bluuebunny/crossref_metadata_2025_split huggingface dataset:
Yields of Excited Triplet Products Generated from the Air Oxidation of 3-Methyl-2-butanone and Isopropyl Phenyl Ketone in a Dimethyl Sulfoxide Solution Containing Potassium t-Butoxide
Authors: Kamiya Isao 
Published: July 2006

Abstract
An attempt has been made to evolve the kinetic scheme in order to evaluate the yields (φreact*) of excited triplet products generated from the air oxidation of 3-methyl-2-butanone (1) and isopropyl phenyl ketone (2). Expressions for the total light emission and quantum yield of the indirect chemiluminescence (CL) can be derived, from which the rates of energy transfer from excited triplet products to singlet 9,10-dibromoanthracene (DBA), kTS, and φreact* were determined on the basis of the CL intensity measured for various DBA concentrations. The values of kTS from 1 and 2 (4×108 and 1×109 1 mol−1 s−1) are in fair agreement with the values proposed by several investigators who measured the indirect CL from the thermal cleavage of 1,2-dioxetanes. The markedly small φreact* values (1×10−5 and 1×10−3) result from the fact that the CL arises from a minor reaction.
Cobalt(III) Complexes Containing Large Chelate Rings. II. Syntheses and Properties of Cobalt(III)–Ammine Complexes Containing α,ω-Alkanediamines
Authors: Ogino Hiroshi 
Published: July 2006

Abstract
Reactions of [Co(H2O)(NH3)5](ClO4)3 with H2N(CH2)nNH2 (N–N) in dimethyl sulfoxide were examined by changing the number of methylene groups in N–N (n=2–5, 7, 8, 10, 12, and 14). Complexes of the Co(NH3)4(N–N)3+ type were found to be formed for n=2–4, 12, and 14, but, not for n=5, 7, 8, and 10. In addition to these products, a number of new cobalt(III) complexes were isolated.
The Crystal Structure and Magnetic Property of Di-μ-propionato-O,O′-bis[N-p-tolylsalicylideneaminatocopper(II)]
Authors: Mikuriya Masahiro , Kida Sigeo , Ueda Ikuhiko , Tokii Tadashi , Muto Yoneichiro 
Published: July 2006

Abstract
The crystal structure of di-μ-propionato-O,O′-bis[N-p-tolylsalicylideneaminatocopper(II)] was determined by X-ray diffraction method using the data collected by counter diffractometer techniques. The space group is P\bar1 and the cell constants are a=12.565(2), b=13.040(2), c=12.230(2) Å, α=107.73(1), β=115.72(1), γ=100.18(1)°, and Z=2. The structure was solved by the heavy atom method and refined by the block-diagonal leastsquares method to an R factor of 0.029. The crystal is composed of one-dimensional chains extended along the c axis, where the two copper atoms coordinated by the Schiff bases are bridged by two propionate groups. The magnetic property was discussed on the basis of the crystal structure.
Adsorption of Phosphate on Synthetic Silica–Alumina Possessing Lewis-acid Sites
Authors: Takimoto Kazuto , Fujita Akira , Tsuda Satoru 
Published: July 2006

Abstract
It was confirmed from measurements of the adsorption isotherms of phosphates in aqueous solutions that there were adsorption sites with very high reactivity on the surface of silica–alumina. The concentration of adsorption sites which is estimated from the adsorption amount extrapolated to zero equilibrium concentration is nearly twice the concentration of Lewis-acid sites for silica–alumina of higher alumina content. Furthermore, the concentration of phosphate adsorbed on the surface of various silica–alumina is relatively well correlated with the concentration of Lewis-acid sites.
Dye-sensitization on the Photocurrent at Zinc Oxide Electrode in Aqueous Electrolyte Solution
Authors: Matsumura Michio , Nomura Yoichi , Tsubomura Hiroshi 
Published: July 2006

