bluuebunny/crossref_metadata_2025_split huggingface dataset:
Molecular Structure of Dimethyltin Dichloride as Studied by Gas-electron Diffraction
Authors: Fujii Hideji , Kimura Masao 
Published: July 2006

Abstract
The molecular structure of dimethyltin dichloride was determined by the sector-microphotometer method of electron diffraction to be as follows: rg(Sn–Cl)=2.327±0.003 Å, rg(Sn–C)=2.108±0.007 Å, and rg(C–H)=1.113±0.020 Å, and all the valency angles were near 109.5°. In comparison with the Sn–Cl distances in the series of Sn(CH3)4−nCln, as determined previously by the same method, a regular bond contraction in going from Sn(CH3)3Cl to SnCl4, as pointed out previously by Skinner and Sutton, was ascertained.
Effects of para-Substituents on the Rates of Inversion of Biphenyl Derivatives. II. 2-Isopropyl-2′-methoxybiphenyls
Authors: Oki Michinori , Yamamoto Gaku 
Published: July 2006

Abstract
Nine 4,4′-substituted 2-isopropyl-2′-methoxybiphenyls were synthesized and temperature dependence of the NMR spectra of these compounds was examined. The effects of the substituents on the energy barrier to inversion of the biphenyl skeleton can be interpreted in terms of both resonance stabilization and out-of-plane bending of the axis bond at the transition state. In the latter, an electron-donating substituent makes the bond bendig easier and lowers the barrier, whereas an electron-withdrawing group raises the barrier.
Correlation between the Transition Temperature and the Rotational Potential Barrier in Plastic Crystals
Authors: Chihara Hideaki , Koga Yoshikata 
Published: July 2006

Abstract
A linear retationship was found between the transition temperature of plastic crystals and potential energy barrier hindering molecular rotation determined below or above the transition point, with the slope of the line 7.5 R and 4.1 R, respectively, where R is the gas constant. Consideration of the distribution of molecules between the librational and the rotational states showed that the transition starts to occur cooperatively when the fraction of the rotating molecules reaches a value of 1/60 and concludes with a value of 1/3. The model gives the entropies of transition which reasonably agree with the observed values.
Gas Chromatography of Aluminum, Gallium, and Indium β-Diketone Chelates
Authors: Utsunomiya Kei 
Published: July 2006

Abstract
The gas-chromatographic behavior of aluminum(III), gallium(III), and indium(III) chelates with various β-diketones was investigated. The β-diketones studied were acetylacetone and 8 synthesized, alkyl-substituted acetylacetones, benzoylacetone, dibenzoylmethane, trifluoroacetylacetone and its 5 synthesized alkyl derivatives, hexafluoroacetylacetone, benzoyltrifluoroacetone, furoyltrifluoroacetone, and thenoyltrifluoroacetone. The trifluoromethyl group increases the volatility of the chelates, while the aromatic group tends to decrease the volatility. In the alkyl-substituted acetylacetone series, the retention time of the chelates increases with an increase in the molecular weight, but it does not depend upon the volatility. On the other hand, the retention of the chelates containing the trifluoromethyl group is almost inversely correlated with the volatility.
The Determination of the Amount of Oxygen in Molten Copper-Nickel and Copper-Silver Alloys by the EMF Method
Authors: Tsukahara Iwao 
Published: July 2006

Abstract
Using the following solid oxide-electrolyte galvanic cells, Pt/air//ZrO2 (+CaO) O//(in Cu–Ni alloy)/Mo and Pt/air//ZrO2 (+CaO) O//(in Cu–Ag alloy)/Mo, the electromotive forces of the cells have been measured as a function of the oxygen concentration in copper-nickel or -silver alloys at oxygen concentrations ranging from several ppm to 1000 ppm, at 1210°C for copper-nickel alloys and at 1100°C or 1200°C for copper-silver alloys respectively. The activity coefficient of oxygen has been determined from the electromotive force for the alloy systems investigated. In the case of copper-nickel, the activity coefficient of oxygen decreases with an increase in the nickel concentration and also with a decrease in the oxygen concentration. The solubility of oxygen in the copper-nickel alloy has also been measured at 1210°C by the use of the following galvanic cell, Pt/air//ZrO2(+CaO)//O(in Cu–Ni alloy), NiO/Mo.
Electrolyses of 2,2-Dichloro-3-phenylcyclopropanecarboxylic Acids in Hydroxylic Solvents with a Platinum Anode
Authors: Takeda Akira , Wada Satosi , Murakami Yasuo 
Published: July 2006

