bluuebunny/crossref_metadata_2025_split huggingface dataset:
Kinetics and Mechanism of the Substitution of β-Diketonates for Acetylacetonate in Bis(acetylacetonato)(trimethyl phosphate)dioxouranium(VI)
Authors: Udagawa Yoshiko , Tomiyasu Hiroshi , Jung Woo-Sik , Eom Tae Yoon , Fukutomi Hiroshi 
Published: July 2006

Abstract
Kinetics of the substitution of β-diketonates for one acetylacetonate in UO2(acac)2tmp (acac=acetylacetonate, tmp=trimethyl phosphate) has been studied in tmp by spectrophotometric methods. The reactions proceed through intermediate complexes UO2(acac)2HB, where HB denotes various β-diketones. The formation of the intermediates are followed by intramolecular proton transfer processes from coordinated HB to one of two acac in UO2(acac)2HB. The proton-transfer step for various HB can be classified into two groups owing to the difference in the values of rate constants k2, i.e. the substitutions of Hbza, Hhpd, and Hdbm and those of Hbta, Htta, and Htfa, k2 of the former group giving the order of 10−3 s−1, while that of the latter the order of 10−1 s−1, at 25 °C, where Hbza=benzoylacetone, Hhpd=3,5-heptanedione, Hdbm=dibezoylmethane, Hbta=benzoyltrifluoroacetone, Htta=2-thenoyltrifluoroacetone, and Htfa=trifluoroacetylacetone. This can be well explained in view of the acidity of β-diketones. The addition of amphiprotic solvents, such as water and alcohols, accelerates the substitution rates, and the observed first-order rate constant kobsd is expressed by kobsd=k2+kc[solvent]. In the case of the addition of alcohols, kc increases in the order: n-BuOH&lt;i-PrOH&lt;n-PrOH&lt;EtOH&lt;MeOH. This is the reverse order of autoprotolysis constants of these alcohols. Kinetic isotope effects kcH/kcD for the substitution of Hbza in tmp in the presence of H2O (or D2O) and CH3OH (or CH3OD) were determined to be 2.5 and 1.8, respectively.
Behaviors of the Enthalpies of Mixing and Formation in the System Lead–Indium
Authors: Badawi Walid Ahmad 
Published: July 2006

Abstract
The paper presents results of calorimetric studies on the enthalpies of mixing and formation in the system lead–indium. The enthalpy of formation is negative and becomes more negative at higher composition. The partial enthalpy of formation of lead is negative but increases at higher composition. The partial enthalpy of formation of indium is also negative and decreases with increasing the composition. The enthalpy of formation displays a considerable temperature dependence which seems to be smaller than that observed for the enthalpy of formation in other systems.
Studies of Collectors. XI. The Preparation of Cyclic Polyamine-Type Surfactants and Application to Ion-Flotation Collectors
Authors: Yamada Kimiho , Koide Yoshifumi , Yamanokuchi Hiroshi , Ohmura Masaki , Shosenji Hideto 
Published: July 2006

Abstract
Inclusion-type surfactants bearing cyclic dioxopolyamine (RndoN4, RndoN5) or cyclic polyamine (R12N4, 2.4R-N6, Ls6.8N6) were prepared and then investigated as ion-flotation collectors. The surface tensions of the surfactant solutions were 30–40 dyn cm−1. The molecular areas of the surfactants in the aqueous solutions, as calculated from the Gibbs adsorption isotherm, were discussed in connection with the structures of the RndoN4 and its Cu2+ complex. Heavy metal ions were floated with RndoN4 or RndoN5. The highest floatabilities of Cu2+ and Ni2+ were in the pH range of 10–12, while that of Fe3+ was in the pH range of 6–10. Furthermore, similar characteristics of the metal floatabilities were obtained by using R12N4 and alkylated linear polyamine. The flotation using RndoN4 or RndoN5 was done by the complex formation, but that using R12N4 or 2.4R-N6 was done by the neutralization of the complex with OH−. The selectivities in pH 4–8 were Cu2+&gt;Ni2+&gt;Fe3+&gt;Zn2+ when RndoN4 was used and Fe3+&gt;Cu2+&gt;Ni2+&gt;Zn2+ when RndoN5 was used.
Effects of Polysubstitution on Mesomorphic Properties: Chloro and Methyl Derivatives of N-[4-(4-Substituted benzoyloxy)benzylidene]anilines
Authors: Hasegawa Hiroyuki , Masuda Tatsuya , Matsunaga Yoshio , Seo Sachiko , Yasuhara Kazuaki 
Published: July 2006

