bluuebunny/crossref_metadata_2025_split huggingface dataset:
Rapid Solvent Extraction and Direct Spectrophotometric Determination of Lead(II) with 1,1,1-Trifluoro-4-(2-thienyl)-4-mercaptobut-3-en-2-one
Authors: Akki S B , Khopkar S M 
Published: July 2006

Abstract
The thio derivative of 2-thenoyltrifluoroacetone 1,1,1-trifluoro-4-(2-thienyl)-4-mercaptobut-3-en-2-one (STTA) is used for the simultaneous extraction and direct colorimetric determination of lead. About 100 μg of lead is quantitatively extracted, at pH 6.5, with 10 ml of 0.0020m STTA-CCl4 as a bright orange colored complex, which can be measured spectrophotometrically at 480 nm. The system conforms to Beer’s law over the concentration range of 1–40 μ/ml of lead(II). The color of the complex is stable for 60 hr. Lead can be quantitatively extracted and determined in the presence of a number of ions. The method is made selective by using some sequestering agents and carrying out selective extractions with mesityl oxide. The procedure is found to be suitable for the analysis of lead in gun metal and solder.
Dielectric Dispersion at Meter Waves of 1-Hexanol and 1-Octanol in Cyclohexane Solutions
Authors: Komooka Hitoshi 
Published: July 2006

Abstract
The dielectric constants and losses of 1-hexanol and 1-octanol in cyclohexane solutions were measured in the frequency range 60–480 MHz at various temperatures. The values ε0−ε∞ deviate widely from the linear dependence on concentration. The curve of (ε0−ε∞)⁄c plotted against concentration c falls rapidly as c decreases. Its value seems to be zero at the concentration of 1 mol/l. A comparison with the values of higher alcohols given in literature shows that the curve is almost uniquely determined for each temperature as a function of the concentration of hydroxyl group alone, irrespective of the length of C–C chain in alkyl group of alcohols. As shown by Ibbitson and Moore, there exist considerable amounts of dimers, trimers and cyclic polymers in the dilute solutions of 1% by weight. The cause for the large values of dielectric constant cannot be merely attributed to the formation of hydrogen-bonded aggregates of molecules. A possible structure of the aggregates is discussed.
The Dissolution of Olivine in Aqueous Solutions of Inorganic Acids
Authors: Sanemasa Isao , Yoshida Minoru , Ozawa Takejiro 
Published: July 2006

Abstract
The dissolution of olivine was studied in aqueous solutions of inorganic acids at temperatures of 35, 50, and 65°C in order to obtain basic information about the alteration and leaching processes in acid hot spring regions. The rates of dissolution have been determined by measuring the change in the concentrations of silica, magnesium, and the total iron leached in the solutions as a function of the time. Olivine dissolved in stirred aqueous solutions of 0.05–2n perchloric, hydrochloric, and sulphuric acids without any selective dissolution of components in the mineral. The rate at which olivine dissolved was found to be two-thirds of the reaction order with respect to the sample-powder (10–20 μ in diameter) weight (i.e., first order with respect to the surface area) and to decrease in the order of H2SO4&gt;&gt;HCl&gt;HClO4. HSO4− enchanced the rate remarkably. The complexing affinity of the anions did not play an important part in the reaction with olivine powder.
The Crystal Structure of (−)589-Dinitrobis(ethylenediamine)cobalt(III) (+)589-Bis(malonato)ethylenediaminecobaltate(III)
Authors: Matsumoto Keiji , Kuroya Hisao 
Published: July 2006

