bluuebunny/crossref_metadata_2025_split huggingface dataset:
Syntheses of N-Substituted 3,3,4-Triaryl- and 3,3,4,4-Tetraphenyl-2-azetidinones
Authors: Mehrotra Kailash Nath , Singh Surendra Bahadur 
Published: July 2006

Abstract
The reactions of 2-diazo-1,2-diphenylethanone with Schiff’s bases Ar–CH=N–R gave new substituted 2-azetidinones together with 1,1′,4,4′-tetraphenyl-2,2′-azinodiethanone. 2-Diazo-1,2-diphenylethanone reacts with N-benzhydrylidene-N′-phenylurea to give 1-(phenylcarbamoyl)-3,3,4,4-tetraphenyl-2-azetidinone.
Dielectric Relaxation Processes in Some Substituted Amides in Dilute Solutions
Authors: Saxena S K , Shukla J P , Saxena M C 
Published: July 2006

Abstract
The dielectric measurements have been carried out in the microwave region (3.1 cm) over a range of temperatures on propionamide, N-methylpropionamide, N,N-dimethylpropionamide, and N-ethylacetamide. All the molecules except propionamide exhibit high value of distribution parameter. The dielectric dispersion, when resolved by Higasi, Koga, and Nakamura method gives two relaxation times τ(1) and τ(2) widely different from each other, suggesting the two separate processes occurring in the system. The enthalpies for different processes involved have been evaluated by the Eyring equations. The comparison with NMR data of enthalpy to ΔHτ(1), which is related to the process other than molecular, suggests that the rotation of–NR2 group around the carbonyl carbon nitrogen bond is not feasible. The observed result indicates that this may be due to group inversion process. These results are in agreement with the earlier investigations of Saxena et al. on some substituted amides and of Phillips on N,N-dimethylamide using proton resonance spectra. The substituted amides in dilute solution of benzene exhibit some association with the benzene molecules.
Kinetics of the Hydrolysis of Zeolite 4A Surface by the Pressure-jump Relaxation Method
Authors: Ikeda Tetsuya , Sasaki Minoru , Astumian Raymond D , Yasunaga Tatsuya 
Published: July 2006

Abstract
Single relaxation was found in the basic zeolite 4A suspension by the pressure-jump method. The relaxation phenomenon was attributed to the hydrolysis of the zeolite 4A surface and the kinetic parameters were obtained.
Dual-wavelength Spectrophotometric Determination of Trace Amounts of Phosphate in the Presence of Large Amounts of Silicate Using Molybdenum Blue
Authors: Ohashi Kousaburo , Enomoto Toshie , Yamamoto Katsumi 
Published: July 2006

Abstract
A method is described for the determination of trace amounts of phosphate in the presence of large amounts of silicate. It is based on the difference in the absorption spectra of molybdenum blues formed from phosphate and silicate using a dual-wavelength spectrophotometer. The difference in absorbances at 797.3 nm and 825.0 nm is proportional to phosphate concentration over the range 1.60×10−7 to 7.00×10−5 M (1 M=1 mol dm−3).
α-Glucosylation of Phenols with Tetra-O-benzyl-α-d-glucose
Authors: Koto Shinkiti , Morishima Naohiko , Araki Mihoko , Tsuchiya Takuji , Zen Shonosuke 
Published: July 2006

Abstract
An α-glucosylation of phenols with 2,3,4,6-tetra-O-benzyl-α-d-glucopyranose is described. This uses a mixture of p-nitrobenzenesulfonyl chloride, silver trifluoro-methanesulfonate and triethylamine in dichloromethane in a two-stage treatment.
Homogeneous Hydrogenation of α,β-Unsaturated Ketones and Aldehydes Catalyzed by Co2(CO)8–Di(tertiary phosphine) Complexes
Authors: Murata Kazuhisa , Matsuda Akio 
Published: July 2006

Abstract
The cobalt complexes modified by some di(tertiary phosphine)s as ligands were found to be much more active catalysts than Co2(CO)8 for the hydrogenation of α,β-unsaturated ketones and aldehydes under hydroformylation conditions.
The Stability of the Supersaturation State in Optical Resolution by the Preferential Crystallization Procedure
Authors: Hongo Chikara , Yamada Shigeki , Chibata Ichiro 
Published: July 2006

