bluuebunny/crossref_metadata_2025 huggingface dataset:
Reinvestigation of the Nontotally Symmetric g-Type Normal Vibrations of [1H4]- and [2H4]Pyrazines
Authors: Hieida Toshikazu , Maehara Masayoshi , Nibu Yoshinori , Shimada Hiroko , Shimada Ryoichi
Published: July 2006

The assignment of the nontotally symmetric g-type normal vibrations of [1H4]- and [2H4]pyrazines was reinvestigated through the analyses of the single vibronic level fluorescence spectrum. The assignment given in this work was consistent with the assignment made based on the polarization behavior of the phosphorescence spectrum.
Sulfur Pressure Control in an H2–Sulfur Vapor System
Authors: Wada Hiroaki
Published: July 2006

A direct sulfur pressure control method by a N2–sulfur vapor system was modified by using an H2–sulfur vapor system. A ratio of H2S/H2 in the atmosphere was found to be controlled very well in the range from 10−2 to 10−4 only by the temperature regulation.
Synthesis of the 1H,5H-Naphtho[1,8-ef][1,3]dithiocin System
Authors: Kamada Toshihiro , Gama Yasuo , Wasada Nobuhide
Published: July 2006

The titled new pericyclized naphthalene system has been prepared in four steps from 1,8-naphthalenedicarboxylic anhydride in an overall yield of 35–78%. The key step in the synthesis employed a dithioacetal-cyclization reaction of 1,8-bis(mercaptomethyl)naphthalene with carbonyl compounds using boron trifluoride etherate as a catalyst.
The Selectivity of Sulfided NiW/Al2O3 Catalyst in the Hydrodesulfurization of Dibenzothiophene
Authors: Nagai Masatoshi
Published: July 2006

The selectivity of a sulfided NiW/Al2O3 catalyst for hydrodesulfurization has been studied at 300 °C and 10.1 MPa total pressure. The presence of oxygen and sulfur compounds depressed the desulfurization of dibenzothiophene, but not the hydrogenation. The addition of large amounts of acridine improved the catalytic activity significantly for the desulfurization of dibenzothiophene to biphenyl while preventing hydrogenation.
Isomerization of 1-Butene on High-Temperature-Chlorinated Alumina
Authors: Ayame Akimi , Sawada Goro
Published: July 2006

Regarding aluminas chlorinated at 973–1223 K, which have only a Lewis acidic character without hydroxyl groups and basic sites, the IR spectra of the adsorbed 1-butene were measured and the isomerization of 1-butene and cis-2-butene was performed at 273–323 K. The obtained results were compared with those for aluminas dehydrated at the same temperatures. The IR spectra of the adsorbed 1-butene well resembled that of cis-2-butene, including the absence of peaks due to double-bond and π-allyl carbanion species, observed even after outgassing at 473 K. During isomerization at 273 K, the initial isomerization reaction rates and cis/trans ratios were greater than those for dehydrated alumina. The ratio decreased rapidly with increasing reaction temperature. The specific reaction rates and the ratio were independent of the chlorination temperature. In the isomerization of cis-2-butene the most thermodynamically unstable molecule, 1-butene, was formed preferentially. The obtained results could be interpreted by an isomerization mechanism through a doubly bonded intermediate, i.e., the allylic butenyl cation.
Intramolecular [2+2] Photocycloaddition. 5. Synthetic Methods toward [2.n]-, [3.n]-, and [4.n]Naphthalenophane Skeletons by Using α,ω-Bis(vinylnaphthyl)alkanes
Authors: Nishimura Jun , Takeuchi Motoharu , Takahashi Hideo , Ueda Eiji , Matsuda Yasuhiro , Oku Akira
Published: July 2006

[2+2] Photocycloaddition, cationic cyclocodimerization, and reductive ring enlargement were developed for the syntheses of [2.n]-, [3.n]-, and [4.n]naphthalenophanes, respectively, from α,ω-bis(vinylnaphthyl)alkanes as a single starting material. Using the exclusive syn selectivity of the former two methods, the room required for the intraannular naphthalene-ring rotation in the ring system is determined.
Polymorphism and Crystal Structure of Chiral Smectogenic 4′-Heptyloxy-4-biphenylyl p-[(S)-2-Methylbutyl]benzoate
Authors: Hori Kayako , Ohashi Yuji
Published: July 2006

Two crystal forms 1 and 2 were found for the title compound. DSC measurements showed that the two crystals transform to different mesophases (Sm* I and Sm* J). Crystal data. 4′-Heptyloxy-4-biphenylyl p-[(S)-2-methylbutyl]benzoate, 1, Mr=458.61, C31H38O3, monoclinic, P21, T=298 K, a=15.065(3), b=45.59(2), c=5.636(1) Å, β=95.51(2)°, V=4109(2) Å3, Z=6, dx=1.118 Mg m−3, μ=0.475 mm−1, F(000)=1488; 2, triclinic, P1, a=13.37(2), b=22.96(2), c=10.213(5) Å, α=105.55(5), β=105.22(6), γ=102.31(9)°, V=2775(5) Å3, Z=4, dx=1.102 M gm−3. The crystal structure of 1 has been determined by single crystal X-ray analysis. Final R was 0.109. The crystal has a distinct layer structure similar to that of a smectic liquid crystal. Two of the three crystallographically independent molecules with extended paraffin chains have parallel arrangement, to which the third molecule with a twisted and highly disordered chain is antiparallel. The paraffin chains of the parallel molecules in a layer have close contacts with each other. Such contacts would enhance the intra-layer interaction which causes the transition to Sm* I.
Application of Flory Theory to Mixtures of Molten Tetrahydrates of Calcium and Cadmium Nitrates
Authors: Islam Nurul , Maheshwari Girija
Published: July 2006

The Flory theory has successfully been employed to predict the excess volume, viscosity of mixtures, surface tension, and the ultrasonic velocities of mixtures of molten tetrahydrates of calcium and cadmium nitrates. The agreement in the computed and the experimental values has been good. The excess volume as well as the excess adiabatic compressibility suggest maximum solute–solvent interactions at ca. 0.55 mole fraction of Cd2+.
On the Relationship between the Chemical Structure and the Carcinogenicity of Polycyclic Aromatic Compounds and Heterocyclic Nitrogen Compounds, as Studied by 13C NMR
Authors: Sakamoto Yohko , Sakamoto Yuko
Published: July 2006

