bluuebunny/crossref_metadata_2025 huggingface dataset:
Age or Factors Associated with Aging Attenuate Testosterone’s Concentration-Dependent Enhancement of the Regularity of Luteinizing Hormone Secretion in Healthy Men
Authors: Liu Peter Y. , Takahashi Paul Y. , Roebuck Pamela D. , Veldhuis Johannes D.
Published: July 2006

Background: Healthy older men have reduced testosterone (Te) production and frequent, small irregular LH pulses. Which is cause and which is effect are not known.

Rationale: In model systems, frequent and irregular LH pulses reflect attenuated feedback inhibition by Te.

Hypothesis: Factors associated with aging impair negative feedback by Te.

Subjects and Setting: Healthy men at an academic medical center were studied.

Methods: The study used quantification of the regularity of LH release patterns during blockade of gonadal steroidogenesis and graded transdermal Te addback in 18 healthy men aged 18–65 yr.

Results: In the cohort as a whole, stepwise Te repletion repressed LH concentrations (P = 0.001) and enhanced the quantifiable orderliness of LH release patterns (P < 0.001). By regression analysis, age attenuated the capability of increasing Te concentrations to regularize LH secretion patterns (P = 0.019). However, after a fixed GnRH stimulus, the effect of Te on LH regularity was invariant of the age factor (P = 0.16), thus pointing to a hypothalamic locus of impaired Te feedback.

Summary: Aging disrupts the capability of systemic Te concentrations to maintain orderly LH secretion under endogenous, but not exogenous, GnRH drive.

Conclusions: Age or factors associated with increased age reduce negative feedback by any given total Te concentration on hypothalamopituitary GnRH-LH outflow, thus contributing to disorderly LH secretion.
A Novel Human Sex-Determining Gene Linked to Xp11.21-11.23
Authors: Rajender Singh , Thangaraj Kumarasamy , Gupta Nalini J. , Leelavathy N. , Rani Deepa Selvi , Nambiar Renjini G. , Kalavathy Vadivelu , Santhiya Sathiyavedu T. , Rajangam Sayee , Gopinath Puthiya M. , Chakravarty Baidyanath , Singh Lalji
Published: July 2006

Context: The molecular basis for about 70–80% of 46,XY sex-reversed females remains unexplained, because they carry normal copies of the genes (SRY, SOX9, DAX1, DMRT, SF1, WT1) involved in sex determination pathway.

Objective: The objective of this study is to map the chromosomal locus responsible for an unexplained sex-reversed phenotype.

Design: The study implemented a genome-wide scan using families with multiple sex-reversed individuals.

Setting: The patients, along with the family members, were selected from different hospitals/reproductive centers.

Participants: Sex-reversed individuals and their siblings and parents participated in the study.

Main Outcome Measures: Identification of the chromosomal locus responsible for sex reversal in these families and sequence analysis of candidate genes were the main outcome measures.

Results: Parametric linkage analysis revealed a maximum two-point LOD score of 5.70 with marker DXS991 (Xp11.21) and 4.57 with marker DXS1039 (Xp11.23-Xp11.22), and a multipoint LOD score of 5.77 with marker DXS991 and 5.22 with marker DXS1039. The two markers (DXS991 and DXS1039) with highest LOD score span approximately 3.41 cM (75.79–79.2 cM) on the short arm of the X-chromosome.

Conclusion: Our findings provide evidence for a major susceptibility locus for sex reversal/gonadal dysgenesis on the short arm of the X-chromosome (Xp11.21-11.23). Furthermore, molecular exploration of the expression of candidate genes in the embryonic gonad/gonadal ridge will help in the identification of the underlying gene for sex reversal.
Alleles ofafd1dissect REC8 functions during meiotic prophase I
Authors: Golubovskaya Inna N. , Hamant Olivier , Timofejeva Ljuda , Wang Chung-Ju Rachel , Braun David , Meeley Robert , Cande W. Zacheus
Published: July 2006

REC8 is a master regulator of chromatin structure and function during meiosis. Here, we dissected the functions of absence of first division (afd1), a maize rec8/α-kleisin homolog, using a unique afd1 allelic series. The first observable defect in afd1 mutants is the inability to make a leptotene chromosome. AFD1 protein is required for elongation of axial elements but not for their initial recruitment, thus showing that AFD1 acts downstream of ASY1/HOP1. AFD1 is associated with the axial and later the lateral elements of the synaptonemal complex. Rescuing 50% of axial element elongation in the weakest afd1 allele restored bouquet formation demonstrating that extent of telomere clustering depends on axial element elongation. However, rescuing bouquet formation was not sufficient for either proper RAD51 distribution or homologous pairing. It provides the basis for a model in which AFD1/REC8 controls homologous pairing through its role in axial element elongation and the subsequent distribution of the recombination machinery independent of bouquet formation.
Efficient ADAM22 surface expression is mediated by phosphorylation-dependent interaction with 14-3-3 protein family members
Authors: Gödde Nathan J. , D'Abaco Giovanna M. , Paradiso Lucy , Novak Ulrike
Published: July 2006

ADAM22 is one of three catalytically inactive ADAM family members highly expressed in the brain. ADAM22 has numerous splice variants, all with considerable cytoplasmic tails of up to 148 amino acids. ADAM22 can act to inhibit cell proliferation, however, it has been suggested that it also acts as an adhesion protein. We identified three 14-3-3 protein members by a yeast two-hybrid screen and show by co-immunoprecipitation that the cytoplasmic domain of ADAM22 can interact with all six 14-3-3 proteins expressed in the brain. In addition, we show that 14-3-3 proteins interact preferentially with the serine phosphorylated precursor form of ADAM22. ADAM22 has two 14-3-3 protein binding consensus motifs; the first binding site, spanning residues 831-834, was shown to be the most crucial for 14-3-3 binding to occur. The interaction between ADAM22 and 14-3-3 proteins is dependent on phosphorylation of ADAM22, but not of 14-3-3 proteins. ADAM22 point mutants lacking functional 14-3-3 protein binding motifs could no longer accumulate efficiently at the cell surface. Deletion of both 14-3-3 binding sites and newly identified ER retention motifs restored localization of ADAM22 at the cell surface. These results reveal a role for 14-3-3 proteins in targeting ADAM22 to the membrane by masking ER retention signals.
The X-Ray Study of Several Reaction Products of Substituted Benzo[1,2:4,5]dicyclobutene. II. 2,7-Di-t-butyl-11,12-dicyano-4,5,9,10-tetraphenyltetracyclo[4.4.2.01.8.03.6]dodeca-2,4,7,9-tetraene
Authors: Tsukada Harumichi , Shimanouchi Hirotaka , Sasada Yoshio
Published: July 2006

