bluuebunny/crossref_metadata_2025 huggingface dataset:
Phosphorescent State of p-Fluorobenzaldehyde
Authors: Uejoh Kazuya , Shimokozono Makoto , Koyanagi Motohiko
Published: July 2006

Phosphorescence spectra of p-fluorobenzaldehyde have been observed in (i) the vapor phase at room temperature and in (ii) methylcyclohexane and (iii) methyl benzoate matrices at 4.2 K. From the vibrational analysis and deuteration effect it is established that the phosphorescent state is nπ* in cases i and ii while it is ππ* in case iii. A close similarity between the vapor phase emission spectra of p-fluorobenzaldehyde and benzaldehyde leads us to the conclusion that the substitution of the fluorine atom for the para hydrogen atom of benzaldehyde has little effect to the both triplet states. Several experimental data for low frequency vibrations in the excited 3nπ* state will be given by analyzing hot sequence bands of the vapor phosphorescence spectrum.
Synthesis of 2,9-Dichloro-1,10-phenanthroline from N,N′-Annelated Phenanthrolinediones
Authors: Yamada Masaki , Nakamura Yoshio , Kuroda Shigeyasu , Shimao Ichiro
Published: July 2006

Though the chlorination of an N,N′-annelated phenanthrolinedione, 3,6,7,9-tetrahydro-5H-[1,4]diazepino[1,2,3,4-lmn][1,10]phenanthroline-3,9-dione, gave 2,9-dichloro-1,10-phenanthroline, another dione, 3,5,6,8-tetrahydropyrazino[1,2,3,4-lmn][1,10]phenanthroline-3,8-dione, did not. It demonstrated a simultanous introduction of two chlorine substituents to non-substituted 1,10-phenanthroline via only the former intermediate.
Preparation of Tin(II) Oxide by a Homogeneous Precipitation Method
Authors: Fujita Kazumi , Nakamura Chizuko , Matsuda Keizo , Mitsuzawa Shunmei
Published: July 2006

The production of tin(II) oxide from tin(II) chloride and urea was found to depend on the concentration of urea. An amorphous compound was produced for a lower concentration of urea, 5SnO·2H2O was produced for a higher concentration of urea, and tin(II) oxide was produced for a middle-range concentration of urea.
Growth of CaWO4 Crystals from M2WO4(M=Li, Na, and K) Fluxes
Authors: Oishi Shuji , Hirao Minoru
Published: July 2006

Calcium tungstate crystals were grown from M2WO4 (M=Li, Na, and K) fluxes. Observations of the obtained CaWO4 crystals showed that a high-temperature solution of Na2WO4 was superior to both Li2WO4 and K2WO4 solutions. It was experimentally confirmed that the Na2WO4 flux chosen on the basis of the guiding principle was the most suitable.
Hydrodesulfurization of Dibenzothiophene on Iron-Exchanged Y Zeolite
Authors: Nagai Masatoshi , Matsumoto Kaoru , Uetake Kazuya , Sakikawa Noriyuki
Published: July 2006

An Fe(II)HY zeolite catalyst pretreated at 500 and 600 °C was highly active for the hydrodesulfurization of dibenzothiophene when the Fe(II)HY zeolite was exchanged in a solution of FeCl2 and aqueous NH3 with NaY in N2 gas, whereas the Fe(III)NaY catalyst in a solution of FeCl3 displayed a low activity.
EPR Study of the Precursors of Chelate Paramagnetic Complexes Formed in Photochemical Reactions of [Mo(cp)(CO)3]2 (cp=η5-C5H5) with o-Quinones
Authors: Hanaya Minoru , Iwaizumi Masamoto
Published: July 2006

Experimental evidence has been obtained by EPR spectroscopy for the paramagnetic precursors expected in the photochemical reactions of [Mo(cp)(CO)3]2 with o-quinones to produce paramagnetic chelate complexes.
Approximation Method for Solution of Rate Equations in Homogeneous Reaction Field
Authors: Fukutani Seishiro , Sakaguchi Keizo , Jinno Hiroshi
Published: July 2006

Analysis of a reaction mechanism by assembling the scheme with elementary reactions requires numerical solution of the reaction rate equations. The numerical procedure is time-consuming because of the stiffness of rate equations particularly when temperature varies with the reaction progress. This investigation proposed an approximation method which can save computational time for solving reaction rate equations in a homogeneous reaction field. The approximation method reduces the rate equations, which are a set of simultaneous differential equations, to independent differential equations for each species by simplifying the original equations according to the reaction characteristics; the resultant differential equations can be solved analytically within small time intervals. The validity of these differential equations was verified by comparing the obtained changes in temperature and the species concentrations in hydrogen combustion with those calculated from the original equations with the Runge–Kutta–Gill method.
Theoretical Evidence for the Presence of Linear Polyacenes in the Interstellar Medium
Authors: Aihara Jun-ichi
Published: July 2006

Duley and Jones recently proposed that small linear polyacenes (e.g., anthracene) were responsible for the IR emission observed in localized regions of some UV-excited nebulae. Linear polyacenes are relatively stable in the first excited state although they are not very stable in the ground state. This probably is the primary reason why this type of benzenoid hydrocarbons are observed in the interstellar medium.
Asymmetric Hydrogenation of α-Keto Acid Derivatives with Rh(I)–Chiral Diphosphinite System. Effect of Halide Counterion on the Asymmetric Induction
Authors: Yamagishi Takamichi , Ikeda Satoru , Egawa Tatsuya , Yamaguchi Motowo , Hida Mitsuhiko
Published: July 2006

A chiral diphosphinite ligand having dicyclohexylphosphinooxy and dimethylamino moieties (Cy-POP-AE) was effective for the asymmetric hydrogenation of N-(benzoylformyl) amino acids by a Rh(I) catalyst under mild conditions. A neutral rhodium(I) precursor enabled a double asymmetric induction in methanol, while a cationic precursor caused an asymmetric induction controlled mainly by the substrate chirality.
Novel Electron Acceptors Bearing a Heteroquinonoid System III: 2,5-Bis(dicyanomethylene)-2,5-dihydrofuran and Its Conjugated Homologues as Novel Oxygen-Containing Electron Acceptors
Authors: Ishida Hideki , Yui Koji , Aso Yoshio , Otsubo Tetsuo , Ogura Fumio
Published: July 2006

