bluuebunny/crossref_metadata_2025 huggingface dataset:
Radiationless Transition between Randomly Fluctuating Levels. S1-T2-T1 Intersystem Crossing in Condensed Phase
Authors: Kanamaru Nobuaki
Published: July 2006

Radiationless transitions in aromatic molecules in condensed phase are examined for the case where sparse intermediate levels are involved. Effects of surrounding mediums on radiationless transitions are also discussed in which the random fluctuation of the vibrational manifolds in the solvent cages is shown to be important to meet the resonance conditions in the transitions. The theory is applied to explain the “unusually” fast S1-T2-T1 intersystem crossing in the system such as anthracene derivatives.
Substituent Effect on a Photo-Smiles Rearrangement by Laser Photolysis
Authors: Yokoyama Kenji , Nakamura Junko , Mutai Kiyoshi , Nagakura Saburo
Published: July 2006

The photo-Smiles rearrangement was studied for two homologues of N-[2-(4-nitrophenoxy)ethyl]aniline by laser photolysis, an importance being attached to the effect of the alkoxyl substituent on the reactive position. The nitro group enhances the substitution at the para position, but the alkoxyl group does not play a significant role in the photosubstitution of the molecules.
Extraction of Titanium(IV)–Pyrocatechol Violet Complex with Tridodecylethylammonium Bromide
Authors: Shijo Yoshio , Shimizu Tokuo , Sakai Kaoru
Published: July 2006

The extraction equilibria and the fundamental conditions for extracting the titanium(IV)–Pyrocatechol Volet complex anion in a form of an ionic associate with tridodecylethylammonium bromide into carbon tetrachloride is described. The absorption maxima of the extracted complex occurs at 586 nm, the molar absorptivity and the distribution ratio being 5.17×104 dm3 mol−1 cm−1 and 2.82×102. The optimum pH range for the extraction is 5.1–6.4. The composition of the complex is estimated to be Ti(PV)2(R3R′N)2. The extraction constant would be:

K ex=\frac[Ti(PV)2(R3R′N)2]0[Ti(PV)22−][R3R′N+]2,

logKex obtained is 13.5. The interference of foreign ions is discussed.
Effects of N-Methylated Diamine on Ion Pair Formation of Bis(2,4-pentanedionato)(diamine) Cobalt(III) Bromides in Nitrobenzene by Conductometry
Authors: Ito Kazuaki , Iwamoto Etsuro , Yamamoto Yuroku
Published: July 2006

The conductometric study of bis(2,4-pentanedionato)(diamine) cobalt(III) bromides in nitrobenzene at 25 °C indicated that the ion association constant of the chelate salts increases in the order, [Co(acac)2(N,N,N′,N′-tmen)]Br<Bu4NBr<[Co(acac)2(N,N-dmen)]Br<[Co(acac)2(en)]Br<[Co(acac)2(N,N′-dmen)]Br (acac=2,4-pentanedione anion, diamine: en=ethylenediamine, N,N-dmen= N,N-dimethylethylenediamine, N,N′-dmen=N,N′-dimethylethylenediamine, N,N,N′,N′-tmen=N,N,N′,N′-tetramethylethylenediamine). The results were discussed from the view points of hydrogen bonds through the N–H protons of the chelate cations to the bromide anion and cation-solvent interactions.
Synthesis of 3-Acylfurans Using 3-(Phenylthio)propanal Dimethyl Acetal as a New Synthon. Syntheses of Ipomeanine and Isoegomaketone
Authors: Watanabe Eiji , Imai Naohiro , Inomata Katsuhiko , Kinoshita Hideki , Kotake Hiroshi
Published: July 2006

It was found that 3-(phenylthio)propanal dimethyl acetal is a very useful starting material for the preparation of 3-acylfuranoterpenes. Syntheses of two naturally-occurring furans, isoegomaketone and ipomeanine were described.
Total Synthesis of a Macrocyclic Lactone Antibiotic A26771B and Its Isomers Using Carbohydrates
Authors: Tatsuta Kuniaki , Amemiya Yoshiya , Kanemura Yoshinobu , Kinoshita Mitsuhiro
Published: July 2006