trans-1,2-Dicyanoethylene (DCNE) reacts with substituted benzo[1,2 : 4,5]dicyclobutene (1) to give only one adduct (4), the title compound, whereas tetracyanoethylene (TCNE) gives two isomers. Crystals of 4 are triclinic; space group P\bar1, a=13.505(2), b=14.118(2), c=10.722(1) Å, α=98.87(1), β=102.36(1), γ=111.71(1)° and Z=2. The structure was solved by the direct method and was refined by the block-diagonal least-squares method to the final R factor of 0.055 for 5479 observed reflections. The absence of two cyano groups in 4 makes less steric hindrance than 3. Introducing the empirical parameters, non-bonded interaction energy was calculated for the approaching model of 1 and DCNE. The result well explains the addition of DCNE to the C(1)–C(6) position of 1.
Effects of Salts on the Solubility of Elemental Mercury in Water
Authors: Sanemasa Isao , Haraguchi Kenji , Nagai Hideo
Published: July 2006

The effects of 11 salts, NaCl, NaNO3, Na2SO4, NaBr, NaSCN, NaF, NaClO4, KCl, BaCl2, (CH3)4NBr, and (C2H5)4NBr, on the solubility of elemental mercury in water have been studied at 25 °C. Salting coefficients were determined and compared with those predicted by both the McDevit-Long equation and the scaled particle theory (SPT). The McDevit-Long equation gave reasonably good predictions except for NaBr, NaClO4, and NaSCN. SPT is also applicable to prediction of the salt effect when the energy parameter of mercury determined from the Henry law constant of aqueous solubility of mercury vapor is employed. Attempts to predict the effects of tetraalkylammonium salts by SPT failed.
Study of the Mixed Ligand Complexes of Heavy Rare Earth Elements by Electromigration
Authors: Ohyoshi Emiko
Published: July 2006

The formation of the mixed ligand complexes of heavy rare earth elements with α-hydroxyisobutyric acid (AHIB or HA) and nitrilotriacetic acid (NTA or H3L) was studied by electromigration. The equations expressing the zone mobility as a function of the concentrations of the two ligands were derived with or without the mixed ligand complexes, MLA−. The experimental results showed that the MLA− complexes were formed. The formation constants for the Tb(III), Dy(III), Ho(III), Er(III), Tm(III), Yb(III), and Lu(III) complexes were determined. The results obtained by using the two series of solutions, with varying [L3−] at a constant [A−] and with varying [A−] at a constant [L3−], were in good agreement. The stability trend was in an ordinary decreasing sequence of: Lu>Yb>Tm>Er>Ho>Dy>Tb.
Models for Visual Pigments. The Effect of the Imidazolyl Group on the Absorption Maxima of the Retinal Schiff Base
Authors: Nanasawa Masato , Kamogawa Hiroyoshi
Published: July 2006

The title effect has been investigated with the imidazolyl group either externally added or intramolecularly combined. N-Retinylidenebutylamine was protonated with imidazole derivatives under neutral conditions and was absorbed at longer wavelengths compared with carboxylic acids. The absorption peak with the imidazolyl group intramolecularly combined was highly affected by the structure, protonated Nα-retinylidene-l-histidine octadecylamide having an absorption maximum at 494 nm caused by the inductive effect and the polar imidazolyl group.
The Application of Field-ionization and Field-desorption Mass Spectrometry to the Analysis of Coal-derived Oil
Authors: Yoshida Tadashi , Maekawa Yosuke , Higuchi Tetsuo , Kubota Eiji , Itagaki Yasuhiro , Yokoyama Susumu
Published: July 2006

Field-ionization (FI) and field-desorption (FD) mass-spectroscopic techniques have been applied to the analysis of ring-type fractions of coal-derived oil, obtained by liquid chromatography. These techniques produce only the molecular ion and its isotopic signals, free from fragment ions, of a molecule, consequently the exact molecularweight-distribution profiles of chromatographic fractions. The peak intensities are reproducible within a variation coefficient (σ/\barx) of about 5–8% on repeated runs. The number-average molecular weights (\barMn) of the ring-type fractions, as calculated from the peak intensities, are close to those obtained by means of a vapor-pressure osmometer (VPO). These techniques, on the whole, give reliable mass spectra of coal-derived oil, although the isotope-ion ratios are overestimated compared to the theoretical natural abundances. The group-type analysis of the ring-type fractions has been made on the basis of their mass spectra, and the skeletal structures corresponding to each mass z series have been proposed.
Structure of the Galacturonate and Glucuronate Complexes with Copper(II) in Aqueous Solution. A Calorimetric Study
Authors: Aruga Roberto
Published: July 2006

Heat and entropy of reaction of copper(II) with galacturonate and glucuronate anions have been determined by calorimetry. The measurements were performed in an aqueous medium at 25 °C and ionic strength I=1 M (NaNO3). The results indicate a bidentate action of the two ligands towards copper. The carboxylate group as well as the oxygen atom of the ring, the latter by means of an outer-sphere electrostatic bond, seem to interact with the cation.
Adsorption of Pyranine onto Cationic Liposomal Membranes as Evidenced by Fluorescence Polarizationt
Authors: Nomura Tadashi , Kondo Hiroki , Sunamoto Junzo
Published: July 2006

A trianionic fluorescent probe, pyranine, was found to bind to positively charged liposomes as evidenced by a linear increase in the fluorescence polarization with the liposome concentration. Addition of perchlorate ion reduced the polarization of fluorescence, suggesting that perchlorate and pyranine compete for the same binding site on the surface of cationic liposomal membranes.
1H NMR Study of Dissociation and Re-association of Apoferritin and Ferritin
Authors: Imai Noboru , Arata Yoji , Fujiwara Shizuo
Published: July 2006

The processes of dissociation and re-association of apoferritin and the protein part of ferritin were investigated by 1H NMR. It was suggested that the re-association of ferritin occurs more easily than that of apoferritin.
An Evaluation of Ion-exchange Membrane Electrodes
Authors: Hara Hirokazu , Okazaki Satoshi , Fujinaga Taitiro
Published: July 2006