2,5-Bis(dicyanomethylene)-2,5-dihydrofuran with a 2,5-furanoquinonoid skeleton and its extensive conjugated homologues, 5,5′-bis(dicyanomethylene)-5,5′-dihydro-Δ2,2′-bifuran (8a), and 5,5″-bis(dicyanomethylene)-5,5″-dihydro-Δ2,2′:5′,2″-terfuran (12a), have been prepared as a new type of oxygen-containing electron acceptors. In the synthetic course of the tetrabromo derivative of 12a, 3′,4-dibromo-5-(3,5-dibromo-2-furyl)-3,5′-bis(dicyanomethylene)-3,5′-dihydro-Δ2,2′-bifuran was also obtained as an unsymmetrical isomer possessing an unusual 2,3-furanoquinonoid conjugation, whose structure was confirmed on the basis of X-ray crystallographic analysis. In addition, X-ray analysis of the TTF complex of 8a revealed that the bifuranoquinonoid conjugation has a trans form. These furanoquinonoid compounds behaved as weak electron acceptors, and accordingly failed to form conductive complexes. However, the 3,3′-dibromo derivative of 8a gave the TTT complex of a very high electrical conductivity.
Synthesis and Reactions of Phosphine–Methylsulfonyloxyborane Complexes
Authors: Oshiki Toshiyuki , Imamoto Tsuneo
Published: July 2006

Functionalizations of the boranato group of phosphine–boranes have been investigated. Trimethylphosphine–borane readily reacted with methanesulfonic acid in dichloromethane with evolution of hydrogen. The resulting trimethylphosphine–methylsulfonyloxyborane was subjected to nucleophilic substitution reaction on the boron atom with arenethiols or secondary phosphine–boranes in the presence of NaH. The reactivities of the substitution products obtained were also investigated. A new phosphine–borane having a P–B–P–B–P–B–P–B bond linkage was synthesized.
Highly Selective Cis-Trans Photoisomerization of 1-Pyrenylethylenes: Relations between the Modes of Isomerization and Potential Energy Surfaces
Authors: Okamoto Hiroaki , Arai Tatsuo , Sakuragi Hirochika , Tokumaru Katsumi
Published: July 2006

Among 1-pyrenylethylenes with an alkyl (t-butyl) or an aryl (phenyl) group on the β ethylenic carbon, 1-(3,3-dimethyl-1-butenyl)pyrene (BP) undergoes cis-to-trans one-way isomerization on benzil sensitization, whereas 1-styrylpyrene (SP) undergoes mutual isomerization between the cis and trans isomers to afford an extremely high photostationary state composition (98%) of the trans isomer. Transient spectroscopy and measurements of the isomerization quantum yields revealed that the trans triplet state is the most stable and populated conformation on the triplet energy surface for both BP and SP; however, a higher degree of stabilization of the trans conformation for BP than for SP compared to the perpendicularly twisted conformation makes BP and SP one-way and two-way isomerizing, respectively.
Normal Vibrations of 5-Chloro-, 5-Bromo-, 5-Methyl-, and 2-Methylpyrimidines
Authors: Ikari Yoshihiro , Sakamoto Hironobu , Nakama Sekiichiro , Nibu Yoshinori , Shimada Hiroko , Shimada Ryoichi
Published: July 2006

Assignment of the normal vibrations of 5-chloro-, 5-bromo-, 5-methyl-, and 2-methylpyrimidines was made through the vibrational analyses of the polarized Raman and infrared spectra and also through the normal coordinate calculation. The normal vibrations of 5-halo- and 5-methylpyrimidines were compared with those of 2-halo- and 2-methylpyrimidines, and a substitutional effect on the vibrational frequencies and modes of the hydrogen bending and wagging vibrations was studied.
Novel Reduction of Carbonyl Compounds with Al/NH3/Halide under Irradiation of Ultrasonic Wave
Authors: Sato Ryu , Nagaoka Takeshi , Goto Takehiko , Saito Minoru
Published: July 2006

Various carbonyl compounds, such as benzophenones and acetophenones, were reduced by Al/NH3/halide under ultrasonic wave irradiation to give the corresponding monohydric alcohols and/or pinacols in satisfactory yields. The addition of inorganic halides improved the selectivity in the formation of monohydric alcohols and pinacols.
The Control of the Phenylglyoxylic Acid Permeation Rate through a Liquid Membrane of a Toluene–Chloroform Mixture Containing Magnetite under a Rotating Magnetic Field and an Alternating Magnetic Field
Authors: Sakai Yasuzo , Kumakura Hiroyuki , Takahashi Fujio
Published: July 2006

A liquid membrane containing ferromagnetic powder (LM-FP) was proposed for controlling the molecular permeation rate through a liquid membrane in a rotating magnetic field (R-MF) in a previous paper. This paper presents details concerning the property of LM-FP under exposure to R-MF or an alternating magnetic field (A-MF). Magnetite and phenylglyoxylic acid (PGA) were used as a ferromagnetic powder and a substance for permeation, respectively. Various factors, such as the magnetite concentration in LM-FP, the intensity of the magnetic field and the number of rotations of R-MF, both of which affect the PGA permeation rate, were investigated in order to understand the behavior of magnetite powder in LM-FP. Magnetized particles of magnetite powder in LM-FP were found to rotate in R-MF, but not to move in A-MF. R-MF exerted an acceleration of the PGA permeation rate through LM-FP more than did A-MF. It is suggested that magnetized particles of magnetite powder behave as micro-magnetic stirrers in LM-FP to accelerate molecular transport. Data concerning the PGA permeation rate were simulated by assuming a concentration change of PGA in LM-FP after turning R-MF on or off. We obtained simulation curves which were in accord with the experimental results.
Correlation of Viscosity and Conductance with 23Na+ NMR T1 Measurements
Authors: Price William S , Chapman Bogdan E , Kuchel Philip W
Published: July 2006