Abstract
The crystal structure of (−)589-[Co(NO2)2en2] (+)589-[Co mal2 en] has been investigated by the X-ray method. Crystal data: triclinic, space group P1; a=10.58(2)Å, b=7.98(1)Å, c=7.99(1)Å, α=122.8(2)°, β=105.3(2)°, γ=74.6(2)°; Z=1. The crystal structure was determined by the Fourier technique and was refined by the leastsquares method to an R factor of 0.101. The Δ configuration has been assigned to both the complex cation and anion, (−)589-[Co(NO2)2en2]+ and (+)589-[Co mal2en]−. The two Co-mal chelate rings are nearly planar. The O–Co–O angle in this ring is 96°, slightly larger than the N–Co–N angle observed in the cobalt(III)-trimethylenediamine chelate ring. All the ethylenediamine ligands in the two complex ions have the ob-conformation.
Binuclear Metal Complexes. III. Preparation and Properties of Mononuclear and Binuclear Copper(II) and Nickel(II) Complexes of New Macrocycles and Their Related Ligands
Authors: Okawa Hisashi , Kida Sigeo 
Published: July 2006

Abstract
The syntheses and properties of copper(II) and nickel(II) complexes of N,N′-alkylenebis(3-formyl-5-methylsalicylaldimine (alkylene=ethylene, propylene, or trimethylene) are described. By the reaction of these complexes with other alkylenediamines (ethylenediamine or trimethylenediamine), mononuclear copper(II) and nickel(II) complexes of new N4O2-type macrocycles have been synthesized. These complexes react with additional copper(II) or nickel(II) ions to form binuclear copper(II) or nickel(II) complexes. The geometries and properties of these new complexes are discussed.
Propiolamidines I. Syntheses of N,N′-Disubstituted Phenylpropiolamidines and New Routes to 5-N-Substituted Amino-3-phenylisoxazoles and 5-N-Substituted Amino-1,3-diphenylpyrazoles
Authors: Fujita Hiroshi , Endo Rokuro , Aoyama Akira , Ichii Takeshi 
Published: July 2006

Abstract
N,N′-Disubstituted phenylpropiolamidines were synthesized from phenylacetylene and carbodiimides. They were inert toward nucleophiles in a neutral or basic medium, but reactive in an acidic one. They reacted in the presence of hydrogen chloride with hydroxylamine, hydrazine, and arylhydrazines to give 5-N-substituted amino-3-phenylisoxazoles, 5-N-substituted amino-3-phenylpyrazole and 5-N-substituted amino-1-aryl-3-phenylpyrazoles, respectively, by nucleophilic addition followed by cyclization. The reaction mechanism is discussed on the basis of the structures of these heterocyclic compounds.
The Analytical Application of Sulfur Analogues of β-Diketones. I. The Extraction Spectrophotometric Determination of Cobalt(II) with 1,1,1-trifluoro-4-(2-thienyl)-4-mercaptobut-3-en-2-one (STTA)
Authors: Honjyo Takaharu , Kiba Toshiyasu 
Published: July 2006

Abstract
The solvent extraction of cobalt(II) with 1,1,1-trifluoro-4-(2-thienyl)-4-mercaptobut-3-en-2-one (abbreviated as STTA) in cyclohexane has been investigated, and a new spectrophotometric method for the determination of minute amounts of cobalt has been developed on the basis of the results obtained in the extraction study. When a sample solution the pH of which had been adjusted to 6.0–6.5 with hydrochloric acid or sodium hydroxide solution was shaken with a 10−3m STTA organic solution, the extraction of cobalt(II) proceeded rapidly and quantitatively. The amount of cobalt up to 8 ppm in the final organic phase could be determined by measuring the absorbance at 480 or 490 nm against the reagent blank. All other interferring ions, such as Hg(II), Cu(II), Ni(II), Pb(II), Zn(II), and Fe(III), extractable together with cobalt(II) could be stripped out of the organic phase by shaking it with 1–12m hydrochloric acid, while cobalt remained in the organic phase as it was. After this treatment, the organic phase was shaken with an aqueous buffer solution of pH 9–11; thereby, the excess of the reagent was released to a great extent from the organic phase into the aqueous solution. The cobalt-STTA chelate was then the only one existing in the organic phase; therefore, the sensitivity and the selectivity of the method increased so much that a few ppb of cobalt(II) could be determined precisely by measuring the absorbance of the final organic phase at 360 nm against the reagent blank. In this work, the apparent mole ratio of STTA to cobalt in the complex formation was estimated to be 4:1, and the molar absorption coefficients of the chelate in cyclohexane were found to be 4970000 (at 360 nm), 13200 (at 450 nm), 6500 (at 480 nm), and 5500 (at 490 nm) respectively. Anions, such as oxalate and citrate, as well as EDTA interfered with this extraction. By the recommended procedure, cobalt of a few ppb in an analytical-grade reagent of nickel nitrate hexahydrate could be determined.
Studies on Stable Free Radicals. XIII. Synthesis and ESR Spectral Properties of Hindered Piperazine N-Oxyls
Authors: Yoshioka Takao , Mori Eiko , Murayama Keisuke 
Published: July 2006

