bluuebunny/crossref_metadata_2025_split huggingface dataset:
Parity-Violating Energy Shift of Glycine, Alanine, and Serine in the Zwitterionic Forms: Calculation Using HFO-NG Basis Sets
Authors: Kikuchi Osamu , Wang Hui 
Published: July 2006

Abstract
The parity-violating energy shift, Epv, was calculated for glycine, alanine, and serine using the HFO-5G and -6G minimal basis sets, which were determined so as to well reproduce the behavior of an atomic orbital near the nucleus. A clear basis set dependence was observed in both the sign and magnitude of Epv. For the zwitterionic form of glycine, the HFO-5G and -6G calculations gave an Epv similar to that obtained by the (14,14/10) minimal basis set. For the most stable conformation of l-alanine, these basis set gave a negative Epv, indicating that l-alanine is more stable than d-alanine, while the split-valence basis sets gave positive values. It was shown that l-serine is lower in energy than d-serine due to the parity-violating interaction for almost the entire range of the C–C rotation angle.
1H NMR Studies of Motions in Solid (CH3)3CBr, (CH3)3CCl, and (CH3)3CNO2: Methyl Group and t-Butyl Group Uniaxial Reorientations
Authors: Hasebe Tooru 
Published: July 2006

Abstract
1H NMR line shapes and their second moments for t-butyl compounds {(CH3)3CX where X=Br, Cl, and NO2} have been studied as a function of temperature. It is shown that the methyl group and the t-butyl group uniaxial reorientations are distinguished by 1H NMR technique. The dipolar interactions modulated by these motions are reported in three cases: the first where methyl reorientation is fast while t-butyl reorientation is slow, the second where t-butyl reorientation is faster than methyl reorientation, and the third where both reorientations are in almost the same rate. The results obtained here are consistent with the results of 1H NMR relaxation studies reported previously.
Analysis of Molecular Motions in SiCl4 by 35Cl NQR Spectroscopy
Authors: Koukoulas Alexander A , Whitehead M A 
Published: July 2006

Abstract
The temperature dependence of the 35Cl nuclear quadrupole resonance frequencies, spin-lattice relaxation times and line widths were analyzed for the presence of a solid–solid phase transition in SiCl4. The brittle phase was verified to temperatures approaching the melting point. Evidence suggesting the formation of a plastic phase at elevated temperature is discussed.
Strong Thermochromic and Solvatochromic Effects of Ni(II) and Cu(II) Complexes in DMF/Nitromethane Mixtures: A Probe for Investigation of Binary Solvent
Authors: Bourdin D , Lavabre D , Béteille J P , Levy G , Micheau J C 
Published: July 2006

Abstract
Thermochromic and solvatochromic equilibria involving the ions [Ni(tmen)(acac)]+ and [Cu(tmen)(acac)]+ respectively are highly sensitive to the polarity of the solvent. These probes are thus suited for the study of binary mixtures. In nitromethane (NM)/dimethylformamide (DMF) binary solvent the Ni(II) complex displays strong thermochromism in a zone of low DMF concentration. This result is surprising because neither of the two solvents are intrinsically thermochromic since NM is a weak donor while DMF is a strong donor. NM/DMF binary mixtures behave like solvents with intermediate donor properties. In the same solvent mixtures (low DMF concentration), the solvatochromic behavior of the Cu(II) complex is reflected by a large shift in the maximum absorption of more than 70 nm. This was accounted for by the considerable variation in donor power of the solvent mixture in this concentration range. Quantitative analysis of the thermochromic and solvatochromic equilibria as a function of DMF concentration in NM indicated the existence of self-associations of DMF. The relatively small effects of dilution of DMF on the donor properties of the solvent mixture was explained in terms of the discharge of free DMF from self-associations with increasing dilution. In DCE, DMF self-associates to a greater extent than in NM.
Thermodynamics of Formation of Ternary (2,2′-Bipyridine)thiocyanatocadmium(II) Complexes in N,N-Dimethylformamide
Authors: Ishiguro Shin-ichi , Ozutsumi Kazuhiko , Yagasaki Atsushi 
Published: July 2006

