bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pulse Mode Product-Yield-Detected ESR on the Photoreduction of Anthraquinone in SDS Micellar Solution: Reaction Control by a Microwave Pulse
Authors: Okazaki Masaharu , Toriyama Kazumi 
Published: August 2006

Abstract
A pulse mode PYESR (Product-Yield-Detected ESR) spectrometer was developed by using an excimer laser and a TWT microwave amplifier as the components. The effect of ESR transition of the transient radical pair on the yield of the spin adduct of one of the component radicals was observed at a high microwave power of up to 16 W without microwave heating of the solvent. The spin adduct yield of the SDS radical in the photoreduction of anthraquinone in SDS micellar solution initiated by a laser pulse of 308 nm was modulated by up to 45% by a microwave pulse of 10 μs with a peak power of 16 W, which is resonant on the ESR transition of the transient anthrasemiquinone radical. The ESR spectrum of the radical pair was obtained by tracing this modulation as a function of the magnetic field, under which the photoreaction occurred. From the dependence of the product yield on the microwave pulse duration, we could obtain a time profile of the appearance of the transient radical pair.
The Hydration Structure of NO3− in Concentrated Aqueous Sodium Nitrate Solutions
Authors: Kameda Yasuo , Saitoh Hiroki , Uemura Osamu 
Published: August 2006

Abstract
Time-of-flight neutron diffraction measurements have been carried out on 10 mol% NaNO3 solution in D2O. The isotopic substitution technique was applied to nitrogen atoms in the solution in order to determine both hydration structure around the nitrate ion, NO3−, and intramolecular geometry of NO3− in the aqueous solution. It has become apparent that there exist 5.0 ± 0.5 water molecules coordinated to NO3− with the intermolecular distance r(N···D) = 2.80 Å. The intramolecular bond distance and the root mean square amplitude in NO3− have been determined to be rNO = 1.253 ± 0.006 Å and lNO = 0.058 ± 0.008 Å, respectively.
Crystal Structure and Conductivity of Chiral Radical Ion Salts (Me2ET)2X
Authors: Matsumiya Shigeki , Izuoka Akira , Sugawara Tadashi , Taruishi Tomohiro , Kawada Yuzo , Tokumoto Madoka 
Published: August 2006

Abstract
Radical ion salts of both chiral (R,R) and racemic organic donor, (Me2ET)2X (Me2ET = trans-dimethylbis(ethylenedithio)tetrathiafulvalene, X = PF6, ClO4, and ReO4) were electrochemically prepared and their crystal structures were analyzed. The donor molecules are stacked in a twist-type column to reduce steric repulsion caused by methyl groups. The anions are contained in the cavities formed both by methylated and unsubstituted ethylene groups of the donor molecules, and their orientation is fixed through hydrogen bonds to methine and methylene protons. The structural difference between chiral and racemic salts is discussed. In spite of the difference in the crystal structure, their conductivity is almost identical, reflecting similarity of side-by-side S–S contacts between the donor molecules.
Voltammetric Study on the Transfer of Alkali and Alkaline Earth Metal Ions at the Aqueous/Organic Interface Facilitated by Phosphine Oxides
Authors: Ogura Kaoru , Kihara Sorin , Umetani Shigeo , Matsui Masakazu 
Published: August 2006

Abstract
The transfer of alkali metal and alkaline earth metal ions (Mz) from aqueous to nitrobenzene (NB) phases, facilitated by mono-, bi-, or tridentate phosphine oxides (PO), was investigated in terms of the voltammetry for the ion transfer across the interface of two immiscible electrolyte solutions. The complex formation of Mz with PO in the vicinity of the interface and the transfer process of Mz were clarified based on an analysis of the current-potential curves, while referring to information obtained from the synergistic ion-pair extraction of Mz(ClO4−)z with PO. The stability constants of Mz–PO complexes in NB were evaluated based on the half-wave potentials in the ion transfer voltammograms, and were related to the properties of Mz and PO.
Formation of Cyclopropanes and Epoxides from Vinylselenonium Salts
Authors: Watanabe Yoshihiko , Ueno Yoshio , Toru Takeshi 
Published: August 2006