The potentiometric response behavior and selectivity characteristics of ion-exchange membrane electrodes have been investigated. Nernstian responses were obtained for inorganic anions such as perchlorate, nitrate, and chloride with each form of Selemion ASV membrane. Highly selective exclusions of the divalent sulfate and large organic sulfonate anions were observed with those membranes.
Studies on the Chlorinated α-Santonins. III. Revised Structure of α-Santonin Chlorohydrin
Authors: Takayanagi Hiroaki , Ogura Haruo , Brian T , McMurry H
Published: July 2006

The molecular structure of α-santoninchlorohydrin is revised to 5β-chloro-4α-hydroxysantonin from 4α-chloro-5α-hydroxysantonin (Hendrickson and Bogard) by X-ray analysis of the corresponding 5β-chloro-4α-methoxysantonin.
Synthesis of 1,2,3,6,7,8-, 1,3,4,5,6,8-, and 1,2,3,5,6,8-Hexamethoxyxanthene
Authors: Obara Heitaro , Onodera Jun-ichi , Shibata Tsutomu , Shibayama Kimio
Published: July 2006

Three hexamethoxyxanthene isomers, 1,2,3,6,7,8-, 1,3,4,5,6,8-, and 1,2,3,5,6,8-hexamethoxyxanthene, were synthesized from the condensation products of 2,6-dimethoxyhydroquinone, 2,5-dimethoxyresorcinol, or 1,2,-3,5-benzenetetrol respectively with formaldehyde or ethyl formate.
Azadi-π-methane Rearrangement Involving an Oxime Group
Authors: Nitta Makoto , Kasahara Ichiro , Kobayashi Tomoshige
Published: July 2006

Photoreaction of exo-6-methoxy-1,5,6-trimethyl or exo-6-methoxy-1,3,5,6-tetramethyltricyclo[3.2.1.02,7]oct-3-en-8-one oxime underwent azadi-π-methane rearrangement leading to endo-7-methoxy-2,6,7-trimethyl or endo-7-methoxy-1,2,6,7-tetramethyltetracyclo[3.3.0.0.2,804,6]octan-3-one oxime. However, the one-carbon ring enlarged 5,8-dimethyl-9-methylenetricyclo[3.3.1.02,8]nona-3-en-6-one oxime underwent photo-Beckmann rearrangement to afford 5-aza2,6-dimethyl-10-methylenetricyclo[4.3.1.02,9]deca-7-en-4-one.
A Theoretical Approach to the Dielectric Relaxation of Alcohol Solutions
Authors: Minami Ryuichi , Itoh Koichi , Sato Hiroshi , Takahashi Hiroaki , Higasi Keniti
Published: July 2006

The dielectric relaxation mechanism of primary alcohols in solutions of various solvents with and without a hydrogen-bonding capacity was theoretically studied using the concept of the chemical equilibrium between hydrogen-bonded chain multimers and that between the multimers and solvents. The dipole-inversion processes originating from the successive rotation of the hydroxyl groups of the hydrogen-bonded multimers were considered to play the dominant role in the dielectric relaxation of alcohol solutions. By applying the one-dimensional random-walk process to the dipole inversion, we estimated the effect of dilution upon the dielectric relaxation times of primary alcohol in solution. The results of our calculation appear to explain the experimental data.
A Sensitive Atomic Absorption Spectrometric Method for Copper Employing the Direct Introduction of Chelating Resin into a Carbon Tube Atomizer
Authors: Isozaki Akinori , Soeda Naoki , Utsumi Satori
Published: July 2006

A new and simple method for the determination of ppb levels of copper by electrothermal atomic absorption spectrometry was established. The main feature of the proposed method is that chelating resin, a preconcentration agent for copper, is introduced directly as a “resin-suspension” into the carbon tube atomizer without drying and weighing of the resin. To a 250 cm3 sample solution containing up to 1.0 μg of copper, 0.10 g of chelating resin (below 400 mesh) is added, and the mixture is stirred for about 20 min. After the separation of the resin from the aqueous phase through a membrane filter, 5.0 cm3 of resin-suspension is prepared by adding water to the resin. Then, 10 μdm3 (resin: 0.2 mg) of the suspension is introduced into an atomizer, and the copper peak-height is measured under the optimum operating conditions. The calibration graph was linear over the concentration range from 0.1 ppb to 4.0 ppb of copper. The relative standard deviation was 2.3% from 10 repeated measurements; a mean value of 1.08 ppb copper was obtained for a sea water sample.
Structural Interpretation of Plasma-polymerized Tetrafluoroethylene
Authors: Hozumi Keiichiro , Kitamura Keisuke , Kitade Tatsuya
Published: July 2006

Structural interpretation of plasma-polymerized tetrafluoroethylene produced in a glow discharge chamber is given by referring to 19F-NMR and IR spectroscopy, elemental analysis, and number-average molecular weight determination. The polymer is hardly soluble in the usual organic solvents because of its highly branched structure, making NMR spectroscopy and molecular weight determination impossible. However, the polymer is soluble in 1,2-dibromo-1,1,2,2-tetrafluoroethane and the following structural interpretation could be obtained. The number-average molecular weight is 3600 for the majority of the polymer, consisting of 96 carbon and 129 fluorine atoms within a unit molecule. The IR spectrum shows evidence of some C=C groups and the 19F-NMR spectrum a highly branched and cross-linked structure in which a large number of quaternary carbons are involved in the polymer matrix as compared with CF2 and CF carbons. The plasma-polymerized tetrafluoroethylene has been characterized in a somewhat different way from the plasma-polymerized ethylene, involving a small number of quaternary carbons.
Formose Reactions. XIV. A Selective Formose Reaction in the Presence of a Slight Amount of Calcium Ions
Authors: Shigemasa Yoshihiro , Taji Tsuyoshi , Waki Eiichi , Nakashima Ruka
Published: July 2006