Abstract
Electrolysis of 2,2-dichloro-3-phenylcyclopropanecarboxylic acid (1a) in hydroxylic solvents such as methanol and acetic acid, or in aqueous methanol with acetic acid in excess, was carried out with a platinum anode. Solvolysis rather than coupling was found to occur yielding 3,3-dichloro-1-phenylallyl methyl ether (4a) or 3,3-dichloro-1-phenylallyl acetate (5a), or both, depending on the solvent. Electrolysis of 2,2-dichloro-3-methyl-3-phenylcyclopropanecarboxylic acid (1b) in aqueous methanol gave ether 4b. Structural characterization of the products was also discussed.
Chemical Constituents of Alnus sieboldiana (BETULACEAE) II. The Isolation and Structure of Flavonoids and Stilbenes
Authors: Asakawa Yoshinori 
Published: July 2006

Abstract
Four new flavonoids with an unsubstituted B-ring, alnusin, alnetin, alnustin, and alnustinol, isolated from Alnus sieboldiana were established to be 3,5,7-trihydroxy-6-methoxyflavone (1), 5-hydroxy-6,7,8-trimethoxyflavone (2), 5-hydroxy-3,6,7-trimethoxyflavone (3), and 3,5,7-trihydroxy-6-methoxyflavanone (15) respectively. Some previously-known flavonoids, chrysin (4), izalpinin (5), tectochrysin (6), pinocembrin (16), pinobanksin (17), strobopinin (19) and naringenin (20), and some stilbenes, pinosylvin (24), pinosylvin monomethyl ether (25), and pinosylvin dimethyl ether (26), were identified along with the above new flavonoids.
The Crystal and Molecular Structure of Miyaconitine Hydrobromide Dihydrate
Authors: Shimanouchi Hirotaka , Sasada Yoshio , Takeda Tatsumichi 
Published: July 2006

Abstract
The structure of an Aconitum alkaloid, miyaconitine, C23H29O6N, has been determined by the X-ray analysis of crystals of the hydrobromide dihydrate, which are monoclinic with four formula units in a unit cell of the dimensions; a=10.41, b=13.85, c=9.63 Å and β=113.8°; space group, P21 The structure was solved by the heavy-atom method and was refined by the least-squares method. The final R index was 0.151. The absolute configuration was determined using the anomalous dispersion effect of the bromine atom. It was thus established that miyaconitine is a novel type of Aconitum alkaloid.
The Reactions of Grignard Reagents with Transition Metal Halides: Coupling, Disproportionation, and Exchange with Olefins
Authors: Tamura Masuhiko , Kochi Jay K 
Published: July 2006

Abstract
The reactions of transition metal halides (Mn, Fe, Co, Ni, Pd, Cu, and Ag) with the low-molecular-weight alkyl Grignard reagents in tetrahydrofuran and diethyl ether, especially in the presence of styrene were reinvestigated. An alkyl transition metal species formed in situ by metathesis decomposed to a dialkyl (oxidative dimerization) or to an alkene and an alkane (oxidative disproportionation). Silver(I) and copper(II) were particularly effective in oxidative dimerization of primary alkyl groups. Alkyl groups which contain no β-hydrogen were also coupled by iron, cobalt, nickel, palladium, and copper(I) halides with varying degrees of efficiency. Oxidative disproportionation was generally the more common route to decomposition for alkyl groups which have β-hydrogens. It seemed to proceed directly via a bimolecular interaction of alkylmetals or indirectly by elimination of a hydrido-metal species. If the latter added to an alkene reversibly, exchange was observed between Grignard reagent and alkene. Styrene was reduced to ethylbenzene during the reaction both in tetrahydrofuran and in diethyl ether in varying yield with transition metal halide and Grignard reagent. In addition to alkyl exchange, dehydrogenation of the ethereal solvent by active (reduced) metal species complicated the stoichiometry of decomposition as measured by the value of the empirical parameter, Q,(R). The selection of transition metal in addition to the temperature, solvent and triphenylphosphine was effective variables in promoting the efficiency of the exchange process.
Imidazole Catalyses in Aqueous Systems. VIII. Spontaneous Hydrolysis and Michaelis-Menten-type Catalytic Hydrolysis of Phenyl Esters in the Presence of Cholic Acid and Its Histamine Derivative
Authors: Shinkai Seiji , Kunitake Toyoki 
Published: July 2006