The relationship between the chemical structure and the carcinogenicity of eighty polycyclic aromatic compounds and heterocyclic nitrogen compounds was investigated by 13C NMR. The averaged chemical shifts of the carcinogenic polycyclic aromatic compounds were within the range from δ 126.80 to 127.87, while those of the carcinogenic heterocyclic nitrogen compounds were within the range from δ 129.48 to 132.12. The carcinogenicity of several compounds were predicted according to the index.
Synthetic and Spectroscopic Studies of Xanthato-Bridged Heterobimetallic Complexes Containing Diamagnetic and Paramagnetic Metal Ions
Authors: Singh Nanhai , Singh Nand Kishore , Kaw Chetna
Published: July 2006

A series of heterobimetallic complexes of the form M[M′(Etxant)3] and M[M′(Etxant)3]2 have been prepared by the reaction of K[M′(Etxant)3] [M′=Ni(II), Cd(II), or Pb(II)] and metal nitrate or sulfate [Ma=Co(II), Ni(II), Cd(II), Tl(I), Pb(II), or Ag(I), Etxant=ethylxanthate]. These complexes have been characterized by elemental analysis, molecular weight, molar conductance, magnetic susceptibility, (1H, 13C) NMR, electronic, and infrared spectral studies. Magnetic moment and electronic spectral data indicate square planar geometry around Co(II) or Ni(II), except Tl[Ni(Etxant)3] in which Ni(II) is octahedrally coordinated. NMR spectra of M[M′(Etxant)3]2 clearly indicate the presence of two different ethylxanthate moieties, one attached to the diamagnetic Ni(II), Cd(II), or Pb(II) and the other to the paramagnetic Co(II) centre. Electrical conductance values indicate their nonelectrolytic behavior. Interaction of heterobimetallic complexes with different solvent have been studied and solvent characteristics (donor number, dielectric constant, EB (electrovalent) and CB (covalent) parameters) have been related to the structural properties of the complexes. On the basis of these studies, monomeric structure for M[M′(Etxant)3]2 and polymeric structure for M[M′(Etxant)3] have been suggested.
Ion Association of Tetrabutylammonium Halides in 1,1- and 1,2-Dichloroethane and 4-Methyl-2-pentanone
Authors: Kusakabe Satoshi , Shinoda Masahiro , Kusafuka Kaoru
Published: July 2006

The ion-association equilibrium of tetrabutylammonium chloride, bromide, and iodide in the titled solvents has been investigated by solvent extraction at 298 K. In each solvent the association constants have been found to be of similar magnitude among these three salts. This is explained in terms of the larger degree of hydration in the smaller anions. The influence of coextracted water on the equilibrium is discussed.
Interaction of Sodium Dodecyl Sulfate with Pig Serum Low-Density Lipoprotein
Authors: Yano Yuki , Takagi Toshio , Janado Masanobu
Published: July 2006

The interaction of sodium dodecyl sulfate (SDS) with the pig serum low-density lipoprotein (LDL) showed a subtle dependence on the SDS concentration. At the SDS concentrations below 0.01%, the binding isotherm conformed to the Langmuir’s type, from which the maximum number of the binding site and the intrinsic binding constant were respectively estimated to be 1600 mol mol−1 and 6.5×103 (mol dm−3)−1. At the SDS concentrations at or above 0.03%, the LDL structure irreversibly dissociated.
Reactivity of RuCl3(EPh3)2S (E=P, As; S=DMSO, DMF, THF, CH3CHO, CH3CN, CS2, (CH3)2CO) towards 2,4,6-Trichloro-1,3,5,2,4,6-trithiatriazine and Substitution Reactions of Ru(NS)Cl3(EPh3)(E′Ph3)(E=P, As; E′=P, As, Sb) with N-Donor Heterocyclic Ligands
Authors: Gupta Minu , Seth Jyoti , Agarwala UC
Published: July 2006

2,4,6-Trichloro-1,3,5,2,4,6-trithiatriazine, N3S3Cl3, reacts with Ru(III) complexes of the type RuCl3(EPH3)2S to form an intermediate which further reacts with PPh3, AsPh3, and SbPh3 to form Ru(NS)Cl3(EPh3)2 or Ru(NS)Cl3(EPh3) (E′Ph3). Besides, substitution reactions of Ru(NS)Cl3(EPh3)2 and Ru(NS)Cl3(EPh3)(E′Ph3) with pyridine, γ-picoline, pyrazine, and pyrazole have been carried out. The compounds were characterized by physicochemical methods.
Extraction and Spectrophotometric Determination of Rhenium(VII) with Thiocyanate and Amides
Authors: Mishra Neera , Sinha S K , Patel K S , Mishra R K
Published: July 2006

A new spectrophotometric method for determining rhenium with thiocyanate and organic reagents such as amides, thioamide and hydrazide over 2.0–6.0 mol dm−3 H2SO4 is described. The molar absorptivity of the complexes in the organic solvents are (2.57–3.01)×104 1 mol−1 cm−1 at absorption maximum. Of these, N-phenylacetamide (PAA) has been chosen for detailed studies. The detection limit of the method with PAA is 0.03 μg Re cm−3. The effect of kinds of acids, solvents or reagents and of diverse ions is discussed.
Thermodynamic Properties of Solution of Nonspherical Molecules Determined from Gas-Liquid Chromatography and Calculated by the Scaled Particle Theory Using the Kihara Potential
Authors: Fujiwara Hideaki , Ohtaku Ikuji , Miyagi Rieko , Sasaki Yoshio
Published: July 2006