It was found that a formose reaction in the presence of small amounts of calcium and d-fructose gave rise to three products, 2-(hydroxymethyl)glycerol, 3-(hydroxymethyl)pentitol, and 2,4-bis(hydroxymethyl)pentitol, with a high selectivity. Various factors affecting the selectivity were also discussed: [Ca], pH, [d-fructose], the reaction temperature, co-catalysts, and metal hydroxides. The amount of formaldehyde relative to [Ca] is the most important factor in obtaining the selective formation of the three-branched sugar alcohols. Under these reaction conditions, the α,β-enediol structure is required in an effective co-catalyst for the formose reaction. 2-(Hydroxymethyl)glycerol, 3-(hydroxymethyl)pentitol, and 2,4-bis(hydroxymethyl)pentitol were formed with a high selectivity in the formose reactions catalyzed by KOH, Mg(OH)2, Fe(OH)3, and LiOH.
Kinetic Study on the Reaction of (Arylthio)trimethylsilanes with Phenacyl Bromide Giving Aryl Phenacyl Sulfides and Bromotrimethylsilane
Authors: Kozuka Seizi , Higashino Tetsuji , Kitamura Takuro
Published: July 2006

A kinetic study has been conducted on the reactions of (arylthio)trimethylsilanes with phenacyl bromide giving aryl phenacyl sulfides and bromotrimethylsilane. Remarkably large positive substituent effect (ρ=+2.2) and large negative entropy of activation were observed for the reaction. A mechanism involving 5-coordinated silicon intermediate prior to the rate-determining heterolysis of the Si–S bond has been suggested for the reaction based on the kinetic results.
Polarographic Studies on Oxygen Transport by Human Hemoglobin in Buffer Solutions
Authors: Hayashi Katsumi , Takagi Masanosuke
Published: July 2006

Oxygen transport by human hemoglobin (Hb) to an electrode surface with hypo-oxygen partial pressure has been studied by the polarographic technique. The oxygen reduction current in Hb solution open to the atmosphere increased linearly with Hb concentration up to ca. 2 mM (1 M=1 mol dm−3) heme. The current was ascribed to free and Hb bound oxygen. The increase in current with Hb concentration was attributed to the increasing oxygen supply to the electrode from oxygen bound Hb (oxyhemoglobin;oxyHb). Changes in temperature and pH largely affected the current, corresponding to the change in dissociation rate of oxygen from oxyHb. The relation between the current due to oxyHb and the apparent first order rate constant of the dissociation (k) measured by the stopped-flow method implies two different rate-determining steps of oxygen transport by Hb. When k exceeded ca. 60 s−1, the limiting step altered from the dissociation of oxygen to the diffusion of Hb molecules. It is concluded that the oxygen transport by Hb on physiological conditions is controlled by the diffusion of Hb. The diffusion coefficient of Hb in 20 mM heme as found in erythrocytes was estimated to be 5.8×10−8cm2 s−1 at 25 °C and pH 7.4.
Synthesis of (+)-11-Hydroxyabieta-2,8,11,13-tetraen-1-one
Authors: Matsumoto Takashi , Imai Sachihiko , Yuki Shuhei
Published: July 2006

Treatment of methyl (+)-11-oxo-13β-abieta-8-en-18-oate with copper(II) bromide and lithium bromide afforded the corresponding phenol derivative, which was methylated to methyl 11-methoxyabieta-8,11,13-trien-18-oate (7). The same compound was also prepared from methyl (+)-7,11-dioxo-13β-abieta-8-en-18-oate via methyl 11-hydroxy-7-oxoabieta-8,11,13-trien-18-oate, its methyl ether, and methyl 11-methoxyabieta-6,8,11,13-tetraen-18-oate. The Grignard reaction of 7 with phenylmagnesium bromide followed by treatment with lead tetraacetate and subsequent oxidation with selenium dioxide afforded 11-methoxy-19-norabieta-4(18),8,11,13-tetraen-3α-ol (12), which was converted to 11-methoxy-19-norabieta-8,11,13-trien-3-one (20) by catalytic hydrogenation, Jones oxidation, and isomerization. The compound 20 was also obtained by Birch reduction of 11-methoxy-19-norabieta-4,8,11,13-tetraen-3-one prepared from 12  via 11-methoxy-19-norabieta-4,8,11,13-tetraen-3α-ol. Subsequently, the compound 20 was transformed to 11-methoxyabieta-1,8,11,13-tetraen-3-one (27) by a series of reactions: acetalization, demethylation, hydrolysis, acetylation, bromination, dehydrobromination, and methylation. Finally, the compound 27 was converted to the title compound, (+)-11-hydroxyabieta-2,8,11,13-tetraen-1-one (1), by oxidation with alkaline hydrogen peroxide, heating with hydrazine hydrate, Jones oxidation, and demethylation. Although the synthetic (+)-1 was shown to be different from natural shonanol, the spectral analyses of the synthetic structural isomers showed the structure of shonanol to be 12-hydroxyabieta-2,8,11,13-tetraen-1-one.
The Coordination of the Perchlorate Ion. I. The Crystal and Molecular Structure of Bis(perchlorato)bis(pyrazine-2,3-dicarboxamide)copper(II)
Authors: Sekizaki Masao
Published: July 2006

Bis(perchlorato)bis(pyrazine-2,3-dicarboxamide)copper(II) has been prepared, and its crystal and molecular structure has been determined by the X-ray diffraction and the infrared spectroscopic methods. The crystals are triclinic with a space group P\bar1; a=10.959(4), b=6.970(3), c=7.666(3) Å, α=116.63(3), β=78.14(5), and γ=97.27(5)°, and Z=1. The refinement of the crystal structure has been carried out by a block-diagonal least-squares method to give R=0.054 for 1727 non-zero reflections. The complex is centrosymmetric, with the two bidentate ligand molecules chelating to the copper atom in trans positions through the amide oxygen and pyrazine nitrogen atoms to form a square-plane. The two perchlorate ions coordinate weakly to the copper atom through the oxygen atoms from the top and bottom of this plane; thus, an elongated octahedron is formed. The complex molecules are connected to one another by N–O type hydrogen bonds to form a three-dimensional network. The infrared spectrum has been compared with that of the chloride complex. The KBr region clearly show the symmetry depression of the perchlorate ion from Td to C3v on coordination.
Catalysis by Alkaline Earth Metal Oxides. III. X-Ray Photoelectron Spectroscopic Study of Catalytically Active MgO, CaO, and BaO Surfaces
Authors: Inoue Yasunobu , Yasumori Iwao
Published: July 2006

