 was also obtained by treatment of 2 with NaOCl–NaClO4. The X-ray structure analyses were performed for 1, 3, and 10. Treatment of unsymmetrical 8,8-dimethyl-1,9-diphenyl-10,11-dithiatricyclo[7.1.1.02,7]undeca-2,4,6-triene with NaOCl–NaClO4gave 3-[1-(o-benzoylphenyl)-1-methylethyl]-3-phenyldithiirane selectively in good yield. However, 1,3-dithietanes, prepared from adamantane-2-thiones, failed to give the corresponding dithiiranes by treatment with 2KHSO5·KHSO4·K2SO4 or NaOCl–NaClO4. The dithiirane 3 thermally isomerized to 2,2,4,4-tetramethyl-1,5-diphenyl-8-oxa-6,7-dithiabicyclo[3.2.1]octane probably via 2,2,4,4-tetramethyl-1,5-diphenyl-5-thioxo-1-pentanone S-sulfide.
NMR Spectroscopy of Cyclodextrin–Inorganic Anion Systems
Authors: Matsui Yoshihisa , Ono Masaharu , Tokunaga Shuichi 
Published: June 2006

Abstract
The addition of alkali salts of chaotropic anions such as Br−, I−, SCN−, N3−, ClO4−, and NO3− to an α-cyclodextrin (α-CD) solution in D2O caused marked downfield shifts in the 1H NMR signal of the C(5)–H located in the interior of the α-CD cavity, whereas the signal showed no or only small upfield shifts upon the addition of alkali salts of antichaotropic anions such as F−, HCO3−, H2PO4−, HPO42−, and SO42−. The effects of the inorganic salts on the chemical shifts (δ) for the other protons of α-CD were significant but smaller than that on δ for C(5)–H. These facts indicate that the chaotropic anions are included within the α-CD cavity and held in the vicinity of C(5)–H. Similar, but smaller, effects of the inorganic salts were observed for β- and γ-CD. The binding constants and thermodynamic parameters determined for complexation of CD’s with some chaotropic anions suggest that hydrophobic and van der Waals interactions, as well as a conformational change of CD macrocycles and the desolvation of CD’s and/or the anions upon complexation, play important roles in complex stabilization. The effect of inorganic salts on the spin-lattice relaxation times of α-CD protons also supports the above conclusion.
A Generalized Fokker–Planck Equation Treatment of Inertia and Non-Markovian Effects on the Short-Time Dynamics of a Collision-Induced Reaction
Authors: Ibuki Kazuyasu , Ueno Masakatsu 
Published: June 2006

Abstract
The inertia and non-Markovian effects on the short-time dynamics of a diffusion-controlled reaction were studied using a generalized Fokker–Planck equation with a boundary condition suitable for a collision-induced reaction. The approximation of half-range Maxwellian velocity distributions was employed to calculate the time-dependent rate constant. At time zero, the rate constant obtained analytically exhibits a limiting value which is independent of the friction kernels, and is smaller than that of the Smoluchowski–Collins–Kimball (SCK) theory. At finite times, the rate constant is obtained numerically, and its initial decay is slower than that of the SCK theory even when only the inertia effect is taken into account. When a non-Markovian effect is also taken into account, the initial slow decay becomes more pronounced. We have also found that the theoretical rate constant is sensitive to the boundary condition for the velocity distribution at the reaction radius. In order to test the results, we carried out a computer simulation of an encounter reaction between a test particle and hard-sphere reactants in a hard-sphere fluid, and obtained the survival probabilities of the test particle. Our results agree excellently with the simulation results.
Phase Separation in Silica Sol–Gel System Containing Poly(ethylene oxide) II. Effects of Molecular Weight and Temperature
Authors: Nakanishi Kazuki , Soga Naohiro 
Published: June 2006

Abstract
Phase separation and gelation behaviors have been studied for acid-catalyzed, alkoxide-based silica systems containing poly(ethylene oxide), PEO. In order to clarify the role of PEO in a phase-separating sol–gel system, the effects of the molecular weight of PEO and the reaction temperature were investigated in detail. The PEO concentration of the highest phase-separation tendency slightly increased along with a decrease in the molecular weight, suggesting that the phase-separation behavior is mainly governed by an interaction between PEO and the solvent mixture. The reaction temperature affected the morphology-composition relationship mainly by its effect on the sol–gel transition kinetics.
Synthesis of New Cationic Schiff Base Complexes of Copper(II) and Their Selective Binding with DNA
Authors: Tanaka Tomohide , Tsurutani Keiko , Komatsu Atsushi , Ito Toyofumi , Iida Kazumi , Fujii Yuki , Nakano Yoshiharu , Usui Yoshiharu , Fukuda Yutaka , Chikira Makoto 
Published: June 2006

