bluuebunny/crossref_metadata_2025 huggingface dataset:
Color Change of (E)-2,3-Bis(2,3,4,5,6-Pentafluorophenyl)-3-[2,3,5,6-tetrafluoro-4-(cyanomethyl)phenyl]acrylonitrile by the Addition of Amines
Authors: Nakayama Yasuhide , Inukai Kazuo , Hayashi Koichiro , Irie Masahiro
Published: July 2006

(E)-2,3-Bis(2,3,4,5,6-pentafluorophenyl)-3-[2,3,5,6-tetrafluoro-4-(cyanomethyl)phenyl]acrylonitrile(3E) was synthesized. A benzene solution of 3E turns into a brilliant red color by the addition of aliphatic amines. The coloration mechanism is studied by optical absorption, conductivity and product analyses. It has become apparent that ion-pair formations between 3E and the amines by proton transfer reactions are responsible for the coloration. Structural requirements of the amines for the ion-pair formation are discussed.
Metal Ion Dependent Site Selective Cleavage of P–O–S Linkage in the Methanolysis of Phenyl Phosphatosulfate
Authors: Eiki Toshio , Tagaki Waichiro
Published: July 2006

Effects of various metal ions on the methanolysis of phenyl phosphatosulfate having P–O–S linkage were investigated. Metal ions examined were found to be divided into two different groups in the manner of cleavage of P–O–S linkage: Mg2+, Cr3+, Cu2+, Mn2+, and Ca2+ with larger ionic radii catalyzed the selective P–O bond cleavage, while Be2+, Al3+, Fe2+, and Zn2+ with smaller ionic radii promoted the selective S–O bond cleavage. Such selectivity was discussed in terms of the difference in the mechanisms of P–O and S–O bond cleavage.
Photokilling of Malignant Cells with Ultrafine TiO2 Powder
Authors: Cai Ruxiong , Hashimoto Kazuhito , Itoh Kiminori , Kubota Yoshinobu , Fujishima Akira
Published: July 2006

Photo-irradiated TiO2 particles drive various chemical reactions due to their strong oxidation and reduction ability. This effect is applied in order to kill malignant HeLa cells with TiO2 particles. During 10-min UV irradiation periods, HeLa cells were completely killed in the presence of TiO2 (100 μg cm−3). However, without irradiation these particles showed little cytotoxicity up to 360 μg cm−3. It is concluded that the cells were killed by hydroxyl (OH·) and perhydroxyl (HO2·) radicals produced from water by the irradiated TiO2 particles, and also that the cells were directly oxidized by photogenerated holes in TiO2. The distribution of TiO2 powders in the cells was observed using a transmission electron microscope. The TiO2 powder existed not only on the cell membrane, but also in the cytoplasm. Thus, the cells were damaged by photoexcited TiO2 not only from the cell membrane, but also from the inside of cytoplasm. Finally, the application of this malignant cell photokilling effect to photodynamic therapy is discussed.
Molecular Motion and Phase Changes in Long Chain Solid Normal Alkanes as Studied by 1H and 13C NMR
Authors: Ueda Takahiro , Takeda Sadamu , Nakamura Nobuo , Chihara Hideaki
Published: July 2006

Proton spin-lattice and dipolar relaxation times and 13C CP/MAS NMR spectra were measured on crystalline samples of n-C50H102 and long chain normal alkanes (n-alkanes) with average molecular weight of 595, 1214, and 2305 in order to characterize the static and dynamic molecular structures in the solid state. The 13C CP/MAS spectra indicate that the molecules take all-trans conformation in the orthorhombic unit cell and do not undergo any discernible change on annealing and/or quenching of specimens. On the other hand, the T1d in each material assumes a deep and clear minimum value in the orthorhombic phase; this relaxation process was unambiguously assigned to the molecular uniaxial reorientation about the long chain axis. There is a linear relation between the activation energy and the reciprocal of the chain length. In the case of n-C50H102 a solid state phase transition was found at 351 K. The T1d in the high temperature phase led to extremely high activation energy, 150 kJ mol−1, which may be attributable to molecular self-diffusion or other motion accompanying drastic change in the molecular structure.
Electrochemical Formation of 11-Molybdophosphate Anion at the Nitrobenzene/Water Interface and Its Applicability to the Determination of Orthophosphate Ion
Authors: Osakai Toshiyuki , Himeno Sadayuki , Saito Atsuyoshi
Published: July 2006

Transfer of the hexamolybdate ion, Mo6O192−, at the nitrobenzene(NB)/water(W) interface was studied by ion-transfer voltammetry. The Mo6O192− ion decomposed immediately after being transfered from NB to W. In the presence of orthophosphate ions in the weakly acidic W phase (pH 3.1), molybdophosphate anions, i.e. [H3PMo11O39]4−, were formed at the interface. A well-defined voltammetric wave due to the transfer of complex anions from W to NB was observed; the peak current was proportional to the bulk concentration of orthophosphate ions. Thus, the NB/W interface containing Mo6O192− in NB can function as an ion-selective electrode surface for a voltammetric determination of orthophosphate ions.
Damage of Egg Phosphatidylcholine Liposomes by DNA-Binding Cytotoxic Agents
Authors: O’Connor Charmian J , Denny William A , Emery Diane P , Tank Holger , Sato Toshinori , Sunamoto Junzo
Published: July 2006

The stability of small unilamellar vesicles (SUV) formed by egg phosphatidylcholine has been examined in the presence of four DNA-intercalating drugs—carboxamides of acridine, anthracene, phenylquinoline, and phenylbenzimidazole. The physicochemical stability of the vesicle-membrane changed as the total drug concentration increased and, of the four drugs investigated, the phenylquinolinecarboxamide was the most destructive. The presence of cholesterol in the liposomal bilayer increased resistance to physicochemically induced damage by the drugs except the anthracenecarboxamide. In all cases, coating the liposomes with a polysaccharide made the liposomal surface more hydrophobic and led to the vesicle rupture by the cytotoxic agents. The cytotoxic 9-anilinoacridine derivatives, amsacrine and 9-[2-methoxy-4-(methylsulfonylamino)anilino]-5-methylacridine-4-N-methylcarboxamide (CI-921), were too insoluble to be encapsulated within the aqueous core of liposomes, but the neutral form of CI-921 was intercalated into the liposomal membrane of pullulan-derivative-coated liposomes. In this formulation, CI-921 was more effective against BM 314 carcinoma-cells than the free drug, but an anticarcinoembrionic antigen (anti-CEA) antibody binding liposome provided no additional advantage.
1H NMR Conformational Study of Viologen-Linked Porphyrins (p-FCnV)
Authors: Yamamoto Yasuhiko , Noda Sumio , Nanai Norishige , Okura Ichiro , Inoue Yoshio
Published: July 2006