Abstract
The effects of mono-, di-, and trichloro substitution of the aniline moiety on the nematic-isotropic transition temperature of N-[4-(4-X-substituted benzoyloxy)benzylidene]anilines, where X=CH3O, CH3, or Cl, have been studied, while paying particular attention to the vicinal chlorines. While the substituent on the 2 or 3 position of the aniline moiety lowers the transition temperature of the parent compound and the 4-chloro derivative, the 2,3-dichloro derivative shows a temperature higher than that of either the 2- or 3-chloro derivative. Moreover, the transition temperature of the 2,3,4-trichloro derivative exceeds that of the 3,4-dichloro derivative and is a little below that of the 2,4-dichloro isomer. In contrast, the introduction of 4-substituent increases the temperature, regardless of the position(s) of the other substituent(s). Methyl substitution exerts effects closely similar to those described above.
A Simple and Rugged Home-Built Scanning Tunneling Microscope for Operation in Both Air and Liquid
Authors: Sakamaki Kenji , Itoh Kiminori , Fujishima Akira , Gohshi Yohichi , Nakagawa Hidemoto 
Published: July 2006

Abstract
A simple, rugged home-built scanning tunneling microscope for operation in both air and liquid that uses a Z-stage micrometer to provide coarse mechanical positioning is described. The construction of this STM was accomplished at low cost without precision machining. The tunneling current is typically acquired within 10–15 minutes. The atomic resolving power of our STM has been demonstrated by a cleaved HOPG at a 15-Hz scanning rate in air. There was no use of plate-stack-type isolators, due to the high rigidness of the tunneling unit. The STM image of a HOPG in ultrapure water was also observed with a glass-coated tip. Images of a pc-Ag electrode in 0.1 mol dm−3 KCl demonstrate stable operation in a liquid solution. The lateral drift was shown to be less than 0.13 nm min−1 for operation in liquid, estimated by subsequent imaging of the same area. This STM is easy to handle and has a suitable design for in situ electrode surface characterization.
Optical and Magnetic Resonance Studies of the Interaction of Metallotetraphenylchlorin and Octaethylporphyrin with Trinitrofluorenone
Authors: Choudhury Biswajit , Chandrashekar T K 
Published: July 2006

Abstract
The interaction of metallo derivatives of tetraphenylchlorin (TPC) and octaethylporphyrin (OEP) with 2,4,7-trinitrofluorenone (TNF) is described in terms of 1 : 1 molecular complexes. The binding constants vary as CuOEP&gt;ZnOEP&gt;CuTPC&gt;ZnTPC and this variation is accounted in terms of the structure of the macrocycle and the substituents presen on it. ESR studies of the complexes reveal that the π-complexation results in changes in the electronic structure of the central metal ion. The magnitude of different proton shifts of the acceptor in 1H NMR spectra of the complexes are used to arrive at the possible solution structure of the complexes.
Generation of Enolates from α,β-Epoxy Sulfoxides with Lithium Dimethylcuprate: A Novel Synthesis of Aldols and Some Trial to Trap the Enolates
Authors: Satoh Tsuyoshi , Sugimoto Atsushi , Itoh Masayuki , Yamakawa Koji 
Published: July 2006

Abstract
Enolates were generated from α,β-epoxy sulfoxides using lithium dimethylcuprate as an electron-transfer reagent. The enolates were trapped with several electrophiles, in which aldehydes reacted with the generated enolates giving aldols in good yields with high regioselectivity.
2A,2B-, 2A,2C-, and 2A,2D-Bis-O-(p-tolylsulfonyl)-β-cyclodextrins
Authors: Fujita Kahee , Ishizu Takashi , Oshiro Kyoko , Obe Ken-ichi 
Published: July 2006