Abstract
New hindered 3,5-dioxopiperazines (VII, IX), hindered piperazines (VIII, X), and the corresponding N-oxyls (XI, XIII, XII, and XIV) were synthesized. The substituent and solvent effects of the nitrogen coupling constants (aN) in the N-oxyls were measured and compared with each other; the introduction of carbonyl groups at the C-3 and C-5 ring positions decreased these values, which increased in a protic polar solvent.
Steric Effect in the Nucleophilic Attack of Bromide Anion on Diaryl- and Aryl-2-thienyliodonium Ions
Authors: Yamada Yorinobu , Okawara Makoto 
Published: July 2006

Abstract
Duryl-, mesityl-, and o-tolyl-phenyl- and 2-thienyliodonium bromides have been synthesized. When these substances were allowed to decompose in molten (235°C) and solution (100°C) states, the nucleophile (bromide anion) preferentially attacked the substituted phenyl ring. Steric and electronic effects of phenomena have been discussed.
Chemistry of Nitrosoimines. II. Photolysis of 2-Nitrosoimino-2,3-dihydrothiazoles
Authors: Akiba Kin-ya , Fukawa Isaburo , Nomura Noboru , Inamoto Naoki 
Published: July 2006

Abstract
Irradiation of 3-substituted 2-nitrosoimino-2,3-dihydrobenzothiazoles (I) with a medium pressure mercury lamp gave bis[o-(N-substituted cyanamino)phenyl] disulfides (III) in high yields. Irradiation of 4,5-diphenyl-2-nitrosoimino-2,3-dihydrothiazole (VI) gave bis[(2-phenyl-2-N-phenylcyanamino)vinyl] disulfide (VIII).
The photolysis was shown to be due to the π-π* excitation from the results of specific irradiation to π-π* and π-π* bands. The relative rates of photolysis of 2-nitrosoimino-3-phenyl-2,3-dihydrobenzothiazole (Ia) were measured in several solvents. The mechanism has been discussed in connection with that in alkyl nitrites and nitrosamines.
Automatic Problem Solving Applied to Synthetic Chemistry
Authors: Bersohn Malcolm 
Published: July 2006

Abstract
The first computer program that plans multi-step organic syntheses has been written. In the course of its operation the program generates partially complete synthetic pathways and ranks them as to efficiency. At each stage the program develops that partially complete route which it judges to be the most efficient, and extends it by one step. Partially complete routes which lose too much material are discarded. After each tolerably efficient pathway from available starting materials to the goal molecule is completed, the entire pathway is printed, together with the yield of each step and the overall yield.
Studies on Stable Free Radicals. IX. Peroxy Acid Oxidation of Hindered Secondary Amines to Nitroxide Radicals
Authors: Toda Toshimasa , Mori Eiko , Murayama Keisuke 
Published: July 2006

Abstract
The hindered secondary amines, 2,2,6,6-tetramethyl-4-oxopiperidine (II) and 1,9-diaza-2,2,8,8,10,10-hexamethyl-4-oxo-spiro[5.5]undecane (VI), were oxidized with m-chloroperbenzoic acid, and the corresponding hydroxylamine (III) and N-oxyl-hydroxylamine (VIII), respectively, were isolated. The further oxidation of III and VIII with the peracid afforded the corresponding nitroxide radical IV and IX, in good yields respectively. The stoichiometry of the oxidation reaction of the hydroxylamine III to the nitroxide radical IV was elucidated on the basis of the ESR signal intensities of oxidation products at various molar ratios with the peracid and III. An ESR study of the 1-15N-labelled N-oxyl-hydroxylamine (XII) indicated that there was an intramolecular hydrogen transfer between &gt;N–OH and &gt;N–O · groups in the N-oxyl-hydroxylamines VIII and XII.
Dimerization and Electronic Absorption Spectra of Tetracyanoethylene Anion in Solution and in Solid
Authors: Itoh Michiya 
Published: July 2006