Conformation of viologen-linked porphyrins (p-PCnV, n=4–7), which are capable of intramolecular electron transfer, was studied by 1H NMR in order to gain insight into the relative geometry of the donor and acceptor during the electron transfer process. The orientation of the viologen with respect to the porphyrin was interpreted in terms of the rate of the intramolecular electron transfer between the two π-systems.
New Chiral Auxiliary; 4,5-Diphenyl-1-methyl-2-imidazolidinone. Its Utility in Highly Enantioselective Aldol Reaction
Authors: Sankhavasi Wongsiri , Yamamoto Makoto , Kohmoto Shigeo , Yamada Kazutoshi
Published: July 2006

The aldol reaction of the boron enolate bearing the titled chiral auxiliary proceeded with high face selectivity.
Oxidation by Cobalt(III) Acetate. Part 13. Oxidation of Substituted Phenols with Cobalt(III) Acetate in Acetic Acid
Authors: Hirano Masao , Ishii Tadamichi , Morimoto Takashi
Published: July 2006

The oxidation of 2,6-di- and 2,4,6-tri-substituted phenols with cobalt(III) acetate has been investigated in acetic acid under an inert atmosphere; the former gave the corresponding diphenoquinones in excellent yields, and the latter yielded side-chain or nuclear acetoxylated products in moderate to good yields.
Electron Spin Resonance Study of Intrinsic Paramagnetism of Soluble Polyaniline Perchlorates
Authors: Iida Masaki , Asaji Tetsuo , Inoue Motomichi , Grualva Heriberto , Inoue Michiko B , Nakamura Daiyu
Published: July 2006

An ESR study was carried out on two polyaniline perchlorates prepared by different chemical methods: Soluble perchlorate I prepared by the use of copper(II) perchlorate as an oxidative coupling agent, and perchlorate II (corresponding to polyemeraldine perchlorate) obtained by treating a polymer base with perchloric acid. The ESR signal intensity of perchlorate I shows a thermally activated temperature dependence at temperatures between 95 and 300 K. The ESR signal intensity of perchlorate II was temperature-independent. When this polymer adsorbed oxygen, the ESR signal showed a thermally activated paramagnetism resembling that of perchlorate I. These paramagnetic properties can be explained by polaron spins that are antiferromagnetically coupled with each other, and are different from the Pauli-type paramagnetism. This suggests that the charge-transport cannot be explained by the migration of paramagnetic polarons along a polymer chain alone.
Reproduction of Bifurcation Structure of Belousov–Zhabotinskii Reaction in Flow System by Oscillatory Flow Term Oregonator
Authors: Sakanoue Shinji , Murase Chiaki , Endo Mitsuo
Published: July 2006

Simulation has been made on the oscillatory flow term Oregonator model (OFO) proposed in our previous paper for the Belousov–Zhabotinskii reaction (BZ reaction) accompanying constant feed. When the amplitude of the forced oscillation term in OFO is taken extremely small, the computational simulation with this model finely reproduces the oscillatory mode, many types of wave patterns including nonperiodic chaotic behaviors and the bifurcation structure, which appear in the experimental results of the BZ reaction in flow system.
Unusual EPR Profile Obtained by Laser Photoreaction of Cardiovascular Tissue
Authors: Nakagawa Kouichi
Published: July 2006

Using spin trap methods, laser generated free radicals from cardiovascular tissue in high viscosity blood solution have been studied by EPR. The EPR spectra obtained are compared with spectra of free radicals produced by both cw and pulsed excimer laser irradiation. Nitroxide spin adduts produced by excimer laser irradiation show an unusual EPR hyperfine structure. In addition, the EPR spectra obtained by continuous wave (cw) laser irradiation are different from those obtained by excimer laser irradiation. The observed β-hydrogen hyperfine coupling for pulsed laser is approximately 1 Gauss smaller than those for cw laser irradiation. The present EPR results provide firm evidence that different free radical reaction intermediates are produced for each laser mode.
Insulator-to-Metal-to-Semiconductor Transitions of One-Dimensional Bis(1,2-dione dioximato)Pt(II) Complexes at High Pressures
Authors: Shirotani Ichimin , Kawamura Akira , Suzuki Kazunaga , Utsumi Wataru , Yagi Takehiko
Published: July 2006

The electrical resistivities and absorption spectra of one-dimensional bis(1,2-dione dioximato)Pt(II) have been studied at high pressures. The resistivities of needle crystals of Pt(dmg)2 and Pt(bqd)2 were measured in detail under a quasi-hydrostatic pressure of up to 7 GPa. Pt(dmg)2 is an insulator with a resistivity of 1015 Ω cm, and Pt(bqd)2 is a semiconductor with 103 Ω cm at atmospheric pressure. A pressure-induced insulator (semiconductor)-to-metal transition was observed for both complexes. This transition arises from a crossing of the 5dz2 valence and 6pz conduction bands. When the pressure was further increasued, a metal-to-semiconductor transition took place at around the pressure that showed a resistivity minimum. A new pressure-induced absorption band was found in the visible region for the Pt complexes. The new band did not shift with pressure; the intensity of the band, however, increased with pressure over a narrow pressure region. The pressure-induced band may be due to intramolecular d–d transitions. The metal-to-semiconductor transition may arise from a change in the electronic states at high pressure, since no anomaly in the strucutre was observed.
Intercalation of a Triethylenetetramine-Substituted Cyclodextrin by Co(II)- and Ni(II)-Montmorillonites
Authors: Kijima Tsuyoshi , Nakazawa Hiromoto , Takenouchi Satoshi
Published: July 2006