The relationship between rotational correlation time and the translational diffusion coefficient (Stokes–Einstein equation) of sodium ions dissolved in a series of water–glycerol solutions was studied. NMR longitudinal relaxation measurements gave an estimate of the rotational correlation time for the hydrated sodium ion. From this, using the Debye and Stokes–Einstein equations the translational diffusion coefficient was calculated. These results were compared with estimates of the sodium ion diffusion coefficient obtained using pulsed field gradient NMR. The simple, chemical system was chosen for this study so that the nature of the sodium relaxation would be unambiguous. Also, conductivity measurements were performed on each solution since the conductivity is intimately related to the rate of ionic diffusion. The results showed that due to the spherical nature of the hydrated sodium ion the Debye and Stokes–Einstein equations are well obeyed allowing translational diffusion coefficients to be calculated from rotational correlation times in good agreement with those measured using pulsed field gradient NMR.
AMI and CNDO/S Study of 2,5-Dimercapto-1,3,4-thiadiazole, the Mesoionic 1,3,4-Thiadiazolo[2,3-b][1,3]thiazine-2-thione and Its Dimerization Derivative
Authors: Buemi Giuseppe
Published: July 2006

The molecular geometries of the mesoionic 1,3,4-thiadiazolo[2,3-b][1,3]-thiazine-2-thione (II) and its dimerization product, 1,10-dithia[4.4](3,5)-1,3,4-thiadiazolinophane-6,15-dithione (III) have been optimized by means of the AMI method. Their electronic spectra, as well as those of the parent 2,5-dimercapto-1,3,4-thiadiazole (I), have been calculated at CNDO/S level. The analysis of the calculated electronic transitions and of the experimental UV absorption bands confirms the mixed thiolic–thionic structure of I as the most stable one, in agreement with 4-31G* prediction. The electronic transitions of compound III are practically coincident with those found for I; on the contrary, a band in the visible and a band in the UV region are predicted for compound II, so accounting for the yellow color of II and the lack of color of III.
Micellar Effects upon Spontaneous and Alkaline Hydrolysis of t-Butyl Phenyl Carbonate
Authors: Al-Lohedan Hamad A , Al-Hassan Mohammed I
Published: July 2006

Cationic micelles of hexadecyltrimethylammonium ion HTAX (X=Cl− and OH−) catalyzes the reactions of t-butyl phenyl carbonate with OH− and kΨ goes through maximum with increasing [HTACl] but it continues to increase with increasing [HTAOH]. Spontaneous hydrolysis of t-butyl phenyl carbonate is inhibited by both cationic and anionic micelles. The second-order rate constant in micelles is smaller than that in water.
Transport of d-Glucosamine through a Supported Liquid Membrane System Using Lipophilic Aldehyde as a Carrier
Authors: Yoshikawa Masakazu , Mori Yoshikazu , Tanigaki Masataka , Eguchi Wataru
Published: July 2006

Transport of amino compound relevant to biology, d-glucosamine, was carried out with a supported liquid membrane using a lipophilic aldehyde, 4-octadecyloxybenzaldehyde, as a carrier. In the present membrane transport system, a reversible organic reaction, Schiff base formation reaction, between amino group in d-glucosamine and aldehyde group in carrier was utilized as a molecular recognition reaction.
Surface-Active Properties and Their Photochemical Behaviors of (1-Alkyl-4-pyridiniomethyl)phosphonates
Authors: Okamoto Yoshiki , Hosoda Asao , Takamuku Setsuo
Published: July 2006

(1-Alkyl-4-pyridiniomethyl)phosphonates bearing long alkyl-chains of even carbon numbers of 8 to 18 were prepared. They exhibited the characteristics of surface-active agents. Upon irradiation in alkaline aqueous media, the phosphonates underwent the C–P bond cleavage to give 1-alkyl-4-methylpyridinium phosphates and as a result the surface tension of the solution also changed. The two-fold increases of the quantum yields of the C–P bond cleavage were found at their critical micelle concentrations.
The 310-Helical Conformation of Aib-Containing Oligopeptide, Boc–(l-Leu–Aib2)2–OBzl
Authors: Okuyama Kenji , Nakanishi Shousuke , Saga Yuji , Umeyama Hiroshi , Narita Mitsuaki
Published: July 2006

The molecular and crystal structure of the Aib (α-aminoisobutyric acid)-containing oligopeptide, Boc–(l-Leu–Aib2)2–OBzl, are determined by X-ray diffraction analysis. The hexapeptide crystallizes in the space group P21, with a=19.912(2), b=16.098(1), c=14.710(2) Å, β=96.81(1)°, and Z=4. The unit cell contains two independent molecules (molecules A and B) in the asymmetric unit. The dihedral angles (φ and ψ) of the peptide back bone show that molecule A folds into a right-handed helix and molecule B folds into a left-handed helix. Both the molecules adopt a 310-helical conformation stabilized by four 4→1 intramolecular hydrogen bonds. The right- and left-handed helical molecules are arranged alternately, in head-to-tail fashion to make columns along the [101] direction. These columns are packed closely in the pseudo-hexagonal arrangement.
Synthesis and Properties of Extended Tridecafulvenes. The Substituent Effect on the Paratropicity of This Fulvene System as a Measure of Polarizability
Authors: Ojima J\={u}ro , Kitamura Keiko , Sugimori Haruyoshi , Higuchi Hiroyuki , Iyoda Masahiko
Published: July 2006

The vinylogues of 14,14-dicyano-5,10-dimethyl-6,8-bisdehydrotridecafulvene have been synthesized and the effect of increasing exocyclic double bonds upon the paratropicity of the thirteen-membered ring is discussed by comparing the polarizability of 2,2-dicyanovinyl, 4,4-dicyano-1,3-butadienyl, and 6,6-dicyano-1,3,5-hexatrienyl groups.
Optical Resolution by Replacing Crystallization of Dl-Threonine
Authors: Shiraiwa Tadashi , Yamauchi Masahiro , Yamamoto Yumi , Kurokawa Hidemoto
Published: July 2006

Optical resolution by replacing crystallization of Dl-threonine (Dl-Thr) was achieved in the presence of an equimolar amount of l-proline as an optically active cosolute. This optical resolution gave d-Thr with 91% optical purity in 78% degree of resolution, and optically pure l-Thr was obtained from the mother liquor.
Foam Ratio as a Measure for Mechanical Foam-Breaking in Gas Bubbling Systems
Authors: Yasukawa Masami , Yamagiwa Kazuaki , Ohkawa Akira
Published: July 2006

The volume fraction of liquid in foam, designated as the foam ratio, was measured for a gas-bubbling system using various foaming liquids. The foam ratio can be used as a substantial measure of the dynamic foaming capacity for gas-bubbling systems. The applicability of the foam ratio for evaluating the performance of mechanical foam-breaking was investigated. Furthermore, the effect of the operating conditions on the foam ratio was related to the extent of mechanical foam-breaking.
The Catalytic Isomerization of Butenes over a Samarium Oxide
Authors: Nakashima Yasushi , Sakata Yoshihisa , Imamura Hayao , Tsuchiya Susumu
Published: July 2006

