bluuebunny/crossref_metadata_2025 huggingface dataset:
The Crystal and Molecular Structure of Anhydrous Zinc 8-Quinolinolate Complex, [Zn(C9H6NO)2]4
Authors: Kai Yasushi , Morita Masahiro , Yasuoka Noritake , Kasai Nobutami
Published: July 2006

The molecular structure of an anhydrous zinc 8-quinolinolate obtained by sublimation has been determined by means of X-ray diffraction. The complex forms triclinic crystals; a=11.858(1), b=13.019(2), c=10.834(1) Å, α=106.56(1), β=109.00(1), and γ=74.14(1)°, space group P\bar1 (No. 2) with one [Zn(C9H6NO)2]4 molecule. The structure was solved by the heavy atom method and refined by the block-diagonal least-squares procedure to R=0.043 for 3320 non-zero reflections. The molecule is centrosymmetric and tetrameric; four [Zn(C9H6NO)2] units being connected by oxygen atoms of 8-quinolinolate ligands. Two types of bridging oxygen atoms were found. Two crystallographically independent zinc atoms take different geometries, hexa-, and pentacoordinations.
Partial Molal Volumes and Volume Changes for the Complex Formation of Metal Chelate Electrolytes, Na2[M(edta)] and K[M(hedta)(H2O)]
Authors: Yoshitani Kouzou
Published: July 2006

The partial molal volumes, V∞, of [M(edta)]2− and [M(hedta)(H2O)]− (M=Mn(II), Co(II), Ni(II), Cu(II), and Zn(II) and H3hedta=N-(2-hydroxyethyl)ethylenediamine-N,N′,N′ -triacetic acid) and two free ligands, edta4− and hedta3−, have been determined from density measurements at 25 °C. From the results for V∞, the volume changes for the complex formation of [M(edta)]2− and [M(hedta)(H2O)]−, ΔV∞, were estimated. The values of ΔV∞, for [M(edta)]2− (32.8 to 45.8 cm3 mol−1) and for [M(hedta)(H2O)]− (25.2 to 36.5 cm3 mol−1) were large, positive ones, and a linear relationship between ΔV∞ and ΔS was observed for these metal chelate ions.
The Stereoselective Retardation of the Alkaline Hydrolysis of Organic Esters by Binuclear Cu(II) Complexes with Cyclodextrins
Authors: Matsui Yoshihisa , Suemitsu Daisuke
Published: July 2006

The alkaline hydrolysis of p-nitrophenyl acetate (p-NPA) in 1.0mol dm−3 NaOH at 25 °C was almost completely retarded by the addition of a binuclear Cu(II) complex with α-cyclodextrin (Cu2α-CD). The dissociation constant for an inclusion complex of Cu2α-CD with p-NPA was determined to be 0.059 mmol dm−3, which is about one 200th that for an inclusion complex of α-CD with p-NPA. The alkaline hydrolysis of o- and m-nitrophenyl acetates was also retarded by Cu2α-CD, though the extent of retardation was much less than that for p-NPA. A binuclear Cu(II) complex with β-cyclodextrin (Cu2β-CD) also caused a stereoselective deceleration of the alkaline hydrolysis of the esters. However, the stereoselectivity of Cu2β-CD was not so remarkable as that of Cu2α-CD. Dissociation constants for inclusion complexes of Cu2α2-CD with several alcohols and other organic substrates were determined by the kinetic examination of the competitive inhibition effect of the substrates on the association of Cu2α-CD with p-NPA. Cu2α-CD formed stable inclusion complexes with such disk-like molecules as cyclohexanol, cycloheptanol, and p-nitrobenzyl alcohol. The geometry of a Cu2α-CD-p-NPA inclusion complex was presumed on the basis of these results.
Anodic Oxidation of Cyclohexanone on Lead Dioxide Electrode in Aqueous Sulfuric Acid Solution
Authors: Kunai Atsutaka , Hatoh Kazuhito , Hirano Yoshinobu , Harada Junji , Sasaki Kazuo
Published: July 2006

The electrolytic behavior of cyclohexanone was examined by potentiometry with rotating disk electrode as well as by product analyses. The reaction was activation controlled and the reaction orders were first with respect to cyclohexanone and zero for proton. Cyclohexanone reacted by approximately 6 electrons to give adipic acid mainly which accumulated proportionally to the electricity consumed. Changes in temperature, proton concentration, and current density resulted in only minor effects on the reaction. In neutral solution, however, the oxidation was suppressed and oxygen evolution dominated. Other electrode materials such as Pt, graphite, RuO2, and PtO2 were inactive. The chemical oxidation with PbO2 itself did not occur. From these facts, reaction mechanism was discussed.
Structure–Taste Relationships of Aspartyl Tetrapeptide Esters
Authors: Ariyoshi Yasuo
Published: July 2006

A series of fourteen analogues of l-α-Asp–Gly–Gly–Gly–OMe has been synthesized in relation to structural features of sweet peptides. The rule in the structure-taste relationships of tripeptides barely applies to the aspartyl tetrapeptide esters. In order for the aspartyl tetrapeptide esters to be sweet, the second amino acid must have a d-configuration and a small, compact alkyl side chain. However, the sweetness was accompanied by a bitter or astringent taste. Moreover, some of the tetrapeptides were not sweet but bitter, though they satisfied the requirements for sweet peptides. With increasing length of a peptide, it becomes difficult to fit the deep receptor pocket.
Formation of Blocking Contacts at p-Type Porphyrin/ITO or Electrolyte Junctions
Authors: Yamashita Kazuo , Harima Yutaka , Matsumura Yuhei
Published: July 2006