Abstract
In the optical resolution process of Dl-serine m-xylene-4-sulfonate dihydrate by the preferential crystallization procedure, the stability of the supersaturation state of the unseeded isomer was investigated in connection with the cooling conditions. The experiment was initiated with the model solution and was then extended to the actual resolution process. The metastable region of the unseeded isomer on a two-dimensional diagram with the supersaturation degree and cooling time could be divided into the first and the second metastable regions. The limits of the first and the second metastable regions were expressed by a supersaturation degree and by an area on the diagram respectively. Both limiting values were constant, independent of cooling speed and the lowest arrival temperature, if the conditions for the crystallizer, the initial concentration of the Dl-form, the amount of the seed crystals, and the degree of stirring were fixed.
The Prediction of the Optical Resolution Process by the Use of the Preferential Crystallization Procedure
Authors: Hongo Chikara , Yamada Shigeki , Chibata Ichiro 
Published: July 2006

Abstract
In the optical resolution of Dl-serine m-xylene-4-sulfonate dihydrate by the preferential crystallization procedure, the prediction of the resolution process was studied. The solution saturated with the Dl-form at 20 °C was cooled under a programmed cooling pattern and was seeded with the l-isomer. The decrease in the concentration of the l-isomer during the process was predicted by a conventional calculation method. Then, the waiting time for the spontaneous crystallization of the d-isomer was predicted by using the limiting values of the first and the second metastable regions, which were discussed in a previous report. As a result, a good agreement was obtained between the predicted results and the experimental results.
NQR Zeeman Study of Bis(triphenylphosphine)copper(I) Bromide
Authors: Okuda Tsutomu , Hiura Morio , Negita Hisao 
Published: July 2006

Abstract
Zeeman effects of 63Cu and 81Br NQR spectra of bis(triphenylphosphine)copper(I) bromide, CuBr(PPh3)2, have been studied at room temperature. The asymmetry parameters and the quadrupole coupling constants (e2Qq⁄h) have been found to be 0.113 and 64.58 MHz for 63Cu and 0.518 and 105.91 MHz for 81Br. The large asymmetry parameter of the 81Br NQR line is caused by the π-bonding character of the copper-bromine bond. The bonding scheme between the copper and bromine atoms is discussed on the basis of the obtained directions of the electric field gradient axes.
Polarized Absorption and Reflection Spectra of the Single Crystals of 11,11,12,12-Tetracyano-2,6-naphthoquinodimethan (TNAP) Complexes
Authors: Yakushi Kyuya , Sato Yoshiyuki , Ikemoto Isao , Kuroda Haruo 
Published: July 2006

Abstract
The electronic absorption spectra of 2,6-bis(dicyanomethylene)-2,6-dihydronaphthalene (11,11,12,12-tetracyano-2,6-naphthoquinodimethan; TNAP) and its anion radical (TNAP−) were studied. The absorption bands of the solution spectra of TNAP0 and TNAP− were successfully assigned to the electronic transitions which were calculated by the use of molecular orbital method. The polarized absorption and reflection spectra were measured on the single crystals of Na·TNAP and (methyltriphenylphosphonium)(TNAP)2 [(MTPP)(TNAP)2]. The low-lying electronic excitations of these complexes are quite similar to those of the corresponding tetracyano-quinodimethan (TCNQ) salts.
The Structure of the Cyclodextrin Complex. X. Crystal Structure of α-Cyclodextrin-Benzaldehyde (1 : 1) Complex Hexahyderate
Authors: Harata Kazuaki , Uekama Kaneto , Otagiri Masaki , Hirayama Fumitoshi , Ogino Hisashi 
Published: July 2006