The free energies, enthalpies, and entropies of solution have been determined for nonspherical molecules by gas-liquid chromatography and the data are discussed on the basis of a simple theory of solution, the scaled particle treatment. The solutes used are normal alkanes from pentane to decane and the solvents used are 10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5-one (DDCO), 9-heptadecanone (HPDN), and squalane. Some basic equations are derived for the nonspherical molecules by regarding the alkane solutes, HPDN and squalane as spherocylinders and DDCO as a disk and by incorporating the Kihara potential in estimating the nonspherical interactions. The enthalpies and entropies observed can be reproduced fairly well by assigning appropriate values of the sizes and potential constants for the solutes as well as for the solvents. However, these two properties tend to cancel each other in yielding the free energies, and the free energies are not reproduced so well as the enthalpies and entropies separately are. The presence of long alkyl chains in HPDN and squalane needs be allowed for better prediction of the entropies and, especially, the free energies. The present method of calculation is also applied to a spherical solute of tetramethyltin in the solvents of HPDN and DDCO with reasonable results. In this way, a relatively simple treatment of the scaled particle theory and the Kihara potential is shown to be fruitful in discussing the thermodynamic properties of solution for nonspherical molecules.
Synthetic Inorganic Ion-Exchange Materials. LI. Synthesis, Characterization, and Thermal Decomposition of Cubic Ammonium Molybdate
Authors: Khan Abdul Jabbar , Tsuji Masamichi , Abe Mitsuo
Published: July 2006

A crystalline cubic ammonium molybdate (CAM) was synthesized by the reaction of hexaammonium heptamolybdate and HNO3 at 60 °C. The X-ray diffraction pattern showed a body-centered cubic structure with crystal lattice of 12.94±0.005 Å. Ammonia free molybdic acid was not obtained even at high acid concentration. CAM contains both exchangeable and structural ammonium ions. On the basis of chemical and thermal analyses and amount of exchangeable H+, the empirical formula of the H+ form of CAM referred to [H0.68(NH4)2]O1.34·14.16MoO3·6.92H2O. CAM was found to be stable at relatively high acid concentration and temperature, and was suitable for column operations by grading to the desired mesh size.
Intermolecular Interactions of Fluorine Atoms in the Crystal of 1,3-Dimethyl-5-fluorouracil and Its Mixed Crystal with 1,3-Dimethyluracil
Authors: Taga Tooru , Yamamoto Noriko , Machida Katsunosuke
Published: July 2006

A crystal of 1,3-dimethyl-5-fluorouracil can be used to solve large amounts of 1,3-dimethyluracil as a solid–solution crystal. The crystal structure has been determined by an X-ray method. The planar molecules are arranged in a parallel sheet, and the molecules within the same sheet interact with each other through short CH···O and CH···F contacts. The short intermolecular C···F distance is 2.999(6) Å. The stability of a mixed crystal could be explained in terms of intermolecular interactions around the fluorine atom.
Photochemical Hydrogen Abstraction Reactions of 9,10-Dihydro-9,10-o-benzenoanthracene-1,4-dione Derivatives with Xanthene: Intramolecular Charge Transfer Quenching
Authors: Kitaguchi Nobuya
Published: July 2006

Intramolecular charge transfer interaction in triptycene system was investigated. 9,10-Dihydro-9,10-o-benzenoanthracene-1,4-dione (triptycenequinone) and its analogs were readily photoreduced with xanthene to give the corresponding hydroquinones and the adducts with two xanthenyl radicals. The chemically induced dynamic nuclear polarization examination and the corresponding thermal reaction proved the adducts to be originated from free radical coupling of xanthenyl radicals and quinones. The quantum yield for disappearance of the quinones depended upon both the substituents and solvents. Kinetic analysis by applying Stern–Volmer plot, using anthracene as a quencher, revealed that the quantum yield of intersystem crossing and the lifetime of the triplet state decreased with increasing electron-donating power of the aromatic rings in triptycenequinones. These solvent and substituent effects suggest that intramolecular charge transfer quenching of both the singlet and the triplet excited states of quinones by neighboring aromatic rings occurs in the triptycenequinone system. Such intramolecular charge transfer interaction would lower the rate constants of hydrogen abstraction reaction from xanthene via the triplet states of triptycenequinone derivatives.
Photochromic Properties of a New Spirobenzothiopyran Compound
Authors: Tamura Shin-ichiro , Asai Nobutoshi , Seto Jun’etsu
Published: July 2006

Photochromic processes of 1′-hexyl-5′,8-dimethoxy-3′,3′-dimethyl-6-nitrospiro[2H-1-benzothiopyran-2,2′-indoline] were investigated with laser flash techniques. Photocoloration was found to proceed via the excited singlet state, and the quantum yield of coloration was an order of magnitude smaller than those of ordinary spirobenzopyrans. The main route of the decoloration was found to be the thermal reaction. Remarkably different solvent effects for the thermal fading rate of the colored form were observed, which indicates that the zwitterionic structure is more significant for the new spirobenzothiopyran than ordinary spirobenzopyrans. Repetitive cycles of photocoloration and thermal fading were achieved.
Lipid-Coating on Polyamide Microcapsules Having Long Alkyl Chains and the Characterization of the Lipid-Coated Surface
Authors: Kono Kenji , Kimura Shunsaku , Imanishi Yukio
Published: July 2006

Polyamide microcapsules with diameters in the range of 1–5 μm were prepared by interfacial polycondensation between terephthaloyl dichloride and a mixture of l-lysine and piperazine. The carboxyl groups of l-lysine residues involved in the polyamide microcapsules were reacted with alkylamine by using water-soluble carbodiimide as a coupling reagent. The alkylated polyamide microcapsules were incubated with liposome to have the surface of the polyamide microcapsules coated with lipid bilayer membrane. The amount of lipid assemblies adsorbed on the polyamide microcapsules with octyl chains increased up to 1.5 times as much as that on the polyamide microcapsules without octyl chains. The synthetic glycopeptides were introduced to the lipid membrane adsorbed on the surface of the polyamide microcapsules. Interactions of the glycopeptides with the lipid membrane on the polyamide microcapsules and of the glycopeptides in the lipid membrane on the polyamide microcapsules with lectin were investigated.
The X-Ray Photoelectron Spectra of 1:1 and 1:2 Salts Formed from Triethylammonium and 7,7,8,8-Tetracyanoquinodimethane
Authors: Okubo Jun , Hoshi Toshihiko , Ono Isao , Karube Kaori , Kobayashi Michio
Published: July 2006