Energetics of ITO/p-type porphyrin/electrolyte interfaces are discussed on the basis of photoelectrochemical and photovoltaic measurements. When sensitized by a layer of 5,10,15,20-tetraphenylporphyrinatomagnesium(II)(MgTPP), the indium-tin oxide (ITO) electrode acts as only a photocathode in an aqueous electrolyte solution. However, the ITO electrode modified with a film of ZnTPP, CuTPP or H2TPP having oxidation potential more positive than that of MgTPP acts as not only a photocathode but also a photoanode, depending on the electrode potential and the direction of irradiation on the ITO/porphyrin electrode. The cathodic component in the photocurrents is attributed to the downward band-bending in a space charge layer at the porphyrin/electrolyte (blocking) contact and the anodic component to that at the ITO/porphyrin (blocking) contact. The upward band-bending, on the contrary, is found inefficient in producing charge carriers, because the accumulation layer is conducting (ohmic) for majority carriers (holes). The porphyrin/electrolyte junction shows certain similarities to an ITO or metal/porphyrin (semiconductor) junction. However, it should be noted that a Helmholtz double layer exists at the porphyrin/electrolyte interface. The results are rationalized from the energy levels of the porphyrin films, ITO and the redox couple solutions with due regard to the orientation of water dipoles at the porphyrin surface.
Intermolecular Hydrogen Bonding of Enantiomers of Pantolactone Studied by Infrared and 1H-NMR Spectroscopy
Authors: Nakao Yoshihiko , Sugeta Hiromu , Kyogoku Yoshimasa
Published: July 2006

Intermolecular associations of the enantiomers of pantolactone in carbon tetrachloride solution have been studied by infrared and 1H-NMR spectroscopic methods. The spectroscopic data have been analyzed by the least squares method to obtain the association constants and thermodynamic parameters. It was found that pantolactone takes a cyclic dimer structure by dint of hydrogen bonding. The association constant for homochiral dimerization was obtained to be 8.9 mol−1 dm3 at 26°C and the enthalpy and entropy changes were −35 kJ mol−1 and −97 J K−1 mol−1, respectively. The association constant for heterochiral dimerization is just twice as large as that for homochiral dimerization, that is, no selective association exists between enantiomers.
Syntheses and Properties of Oxomolybdenum(VI), -(V), and -(IV) Complexes with Ferrocenecarbodithioate
Authors: Nakamoto Masami , Tanaka Koji , Tanaka Toshio
Published: July 2006

A series of ferrocenecarbodithioato–oxomolybdenum(VI), -(V), and -(IV) complexes, MoVIO2(S2CC5H4FeIIC5H5)2 (1), MoV2O3(S2CC5H4FeIIC5H5)4 (2), and MoIVO(S2CC5H4FeIIC5H5)2 (3) have been prepared. Complex 2 under-goes a disproportionation reaction in solution and exists as an equilibrium mixture with 1 and 3. Cyclic voltammograms of 1 and 3 display two and three sets of quasi-reversible couples, respectively, arising from stepwise redox reactions of the molybdenum and iron sites. Electronic spectra revealed that the oxidized species [MoVIO2(S2CC5H4FeIIIC5H5)2]2+, [MoVO(S2CC5H4FeIIC5H5)2]+, and [MoVO(S2CC5H4FeIIIC5H5)2]3+ generated electrochemically are considerably stable owing to the electron-donating ability of the ferrocenecarbodithioate ligand.
The Promotion Effect of Surface Hydroxyl on the Oxygen Adsorption over NiO, Fe2O3, and CuO
Authors: Takita Yusaku , Saito Yumie , Tashiro Tetsuro , Hori Fumiaki
Published: July 2006

Oxygen TPD revealed that the adsorption of water vapor at 278 K promoted the desorption of the preadsorbed oxygen at 793→278 K over NiO and Fe2O3. Preadsorption of water vapor at 473 K brought about a marked enhancement over Fe2O3 and a slight increase over CuO in the adsorption of oxygen at 473→278 K.
UV and Visible Fluorescences of CF3 Radicals Produced by the Two-photon Decomposition of CF3Br and Their Radiative Lifetimes
Authors: Washida Nobuaki , Horie Osamu , Becker Karl H
Published: July 2006

The UV and visible emission bands of the CF3 radical were observed in the two-photon decomposition of CF3Br using KrF excimer laser (248 nm) radiation. Very short radiative lifetimes (shorter than 40 and 50 ns for the UV and visible bands, respectively) were obtained.
Decomposition of Solid Potassium Nitrate by Incident 100 keV Ions
Authors: Furukawa Katsutoshi , Ohno Shin-ichi
Published: July 2006

Potassium nitrate was bombarded at 100 keV energy with ion beams extracted from a discharge of D2, He, N2, and O2, and the yield for the formation of nitrite ion was determined: G(NO2−)=1.8, 1.8, 0.5, and 0.5, respectively. The results suggest that the reaction takes place via electronic excitations.
A Fairly Effective Environment Substance [Co(sep)]3+ Ion in the Pfeiffer Effect of Some Oxalato Complexes of Chromium(III)
Authors: Miyoshi Katsuhiko , Sakamoto Yukio , Toda Yoshihisa , Yoneda Hayami
Published: July 2006

A chiral complex ion [Co(sep)]3+ (sep=1,3,6,8,10,13,16,19-octaazabicyclo[6.6.6]eicosane) was found to displace the chiral equilibrium between Δ and Λ enantiomers greatly for moderately optically labile metal complexes [Cr(ox)2(acac)]2− and [Cr(ox)2(gly)]2− in dioxane–water mixtures.
Rate Coefficient for H+C2H2\ightleftarrowsC2H+H2
Authors: Gardiner William , Tanzawa Tsuneo , Koike Tohru , Morinaga Kihei
Published: July 2006

The rate coefficient expressions k=1013.78 exp(−99 kJ/RT) cm3 mol−1s−1 for H+C2H2→C2H+H2 and k=1013.05 exp(−12 kJ/RT) cm3 mol−1s−1 for C2H+H2→H+C2H2 were proposed after correcting for errors in previously reported data analyses of shock tube data on C2H2 pyrolysis.
Determination of the Stability Constants of Crown Ether Complexes with Protonated Amines by Solvent Extraction
Authors: Noguchi Hideyuki , Nagamatsu Masatoshi , Yoshio Masaki
Published: July 2006

Stability constants of crown ether complexes with protonated primary amines were determined by the solvent extraction method. Stability constants between protonated amines(AH+) and 18-crown-6(L), logKAHL, were found to be 0.4, 0.15, 0.1, −0.05, and −0.1 for protonated methylamine, ethylamine, propylamine, butylamine, and iso-propylamine at 25.0°C, respectively.
Reactions of Aromatic Azido, Azo, Azoxy, and Hydrazo Compounds with Diphosphorus Tetraiodide
Authors: Suzuki Hitomi , Tani Hiroyuki , Ishida Shigeko
Published: July 2006