Abstract
The crystal structure of the α-cyclodextrin–benzaldehyde (1:1) complex hexahydrate, C36H60O30·C7H6O·6H2O, was determined by the X-ray method. The crystal is monoclinic, the space group being P21 with Z=2. The cell dimensions are a=7.932(1), b=13.500(1), c=24.704(2) Å, and β=90.85(1)°. The structure was solved by means of a Patterson map and a trial-and-error method combined with the rigid-body least-squares technique. Refinement was carried out by the block-diagonal least-squares method to the final R-value of 0.057 for 4565 reflections. α-Cyclodextrin molecules are stacked along the a axis in a head-to-tail fashion to form a channel-type structure. The α-cyclodextrin ring is tilted by an angle of 11.5° against the channel axis. Adjacent α-cyclodextrin molecules along the channel are linked by hydrogen bonds between the primary hydroxyl groups and the secondary hydroxyl groups, and O(2)···water···O(6) hydrogen-bond bridges. The guest benz-aldehyde molecules are aligned inside the α-cyclodextrin column. The benzene ring is inserted into the α-cyclodextrin ring from the secondary hydroxyl side, while the carbonyl group is in the van der Waals contact with the primary hydroxyl side of the next α-cyclodextrin. The guest plane is nearly parallel to the channel axis, making an angle of 71.2° against the plane through six glycosidic oxygen atoms. Spaces between α-cyclodextrin columns are filled with water molecules. Many hydrogen bonds are observed among hydroxyl groups of α-cyclodextrin and water molecules, forming a hydrogen-bond network in the crystal.
On Some Mixed Chelates of Nickel(II) Which Are Highly Volatile, Fusible, and Soluble in Nonpolar Solvents
Authors: Saito Yoko , Takeuchi Toshio , Fukuda Yutaka , Sone Kozo 
Published: July 2006

Abstract
It was found that the mixed chelates of nickel (II) with the general formula [Ni(diam)(β-dik)2], where diam means an N,N- or N,N′-alkylated ethylenediamine and β-dik a β-diketonate anion, are highly volatile, fusible, and often amazingly soluble in nonpolar solvents like CCl4, benzene, or heptane. Representative data on these properties are presented and their correlations with the structures of the ligands are discussed.
Quantitative Interpretation of Infrared Diffuse Reflectance Spectra over Whole Concentration Range
Authors: Hattori Tadashi , Shirai Kenji , Niwa Miki , Murakami Yuichi 
Published: July 2006

Abstract
The infrared diffuse reflectance spectra of CaCO3 dispersed in KBr and Si were measured over a wide concentration range. The relation between relative reflectance and concentration varies with dispersing medium. The relation follows the Kubelka-Munk (K-M) equation only in the low concentration region. The deviation in the high concentration region from the K-M equation changes with wavelength and dispersing medium. The results over the whole concentration range can be interpreted by means of a modified K-M equation in which the difference in the scattering coefficients between the sample and the dispersing medium is taken into account. The tendency of scattering coefficients of CaCO3, KBr, and Si calculated by the modified Kubelka-Munk equation agrees with that of refractive indexes.
Chromatographic Behavior of Metalloporphyrins by Cellulose Thin-layer Chromatography
Authors: Onoue Yoshiaki 
Published: July 2006

Abstract
Cellulose thin-layer chromatographic separation of chlorophyll a, b, and c, pheophytin a, b, and c, Zn(II) and Cu(II)-complexes of protoporphyrin-IX dimethyl ester (PPDE) was studied by using a light petroleum–acetone developing solvent system. The hRf values of metal–PPDE chelates were found to be virtually linearly related with the electronegativities-to-radius ratio (En/ri) of central-metal ions. The hRf values of metalloporphyrins become progressively greater with increase in En/ri values of the central metal. This suggests that a dominant factor influencing the hRf values of metal–porphyrins is the extent of electron transfer from the four nitrogens and/or the π-electron system of porphyrin to central metal.
The Depth Profiling of Glass Surfaces by Mass Spectrometry Using Neutral-particle Bombardment
Authors: Iino Akira , Mizuike Atsushi 
Published: July 2006