The X-ray photoelectron spectra of the 1:1 and 1:2 salts formed from the triethylammonium cation (TEAH+) and 7,7,8,8-tetracyanoquinodimethane (TCNQ) have been measured and analyzed in order to investigate the electronic structures and conformations of the salts. The N 1s band (398.2 eV) degenerated in the free TCNQ molecule splits into two bands (398.4 eV and 400.3 eV) in the 1:1 salt. This is due to the unequal interactions of the nitrogen atoms of the TCNQ anion radical (TCNQ\ewdot) with TEAH+. In the 1:2 salt, the degenerated N 1s bands of two free TCNQ molecules split into three bands (398.5, 400.0, and 401.8 eV). This implies that the negative charge is inhomogeneously distributed over two TCNQ molecules, supporting the idea that the electronic structure of the 1:2 salt can be represented approximately as TEAH+–TCNQ\ewdot–TCNQ0. It is found that, in the 1:2 salt, the neutral TCNQ molecule (TCNQ0) is weakly bound to the TCNQ anion radical (TCNQ\ewdot) of the strongly bound 1:1 salt, with their molecular planes parallel.
Preparation of Poly(phenylene sulfide)s: Polymerization of Aromatic Disulfides with Lewis Acids
Authors: Yamamoto Kimihisa , Yoshida Shu , Nishide Hiroyuki , Tsuchida Eishun
Published: July 2006

Poly(p-phenylene sulfide) is prepared through the polymerization of diphenyl disulfide with various Lewis acids, such as AlCl3 and SbCl5. Thiophenol also yield poly(p-phenylene sulfide) through its oxidation to diphenyl disulfide in the presence of an oxidizing agent or electrolysis during polymerization. Alkyl-substituted diphenyl disulfides are polymerized with a Lewis acid to efficiently yield alkyl-substituted poly(p-phenylene sulfide)s such as poly(2-methyl-, 2,6-dimethyl-, and 2,6-diethylphenylene sulfide)s, with high molecular weight and solubility in common solvents.
A Convenient Synthesis of Naphtho[1,2-b]furans
Authors: Kang Wen-Bing , Sekiya Takashi , Toru Takeshi , Ueno Yoshio
Published: July 2006

Acid-catalyzed reductive cyclization of 2-alkylsubstituted 3-ethylthio- and 3-phenylthio-1,4-naphthoquinones gave naphtho[1,2-b]furans in high yields.
Gravimetric Determination of Nickel with Salicylaldehyde Thiosemicarbazone
Authors: Laly S , Parameswaran Geetha
Published: July 2006

A study of the use of salicylaldehyde thiosemicarbazone (STSC) in the gravimetric determination of nickel is reported. STSC reacts with Ni(II) in aqueous medium in the pH range 6.5–8.2 to form reddish brown water insoluble complex. The complex can be conveniently filtered at the pump using a G4 sintered glass crucible and dried at 100–120 °C and weighed as Ni(C8H8N3OS)2. Interference of foreign ions were examined. The influence of concentration, temperature, and pH on the precipitation were studied. The reagent tested in this work was compared with classical 1,2-dioximes used in the gravimetric determination of nickel. This method was applied to determine nickel in stainless steel.
Electrochemical Studies of the Reduction Mechanism of Tetrazolium Salts and Formazans
Authors: Umemoto Kisaburo
Published: July 2006

The electrochemical study clarified that ditetrazolium salts are reduced not only to the half-reduced “monoformazans” but also to the fully-reduced “diformazans” at the potential where the first electron is transferred to generate the “tetrazolinyl radical”. The key reaction leading to the simultaneous generation of mono- and diformazans was the disproportionation reaction of the tetrazolinyl radicals. The identification of absorption spectra of reaction intermediates was performed at several reaction stages.
NAD(P)+–NAD(P)H Models 70. Reduction of Imines with Hantzsch Ester in the Presence of Silica Gel
Authors: Fujii Masayuki , Aida Tetsuo , Yoshihara Masakuni , Ohno Atsuyoshi
Published: July 2006

Imines are reduced into the corresponding amines in high yields by Hantzsch ester in the presence of silica gel. The reduction shows high chemoselectivity and stereoselectivity. Reduction of α,β-unsaturated imines proceeds with high regioselectivity to yield allylic amines (1,2-reduction products).
Splitting of 1H NMR Signal of Long Methylene Chain with Various Terminal Substituent in Aromatic Solvent
Authors: Hoshino Takashi , Imamura Yoshio
Published: July 2006

The splitting of the methylene peaks in 1H NMR spectra was studied for alkyl compounds with various substituents in 1-chloronaphthalene solutions. The solvent shifts for the higher field split methylene peak and the α-methylene peak varied with a dependence on the magnitude of the electric group moment of the terminal substituent; those for the lower- and middle-field split methylene peaks and the terminal methyl peak remained constant. It was found that the different behaviors of the solvent shifts of the methylene signals could be ascribed to the origin of the peak splitting observed for long alkyl compounds.
Triethylamine-Mediated Generation of a Synthetic Equivalent of Parent Azomethine Imine by Condensation of Ethyl 3-Benzylcarbazate with Paraformaldehyde
Authors: Kanemasa Shuji , Tomoshige Naoki , Wada Eiji , Tsuge Otohiko
Published: July 2006

A synthetic equivalent of parent azomethine imine is accessible by simple heating of ethyl 3-benzylcarbazate with paraformaldehyde under reflux in toluene in the presence of triethylamine, which effectively suppresses the undesired formation of imine dimers. The resulting imines can be trapped with a variety of dipolarophiles.
Stereocontrolled Reduction of 2-(p-Tolylsulfinyl)cycloalkanones under Basic Conditions: π-Facial Selection in Cyclic Systems Directed by a Chiral Side Chain
Authors: Ogura Katsuyuki , Ishida Michio , Fujita Makoto
Published: July 2006

Reduction of a 2-(p-tolylsulfinyl)cycloalkanone with sodium borohydride in methanol–triethylamine is accompanied by rapid epimerization at C2. Under the conditions employed here, the π-facial selectivity of the reduction is directed by the side chain chirality and, among four possible isomers of the corresponding cycloalkanol, one isomer is given with high selectivities up to 85%.
Stereoselective Bromination of Acetylenes with Bromine in the Presence of Graphite
Authors: Kodomari Mitsuo , Sakamoto Takaaki , Yoshitomi Suehiko
Published: July 2006