Abstract
The formation of ternary (2,2′-bipyridine)thiocyanatocadmium(II) complexes has been studied by calorimetry in N,N-dimethylformamide containing 0.4 mol dm−3 (C2H5)4NClO4 as a constant ionic medium at 25 °C. The formation of [CdA(bpy)]+, [CdA2(bpy)], [CdA3(bpy)]−, [CdA(bpy)2]+, and [CdA2(bpy)2] (A=SCN, bpy=2,2-bipyridine) is revealed, and their formation constants, enthalpies, and entropies were obtained. The result is compared with that in the corresponding halide systems in the same solvent.
Synthesis of cis-transoid-cis- and cis-cisoid-cis-Tetracyclo[6.6.0.01,11.03,7]tetradecan-12-ones via Novel Rearrangement
Authors: Kakiuchi Kiyomi , Hirano Naoki , Shimizu Toshihiro , Suwa Mitsuhito , Kobiro Kazuya , Tobe Yoshito , Odaira Yoshinobu 
Published: July 2006

Abstract
A new type of tetracyclic compounds, cis-transoid-cis- and cis-cisoid-cis-tetracyclo[6.6.0.01,11.03.7] tetradecan-12-ones, having a tetraquinane framework, has been synthesized by the novel acid-catalyzed rearrangement.
Efficient Activation of Acetals, Aldehydes, and Imines toward Silylated Nucleophiles by the Combined Use of Catalytic Amounts of [Rh(COD)Cl]2 and TMS-CN under Almost Neutral Conditions
Authors: Soga Tsunehiko , Takenoshita Haruhiro , Yamada Masaaki , Mukaiyama Teruaki 
Published: July 2006

Abstract
In the presence of a catalytic amount of a transition metal compound such as [Rh(COD)Cl]2, Co(acac)2, or NiCl2, trimethylsilyl cyanide smoothly reacts with acetals to form α-methoxy carbonitriles in good yields. In the coexistence of catalytic amounts of [Rh(COD)Cl]2 and TMS-CN, silyl enol ethers or ketene silyl acetals react with acetals, aldehyes, or imines to yield the corresponding coupling products in good yields under almost neutral conditions.
Effect of Heat Treatment of Hydrous Metal Oxides on Their Cation-Exchange Selectivity
Authors: Yamazaki Hiromichi , Kaneda Masakadzu , Inoue Yasushi 
Published: July 2006

Abstract
The effect of a heat treatment on the ion-exchange selectivity of hydrous metal oxides was studied by measuring the distribution coefficients of Cs+, Ba2+, Co2+, and Eu3+ on hydrous oxides of TiIV, SnIV, ZrIV, and NbV. The distribution coefficients decreased with increasing temperature for the heat treatment, except on hydrous Nbv oxide, in which the reverse effect was observed (except for Cs+). The decrease in the hydrous SnIVand ZrIV oxides is ascribed to a decrease in their ion-exchange capacity. In the case of hydrous TiIV and NbVoxides, the distribution coefficients were strongly affected by a change in the acidity of the most dissociable OH groups by the heat treatment. The selectivity of the exchangers has no direct correlation with the change in the porosity, the specific surface area and the density of the materials by the heat treatment.
NMR Studies on Reorientational Motion of Hydrated D2O Molecules in Tetraalkylammonium Bromide Dilute Aqueous Solutions
Authors: Shimizu Akio , Taniguchi Yoshihiro 
Published: July 2006

Abstract
The spin-lattice relaxation times of D and 17O nuclei of hydrated D2O molecules in tetraalkylammonium bromide (Me4NBr, Et4NBr, Pr4NBr, and Bu4NBr) dilute aqueous solutions in the concentration range of 0.2 to 1.0 mol kg−1 at 25°C were measured by NMR spectroscopy. The relaxation rates of D and 17O nuclei varied linearly with increasing the concentration below 1.0 mol kg−1. The dynamic hydration number, Bx+, is defined by Bx+=(k·τx+⁄τx0−1)nx+⁄50.0, where τx+ and τx0 (X=D or 17O) are the reorientational correlation times of hydrated D2O molecules (nx+) in R4N+ (R: alkyl group) and pure D2O molecule. The Bx+ increases with increasing the alkyl chain length of R4N+ ions. The abnormally large Bx+ values, compared with those of alkali metal ions, are caused by the hydrophobic hydration around the alkyl group of the R4N+ ion. The reorientational motion of a hydrated D2O molecule in the hydration sphere of R4N+ ions is isotropic, though the motion of a D2O molecule in the ionic hydration of alkali metal ions is anisotropic.
Effect of Poly(oxyethylene) Chain Length on Electrosorption of Hexa and Octa(ethylene glycol) Mono n-Dodecyl Ethers at the Polarized Nitrobenzene–Water Interface
Authors: Kakiuchi Takashi , Usui Taketoshi , Senda Mitsugi 
Published: July 2006