The ratio, cis-2-/trans-2-butene, formed from 1-butene isomerization, was 22.2. The reaction profile of butenes isomerization obtained from the relative rate constants was of the cis-convex type. The basic sites on the oxide surface have been revealed by the benzoic acid titration method.
Electrical Conductivity and Thallium Spin-Lattice Relaxation Time Measurements of Tl4HgBr6 and Tl4HgI6
Authors: Nagase Hirokazu , Furukawa Yoshihiro , Nakamura Daiyu
Published: July 2006

The ionic transport properties of Tl4HgBr6 and Tl4HgI6 were investigated with 205Tl spin-lattice relaxation time (T1) and electrical conductivity (σ) measurements. The temperature dependence of 205Tl T1 shows that Tl+ ion diffusion is activated at high temperatures in both crystals. The activation energies of diffusion were estimated to be 47 and 55 kJ mol−1 for Tl4HgBr6 and Tl4HgI6, respectively, from the temperature dependence of σ.
The Selective Protection of Uridine with a p-Methoxybenzyl Chloride: A Synthesis of 2′-O-Methyluridine
Authors: Akiyama Takahiko , Nishimoto Hiroyuki , Ozaki Shoichiro
Published: July 2006

2′-O-Methyluridine was prepared through 5 steps from uridine by use of p-methoxybenzyl group (PMB) as an N3-protecting group of uridine. A chemoselective protection method has been developed by use of DBU as a base and deprotection was effected by AlCl3–anisole system.
Spectrophotometric Studies on Complexation Reaction of Some Water-Soluble 5-Nitro-2-Pyridylhydrazones with Bickel(II) and Determination of Trace Nickel with α-(2-Benzimidazolyl)-α-(5-nitro-2-pyridyl)hydrazono-3-toluenesulfonic Acid
Authors: Ishii Hajime , Odashima Tsugikatsu , Kawamonzen Yoshiaki
Published: July 2006

The complexation reaction of four water-soluble hydrazones, α-(5-nitro-2-pyridyl)hydrazono-α-(2-quinolyl)-3-toluenesulfonic acid (NPHQTS), α-(5-nitro-2-pyridyl)hydrazono-α-(2-thiazolyl)-3-toluenesulfonic acid (NPHTTS), α-(2-benzothiazolyl)-α-(5-nitro-2-pyridyl)hydrazono-3-toluenesulfonic acid (BTNPHTS) and α-(2-benzimidazolyl)-α-(5-nitro-2-pyridyl)hydrazono-3-toluenesulfonic acid (BINPHTS), with nickel(II) has been studied spectrophotometrically. These hydrazones react with nickel(II) to form a stable 1:2 (metal: ligand) complexes with high molar absorptivities. A sensitive and selective spectrophotometric method for the determination of nickel with BINPHTS has been developed. The nickel–BINPHTS complex is formed quantitatively in the pH range 6.5–8.9 and its absorption spectrum shows a maximum at 498 nm. Beer’s law is obeyed over the range 0.02–0.8 μg cm−3 of nickel and the apparent molar absorptivity of the complex is 8.67×104 dm3mol−1cm−1 at 498 nm. The proposed method was applied to the determination of nickel in manganese nodule samples, satisfactory results being obtained. Furthermore, the overall formation constants of nickel complexes of the four hydrazones were also determined spectrophotometrically.
The Synthesis of Isocyanurates on the Trimerization of Isocyanates under High Pressure
Authors: Taguchi Yoichi , Shibuya Isao , Yasumoto Masahiko , Tsuchiya Tohru , Yonemoto Katsumi
Published: July 2006

The trimerization of phenyl isocyanate in the presence of triethylamine was accelerated under high pressure to give triphenyl isocyanurate almost quantitatively. The reaction in benzene was remarkably accelerated by compression. The effects of pressure, temperature, catalysts, and solvents were examined on the trimerization of phenyl isocyanate. Aryl and normal alkyl isocyanates trimerized under high pressure to give the corresponding isocyanurates in good yields, whereas isocyanates having bulky alkyl groups such as t-butyl and cyclohexyl did not trimerize even under 800 MPa.
Investigation of the States of Water in Water-Swollen Hydrogels by Liquid Chromatography and Differential Scanning Calorimetry
Authors: Shibukawa Masami , Ohta Naoichi , Onda Nobuhiko
Published: July 2006

A new liquid chromatographic method was proposed for the estimation of the amount of water which exhibits selectivity to solutes in water-swollen hydrogels based on the model regarding the retention of ions on the column packed with the hydrogels. The estimated amount of the water in polyacrylamide, dextran, and poly(vinyl alcohol) gels corresponds to the sum of the amount of freezable bound water and that of nonfreezing water determined by means of differential scanning calorimetry. This means that the freezable bound water takes an important role in the separation process using water-swollen hydrogels contrary to the conventional view of the freezable water.
A Convenient Synthesis of (2R)-1-Amino-1-Deoxy-1-Phosphinylglycerols
Authors: Hanaya Tadashi , Miyoshi Akihiko , Noguchi Ayashi , Kawamoto Heizan , Armour Margaret-Ann , Hogg Alan M , Yamamoto Hiroshi
Published: July 2006

2,3-O-Isopropylidene-d-glyceraldehyde reacts with dimethylphosphine oxide in the presence of triethylamine to give separable (1S,2R)-and (1R,2R)-1-dimethylphosphinylgrycerol (65 :35), from which the (1R) and (1S) title compounds are respectively derived via 1-O-mesyl and 1-azido derivatives. The corresponding 1-dimethoxyphosphinylglycerols are similarly prepared. Structural and conformational assignments of these products are made on the basis of the 1H NMR data and [α]D values.
A New and Convenient Preparation of Conjugated Dienals
Authors: Yahata Nobuhiro , Fujita Makoto , Ogura Katsuyuki
Published: July 2006