Abstract
A mixture of the title ditosylates was prepared by the reaction of β-cyclodextrin with dibutyltin oxide and tosyl chloride. Each ditosylate was isolated by reversed-phase column chromatography and the structure was assigned on the basis of conversion into a known compound or hydrolysis with Taka amylase A.
(−)-(9Z)-1,9-Heptadecadiene-4,6-diyn-3-ol as a Principal Component of the Resinous Sap of Evodiopanax innovans Nakai, Japanese Name, Takanotsume, and Its Role in an Ancient Golden Varnish of Japan
Authors: Terada Akira , Tanoue Yasuhiro , Kishimoto Daishiro 
Published: July 2006

Abstract
(−)-(9Z)-1,9-Heptadecadiene-4,6-diyn-3-ol was for the first time isolated in high yield (29%) from the resinous sap of Evodiopanax innovans Nakai, Araliaceae. This compound has been associated with the main polymerizable component of an ancient golden varnish. It has also been associated with a phytoalexin and a defense material which produces a water-insoluble coating film by photopolymerization under sunlight for a Takanotsume tree upon being wounded.
Molecular Aggregation Structure of Barium Stearate Monolayer Based on Electron Microscopy
Authors: Kajiyama Tisato , Umemura Kazuo , Uchida Motoko , Oishi Yushi , Takei Ryutaro 
Published: July 2006

Abstract
Aggregation structure of barium stearate monolayers prepared from a benzene solution at various surface pressures was investigated by using a transmission electron microscope. Two-dimensional crystallites of the monolayer were formed even at the surface pressure of 0 mN · m−1. The monolayer crystallites on the water surface became a continuous phase at 25 mN · m−1 and collapsed at 40 mN · m−1. The surface pressure–area isotherm represents an aggregating process of the small two-dimensional crystallites on the water surface, instead of a generally accepted concept on phase transitions among gas, liquid, and solid phases.
An Exceptionally-Large Negative Halochromism in 2-(4-Ethoxycarbonylphenyl)2,3-dihydro-3,3-dimethyl-5,6-cycloheptapyrazoledione, a Hinopurpurin Derivative
Authors: Mori Akira , Li Zhi-Hong , Takeshita Hitoshi 
Published: July 2006

Abstract
2-Aryl-2,3-dihydro-3,3-dimethyl-5,6-cycloheptapyrazolediones with an electron-releasing group at C-4 on the benzene ring showed a bathochromic shift in acid solution, whereas the 4-ethoxycarbonylphenyl derivative showed a negative halochromism; 484 nm in ethyl acetate, 517, 566, and 600(sh) nm in trifluoroacetic acid, and 455 nm in coned sulfuric acid.
New Approaches to Tetracyanoquinodimethane
Authors: Yamaguchi Shunro , Miyamoto Kazuyuki , Hanafusa Terukiyo 
Published: July 2006

Abstract
New synthetic methods of tetracyanoquinodimethane from terephthaloyl dichloride were presented. Conversion of terephthaloyl dichloride to 1,4-bis(dicyanobenzoyloxymethyl)benzene, followed by debenzoyloxylation and succeessive oxidation afforded TCNQ.
High-Resolution Solid-State 31P NMR of Alkali Phosphates
Authors: Hayashi Shigenobu , Hayamizu Kikuko 
Published: July 2006

Abstract
High-resolution solid-state 31P NMR spectra have been measured for inorganic alkali phosphates with different condensations in the PO4 units, and the isotropic chemical shift and anisotropy have been determined. The isotropic chemical shifts in alkali orthophosphates do not correlate directly with the cation size. The hydration effects have been carefully examined by means of a 1H decoupling experiment and by the heat treatment of the materials, accompanied by thermogravimetric analysis. Hydration causes an upfield shift in Na3PO4, K3PO4, and Na4P2O7, while it causes a downfield shift in Rb3PO4 and Cs3PO4. All the five peaks observed in the K4P2O7 sample can be ascribed to anhydrous species; this is in contrast to the findings of previous works. The field-dependence experiments definitely demonstrate that the splittings in K4P2O7 and (KPO3)n are caused by inequivalent sites.
Fluorescence Studies on the Phase Dependence of Interactions between a Tripeptide, Lys–Trp–Lys, and Dimyristoylphosphatidylserine
Authors: Yamashita Shoji , Szabo Arthur G , Krajcarski Donald T , Yamasaki Nobuyuki 
Published: July 2006