Acetylenes were stereoselectively brominated with molecular bromine adsorbed on graphite in dichloromethane to produce (E)-α,β-dibromoalkenes; isomerization of the E-isomer to the Z-isomer, usually catalyzed by bromine, did not occur in the presence of graphite.
On the Existence of NaC2O4− Ion Pair Complex
Authors: Singh Raj Pal
Published: July 2006

Existence of NaCO4− ion pair complex formation in solutions has been further documented through the solubility measurements of calcium oxalate monohydrate in sodium chloride, magnesium chloride, and mixtures of sodium and magnesium chlorides.
Surface Adsorption and Micelle Formation of Dodecyltrimethylammonium Chloride and Decylammonium Chloride Mixture
Authors: Ikeda Norihiro , Shiota Eiji , Aratono Makoto , Motomura Kinsi
Published: July 2006

The surface tension of the aqueous solution of dodecyltrimethylammonium chloride (DTAC) and decylammonium chloride (DeAC) mixture was measured as a function of the total molality and composition of the surfactants at 298.15 K under atmospheric pressure. To make clear the miscibility of surfactants, the compositions in the mixed adsorbed film and micelle were calculated by use of the thermodynamic equations developed previously. The results indicated that both adsorbed film and micelle are richer in DTAC molecules than the bulk solution. Furthermore, the composition in the adsorbed film at the critical micelle concentration (cmc) was evaluated and compared with that in the micelle. It was found that the composition of DeAC in the micelle is smaller than that in the adsorbed film. This forms a striking contrast to the previous observation of dodecylammonium chloride (DAC)–DeAC mixture. It was concluded that the structure and size of polar head group of surfactants have a significant influence on the miscibility of surfactants.
Aggregation of Complexes Coordinated with N,N′-Bis(5-alkylsalicylidene)ethylenediamine: 1H NMR Peak Shifts and Paramagnetic Broadening Investigations
Authors: Miyamura Kazuo , Satoh Keiki , Gohshi Yohichi
Published: July 2006

Nickel(II) complexes coordinated with N,N′-disalicylideneethylenediamine (salen) substituted by a series of n-alkyl side chains have been synthesized. Drastic improvement in the solubility towards chloroform brought about by the increase in alkyl side chain lengths realised an extremely high concentration of 0.5 mol·dm−3. Due to aggregation, their 1H NMR spectra in CDCl3 were strongly dependent on the concentration especially in the high concentration region. The alkyl chain length has very little influence on the dependency, indicating that the aggregation is caused by the complex–complex interaction rather than by the hydrophobic interaction between the alkyl side chains. Assuming a monomer–dimer equilibrium, the aggregation constant is determined from the concentration dependence. Further, the structure of the aggregate is estimated by combining the results of the concentration dependence, and the paramagnetic broadening caused by adding the corresponding copper(II) complex. The paramagnetic broadening investigation also indicated a close contact of copper(II) complex to nickel(II) complex.
Selective Synthesis of Halogeno Derivatives from 5-Acetoxytropolone
Authors: Nagao Tomohiro , Mori Akira , Takeshita Hitoshi
Published: July 2006

5-Acetoxytropolone was successfully halogenated by means of benzyltrimethylammonium tribromide and sulfuryl chloride to give 3-halotropolones and 3,7-dihalotropolones which were converted to the corresponding halogenated p-tropoquinone derivatives. From 3,7-dihalo-p-tropoquinones, 3,4,7-trichloro-5-hydroxytropolone was prepared in good yields via a Thiele-type addition reaction with hydrochloric acid. By a similar treatment, 5-hydroxytropolone gave a complex mixture.
The Phase Transitions of 1,4-Dialkyl-1,4-diazoniabicydo[2.2.2]octane Bis(tetrafluoroborate), Cn–DABCO–Cn–(BF4)2 (10≤n≤22)
Authors: Terada Tohru , Nogami Takashi , Shirota Yasuhiko
Published: July 2006

The phase transitions of a series of title compounds were investigated by means of DSC, IR absorption spectra, and measurements of ionic conductivities. All of the compounds exhibited phase transitions in the range of 77–110 °C. The IR absorption spectra clarified that conformational change in the alkyl chain occurred above the transition temperature. The temperature dependences of the ionic conductivities of BF4− showed conductivity jumps by a factor of 9–120 around the transition temperatures. A comparison of the DSC results and the ionic conductivities of BF4-salts with those of the corresponding Br-salts showed that the former compounds have higher transition temperatures, smaller transition enthalpies (and, accordingly, smaller transition entropies), and smaller values of the conductivity jumps than the latter. These results show that BF4-salts are more rigid than Br-salts in the low temperature phase and that the motion of the alkyl group of the former salts is less vigorous than the latter in the high-temperature phase. By observing the crystal with a polarization microscope under crossed Nicols condition, it was found that optical anisotropy was diminished gradually with the elevation of the temperature and disappeared completely above Tc without changing the crystal shape.
Study on Conjugated Redox Membranes Containing an Intercellular Component of Wool as an Electron Carrier
Authors: Nakamura Yoshiharu , Kamon Noriaki , Hori Teruo
Published: July 2006

To realize artificially such a conjugated redox reaction as that which is drived across the biological cell membrane, two enzymic redox reactions were conjugated across a hydrogel membrane prepared with urethane prepolymer holding stabilized isocyanate groups. As redox couples, glucose 6-phosphate (G6P)/glucose 6-phosphate dehydrogenase (G6PD)/gluconolactone 6-phosphate (GL6P) and glutathione oxidized form (GSSG)/glutathione reductase (GRD)/glutathione reduced form (GSH) were chosen together with their common coenzyme, NADP+/NADPH. The driving of a system consisting of two redox couples separated with the hydrogel membrane containing the coenzyme NADP+ was intiated by the reduction of NADP+ on the membrane surface in contact with the G6PD/G6P solution. The conjugated redox reaction proceeded by electron exchange between coenzymes in the membrane and the reproducing of NADP+, which was accompanied with the GRD/GSSG solution. The rate of electron transfer across the urethane membrane was markedly accelerated by incorporating a nonkeratinous intercellular cement compound extracted from wool into the membrane. From cyclic voltammograms of a methyl viologen mediator, using a bare electrode and an intercellular compound modified carbon electrode, it was confirmed that the intercellular component could surely act as a good electron carrier.
The Relationship between the Acoustic Property and the Hydration of Saccharides
Authors: Uedaira Hisashi , Ishimura Miyuki
Published: July 2006