On treatment with diphosphorus tetraiodide in boiling benzene followed by aqueous work-up, the title nitrogen-containing compounds undergo a reductive cleavage of the nitrogen–nitrogen bond, giving the corresponding amines in low to good yields.
Regioselective Monoalkylation of Ketones with Allylic Nitro Compounds
Authors: Ono Noboru , Hamamoto Isami , Kaji Aritsune
Published: July 2006

Lithium enolates from 2-methylcyclohexanone and p-methylacetophenone react with allylic nitro compounds in the presence of triethylborane (2 equiv) and Pd(PPh3)4 (5 mol%) to give monoallylated compounds regioselectively.
The Nature of the Cosolvent Effects of Sugars on the Aqueous Solubilities of Hydrocarbons
Authors: Janado Masanobu , Yano Yuki
Published: July 2006

Pentoses (d-arabinose, d-xylose, and d-ribose) and hexoses (d-glucose, d-galactose, and d-mannose) increased appreciably the aqueous solubilities of naphthalene and biphenyl, but all the sugars except ribose caused solubility depression of 1-octanol. Ribose increased most effectively the hydrocarbon solubilities while glucose showed the least effect. Deoxy sugars and methyl glycosides were more effective than the corresponding unsubstituted sugars. As to maltodextrins the solubility-increasing effect per glucose unit is cooperatively enhanced as the number of glucose residue increases. On the basis of these data, it was concluded that the cosolvent effects of the sugars are primarily brought about by their nonpolar interactions with hydrocarbons that occur at the structure-breaking sites of the sugar molecules.
Reactions of Trimethylsilyl Cyanide with Tropone, 2-Phenyltropone, and 2-Methoxytropone. Formations of 2-Cyano-1-hydroxytropylidene Derivatives
Authors: Saito Katsuhiro , Kojima Hisashi
Published: July 2006

Reaction of trimethylsilyl cyanide (TMSCN) with tropone and 2-phenyltropone in the presence of a catalytic amount of zinc iodide in dichloromethane afforded silyl ethers of 7-cyano-1,3,5-cycloheptatriene-1-ol (2a) and 2-phenyl-7-cyano-1,3,5-cycloheptatriene-1-ol (2b), respectively. On the other hand, reaction of TMSCN with 2-methoxytropone gave 2-cyanotropone. Upon hydrolysis, 2a, and 2b yielded 2-cyano-1,3,5-cycloheptatrien-1-ol (3a) and a tautomeric mixture of 2-cyano-7-phenyl-1,3,5-cycloheptatrien-1-ol (3b) and 2-cyano-7-phenyl-3,5-cycloheptadien-1-one (4b). Oxidation of 3a and the tautomeric mixture of 3b and 4b with selenium dioxide in dioxane afforded 2-cyanotropone and 2-cyano-7-phenyltropone, respectively.
Alkylation of Ketoxime with Dichloromethane Using Bases under Phase-transfer Conditions. Formation of Methylene Dioxime and Novel Heteromacrocyclic Compounds
Authors: Hosokawa Takahiro , Ohta Toshiyuki , Okamoto Yoshihiro , Murahashi Shun-Ichi
Published: July 2006

Ketoximes, when treated with KO2 (1 equiv) in the presence of di-μ-chlorobis(2-methylallyl)dipalladium(II) (0.1 equiv per Pd) in dichloromethane, give methylene dioximes in moderate yields. This alkylation of ketoximes with CH2Cl2 is also promoted by the use of potassium carbonate in the presence of phase-transfer catalysts such as 18-crown-6. Study on the reactivity of a series of ketoximes in these reactions shows that proton abstraction by base is a crucial step in the latter reaction. By contrast, in the former system the reactivity is supposed to be controlled by nucleophilicity of the oximate anion coordinated to palladium(II). Application of the present reaction to (E,E)-1,2-diketone dioxime such as dimethylglyoxime leads to the formation of novel 21-membered ring heteromacrocyclic compounds in which oxime units are sequentially linked by methylene bridge.
Kinetics and Mechanistic Study of the Methanol Homologation with Cobalt–Ruthenium Mixed Catalyst
Authors: Watanabe Kazuhiro , Kudo Kiyoshi , Sugita Nobuyuki
Published: July 2006

The role of each catalyst was examined in detail in the methanol homologation with cobalt–ruthenium mixed catalyst. Cobalt catalyst showed much higher activity for the hydrocarbonylation of methanol than ruthenium. On the other hand, the hydrogenation of acetaldehyde proceeded much more rapidly by ruthenium catalyst. The rate of methanol homologation in 1,4-dioxane with cobalt–ruthenium mixed catalyst system was found to be of the first order with respect to the partial pressure of CO. The in situ IR spectra indicated that [Co(CO)4]− was an active species for the hydrocarbonylation of methanol and that [Rulx(CO)y] existed under the reaction conditions. On the basis of both the kinetic studies and in situ IR spectral observations, the reaction mechanism of methanol homologation was fully discussed.
Reduction Mechanism of 2,3,5-Triphenyltetrazolium Chloride and 1,3,5-Triphenylformazan
Authors: Umemoto Kisaburo
Published: July 2006

The reduction mechanism of 2,3,5-triphenyltetrazolium chloride(TTC) and 1,3,5-triphenylformazan was studied by electrochemical, ESR, and spectrophotometric methods. In non-aqueous aprotic solvent, 2,3,5-triphrnyltetrazolium ion was reduced to formazan anion either by two-electron reaction or by disproportionation reaction of tetrazolinyl radical generated by one-electron reduction of TTC. The same formazan anion was generated by one-electron reduction of 1,3,5-triphenylformazan. In the presence of proton donor, the formazan anion was converted to formazan by protonation reaction and cyclic regeneration of formazan was observed in the reduction of formazan. These results indicate that the quantitative determination of reducing materials by using TTC may possibly lead to erroneous evaluation of reductants unless the strength of electron donating property of reductants is established.
A Competition between 1,3-Dipolar Cycloaddition and Substitution of Trifluoroacetonitrile Oxide
Authors: Tanaka Kiyoshi , Masuda Hideyuki , Mitsuhashi Keiryo
Published: July 2006

Trifluoroacetonitrile oxide reacted with conjugated olefins such as styrenes, indenes, and acyclic conjugated dienes to give not only the cycloadduct but also its linear isomeric oxime. Methyl or phenyl group attached to the unsaturated carbon of the dipolarophiles was found to favor the formation of oxime. Such a concomitant reaction was interpreted in terms of a competition between a concerted cycloaddition and a two-step substitution through an electrophilic attack of nitrile oxide. Similar competitions were also investigated with cyclic conjugated dienes, where the competitive ratio of the products was found to depend on the ring size.
A Rationalization of Orientation in Nucleophilic Aromatic Photosubstitution
Authors: Mutai Kiyoshi , Nakagaki Ryoichi , Tukada Hideyuki
Published: July 2006