X-Ray photoelectron spectroscopy was used to reveal the surface states of MgO, CaO, and BaO oxides, which are catalytically active for ethylene hydrogenation. The catalytic activity of CaO exposed to H2O changed with an increase in the temperature of evacuation in a way similar to that of Ca(OH)2 decomposed by heat treatment. The photoelectron spectrum of CaO evacuated at 1223 K showed a peak of O Is at 529.6 eV, while those of Ca 2p3⁄2 were at 346.3 eV and Ca 2p1⁄2 at 349.8 eV. The adsorption of H2O at room temperature gave rise to an additional peak of O Is at 532.4 eV and one of Ca 2p3⁄2 at 348.6 eV, which were attributed to a Ca–O–H structure. With an increase in the temperature of evacuation from 553 to 1053 K, at which the catalytic activity attained a maximum, the latter O Is peak shifted to the lower binding-energy side by 0.4 eV, and the corresponding Ca 2p peak became broader. These spectral variations were ascribable to the formation of O− species. Evacuation above 1273 K destroyed both the catalytic activity and characteristic peaks. BaO provided three O Is peaks, at 528.5, 530.6, and 532.1 eV, after evacuation at 1373 K; these peaks were assigned to lattice oxygen of the oxide, O−, and OH− species respectively. The Ba 4d spectra showed correspondingly superposed peaks. The XPS peak due to O− was observed only when BaO was evacuated at temperatures high enough to generate the catalytic activity. Such spectral features were less pronounced in the case of MgO. The structural analysis of CaO showed that the coordinatively unsaturated cations also play a role in the catalytic hydrogenation. On the basis of these findings, it was concluded that a combined structure of O− and the cations is responsible for the hydrogenation activity.
Spin Densities in the Radical Anion of 3,3′-Bipyridine
Authors: Fujita Hideo , Deguchi Yasuo
Published: July 2006

The ESR spectrum of the radical anion of 3,3′-bipyridine has been measured. The hfs constants agree with the calculated values based on the spin densities using the McLachlan method.
Photolysis of Sodium Arenesulfonates in Alkaline Dimethyl Sulfoxide Solutions
Authors: Suzuki Nobutaka , Ito Kinya , Izawa Yasuji
Published: July 2006

Photolysis of arenesulfonates in alkaline DMSO under air gave the corresponding desulfonation products, arenes, presumably via the π-π* excited triplet state.
N-Trifluoroacetylimidazoles as a Reagent for Converting Aldoximes into Nitriles under Mild Conditions
Authors: Keumi Takashi , Yamamoto Takayoshi , Saga Hiroshi , Kitajima Hidehiko
Published: July 2006

It was found that N-trifluoroacetylimidazole was an excellent reagent for the intramolecular dehydration of aldoximes to give nitriles uner mold conditions.
Preparation and Oxidation of Europium(II) Niobium Bronze EuxNbO3−y
Authors: Ishikawa Kenji , Adachi Gin-ya , Tanida Midori , Shiokawa Jiro
Published: July 2006

Mixed oxides containing bivalent europium, EuxNbO3−y (0.5<x<1.0), were synthesized by the solid state reaction of Eu2O3, Nb2O5, and Nb powder. The structural change of EuxNbO3−y from a tetragonal to cubic form takes place at x=0.65. The mechanism of oxidation for the bronzes was studied. Each bronze shows different behavior in oxidation, the cubic bronze giving an amorphous phase and the tetragonal bronze complex crystalline products. EuNbO4 was crystallized from both the amorphous and crystalline phases at 950 K and 1070 K, respectively. TG-DTA and magnetic studies indicated that the oxidized phases play an important role in the rate-determining step of oxidation for the bronzes.
High Resolution Proton Nuclear Magnetic Resonance Studies of Solute Molecules in the Poly(vinylalcohol) Gel Medium
Authors: Fujiwara Shizuo , Fujikura Ryo , Ogino Takashi , Tanaka Michiko , Arata Yoji
Published: July 2006

It was shown that a pair of spectra is observed for each solute in the medium of poly(vinylalcohol) gels swollen in water. Each of the spectra was assigned as originating from the solute in the PVA gel itself and that in the bulk solution surrounding the gel. It was concluded that the chemical shift difference is primarily explained in terms of the difference in the volume susceptibility of the PVA gel and the bulk solution. It was observed in the case of nicotinamide adenine dinucleotide (NAD) that the chemical shift differences are different for different functional groups. We suggest that this observation reflects a contribution from intermolecular interaction between PVA gel and the NAD molecule.
Dynamic Properties of the Phosphorescent Triplet State of 9H-Thioxanthen-9-one (Thioxanthone) from Optically Detected Magnetic Resonance Spectroscopy
Authors: Suga Kazuhiko , Kinoshita Minoru
Published: July 2006

A variety of optically detected magnetic resonance (ODMR) experiments have been performed on the lowest excited triplet state of 9H-thioxanthen-9-one at 1.4 K. The absorption and phosphorescence excitation spectra were also measured to supplement the ODMR studies. The results were analyzed to determine the mechanisms responsible for the radiative decay and intersystem crossing processes. The z sublevel has large activity in vibronic bands due to non-totally symmetric vibrations. The intensity mainly comes from mechanisms involving vibronic coupling between 1n,π* and 1π,π* states. The y sublevel is selectively affected by the introduction of the sulfur atom, because of the increased importance of spin orbit coupling with 1σ′,π* state which is largely localized on the thioether group.
Kinetic Studies of the Oxidation Reactions of o-, m-, and p-Benzenediols with Tris(1,10-phenanthroline)iron(III). An Estimation of the Redox Potentials of the Organic Radicals by Application of the Marcus Theory
Authors: Kimura Masaru , Yamabe Shinichi , Minato Tsutomu
Published: July 2006