Values of the relative increment of the sound velocity, A, in aqueous solutions of sugars were calculated from the experimental sound velocities. The values of A correlated well with the mean number of equatorial OH groups in a sugar molecule.
Gamma-X Ray Coincidence Mössbauer Study with FeSO4·7H2O(57Co)
Authors: Kobayashi Takayuki
Published: July 2006

The anomalous charge states formed after the EC decay of 57Co in FeSO4·7H2O doped with 57Co are investigated in detail using the gamma-X ray coincidence Mössbauer spectroscopy. The mechanism to form these states is explained in terms of the H2O and SO42− coordination shells around the decaying atom.
A Facile Reductive Removal of Bromine Atom(s) of 6,6-Dibromo- and 6-Bromopenicillanate Derivatives in a Pb/Al Bimetal System
Authors: Tanaka Hideo , Tanaka Motoaki , Nakai Akira , Katayama Yasumi , Torii Sigeru
Published: July 2006

Reductive removal of the bromine atom(s) of 6,6-dibromo- and 6-bromopenicillanate 1-oxides has been performed successfully on treatment with aluminum metal in the presence of a catalytic amount of lead(II) bromide in methanol containing 1% aqueous hydrobromic acid. In a similar manner, 6,6-dibromopenicillanates and their 1,1-dioxides can be convened to the corresponding debromination products, respectively.
Asymmetric Radical Reaction in the Coordination Sphere. IV. Ruthenium(II)-Catalyzed Asymmetric Addition of Sulfonyl Chloride to 1-Phenylpropene
Authors: Kameyama Masayuki , Kamigata Nobumasa
Published: July 2006

The asymmetric addition of methane- and p-toluenesulfonyl chloride to 1-phenylpropene catalyzed by Ru2Cl4[(−)-diop]3 affords optically active 1:1 adducts, (+)-(1R,2RS)-1-chloro-2-methylsulfonyl-1-phenylpropane (2) and (+)-(1R,2RS)-1-chloro-1-phenyl-2-tosylpropane (3), with about 13–19%ee. Similarly, (−)-(1S,2RS)-2 and (−)-(1S,2RS)-3 were obtained when Ru2Cl4[(+)-diop]3 was employed. A enantiolace differentiation is considered to occur in the chlorine atom transferring step from the ruthenium(III) species to the carbon radical in the coordination sphere.
The Preparation and Structure of the Copper(II) Chloride Complex of 5,5′-Carbonylbis[1,3-dimethyl-3,4,5,6-tetrahydro-1,3,5-triazin-2(1H)-one]
Authors: Ebisuno Toichi , Takimoto Michiaki , Takahashi Miyuki , Shiba Ryuichi
Published: July 2006

A new 1,3-dimethylurea–formaldehyde condensate like a crown compound with two rings, 5,5′-carbonylbis[1,3-dimethyl-3,4,5,6-tetrahydro-1,3,5-triazin-2(1H)-one], was prepared. The molecular structure of the complex with the condensate and copper(II) chloride (1:1) was determined by means of X-ray analysis. The copper(II) ion was coordinated intermolecularly between two oxygen atoms (O(2) and O(2)′ in the adjacent molecule).
The Meaning of the Equilibrium Spreading Pressure of Fatty Acid Being Relatively Soluble in an Underlying Subphase
Authors: Iwahashi Makio , Iiduka Kimiyo , Watanabe Takashi , Seimiya Tsutomu
Published: July 2006

The spreading pressure of a lipid monolayer in equilibrium with its crystal placed at the air/water interface is a thermodynamical property—i.e., the equilibrium spreading pressure (ESP). It is, however, quite likely that the apparently constant spreading pressure of a lipid with a relatively large desorption rate into the underlying subphase is not a thermodynamical property but merely a steady-state one. Mutual comparisons were, therefore, carried out for the rate constants of the six possible processes associated with the spreading pressure of tetradecanoic acid, whose monolayer has a relatively large desorption rate into the underlying subphase; it was found that monolayer formation from its crystal was predominant and that the desorption from the monolayer little affected the spreading pressure, even at high temperatures. Consequently, the apparently constant spreading pressure for the tetradecanoic acid can be regarded as the ESP even at high temperatures, in which the dissolution of the monolayer into the subphase occurs very rapidly.
Parametrized Equations-of-Motion Method at the (1p-1h)+(2h-2p) Level and Its Application to Linear Polyenes
Authors: Shibuya Tai-ichi , Funada Tadashi , Narita Susumu
Published: July 2006

The previously proposed idea of parametrizing the equations-of-motion method [Int.  J. Quantum Chem., 18, 205 (1980)] has been worked out for the π→π* transitions of linear polyenes. The excitation operator consists of not only 1p-1h creation and annihilation operators but also 2p-2h creation and annihilation operators. [Bull. Chem. Soc. Jpn., 61, 1103 (1988)]. The proposed scheme accounts for the effect of σ→σ* mixings in contrast with the traditional pi-electron theories. In the present work, the two-center Coulomb integrals are evaluated by 1/R, and all the one-center integrals on the C atom are assumed to be the same. Values of the three parameters (a, b, ζ) introduced in the scheme are so determined that the computed excitation energies of ethylene and s-trans-butadiene fit the observed values. The scheme has been applied to a series of all-s-trans linear polyenes through dodecahexaene. Some notable results are: (1) The σ→σ* mixings play a significant role in lowering the excitation energies of the allowed transition to 11Bu; (2) the 21Ag state is of Ag− type and almost free from this effect; (3) double excitations (2p-2h states) are dominant in the 21Ag state but practically negligible in the 11Bu state.
Preparation of μ-Cyano Dinuclear Chromium(III) Complexes MI[F(en or tn)2Cr(NC)Cr(CN)5] from the Doubly Complexed Salts of the Form MI[CrF(H2O)(en or tn)2][Cr(Cn)6]
Authors: Johda Makoto , Suzuki Masatatsu , Uehara Akira
Published: July 2006