Consideration of the relationship between the mechanisms and orientation effects of the nitro group in nucleophilic photosubstitutions of nitroaromatics leads to the proposal of two rules, making use of frontier molecular orbital theory, for interpreting the regioselectivities and determining the reaction mechanisms. The first rule is a summary of previously proposed interpretations, concerning photoreactions accompanying the direct addition of a nucleophile to an excited nitroaromatic substrate. In this case, the regioselectivity is governed by the HOMO of the substrate. The second rule regards reactions involving photo-induced electron transfer, where regioselectivity is LUMO-controlled. The application of these rules is successfully demonstrated for various types of compounds.
Nuclephilic Photoreaction of Chlorobenzene in Methanol as Studied by Emission Spectroscopy
Authors: Nagaoka Shin-ichi , Takemura Takeshi , Baba Hiroaki
Published: July 2006

The photoreaction of chlorobenzene in methanol has been studied by means of emission spectroscopy. Upon irradiation with UV light, chlorobenzene reacts with methanol to form anisole with a quantum yield of 0.049 at 18 °C. Contrary to the case of chlorobenzene, the photoreaction of p-dichlorobenzene with methanol is not observed. By combining these results with those of our recent studies on the dual phosphorescence from low-lying triplet states of halogenated benzenes, it is suggested that the photoreaction of chlorobenzene with methanol, which is a nucleophilic substitution reaction, occurs in the 3(π,σ*) state. From the temperature dependence of the quantum yield, the activation energy for the nucleophilic photoreaction is estimated to be larger by about 3–4 kcal mol−1 than the apparent activation energy for a combination of the nonradiative 3(π,σ*)→S0 process and the homolytic dissociative process concerning the C–Cl bond in the 3(π,σ*) state. It is suggested that the nucleophilic photoreaction contrasts with the radical reaction leading to the dissociation of the C–Cl bond; the latter reaction occurs in the 3(π,π*) state as well as in the 3(π,σ*) state.
Complex Formation in Cationic Dye–Organic Anion Systems in Aqueous Solution
Authors: Hamai Sanyo
Published: July 2006

The interaction between a cationic dye, Methylene Blue (MB), and organic anions (1-naphthalenesulfonate, 2-naphthalenesulfonate, 1-naphthaleneacetate, 2-anthracenesulfonate, 2,7-naphthalenedisulfonate, and 1,3,6-naphthalenetrisulfonate) in aqueous solution has been investigated by means of absorption and fluorescence spectra. The red shifts of the absorption and fluorescence spectra of MB caused by the addition of the organic monoanion are attributed to the 1:1 complex formation between MB and the organic anion. The thermodynamic quantities as well as the equilibrium constants for the complex formation have been determined. From the finding that the absorption spectrum of MB is not affected by the addition of ethanesulfonate, it is concluded that the complex formation is due to the interaction between the MB cation and the aromatic ring in the organic anion. The addition of polyanion (e.g., 2,7-naphthalenedisulfonate) in the low-concentration range accelerates the dimerization of MB; whereas, in the high-concentration range, the formation of the 1:1 complex rather than the MB dimer is dominant. Studies on the complex formation with monoanions have also been made for Rhodamine 6G, Pyronine G, Safranin T, and Crystal Violet, and similar results to that for MB have been obtained.
Proton-induced Quenching of Methoxynaphthalenes Studied by Laser Flash Photolysis and Inclusion Effect of β-Cyclodextrin on the Quenching
Authors: Shizuka Haruo , Fukushima Masaru , Fuju Takuya , Kobayashi Takayoshi , Ohtani Hiroyuki , Hoshino Mikio
Published: July 2006

Proton-induced quenching in both excited singlet and triplet states of methoxynaphthalenes in H2O–CH3CN mixtures has been studied by means of laser flash photolysis. Inclusion effect of β-cyclodextrin (βCD) on the proton-induced quenching has been also examined. It is shown that the proton-induced quencing (the rate constant 1kq) of 1-methoxynaphthalene (1RH) occurs effectively in the excited singlet state, but not in the triplet state on the basis of the Tn←T1 absorption measurements. There is no enhancement of triplet formation via the proton-induced quenching since the 1kq value obtained by the Tn←T1 absorption measurements agrees with that obtained by fluorimetry. It was unsuccessful to observe a protonated σ-complex produced by the excited-state protonation to the naphthalene ring. The 1:1 inclusion complex between 1RH and βCD is produced with the association constant Kg (=27 mol−1 dm3 at 300K). In the presence of βCD, the 1Lb character of 1RH increases in the fluorescent state and the proton-induced quenching of 1RH markedly decreases, which may be due to inclusion and environmental effects of βCD upon the behavior in the excited state of 1RH. As for 2RH having little or no intramolecular CT character (1La), there is no proton-induced quenching.
Active and Selective Transport of Alkali Metal Ions through a Polyelectrolyte Complex Membrane Consisting of Glycol Chitosan and the Sulfate of Poly(vinyl alcohol)
Authors: Kikuchi Yasuo , Kubota Naoji
Published: July 2006

Polyelectrolyte complex (PEC) membranes consisting of glycol chitosan and the sulfate of poly(vinyl alcohol) have been prepared. The membrane of the polyelectrolyte complex under a 50% humidity prepared in a 4% hydrochloric acid solution was stable in basic and acidic solutions. The membranes of the PECs under a 90% humidity prepared at pH 1.0 were not stable in an alkaline solution. The active and selective transport of K+ and Na+ were observed in the PEC membrane prepared in a 4% hydrochloric acid solution. The transport behavior of alkali metal ions through this membrane was much affected by the hydrogen-ion concentration, which acted as a driving force. A proton-pump mechanism was suggested for the acive transport of Na+ and K+. It was also suggested that the affinity of the carrier and changes in both the chemical and physical properties of the PEC membrane with the hydrogen-ion concentration controlled the selective transport through the membrane.
Synthesis and Structure of (Nitroacetato)((7RS,14RS)-5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane)nickel(II), [Ni(na)(Me6[14]aneN4)]
Authors: Ito Haruko , Ito Tasuku
Published: July 2006