Abstract
The interfacial tension at the interface between a nitrobenzene solution of 0.1 mol dm−3 tetrapentylammonium tetraphenylborate and an aqueous solution of 0.05 mol dm−3 lithium chloride has been measured as a function of the applied voltage across the interface at 25°C in the presence of hexa- and octaethylene glycol monododecyl ethers, C12E6 and C12E8, in the nitrobenzene phase. Both C12E6 and C12E8 strongly adsorbed over the entire potential range of the polarized interface. The adsorption of C12E6 and C12E8 was stabilized by complex formation with Li+ ions in the aqueous phase, as is the case of C12E4 (T. Kakiuchi, T. Usui, and M. Senda, Bull. Chem. Soc. Jpn, 63, 2044 (1990).). The difference in the standard adsorption Gibbs energies between n=6 and 8, where n is the number of oxyethylene units, was twice as large as that between n=4 and 6, indicating that a chain length longer than 6 is preferable for the complex formation with Li+ ions at the interface. The surface activities of both C12E6 and C12E8 were markedly enhanced by a positive increase in the potential of the aqueous phase with respect to the potential in the nitrobenzene phase. This dependence of adsorption on the electrical potential difference indicates that the adsorbed C12E6 and C12E8 molecules behave as cationic surfactants, owing to the complex formation at the interface.
Divalent Cation-Induced Phase Transition of Phosphatidylserine Monolayer at the Polarized Oil–Water Interface and Its Influence on the Ion-Transfer Processes
Authors: Kakiuchi Takashi , Kondo Tetsuya , Senda Mitsugi 
Published: July 2006

Abstract
The phase properties of dipalmitoylphosphatidylserine(DPPS) monolayer at a polarized nitrobenzene–water interface have been studied by measuring the double-layer capacitance of the interface, Cdl, under precise control of the potential drop across the interface. When a saturated DPPS monolayer was in contact with an aqueous 0.1 mol dm−3 LiCl solution, the Cdl took a value of 9.5 μF cm−2. The presence of Ca2+ or Mg2+ at greater than 2 mmol dm−3 in the aqueous phase induced a decrease in Cdl down to 1.5 μF cm−2, corresponding to the phase transition of the monolayer from a liquid-expanded to a condensed phase. The condensed DPPS monolayer was stable against a change in the applied potential across the interface between ΔOWφ=−0.14 and 0.10 V, where ΔOWφ is the potential of the aqueous phase with respect to that in the nitrobenzene phase. Cyclic voltammetric measurements of ion transfer showed that the DPPS monolayer in the liquid-expanded state decreased the rate of ClO4− transfer from the aqueous to the nitrobenzene phase, but did not affect the rate of tetramethylammonium ion, TMA+, transfer. This indicates the importance of the electrostatic interaction between the negatively charged DPPS monolayer and the transferring ions in determining the rate of ion transfer across the monolayer. In contrast, the condensed monolayer significantly diminished the rates of ion transfer for both TMA+ and ClO4− ions, suggesting that the presence of the condensed monolayer altered the rate-determining step and that the condensed monolayer exerted an additional hydrodynamic friction on the ion-transfer processes.
Substituent Effects on the 1H, 13C, and 15N NMR Spectra of Substituted Benzanilides
Authors: Suezawa Hiroko , Yuzuri Tomoaki , Hirota Minoru , Ito Yoshio , Hamada Yoshiki 
Published: July 2006