Abstract
Interactions of a basic tripeptide, lysyl-tryptophyl-lysine (LTL) with dimyristoylphosphatidylserine (DMPS) were investigated by fluorescence spectroscopy. An interacting LTL–DMPS complex assumes two distinctly different conformations in the lipid bilayer depending on the thermotropic phase of lipid. At temperatures below the gel–liquid crystalline phase-transition temperature (Tc), LTL binds to the polar head groups of DMPS through electrostatic force, and the tryptophan residue is located on the surface of the membrane because of the rigidity of the head groups. Above Tc, it assumes a conformation such that the tryptophan residue slips deeply into the DMPS bilayer. The temperature dependence of the fluorescence quenching by acrylamide supported the penetration of the tryptophan upon the phase transition of DMPS. A fluorescence decay analysis based on the photophysical deactivation mechanism of tryptophan residue has revealed a peculiar interaction of LTL with DMPS in the bilayer.
Response and Application in Dipolar Aprotic Solvents of Ion-Selective Electrodes Based on Polyacrylamide Modified with Acyclic Poly(oxyethylene) Derivatives
Authors: Nakamura Toshio , Higuchi Hisakazu , Izutsu Kosuke 
Published: July 2006

Abstract
The response of organic polymer membrane electrodes, constructed by coating a platinum disk with polyacrylamide (PAA) coupled to acyclic poly(oxyethylene) derivatives, tetraethylene glycol monododecyl ether (POE4) and hexaethylene glycol monododecyl ether (POE6) was studied in acetonitrile (AN) and N,N-dimethylformamide (DMF). The PAA–POE4 electrode showed Nernstian response to the lithium ion in AN and the magnesium and barium ions in DMF, while the PAA–POE6 electrode showed near Nernstian response to the barium ion in DMF. The PAA–POE4 electrode was applied to study the complexation of the lithium ion in AN with DMF. The formation constants, β1=17 and β2=1.2×102, obtained agreed well with the values obtained previously with an univalent cation sensitive glass electrode. The response of the PAA-POE4 electrode in barium bis(2-ethylhexyl) sulfosuccinate (Ba(DSS)2)–DMF solution has been studied and the results are explained by taking the conductometrically determined association constant (K1A=5.2×102) between Ba2+ and DSS− ions.
Peptide Synthesis in Aqueous Solution. IV. Preparation and Properties of [p-(Benzyloxycarbonyloxy)phenyl]dimethylsulfonium Methyl Sulfate (Z-ODSP), [p-(t-Butoxycarbonyloxy)phenyl]dimethylsulfonium Methyl Sulfate (Boc-ODSP) and [p-(9-Fluorenylmethyloxycarbonyloxy)phenyl]dimethylsulfonium Methyl Sulfate (Fmoc-ODSP) as Water-Soluble N-Acylating Reagents
Authors: Azuse Ikunori , Tamura Masahiro , Kinomura Keisuke , Okai Hideo , Kouge Katsushige , Hamatsu Fumio , Koizumi Tatsuya 
Published: July 2006

Abstract
In order to increase the applications of the water-soluble active ester method, water-soluble acylating reagents, [p-(benzyloxycarbonyloxy)phenyl]dimethylsulfonium methyl sulfate, [p-(t-butoxycarbonyloxy)phenyl]dimethylsulfonium methyl sulfate and [p-(9-fluorenylmethyloxycarbonyloxy)phenyl]dimethylsulfonium methyl sulfate, were synthesized from of p-hydroxyphenyldimethylsulfonium methyl sulfate. These compounds had high solubility (more than 30%) in water and were found to act as excellent water-soluble acylating reagents for the synthesis of N-benzyloxycarbonyl, N-t-butoxycarbonyl, N-9-fluorenylmethyloxycarbonyl amino acid derivatives in aqueous solution. They converted dipeptides to N-acyl-dipeptides in aqueous media as well as amino acids. In addition, they were found to be efficient reagents for protecting the side chains of lysine, ornithine, and cysteine.
Sulfur Nitrides in Organic Chemistry. 18. Preparation and Reduction of Benzo[1,2-c:3,4-c′:5,6-c″]tris- and Benzo[1,2-c:3,4-c′]bis[1,2,5]thiadiazole. A Convenient Route to Benzenehexamine and 1,2,3,4-Benzenetetramine
Authors: Mataka Shuntaro , Eguchi Hisao , Takahashi Kazufumi , Hatta Taizo , Tashiro Masashi 
Published: July 2006