Abstract
Glass surfaces are bombarded by energetic neutral argon atoms or oxygen molecules, and the resulting sputtered ions are mass-analyzed. This technique has a higher depth resolution than conventional secondary-ion mass spectrometry. Quantitative depth-concentration profiles of sodium and potassium in the top layer of the surface (within several tens of nanometers of the surface) of Pyrex glass are obtained by the proposed technique.
Kinetic and Equilibrium Studies on the Esterification of Monomeric and μ-Oxo Dimeric Vanadium(V) Complexes with Butyl Alcohols in Chlorobenzene
Authors: Yuchi Akio , Yagishita Yumi , Yamada Shinkichi , Tanaka Motoharu 
Published: July 2006

Abstract
Kinetic and equilibrium studies were made on the esterification of the μ-oxo dimeric vanadium (V) complexes with monoanionic bidentate ligands(HL) such as 8-quinolinol, 5-chloro-8-quinolinol, 5,7-dibromo-8-quinolinol, and 4-isopropyltropolone by butyl alcohols (ROH) in chlorobenzene. The stoichiometry and the rate equation are expressed as follows:
V2O3L4+2ROH\ightleftharpoons2VO(OR)L2+H2O:KDE;
−\fracd[V2O3L4]dt=\frac12×\fracd[VO(OR)L2]dt=(k1+k2[H2O])[V2O3L4][ROH].
The more basic the bound ligand L−, the lower the water-independent rate constant k1 is. For less sterically crowded alcohols, k1 is higher, giving the reactivity order: n-&gt;i-&gt;s-&gt;t-. Water, presumably hydrogen bonded to the terminal oxo group of the complexes, accelerates the esterification(k2 path). The equilibrium constant KDE is linearly correlated with the rate constant k1. The esterification kinetics of the monomeric complex with 2-methyl-8-quinolinol(HL′), which corresponds to the proposed reactive intermediate in the esterification of the μ-oxo dimeric complexes, is also investigated and found the rate equation to be expressed as
−\fracd[VO(OH)L′2]dt=\fracd[VO(OR)L′2]dt=kM,1[VO(OH)L′2[ROH].
k M,1 is 5 times higher than the estimated for the corresponding dimeric complex. Large negative values of ΔS1\eweq and ΔSM,1\eweq point to an associative nucleophilic attack of alcohol to the vanadium center of both dimeric and monomeric complexes. The difference of the reactivity of complexes and alcohols and the detailed mechanism will be discussed.
The Study of Transition-metal Complexes with Ethylenediamine and Cyano Ligands by Means of the X-Ray Photoelectron Spectra
Authors: Sano Mitsuru , Yamatera Hideo 
Published: July 2006

Abstract
The X-ray photoelectron spectra (XPS) were measured in order to obtain the Nls and Cls core-orbital energies of ten ethylenediamine and 21 cyano complexes of transition metals. The difference between the Nls and Cls energies, ΔE, which was found to be hardly affected by the counter ion or by charging, was accurately determined for each complex. The trends observed in the ΔE values for these series of complexes are correlated with the electronic structures of the complexes by the use of Siegbahn’s equation. For the ethylenediamine complexes, the ΔE values are shown to be related to the σ donation. For the cyano complexes, the ΔE values are mainly controlled by the nitrogen charge, which is itself closely connected with the π back-donation. Demonstrative of the importance of the π back-donation are the cases of [Fe(CN)6]4− and [Fe(CN)6]3−, where the decrease in the negative charge from the former to the latter is found to occur dominantly (76%) in the nitrogen atoms. Molecular orbital (MO) calculations in the discrete variational Xα (DV-Xα) scheme were performed for a few series of the cyano complexes, giving results consistent with the XPS results.
Substituent and Solvent Effects in the Reactions of Diaryldiazomethanes with 2,3-Dichloro-5,6-dicyanobenzoquinone
Authors: Oshima Takumi , Nagai Toshikazu 
Published: July 2006