The intercalation of mono[6-[(8-amino-3,6-diazaoctyl)amino]-6-deoxy]-β-cyclodextrin (CDtrien) by Co(II)- and Ni(II)-montmorillonites was examined at 25°C. At low uptakes, the CDtrien molecules in both minerals form a monolayer, 13–14 Å thick, with their cavity axes perpendicular to the silicate layers. At higher loadings, guest molecules with the same orientation form a bilayer in Co(21.8 Å thick) and Ni-montmorillonites (17.6 Å). Their thicknesses are larger than those for the Cu-and Zn-analogues, 16.1 Å, i.e. twice the molecular thickness.
Syntheses and Properties of Binuclear Manganese(III) and Manganese(IV) Complexes with 1,2,3,4-Tetrakis(salicylideneamino)-2,3-diphenylbutane
Authors: Nakamura Masaaki , Shimokawa Sayuri , Miyanaka Yuri , Huang Hu , Kai Fumiaki
Published: July 2006

A new dichlorodimanganese(III) and novel tetrachlorodimanganese(IV) complexes with 1,2,3,4-tetrakis(salicylideneamino)-2,3-diphenylbutane were prepared and characterized. The obtained dimanganese(IV) complex was rather stable to moisture in the solid state, but readily reduced to the corresponding dimanganese(III) complex in a methanol solution. The complexes can not be electrochemically formed as mixed valence states.
Structural and Compositional Changes of Hydrated Sodium Molybdenum Bronze by Heat Treatments in Air
Authors: Sotani Noriyuki , Eda Kazuo , Furusawa Kouichi , Hatayama Fumikazu , Takagi Sadao
Published: July 2006

When hydrated sodium molybdenum bronze, VD, was heated in air, dehydration as well as both irreversible and reversible phase changes took place as follows:

Na0.22(H2O)0.43H0.03MoO3.11\xrightarrow442 KNa0.21H0.03MoO3.14\xrightarrow555 KNa2Mo4O13+MoO3\xrightarrow801 Kmelt.
Structure and Polarized Spectra of cis-difluorotetraamminecobalt(III) Perchlorate, cis-[CoF2(NH3)4]ClO4
Authors: Mitsutsuka Yoshihiro , Aoyama Tomonori , Ohba Shigeru , Saito Yoshihiko , Kaneuchi Fumiko , Tsuboi Masamichi
Published: July 2006

The structure of cis-[CoF2(NH3)4]ClO4 has been determined by a single-crystal X-ray diffraction method. Crystals are tetragonal, space group P41 (or P43), a=7.2645(6), c=16.260(2) Å, V=858.1(2) Å3, Z=4,T=297(1) K, final R=0.052 for 970 observed unique reflections. The coordinated F and N atoms could be distinguished unambiguously from each other based on the thermal parameters. The bond distances Co–F and Co–N are 1.828(6)–1.870(5) and 1.924(7)–1.944(7) Å, respectively. The absorption spectra of the single crystals have been examined in the visible and infrared regions with polarized radiation by the use of microspectrophotometers. The 584 nm band (B1) was considered to borrow intensity from some A1 bands through vibronic coupling with some B1 vibrations, and the 504 nm band (A2 & B2) through some A2 and B2 vibrations. Two of the four ammine groups of this cobalt complex were found to give an NH3 rocking frequency (860 cm−1) higher by 50 cm−1 than the other two (at 810 cm−1). This fact has been attributed to two inter-molecular hydrogen bonds (NH···F=2.85–2.68 Å) in which the former two ammine groups are involved.
Monolayer Level Depth Profiling by Laser Induced Fluorescence Spectroscopy
Authors: Wu Xing-Zheng , Kitamori Takehiko , Teramae Norio , Sawada Tsuguo
Published: July 2006

Application limits of the proposed concentration depth profile using laser induced fluorescence spectroscopy based on the reciprocal principle (Bull. Chem. Soc. Jpn., 64, 755 (1991)) were investigated. Although this method has no limitations regarding film thickness and spatial resolution in the depth direction theoretically, for practical applications, they are limited by the instrumental factors. Effects of uncertainty in the observation angle measurement, which depends on the size of the detector, the mechanical precision of the rotating stage, and experimental errors in the fluorescence intensity measurement on the accuracy of the reconstructed concentration depth profile were discussed in detail. The theoretical results predicted nanometer level depth profiling with our laboratory-constructed instruments. A 29 nm thick model film sample, consisting of long chain molecular bilayers, was used to verify the theoretical analysis results. The concentration depth profile for bilayer level steps of about 5 nm was obtained under our experimental conditions. Possible improvements in this method and monolayer level depth profiling were also considered.
Spectrophotometric Determination of Tetrathionate by Its Oxidation with Iodate
Authors: Koh Tomozo , Yajima Masako
Published: July 2006

The conditions under which tetrathionate is oxidized stoichiometrically to sulfate by iodate have been established by investigating the reaction rate of tetrathionate with iodate in a medium containing varying amounts of sulfuric acid at room temperature and 40 °C. Tetrathionate reacted with iodate with a tetrathionate: iodate mole ratio of 3 : 7 under the conditions of the usual procedure. After a complete reaction, the iodine, formed from excess iodate by the addition of iodide, was spectrophotometrically measured as triiodide. A 14-fold chemical amplification was achieved for the determination of tetrathionate by using the proposed method, compared with the conventional methods via the sulfitolysis and cyanolysis of tetrathionate. A linear calibration graph with a negative slope was obtained over the concentration range 2.5×10−7–2.5×10−5 mol dm−3 tetrathionate (0.5–56 μg of S4O62− in 10 cm3); the relative standard deviation was 0.42% at the 1.5×10−5 mol dm−3 tetrathionate level.
Kinetics and Mechanisms of Photo-Induced Reduction of Iodine by Diamine-N-polycarboxylate Ions in an Aqueous Solution
Authors: Kimura Masaru , Ohomura Akiko , Nakazawa Fumiko , Tsukahara Keiichi
Published: July 2006