Abstract
The 2-methyltetrahydrofuran solutions of several alkali tetracyanoethylenides (M+, TCNE−, where M=Na, K, Rb, and Cs) show strong visible absorption spectra at low temperature which might be considered to be charge-transfer bands between two TCNE anions. Temperature dependence of the electronic absorption and ESR spectra of TCNE− in solution yields the monomer-dimer equilibrium of the TCNE anion. The heat of dimer formation of the anion was found to decrease in the order Na+&gt;K+&gt;Rb+&gt;Cs+ with the size of the counter ions. The heat of dimer formation in Na+(TCNE)− also depends considerably on the solvent system. The absorption spectra of the solid TCNE anions were found to resemble the spectrum of the TCNE anion dimer (TCNE−)2 in solution to a great extent. A comparison of the electronic absorption and ESR spectra of M+(TCNE)− in solution and in solid demonstrates that the solid TCNE− is almost diamagnetic, and the anion dimer can be the unit of structure in the solid salts.
Exciton-Exciton Interaction and Exciton Migration in Anthracene, Pyrene, and Perylene Crystals
Authors: Inoue Akinori , Yoshihara Keitaro , Nagakura Saburo 
Published: July 2006

Abstract
The bimolecular annihilation of singlet excitons in pyrene, perylene, and anthracene crystals was studied by the aid of a nitrogen gas laser. The rate constant, γ, for bimolecular annihilation was estimated at 293°K to be 9×10−15 and 8×10−14 cm3 sec−1 for pyrene and perylene, respectively. The temperature dependence of γ was measured with the result that it increases with the increasing temperature for the pyrene and perylene crystals, while it is almost independent of temperature for anthracene between 77°K and 293°K. The difference in the temperature dependence of γ was attributed to the difference in the mechanism of the exciton migration of the crystals. The method developed by the present authors for studying the exciton migration based on the exciton bimolecular annihilation was compared with that obtained previously by the use of mixed crystals.
Kinetics of the Acid Hydrolysis of Carboxylatopentammineruthenium(III) Complexes
Authors: Ohyoshi Akira , Jyo Akinori , Shin Noriaki 
Published: July 2006

Abstract
The kinetics of the hydrolysis of pentammineruthenium(III) complexes containing carboxylates and α-substituted acetates (glycolate and glycinate) have been studied. The experiments were carried out in a solution of [H+]=0.025–0.1m, at 40–70°C. For each complex, the rate law was found to be: rate=[complex](kH2O+kH[H+]). The kH2O and kH values for the formato, acetato, propionato, isobutyrato, glycolato, and glycinato complexes are, respectively (at μ=0.10, 59–61°C): kH2O, 5.37×10−5, 11.8×10−5, 14×10−5, 13.7×10−5, 5.7×10−5, and 6.75×10−5sec−1; kH, 3.3×10−3, 2.3×10−3, 2.5×10−3, 1.7×10−3, 0.75×10−3, and 3.1×10−3M−1sec−1. The mechanisms of acid hydrolysis are discussed for the two reaction paths.
Syntheses of Formato-, Acetato-, Benzoato-, and Chlorosubstituted Acetatoruthenium Complexes, and Their Properties
Authors: Mukaida Masao , Nomura Terunosuke , Ishimori Tatsujiro 
Published: July 2006