Abstract
A series of cationic salen-type Schiff base complexes of copper(II), the general formula of which is [Cu{R3N+–CH2–C6H3(O−)–CH=N–}2X]Br2 (R: CH3, C2H5, C3H7, C4H9; X: C2H4, C3H6, C6H10, C6H4, C10H6), was newly prepared, and the molecular structure of complex 1 (R = CH3, X = C2H4) was determined by an X-ray crystal structure analysis. The binding mode and binding constants (Kb) of all the complexes with calf thymus DNA were investigated at an ionic strength of I = 0.05(NaCl + HEPES buffer, pH = 7.2) using induced CD and the UV-vis spectra. Those complexes with aliphatic X group selectively bound to the groove of DNA, and the Kb’s were in the range of 102—103 mol dm−3 (site size base pairs n = 7.2—7.4). However, those with aromatic X group selectivity intercalated to the base pairs, and the Kb’s were in the range of 104—105mol dm−3 (n = 2.8—4.0). These binding modes were confirmed based on the salt dependence of Kb’s. In addition, 1 and 10 (R = CH3, X = C6H4) were found to exhibit AT-sequence affinity from the induced CD spectra and Kb’s for poly(dA-dT)–poly(dA-dT), poly(dG-dC)–poly(dG-dC), and poly(dA-dC)–poly(dT-dG).
Rapid and Efficient Synthesis of High-Purity Fluorine-18 Labeled Haloperidol and Spiperone via the Nitro Precursor in Combination with a New HPLC Separation Method
Authors: Hashizume Kazunari , Hashimoto Naoto , Miyake Yoshihiro 
Published: June 2006

Abstract
We have completed a convenient synthesis of fluorine-18 labeled butyrophenone neuroleptics from their nitro precursors. Thus, we have developed an efficient single-column HPLC system using a C18-bonded vinyl alcohol copolymer gel (octadecyl polymer, ODP) column and strongly alkaline solvent systems for purifying of the 18F-labeled butyrophenone neuroleptics obtained by a single-step 18F-for-nitro exchange reaction. The method has been applied to the synthesis of two typical butyrophenone neuroleptics ([18F]haloperidol and [18F]spiperone) with high purity in high yield. With information concerning the optimized conditions for the 18F-for-nitro exchange reaction, the synthetic method would be useful for synthesizing various 18F-labeled compounds.
Synthesis of Alkyl[hydrotris(pyrazolyl)borato]ruthenium(II) Complexes by Transmetallation
Authors: Maruyama Yooichiroh , Ikeda Shintaro , Ozawa Fumiyuki 
Published: June 2006

Abstract
The alkylation of [Ru(tp)Cl(cod)] (1) (tp = hydrotris(pyrazolyl)borate) with AlR3 (R = Et, Me) successfully proceeded in a benzene or toluene solution at room temperature to give the corresponding [Ru(tp)R(cod)] complexes (R = Et (2), Me (4)) in high yields (82 and 96%, respectively). On the other hand, the reaction of 1 with an ethylmagnesium compound (Et2Mg or EtMgBr) or EtLi provided a significant amount of [Ru(tp)H(cod)] (3) together with 2.
In Vitro Selection of a DNA Ligand that Selectively Binds to the Anticancer Agent Methotrexate
Authors: Ito Yoshihiro , Suzuki Akinori , Kawazoe Naoki , Imanishi Yukio 
Published: June 2006

Abstract
A DNA ligand that selectively binds to the anticancer agent methotrexate was identified using the in vitro selection method. A pool of single-stranded DNAs consisting of random sequences was incubated with a methotrexate-immobilized agarose gel; bound DNAs were then collected and amplified using the polymerase chain reaction (PCR). This selection process was repeated six times. The selected DNAs were cloned and were found to contain two common sequences. One of these selected DNA clones selectively bound to the methotrexate-immobilized gel and showed a high level of discrimination against the gel immobilized with folic acid, which has a similar chemical structure to methotrexate. In the selection process, a buffer solution was used for DNA binding to the methotrexate-immobilized gel and water was used for elution from the gel. Ultraviolet absorption measurement showed that the conformation of the DNA ligand in the binding buffer was different from that in elution water.
Photoemission Cross Sections for Ions Produced by Collisions of He(23S) Atoms with Linear Triatomic Molecules and Fluorobenzenes
Authors: Tokue Ikuo , Kudo Takeyuki , Kobayashi Masaaki , Yamasaki Katsuyoshi 
Published: June 2006

Abstract
Photoemissions at 200—650 nm resulting from the He(23S) Penning ionization of CO2, CS2, OCS, N2O, C6F6, and C6F5H have been studied in the collision energy range of 120—210 meV using a crossed-beam method. The emission cross sections obtained for the excited parent ions were compared with the values measured at thermal energy. The band strengths for the vibrational bands of the OCS+() system are rather different from the values measured by the photoionization of OCS. The dependences of the emission cross sections for triatomic ions on the collision energy have been compared with those of the partial cross sections for the ion states obtained by Penning ionization electron spectroscopy, and the interaction potentials between He(23S) and the triatomic molecules correlating with the Penning ionization are discussed.
Nonlinear Optical Susceptibility of Oligo- and Polygermanes
Authors: Mochida Kunio , Nagano Shuh-saku , Maeyama Shigeru , Kodaira Takuo , Watanabe Akira , Ito Osamu , Matsuda Minoru 
Published: June 2006