The title compound, [Ni(na)(Ma6[14]aneN4)], has been synthesized by the reaction of α-[Ni(Me6[14]aneN4)](ClO4)2 with potassium nitroacetate (K2na) in water. X-Ray analysis shows that the complex is a cis-NiO2N4 type with the tetraazamacrocycle folded, and that a dianionic nitroacetate (na2−) chelates the nickel(II) with one oxygen atom of the CO2− moiety and one oxygen atom of the NO2− moiety to form a six membered chelate ring.
The Determination of a Small Amount of Biological Constituent by the Use of Chemiluminescence. V. An Iron-dyestuff Complex as a Catalyst
Authors: Hara Tadashi , Toriyama Motohiro , Kitamura Kouichi , Imaki Masakatsu
Published: July 2006

The catalytic activity of the iron(III) α,β,γ,δ-tetraphenylporphinetrisulfonic acid complex for the chemiluminescence reaction between luminol and H2O2 has been found to decrease in the presence of protein. On the basis of this phenomenon, 2×10−5–2×10−3 g dm−3 bovine serum albumin was determined with the detection limit of 4 ng, lower than that in the previous paper.
Heteropoly Acids Supported on Acidic Ion-exchange Resin as Highly Active Solid-acid Catalysts
Authors: Baba Toshihide , Ono Yoshio , Ishimoto Tadao , Moritaka Shun-ichi , Tanooka Seiichi
Published: July 2006

Heteropoly acids supported on a macroreticular acidic ion-exchange resin shows much higher activity than those supported on activated carbon for the synthesis of methyl t-butyl ether and the esterification of acetic acid with 1-pentanol. This high activity can plausibly be attributed to the interaction of heteropoly anions with substrates which are protonated by the protons of the acidic resin.
Kinetic Studies on the Oxidation of Electrogenerated Mo(V) and Stable Monomeric Mo(V) in Sulfuric Acid Solutions
Authors: Yokoi Kunihiko , Watanabe Iwao , Ikeda Shigero
Published: July 2006

The kinetics of polarographic catalytic reduction of nitrate and perchlorate by electrogenerated transient species of Mo(V) are investigated in 0.1M sulfuric acid solution. Second-order rate constants for the catalytic reaction with nitrate and perchlorate obtained after Koutecky’s treatment are (2.1±0.4)×103 and (1.9±0.1)×102M−1 s−1, respectively. Stable Mo(V) species in sulfuric acid solution is studied by spectrophotometry. It is concluded that there exists dimer-dimer-monomer equilibria. The oxidation of the monomer with perchlorate in 14M H2SO4 obeys the second-order rate law –d[monomer]/dt=k[monomer][ClO4−], where k=(1.59±0.13)×10−1 M−1 s−1. The results indicate that electrogenerated Mo(V) in 0.1M H2SO4 is not the same species as the stable monomeric Mo(V) in 14M H2SO4.
Rate of Complex Formation of Iron(III) with Several β-Diketones in Aqueous Perchlorate Solutions Determined by Solvent Extraction Method
Authors: Inaba Kazuho , Itoh Nobuyuki , Matsuno Yumi , Sekine Tatsuya
Published: July 2006

The rate of formation of iron(III) complexes with several β-diketones (HA) in aqueous sodium perchlorate solutions has been determined by a solvent-extraction method. The rate was found to be first order with respect to the reagent, and zero to an inverse second order with respect to the hydrogen-ion. From the results, the controlling step has been determined to be the formation of the first complex in aqueous solutions. Three types of unit reactions are suggested for this; (i) Fe3++HAenol, which has an associative character; (ii) Fe(OH)2++HAenol and; (iii) Fe(OH)2++A−, both of which has a dissociative character.
The Effect of α-Tocopherol on Polymerization of Methyl Methacrylate
Authors: Enmanji Koe
Published: July 2006

Photo- and thermal polymerizations of methyl methacrylate (MMA) in the presence of α-tocopherol were investigated in air or in vacuo. α-Tocopherol at higher concentrations inhibits both the photopolymerization of MMA sensitized by benzoin ethyl ether and the thermal polymerization induced by benzoyl peroxide, but at lower concentrations is able to initiate photopolymerization of MMA under aerobic conditions. Spectral data indicate that a fraction of α-tocopherol is incorporated in the produced polymer chain.
Pyrolyse und Eigenschaften von Tris(2,3-epoxypropyl)- und Tris(2,3-epoxy-3-methylpropyl)-1,3,5-triazin-2,4,6(1H,3H,5H)-trion
Authors: Shimasaki Choichiro , Takeuchi Masanori , Tsutuguchi Junichiro , Shimizu Koichi , Yamakawa Hisato
Published: July 2006

Die Pyrolyse von Tris(2,3-epoxypropyl)-1,3,5-triazin-2,4,6(1H,3H,5H)-trion (1)[zwei Razem-Modifikationen: Typus (R,R,R)/(S,S,S) Schmp. 103–104 °C (1a); Typus (R,R,S)/(S,S,R) Schmp. 156–157 °C (1b)] und Tris(2,3-epoxy-3-methylpropyl)-1,3,5-triazin-2,4,6(1H,3H,5H)-trion (2) wurde bei thermischen Analysen untersucht. Der Spaltungsmechanismus durch Elektronenschlag von 1 und 2 wurde massenspektrometrisch untersucht. Die thermische Zersetzungsreaktion verläuft via die Bildung von 5-gliedrige Ringe (Oxazolidinon Ring) und dem Schmelzzustand. Eine kinetische Rechnung der thermischen Zersetungsreaktion auf Grund von DTA Kurven hat gezeigt, daß die Aktivierungsenergien der Zersetzungsreaktionen von 1a, 1b, und 2 jeweils 114,170, und 146 kJ mol−1 sind. Der Hauptspaltungsmechanismus fur der Zersetzung mit dem Elektronenschlag von 1 und 2 besteht aus fünf Spaltungsstilen. Der hochauflösende Massenspektrometrie bestätigte die Zusammensetzung einer großen Anzahl von Spitzen in niederauflösenden Massenstrahlenspektren. Mittels der Kernresonanzspektroskopie läßt sich auch Spinentkopplungen und Lösungsmitteleinflüsse bei 1 und 2 untersuchen.
Reactions of α-Lithiatd 4H-1-Benzothiopyran-4-one and 1,2-Dihydrocyclopenta[b][1]benzothiopyran-9(3H)-one Derivatives
Authors: Hirao Ichiro , Yamaguchi Masahiko , Terada Takashi , Hasebe Koichi
Published: July 2006