Preparation of the μ-cyano dinuclear complexes MI[F(en or tn)2Cr(NC)Cr(CN)5]·nH2O from the double complexes MI[CrF(H2O)(en or tn)2][Cr(CN)6]·nH2O was carried out both in the solid state and in solution, where MI is Li+, Na+, K+, or Rb+ ion; en and tn stand for 1,2-ethanediamine and 1,3-propanediamine, respectively. The desired μ-cyano dinuclear complexes were successfully obtained in solution, but the mixture of di- and trinuclear complexes was formed along with unknown polymeric species in the solid state. The electronic spectra of the dinuclear complexes exhibited a small but clear band due to spin-forbidden transition (4A2g→2Eg). Magnetic moments of the dinuclear complexes were 3.4–3.5 μβ at ambient temperatures and 2.2–2.4 μβ at 80 K, which are substantially smaller than the spin-only value (3.87 B.M.). The J values for the dinuclear complexes were estimated to be −19–−20 cm−1, indicating that an antiferromagnetic superexchange interaction is exerted between two chromium(IH) ions through μ-CN group, but the magnitude of the interaction is smaller than that of the μ-oxo complexes (J=−450 cm−1) and comparable to that of the μ-hydroxo complexes (J=−23 cm−1) reported previously.
Studies on Mixed Chelates. XVII. Crystal Structure and Spectral Properties of Mixed Nickel(II) Nitrate Complexes Containing 1,2-Dipiperidinoethane and β-Diketonate Ligands
Authors: Fukuda Yutaka , Fujita Chiori , Miyamae Hiroshi , Nakagawa Hiroko , Sone Kozo
Published: July 2006

Several new mixed nickel(II) nitrate complexes with 1,2-dipiperidinoethane (dipe) and β-diketonate ions (dike), [Ni(NO3)(dike)(dipe)], have been obtained and characterized. The crystal structure of one of them, [Ni(NO3)(acac)(dipe)], was determined by X-ray crystallography. The crystal is monoclinic with the space group Cc, Z=4, a=9.0517(4), b=21.932(1), c=9.8814(6) Å, β=88.151°. Block-diagonal least-squares refinements have led to a final R value of 0.036 for 2471 reflections. It was confirmed that the nitrate ion in the octahedral complex acts as a bidentate ligand and that the conformation of the piperidine ring in dipe is a chair form. The spectral behaviors of these complexes in various organic solvents are discussed in comparison with those of similar complexes with other N,N′-alkylated ethylenediamine ligands (diam). It was concluded that, in a solvent with low polarity, the complexes are dissolved unchanged; in a more polar solvent, however, dissociation of NO3− takes place, producing solvated or unsolvated cationic species ([Ni(dike)(diam)(Solvent)2]+ (Oh) or [Ni(dike)(diam)]+ (Square Planar)) according to the donor and acceptor properties of the solvent.
Base-Catalyzed Isomerization and Racemization Reactions of [Co(L1)(L2)]Type Complexes (L1=Iminodiacetato or N-Methyliminodiacetato and L2=3-Azapentane-1,5-diamine or 3-Methyl-3-azapentane-1,5-diamine)
Authors: Kawaguchi Hiroshi , Shimizu Masato , Ama Tomoharu , Yasui Takaji
Published: July 2006

The isomerization and racemization reactions of the [Co(ida)(dien)]+ and [Co(ida)(mdien)]+ systems were studied in an aqueous solution. The main isomerization path of the [Co(ida)(dien)]+ system was u-fac\ightleftharpoonsmer\ightleftharpoonss-fac and the rate law for each of the processes could be described as R=k[complex][OH−]. In the [Co(ida)(mdien)]+ system, there was an additional isomerization path of u-fac→s-fac. The equilibrium mole ratio of three isomers was u-fac:mer:s-fac=25:19:56% for [Co(ida)(dien)]+ and u-fac:mer:s-fac=3:3:94% for [Co(ida)(mdien)]+. In the isomerization of (+)564CD-u-fac-[Co(mida)(mdien)]+, (+)582CD-mer isomer was stereoselectively produced. The racemization mechanisms of mer-[Co(ida)(dien)]+ and mer-[Co(mida)(dien)]+ are also discussed.
The Zinc(II)-Catalyzed Henkel Reaction of Dipotassium 1,8-Naphthalenedicarboxylate in a Dispersion Medium
Authors: Fujishiro Koichi , Mitamura Shuichi
Published: July 2006

The Henkel reaction of dipotassium 1,8-naphthalenedicarboxylate in naphthalene as a dispersion medium gave dipotassium 2,6-naphthalenedicarboxylate (1) in a higher yield and with a better reproducibility than the reaction without a dispersion medium. Catalysts, particularly zinc catalysts, were examined in detail. The anion moiety of zinc catalysts affected the reaction, and the halide anion was effective for the selective formation of 1. The addition of potassium halide to the zinc catalysts also increased the yield of 1. The catalytic activity of the halide anion increased in the order; Cl−<Br−<I−. The activity of the zinc catalysts was also compared with that of cadmium catalysts.
Formation of N-Tributylstannyl Heterocycle from Bis(tributyltin) Oxide and ω-Haloalkyl Isocyanate. One-Pot Convenient Synthesis of 2-Oxazolidinones and Tetrahydro-2H-1,3-oxazin-2-one
Authors: Shibata Ikuya , Nakamura Kenji , Baba Akio , Matsuda Haruo
Published: July 2006

Novel types of compounds, N-tributylstannyl-2-oxazolidinone (4a) and tetrahydro-2H-1,3-oxazin-2-one (4b), are formed from the adduct of (n-Bu3Sn)2O (1) with ω-haloalkyl isocyanate (2), and the subsequent coupling reaction with alkyl halides gives a variety of N-substituted 2-oxazolidinones and tetrahydro-2-oxazinones in a one-pot procedure. Both the cyclization and the coupling reaction proceed quantitatively in the presence of HMPA which enhances the reactivity of the Sn–heteroatom bond by coordination.
Synthesis of Ba2YCu3O7–δ Superconductor through Organometallic Route
Authors: Hirano Shin-ichi , Hayashi Takashi , Miura Masashi , Tomonaga Hiroyuki
Published: July 2006