Abstract
Complexes with the general formula of [Ru2(RCOO)4X], where R=H, X=Cl, or Br; R=Me, X=Cl, Br, I, SCN, NO3, or MeCOO; R=ph, X=Cl, or Br, were prepared. The magnetic properties, conductivities, polarographic behavior, and infrared spectra of these complexes were investigated. All the complexes show magnetic moments of 2.84–2.96 B.M., and their susceptibilities, at from about 300 to 100°K, can be fitted to the Curie-Weiss law with negative values of the Weiss constant (θ=−30–−60°K). These complexes seem to be isostructural. Monochloroacetato-, and trichloroacetatoruthenium complexes ([Ru2(CH2ClCOO)4Cl]·2H2O and [Ru(OH)(CCl3COO)2(H2O)]) were also prepared.
Studies of Ethylenediamine-N,N′-diacetatocobalt(III) Complexes. The Preparation and Identification of Ethylenediamine-N,N′-diacetatocobalt(III) Complexes with Ammonia, Pyridine, or Alkylamines as the Additional Ligand
Authors: Kuroda Kashiro 
Published: July 2006

Abstract
A group of cobalt(III) complexes containing the tetradentate ethylenediamine-N,N′-diacetate anion (EDDA) and ammonia, pyridine, or alkylamines have been derived from ethylenediamine-N,N′-diacetato(diaquo)cobalt-(III) perchlorate. Three different series among the complexes—(1) the aquo(amine) series, [Co(EDDA)(H2O)-(am)]ClO4, (2) the α-cis-bis(amine) series, α-cis-[Co(EDDA)(am)2]ClO4, and (3) β-cis-[Co(EDDA)(NH3)2]ClO4 as well as β-cis-[Co(EDDA)(en)]ClO4, have been obtained, depending on the conditions of the reaction between the starting diaquo complex and the amines. Some properties of the complexes have been examined, and the geometrical configuration of each complex has been identified on the basis of the electronic absorption spectra and the proton NMR spectra. The coordination tendency of EDDA and the amines have also been discussed.
The Crystal and Molecular Structure of Butein Monohydrate, Isolated from Dahlia variabilis
Authors: Saito Norio , Ueno Katsuhiko , Sasada Yoshio 
Published: July 2006

Abstract
The crystals of butein monohydrate isolated from Dahlia variabilis are monoclinic. The unit cell, with dimensions of a=10.89, b=28.88, c=4.29 Å, and β=96.7°, contains four molecules, and the space group is P21/n. An approximate structure was obtained by applying the symbolic addition procedure. The structural parameters were refined by the block-diagonal least-squares method, and the final R factor for 1063 observed reflexions was 0.171. In the molecule, the C(7)–C(8) double bond and the C(9)–O(3) carbonyl group take the s-cis conformation with respect to the C(8)–C(9) single bond. The A phenyl group and the exocyclic atoms (C(7)∼O(3)) are nearly coplanar, and this plane makes a dihedral angle of 15.6° with that of the B phenyl group. The molecules build up a three-dimensional net through the hydrogen bonds. There is also an intramolecular hydrogen bond between O(3) and O(4).
The Normal Magneto-Optical Rotatory Dispersion and the Magnetic Moment of Benzene
Authors: Takenoshita Yoshiya 
Published: July 2006

Abstract
The magneto-optical rotatory dispersion in the absorptionless region has been investigated with liquid benzene, and the related magnetic moment has been discussed theoretically. It has been concluded that the main contribution to the magneto-optical rotatory dispersion consists of an A term through the 1A1g→1E1u transition and that the contribution from σ -electrons is never negligible. The magnetic moment in the excited state, 1E1u, of benzene has been obtained as −1.72 β (Bohr magneton), which is about 2 or 4 times greater than the value of −1.0 β calculated with the FEN-model or the value of −0.396 β calculated by the LCAO-MO method.
The Vibrational Spectra of Water of Crystallization in Barium Chlorate Monohydrate, Calcium Sulfate Dihydrate and Copper Chloride Dihydrate Crystals
Authors: Fukushima Kunio , Yanagida Tsutomu 
Published: July 2006