Abstract
The 15N, carbonyl 13C, and amide 1H NMR spectra of a series of substituted benzanilides, XC6H4CONHC6H4Y, measured in four solvents of different polarity were correlated with the electronic effects of substituents by the use of the Hammett equation. Except for the 13C chemical shift vs. the σx plot, the ρ-values are positive, showing that the chemical shift tends to move down-field as the substituent becomes electron-withdrawing. Substituent effects could be assumed to arise from a cross conjugation of competing amide and benzoyl resonance structures perturbed via an inductive mechanism by the substituent on the anilino ring. The 15N chemical shifts of XC6H4CONHC6H5 can be expected to be correlated with the rotational barrier, since the down-field shift of the 15N chemical shift (in reference to unsubstituted) benzanilide was ascribed to a steric inhibition of the aryl-carbonyl conjugation. This trend is actually shown by a plot of the 15N chemical shift vs. the rotational barrier of a similarly substituted N,N-dimethylbenzamide. The NH group of 2-methoxy- and 2-chlorobenzanilides was shown to be intramolecularly hydrogen bonded with the ortho substituent (CH3O or Cl) by their 1H NMR and infrared NH spectra.
Structures of Hydrated Titanium and Vanadium Ions in Aqueous Solutions Studied by X-Ray Absorption Spectroscopy
Authors: Miyanaga Takafumi , Watanabe Iwao , Ikeda Shigero 
Published: July 2006

Abstract
The structures of titanium(III) and (IV), as well as vanadium(II), (III), and (IV) ions in aqueous solutions were investigated by the use of EXAFS (Extended X-ray Absorption Fine Structure) and XANES (X-ray Absorption Near Edge Structure). The TiIV ion in a sulfuric acid solution was found to form a–TiIV–O–TiIV–chain structure which is known to be present in the TiOSO4·2H2O crystal. The XANES spectrum of a mixed-valence complex, TiIII–IV, in solution agrees with the sum of the individual XANES spectra of TiIII and TIIV, indicating a retention of individual oxidation states and coordination structures. While the peaks pertaining to Ti–Ti and V–V interactions were observed in the EXAFS Fourier transform spectra for TiIV in a sulfuric acid solution and for VIII in a hydrochloric acid solution, the mixed-valence complex, TiIII–IV, did not show the T1–Ti peak.
Photoelectrochemical Properties of Thin Films of Cadmium, Zinc, and Magnesium Porphyrins with Pyridyl Group
Authors: Takahashi Kohshin , Katsurada Hisashi , Komura Teruhisa , Imanaga Hiroto 
Published: July 2006

Abstract
Cadmium and zinc porphyrins with pyridyl or aminophenyl group gave smaller activation energy for the transfer of the carriers photoproduced in the solid thin film and larger cathodic photocurrent in quinhydrone solution than tetraphenylporphyrinato-cadmium and -zinc. The properties may be ascribed to the molecular arrangement of the porphyrins in the film.
2,6-Bis[N-(8-quinolyl)carbamoyl]pyridine as a Highly Selective Extractant for Cu(II)
Authors: Hiratani Kazuhisa , Taguchi Kazuhiro 
Published: July 2006

Abstract
Pyridine derivatives containing two 8-quinolyl-amino groups were newly synthesized for heavy metal ion-cheletion. It was shown in solvent extraction that 2, 6-bis[N,N′-(8-quinolyl)aminocarbonyl]pyridine can extract only Cu(II) with excellent selectivity and efficiency from the aqueous phase(pH 6.2) containing Cu(II), Ni(II), Co(II), and Zn(II) into the chloroform phase.
Photochemical Properties of TiO2 Microcrystallites Prepared in Nafion
Authors: Miyoshi Hirokazu , Nippa Satoru , Uchida Hiroyuki , Mori Hirotaro , Yoneyama Hiroshi 
Published: July 2006