For preparation of 5-monosubstituted or 5,5-disubstituted 2,4-dienals, 1-(methylthio)-5-(p-tolylsulfonyl)-1,3-pentadiene (4) is revealed to be an important precursor. When 5-(methylthio)-5-(p-tolylsulfonyl)-1,3-pentadiene, that is easily obtainable from (methylthio)methyl p-tolyl sulfone, was treated with silica gel, 1,5-rearrangement of p-tolylsulfonyl group occurred to give 4. The conditions for mono- or dialkylation of 4 followed by hydrolysis leading to the dienals are described.
Comparison of the Electrochemical Properties of Electric Double-Layer Capacitors with an Aqueous Electrolyte and with a Nonaqueous Electrolyte
Authors: Tanahashi Ichiro , Yoshida Akihiko , Nishino Atsushi
Published: July 2006

The electrochemical properties of phenolic resin-based activated carbon fiber cloth (ACFC) in an aqueous electrolyte and in a nonaqueous organic electrolyte have been investigated. The differential electric double-layer capacitance of ACFC with the specific surface area of 1630 m2 g−1 in the aqueous electrolyte was 1.50-times larger than that of the ACFC in the organic electrolyte. In accordance with the result, the capacitance of capacitors consisted of the ACFC and the aqueous electrolyte was 1.47-times larger than that of capacitors comprising ACFC and the organic electrolyte. The IR drop of capacitors with the aqueous electrolyte was smaller by one order of magnitude than that of capacitors with the organic electrolyte.
Photoexcitation of Potassium Octacyano-Tungstate (IV)-1,10-Phenanthroline System: Kinetics and Mechanism of the Reaction
Authors: Ali S I , Kaur Harpal
Published: July 2006

The kinetics of the reactions of photochemically generated [W(CN)7OH]4− in basic and [HW(CN)7(H2O)]2− in acidic medium with 1,10-phenanthroline have been studied in buffer solutions of pH 4.2–10.6, ionic strength 7.5×10−2 mol kg−1 at 20°C. Quantum yield for formation of photoproduct was calculated and it was found to depend on pH, ligand and, [W(CN)8]4− concentrations. The pseudo-first-order rate constant and quantum yield values in acidic medium are higher than in basic medium and the mechanisms of the photochemical substitution reactions are different in two mediums.
Electrolytically Generated Manganese(III) Sulfate for the Oxidation of l-Histidine in Aqueous Sulfuric Acid: a Kinetic Study
Authors: Pinto Ivan , Sherigara B S , Udupa H V K
Published: July 2006

Conditions have been established for the electrogeneration of Mn(III) from Mn(II) in sulfuric acid medium. Mn(III) formed was identified and characterized by UV spectra. Kinetics of Mn(III) oxidation of l-histidine in aqueous sulfuric acid medium has been studied spectrophotometrically. Oxidation followed second order kinetics in [Mn(III)], first order in [histidine] and increase in [H+] decreased the rate. The reduced product of the oxidant, Mn(II), retarded the rate of reaction. Evidence for the transient existence of the free radical reaction intermediate is given. Effects of ionic strength, solvent composition, HSO4− and certain complexing agents like P2O74−, Cl−, F−, have also been studied. Added complexing agents decreased the redox potential of the Mn(III)/Mn(II) couple, thereby reducing the oxidation rate. Dependence of reaction rate on temperature is examined and activation parameters computed from Arrhenius and Eyring plots. A mechanism consistent with kinetic results has been proposed in which a combined role of Mn(III)aq and MnOH2+aq was envisaged.
Acidic Property and Catalytic Activity of TiO2–SiO2–Al2O3
Authors: Sabu K R , Rao K V C , Nair C G R
Published: July 2006

The acidity evaluations using butylamine titration have been carried out to correlate the surface acidic properties of TiO2–SiO2–Al2O3 catalysts with their alkylating activity. The acid amount of TiO2–SiO2–Al2O3 of silica to alumina molar ratio 16.4 and titania content 10.4% (by weight) is nearly double that of SiO2–Al2O3 of the same silica to alumina molar ratio. The acid strength of TiO2–SiO2–Al2O3 coprecipitated from a solution of pH 2 and the acid amount of the same ternary oxide coprecipitated from solutions of higher pH(>6) are low.
Kinetics and Mechanism of Acid Hydrolysis of Bis(dicarboxylato)carbonatochromate(III) Complexes
Authors: Sai C S T , Anipindi N R , Subbiah V , Pandit M W
Published: July 2006

A study has been made of the acid-catalysed aquation reactions of three complex ions of the general formula [Cr(XX)2(CO3)]3−, where XX=oxalate, malonate, or methylmalonate, by stopped-flow spectrophotometry in the acid range 0.1–2.0 M (M=mol dm−3) and 20–35°C at an ionic strength of 2 M. Only the ring-opening reaction of the carbonate is observed, k=2.12, 3.28, and 4.02 M−1 s−1 at 25°C respectively for oxalato, malonato, and methylmalonato complexes as the subsequent decarboxylation is too fast to measure. The observed trend was explained in terms of the basicity of the coordinated inert ligands.
Application of Surface-Active Substances in Polarographic Determination of Hg(II), V(V), Fe(III), As(III), Sb(III), and Ti(IV) in the Presence of U(VI)
Authors: Ismail M I
Published: July 2006

The reduction of hexavalent uranium in 1 M H2SO4 at DME was found to be retarded by a non ionic surfactant Triton® X 100 and to shift the uranium wave to more negative potentials. Advantage was taken of this fact to determine the elements Hg(II), Fe(III), V(V), As(III), Sb(III), and Ti(IV) either individually in the presence of U(VI) or simultaneously in mixtures, a supporting electrolyte of 1 M H2SO4 containing 0.01% Triton® X 100 was used. The i1/C results gave excellent correlations in each case, as was indicated from the least squares regression analysis. The outcome results suggest the method validity as a quantitative method for determination of the studied elements.
Photoreduction of Aromatic Ketones in Hexamethylphosphoric Triamide (HMPA): Formation of Stable Coupling Products with HMPA
Authors: Kohmoto Shigeo , Kreher Thomas , Yamamoto Makoto , Yamada Kazutoshi
Published: July 2006

Irradiation of aromatic carbonyl compounds in hexamethylphosphoric triamide (HMPA) resulted in the cross-coupling of ketyl radicals with the HMPA-derived radical generated via hydrogen abstraction from it. The results on acetolysis, methanolysis, and the reaction with thionyl chloride of the resulting coupling products are described.
Thermal Decomposition and Mass Spectra of Phosphoramidate Esters
Authors: Shimasaki Choichiro , Mutou Yoshinori , Tsukurimichi Eiichi , Yoshimura Toshiaki
Published: July 2006