Kinetic studies of the oxidation of o-, m-, and p-benzenediols (H2A) by tris(1,10-phenanthroline)iron(III) were made in dilute perchloric acid solution at an ionic strength of 1.0 mol dm−3 at four temperatures between 10 and 30 °C. The second-order rate constants (k0) which follow the observed rate law of –d [Fe(phen)33+]/dt=k0[Fe(phen)33+][H2A] were determined under varied conditions. The order of the rate constants was m-<o-<p-benzenediols, with the ratio being approximately 1 : 103 : 104. By the application of the Marcus theory to the kinetic parameters obtained, the standard redox potentials of the dihydroxyphenyl radicals (H2A\underset.+) were estimated in 0.11 mol dm−3 perchloric acid solution to be 1.41, 1.10, and 0.97 V for m-, o-, and p-benzenediols, respectively. The energies of the highest occupied molecular orbitals for the H2A molecules (εHOMO) were calculated to be −0.4468, −0.4332, and −0.4224 a.u. for m-, o-, and p-benzenediols, respectively. The differences of the total electronic energies between H2A\underset.+ and H2A molecules (ΔET) were calculated to be 0.4183, 0.4033, and 0.3957 a.u. for m-, o-, and p-benzenediols, respectively. Thus, the standard redox potentials of the free-radicals estimated are found to be well correlated with the HOMO energies and also with the differences of the total electronic energies between the cation radicals and the parent molecules.
Kinetics and Equilibrium of the Reaction between Bis(trifluoroacetylacetonato)palladium(II) and Tri-o-tolylphosphine
Authors: Matsumoto Shinichi , Kawaguchi Shinichi
Published: July 2006

Tri-o-tolylphosphine reacts with bis(trifluoroacetylacetonato)palladium(II), Pd(tfac)2, to convert one of the chelating ligands into the unidentate state, resulting in Pd(tfac)(tfac-O)P(o-tolyl)3. The reaction was studied by a spectrophotometric method. The equilibrium constant was determined at several temperatures, K being 1.38×103, 4.35×103 dm3 mol−1 and more than 109 dm3 mol−1 in benzene, dichloromethane, and methanol, respectively, at 25 °C. In the presence of excess phosphine, the reaction proceeds as a pseudo first order reaction to attain equilibrium. The forward and reverse rate constants, k1 and k−1, were obtained as 0.172 dm3 mol−1 s−1 and 1.22×10−4 s−1 in benzene and 2.28 dm3 mol−1 s−1 and 4.9×10−4 s−1 in dichloromethane at 25 °C, respectively. In methanol the forward rate was measured under irreversible pseudo first order conditions and conforms with the usual two term rate law, kobsd⁄s−1=2×10−3+56.6[P(o-tolyl)3]. The remarkable dependence of K and k1 on the nature of solvent is related to the hydrogen bonding interaction between the carbonyl group of the coordinated tfac anion and a solvent molecule.
Studies on Window Sweep Chronopotentiometry. I. Fundamental Concept, Methodology, and Analytical Application
Authors: Kato Yoshikiyo , Yamada Akifumi , Yoshida Norimasa , Unoura Kei , Tanaka Nobuyuki
Published: July 2006

Window sweep chronopotentiometry, a new galvanostatic method, has been worked out, the electronic circuit of a window sweep chronopotentiograph and digital simulation of the window sweep chronopotentiogram being presented. Analytical application demonstrating the increase in sensitivity of the galvanostatic method for quantitative analysis is presented.
Nucleophilic Reactions of Hydrazido(2–) Complexes of Molybdenum and Tungsten with Succinyl Dichloride and Phenyl Isocyanate
Authors: Iwanami Kiyotaka , Mizobe Yasushi , Takahashi Tamotsu , Kodama Teruyuki , Uchida Yasuzo , Hidai Masanobu
Published: July 2006

Nucleophilic attack of the WNNH2 group in the hydrazido(2-) complex [WF(NNH2)(dpe)2][BF4] (dpe=Ph2PCH2CH2PPh2) on succinyl dichloride gives a novel ethanedioylhydrazido(2-) complex, [WF(NNCOCH2CH2CO)(dpe)2][BF4]. X-Ray structural analysis shows that the carbon, nitrogen, and oxygen atoms of the ethanedioylhydrazido(2-) ligand lie nearly in the same plane, indicating sp2 character of the nitrogen atom bearing the two carbonyl groups. Phenyl isocyanate also undergoes nucleophilic attack by the hydrazido(2-) complex [MBr(NNH2)(dpe)2]Br (M=Mo or W) to yield the phenylsemicarbazido(2-) type complex, [MBr(NNHCONHPh)(dpe)2Br. Treatment of the semicarbazido(2-) complex with triethylamine gives a new diazenido complex [MBr(NNCONHPh)(dpe)2].
The Thermal Decomposition of N,O-Diacyl-N-t-butylhydroxylamines. II. Thermal Rearrangement of O-Acyl-N-[2-(methylthio)-benzoyl]-N-t-butylhydroxylamines
Authors: Uchida Yuzuru , Kobayashi Yusho , Kozuka Seizi
Published: July 2006

Several O-acyl-N-[2-(methylthio)benzoyl]-N-t-butylhydroxylamines (1) were prepared and their thermal decompositions were studied. The thermal decomposition of 1 at 200 °C in o-dichlorobenzene gave N-t-butyl-2-(acyloxymethylthio)benzamide (4), the carboxylic acid derived from the acyl part of 1, and 2-t-butyl-1,2-benzothiazol-3(2H)-one as the main products, together with small amounts of 4H-3,1-benzoxathiin-4-one, N-t-butyl-2-(methylthio)benzamide, methyl ester of the carboxylic acid, and N-t-butylamide. The benzamide (4) was found to be an initial product of the thermolysis and the subsequent decomposition gave the carboxylic acid and other products. Pummerer type reaction, via acylaminosulfonium ion as the intermediate, was suggested for the thermal decomposition of 1 since similar products were also obtained by the Pummerer reaction of N-t-butyl-2-(methylsulfinyl)benzamide with acylating reagents.
Thermal Reactions of Metal Complexes under Quasi-isothermal and -isobaric Conditions. II Formation of Triamminetrihalogenochromium(III) Complexes via the Decomposition of Hexaammine, Pentaamminehalogeno, and trans-Tetraamminedihalogeno Complexes
Authors: Ueno Hitoshi , Uehara Akira , Tsuchiya Ryokichi
Published: July 2006