Abstract
Spontaneous hydrolyses of cationic and anionic phenyl esters in the presence of cholic acid (VI) and their catalytic hydrolyses with a histamine amide of cholic acid (VII) were investigated using a pH-stat at 30°C in 1.0m aqueous KCl. The rates of spontaneous hydrolysis decreased by 30–70% upon binding of substrates with cholic acid. The variation of the apparent binding constant (7-3650m−1) was considered to reflect the magnitude of hydrophobic forces between cholic acid and substrates, although the values may have to be corrected for the possible involvement of self-association of cholic acid molecules. Imidazole derivative VII catalyzed the hydrolysis of phenyl esters according to Michaelis-Menten kinetics. The long methylene chain in the substrate molecule contributed appreciably to the binding of substrate with cholic acid and its derivative. The magnitude of substrate binding with VII appears to be comparable to the true binding constant with cholic acid. The intracomplex rate constants did not differ much from those expected with other enzyme-like catalysts. Thus, the steroid ring seems to provide a non-specific hydrophobic binding site for the substrates used.
The Conversion of Some Alkylxanthates to the Corresponding Trithiocarbonates. The Nucleophilic Reaction of −SCSSR
Authors: Yoshida Hiroshi , Ogata Tsuyoshi , Inokawa Saburo 
Published: July 2006

Abstract
The reaction of O-methyl-, ethyl-, and benzylxanthates with a catalytic amount of triethylamine in the presence of excess carbon disulfide gave the corresponding trithiocarbonate in good yields. The products were formed by the nucleophilic reaction of −SCSSR with xanthates. The kinetic study showed the following order of nucleophilicity toward xanthates in DMF:
−SCOSMe&gt;−SCSSMe&gt;Me3N
Studies of the Synthesis of Furan Compounds. XXV. 2-[2-(5-Nitro-2-furyl)-1-(4-cyanophenyl)vinyl]-1,3,4-oxadiazoles and -1,3,4-thiadiazoles
Authors: Hirao Ichiro , Kato Yasuhiko 
Published: July 2006

Abstract
5-Amino-2-[2-(5-nitro-2-furyl)-1-(4-cyanophenyl)vinyl]-1,3,4-oxadiazoles and -1,3,4-thiadiazoles have been synthesized from 3-(5-nitro-2-furyl)-2-(4-cyanophenyl)acrylic acid according to a procedure previously described. All of these compounds exhibit strong antibacterial activity against Staphylococcus aureus, but they exhibit a weak activity, or almost no activity, against the other microorganisms tested.
Conformations of the Esters. II. The Conformation of Alkyl Acetates
Authors: Oki Michinori , Nakanishi Hiroshi 
Published: July 2006

Abstract
Alkyl acetates which carry secondary and tertiary alkyl groups have been found to have bifurcated bands in the carbonyl region of the infrared spectra. The origin of the bifurcated bands has been studied carefully, and it has been concluded that the Fermi resonance is the most probable origin of the phenomenon.
Photolytic and Thermal Decompositions of 5-Substituted 1,2,3,4-Thiatriazoles in the Presence of Olefins. Reactions of Sulfur Atoms
Authors: Okazaki Renji , Okawa Kazumi , Wajiki Seiji , Inamoto Naoki 
Published: July 2006

Abstract
Photochemical decompositions of 5-phenyl- and 5-amino-1,2,3,4-thiatriazoles in the presence of cyclohexene or tetramethylethylene led to the formation of the corresponding episulfide, the production of which has been explained in terms of sulfur atom reactions with the olefins. Kinetic measurements revealed the limitation of the reactions as a synthetic method of an episulfide from an olefin. Mechanism of the episulfide formation was briefly discussed. Thermal decompositions of these thiatriazoles in the presence of olefins gave rise to no episulfides.
On the Factors Determining the Molecular Arrangement in Crystalline Ethylene
Authors: Hashimoto Masao , Hashimoto Michiko , Isobe Taro 
Published: July 2006

Abstract
The orientation-dependent potential energy of the ethylene crystal was calculated using a somewhat modified expression for the dispersion energy in the case of non-axially symmetric molecules. It was concluded that the main force which determines the angle between the bc plane and the C=C bond axis in the ethylene crystal is the dispersion; on the other hand, it is the quadrupole-quadrupole interaction which determines the angle between the ab plane and the C=C bond axis. The expected molecular arrangement in the crystalline ethylene belongs to the space group P21/n, this is consistent with the conclusion obtained from the spectroscopic data.
Solvent Effect on the Vibrational Structures of the Fluorescence and Absorption Spectra of Pyrene
Authors: Nakajima Akira 
Published: July 2006