The chemical synthesis of a high-Tc Ba2YCu3O7–δ superconductor was investigated through the organometallic route, using Ba metal, Y(OPri)3, and Cu–alkoxides or Cu–acetylacetonate as starting materials. Chemically homogeneous submicron powders of single phase Ba2YCu3O7–δ were successfully prepared at 750 °C by controlled partial hydrolysis of metal alkoxides. The utilization of ozone for favorable decomposition of Ba2YCu3O7–δ precursors was found to have a remarkable effect on suppressing the formation of BaCO3 and lowering the formation temperature of Ba2YCu3O7–δ to about 650 °C. The single phase Ba2YCu3O7–δ ceramics exhibited superconductivity at approximately 83 K (Tc end).
Quadrupole Coupling Constants in the Symmetric Tetrasubstituted Germanes
Authors: Harazono Toshie , Tanaka Katsumi , Takeuchi Yoshito
Published: July 2006

The quadrupole coupling constants in the symmetric tetrasubstituted germanes, GeR4 (R=CH3, C2H5, n-C3H7, n-C4H9, Cl, and Br) were obtained by measuring the 73Ge spin-lattice relaxation times (T1) and the reorientational correlation times (τc) of the chloroform solutions. Quadrupole coupling constants of GeR4 were in the range of 0.72 MHz (R=n-C4H9) to 1.51 MHz (R=CH3), and these decreased slightly as the molecular radius increased.
Organic Photochemical Reactions. XXXI. Photosensitized Ring-Cleavage Reactions of 2,2-Diaryloxetanes by Aromatic Nitriles
Authors: Nakabayashi Kenichi , Kojima Jun-ichi , Tanabe Kimiko , Yasuda Masahide , Shima Kensuke
Published: July 2006

Photosensitized reactions of 2,2-diaryloxetanes by 1,4-dicyanonaphthalene, 1-cyanonaphthalene, and 9,10-dicyanoanthracene, which give such ring-cleavage products as substituted benzophenones and alkenes, have been investigated. Quantum yields for the ring cleavage vary with the substituents on both the aryl group and oxetane ring. The quantum yield increases with increase in electron-donating ability of the oxetane. The limiting quantum yields in the case of 1,4-dicyanonaphthalene-photosensitized reaction of 2,2-di-p-tolyl- or 2,2-bis(p-mechoxyphenyl)-3,3,4-uimethyloxetane exceed unity. The mechanism is discussed in terms of electron transfer from oxetanes to the excited singlet state of the sensitizer as well as the regeneration process of the oxetane cation radical involving the hole transfer from substituted benzophenone cation radicals to oxetanes in the chain process.
A Conductometric Study on the Phenylglyoxylic Acid–Strychnine Complex
Authors: Sakai Yasuzo , Sato Kenichi , Ito Ikuko , Takahashi Fujio
Published: July 2006

In order to elucidate the mechanism by which phenylglyoxylic acid (PGA) is reduced electrochemically in the presence of strychnine (SC) to form mandelic acid (MA), which exhibits an optically active property, conductometric studies were carried out. The formation of a 1:1 complex between PGA (or MA) and SC was suggested from the results that equimolar mixture of PGA (or MA) and SC showed a maximum decrease of conductivity. Equilibrium constants of the 1:1 complex of PGA–SC or MA–SC were determined from the results of conductivity measurements at various temperatures. The thermodynamic data were calculated. ΔH and ΔS were found to be +22 kJ mol−1 and +1.1×102 J K−1 mol−1 for both the PGA–SC complex and MA–SC complex.
A Least-Squares Method for Computing Rate Constants of Reversible, First-Order, Triangular Network Reactions and Its Application to the Intermolecular Rearrangements of Acetylacetonatobis(4,4,4-trifluoro-1-phenyl-1,3-butanedionato)ruthenium(III)
Authors: Hoshino Yoshimasa , Takahashi Ryouta , Shimizu Kunio , Satô Gen P , Aoki Koichi
Published: July 2006

A useful method for computing the rate constants of reversible, first-order, triangular network reactions (B1\ightleftarrowsB2, B2\ightleftarrowsB3, B3\ightleftarrowsB1) is developed. It gives the best-fit set of the rate constants from the experimental data of the equilibrium constants and the mole fraction-time curves through an iterative least-squares method. This type of reaction can be classified into three categories for different shapes of the mole fraction-time curves. The method was successfully applied to determining the rate constants of the rearrangement reactions among the three isomers of [Ru(acac)(tfpb)2] (acac−=acetylacetonate ion, tfpb−=4,4,4-trifluoro-1-phenyl-1,3-butanedionate ion) in N,N-dimethylformamide at 90 °C. The direct conversion between the de,fc-bis(tfpb) isomer and the cf,ed-bis(tfpb) isomer was forbidden. The twist mechanisms are incompatible with this fact.
Natural-Abundance Oxygen-17 Magnetic Relaxation in Aqueous Solutions of Apolar Amino Acids and Glycine Peptides
Authors: Ishimura Miyuki , Uedaira Hisashi
Published: July 2006

The spin-lattice relaxation times, T1, of H217O have been measured for the aqueous solutions of 11 apolar amino acids and 5 glycine peptides as a function of the concentration at 25°C. The coordination numbers, nh, and the rotational correlation times, τch, of water molecules around the amino acids and peptides were estimated and compared with that of pure water, τc0. The value of τch⁄τc0=1.87 for norleucine is the largest, while those of τch⁄τc0 for glycine peptides are almost the same 1.2. The value of nh(τch⁄τc0−1) was defined as the dynamic hydration number (DHN). The DHN showed a good correlation with several physicochemical properties, such as the molecular weights, partial molar volumes, adiabatic compressibilities, heat capacities, B-coefficients of the activity coefficent, and limiting diffusion coefficients of amino acids and glycine peptides in aqueous solutions.
Stereoselective Construction of Acyclic Structures with Four Consecutive Asymmetric Centers
Authors: Hanamoto Takeshi , Katsuki Tsutomu , Yamaguchi Masaru
Published: July 2006

All the eight possible diastereomers of 6,8-dihydroxy-5,7-dimethyltridecane, taken as the model example for the construction of four consecutive asymmetric centers, were stereoselectively synthesized from two common starting materials, α-hydroxy-β-methyl-γ,δ-unsaturated acids (1a and 1b), wherein a newly introduced stereoselective epoxidation of β-methylhomoallylic alcohols and the subsequent alkylative opening of epoxide rings were utilized as key steps.