Abstract
Third-order nonlinear susceptibilities (χ(3)) for thin films of oligo- and polygermanes were measured in the range of 0.6—86 × 10−12 esu. A measured χ(3)of 86 × 10−12 esu for a polygermane–polysilane random copolymer, coploy(methylphenylsilylene/methylphenylgermylene), was the largest ever reported for transparent polymers in the visible spectral region.
Efficient Synthesis of Rotaxane Based on Complexation of Acetylene and Dicobalt Hexacarbonyl: Introduction of a Transformable Functional Group
Authors: Tokunaga Yuji , Ohta Go , Yamauchi Yuji , Goda Tatsuhiro , Kawai Nobuhiko , Sugihara Takumichi , Shimomura Youji 
Published: June 2006

Abstract
An efficient end-capping method for preparation of rotaxanes by complexation of dicobalt hexacarbonyl and acetylene moiety of the axle end is described here. The end-capping reaction of pseudorotaxanes proceeds under mild conditions and furnishes the expected rotaxanes bearing a transformable functional group in high yield.
Nickel-catalyzed Conjugate Addition of Arylboron Reagents to α,β-Unsaturated Carbonyl Compounds with the Aid of a Catalytic Amount of an Alkyne
Authors: Shirakawa Eiji , Yasuhara Yuichi , Hayashi Tamio 
Published: June 2006

Abstract
Alkynes in combination with a catalytic amount of a nickel complex were found to catalyze the conjugate addition of arylboron reagents to α,β-unsaturated carbonyl compounds, where use of an optically active alkyne induces the asymmetric addition.
Illumination-induced Magnetization Enhancement of the Weak Ferromagnet [Fe(N3)2(pm)] (pm = Pyrimidine)
Authors: Morishita Yasuhiko , Doi Yoshitaka , Nogami Takashi , Ishida Takayuki 
Published: June 2006

Abstract
The spontaneous magnetization of [Fe(N3)2(pm)] (pm = pyrimidine) was enhanced after UV illumination while the spin-canted antiferromagnetic transition temperature (39 K) was unchanged. Azide-bridged two-dimensional network was damaged on illumination as clarified by IR measurements, possibly leading to an increase of the cant angle.
Dynamical Effect Study of a Stable Trapped Hydrogen Atom by ESR Spectroscopy
Authors: Nakashima Kouichi , Yamauchi Jun 
Published: June 2006

Abstract
Effective spin Hamiltonian parameters of a stable trapped hydrogen atom (H atom) in X-ray-irradiated β-tricalcium phosphate (β-Ca3(PO4)2, β-TCP) were estimated by high frequency ESR (Q-band). The dynamical effect of the H atom was investigated at various temperatures by CW-ESR (X-band) spectroscopy.
Sonoresponsive Volume Phase-transition Behavior of Crosslinked Poly(N-isopropylacrylamide-co-acrylic acid) Microgel
Authors: Huo Dongxia , Kobayashi Takaomi 
Published: June 2006

Abstract
We presented that ultrasound, as a novel environmentally stimuli technique, was used controlling the volume phase-transition temperature of high crosslinked poly(N-isopropylacrylamide-co-acrylic acid) microgels.
Momentum transport processes in the stratiform regions of mesoscale convective systems over the western Pacific warm pool
Authors: Mechem David B. , Chen Shuyi S. , Houze Robert A. 
Published: June 2006

AbstractMomentum transport by the stratiform components of mesoscale convective systems (MCSs) during the Tropical Ocean–Global Atmosphere Coupled Ocean–Atmosphere Response Experiment in December 1992 is investigated using a cloud‐resolving model. The mesoscale momentum transport by the stratiform regions of MCSs is examined in two distinct large‐scale flow regimes associated with the intraseasonal oscillation over the western Pacific warm pool. Model simulations for 14 December 1992 characterize the ‘westerly onset’ period, which has relatively weak low‐level westerlies with easterlies above. Simulations for 23–24 December represent the ‘strong westerly’ regime, when westerlies extend from the upper troposphere to the surface, with a jet 2–3 km above the surface. In the westerly onset simulation, the extensive stratiform region of a MCS contained a broad region of descent that transported easterly momentum associated with the mid‐level easterly jet downward. Thus, the stratiform regions acted as a negative feedback to decrease the large‐scale mean westerly momentum developing at low levels. In the strong westerly regime, the mesoscale downward air motion in the stratiform regions of large MCSs transported westerly momentum downward and thus acted as a positive feedback, strengthening the already strong westerly momentum at low levels. Momentum fluxes by the mesoscale stratiform region downdraughts are shown to have a systematic and measurable impact on the large‐scale momentum budget. Copyright © 2006 Royal Meteorological Society.