Abstract
Benzotris- (3) and benzobis[1,2,5]thiadiazole (4) were prepared in a moderate yield, respectively, by the reaction of tetrasulfur tetranitride (5) with halocatechols (6) and -resorcinols (7). The reduction of 3 and 4 with Sn powder in a mixture of concentrated hydrochloric acid and dioxane gave benzenehexamine (1) and 1,2,3,4-benzenetetramine (2a) and its 5-methyl derivative (2b) in good yields, as a stable tri- (1·3HCl) and dihydrochloride (2·2HCl), respectively.
Enzymatic Synthesis of Specifically Modified Linear Oligosaccharides from γ-Cyclodextrin Derivatives. Study on Importance of Active Sites of Taka Amylase A
Authors: Fujita Kahee , Tahara Tsutomu , Koga Toshitaka , Imoto Taiji 
Published: July 2006

Abstract
Specifically modified linear oligosaccharides were prepared by enzymatic hydrolysis of 6- or 2-O-substituted γ-cyclodextrin by Taka amylase A. These results suggest that the importance of the interactions between hydroxyl groups and the subsites (P–V) of Taka amylase A decreases in the following order; for C-6-OH, S&gt;R&gt;T&gt;Q, U and for C-2-OH, R,S&gt;T&gt;Q, U.
Unusual Reactivity of Purinophanes Due to Stereoelectronic Effect
Authors: Sakata Yoshiteru , Higuchi Hiroyuki , Doyama Kazuo , Higashii Takayuki , Mitsuoka Miho , Misumi Soichi 
Published: July 2006

Abstract
Four types of purinophanes (1, 2, 7, and 10) where a 6-thiopurine ring is bridged between S6- and 9-positions or between S6- and 7-positions were synthesized. Among them (6,9)purinophanes (1, 7, and 10) showed unusual high reactivity toward nucleophiles (MeNH2, Me2NH, OH−) at 6-position to give acyclic compounds. The increased rate constants of these compounds against (6,7)purinophanes 2 and 9-methyl-6-(methylthio)purine could not be explained by molecular strain, neighboring group participation, or some electronic effect due to faced π-systems, but successfully explained by the stereoelectronic effect proposed by Deslongchamps. The rate of the reactions in 1, 7, and 10 was increased with an increase in rigidity of the tetrahedral intermediate where lone pairs of two adjacent heteroatoms orient antiperiplanar to the departing group.
The Effect of Alternative Magnetic Field on the Pigment Ejection from Magnetic Anisotropic Gel Beads
Authors: Sakai Yasuzo , Taguchi Hidefumi , Takahashi Fujio 
Published: July 2006

Abstract
Magnetic anisotropic gel beads (MA gel beads) were prepared by the gelation of a ferrite suspension in a static magnetic field. MA gel beads were found to oscillate in an alternating magnetic field. This oscillation can possibly reduce the thickness of the diffusion layer on the interface between the gel beads and the surrounding solution, so that the substance can be transferred more quickly across the gel–liquid interface. MA gel beads consisted of alginate gel containing ferrite powder and toluidine blue as a pigment. MA gel beads were loaded into a dual glass tube to make a column bed, which was inserted into a coreless coil which produced the alternating magnetic field. The concentration change of the pigment in the effluent from the column was measured during a lapse in time with repeating off and on the input of the alternating magnetic field. The pigment concentration in the effluent upon exposure to the alternating magnetic field increased to twice the maximum value obtained without a magnetic field. The stronger was the static magnetic field at the time of gelation and the alternating magnetic field, the larger was the increase in pigment concentration in the effluent. Also, the higher was the concentration of ferrite in gel beads, the larger was the increase in pigment concentration in the effluent.
Synthesis and Spectral Analysis of Some Schiff Bases Containing Long Alkyl Chains
Authors: Senapati Sushree , Mishra Bijaya Kumar , Behera Gopa Bandhu , Mahendroo Prem Prakash 
Published: July 2006