Abstract
The anomalously large Ham effect observed in pyrene has been studied in various solvents at room temperature by measuring the fluorescence and absorption spectra. As in the case of benzene, the Ham bands of pyrene were assigned to the 0–0 and ag-vibration bands. This was confirmed by fluorescence polarization measurement. The correlation of the intensities of the fluorescence and absorption bands to solvent polarities is discussed.
The Catalytic Dehydrohalogenation of Haloethanes on Solid Acids and Bases
Authors: Mochida Isao , Anju Yasuhide , Yamamoto Hiroko , Kato Akio , Seiyama Tetsuro 
Published: July 2006

Abstract
The elimination reactions of haloethanes and halopropanes on solid acids and bases, including a series of metal sulfates supported by silica gel, were studied at 300°C by means of the pulse technique in order to clarify the mechanism of the catalytic dehydrohalogenation. The trans-1,2-dichloroethylene/cis-1,2-dichloroethylene (trans-1,2/cis-1,2) selectivities from 1,1,2-trichloroethanes as well as the activities of the metal sulfates supported by silica gel were well correlated with the electronegativities of the metal ions. Generally speaking, the rates of the dehydrochlorination from chloroalkanes were nearly equal to those of the dehydrobromination from bromoalkanes on the solid acids, but the latter were larger than the former on solid bases. The reactivities of the alkylhalides on solid acids and bases were examined from the electronic view-point, and we tried to correlate them with some reactivity indexes. A kinetic isotope effect with regard to hydrogen was observed on solid bases, but not on solid acids, in the dehydrobromination of 1,2-dibromoethane. From these facts, it was concluded that the dehydrohalogenation proceeds through a carbonium-ion mechanism on solid acids and via an E2 step-by-step mechanism on solid bases.
Theoretical and Experimental Considerations of the Direct Photo-Isomerization and Chemistry of 1,3-Pentadiene
Authors: Inuzuka Kozo , Becker Ralph S 
Published: July 2006

Abstract
Potential energy curves as a function of the angle of twist around single and double bonds have been calculated for piperylene (1,3-pentadiene). Also, direct-excitation cis→trans photoisomerization and trans→methycyclobutene photochemistry have been investigated as a function of the temperature. The theoretical analysis strongly indicates that the cyclobutene is formed photochemically from the trans-s-cis isomer which is created thermally from the trans-homer in the ground state (not by photoisomerization). The temperature-dependency data support this conclusion. The theoretical data also indicate that there is a small barrier to photoisomerization around the double bond in the first excited singlet (and triplet) state. The temperature-dependency data also support this conclusion. The potential energy curves are in harmony with the known emission (none exists), photoisomerization, and internal-conversion data for the cis- and trans-piperylenes. The emission properties of model cyclic diene steroids are compared with those expected from linear dienes, and the emission results of the former are interpreted within the theoretical framework developed.
Metal Complexes with Amino Acid Amides. III. Geometrical Structures and Electronic Spectra of Bis(α-amino-acid-amidato)palladium(II), nickel(II) and Copper(II)
Authors: Komorita Takashi , Hidaka Jinsai , Shimura Yoichi 
Published: July 2006

Abstract
Square planar complexes of [ML2] type were synthesized, where M=Pd2+ and Ni2+ for L=l-valine-, l-phenylalanine- and l-proline-amidate anions, and M=Pd2+, Ni2+ and Cu2+ for L=l-leucinemethylamidate anion and for L2=trimethylenediamine-N,N′-diisobutyric acid amidate dianion; the last ligand is a tetradentate one and gives exclusively cis type complexes. Cis and trans isomers were isolated and identified for each of the l-valinamidato and the l-prolinamidato palladium complexes. All the other complexes were inferred to be trans isomers from examination of the electronic absorption and circular dichroism spectra. Common solvent effects of the ligand field bands were clearly observed between the trans palladium and trans nickel complexes. A similar empirical relationship was also found between the ligand field bands of the trans palladium complexes and those of the corresponding cis isomers. The spectral behavior of the bis(l-amino-acid-amidato)-copper(II) complexes was not so easily related to that of the corresponding nickel or palladium complexes. The ligand field bands of the palladium, nickel, and copper complexes were tentatively assigned.
Infrared Absorption Spectra and Normal Coordinate Analysis of Metal-Dl-α-Serine Chelates
Authors: Inomata Yoshie , Inomata Tadaaki , Moriwaki Takao 
Published: July 2006