Abstract
The dye-sensitized photocurrents generated from the electrochemical systems &lt;zinc oxide|aq solution|platinum&gt; have been studied. The action spectra for the photocurrent, its dependence on the concentration of the dye solution and other experimental results have revealed that the photocurrent is caused by the dye adsorbed on the electrode, not from that dissolved in the liquid phase. From the analysis of the decay of the photocurrent with the time of illumination, the quantum yield for the electron injection from the excited dye has been determined. Rose Bengal showed the quantum yield of 22%. The influence of halide ions on the photocurrent has also been studied.
The Molecular Structure of Dimethyl Sulfide
Authors: Iijima Takao , Tsuchiya Shuzo , Kimura Masao 
Published: July 2006

Abstract
The gas-phase molecular structure of dimethyl sulfide, (CH3)2S, has been investigated by means of electron diffraction. By a joint analysis of the diffraction results and the spectroscopic moments of inertia by Pierce and Hayashi, the structure parameters, the distances in rg and the angles in \varphiav, were determined (with parenthesized limits of error) to be as follows: S–C=1.807(2) Å, C–H=1.116(3) Å, ∠CSC=99.05(4)°, and ∠HCH=109.3(5)°. A tilt of 2.35° and the local C3v symmetry of the methyl groups were assumed. The isotope effects of deuterium substitution were examined, and the DCD angle was found to be larger than HCH in the zero-point average structure.
The Oxidation Activity and Acid-base Properties of V2O5-based Binary Catalysts
Authors: Ai Mamoru 
Published: July 2006

Abstract
The oxidation of cis-2-butene, butadiene, and acetic acid was carried out by using a series of V2O5–XnOm (atomic ratio=9 : 1) catalysts with more than twenty metal oxides (XnOm). The results were compared with the dehydration activity for isopropyl alcohol (IPA), as a measure of acidity, and with the ratio, dehydrogenation activity for IPA/dehydration activity for IPA, used as a measure of the basicity of catalyst. The activity for the oxidation of butadiene and that for the isomerization of butene are correlated with the acidity, and the activity for the oxidation of acetic acid with the basicity of the catalyst. The selectivity to maleic anhydride from butene and butadiene is scarcely influenced by the introduction of metal oxides. Butene is mainly oxidized to acetic acid as a result of C–C fission. The selectivity to acetic acid is enhanced when the catalyst is highly acidic, decreasing with increase in basicity. It is concluded that the introduction of metal oxides into V2O5 modifies the acid-base properties of the catalyst, inducing a change in oxidation activity and selectivity.
Structure of Aqueous Isomeric Butyl Alcohols—Sound Velocity Studies
Authors: Murthy N Manohara , Subrahmanyam S V 
Published: July 2006

Abstract
The effect of isomeric butyl alcohols on the temperature of sound velocity maximum in water (TSVM) was studied using a variable path interferometer working at 3 MHz. The structural contribution to the shift in TSVM, [ΔTstr]exp was evaluated for the butyl alcohols and the results are compared with those obtained from studies on the effect of these solutes on the temperature of adiabatic compressibility minimum and density maximum of water. The results indicate that the butyl alcohols enhance the hydrogen-bonded structure of water at low concentrations and at any given concentration, the order of increasing structural contribution to the shift in TSVM being t-butyl&gt;s-butyl&gt;isobutyl&gt;butyl alcohols. The structural propensities of the butyl alcohols as revealed by TSVM studies are in line with the information obtained from the temperature of adiabatic compressibility minimum and density maximum studies. The results of the present study indicate that TSVM studies are useful in understanding the solution structure in aqueous mixtures.
The Synthesis of Greigite from a Polysulfide Solution at about 100 °C
Authors: Wada Hiroaki 
Published: July 2006

Abstract
Favorable synthesis conditions for greigite are examined in FeSO4·(NH4)2SO4–Na2S–Na2Sx systems at about 100 °C. It has been found that greigite formation is influenced by the pH adjustment and by the addition of sulfur. When the final pH is about 6.0 and the dissolved iron concentration is in the 10−3–10−1.5 M range, greigite is synthesized as a single phase. The unit-cell dimensions of greigite range from 9.840 to 9.877 Å, corresponding to variations in compositions between 45.4 and 42.9 atomic % Fe. The formula of synthetic greigite is represented as Fe3+xS4 (x=0–0.4).
One-dimensional System of Square-planar Bis(1,2-dicyanovinylene-1,2-dithiolato)metal Complexes. I. The Crystal Structure of [(C4H9)4N]2[Ni(mnt)2] and [(C2H5)4N][Ni(mnt)2]
Authors: Kobayashi Akiko , Sasaki Yukiyoshi 
Published: July 2006