Abstract
Treatment of vinyl- and (5-oxo-1-cyclopentenyl)selenonium tetrafluoroborates 2 and 4 with a variety of carbanions gives cyclopropane derivatives 3 and 5 in good yields. The reaction of vinylselenonium salt 2 with sodium alkoxides in the presence of aldehydes gives various kinds of glycidyl ethers 7 in excellent yields. The reaction of 2 with hydroxyacetone in the presence of K2CO3 affords cyclized products 8 and 9 together with the Michael addition product 10.
Dehydrooligopeptides. XV. Useful Syntheses of Dehydrodipeptides by the Enzymatic Coupling of α-Dehydroglutamate with Various α-Amino Acid Amides Using Proteases
Authors: Shin Chung-gi , Seki Masashi , Kakusho Takeshi , Takahashi Nobuyuki 
Published: August 2006

Abstract
Novel enzymatic syntheses of various dehydrodipeptides by the coupling of α,γ-dimethyl N-benzyloxycarbonyl(Z)-α-dehydroglutamate [Cbz–ΔGlu(OMe)–OMe; 1] with α-amino acid amides (H–AA–NHR) using proteases, such as papain and α-chymotrypsin A (CT), are described. It was found that there was conspicuous difference between the catalytic actions of papain and CT toward 1. In the case of papain, the selective coupling of α-ester of 1 with H–AA–NHR took place to give Cbz–ΔGlu(OMe)–AA–NHR, while in the case of CT the coupling of γ-ester of 1 proceeded predominantly to give Cbz–ΔGlu(AA–NHR)–OMe. The present study suggests that both papain and CT may become a versatile tool for the organic synthesis by the coupling of not only ΔGlu derivatives but also the other α-dehydroamino acids with α-amino acids or peptides.
Electropolymerization of Bis(4-cyano-1-pyridinio) Derivatives for the Preparation of Polyviologen Films on Electrodes
Authors: Saika Tetsuyuki , Iyoda Tomokazu , Shimidzu Takeo 
Published: August 2006

Abstract
Six bis(4-cyano-1-pyridinio) derivatives have been synthesized and deposited onto electrodes by cathodic electropolymerization (ERed = −0.64 — −0.74 V vs. SCE) under basic conditions. The deposited films were constructed of polyviologens that showed characteristic electrochromisms with colorless or slightly yellow to blue- or red-violet. The derivative was reduced to 4-cyano-1,4-dihydro-4-pyridyl radicals, which were coupled successively to form a polyviologen film on the electrode with an elimination of cyanide ions. Characteristically, the polyviologen films deposited by this electropolymerization were insoluble in water and common organic solvents with a spontaneous cross-linking. Especially, a polyanion as a supporting electrolyte forced the polyviologen to form a polyelectrolyte complex in situ. The current efficiency of surface coverage with the polyanion electrolyte (23% in the typical case) was about four-times larger than those with monomeric anions.
Regioselectivity of Reductive Cleavage of Methyl 4,6-O-Benzylidene-3-deoxyhexopyranosides Containing Fluorine at the 2- or 3-Position with LiAlH4–AlCl3
Authors: Mori Yoko , Morishima Naohiko 
Published: August 2006