Although the reduction of iodine by diamine-N-polycarboxylate ions such as ethylenediaminetetraacetic acid, trans-1,2-cyclohexanediaminetetraacetic acid, N-(2-hydroxyethyl)ethylenediamine-N,N′,N′-triacetic acid, and ethylenediamine-N,N′-diacetic acid was negligible in the dark, it occurred greatly upon irradiation with visible light of an aqueous solution over the pH range 4–8. The rate of the photo-sensitized reaction was of half-order regarding both the light intensity irradiated and the concentrations of iodine, which correspond to those of the triiodide ion in the presence of excess iodide ions, and was proportional to the concentration of the diamine-N-polycarboxylate ion. Further, the rate was of half-order for concentrations of I− below 3×10−4 mol dm−3 and was of inversely half-order for concentrations of I− above 6×10−4 mol dm−3. The reaction was inhibited by radical scavengers of acrylonitrile, acrylamide, and hexaamminecobalt(III) ions. Both hydrogen ion and complex forming metal ions, such as copper(II) and zinc(II), are also strong inhibitors of the reaction. The reaction mechanism, where initiation reaction is a photo-dissociation of iodine and the reactive species is a I2\divdot radical anion, is proposed to account for the obtained results.
Selective Ring-Opening Reaction of Epoxides with Sodium Borohydride in the Presence of Cyclodextrins in Aqueous Media
Authors: Hu Ying , Uno Mitsunari , Harada Akira , Takahashi Shigetoshi
Published: July 2006

In the presence of cyclodextrins (CDs), the ring-opening reaction of styrene oxide with NaBH4 in aqueous media proceeded smoothly to give 1-phenylethanol with high selectivity of up to 94%, and kinetic resolution of the racemic epoxide was observed. Kinetic studies suggest the resolution based on the different reaction rates between two enantiomers included in the CD’s cavity. The reaction of epoxides such as 1,2-epoxyindan and 1,2-epoxy-3-phenylpropane are also affected by the addition of CDs to proceed smoothly with high regioselectivities.
Prediction of Product-Selectivity in an Electroorganic Process by Mathematical Modeling of Reaction Mechanism. A Rotating Cylinder Electrode System
Authors: Cheng Po-Chung , Nonaka Tsutomu , Chou Tse-Chuan
Published: July 2006

A mathematical mechanism model is developed for the electroreduction of carbonyl compounds in an acidic solution and shows that the formation ratio of hydrodimeric to hydromonomeric products, i.e. the product-selectivity, depends on substrate concentration, mass transfer coefficient and current density. Model calculations are in agreement with experimental results from the electroreduction of p-methylbenzaldehyde using a rotating cylinder cathode and explain a drastic effect of mass transport on the product-selectivity.
A Comparative Study on the Acidic Properties and Catalytic Activities of TiO2, SiO2, Al2O3, SiO2–Al2O3, SiO2–TiO2, Al2O3–TiO2, and TiO2–SiO2–Al2O3
Authors: Sabu Kuzhunellil Raghavan Pillai , Rao Kalur Vijayachandra C , Nair Chandrathil Govindan Ramachandran
Published: July 2006

Investigations are carried out to have a systematic comparison of the acidic properties and catalytic activities of single oxide TiO2, SiO2, Al2O3, their binary oxides and the ternary oxide TiO2–SiO2–Al2O3. The acidity distributions are measured by using butylamine titration technique and the test reactions selected for the catalytic activity measurements are alkylation of toluene with 2-propanol and the dehydration of 2-propanol. The single oxides have only low acid strength and are not at all active in catalyzing the alkylation reaction, but are marginally active in the dehydration of 2-propanol. However the binary oxides SiO2–TiO2 and Al2O3–TiO2 of 10% by weight of TiO2 are found to contain very strong acid sites Ho≤−8.2 and are highly active catalysts in both the test reactions. But TiO2–SiO2–Al2O3 of 10% by weight of TiO2 showed the highest acid amount and the highest activity in the aikylation and dehydration reactions compared to the binary oxides. The acid amount and the catalytic activity of the ternary oxide increased with the increase of TiO2 content upto 50 mol% of TiO2 and then decreased. The ternary oxide containing 80 mol% of TiO2 is rich in weak acid sites. The increase of TiO2 content does not affect the selectivity.
Dynamics of Autoxidation of Aqueous Sulfur Dioxide in Aqueous Suspensions of Cadmium Oxide
Authors: Rani Ashu , Prasad D S N , Bhargava Rachna , Gupta Krishna Swarup
Published: July 2006

Autoxidation of S(IV), in buffered solutions,conforms the rate law (1). The increase in buffer concentration has a

R obsd=k5[CdO][S(IV)]2[H+]−1.22 (1)

rate decreasing effect. On the other hand, in unbuffered solutions the kinetics obey a different rate law (2).

R obsd=(k10+k11[CdO])[S(IV)][H+]−0.5 (2)

In both situations, the dissolution of CdO accompanies the autoxidation. A heterogeneous catalytic mechanism involving adsorption of both dioxygen and sulfur(IV) on the surface of CdO particle has been proposed.
Aryliminodimagnesium Reagents. XIX. Effects of Miscellaneous Metal Halides on Oxidative Self-Coupling of the Reagent, and on Its Condensation with Nitrobenzene. A New Preparative Route to o,o′-Dihydroxyazobenzene
Authors: Okubo Masao , Shiku Haruko
Published: July 2006

Fourteen metal halides (MXn) were each added to the solutions of aryliminodimagnesium (p-RC6H4N(MgBr)2, IDMg) in tetrahydrofuran, and the effect of MXn on relative yields of products was examined in the following three IDMg reactions: (A) oxidative coupling leading to symmetrical azobenzene, (B) condensation with nitrobenzene, and (C) condensation with o-hydroxy-substituted (o-HO) nitrobenzene. Reaction A was promoted by addition of CuCl2, and the yield of azoxybenzenes in reaction B was improved by addition of NiCl2 or CdCl2. Reaction C was similarly modified by addition of CdCl2 so as to improve the yield of o-HO-azoxybenzenes. Their acetyl derivatives underwent a facile photoinduced migration of azoxy oxygen and were successively hydrolyzed to afford bidentate chelating agents, o,o′-(HO)2-azobenzenes.
Complexations of New Pyridylazo Ligands with Ni(II), Zn(II), and Cd(II)
Authors: Huang Hu , Kai Fumiaki , Uragami Chiemi , Hirohata Masaaki , Chikushi Hiroaki , Yanaka Hisae , Honda Mayumi , Nakamura Masaaki
Published: July 2006