Abstract
X-Ray crystal structure analyses of [(C4H9)4N]2[Ni(mnt)2] (I) and [(C2H5)4N][Ni(mnt)2] (II) {mnt: 1,2-dicyanovinylene-1,2-dithiolato C4N2S22−} have been carried out from the viewpoint of one-dimensional system. Crystals of (I) belong to triclinic system: a=12.360(6), b=11.138(12), c=9.833(9) Å, α=118.43(9), β=92.05(6), γ=91.91(6)°, space group P\bar1 with Z=1. The compound (II) forms monoclinic crystals, P21/a: a=20.018(18), b=16.079(9), c=7.118(6) Å, β=110.43(6)°, Z=4. Both structures, solved by the heavy-atom method, have been refined anisotropically by least-squares procedure to R=0.049 and 0.050 for (I) and (II), respectively. The bond distances of diamagnetic Ni(mnt)22− anion and paramagnetic Ni(mnt)21− anion are compared. A columnar structure was found in the structure of (II). The Ni(mnt)21− ions form a diadic unit, that is a repeating unit of two anions, within the columns. The electrical conductivity data are measured along the direction parallel to the Ni(mnt)21− stacks in the temperature range from room temperature to 373 K. This compound behaves as a semiconductor in this temperature range.
The Study of Thermochemical Hydrogen Preparation. III. An Oxygen-evolving Step through the Thermal Splitting of Sulfuric Acid
Authors: Dokiya Masayuki , Kameyama Tetsuya , Fukuda Kenzo , Kotera Yoshihide 
Published: July 2006

Abstract
The thermal decomposition of sulfuric acid is used as a step in the oxygen evolution in some thermochemical water-splitting cycles. The catalytic activity of metal oxides was studied in an attempt to find some suitable catalysts for sulfuric acid decomposition. The catalytic activity of SiO2, Al2O3, ZnO, CuO, NiO, CoO, Fe2O3, MnO, Cr2O3, V2O5, TiO2 was measured at high temperatures (800–870 °C and at atmospheric pressure. Iron(III) oxide was found to have the highest activity as a catalyst. Low catalytic activity was observed for the oxides (Al2O3, ZnO, NiO, CoO, MnO) which change to their sulfates under the present reaction conditions. Since the reaction conditions were very severe (more than 800 °C and in the presence of steam), a rapid decrease in both the specific surface area and the catalytic activity was observed. In order to avoid these disadvantages and in order to prepare practically useful catalysts, iron(III) oxide was pelletized and sintered (1000 °C, 6 h). Upon this procedure, this catalyst showed an almost constant activity for 120 hours’ reaction.
Synthesis and Absorption Spectra of the [Co(O–O)2(py)2]-type Complexes
Authors: Ida Yayoi , Fujinami Shuhei , Shibata Muraji 
Published: July 2006

Abstract
Five bis (dicarboxylato)bis(pyridine)-type complexes, trans-[CoCO3ox(py)2]−, trans- and cis-[Co(ox)2(py)2]−, and trans- and cis-[Co(mal)2(py)2]−, have been isolated as crystals and characterized on the basis of the absorption spectra, the PMR spectra, etc. The trans isomers of the carbonatooxalato and bis(oxalato) complexes reveal spectra similar to that of the trans-[Co(CO3)2(py)2] complex synthesized previously; the splittings of the absorption bands are not observed in the I bands, but are observed in the II bands. On the other hand, the trans isomer of the bis(malonato) complex reveals no splittings in either the I band or the II band. The assignment of these absorption bands has been made from considerations based on the Angular Overlap Model.
Association Constants of Optically Active [Co(en)3]3+ with (+)-Tartrate and Fumarate Ions Determined from the Kinetic Data of Hydrogen-Deuterium Exchange
Authors: Fujita Miho , Yamatera Hideo 
Published: July 2006