Thermal decomposition of diphenyl phosphoramidate (1)and phenyl phosphordiamidate (2) was investigated by DTA-TG, IR, 1H NMR, 31P NMR, mass spectroscopy, and TG-GC/MS. The DTA-TG/DTG curve showed that the thermal decomposition of 1 occurred in one stage. Compound 1 melted at about 150°C and decomposed to polyphosphates accompanied with a weight loss of about 60% in the temperature region of 200 to 350°C. It was confirmed from the results of IR, 1H NMR, and TG-GC/MS that this weight loss in TG of 1 is attributed to the liberation of ammonia and phenol and to the production of an insoluble polyphosphate through triphenyl phosphate or a soluble oligophosphate. The fragment ions of diphenyl ether (m⁄z 170) and aniline (m⁄z 93) were recognized in the mass spectrum of 1. This result indicates that phenyl radical and hydrogen atom in both samples transfer between three oxygen atoms and a nitrogen atom around a phosphorus atom. The activation energy of the thermal decomposition was estimated to be 151 kJ mol−1 for 1 and 220 kJ mol−1 for 2. From the DTA-TG/DTG curve of 2, the decomposition in TG showed two stages and proceeded in a similar process to 1. The cleavage of 2 by the electronic impact was also similar to that of 1.
Synthesis of Ferrocenyl-Substituted 3-Cyano-2-methylpyridines
Authors: Shibata Katsuyoshi , Katsuyama Isamu , Matsui Masaki , Muramatsu Hiroshige
Published: July 2006

Ferrocenyl-substituted 3-cyano-2-methylpyridines were easily prepared by the sonication of α,β-unsaturated carbonyl compounds substituted by ferrocenes in acetonitrile in the presence of potassium t-butoxide.
Chemical Behavior of Coenzyme PQQ toward Aminoguanidine: Redox Reaction and Adduct Formation
Authors: Mure Minae , Nii Kazumi , Itoh Shinobu , Ohshiro Yoshiki
Published: July 2006

The reaction of coenzyme PQQ with aminoguanidine, which is known as an inhibitor of quinoprotein amine oxidases, was investigated in vitro. The redox reaction predominantly proceeded at pH 10.0 to give PQQH2 (quinol), whereas deactivation of PQQ occurred at pH 6.7 to give the triazine adduct. In the case of semicarbazide or acetohydrazide as the substrate, azo adduct formation was mainly observed even at pH 10.0. Importance of the C-5 carbinolamine-type intermediate a is discussed.
Synthesis of Layered Polysilicic Acid–Acrylamide Intercalation Compounds and Polymerization in the Interlayer Spaces
Authors: Yanagisawa Tsuneo , Yokoyama Chika , Kuroda Kazuyuki , Kato Chuzo
Published: July 2006

Layered polysilicic acid–acrylamide intercalation compounds were synthesized by the reaction of H-magadiite (H2Si14O29·xH2O) and H-kenyaite (H2Si20O41·xH2O) with acrylamide saturated aqueous solutions. The formation of the intercalation compounds were ascertained by X-ray powder diffraction, IR, 13C-CP MAS NMR, DTA, and chemical analysis. However, when H-magadiite was used, a part of the intercalated acrylamide molecules was oligomerized during the intercalation. A heat treatment of the layered polysilicic acid–acrylamide intercalation compounds led to a polymerization of the acrylamide in the interlayer spaces.
The Reflectance Spectra of (BEDT-TTF)5Hg3Br11 and (BEDT-TTF)HgBr3. The Estimation of Effective On-Site Coulomb Interaction
Authors: Tajima Hiroyuki , Tamura Masafumi , Kuroda Haruo , Mori Takehiko , Inokuchi Hiroo
Published: July 2006

The reflectance spectra of (BEDT-TTF)5Hg3Br11 and (BEDT-TTF)HgBr3 were measured by using the microspectrophotometric technique in the spectral range from 450 cm−1 to 25000 cm−1. In the former salt, the gap formation due to a metal-insulator transition was observed in the reflectance spectrum at 100 K. In the latter salt, the effective Coulomb interaction and the intra-dimer transfer integral were estimated and compared with the corresponding values of BMDT-TTF and TTF.
The Ionization Constants of Nitrobenzoic and Benzoic Acids in Water-Ethanol Mixture at 25 °C from Conductance Measurements
Authors: Niazi M S K , Khan M Zafar Iqbal , Ali J , Ahmad M
Published: July 2006

Molar conductances of dilute solutions of 2-, 3-, 4-nitrobenzoic and benzoic acids are reported at 25°C in ethanol–water (EtOH–H2O) mixtures over composition range from 0 to 70 wt% of ethanol. The ionization constants and limiting molar conductances of these acids have been computed from the data using Fuoss 1978 conductance equation. Solvent effect on the ionization of acids in EtOH–H2O mixtures has been discussed in terms of free energy of transfer of respective anions of the acids from H2O to EtOH–H2O mixtures. It is found that the order of ionization of these acids in EtOH–H2O system is 2-nitrobenzoic acid>3-nitrobenzoic acid \simeq4-nitrobenzoic acid>benzoic acid.
Magnetic Studies of Some Benzamide Derivatives
Authors: Abdel-Kader M M
Published: July 2006

The diamagnetic susceptibilities of benzamide, methylbenzamides, and hydroxybenzamides have been accurately measured. From these measurements and the calculated values of the in-plane susceptibilities, the semi-experimental anisotropies have been obtained. The magnetic data are correlated with the arrangement of these molecules in the crystals.
The Reductions of Azido–, Thiocyanato–, and Isothiocyanato–pentacyanocobaltate(III) Anions by Titanium(III) in Aqueous Acidic Solution
Authors: Oyetunji Olayinka , Olubuyide Olusegun , Ojo J Folorunso
Published: July 2006

The reductions of azido–, thiocyanato–, and isothiocyanato–pentacyanocobaltate(III) anions by aquatitanium(III) have been studied in aqueous solution with I=1.0 mol dm−3 (LiCl) T=25°C. The reactions are found to have inverse acid dependence of the form: kobsd=kK⁄(K+[H+]).The estimated values of k and K are 1.47 dm3mol−1 s−1 and 1.0×10−2 mol dm−3 for the azido complex and 4.85 dm3mol−1s−1 and 6.0×10−3 mol dm−3 for the thiocyanato complex. Various criteria including the kN3−⁄kNCS− and kSCN−⁄kN3− ratios among others are used to suggest inner-sphere mechanism for these reactions.
Extraction–Spectrophotometric Determination of Chromium(VI) with Hydroxyamidines
Authors: Golwelker A , Patel K S , Mishra R K
Published: July 2006