Treatment of 5- and 7-methoxy-2-methyl-4H-1-benzothiopyran-4-one with lithium diisopropylamide followed by electrophiles gave 2-substituted 4H-1-benzothiopyran-4-ones. Utilizing this reaction, 3-substituted 6- and 8-methoxy-1,2-dihydrocyclopenta[b][1]benzothiopyran-9(3H)-ones were also synthesized, and several compounds showed potential analgesic and anti-inflammatory activities.
Synthesis and Thermal Decomposition of Di-t-Butyl Peroxydicarbonate
Authors: Komai Takeshi , Matsuyama Kazuo
Published: July 2006

Di-t-butyl peroxydicarbonate(DBPD) has been synthesized in a novel route and thermally decomposed at 40–70 °C. The decomposition exhibits first-order kinetics and the values of ΔH\eweq and ΔS\eweq are 122 kJ mol−1 and 46 J K−1 mol−1, respectively. 2-Methyl-2-propanol is obtained quantitatively as a decomposition product and the rates are a little dependant on the viscosities of solvents, normal alkanes. The mechanism that involves the initial scission of the O–O bond is discussed and the values of the rates and the activation parameters of DBPD are compared with those of diacetyl peroxide and dibenzoyl peroxide.
Vacuum UV Photolyses of Some Bichromophoric Alkenes Possessing Hydroxyl or Methoxycarbonyl Group
Authors: Inoue Yoshihisa , Goan Kazuyoshi , Hakushi Tadao
Published: July 2006

The direct photolyses at 185 nm of some naturally occurring and related bichromophoric alkenes possessing hydroxyl or methoxycarbonyl group at an allylic, homoallylic, or remote position gave the geometrical isomers as the major photoproducts detectable on gas chromatography. The isomerization yield was highly sensitive to the functional group introduced and its position; allylic alkenols gave poor yields, while both functionalization at a remote position and esterification of the hydroxyl group improve the photoisomerization yield.
Reactions of Dichloride Anion Radical with Nucleosides, Nucleotides, and Polynucleotides
Authors: Takahashi Takeo , Yamauchi Kotaro , Masuda Takahiro
Published: July 2006

Rate constants for reactions of dichloride anion radical with nucleosides, nucleotides, and polynucleotides were determined in neutral aqueous solutions of potassium chloride by the conventional flash photolysis. The reactivities of these compounds toward the anion radical are in the order: bases>nucleosides>nucleotides>polynucleotides. This trend is similar to that observed with the corresponding reactions with hydroxyl radical. A comparison of the reactivities of nucleosides, nucleotides, and polynucleotides toward dichloride anion radical with those toward hydroxyl radical has revealed that the reactivities of these compounds are governed mainly by their base moiety. This trend in the reactivities is discussed in terms of steric effect.
Stereoselective Interaction of Chiral Metal Complexes in Solution as Studied by Chromatography. I. Modes of Chiral Discrimination and Optical Resolution of Anion Complexes
Authors: Miyoshi Katsuhiko , Sakamoto Yukio , Ohguni Atsuko , Yoneda Hayami
Published: July 2006

Chromatographic resolution of some anion complexes, [Co(ox)2(en)]−, C1- and C2-cis(N)-[Co(ox)(gly)2]−, [Co(ox)2(gly)]2−, and [Co(ox)2(acac)]2− (ox=oxalate ion, en=ethylenediamine, gly=glycinate ion, and acac=acetylacetonate ion), was attempted on an ion-exchange column using as chiral selectors several optically active cation complexes such as [Co(en)3]3+, [Co(sep)]3+, [Co(pn)3]3+, [Co(chxn)3]3+, [Co(acac)(en)2]2+, and [Co(gly)(en)2]2+ (sep=1,3,6,8,10,13,16,19-octaazabicyclo[6.6.6]icosane, pn=propylenediamine, and chxn=trans-1,2-cyclohexanediamine). The elution orders and degrees of optical resolution attained were interpreted on the basis that chiral discrimination is effected along either the C3 (or pseudo C3) axis or the C2 (or pseudo C2) axis of the respective complexes; the cation complex faces the anion complex with its N–H protons hydrogen-bonded to the coordinated oxygen atoms of the anion complex along the (pseudo) C3 or C2 axis. Plausible association models were proposed, which indicate that homochiral (i.e., Δ-Δ or Λ-Λ) and heterochiral (i.e., Δ-Λ or Λ-Δ) combinations are favored when the cation complex directs its C3 and C2 axes to the anion complex, respectively, regardless of which axis (C3 or C2) of the anion complex is directed to the cation complex. Most of the experimental data are consistently explained within the framework of the association models proposed.
The Prediction of Preferred Orientation Planes in X-Ray Powder Diffractometry
Authors: Takaki Yoshito , Yamaguchi Hiroshi , Nakata Kazuaki
Published: July 2006

A method for predicting possible preferred orientation planes in organic and inorganic powders of known crystal structures is presented. The usefulness of this method is demonstrated by applying it to the powders of benzamide, the α-form of 2-pyrazinecarboxamide, benzoic acid, olivine, and the high-temperature form of Li3PO4. It should be noted that the existence of preferred orientation axes found in the powders of benzoic acid and Li3PO4 can be well explained in terms of zone axes, each formed by two sets of cleavage planes.
Electronic Structures of 3,4:3′,4′-Bis(tetramethylene)-2,2′,5,5′-tetrathiafulvalene–TCNQ and 3,4:3′,4′-Bis(tetramethylene)-2,2′,5,5′-tetrathiafulvalene-1,4-Dihydro-1,4-bis(dicyanomethylene)triptycene Complex Crystals
Authors: Akhtar Shamim , Tanaka Jiro , Nakasuji Kazuhiro , Murata Ichiro
Published: July 2006