New ligands, 1-(3,5-dichloro-2-pyridyl-azo)-2-naphthol, 2-(3,5-dichloro-2-pyridyl-azo)-5-(dimethylamino) phenol, and 2-(3,5-dichloro-2-pyridyl-azo)-5-(dimethylamino)benzoic acid, were synthesized. Changes in the reduction potentials and electronic spectra of the ligands upon complexation with Ni(II), Zn(II), and Cd(II) were studied. The dissociation constants of the ligands and the stability constants of their metal(II) complexes are discussed.
Synthesis of 2,2,2-Trifluoroethylated Onium Salts of Nitrogen, Sulfur, and Phosphorus with (2,2,2-Trifluoroethyl)phenyliodonium Triflate
Authors: Umemoto Teruo , Gotoh Yoshihiko
Published: July 2006

Various 2,2,2-trifluoroethyl onium triflates were synthesized by treating tertiary amines, pyridines, quinoline, a triazole, sulfides, and a phosphine with (2,2,2-trifluoroethyl)phenyliodonium triflate. Sulfoxides and N-oxide were converted to the corresponding trifluoroethylated salts. As an application, CsF-treatment of (2,2,2-trifluoethyl)triphenylphosphonium triflate with an aldehyde was shown to produce a trifluoromethylated olefin.
Efficient Transformation of Methyl Propargyl Ethers into α,β-Unsaturated Ketones
Authors: Fukuda Yukitoshi , Utimoto Kiitiro
Published: July 2006

Methyl propargyl ethers, obtained from carbonyl compounds by successive treatment with an acetylide and MeI, were easily converted to the corresponding α,β-unsaturated ketone by regioselective hydration of acetylenic moiety followed by elimination of methanol under the catalytic action of Au(III).
Preparation and Crystal Data of the New Compounds Ag7MS6 (M=Ta and Nb)
Authors: Wada Hiroaki
Published: July 2006

The compounds Ag7TaS6 and Ag7NbS6 were prepared by a sealed silica tube method at 500°C for 4 d. They crystallize in the face-centered cubic system with the unit-cell dimensions of a=10.5139±0.0003 Å and a=10.5001±0.0006 Å, respectively. From the density measurements, it has been clarified that the unit cell contains four formula units.
Equilibrium and Kinetic Studies on Complex Formation Reaction between Crown Ethers and Bivalent Transition Metal Ions
Authors: Matsuyama Hideto , Arimura Takeo , Miyake Yoshikazu , Teramoto Masaaki
Published: July 2006

The complex formation reaction between crown ethers and bivalent transition metal ions was investigated. Although the obtained equilibrium constants were generally small, there was a case where the constant was larger than that for the crown ether–alkali metal system. From kinetic studies the reactions were found to obey the Eigen’s mechanism.
Synthesis and Reactions of Some New Pyridazinones
Authors: Ghani Essam Abdel
Published: July 2006

3-(p-Ethoxybenzoyl)acrylic acid (1) reacts with 3-methyl-1-phenyl-2-pyrazolin-5-one to give an addition compound 2. The condensation of 2 with hydrazine hydrate affords 4,5-dihydro-3(2H)-pyridazinone (3a). Reaction of 3a with dimethyl sulfate, diethyl sulfate, ethyl bromoacetate, POCl3, and P2S5 gave the N-substituted pyridazinones 3b–d, a dichloro derivative 5a, and a dithione 7. The behavior of the dichloro and the dithione derivatives was studied toward different reagents. The in vitro antibacterial screening reveals moderate activity against Gram-positive for compounds 3a and 3c while 4 and 7 are inactive.
Preparation and Properties of Heteropoly Molybdovanadate(V) Complexes
Authors: Himeno Sadayuki , Osakai Toshiyuki , Saito Atsuyoshi
Published: July 2006

Tetrabutylammonium salts of the mixed heteropoly molybdovanadate(V) anions, [Hx−1V(VxMo12−x)O40]4− (x=1–3) were prepared from a Mo(VI)–V(V)–CH3CN system at room temperature. These mixed heteropoly anions were distinguished by their voltammetric behavior; the anions with x=1, 2, and 3 were electroreduced by one-, two-, and three-electrons due to the peripheral V atoms at a glassy carbon electrode. The spectroscopic properties were also reported. Their formation conditions were compared with those of 12-molybdovanadate (V), [VMo12O40]3−, especially regarding the concentrations of Mo(VI), V(V), acid, and organic solvents, the nature of organic solvents, and the ionic strength of the system. It should be emphasized that the 12-molybdovanadate(V) and mixed molybdovanadate(V) complexes are not formed in the absence of organic solvents.
Crystal Structure of the Organic Metal (DMET)2BF4 with Two Columns along Two Crystallographic Axes
Authors: Ishikawa Yoshimitsu , Saito Kazuya , Kikuchi Koichi , Kobayashi Keiji , Ikemoto Isao
Published: July 2006

The crystal structure of (DMET)2BF4: 5,6-dihydro-2-(4,5-dimethyl-1,3-diselenol-2-ylidene)dithiolo[4,5-b] [1,4]dithiinium tetrafluoroborate (2:1), (C10H10S4Se2)2BF4, is determined. Crystal data: Mr=919.49, triclinic, P\bar1, a=7.032(2), b=7.812(3), c=27.502(11) Å, α=90.87(2), β=90.28(2), γ=106.22(2)°, V=1450.5(15) Å3, Z=2, Dx=2.11 Mg m−3, λ(Mo Kα)=0.71068 Å, μ=5.60 mm−1, F(000)=890, T=297 K, R=0.077 for 4600 reflections. Two crystallographically independent DMET molecules separately form columns along nearly perpendicular directions, and ordered BF4 anions are located between the DMET columns.
Benzo[b]cyclohept[e][1,4]oxazines IV. Synthesis and Properties of All Possible Benzoxazinotropones
Authors: Wakabayashi Hidetsugu , Kurihara Teruo , Ishikawa Sumio , Okada Joji , Nozoe Tetsuo
Published: July 2006