A new, simple, rapid, and selective spectrophotometric method for determining Cr(VI) by extraction with hydroxyamidines in chloroform over 0.2–0.8 M HCl is described. The molar extinction coefficient of the complexes of Cr(VI) with 10 different hydroxyamidines lie in the range of (1.30– 1.52)×104 l mol−1 cm−1 at λmax 390–400 nm. Of these, the simplest compound, N-hydroxy-N,N′-diphenylbenzamidine (HDPBA) has been chosen for the detailed studies. The limit for detection is 0.1 μg Cr/cm3. The composition of the complex, and the effect of solvents, acids and diverse ions on the extraction of the metal are discussed. The method is free from interference of most of the metal ions except Mn(VII) which is removed by reducing with sodium nitrite. The method has been applied for determination of chromium(VI) to water samples containing the metal at ppb levels.
Mechanism of the Copolymerization of Silicic Acid and Metal Ions in Aqueous Media
Authors: Mizutani Tadashi , Fukushima Yoshiaki , Kamigaito Osami
Published: July 2006

The mechanism of copolymerization of silicic acid and metal ions was found to depend on the magnitude of the hydrolysis constant of the aqua-metal cations. It was also demonstrated that the pH of the solution is the major factor governing the Si/metal ion ratios in the solid phases.
Synthesis and Spectral Properties of 5,5′-Di(4-pyridyl)-2,2′-bithienyl as a New Fluorescent Compound
Authors: Nakajima Riichiro , Iida Hiroyuki , Hara Tadashi
Published: July 2006

A new type of fluorescent compound, 5,5′-di(4-pyridyl)-2,2′-bithienyl, has been synthesized and its fluorescence intensity measured at 510 nm in a 40% aqueous methanol (pH<3.0) with excitation at 425 nm. The quantum yield was found to be 0.52. The thienylpyridine skeleton was found for the first time as a new fluorophore.
One Pot Synthesis of Substituted Tropones from 7,7-Dihalo-2,3-(or 3,4-)epoxybicyclo[4.1.0]heptane Derivatives
Authors: Kato Masahiko , Yamamoto Shigeyuki , Nomura Shigeki , Miwa Toshio
Published: July 2006

In order to obtain a scope and limitations of the reaction for newly developed tropone synthesis, some substituted 2,3- and 3,4-epoxy-7,7-dihalobicyclo[4.1.0]heptanes have been prepared and treated with several acids. We found that (1) the epoxy-carbons of starting materials should have, at least, one substituent which may stabilize the carbenium ion formed by cleavage of the epoxide with acid, (2) as halogens in the starting materials, bromine is superior to chlorine, (3) use of 20 molar equivalent of TFA to a substrate in chloroform at refluxing temperature or use of each 5 molar equivalent of TCA and water to a substrate in toluene at 100°C is recommended.
Photochemical Reaction of (

Remark: Graphics omitted.

) with Ph2C2; Definitive Characterisation of an Insertion Product with a Seven-Membered Metallocyclic Ring
Authors: Grigsby Warren J , Main Lyndsay , Nicholson Brian K
Published: July 2006

The main isolated product from the photochemical reaction of (Remark: Graphics omitted.) with Ph2C2(previously characterised as a η2-acetylene adduct) is shown by an X-ray crystal structure analysis to be (Remark: Graphics omitted.) , formed by insertion of the alkyne into the Mn-C bond.[Crystals are tetragonal, space group I41⁄a, a=30.813(6) Å, c=12.647(5) Å, V=12007(6) Å3, Z=16, R=0.0793 for 1589 reflections with I>3σ(I)].
The Interaction of DNA with Hoechst 33258 Studied by Fluorescence Spectroscopy
Authors: Kubota Yukio
Published: July 2006

The interaction of DNA with the bi-1H-benzimidazole dye Hoechst 33258 at a high molar ratio of DNA phosphate to dye has been studied by means of steady-state and nanosecond time-resolved emission spectroscopy. The spectral shifts and lifetime data, which can be interpreted in terms of the solvent-solute relaxation, are consistent with the existence of two types of bound species. One type, less hydrated bound species, predominates at high ionic strength, whereas the other, more hydrated bound species, occurs at low ionic strength.
Indirect Electrooxidation of Halohydrins by a Double Mediatory System of Ru(VIII)/Ru(IV) and [Cl+]/Cl−. Optimization for the Oxidation of 1,3-Dichloro-2-propanol to 1,3-Dichloroacetone
Authors: Torii Sigeru , Inokuchi Tsutomu , Matsumoto Sigeaki , Saeki Takeaki , Oki Tsunehei
Published: July 2006

Optimum conditions for the electrooxidation of 1,3-dichloro-2-propanol (1) to 1,3-dichloroacetone (2) by using a double redox system of Ru(VIII)/Ru(IV) and [Cl+]/Cl− are elucidated. The electrolysis of 1 in an AcOEt–aqueous NaCl (2:3 v/v) system buffered at pH 2–4 in a divided cell at 0–5°C gives 2 in 98% selectivity toward 1,1,3-trichloroacetone (3) under the current efficiency of 92%.
Raman Spectra and Pressure-Induced Phase Transition of Phenothiazine Crystal
Authors: Araki Gako , Mukai Mikako , Nakayama Hideyuki , Ishii Kikujiro
Published: July 2006

The Raman spectra of the phenothiazine crystal were measured at high pressures up to 20 kbar in a diamond-anvil cell (DAC) at several temperatures. A pressure-induced phase transition was found to occur at 2.2 kbar and 297 K. The high-pressure phase was shown to be the same as the low-temperature ferroelastic phase previously found at atmospheric pressure. The wavenumber of the fluorescence band R1 of ruby, used as the pressure monitor in DAC, was precisely measured to obtain its temperature dependence in the temperature region where the present Raman measurements were carried out.
Accurate Determination of NMR Chemical Shifts in Alkali Halides and Their Correlation with Structural Factors
Authors: Hayashi Shigenobu , Hayamizu Kikuko
Published: July 2006