Experimental results of the polarized reflection spectra and the calculated absorption spectra of 3,4:3′,4′-bis(tetramethylene)-2,2′,5,5′-tetrathiafulvalene (OMTTF)–TCNQ and OMTTF–1,4-dihydro-1,4-bis(dicyanomethylene)triptycene(DBTCNQ) crystals are discussed by developing approximate theoretical models, based on the CT mechanism. The electronic structures conform well that, OMTTF–TCNQ is a neutral crystal whereas, OMTTF–DBTCNQ is ionic. Furthermore, the temperature dependent spin susceptibilities imply the former as diamagnetic and the latter as a regular Heisenberg antiferromagnet.
NMR Study of Molecules in Anisotropic Systems. II. 1a,2a,3e,4e,5e,6e- and 1e,2e,3e,4e,5e,6e-Hexachlorocyclohexanes Dissolved in Nematic Liquid Crystals
Authors: Fujiwara Hideaki , Shimizu Naoto , Takagi Tatsuya , Sasaki Yoshio
Published: July 2006

NMR spectra of the titled compounds (α- and β-BHC) have been measured in nematic solvents and analyzed. Vibrational corrections were important for the full interpretation of the observed direct couplings. The order parameters showed that the BHC molecules orient most preferably with their six-membered rings parallel to the optic axis of the nematic solvents. Molecular structure of α-BHC derived from the direct couplings corresponds well with those determined by the X-ray method on a crystal and calculated by the MNDO MO method. For β-BHC, however, discrepancies are found with the crystallographic structure, suggesting molecular deformations in the crystal state. Principal axes have been determined for the order matrix and compared with those for the moment of inertia. The difference between the two principal axis systems in α-BHC is interpreted as due to a steric repulsive effect between the two axial chlorine atoms and the solvent molecules.
NMR Studies of Picolyl-type Carbanions. VIII. Anions Produced by Reactions of Alkyl-substituted Pyridines with Butyllithium
Authors: Konishi Kazuyori , Matsumoto Hiroshi , Saito Katsuhiro , Takahashi Kensuke
Published: July 2006

The 1H and 13C NMR spectra have been observed for the anions, produced from methyl-, ethyl-, and isopropylpyridines, in tetrahydrofuran (THF). Two kinds of anions are formed concomitantly by lithium-proton exchange and addition of butyllithium from 2-ethyl-, 2-isopropyl-, 4-methyl-, and 4-ethylpyridines. The former reaction tends to occur at the substituent bonded to the position adjacent to nitrogen, and the latter one occurs at the position adjacent to nitrogen without substituent. In the anions formed by the exchange from 2- and 4-ethylpyridines, a specific ring proton is coupled to the α-carbon, and, further, the ortho- or meta- protons (or -carbons) in the latter anion are nonequivalent respectively at room temperature. The α-carbons in these anions are virtually sp2-hybridized.
Effect of High Surface Coverage on the Rate of Methanol Oxidation at Platinum Electrode
Authors: Matsui Hiroshi , Hisano Takeo
Published: July 2006

The rates of the methanol oxidation and the COad formation at Pt electrodes in solutions of CH3OH+0.5 mol dm−3 H2SO4 were investigated under the conditions minimizing the harmful effect of impurities. Under the particular conditions, the both rates decreased remarkably towards zero at a limiting coverage of about 0.8. Namely, the COad hindered both the formation of the COad itself and the oxidation of methanol via some unidentified intermediate other than COad. This fact was explained by assuming an aggregate with two vacant sites indispensable for the COad formation and the methanol oxidation to CO2.
Carbon-13 NMR Chemical Shift and Electronic Structure of Solid Polypeptides as Studied by Tight-binding MO Theory. Polyglycine and Poly(l-alanine)
Authors: Yamanobe Takeshi , Ando Isao , Saito Hazime , Tabeta Ryoko , Shoji Akira , Ozaki Takuo
Published: July 2006

A tight-binding MO-sum-over-state theory has been used to calculate the 13C NMR chemical shift of polyglycine having the forms I and II and that of poly(l-alanine) having the α-helix and β-sheet forms, in order to justify the origin of the conformation-dependent 13C NMR chemical shift previously determined by the cross polarization-magic angle spinning technique. The calculated results on the carbonyl, Cα and Cβ carbons were found to exhibit the conformation-dependent 13C NMR chemical shifts comparable with the experimental data.
The Solution Chemistry of Organotin Compounds. IV. Thermodynamic Parameters of the Complex Formation between MeSnCl3 and Alkyl Sulfoxides Determined from Titration Calorimetry
Authors: Fujiwara Hideaki , Sakai Fumihiko , Kawamura Akio , Shimizu Naoto , Sasaki Yoshio
Published: July 2006

Calorimetric titration data have been analyzed to determine thermodynamic parameters of the interacting system. The system studied is MeSnCl3 plus dialkyl sulfoxide in CH2Cl2 and a nonlinear least squares method is utilized to simulate the titration curve. The 1:1 and 1(acid):2(base) complexes are found to coexist in solution, and the effect of alkyl chain length on the complex formation is examined. The complex formation proceeds most favorably under the total carbon number of four, and inductive and steric effects are considered to operate in a compensating way. Entropy changes on the reactions are discussed with the aid of molecular theory of thermodynamic functions, and a new method is suggested that affords the number of solvent molecules released on the complex formation.
Photoregulated Ion-binding to Azobenzene-linked Ethylenediamines and Iminodiacetic Acids
Authors: Shinkai Seiji , Nakamura Shinichiro , Nakashima Mikio , Manabe Osamu , Iwamoto Masakazu
Published: July 2006

New photoresponsive complexones bearing two iminodiacetic acid units or ethylenediamine units at the two sides of an azobenzene through CH2 or (CH2)2 (AzoIDA(n=1,2) and AzoED(n=1,2), respectively) have been synthesized. The CH2 and (CH2)2 spacers were selected in order to examine the influence of the spacer length on the intramolecular cooperativity for the two ligands in the cis-isomers to coordinate to one metal ion. The thermal cis-to-trans isomerization of AzoIDA was efficiently suppressed by Zn(II) and Cu(II) while that of AzoED was suppressed only by Cu(II). The rate suppression supports the formation of the intramolecular chelate complexes with the metal ion. The measurements of ESR spectra of the cis-isomer·Cu(II) complexes indicated that the square-planar structure of the complexes is somewhat distorted and probably close to a lozenge. The stability constants (Ks) were determined by a displacement method. The Ks values for the cis-isomers were generally greater than those for the trans-isomers, and the Ks for n=2 series increased more clearly. In particular, the Ks for cis-AzoED(n=2)+Cu(II) was improved by 43.8 fold. The photoresponsive change in the stability constants suggests a possible application of the present system as light-driven ion pumps for heavy metal ions.
Reactivities of Stable Rotamers. XIV. Reaction of 9-[2-(Substituted Methyl)-6-methylphenyl]fluorene Rotamers with Butyllithium
Authors: Nakamura Mikio , Suzuki Yoshio , Oki Michinori
Published: July 2006