Abstract
TiO2 microcrystallites of different sizes were prepared in Nafion and the energy diagrams of these were determined from the onset potential of photocurrents due to oxidation of tartrate ions and the bandgap energy which was estimated from absorption spectra. The smallest particle prepared in the present study had the diameter less than 2 nm and the bandgap energy of 3.95 eV. Photocatalytic activities of the TiO2 microcrystallites prepared in Nafion for photodecomposition of acetic acid were very low compared to those of TiO2 microcrystallites prepared in clay interlayers and were comparable to those of the latter photocatalysts obtained in the presence of SO42−, suggesting that sulfonate groups of Nafion made the photocatalytic activity of TiO2 microcrystallites decrease.
EPR Investigation of the Binuclear Copper(II) Complexes with 3,12-Bis(carboxymethyl)-6,9-dioxa-3,12-diazatetradecanedioic Acid
Authors: Kawata Satoshi , Yokoi Hiroshi , Iwaizumi Masamoto 
Published: July 2006

Abstract
Binuclear copper(II) complexes of 3,12-bis(carboxymethyl)-6,9-dioxa-3,12-diazatetradecanedioic acid have been investigated by EPR. It has been confirmed that three different binuclear complexes are formed, depending on the pH of the solution. The complex formed in the low pH region has a copper–copper distance of 5.5 Å and a weak magnetic dipolar interaction. The other two are of olated forms with strong magnetic interactions between the copper atoms through oxygen bridges. One of them has an antiferromagnetic interaction; though the other has a weak antiferromagnetic interaction, it shows a large zero-field splitting. Such differences between the magnetic properties of the two olated complexes are attributed to a difference in the bridged style, i.e., the former is a mono-μ-hydroxo-bridged complex and the latter is a double-μ-hydroxobridged complex.
An X-ray Diffraction Study on Zinc(II) Complexes with α-Alaninate Ion in Aqueous Solution
Authors: Radnai Tamas , Inoue Kenta , Ohtaki Hitoshi 
Published: July 2006

Abstract
The structures of mono(α-alaninato)zinc(Il), bis(α-alaninato)zinc(II), and tris(α-alaninato)zincate(II) complexes in aqueous solutions were determined by the X-ray diffraction method. All the three complexes have the octahedral structure in the form [Zn(α-ala)(H2O)4]+, [Zn(α-ala)2(H2O)2], and [Zn(α-ala)3]−. The structures of the complexes were different from those of the glycinato complexes of zinc(II) ion, which were all regular octahedral. The length of the Zn–O bond in the α-alaninato complexes was shorter than that of the Zn–N bond due to the inductive effect of the substituted methyl group at the α-carbon on the oxygen atom in the amino acid. The lengths of the Zn–O and Zn–N bonds in the complexes determined are, respectively, as follows: [Zn(α-ala)(H2O)4]+, 202 and 214 pm; [Zn(α-ala)2(H2O)2], 203 and 214 pm; [Zn(α-ala)3]−, 202 and 213 pm.
Synthesis and Characterization of Palladium(II) and Platinum(II) Complexes Containing Monodentate Phosphorus Donating or Chelating 2-(Dimethylphosphino)pyridine (PMe2py)
Authors: Suzuki Takayoshi , Kita Masakazu , Kashiwabara Kazuo , Fujita Junnosuke 
Published: July 2006

Abstract
The complexes [MX2(PMe2py-P)2] (M=Pd(II), Pt(II); X=Cl, Br, and I) have been synthesized and characterized both in the solid state and in solution by their infrared and 1H, 13C, and 31P NMR spectra, in addition to an X-ray crystallographic analysis of cis-[PdCl2(PMe2py-P)2]. The latter complex exists as a cis–trans equilibrium mixture in solution, while only the cis isomer has been isolated in the solid state. The [PdBr2(PMe2py-P)2] complex which has been isolated as the trans isomer shows also the same isomerization in solution, in contrast to [PdBr2(PMe2Ph)2] which exists only as the trans isomer both in the solid state and in solution. Furthermore, PMe2py has been found to have the ability for chelation via the nitrogen and phosphorus atoms to make a four-membered chelate ring. The chelate ring in the complexes [PdX(PMe2py)2]Y (X=Cl, Br, and I; Y=ClO4−, PF6−) has been confirmed by infrared spectra and X-ray analysis of cis(P,P)-[PdCl(PMe2py-P,N)(PMe2py-P)]ClO4. This is the first example in which PMe2py is acting as a chelating ligand.
Preparation of 14-, 18-, and 22-Membered Tetraaza Macrocycles and Their Complexing Ability for Copper(II) and Nickel(II) Ions
Authors: Fujiwara Manabu , Wakita Hisanobu , Matsushita Takayuki , Shono Toshiyuki 
Published: July 2006