Five isomeric benzo[b]cyclohept[e][1,4]oxazin-6∼10-ones (hereafter refered to as benzoxazinotropones) and bromobenzoxazinotropones were prepared almost quantitatively by the hydrolysis of the corresponding mono-, di-, and tribromobenzo[b]cyclohept[e][1,4]oxazines with refluxing acetic acid. On the basis of spectral data and theoretical calculations, benzo[b]cyclohept[e][1,4]oxazin-6∼9(11H)-ones are believed to exist in the keto form. These compounds gave respective methoxy- and acetoxybenzo[b]cyclohept[e][1,4]oxazines when reacted with diazomethane and acetic anhydride. On the other hand, benzo[b]cyclohept[e][1,4]oxazin-10(11H)-one was found to exist in a stable, intermolecularly hydrogen-bonded form and did not form acetoxylated or methylated compounds. Possible reaction pathways for the formation of these products are discussed.
Behavior of the Excited Cis Singlet State of a One-Way Isomerizing Olefin. Further Insight into Potential Energy Surfaces of 1-(3,3-Dimethyl-1-butenyl)pyrene
Authors: Okamoto Hiroaki , Arai Tatsuo , Sakuragi Hirochika , Tokumaru Katsumi , Kawanishi Yuji
Published: July 2006

The decay processes of the excited singlet state and potential energy surfaces of 1-(3,3-dimethyl-1-butenyl)pyrene (BP) were investigated. A long-lived fluorescence from the cis isomer and involvement of a quantum chain process for one-way isomerization suggest that the isomerization on direct excitation proceeds in the triplet manifold after intersystem crossing at the cis conformation.
Structural Transition Behavior of Potassium Salts of Saturated Fatty Acids, CH3(CH2)nCO2K (n=14, 16, 18, 20)
Authors: Ishioka Tsutomu
Published: July 2006

The structural transition behavior of potassium soaps (99% purity), CH3(CH2)nCO2K (n=14, 16, 18, 20), having low water contents of less than 10 wt% was investigated by both DSC and vibrational spectroscopies. Nine phases from crystal (I<80°C) to liquid crystal (260°C<IX) were observed for n=14 and 16 by thermal measurements. An additional phase I′ (I<I′<II) was found for n=18 and 20. The structural changes of the alkyl chains accompanied by these transitions were investigated by using IR and Raman methods. With increase in temperature, the itensities of the IR methylene progressive bands which were characteristic of all-trans conformation decreased and conformational defect bands ascribed to gt-, gg-, and gtg′ conformations, were observed in phases I′, II, and III for n=14–20. These indicate the onset of a partial melting of the chains in these phases. At the transition from phase III to IV, the chains entered liquid-like conformations. The result was also confirmed by the Raman spectra.
Solvent Polarity Parameters of Supercritical Carbon Dioxide as Measured by Infrared Spectroscopy
Authors: Ikushima Yutaka , Saito Norio , Arai Masahiko , Arai Kunio
Published: July 2006

The solvent polarity parameters of supercritical carbon dioxide were determined as a function of the temperature and pressure within the ranges 318–353 K and 5.85–28.5 MPa. An infrared (IR) spectroscopic technique has been employed to determine the values of π* dipolarity/polarizability and the Lewis basicity parameter BMeOD by measuring the transitions in the IR absorption wavelength of functional groups (such as C=O and O–H···BA, where BA is a hydrogen-bond acceptor), in supercritical carbon dioxide. Ultraviolet/visible (UV/vis) spectroscopy was used to determine the value of the Kamlet-Taft’s solvatochromic acidity partameter, α. The BMeOD-value was enhanced with density, but was very small at the temperatures and pressures examined, almost the same as that for hexane. The α-value tended to be dependent on density at lower pressures, but was remarkably smaller compared with those for alcohols. The π*-value significantly increased with an increase in the density, becoming more negative at higher temperatures above 10 MPa. Furthermore, the ET(30)-value was estimated by using the determined π*-value. A reliable ET(30)-value for supercritical carbon dioxide has been obtained.
Selective Isomerization of 1,5-Cyclooctadiene to 1,4-Cyclooctadiene Catalyzed by Bis(acetylacetonato)nickel–Triethyldialuminum Trichloride–Phosphorus Ligand
Authors: Sakakibara Yasumasa , Yamamoto Isao , Sasaki Ken , Sakai Mutsuji , Uchino Norito
Published: July 2006

The isomerization of 1,5-cyclooctadiene (1,5-COD) with Ni(acac)2–Et3Al2Cl3–phosphorus ligand (Ni : Al2 : P=1 : 10 : 3) was first examined with varying P ligands in toluene in order to find suitable conditions for the formation of 1,4-COD. The product distribution depended largely on the P ligands. For several phosphites possessing very strong π-acceptor properties, the main product was 1,4-COD. In particular, the less-bulky bicyclic phosphite, 4-ethyl-2,6,7-trioxa-1-phosphabicyclo[2.2.2]octane (L-3) was very effective and gave 1,4-COD in a high selectivity of 93% at 66% conversion (1,5-COD/ Ni=500, molar ratio) by employing a low temperature of −30°C. However, the reaction stopped before reaching completion because the catalyst was deactivated by the accumulation of 1,4-COD product. The conversion, depending on the 1,5-COD/toluene ratio (volume) rather than the 1,5-COD/Ni ratio, increased with a decrease in the 1,5-COD/ toluene ratio and was 66–69% at a ratio of 0.19. On the other hand, the catalyst (P: L-3) was much less active for 1,4-COD than for 1,5-COD and was deactivated quickly under the same reaction conditions. This appeared to result in a high selectivity of 1,4-COD in the isomerization of 1,5-COD. The mechanistic implications of the experimental results are discussed.
Ortho Lithiation of 2-Hydroxymethyl-1,4,5,6,8-pentamethoxynaphthalene, a Supplement
Authors: Tanoue Yasuhiro , Terada Akira
Published: July 2006