Abstract
Infrared spectra of water of crystallization and heavy water of crystallization were mesasured for Ba(ClO3)2·H2O, CaSO4·2H2O, CuCl2·2H2O, Ba(ClO3)2·D2O, CaSO4·2D2O, and CuCl2·2D2O, in which the divalent metal ion lies on the bisector line of H–O–H angle or D–O–D angle. From a comparison of the spectra, assignment of the infrared absorption bands was made for the rotational and the translational vibrations of the water of crystallization.
Palladium-catalyzed Exchange of Allylic Groups of Ethers and Esters with Active Hydrogen Compounds. II.
Authors: Takahashi Kuniyuki , Miyake Akihisa , Hata Go 
Published: July 2006

Abstract
The allylic compounds (I), R1–O–R (R=allylic groups, R1=Ph, Me, PhCH2, MeCO), react with active-hydrogen compounds such as phenols, alcohols, carboxylic acids, primary and secondary amines and active methylene compounds, to give allylic derivatives of the active-hydrogen compounds by an intermolecular exchange of the allylic groups of I with the atom to which the active hydrogens are bonded in the presence of palladium catalysts. Allyl and substituted-allyl ethers are more reactive than the corresponding carboxylates. In the reactions of methyl and benzyl ethers, it is necessary to add phenol to obtain the exchange products in fairly good yields. Bis(triphenylphosphine) palladium chloride plus sodium phenoxide, palladium acetate plus triphenylphosphine, and zerovalent palladium complexes such as tetrakis (triphenylphosphine) palladium and (maleic anhydride)bis(triphenylphosphine)palladium are effective catalysts.
Origin of the Fine Structure of the Electronic Spectra of Pyrazine in Benzene Crystals
Authors: Suzuka Isamu , Ito Mitsuo 
Published: July 2006

Abstract
The absorption, fluorescence, and phosphorescence spectra of pyrazine doped in benzene crystal have been observed at 4.2°K. It was found that the 0-0 band and the main vibronic bands are accompanied by the fine structures consisting of several very sharp bands and few broad bands. A detailed examination of the fine structures has suggested that the sharp bands arise from the differently oriented guest molecules in the host crystal, and the broad bands come from coupling of the host crystal phonon with the guest molecule.
The Formation of Metallic Silver in Silver-Form Zeolites
Authors: Tsutsumi Kazuo , Takahashi Hiroshi 
Published: July 2006

Abstract
The formation of silver crystallites in silver-form zeolites was investigated, mainly by means of X-ray diffraction analysis. Silver ions were reduced to the zero-valent state; they aggregated to metals in three cases in this study—first, when silver-form zeolites were heated in a helium flow at above 600°C; secondly, when they were reduced by hydrogen, and lastly, when they were treated with the alkyl benzenes or alcohols above 300°C. The silver crystallites had sizes of 150–400, 150–200, and 200–300Å respectively when Ag(31.6%)–Na–Y4.6 was rereduced in the three cases mentioned above. If the silver ions are reduced, the zeolite becomes decationated-form, in which metallic silver is dispersed. The silver metals formed in the zeolite have peculiar interactions with oxygen.
Calculation of the Reduced Partition Function Ratios of α-, β-Quartzs and Calcite
Authors: Shiro Yuji , Sakai Hitoshi 
Published: July 2006

Abstract
The reduced partition function ratios (r.p.f.r.) of α,β-quartz and calcite were calculated for oxygen isotopic substitution, using the force fields. Optical vibrations are represented by factor group mode (k=0) and acoustic contributions were approximated by the Debye mode of vibration. The theoretical calculation predicts that the r.p.f.r. of quartz could have a discrete gap of about 0.8% at the α-β-transition temperature (573°C), the r.p.f.r. of α-quartz being larger in magnitude and in temperature-dependency. This implies that the isotopic fractionation factors between quartz and other materials such as water, could be significantly affected by the transition. A comparison of the calculated r.p.f.r. of quartz and calcite with the experimental fractionation factors between these minerals and water yields a fairly consistent value of the r.p.f.r. of water, supporting the force field models used for calculations. The comparison also revealed that the r.p.f.r. of water in the temperature interval 300–800°C and under a hydrostatic pressure of 2 Kb should deviate from those of ideal water vapor at the same temperatures by as much as 1% due to the non-ideality of the compressed water fluid.