Abstract
Reductive ring-opening reactions of the 4,6-O-benzylidene derivatives of methyl 3-deoxy-β-d-arabino-, 3-deoxy-α-d-ribo-, and 2-O-benzyl-3-deoxy-α-d-ribo-hexopyranosides with LiAlH4 and AlCl3 in the molar ratio of 4 : 4 gave the 4- and 6-O-benzyl derivatives in a ratio of 7 : 3. The product ratios for the reactions of methyl 4,6-O-benzylidene-2,3-dideoxy-2-fluoro-α-d-arabino- and β-d-ribo-hexopyranosides and methyl 2-O-benzyl-4,6-O-benzylidene-3-deoxy-3-fluoro-α-d-gluco- and β-d-allopyranosides were 3 : 2, 2 : 3, 1 : 1, and 3 : 7, respectively. When the molar ratio of the reagents was 2 : 4, however, the product ratios for the reactions of all the above-mentioned 4,6-O-benzylidene derivatives were approximately equal to 4 : 1. The influence of fluorine at C-2 or C-3, as well as that of the molar ratios of LiAlH4 and AlCl3, on the regioselectivity of the reductive cleavage of 4,6-O-benzylidenehexopyranosides are discussed.
The Arbuzov Reaction of Alkyl Diphenylphosphinites with 10-Methylacridinium Ion. Kinetic Study on the Formation and the Decomposition of Phosphonium Intermediates
Authors: Yasui Shinro , Shioji Kosei , Yoshihara Masakuni , Maeshima Toshihisa , Ohno Atsuyoshi 
Published: August 2006

Abstract
Alkyl diphenylphosphinites (1) react rapidly with 10-methylacridinium iodide (2a) to afford the corresponding phosphonium ions (3), which gradually decompose to phosphine oxide, the expected Arbuzov product. Large difference in the rate of the first (phosphonium-forming) and the second (phosphonium-decomposing) steps enables us independent kinetic investigation for both steps, with which it has been found that the first step obeys second-order kinetics with first-order with respect to 1 and 2a, respectively. The second step proceeds according to either the SN2 mechanism when alkyl substituent in 1 is primary or secondary, in which iodide ion acts as a nucleophile, or the SN1 mechanism when the substituent is tertiary. Closer examination on the first step with activation parameters reveals that the transition state of this step becomes more reactant-like as the substituent in 1 becomes bulkier. For the second step, survey of the activation parameters shows that the breaking of the carbon–oxygen bond in 3 predominates over the formation of the oxygen–phosphorus double bond.
Kinetic Stability as Monomeric Forms of 2-Alkyl-5,6-dihydro-3-thioacetyl-2H-naphtho[1,2-b]thiopyrans
Authors: Moriyama Satoshi , Karakasa Takayuki , Saito Takao , Motoki Shinichi 
Published: August 2006

Abstract
2-Alkyl-5,6-dihydro-3-thioacetyl-2H-naphtho[1,2-b]thiopyrans (2) exist stably in the form of monomers at room temperature, whereas unsubstituented ones at the 2-position are apt to dimerize. Based on the X-ray analysis of (2g), UV spectral study of (2), and on semi-empirical calculations, this difference of the stability could be rationalized mainly by steric reason around the heterodiene C=C–C=S system.
Fluorescence and Fluorescence-Excitation Spectra of Benzo[f]quinoline during the Sol–Gel–Xerogel Transitions of Mixed Silicon–Aluminum Alkoxide Systems
Authors: Mabuchi Toshiaki , Fujii Tsuneo 
Published: August 2006

Abstract
The fluorescence and fluorescence-excitation spectra of doped benzo[f]quinoline (BQ) during the sol–gel–xerogel transitions of two reaction systems of mixed alkoxides that were catalyzed by HCl and NaOH (or NH3) have been observed as a function of time. The mixed alkoxides were comprised of tetraethyl orthosilicate (TEOS) and diisobutoxyaluminum triethyl silicate (SAE) (Si : Al = 10 : 0 and 9 : 1). During the reaction, it was found that BQ forms three different fluorescent species, neutral, protonated, and an ion pair. The neutral form was seen in the first stage of the reaction and emitted a structured fluorescence. The protonated form appeared in the next reaction stage and it gave a broad and structureless band with a peak around 440 nm. The ion-pair form, produced from BQ and an –OH group of –O–Si–O– and/or –O–Si–O–Al–O– networks, appeared in the last stage of the reaction and its fluorescence peak was located at around 400 nm. The ion pair could not be detected in solutions, but it was found in the xerogel state. The appearance and disappearance of the three species of BQ reflect the condition of microenvironment around the doped BQ during the sol–gel reaction of the TEOS and TEOS+SAE systems. Therefore, the measurements of the fluorescence spectra of BQ are useful for the photophysical investigation on the sol–gel–xerogel transitions of systems containing metal alkoxides such as TEOS and TEOS+SAE.
2-(2-Furyl)-3-hydroxy-4H-chromen-4-one as an Analytical Reagent for Molybdenum(VI)
Authors: Dass Rameshwar , Mehta Jaswant Ram 
Published: August 2006