Abstract
Schiff bases containing hydrophobic alkyl chains have been synthesized and the IR, 1H NMR, 13C NMR, and mass spectral data of some of the compounds have been reported.
Syntheses, Spectroscopic Properties, Crystal Structures, and Antitumor Activities of the Optically Isomeric Mandelate Chelates, Mandelato(trans-1,2-diaminocyclohexane)platinum(II)
Authors: Miyamoto T Ken , Okude Kojiro , Maeda Kazuyuki , Ichida Hikaru , Sasaki Yukiyoshi , Tashiro Tazuko 
Published: July 2006

Abstract
The four optical isomers of mandelato(trans-1,2,-diaminocyclohexane)platinum(II) have been prepared. The CD and NMR spectra of these compounds in solution indicate that the mandelate coordinates to platinum(II) to form a five-membered chelate ring. The X-ray crystal structure analyses of a pair of diastereomers, (R)-mandelato[(1R,2R)-1,2-diaminocyclohexane]platinum(II) and (S)-mandelato[(1R,2R)-1,2-diaminocyclohexane]platinum(II), have confirmed that the skeletal configuration of (R)- or (S)-mandelic acid is retained during the chelation of platinum(II). As a whole, the structural features of both diastereoisomers are analogous to each other. However, slight differences in hydrogen bonding are noticeable in relation to the solubilities. A preliminary animal test against mice leukemia L1210 was carried out using these compounds. The four isomers show different activities. All these facts together support the conclusion that the chiralities of both ammine (carrier) and mandelate (leaving group) influence the antitumor activities of the platinum agents.
Studies on Tetramethyldithizone Isomers and Their Reactions with Metal Ions
Authors: Kiwan A M , Hassan F M , Hamdan W 
Published: July 2006

Abstract
Six bis(dimethylphenyl) analogues of dithizone are prepared, characterized and their reactions with metal ions in a two phase system are reported. The extraction equilibria of their complexes with Cd(II), Co(II), Hg(II), Pb(II), Tl(I), Zn(II), and Bi(III) as well as their spectral characteristics are described. Complete extraction of these metal chelates requires higher pH’s than those needed for the unsubstituted dithizone. The molar absorptivities of Bi(III) complexes with bis(3,4-dimethylphenyl)-, and bis(3,5-dimethylphenyl) analogues are higher than the corresponding value of Bi(III) dithizonate. The molar absorptivities of Cu(II) and Hg(II) (in CCl4) complexes with bis(3,5-dimethylphenyl) analogue are also higher than the corresponding values of the unsubstituted dithizone complexes.
125Te and 129I Mössbauer Spectroscopic Studies of the Tetragonal and Orthorhombic Forms of Tellurium(IV) Oxide
Authors: Sakai Hiroshi , Maeda Yutaka 
Published: July 2006

Abstract
125Te and 129I Mössbauer spectra have been measured for the tetragonal (α) and orthorhombic (β) forms of TeO2. The Mössbauer data show that there are no significant differences between the two modifications in either the electronic structure or the chemical bonding of the tellurium atoms; this is consistent with the crystallographic data. From a comparison of the Mössbauer data for 125Te with those for 129I, we have concluded that the 129I daughter nucleus, produced by the nuclear β− decay of 129Te, is present in the same lattice environment as the parent 129Te nucleus in TeO2. A Cu125I crystalline compound has been used as the Möossbauer source of 125Te, which emits a single line of resonance γ-ray. The values of the isomer shift and line width for the source are found to be −0.13 mm s−1 relative to the ZnTe standard absorber and 6.53 mm s−1 respectively.