Abstract
The hydrogen-deuterium exchange rates of Λ- and Δ-[Co(en)3]3+ were measured in D2O solutions containing (+)-tartrate ions. From the kinetic data, the ion-association constants of the Λ- and Δ-isomers with (+)-tartrate ions were determined to be 40 and 32 (I=0.1) respectively. Similar measurements with fumarate resulted in the association constant of 16 (I=0.1).
The Synthesis of Peptides by Means of Proteolytic Enzymes
Authors: Isowa Yoshikazu , Ohmori Muneki , Ichikawa Tetsuya , Kurita Hideaki , Sato Masanari , Mori Kaoru 
Published: July 2006

Abstract
Nagarse, papain, pepsin and thermolysin were found to catalyze the peptide bond formation between two amino acids or peptides, one protected with a suitable group at the amino group and the other at the carboxyl group. Experiments with various combinations of amino acids and dipeptides show specificity in the catalytic action in varying degree which depending on the nature of the enzyme. Since the condensation takes place efficiently under mild conditions, this method opens up a useful way for the synthesis of peptides.
The Enzymatic Synthesis of Protected Valine-5 Angiotensin II Amide-1
Authors: Isowa Yoshikazu , Ohmori Muneki , Sato Masanari , Mori Kaoru 
Published: July 2006

Abstract
An example of the use of proteolytic enzymes to facilitate the peptide synthesis by fragment condensation is provided for the preparation of protected valine-5 angiotensin II amide-1 using t-butoxycarbonylpeptides as a carboxyl component and a peptide ethyl ester as an amine component. The proteolytic enzymes used are papain, nagarse (subtilisin BPN′) and microbial metalloenzyme isolated from St. caespitosus. Papain-catalyzed condensation reaction afforded the corresponding oligopeptide in the ester form, whereas nagarse and microbial metalloenzyme-catalyzed condensation reactions afforded the products in the carboxyl free form. Assignment of the product was made on the basis of a comparison of physical properties with those of the peptide prepared by the solution method.
OH− as a Possible Cause of the Electron-donor Property of the ZrO2–TiO2 System
Authors: Esumi Kunio , Shimada Hiroaki , Meguro Kenjiro 
Published: July 2006

Abstract
The electron-donor property of the zirconia-titania system was investigated by means of the adsorption of TCNQ. The TCNQ anion radicals were formed as a result of electron transfer to adsorbed TCNQ from the zirconia-titania surface. The radical concentration on the zirconia-titania system decreased with a increase in the titania content, reached a minimum point at a titania content of 38%, and then increased with the further increase in the titania content. This behavior can explained by the relative amount of OH− sites, which must be proportional to both, or either one, the relative contents of the pure zirconia phase or the pure titania phase existing on the surface of the zirconia-titania system.
The Synthesis of 3-Substituted Tropilidenes by the Dehydration of 1-Substituted 2,6-CycloheptadienoIs. A New Unambiguous Route
Authors: Takeuchi Ken’ichi , Maeda Takashi , Okamoto Kunio 
Published: July 2006

Abstract
3-Alkyl-, 3-aryl-, and 3-deuteriotropilidenes are prepared in 21–29% yields by the dehydration of the corresponding 1-substituted 2,6-cycloheptadienols with boric acid. The present method provides an unambiguous route to the title compounds.
The Effects of Solvents on the Electronic Absorption Spectrum of Sodium 4-Nitrophenoxide in the Presence of 15-Crown-5 Ether
Authors: Ueji Shinichi , Kitadani Masayuki 
Published: July 2006

Abstract
The electronic absorption spectrum of sodium 4-nitrophenoxide was determined in 21 solvents of varying polarities by the aid of the ability of 15-crown-5 ether to solubilize the salt in nonpolar solvents. These spectra showed a marked difference between hydroxylic solvents and nonhydroxylic solvents. A possible interpretation for this difference is presented.
The Interaction of Acridine Orange with Poly(S-carboxymethyl-l-cysteine)
Authors: Imae Toyoko , Ikeda Shoichi 
Published: July 2006