Abstract
2-(2-Furyl)-3-hydroxy-4H-chromen-4-one (FHC) has been used as an analytical reagent for the spectrophotometric determination of molybdenum. Molybdenum(VI) in the presence of several cations except Sb(V), Bi(III), and Ce(IV), anions and complexing agents except oxalate forms a yellow 1 : 2 complex with FHC. The complex was extractable into chloroform from 0.01—0.25 mol dm−3 acetic acid (pH 4.2—2.9) and was stable for 2 h. The complex showed an absorption maximum at 414 nm with a molar absorptivity of 4.99 × 104 dm3 mol−1 cm−1 and Sandell’s sensitivity equal to 0.0019 μg Mo cm−2. Beer’s law was obeyed over the concentration range of 0—2.9 ppm. The equilibrium constant was found to be 6.70 × 10−12. For 1 μg Mo cm−3 the standard deviation was 0.004 with a relative mean error of ±0.7%. The method is simple, selective, precise and rapid and has been applied to the determination of molybdenum in synthetic and standard samples.
Conjugation-Extended Tetrathiafulvalene Analogues Involving a Central Aromatic 5-Membered Heterocyclic Linking Group
Authors: Takahashi Kazuko , Nihira Takayasu , Yoshifuji Masaaki , Tomitani Kensuke 
Published: August 2006

Abstract
Conjugation-extended tetrathiafulvalene analogues, 2,5-bis(1,4-dithiafulven-6-yl)thiophene (2a), 2,5-bis[2,3-bis(methoxycarbonyl)-1,4-dithiafulven-6-yl]thiophene, and 2,5-bis(1,4-dithiafulven-6-yl)furan, involving an aromatic heterocyclic linking group have been synthesized by the Wittig condensation reaction of 2,5-thiophene- and 2,5-furandicarbaldehydes with 1,3-dithiol-2-ylidenetributylphosphorane and its 4,5-bis(methoxycarbonyl) derivative. The electrochemical redox properties of these compounds in solution have been investigated by cyclic voltammetry in order to evaluate the effect of the linking group on the donating ability and the thermodynamic stability of the radical cations. Whereas the radical cations are not so stable, complexes of 2a with 2,3-dichloro-5,6-dicyano-p-benzoquinone and iodine were found to show relatively high conductivities ((1.0—1.1) × 10−3 S cm−1) on a compressed pellet at room temperature.
Tris(trimethylsilyl)silyl Radical Induced Bicyclization of 1,6-Dienes and 1,6-Enynes Providing 3,3-Bis(trimethylsilyl)-3-silabicyclo[3.3.0]octanes and 3-Silabicyclo[3.3.0]oct-1-enes
Authors: Miura Katsukiyo , Oshima Koichiro , Utimoto Kiitiro 
Published: August 2006

Abstract
Treatment of 1,6-dienes with tris(trimethylsilyl)silane in the presence of Et3B or α,α′-azobis(isobutyronitrile) afforded 3,3-bis(trimethylsilyl)-3-silabicyclo[3.3.0]octanes in addition to monocyclized cyclopentanes. Bicyclization of 1,6-enynes provided the corresponding 3-silabicyclo[3.3.0]oct-1-enes.
Photosubstitution of Dicyanobenzenes by Allylic Silanes, Germanes, and Stannanes via Photoinduced Electron Transfer
Authors: Nakanishi Kazuhisa , Mizuno Kazuhiko , Otsuji Yoshio 
Published: August 2006