Abstract
The infrared absorption spectra of Dl-α-serine and four metal-Dl-α-serine chelates have been investigated from 4000 to 200 cm−1. A normal coordinate analysis has been accomplished for the metal chelates as a 27-body problem and an approximate description of the vibrational mode has been assigned to the observed frequencies. The frequency separation between carboxylate antisymmetric and symmetric stretching vibrations and values of the bond-stretching force constants for the metal-nitrogen bonds have been found to decrease in the order Pt(II)&gt;Pd(II)&gt;Cu(II)&gt;Ni(II). These facts show that the hydroxy group in the β-position of Dl-α-serine has no influence on the order of metal-ligand bond strength, which order has been already found in aliphatic α-amino acids chelates having no hydroxy group in the β-position. Two species of copper chelates have been prepared. Though the infrared spectrum of one of them is similar to that of the nickel(II) chelate, that of the other species is different. This fact may be explained by assuming that the copper ion has been coordinated with the hydroxy group in the latter.
Inclusion Compounds of Some Charge-Transfer Complexes
Authors: Ohmasa Masatake , Kinoshita Minoru , Akamatu Hideo 
Published: July 2006

Abstract
The charge-transfer complex of benzidine and tetracyano-p-quinodimethane has been shown to form an inclusion compound with certain molecules such as dichloromethane, dibromomethane and acetone. The molecular volumes of these guest substances are all smaller than 75 cm3/mol, while the substances which are not included have a molecular volume larger than 80 cm3/mol. Besides the size, the molecular shape is also considered to be a primary factor for the formation of the inclusion compound. The heat of formation of the inclusion compound with dichloromethane as a guest was determined to be 11.1±1 kcal per mole of the guest substance by the thermochemical measurements. Similar inclusion compounds were also obtained, when 3,3′-diaminobenzidine, 3,3′-dichlorobenzidine and o-tolidine were used in place of benzidine.
Electronic Properties of Benzidine·TCNQ System
Authors: Ohmasa Masatake , Kinoshita Minoru , Akamatu Hideo 
Published: July 2006

Abstract
The benzidine·tetracyano-p-quinodimethane (TCNQ) system forms two types of charge-transfer complexes; one (I) containes some sort of solvent molecules, while the other (II) does not. The electronic properties of I have been found to be unusual in many respects compared to II which shows the properties expected from those of ordinary charge-transfer complexes. I and II did not exhibit ESR absorption, if they were well-grown crystals. However, when they were pulverized to fine powder, I showed a strong absorption while II did not. The visible range absorption spectra of I and II consisted of three main bands, but all the bands of I were found to be shifted to longer wavelengths compared to those of II. In addition to these bands, two shoulders were found in the spectrum of I. The shoulders were considered to be due to the ion radicals produced from benzidine and TCNQ. The electrical resistivities are again quite different from one another. The resistivity of I was found to be 103–105 ohm cm at room temperature, the value being dependent on the kind of the solvent molecules included, while that of II was 2×109 ohm cm. The activation energy for conduction was smaller for I (0.1–0.2 eV) than for II (0.34 eV).
Distribution of Nickel across the Thickness of Al Anodic Oxide Films Sealed in Nickel Sulphate Solutions
Authors: Campanella Luigi 
Published: July 2006

Abstract
The distribution of nickel across the thickness of Al anodic oxide films, produced in 15.5% w/v H2SO4 as electrolyte and sealed in nickel sulphate solutions, is determined and an approximate confirmation of the conical shape of pores is obtained.
The Effect of Consecutive Complex Formation on the Separation of Rare Earths by Electromigration
Authors: Ohyoshi Emiko 
Published: July 2006

Abstract
The effect of a complexing agent with which rare earths consecutively form complexes on the separation of an adjacent pair of rare earths by electromigration was investigated. By assuming the complexes ML and ML2 to be formed, the relation of the separation factor, the difference in the zone mobility of the two rare earths, to the ligand-ion concentration was derived and examined for the separation of the La-Ce and Ce-Pr pairs by using nitrilotriacetic acid (NTA), which is known to form the ML and ML2 complexes with rare earths. It is found that the separation factor is affected not only by the difference in the first (k1) or the second (k2) consecutive formation constant of the two elements to be separated, but also by the value of the k1/k2 ratio.
Studies of the Synthesis of Furan Compounds. XXII. Synthesis and Antibacterial Activity of 5-[2-(5-Nitro-2-furyl)-1-(2-furyl)vinyl]-2-amino-1,3,4-thiadiazole and Its Related Compounds
Authors: Kato Yasuhiko 
Published: July 2006

Abstract
In continuing our study of the relationship between structures and antibacterial activity, 5-[2-(5-nitro-2-furyl)-1-(2-furyl)vinyl]-2-amino-1,3,4-thiadiazole and related derivatives have been synthesized. Their structures were confirmed by their chemical reactions and by their UV, IR, and NMR spectra. 1,3,4-Thiadiazole and its related derivatives show significant antibacterial activity.