Abstract
14-,18-, and 22-membered tetraaza macrocycles have been prepared by the reaction of acetylacetone with ethylenediamine, 1,4-butanediamine, or 1,6-hexanediamine, respectively. Their copper(II) and nickel(II) complexes were characterized by electronic and infrared spectroscopies. The 14-membered macrocycle forms a mononuclear copper(II) complex with a planar structure, whereas the 18-membered macrocycle forms a mononuclear copper(II) complex with a pseudo-tetrahedral structure, and the 22-membered macrocycle forms di- and trinuclear copper(II) complexes. The complexation and extraction abilities of these macrocycles toward copper(II) and nickel(II) ions are discussed.
Synthesis and Properties of a Heterodetic Cyclic Peptide: Gramicidin S Analog Containing Disulfide Bond
Authors: Satoh Ken-ichi , Okuda Hirofumi , Horimoto Hideaki , Kodama Hiroaki , Kondo Michio 
Published: July 2006

Abstract
In order to investigate the relationship between the structure of a peptide backbone and the formation of an intramolecular disulfide bond (S–S) in the peptide, a linear analog (1) of gramicidin S and a heterodetic cyclic peptide containing an S–S bond (2) were synthesized by the conventional solution method. Since a disulfide bonded compound (2) was easily formed by a treatment of the acetamidomethyl(Acm)-protected linear peptide (1) with iodine in good yield (70%), it is suggested that the mutual position between Cys1 and Cys8 residues becomes approximate, owing to the contribution of –d-Phe–Pro– part of the sequence. A heterodetic cyclic peptide (2) showed about 1/16–1/8 fold activity compared to that of GS; 1 as inactive. By the construction of an S–S bridge on the peptide backbone (1), an inactive peptide derivative was effectively converted to an active analog (2). The CD spectrum pattern also suggests that the heterodetic cyclic peptide (2) has a GS-like structure.
Stereoselectivity in the Oxidation of 5-Thioglucose Derivatives with 3-Chloroperoxybenzoic Acid
Authors: Yuasa Hideya , Takenaka Akio , Hashimoto Hironobu 
Published: July 2006

Abstract
5-Thio-α-d-glucopyranose derivatives were oxidized with 3-chloroperoxybenzoic acid in various conditions to give axial and equatorial sulfoxides. Structure of an axial sulfoxide obtained was determined by X-ray crystallography. Configuration of other sulfoxides was determined by 1HNMR spectroscopy according to empirical rules of chemical shift. The anomeric substituent was decisive for the stereoselectivity and the ratios of axial to equatorial sulfoxide were 3–11.5 for methoxy derivatives and 0.4–1.0 for acetoxy derivatives.
“pKa” of Calixarenes and Analogs in Nonaqueous Solvents
Authors: Araki Koji , Iwamoto Koji , Shinkai Seiji , Matsuda Tsutomu 
Published: July 2006

Abstract
The acid dissociation constants (Kapp) of p-t-butylcalix[n]arenes (1n: n=4, 6, and 8), O-methylated p-t-butylcalix[4]arene (2Men), and their noncyclic analogs (3n) were estimated in THF at 25°C. As pH indicators, Et4N+ salts of p-nitrophenolate, 2,4-dinitrophenolate, and picrate were employed. The pKapp values for 1n were lowered by at least four pK units from that of p-t-butylphenol because of strong intramolecular hydrogen-bonding interactions. Compounds 2n involved both the strong and weak hydrogen bonds: the proton in the strong hydrogen bond showed the acidity comparable with that of 1n whereas that in the weak hydrogen bond showed the relatively high pKapp. These properties were discussed in relation to δOH (chemical shift in 1HNMR) and νOH(OH vibration band in IR). This is the first systematic discussion on “pKa” of p-t-butylcalix[n]arenes.