Abstract
Photoreactions of 1,2- and 1,4-dicyanobenzenes (o- and p-DCB) with allylic silanes, germanes, and stannanes in acetonitrile were studied under various conditions. In these photoreactions, one of cyano groups of o- and p-DCB was replaced by allylic groups. With trimethyl(3-methyl-2-butenyl)silane, -germane, and -stannane, the photosubstitution occurred at both α- and γ-positions of the allylic moiety in a constant ratio, regardless of the kinds of metals. 1,3-Dicyanobenzene (m-DCB) was less reactive to the photosubstitution reaction. The reactivity of group 14 organometallic compounds increased in the order: Si- &lt; Ge- &lt; Sn-compounds. The photoreactions were sensitized by aromatic hydrocarbons such as phenanthrene and triphenylene, and also accelerated by adding Mg (ClO4)2 and alkylbenzenes. Quantum yields for the formation of the substitution products increased with decreasing oxidation potentials of group 14 organometallic compounds. A key step for the photoreactions is the reaction of radical anions of dicyanobenzenes with allylic radicals that are generated by cleavage of radical cations of group 14 organometallic compounds. The mechanistic features of these photoreactions are discussed.
Oxidation of Alkenes with Hydrogen Peroxide Catalyzed by Iron Porphyrins Immobilized to Imidazole Groups in a Hydrophobic Environment on a Modified Silica Surface
Authors: Miki Keiji , Sato Yoshiki 
Published: August 2006

Abstract
A biomimetic model of a monooxygenase enzyme was designed and synthesized on a silica surface using a facile procedure, for the purpose of direct functionalization of hydrocarbons. Immobilization and isolation of simple and bulky forms of iron tetraphenylporphyrin was accomplished by coordinative ligation to anchored imidazolyl groups in hydrophobic cavities formed by alkyl chains attached to the surface. The synthesized catalyst was dispersed in an aqueous solution with alkenes. The substrates were catalytically epoxidized by H2O2 as the oxygen donor in the presence of imidazole. The high catalytic activity for the epoxidation of alkenes is discussed with respect to the characteristics of the novel catalyst structure and of the applied reaction system.
Highly Selective Biocatalytic Cycloaddition of Azodicarboxylates to Vinylpyridines
Authors: Kakulapati Rama Rao , Nanduri Bhanumathi , Kota Narsimha Reddy 
Published: August 2006

Abstract
Biocatalytic [4+2] cycloaddition of vinylpyridines with azodicarboxylates in the presence of ‘Saccharomyces cerevisiae’ proceeds selectively in good yields.
9H-Xanthene-2,7-diols as Antioxidant for Autoxidation of Tetralin
Authors: Nishiyama Tomihiro , Ishida Takafumi , Miyazaki Satoshi , Tsuji Ryuhei , Yamada Fukiko 
Published: August 2006

Abstract
The antioxidant activities of 9H-xanthene-2,7-diols were evaluated by means of an oxygen-absorption method at 60 °C for tetralin. Very good activities were observed for 1,3,4,5,6,8-hexamethyl-9H-xanthene-2,7-diol and 1,3,4,5,6,8,9-heptamethyl-9H-xanthene-2,7-diol.
3,3,3-Trifluoro-1-nitropropene as a Novel Trifluoromethyl-Containing Building Block
Authors: Iwata Satoru , Ishiguro Yoshiharu , Utsugi Masataka , Mitsuhashi Keiryo , Tanaka Kiyoshi 
Published: August 2006

Abstract
Additions of various carbanion nucleophiles to 3,3,3-trifluoro-1-nitropropene (1) proceeded regiospecifically at the C-2 position of 1 to give the corresponding adducts. The nitro group of the adducts, derived from the reactions with acetylacetone and ethyl acetoacetate, was reduced to the corresponding amines, which were cyclized in situ to the 3-(trifluoromethyl)pyrrole derivatives.
Enhanced Cation Transport Property of Polymeric “Armed Macrocycles”
Authors: Tsukube Hiroshi , Iwachido Tadashi , Shimotani Tatsuo , Dando Tatsuya , Zenki Michio 
Published: August 2006

