bluuebunny/crossref_metadata_2025_split huggingface dataset:
Polymorphism and Crystal Structure of Chiral Smectogenic 4′-Heptyloxy-4-biphenylyl p-[(S)-2-Methylbutyl]benzoate
Authors: Hori Kayako , Ohashi Yuji 
Published: July 2006

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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.
Surface Adsorption and Micelle Formation of Dodecyltrimethylammonium Chloride and Decylammonium Chloride Mixture
Authors: Ikeda Norihiro , Shiota Eiji , Aratono Makoto , Motomura Kinsi 
Published: July 2006

Abstract
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

Abstract
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

Abstract
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.