The thermal decomposition of the following chromium(III) complexes was investigated in the solid phase by means of Q-derivatograph under quasi-isothermal and -isobaric conditions (Q-conditions) and D-derivatograph under dynamic conditions (D-conditions): [Cr(NH3)6]X3, [CrX(NH3)5]Y2, and trans-[CrX2(NH3)4]Y, where X and Y are chloride and/or bromide ions. The complexes were finally converted into triamminetrihalogeno complexes [CrBrxCly(NH3)3] (x+y=3; x and y=0, 1, 2, or 3) under Q-conditions but decomposed in complicated ways under D-conditions. All the triamminetrihalogeno complexes thus obtained have mer-configuration with respect to the positions of the three halide ions.
Binuclear Metal Complexes, XXXIX. Synthesis and Properties of Binuclear Copper(II) Complexes with [2-(2-Pyridyl)ethylamino]alkanols and [2-(2-Pyridyl)ethylthio]alkanols
Authors: Nakamura Masaaki , Mikuriya Masahiro , Okawa Hisashi , Kida Sigeo
Published: July 2006

Di-μ-alkoxo-bridged binuclear copper(II) complexes, Cu(py-3-3-nno)X, Cu(py-3-2-nso)X, and Cu(py-3-3-nso)X (X=Cl, Br, ClO4, NO3, PF6, BF4), have been synthesized and characterized, where Hpy-3-3-nno, Hpy-3-2-nso, and Hpy-3-3-nso denote 3-[2-(2-pyridyl)ethylamino]-1-propanol, 2-[2-(2-pyridyl)ethylthio]ethanol, and 3-[2-(2-pyridyl)ethylthio]-1-propanol, respectively. It was found that 2-[2-(2-pyridyl)ethylamino]ethanol (Hpy-3-2-nno) cannot form di-μ-alkoxo-bridged binuclear copper(II) complexes owing to the high strain in the fused ring system. These complexes exhibited a band at 22000–27000 cm−1 characteristic of the di-μ-alkoxo-bridged structure, the bands for Cu(py-3-2-nso)X and Cu(py-3-3-nso)X being lower in frequency compared with those for Cu(py-3-3-nno)X. Antiferromagnetic interaction was stronger and reduction potential (Cu(II)–Cu(II)→Cu(I)–Cu(I)) was higher for Cu(py-3-3-nso)X than those for Cu(py-3-3-nno)X. Cu(py-3-3-nso)Cl and Cu-(py-3-2-nso)Br showed two reduction waves at about +0.15 and −0.4 V vs. SCE. These results were discussed in terms of the structure in solution on the basis of conductivity measurements.
Synthesis of New Chiral Phase-transfer Catalysts and Their Application to Michael Additions
Authors: Banfi Stefano , Cinquini Mauro , Colonna Stefano
Published: July 2006

A series of chiral onium salts derived from (l)-(+)-methionine have been examined for the catalysis of Michael additions in phase-transfer conditions. The chemical yields are high, but no asymmetric induction was observed. Catalyst 6 represents the first example of an onium salt anchored to a polimeric matrix having a higher catalytic efficiency than its soluble counterpart.
Optical Resolution of Cyclo-palladated (Dimethylaminomethyl)ferrocene
Authors: Komatsu Takao , Nonoyama Matsuo , Fujita Junnosuke
Published: July 2006

Cyclo-palladated (dimethylaminomethyl)ferrocene has been resolved into optically pure enantiomers via the (S)-proline derivatives. The absolute configuration is assumed by comparing the circular dichroism spectrum with that of similarly cyclo-palladated (S)-[1-(dimethylamino)ethyl]ferrocene of the known configuration. Several optically active derivatives of the cyclo-palladated (dimethylaminomethyl)ferrocene have been prepared and characterized.
Enthalpies of Fusion of Intermediate Compounds, KMgCl3, K2MgCl4, K2BaCl4, KCaCl3, K2SrCl4, K2LaCl5, K3PrCl6, K3NdCl6, KGd3Cl10, and KDy3Cl10
Authors: Hattori Takeo , Igarashi Kazuo , Mochinaga Junichi
Published: July 2006

The enthalpies of fusion were measured on the intermediate compounds of the binary systems of KCl and some other chlorides. These were compared with the values calculated using Cp of the component salts according to the additivity. The enthalpies of fusion measured were in good agreement with calculated in K2LaCl5 and K2BaCl4.
Synthesis of 7-Halo-6H-benz[cd]azulen-6-ones
Authors: Kuroda Shigeyasu , Sugimori Masaru , Kawahigashi Shinya , Matuzaki Nobuo , Nishiyama Toshihiro , Hirooka Syuzi
Published: July 2006

7-Bromo-6H-benz[cd]azulen-6-one, 7-Chloro-6H-benz[cd]azulen-6-one and its derivative were prepared in four steps starting from tetrahydroacenaphthene. Formation of the corresponding cations in strong acid is suggested on the basis of 1H NMR and UV spectra.
Preparation and Absorption and Circular Dichroism Spectra of Cobalt(III) Complexes with N,N,N′,N′-Tetrakis(2-aminoethyl)-1,2-ethanediamine, -1,3-propanediamine, -1,4-butanediamine, and -(R,R)-and -(R,S)- 2,4-pentanediamine
Authors: Hata Kazumasa , Doh Myung-Ki , Kashiwabara Kazuo , Fujita Junnosuke
Published: July 2006

Cobalt(III) complexes of new sexidentate ligands,N,N,N′,N′-tetrakis(2-aminoethyl)-1,3-propanediamine (ttn), -1,4-butanediamine (ttmd), and -(R,R)- and -(R,S)-2,4-pentanediamine (tptn) were prepared and resolved except the RR-tptn complex which formed the Δ-isomer stereoselectively. The monocyano complexes of N,N,N′,N′-tetrakis(2-aminoethyl)-1,2-ethanediamine (ten) and ttn, in which the ligands act as a quinquidentate, were also prepared. Absorption and CD spectra of these complexes and the known [Co(ten)]3+ complex were compared with one another. The first d-d absorption bands of the sexidentate complexes, [Co(A)]3+ are shifted to smaller wave numbers in the order, ttn>ten>ttmd for A, but those of [Co(CN)(HA)]3+ are in the reverse order, ten>ttn. The d-d absorption bands of [Co(RS-tptn)]3+ which contains one axial methyl group show the remarkable red shift and the hyperchromic effect as compared with those of [Co(RR-tptn)]3+ with two equatorial methyl groups.
Light Scattering Study of the 12-Hydroxyoctadecanoic Acid and Benzene Mixture in the Gel State
Authors: Ito Nobuyuki , Yudasaka Masako , Fujiyama Tsunetake
Published: July 2006