Abstract
The interaction of Acridine Orange with poly(S-carboxymethyl-l-cysteine) has been investigated by observing the solubility behavior, absorption spectra, and circular dichroism of the mixture. When the dye is added to aqueous solution of the polymer, the mixture is homogeneous at higher pH, but precipitation takes place at lower pH; the threshold pH ranges from 3.5 to 6, depending on the mixing ratio. For [P]/[D] 1 or less, the mixture is again homogeneous at very low pH between 4 and 2, when no salt is added. Various type of circular dichroism are induced for the homogeneous solutions, which are characteristic of the bound dye species on the polymer and the structure of dye–polymer complex. The binding of dye with the polymer is mainly caused by electrostatic effect, and the solubility of the mixture is interpreted by considering the ionization of polymer and the binding of dye to the polymer.
PMR Studies of the Phase Transition in N,N,N′,N′-Tetramethyl-p-phenylenediamine (Wurster’s Blue) Perchlorate
Authors: Inoue Motomichi , Kuramoto Hiroyoshi , Nakamura Daiyu 
Published: July 2006

Abstract
The powder PMR spectra of [TMPD]+(ClO4)− were recorded in the temperature range 110–300 K. The spectra observed above 140 K consist of two widely separated simple absorption curves of intensity ratio approximately equal to 3 : 1. Spin densities on the carbon and nitrogen atoms of the cation radical were evaluated from the observed field shift ascribable to the Fermi contact interaction. The spin density distribution of the radical ion changes at the transition temperature of 189 K.
Reactions of Benzyne–Silver Cation Complex with Substituted Benzenes
Authors: Tabushi Iwao , Yamada Hidenori , Yoshida Zenichi , Oda Ryohei 
Published: July 2006

Abstract
The presence of silver perchlorate changed the products in the reaction of benzyne with substituted benzene (anisole, toluene, chlorobenzene or methyl benzoate) to increase biphenyl and/or benzylidyne trifluoride derivatives by the sacrifice of benzobicyclo[2.2.2]octatriene derivatives. In the case of toluene, o-methylbiphenyl (15) and 6-methylbenzocyclooctene (14) were considered to be formed via common intermediate. These results were well explained by an assumption of benzyne–silver cation complex. From competition experiments, it was concluded that benzyne-silver cation complex assumed here had a stronger electrophilicity than benzyne itself.
Linear-sweep Voltammetry and the Simultaneous Determination of Purine Bases and Their Nucleosides in the Glassy Carbon Electrode
Authors: Yao Toshio , Wasa Tamotsu , Musha Soichiro 
Published: July 2006

Abstract
Adenine, adenosine, guanine, and guanosine were voltammetrically oxidized in a glassy carbon electrode in aqueous solutions, but at different potentials. In general, the nucleosides were oxidized at more positive potentials than their bases. The bases and their nucleosides were strongly adsorbed on the surface of the glassy carbon electrode at the pH values around neutrality, so that the concentration vs. anodic peak current curves were not linear. The adsorption on the electrode was very dependent on the pH, and at pH values below 4 good linear relationships were observed between the anodic peak current and the concentration. The differences between the peak potentials of each of the purine bases and their nucleosides were most pronounced at pH 2–4. Consequently, it was possible to determine simultaneously both in mixtures of the purine bases and their nucleosides by using Britton-Robinson buffer as a supporting electrolyte in the pH range of 2–4. The proposed method is simple and rapid, since no prior treatment or separation procedure is required.
Reaction of Ru(II)-EDTA in Sodium Formate–Formic Acid Solutions
Authors: Shimizu Kunio 
Published: July 2006