The structures of the products in our previous report “One-Pot Ortho Hydroxylations of 2-(1-Hydroxyalkyl)-naphthalenes and (1-Hydroxyalkyl)benzenes” were reexamined by 13CNMR spectra and part of our previous interpretation will be corrected here. The lithiations of 2-(1-hydroxyalkyl)-1,4,5,6,8-pentamethoxynaphthalenes occurred at the 7-position, and not at the 3-position as we reported.
Vinyl Polymers Bearing a Pyrrole Ring. II. 5,10,15,20-Tetraphenylporphyrins with a Substituent-Bearing Vinyl Group at the Pyrrole Residue and Their Zinc Complexes
Authors: Kamogawa Hiroyoshi , Nakata Takuharu , Komatsu Sei
Published: July 2006

5,10,15,20-Tetraphenylporphyrins (Por) with a styrenic double bond-bearing substituent attached at the pyrrole residue with an amide or ester spacer were synthesized starting with 3-substituted pyrroles. Free radical copolymerization of ZnPor, prepared from Por, with 1-vinyl-2-pyrrolidone gave more favorable results than did Por.
X-Ray Crystallographic Analysis of Methyl (1S,2R,5R,6S,7R)-5,6-Dimethyl-2-(ω-camphanoyloxy)bicyclo[4.3.0]nonane-7-carboxylate. Revision of the Absolute Configurations of the Liverwort Sesquiterpenoids (−)-Chiloscyphone and (+)-Chiloscypholone
Authors: Tori Motoo , Hasebe Takeshi , Asakawa Yoshinori , Ogawa Keiichiro , Yoshimura Shin
Published: July 2006

The X-ray analysis of the title compound has been carried out to give unambiguous assignment of the absolute configurations of the liverwort sesquiterpenoids (−)-chiloscyphone and (+)-chiloscypholone, each for which the enantiomerically opposite configurations had been assigned in the previous report.
Reductive Deacetoxylation of Allylic Acetates Using Hexacarbonylmolybdenum(0)
Authors: Masuyama Yoshiro , Maekawa Kazunobu , Kurihara Toshiyuki , Kurusu Yasuhiko
Published: July 2006

Aliphatic allylic acetates were reduced to alkenes with hexacarbonylmolybdenum(0) in refluxing dioxane under nitrogen atmosphere. These reactions were accelerated by the addition of H2O. 1-Aryl- or 3-arylallyl acetates caused deacetoxylative allylic homocoupling under the same conditions.
Luminescence and Circularly Polarized Luminescence of Mononuclear and Binuclear Chromium(III) l-Alaninato Complexes
Authors: Tsubomura Taro , Ohkouchi Iwao , Morita Makoto
Published: July 2006

Luminescence and circularly polarized luminescence (CPL) spectra were investigated at low temperatures in order to clarify the chiroptical and electronic structures of monomeric and dimeric chromium(III) alaninato complexes. In the monomeric complexes, [Cr(l-(or d-)ala)3]·H2O, R1 and R2 lines of opposite spectral signs were found in the CPL spectra. The signs and relative intensities of the peaks were found to be comparable with circular dichroism (CD) spectra by employing theoretical arguments based on a strong crystal field theory. In the case of hydroxo-bridged dimeric complexes, [Cr2(OH)2(l-(or d-)ala)4]·3H2O, although the luminescence spectra of exchange-coupled pair states were clearly observed with a deduction of reasonable exchange interaction parameters, the CPL spectral components were not discernible because of the meso-type structure.
Effect of ZnO Addition on Cobalt–Alumina Interaction Species
Authors: Okamoto Yasuaki , Adachi Toshinori , Maezawa Akinori , Imanaka Toshinobu
Published: July 2006

The effect of ZnO addition on cobalt–alumina interaction modes was studied using TPR and XPS. It was found that the addition of 2 wt% ZnO markedly affects the distribution of the cobalt species in CoO/Al2O3 (5 wt% CoO): cobalt–alumina surface interaction species are removed and migration of cobalt into an alumina subsurface phase is promoted by ZnO. A formation of Co–Zn–O mixed oxide is proposed for ZnO–CoO/Al2O2O3 at high ZnO content. The dispersion and distribution of ZnO on Al2O3 are also strongly modified by the presence of cobalt.
The Reaction of (Arylthio)trimethylstannanes with 1-Aryl-1-bromoethanes: Effect of Substituent on the Process Shifting from Unimolecular to Bimolecular Substitution
Authors: Kozuka Seizi , Nakamura Hisashi
Published: July 2006

A kinetic study has been conducted on the reaction of (arylthio)trimethylstannanes with 1-aryl-1-bromoethanes. The reaction of the arylbromoethane bearing an electron-donating substituent was found involving unimolecular ionization of the arylbromoethane. The other reactions, however, were found to be second-order reactions. The nature of the second-order reactions was shifted from one involving unimolecular ionization as the minor process, to a clear bimolecular nucleophilic reaction, according to the electron-withdrawing nature of the substituents on the arylbromoethanes.
Local Structure of Polyethylene Glycol–Nal Solid Polyelectrolyte as Studied by 13C and 23Na NMR
Authors: Ueda Takahiro , Ohki Hiroshi , Nakamura Nobuo , Chihara Hideaki
Published: July 2006

13C CP/MAS NMR, 23Na powder NMR, and 23Na two dimensional nutation NMR were applied to complexes of Nal with polyethylene glycol (PEG) and tetraethylene glycol (TEG) to study the conformation of the polyethers and local structure around the Na+. 13C chemical shift data suggest strongly that the polyether chains assume the gauche conformation in the complexes. 23Na NMR spectrum of TEG–Nal complex gave a broad asymmetric line; simulation of the line shape led to e2Qq⁄h=590 kHz and η=0.7. No significant temperature dependence of the line shape was observed between 200 K and room temperature. For PEG–Nal complex e2Qq⁄h and η were estimated to be about 320 kHz and 0.7, respectively, from the nutation spectrum. On the basis of the above results, new model structures of PEG–Nal complex were presented.
Combined Temperature-Programmed Reduction (TPR)- Temperature-Programmed Desorption (TPD) Study of Supported Platinum Catalysts
Authors: Ebitani Kohki , Hattori Hideshi
Published: July 2006