Abstract
Poly(diazacrown ether)s with dihydroxyalkylene bridges exhibited enhanced transport ability for alkali metal cations via three–dimensional complexation, though poly(armed azamacrocycle)s did little.
The role of meta‐cognitions and thought control techniques in predisposition to auditory and visual hallucinations
Authors: García‐Montes José M. , Cangas Adolfo , Pérez‐Álvarez M. , Fidalgo Ángel M. , Gutiérrez Olga 
Published: August 2006

Objectives. This study examines the relationship between a predisposition to hallucinations and meta‐cognitive variables and thought‐control techniques, controlling for the possible effect of anxiety. In order to do so, we start out with the hypothesis that anxiety does not, in itself, explain the association between meta‐cognitions and a predisposition to auditory and visual hallucinations.Design. A within‐participants correlational design was employed.Methods. Four psychometric tests relating to predisposition to hallucinations, anxiety, meta‐cognitions and thought‐control techniques were administered to 150 participants.Results. It was found that, after controlling for participants' anxiety levels, the ‘loss of cognitive confidence’ factor predicted the score on the scale of predisposition to both auditory and visual hallucinations. Thought‐control strategies based on worry were also found to be predictive of a greater predisposition to hallucinations, regardless of whether or not participants' anxiety level was controlled.Conclusions. Meta‐cognitive variables of cognitive confidence and thought control through worry are positively associated with a predisposition to hallucinations.Limitations. The correlational nature of the design does not allow inferences about causal relationships.
The Beck Depression Inventory in patients undergoing opiate agonist maintenance treatment
Authors: Hesse Morten 
Published: August 2006

Background and objectives.  The Beck Depression Inventory (BDI) is a widely used measure of depression severity in both research and clinical contexts. This study aimed at assessing its stability and associations with ongoing drug use in a sample of patients in opiate agonist maintenance treatment who were not abstinent from illicit drugs.Design and method.  The study was a prospective, naturalistic study. Subjects in enhanced or standard psychosocial services along with opiate agonist maintenance treatment were administered the BDI and the European Addiction Severity Index (EuropASI) twice by research technicians, approximately 2 weeks after intake and at 18 months follow‐up.Findings.  There were rather small mean changes from intake to follow‐up in the BDI, and mean‐level stability in subjects was rather high as evidenced by a high intra‐class correlation between intake score and follow‐up score. The stability of the BDI was reduced at high levels of drug use severity at intake, and BDI was a moderate predictor of drug use severity at follow‐up.Conclusions.  The BDI measures a construct that is both stable and of predictive validity in a sample of non‐abstinent opiate agonist maintenance patients, although very severe drug use at baseline appeared to reduce the stability of the BDI.
Parental recall, attachment relating and self‐attacking/self‐reassurance: Their relationship with depression
Authors: Irons C. , Gilbert P. , Baldwin M.W. , Baccus J. R. , Palmer M. 
Published: August 2006

Objectives. When things go wrong for people they can become self‐critical or focus on positive, reassuring aspects of the self. This study explored the relationship between forms of self‐criticism and self‐reassurance, recall of parental experiences and attachment style in relation to depressed symptoms in students.Methods. A sample of 197 undergraduate students from the UK and Canada completed self‐report questionnaires measuring recall of parental styles, attachment, forms of self‐criticism, self‐reassurance, and depression symptoms.Results. Recall of parents as rejecting and overprotecting was significantly related to both inadequacy and self‐hating self‐criticism. In contrast, parental warmth was negatively correlated with these forms of self‐criticism. In addition, when things go wrong for the person, recall of parental warmth was associated with the ability to be self‐reassuring. A mediator analysis suggested that (1) the impact of recall of negative parenting on depression is mediated through the forms of self‐criticism and (2) the effect of parental warmth on depression was mediated by the ability to be self‐reassuring.Conclusions. The impacts of negative parenting styles may translate into vulnerabilities to depression via the way children (and later adults) develop their self‐to‐self relating (e.g. as self‐critical versus self‐reassuring). Hence, there is a need for further research on the link between attachment experiences, recall of parental rejection/warmth and their relationship to internal, self‐evaluative and affect systems in creating vulnerabilities to psychopathology.