The structure of the 12-hydroxyoctadecanoic acid-benzene gel was studied by the use of the light scattering spectrometer. The scattering angular dependence of the scattering intensity and the time correlation function of the electric field were measured. It was found that the coarse mesh network and the fine mesh network coexist in this gel. The former was detected by the intensity measurement, while the latter was detected by intensity-fluctuation spectroscopy. The usefulness of the light scattering technique was emphasized.
The Rapid Determination of Sulfide, Thiosulfate, and Polysulfide in the Lixiviation Water of Blast-furnace Slag by Means of Argentimetric Potentiometric Titration
Authors: Satake Hiromu , Hisano Takeo , Ikeda Sanae
Published: July 2006

Sulfide, thiosulfate, and polysulfide ions in their mixtures were determined potentiometrically with a silvernitrate standard solution. These three species can be precisely determined from two titrations for each sample with the coefficient of variation of 0.3% at the concentration level of 5×10−4 M (1 M= 1 mol dm−3). One aliquot is titrated, after making the titrand acidic with an acetate buffer (pH=4), to get the end points of the sulfide and thiosulfate ions respectively, in the presence of free sulfur. The other is titrated, after the sulfitolysis of the sample solution, to show the end points of the sulfide and thiosulfate (the original thiosulfate plus the thiosulfate which is formed from polysulfide) ions in the presence of excess sulfite. The addition of calcium nitrate is effective in making the end points clear and accurate. This method was applied to determine these species in lixiviation water of blast-furnace slag.
Reactions of the Bis(β-diketonato)palladium(II) Complexes with Various Nitrogen Bases
Authors: Okeya Seichi , Sazaki Hiroyuki , Ogita Michiyo , Takemoto Takako , Onuki Yukio , Nakamura Yukio , Mohapatra B K , Kawaguchi Shinichi
Published: July 2006

Reactions of the bis(β-diketonato)palladium(II) complexes with various nitrogen bases (L) afforded [Pd(β-dik)L2](β-dik), [PdL4](β-dik)2, or [Pd(β-dik)(β-dik-C)L] according to the natures of L and β-diketonate anions. Less basic ligands such as 1,1,1,5,5,5-hexafluoro- and 1,1,1-trifluoro-2,4-pentanedionates are readily removed by L to the outer sphere. Tendency of preferring the central-carbon-bonded state of the β-diketonate anion is related with the keto-favoring nature of its conjugate acid. Excess primary amines and pyridines can displace both of the β-diketonate ligands but secondary amines only one. These two types of compounds containing the 2,4-pentanedionate anion in the outer sphere undergo prompt deuteration of methine and amine protons by CDCl3. Tribenzylamine and 2,6-diphenylpyridine react with bis(1,1,1,5,5,5-hexafluoro-2,4-pentanedionato)palladium(II) to afford orthometallated products.
Photo-promoted Hypochlorite Oxidation of α-Amino Acids. Kinetics and Irradiation Effect for the Strecker Degradation
Authors: Ogata Yoshiro , Kimura Makoto , Kondo Yoshinori
Published: July 2006

Hypochlorite oxidation of simple α-amino acids (the Strecker degradation) in aqueous solutions has been studied in the dark and under UV-irradiation. UV-spectra, iodometry, and amino acid determination (2,4-dinitrofluorobenzene method) suggest that the intermediate N-chloro amino acid is formed quickly at an initial stage, then its slow oxidative decomposition takes place to give aldehyde, carbon dioxide, and ammonia. The mechanism is also supported by the fact that the oxidation follows the first-order rate expression; −d[RCH(NH2)CO2H]⁄dt=k[1[RCH(NHCl)CO2H]. UV-irradiation was found to promote remarkably the degradation of N-chloro amino acid. When equimolar amounts of amino acid and hypochlorite were used, the products such as unreacted amino acid, ammonia, and aldehyde were analogous to those of the dark reaction. The use of a large excess of hypochlorite under irradiation enables complete oxidative degradation of amino acid to carbon dioxide,, water, and nitrogen. Its application to waste water treatment is discussed.
Effects of Chelated and Non-chelated Transition Metal Ions on the Photoreactions of Pyridinecarboxylic Acids in Aqueous Solutions
Authors: Sugimori Akira , Takada K\={o}tar\={o} , Kimura Tsutomu , Kamimura Junji
Published: July 2006

Iron(III) and copper(II) chelated by 2-pyridinecarboxylate bring about the photochemical decarboxylation of the ligand via the electron transfer from carboxylate to metal ions to give pyridine and 2,2′-bipyridine (for Fe(III)) or 2-pyridinol (for Cu(II)). In the presence of iron(III), ruthenium(III), and copper(II), 3-pyridinecarboxylic acid gives photochemically 2,2′-bipyridine-3,5′-dicarboxylic acid without decarboxylation. 4-Pyridinecarboxylic acid is photo-resistant both in the presence and in the absence of iron(III) and copper(II).
Asymmetric Hydrogenation Catalyzed by the (Achiral Base)bis(dimethylglyoximato)cobalt(II)–Chiral Cocatalyst System. The Preparation of a New Type of Chiral Cocatalyst and Its Application to the Asymmetric Hydrogenation of Methyl N-(Acetylamino)acrylate and Benzil
Authors: Takeuchi Seiji , Ohgo Yoshiaki
Published: July 2006

As a new type of chiral cocatalyst in the achiral base-coordinated bis(dimethylglyoximato)cobalt(II)–chiral cocatalyst system, tertiary amines with an amide group at α- or β-carbon were prepared, and asymmetric hydrogenation was examined by using them. The optical yield reached 34.5% enantiomeric excess(ee) by using N-[(2S,3S)-2-acetoxy-3-dimetnylamino-3-phenylpropionyl]-(R)-α-methylbenzylamine; this is the highest value attained so far in the asymmetric hydrogenation of methyl N-(acetylamino)acrylate with this system. The enantioselectivity in the hydrogenation of methyl N-(acetylamino)acrylate was reversed with a configurational alteration of the α-methylbenzylamine moiety of N-[N,N-dimethyl-(S)-phenylalanyl]-α-methylbenzylamine, while it was not reversed in the hydrogenation of benzil by the configurational alteration. From these facts, it is deduced that the hydrogen bond between amide groups of the chiral amino carboxamides and methyl N-(acetylamino)acrylate may act as an attractive force to enhance the enantioselectivity of the asymmetric hydrogenation.