Successive temperature-programmed desorption (TPD) after temperature-programmed reduction (TPR) (Combined TPR-TPD) was performed in order to characterize supported platinum catalysts (Pt/SiO2, Pt/Al2O3, Pt/ZrO2 and Pt/TiO2) as well as to judge the validity of the apparent TPR profiles. In successive H2-TPD runs obtained after cooling in the absence of hydrogen from 450°C to room temperature, the hydrogen desorption peak was observed only for the Pt/TiO2 sample, indicating that the hydrogenic species were kept on Pt/TiO2 sample, while no hydrogenic species were retained on the other samples after TPR up to 450°C. For both Pt/Al2O3 and Pt/TiO2 samples, hydrogen spillover seemed to proceed. Hydrogen incorporation during TPR was greater for Pt/TiO2 than for the others. This hydrogen spillover causes an overestimation of the consumed H2/Pt value determined by the apparent TPR profile for Pt/TiO2. For Pt/SiO2 and Pt/ZrO2 samples, the apparent TPR profiles were mostly due to a reduction of the supported Pt oxides. For the Pt/TiO2 sample, the hydrogen incorporation/emission at different temperatures during TPR was investigated. To generate SMSI states, desorption of the spiltover hydrogen is suggested to play a significant role; the role of hydrogen incorporation/emission in the generation of SMSI states is also discussed.
X-Ray, Electrical and Catalytic Studies of the System CoFe2O4–Co2TiO4
Authors: Dube Gulabshankar Ramkhelawan , Darshane Vishnu Shivram
Published: July 2006

The system Co1+xFe2−2xTixO4 has been studied with a view to investigating the cation distribution and to correlate the catalytic behavior of spinel with electrical and structural properties. To investigate cation distribution, techniques like X-ray diffraction, electrical conductivity, and thermo emf. have been used. The catalytic evaluation was carried out in the temperature range of 473–673 K using benzyl alcohol as a probe molecule. Our results show CoFe2O4 to be better catalyst for benzyl alcohol decomposition compared to Co2TiO4 or pure oxides of the system.
Association of Tris(acetylacetonato)chromium(III) with Chlorinated Phenols in the Liquid–Liquid Partition System
Authors: Katsuta Shoichi , Imura Hisanori , Suzuki Nobuo
Published: July 2006

The liquid–liquid partition behavior of tris(acetylacetonato)chromium(III) ([Cr(acac)3]) between heptane and 0.10 mol dm−3 aqueous sodium perchlorate solutions has been studied in the presence of a series of chlorinated phenols (HA) at 298.2 K. A large enhancement of the partition coefficient of [Cr(acac)3] with HA has been observed, e.g., it rises by about 1000-fold in the presence of 0.02 mol dm−3 3,5-dichlorophenol in the organic phase. This effect is ascribable to the association of [Cr(acac)3] with HA in the organic phase. From a partition-equilibrium analysis, the association complexes have been identified as being [Cr(acac)3]·iHA (i=1,2), and the association constants (βass,i) determined. The βass,i, value increases with an increase of the acid-dissociation constant of HA in the family of HA with the same combination of substituents at the 2,6-positions, i.e., the association is due to hydrogen bonding of the hydroxyl hydrogen atom of HA to [Cr(acac)3]. A linear free-energy relationship has been found between the βass,i, values of [Cr(acac)3] and those of [Co(acac)3] previously reported.
Molecular and Crystal Structure of Azobenzene-Containing Amphiphile, C6AzoC10N+Br−
Authors: Xu Guiqing , Okuyama Kenji , Shimomura Masatsugu
Published: July 2006

A totally synthetic azobenzene-containing amphiphile C32H52N3O3Br (C6AzoC10N+Br−) was crystallized from its solution in trichloromethane and ethanol. The crystal is triclinic with space group P\bar1; Z=2; a=24.317(5), b=8.632(1), and c=8.043(2) Å; and α=91.41(2), β=80.62(2), and γ=99.01(1)°. The structure was solved by the direct method and refined by the full-matrix least-squares method: R=0.038 for 4305 observed reflections (2θ<120°, Cu Kα, λ=1.5418 Å). Two molecules in a unit cell are related by a center of symmetry and pack tail-to-tail in a bilayer structure. The plane of the azobenzene chromophore is almost perpendicular to the layer surface and is overlapped with that of the azobenzene chromophore along its long axis with a separation of 3.55 Å. Different from other homologous compounds, this molecule bends almost 90° at the neck of the hydrophilic head group.
The Design of Amino Hydroxamic Metal Chelates and Their Activity in Biological Systems. Formation Constants between 2-Amino-4-methylpentanehydroxamic Acid with Proton, Copper(II), and Iron(III) in Aqueous Solution
Authors: Leporati Enrico , Nardi Gianluca
Published: July 2006

The complex-formation equilibria and relative stability constants of species present in aqueous solution of copper(II) and iron(III) with “l-leucinehydroxamic acid” (2-amino-4-methylpentanehydroxamic acid, ahmpe) have been determined by using potentiometric and spectrophotometric titrations in 0.5 mol dm−3 KCl solution at 25°C. Their acid-base reaction stoicheiometries have been evaluated and the protonation constants calculated from potentiometric data with the aid of the GAUSS Z and SUPERQUAD programs. The complex formation constants have been determined by using SQUAD (absorbance data), SUPERQUAD and STBLTY (potentiometric data) programs. The ligand is bound to the metal ions through the coordination of the N atoms of the α-amino group and the deprotonated –NHO− group in copper(II)–ahmpe system. For iron(III)–ahmpe system the coordination is referred to oxygen atoms of carboxylate and hydroxamate moieties. The UV-visible studies provide important evidence for the formation of several complex species depending on the pH. The experimental curves [ε=f(λ)], deduced from refinement of absorbance data with the program SQUAD, have been split up into precisely positioned absorption bands by Gaussian analysis using a nonlinear least-squares computer program NLIN. So the solution electronic spectra have been also employed to estimate the coordination sphere and have let us to suppose a weak tetragonal coordination [CuL2(H2O)2] and octahedral for Fe3+ complexes. The determination of formation constants and the coordination pattern proposed have a great interest in terms of metal chelate structures and their important role in biological systems.