Abstract
Kinetic studies have been made of the reactions of fifteen meta- and para-substituted diphenyldiazomethanes(DDMs) with 2,3-dichloro-5,6-dicyanobenzoquinone(DDQ) in benzene. The second-order rate constants, k, increased with the electron-donability of the substituents, and the value could be correlated with the Yukawa-Tsuno equation: logk⁄k0=−2.33(σ0+0.47Δ\barσR+)+0.017, (r=0.996,30 °C). The ρ value, −2.33, indicates the development of a positive charge at the diazo carbon in the transition state, while the R value, 0.47, confirms the moderate stabilization of the positive charge by the π-electronic contribution of the para substituents. The rate constants have also been determined for the reaction of diphenyldiazomethane(DDM) with DDQ in 28 aprotic solvents. The effects of solvents can be interpreted in terms of the basicity and the steric nature of the solvents. The products of these reactions were poly(2,3-dichloro-5,6-dicyanohydroquinone benzhydryl ether)s, which were easily convertible into benzophenones and α,α-dimethoxydiphenylmethane, together with 2,3-dichloro-5,6-dicyanohydroquinone, under the influence of water and methanol. These solvolysis products were also obtained in excellent yields in the initial presence of these additives.
Specific Catalysis by α-Cyclodextrin on the Dichlorocarbene Attack at Phenolate
Authors: Komiyama Makoto , Hirai Hidefumi 
Published: July 2006

Abstract
A selective attack of dichlorocarbene at the para-position of phenolate has been achieved by using α-cyclo-dextrin and the reaction mechanism has been studied by the 13C-NMR and 1H-NMR spectroscopy. The attack of the carbene at the para-position of phenolate (82%) is dominant over the attack at the ortho-position (18%) in the presence of 0.15 mol dm−3 of α-cyclodextrin, which is in contrast with the predominance of the ortho-attack (59%) over the para-attack (41%) in the absence of α-cyclodextrin.
The Reactions of Phenylmagnesium Halides with Seleninyl Chloride, Diphenyl Selenoxide, and Dibromodiphenylselenium
Authors: Iwama Yasunori , Aragi Masashi , Sugiyama Motohide , Matsui Kasumi , Ishii Yasutaka , Ogawa Masaya 
Published: July 2006

Abstract
Triphenylselenonium halides were readily prepared in good yields by the one-step reaction of seleninyl chloride with phenylmagnesium halides, followed by treatment with hydrogen halides. The yields of triphenylselenonium halides are markedly affected by the molar ratio of seleninyl chloride to the phenylmagnesium halides. In order to interpret the above results, some probable intermediates, such as diphenyl selenoxide, dibromodiphenylselenium, and diphenyl selenide, were investigated by allowing them to react with the phenylmagnesium halides. A pathway which consists of competitive and successive reactions is discussed.
Nucleophilic Cleavage of Phosphate Triesters in Dialkylammonium Bilayer Membranes
Authors: Okahata Yoshio , Ihara Hirotaka , Kunitake Toyoki 
Published: July 2006

Abstract
A study was carried out on the reaction of p-nitrophenyl phosphates with hydroxamate nucleophiles in water in the presence of dialkylammonium bilayer membranes. With ethyl bis(p-nitrophenyl) phosphate, clean second order kinetics was observed for all the hydroxamate nucleophiles, two equivalents of p-nitrophenol being released in most cases. In contrast, a complex kinetics was observed for octadecylbis(p-nitrophenyl)phosphate. The second cleavage process of this long-chain substrate by a long-chain hydroxamate was affected by the fluidity of the matrix membrane, an inflection region being present in the Arrhenius plots near the phase transition temperature(Tc) of the 2C16N+2C1 membrane. The activation energy was 14 and 21 kcal/mol at temperatures above and below Tc, respectively. Similar changes in the activation energy had been observed for decarboxylation and proton abstraction.
Synthesis of [3.3](1,1′)- and [5.5](1,1′)Ruthenocenophanes and Their Ferrocenoruthenocenophane Homologs
Authors: Kamiyama Shin-ichi , Kasahara Akira , Izumi Taeko , Shimizu Iwao , Watabe Hiroyuki 
Published: July 2006

Abstract
[3.3](1,1′)Ruthenocenophane-2,14-diene-1,16-dione, [5.5](1,1′)ruthenocenophane-2,14,17,29-tetraene-1,16-dione and their ferrocenoruthenocenophane homologs were synthesized by using an intermolecular base-catalyzed condensation.
Intramolecular Hydrogen Bonding and Conformations of α,α-Dialkyl- and α-Alkyl-o-methoxybenzyl Alcohols. II. Enthalpies of Hydrogen Bond Formation and Molecular Force Field Calculations on α-Alkyl-substituted Benzyl Alcohols
Authors: Ito Masayuki , Hirota Minoru 
Published: July 2006