High-resolution solid-state NMR spectra of alkali halides have been measured using the magic angle spinning (MAS) of the sample, and chemical shifts of 7Li, 23Na, 87Rb, 133Cs, 35Cl, 79Br, and 127I have been determined accurately. The 39K chemical shifts have been determined by NMR without MAS. As the ratio of the cation radius to the anion radius (Rm) increases, the chemical shifts of halogen nuclei show an upfield shift when Rm<0.6, while they show a downfield shift when Rm>0.6. The chemical shifts of the halogen nuclei are explained in terms of the first and the second nearest neighbor interactions, both of which cause a downfield shift. On the other hand, the chemical shifts of alkali nuclei show a downfield shift for the ratio of the anion radius to the cation radius (Rx) less than 1.6, while they show an upfield shift for Rx>1.6. The chemical shifts of the alkali nuclei are expressed by the sum of the nearest neighbor interaction in the absence of the halogen-halogen interaction and the “isolation effect” caused by the halogen-halogen interaction. The “isolation effect” makes the chemical shifts approach to the values of the isolated ions.
Photooxidation of Alkylbenzenes in the Presence of Bromides
Authors: Nakada Masahiro , Fukushi Sachio , Hirota Minoru
Published: July 2006

In the presence of organic bromides, toluene was oxidized photochemically by molecular oxygen, producing benzaldehyde as the major product. A modified procedure using hydrobromic acid and bubbling air also gave benzaldehyde with high efficiency and can be applied for the synthetic purpose. Similarly ethylbenzene gave acetophenone.
Effect of Starting Compositions on the Growth of Calcium Tungstate Crystals from Sodium Tungstate Flux
Authors: Oishi Shuji , Hirao Minoru
Published: July 2006

Experimental evidence for the effect of starting compositions on the growth of CaWO4 crystals from Na2WO4 flux was given on the basis of the obtained solubility data. Crystal growth was conducted by heating mixtures at 1100°C for 5 h, followed by cooling to 500°C at a rate of 5°C h−1. Octahedral crystals up to 4.5 mm in size were grown. Mixture with ΔTSL(=TSoak temperature−TLiquidus temperature)=340°C produced 226 crystals measuring about 2.2 mm on the average. The crystal sizes decreased gradually and crystal numbers increased remarkably with a decrease in ΔTSL. The crystal sizes were mainly determined by the number of crystals grown. The value of ΔTSL played an important role in controlling the size and number of the crystals grown. It was experimentally confirmed that a greater ΔTSL or lower solute content resulted in larger crystals.
Temperature-Programmed Desorption of Dimethylpyridine Adsorbed on Silica–Alumina Prepared by Chemical Vapor Deposition
Authors: Sato Satoshi , Tokumitsu Masahiro , Sodesawa Toshiaki , Nozaki Fumio
Published: July 2006

A temperature-programmed desorption of adsorbed dimethylpyridine clarified the characteristic changes in acid type, acid strength, and acid amount of silica–alumina prepared by depositing silica on an alumina support. Lewis acid sites of the alumina changed into Brønsted acid sites together with a change in the acid strength with increasing silica deposition.
Photofading Reaction of Bis[1-(4-dimethylaminophenyl)-2-phenylethanedithione]nickel(0) in the Presence of N,N′-Dimethylformamide
Authors: Enmanji Koe , Takahashi Kenzou
Published: July 2006

Bis[1-(4-dimethylaminophenyl)-2-phenylethanedithione]nickel(0) was found to undergo photofading in the presence of dimethylformamide, by the action of photogenerated superoxide. Addition of a detergent suppressed the formation of superoxide, with an efficiency paralleling the fatty acid chain length.
Characteristics of Semiconductor and Ion-Sensitive Layers That Affect Response of Ion-Sensing Devices Based on n-SnO2/Ion-Exchange Membrane Junction
Authors: Kimura Keiichi , Kawasaki Yoshiaki , Yokoyama Masaaki
Published: July 2006

The carrier density and thickness of both the semiconductor and ion-sensing membrane were found to significantly affect the sensitivity of ion-sensing devices with a junction of n-type SnO2 and cation-selective plasticized polymeric membranes. When an anion-selective membrane was employed instead, the resulting device responded in a different way from the corresponding cation-sensing device.
Synthesis of 3- and 4-(ω-Phenylalkyl)catechols, the Sap Exuded from a Burmese Lac Tree, Melanorrhoea Usitate
Authors: Miyakoshi Tetsuo , Du Yumin , Kumanotani Ju
Published: July 2006

The presence of 3- and 4-(ω-phenylalkyl)catechols in Burmese lac has been confirmed by their synthesis. 3-(ω-Phenylalkyl)veratroles were synthesized by alkylation of ω-phenylalkyl bromide with aryl lithium derived from veratrole. 4-(ω-Phenylalkyl)veratroles were similarly obtained from ω-phenylalkyl bromide and 4-bromoveratrole. Demethylation of 3- and 4-(ω-phenylalkyl)veratroles with boron tribromide gave the corresponding catechols in good yields.
Crystal Structures of Polymorphic [Fe4(η5-C5H5)4S4](PF6)
Authors: Shimoi Mamoru , Satoh Asako , Ogino Hiroshi
Published: July 2006

[Fe4(η5-C5H5)4S4](PF6) crystals showed polymorphism depending on the recrystallization conditions. Recrystallization from acetonitrile–H2O solution gave monoclinic crystals: C2/c with lattice constants a=18.555(2), b=7.650(1), c=17.850(3) Å, β=96.81(2)°, and Z=4. Recrystallization from N,N dimethylacetamide–ether solution gave tetragonal crystals: I\bar4 with lattice constants a=12.917(2), c=7.637(1) Å, and Z=2. Molecular structures of both crystal systems are almost the same as each other, if the structure for the latter was analyzed assuming that enantiomeric cations are disordered.
Nucleophilic Displacement Catalyzed by Transition Metal. IX. [Pd2(dba)3]·CHCl3–DPPF Catalyzed Cyanation of Aryl Halides and Aryl Triflates
Authors: Takagi Kentaro , Sasaki Ken , Sakakibara Yasumasa
Published: July 2006

A catalyst system comprising [Pd2(dba)3]·CHCl3 and DPPF was proved to be efficient for the cyanation of aryl iodides and aryl triflates with KCN. The reactivities of aryl substrates decreased in the order ArI>ArOTf>ArBr.