The title compounds of which substituents carry atoms with lone-pair electrons have been prepared and their rotamers isolated as stable entities at room temperature. Deprotonation rates of these rotamers with butyllithium in benzene–hexane solution show a striking difference depending upon the substituents and the rotamers. In both sp and ap series, compounds with a methoxyl group exhibit the largest rate constants, while those with a sulfur substituent show the smallest reactivity. The difference is explained in terms of coordination ability of the heteroatoms toward butyllithium and by taking advantage of the entropy effect at the transition state of lithiation. The difference in reactivities between rotamers is further striking in a sense that the reactions differ in the order; sp rotamers show the first-order kinetics while ap rotamers obey the second-order kinetics in the substrate. By assuming that the observed rates are the sum of the first-order and the second-order contributions, we estimate the minimum ratios of the first-order rate constants between sp and ap rotamers, k1sp⁄k1ap, to be >2300 in the methoxyl and dimethylamino derivatives and >240 in the methylthio derivatives.
Crystal Structure of Potassium Dithizonate
Authors: Noda Hiroshi , Engelhardt Lutz Meinhardt , Harrowfield Jack MacBean , Pakawatchai Chaveng , Patrick Jennifer Mary , White Allan Henry
Published: July 2006

The crystal structure of potassium dithizonate, K+[C6H5·NH·N·CS·N:NC6H5]−, has been determined by single crystal X-ray diffraction methods at 295 K and refined by full matrix least squares to a residual of 0.045 for 1101 independent “observed” reflections. Crystals are orthorhombic, Pbca, a=28.942(9), b=13.247(4), c=7.163(3)Å, Z=8. The structure determination is the first carried out on a salt rather than a complex of the anion. The pseudo-planar anion stacks parallel to the ab face of the cell with considerable delocalization evident; as indicated by the above formula, the remaining acidic hydrogen atom is associated with one of the nitrogen atoms.
Cyclizations of Dianions from 2-Imino-1,2-diphenylethanone to Oxazolines, Oxazocines, and Oxazonines
Authors: Mehrotra Kailash Nath , Singh Indra Sen , Roy Jalpana
Published: July 2006

The reaction of 2-imino-1,2-diphenylethanone with sodium in ether and subsequent addition of carbon disulfide or ethyl chloroformate resulted in the formation of 3,4,5-trisubstituted 4-oxazoline-2-thiones and 2-ones, respectively. 1,4-Oxazonines and 1,4-oxazocines were also synthesised from the reaction of 2-imino-1,2-diphenylethanone with sodium in THF followed by addition of dihaloalkanes.
Remarkable Isotope Effect on the Hydrogen-atom Reaction in the Photolysis of D2–H2–HI Mixtures at 4 K. A Quantum-mechanical Tunneling Effect
Authors: Miyazaki Tetsuo
Published: July 2006

The photolysis of D2–H2–HI (0.05 mol%) mixtures has been studied at 4 K by means of ESR spectroscopy. The yield of D atoms decreases sharply upon the addition of a small amount of H2, while the yield of H atoms increases. The results of the photolysis are similar to those in the radiolysis of D2–H2 mixtures at 4 K. The preferential formation of H atoms in the photolysis and radiolysis of the D2–H2 mixtures is due to the selective H-atom-abstraction reaction from H2 by D atoms by means of a quantum mechanical tunneling.
Electrochemical Reductive Acylation of 2,3-Disubstituted 1-lndenones
Authors: Takano Nobuhiro , Takeno Noboru , Morita Mutsuo , Otsuji Yoshio
Published: July 2006

The electrochemical reductive acylation of 2,3-disubstituted 1-indenones in the presence of acetic anhydride in aprotic media such as DMF, DMSO, and aceto-nitrile gave 2,3-disubstituted 1-acetoxy-1H-indenes (2) and 1,2-disubstituted 3-acetoxy-1H-indenes (3) in good yields. The ratios of 2 to 3 in the products were affected by the substituents.
Palladium-catalyzed Ketone Synthesis from Acyl Chloride and Organoaluminum Reagents
Authors: Wakamatsu Kuni , Okuda Yasuhiro , Oshima Koichiro , Nozaki Hitosi
Published: July 2006

The reaction of organoaluminum reagents with acyl chloride catalyzed by Pd(PPh3)4 in tetrahydrofuran provides ketones in fair yields.
New Crossed Aldol Reaction. Reaction of Enamines with Aldehydes Activated by Lewis Acids
Authors: Takazawa Osamu , Kogami Kunio , Hayashi Kazuo
Published: July 2006

Enamines react with aldehydes in the presence of Lewis acids such as BF3·OEt2 to give the corresponding crossed aldol products in good yields. Reaction of dienamines with aldehydes gives the corresponding β,γ-unsaturated α-(1-hydroxyalkyl) carbonyl compounds.
Rates of Thermal Decomposition of t-Butyl Peroxypivalate
Authors: Komai Takeshi , Ishigaki Hideyo , Matsuyama Kazuo
Published: July 2006

The kinetics of decomposition of t-butyl peroxypivalate in benzene, hexane and mineral spirits were determined iodometrically in the temperature range 50–75°. The decomposition in benzene indicated smaller rate constants and activation parameters than those in hexane or mineral spirits. The solvated transition state in aromatic solvent is discussed on the basis of these results and the previously published data.
Charge-transfer Complexes of 11,11,12,12-Tetracyanoanthraquinodimethans with Various Donors
Authors: Mukai Toshio , Suzuki Takanori , Yamashita Yoshiro
Published: July 2006

Titled compounds were found to form charge-transfer (CT) complexes with aromatic hydrocarbons or tetrathiafulvalene (TTF) and the molecular complexes could be isolated.
Structures of Two New Halochamigrene Derivatives from the Red Alga Laurencia nipponica Yamada
Authors: Suzuki Minoru , Segawa Makoto , Suzuki Teruaki , Kurosawa Etsuro
Published: July 2006

The structures of two new halochamigrene derivatives isolated from the title alga were determined by chemical and spectral methods.