Abstract
Enthalpies of intramolecular hydrogen bond formation (ΔH) were determined for a series of α-mono- and α,α-dialkyl-o-methoxybenzyl alcohols and related compounds. The −ΔH values of the unsubstituted and α,α-dialkyl-o-methoxybenzyl alcohols are more than 2.5 kJ mol−1, while those for the corresponding α-monoalkyl derivatives are at most 1 kJ mol−1. This tendency is in accordance with the results on their ΔvOH and εb/εf values, showing the hydrogen bonded conformations of the α-monoalkyl derivatives are less favorable than those of the other alcohols in discussion. Molecular force field calculations on α-alkyl- and α,α-dialkylbenzyl alcohols were also carried out. The results shows that the hydroxyl/aryl coplanar conformation (ω=0°) is the most stable for the unsubstituted and α,α-dialkylbenzyl alcohols and the hydroxyl/aryl non-coplanar conformation (ω=30°) for α-alkylbenzyl alcohols. Since the OH···O distance might be farther and, hence, the overlap between the unshared electron pairs on the methoxyl oxygen and the anti-bonding OH orbital might be less in the non-coplanar conformation, α-monoalkyl-o-methoxybenzyl alcohols are less favorable than the corresponding α,α-dialkyl derivatives in the intramolecular hydrogen bond formation.
Improvement of Furan Yield in Oxidation of Crotonaldehyde by Modifying 12-Molybdophosphoric Acid Catalysts
Authors: Tsai Tian-hsi , Ai Mamoru , Ozaki Atsumu 
Published: July 2006

Abstract
12-Molybdophosphoric acid effective for oxidation of crotonaldehyde to furan was modified in two ways; by adding various cations and by replacing Mo with V or W. Among cations caesium was proved to be most effective in improving the furan yield, by decreasing reactivity of product furan relative to crotonaldehyde, thus minimizing the secondary oxidation of furan to maleic anhydride. The highest efficiency of caesium is associated with its high basicity, while the active catalyst species responsible for the furan formation is acidic in nature. The replacement of Mo by V or W gave rise to decreased activity, in contrast to other oxidations on the same catalyst. The unique character of crotonaldehyde oxidation is discussed.
Electrochemical Oxidation-Reduction Properties of Covalently Bound FAD of Cholesterol Oxidase Adsorbed on Mercury Electrode Surface
Authors: Ikeda Tokuji , Ando Shinji , Senda Mitsugi 
Published: July 2006

Abstract
Cholesterol oxidase from Schizophyllum commune was studied by cyclic d.c. and a.c. voltammetry with a hanging mercury drop electrode. The enzyme gave d.c. and a.c. waves due to covalently bound FAD of the enzyme adsorbed on an electrode surface. The waves were interpreted in terms of d.c. and a.c. voltammetry of a twostep surface redox reaction. The standard surface oxidation-reduction potential of the enzyme adsorbed on the electrode surface, Es′, was −0.325 V vs. SCE, the semiquinone formation constant being 1.5±1.0 at pH 7.4 (25 °C). The pH dependence of Es′ was −60 mV/pH (pH 2.0–6.4), −30 mV/pH (pH 6.4–8.5), and −60 mV/pH (pH 8.5–12.0). The apparent charge transfer rate constant of the surface redox reaction was 1.6±0.5×103 s−1 at pH 5.4.
Dimeric Copper(II) Nitrato and Chloro Complexes with N-(3-Dimethylaminopropyl)salicylideneaminato Ligand Protonated at the Terminal Nitrogen
Authors: Tokii Tadashi , Tenhiro Toshihiko , Muto Yoneichiro 
Published: July 2006

Abstract
The title complexes have been prepared and characterized. The strong antiferromagnetic interaction observed for the complexes is interpreted in terms of a phenolic-oxygen-bridged dimeric structure with the metal ions in a square-pyramidal geometry.