Abstract
When [RuIII(Hedta)(H2O)] was reduced at mercury electrode in sodium formate–formic acid solutions, the reduced species gradually became polarographically inactive. The final product of the deactivation reaction was isolated and identified as Na2[RuII(edta)(CO)]. The kinetics follows the second-order rate equation, −dc1⁄dt=kobsd c1 c2, where c1=[[RuII(Hedta)(H2O)]−]+[[RuII(edta)(H2O)]2−] and c2=[HCOO−]+[HCOOH]. The kobsd value was found to be expressed by k [H+]/(KA+[H+]), where KA (=3.28×10−4 mol dm−3) and KR (=6.92×10−4 mol dm−3) are the acid-dissociation constants of formic acid and [RuII(Hedta)(H2O)]−, respectively, with k=1.01×10−5 s−1 at 25 °C (ionic strength=0.5 mol dm−3). Several possible mechanisms for the reaction were discussed. Probably the reaction proceeds through the formation of an intermediate involving one formate anion followed by dehydration and rearrangement.
Restricted Rotation Involving the Tetrahedral Carbon. XX. Barriers to Rotation and 13C NMR Spectra of 9-(2-Alkylphenyl)fluorene Derivatives
Authors: Nakamura Mikio , Nakamura Nobuo , Oki Michinori 
Published: July 2006

Abstract
A series of 9-(2-alkylphenyl)fluorene derivatives are prepared and their internal rotation about the C9–Car bond is examined. Those which have a methyl, an ethyl, or an isopropyl group in 2′ position exist as a mixture of sp and ap forms, showing coalescence phenomena in the NMR spectra at high temperatures. The barriers to rotation of these compounds are obtained by the usual DNMR method. 9-(2-t-Butylphenyl)fluorene, in contrast, is found to exsist exclusively as an sp form and thus the barrier to rotation must be determined by measuring the rates of conversion from the unstable ap form which is successfully obtained by the protonation of the corresponding lithium fluorenide at low temperatures. The barriers to rotation of the compounds are alike except for the t-butyl compound. The difference is explained in terms of the conformation of the alkyl group in the ground and the transition state for rotation. The 13C NMR data also exhibit a large steric interaction between the alkyl group and the fluorene ring.
The Photosensitized Oxygenation of Furanoeremophilanes. II. The Preparation and Stereochemistry of the Isomeric Hydroperoxides and the Corresponding Lactones from Furanofukinin and Furanoeremophilane
Authors: Naya Keizo , Nogi Noboru , Makiyama Yasuo , Takashina Hideo , Imagawa Takashi 
Published: July 2006

Abstract
The dye-sensitized oxygenation of furanofukinin, and furanoeremophilane, in methanol gave, quantitatively, crystalline mixtures of two isomeric hydroperoxides each consisting of a pair of 8α-methoxy-12β-hydroperoxy and 8β-methoxy-12α-hydroperoxy derivatives respectively. The hydroperoxides were readily transformed to the corresponding lactones with acetic anhydride-pyridine through dehydration. The stereochemistry of the hydroperoxides and the corresponding lactones has been elucidated by spectral and chemical methods according to a previously outlined generalization. Further, furanofukinin, furanoeremophilane, and 8β-hydroxyeremophilenolide, have been synthesized from petasalbin, fukinone, and an epimeric mixture of 8α- and 8β-methoxy lactones, respectively.
The Ethylation of Nucleic Acid-Bases with Triethyl Phosphate
Authors: Tanabe Toshizumi , Yamauchi Kiyoshi , Kinoshita Masayoshi 
Published: July 2006

Abstract
Uracil, thymine, cytosine, adenine, and guanine were alkylated by triethyl phosphate in a homogeneous aqueous phase at 60–80 °C, giving the corresponding ethyl derivatives in considerable yields. The reactivity order on the ethylating site in each base was found to be as follows; uracil, thymine, and cytosine: N-1&gt;N-3; adenine: N-9≈N-3&gt;N-7, N-1; guanine: N-1&gt;N-7&gt;N-3, N-9.
Colloid Titration Behavior of the Maleic Acid–Methyl Vinyl Ether Copolymer
Authors: Kokufuta Etsuo , Iwai Shinji 
Published: July 2006

Abstract
The colloid titration of the maleic acid–methyl vinyl ether (MA–MVE) copolymer with trimethylammonium glycol chitosan iodide (MGCH) was carried out at various pH values. The mechanism of the formation of the polyion complex between the MA–MVE copolymer and the MGCH ions was discussed.