Total synthesis and antibacterial activities of a macrocyclic lactone antibiotic A26771B (1) and all its isomers (2, 3, and 4) are discussed. The starting 8,9,10,12-tetra-O-benzyl-2,3,4,5,11-pentadeoxy-aldehydo-d-xylo-(E)-6-dcdecenose derived from d-glucose reacted with racemic Wittig reagent, (3-hydroxybutyl)triphenylphosphonium iodide to give 1,3,4,5-tetra-O-benzyl-2,8,9,10,11,14,16-heptadeoxy-Dl-glycero-l-xylo-hexadeca-6,12-dienitol, which was in turn converted into methyl 15-O-acetyl-6,7,8,9,10,11,12,13,14,16 -decadeoxy-4,5-O-isopropylidene-Dl-glycero-l-threo-(E)-2-hexadecenonate (13) through effective oxidation and β-elimination. Saponification followed by Yamaguchi’s lactonization of 13 afforded two diastereomeric 16-membered-ring lactones which were converted into (5S, 15R)-A26771B (1) and its (5S, 15S-diastereomer (2) by successive deacetonation, selective succinylation and oxidation. The other starting 2,3,4,6-tetra-O-benzyl-5-deoxy-aldehydo-d-lyxo-hexose, which was prepared from 2-deoxy-d-glucose, reacted with a Wittig reagent to give 8,9,10,12-tetra-O-benzyl-2,3,4,5,11-pentadeoxy-aldehydo-d-lyxo-6-dodecenose (20) followed by hydrol ysis. Similar reaction sequence from 20 with the aforesaid series for 1 and 2 afforded the (5R, 15R)-isomer (3) and (5R, 15S)-isomer (4).
Acetolysis of [4.2.2]Propellan-7-ylmethyl Tosylates
Authors: Tobe Yoshito , Yonezawa Tetsuo , Kakiuchi Kiyomi , Odaira Yoshinobu
Published: July 2006

The acetolysis rates and products of [4.2.2]propellan-7-ylmethyl tosylates were determined in order to clarify the effect of the central and external cyclobutane bonds on the modes of the ring expansion of the cyclobutylmethyl moiety. Since the products obtained from the endo tosylate were the olefin and the acetate having 1,7-tetramethylenenorbornane skeleton, it is deduced that the ring expansion occurs selectively to afford [4.3.2]propellan-7-yl cation which is stabilized by the external cyclobutane bond. In contrast, the exo tosylate gave the products derived from both [4.3.2]propellan-7-yl and -8-yl cations which are subject to the participation of the external and central cyclobutane bonds, respectively.
A Voltammetric Study of the Reduction of Ruthenium(II) Complexes with Mixed Ligands
Authors: Watanabe Junya , Saji Tetsuo , Aoyagui Shigeru
Published: July 2006

Each cyclic voltammogram for the reduction of [Ru(bpm)3]2+ (bpm=2,2′-bipyrimidine) and [Ru(bpm)L2]2+ (L=2,2′-bipyridine and dimethyl derivatives) exhibits three reversible one-electron steps. The relation between the half-wave potentials of the complexes and those of ligands suggests that the lowest redox orbital of [Ru(bpm)L2]2+ should be localized on a single bpm molecule.
Pyrolytic Sulfurization Gas Chromatography. X. The Reduction of the Analysis Time by Means of High-frequency Heating
Authors: Hara Tadashi , Okui Fujio
Published: July 2006

With the objective of reducing the analysis time in the previous PSGC method, a high-frequency induction furnace was used instead of an electric furnace. By using the present furnace, the time necessary for the pyrolytic sulfurization was reduced from 40 min to 1 min with satisfactory results.
Glass Formation in the HI + Water System
Authors: Akama Yoshifumi , Kanno Hitoshi
Published: July 2006

Glass transition temperature (Tg) of aqueous HI solution was measured as a function of HI concentration. The Tg data of aqueous HI solution suggest an anomalously low Tg value for glassy bulk pure water. Double-glasstransition phenomenon is observed at the water-rich edge of glass-forming composition range.
Dysprosium and Holmium Complexes of N(2-Pyridyl)salicylideneamine
Authors: Singh Megh , Gharia K Singh
Published: July 2006

Dysprosium and holmium isopropoxides react with monofunctional bidentate Schiff base, N-(2-pyridyl)salicylideneamine, in 1:1, 1:2, and 1:3 molar ratios in benzene to yield complexes of the types Ln(OPri)2(sap), Ln(OPri)(sap)2, and Ln(sap)3 (where Ln=Dy or Ho and sap− is the anion of the Schiff base sapH). Probable structures for these complexes are proposed on the basis of molecular weight and IR spectroscopic data. Reports on metal complexes derived from Schiff bases have aroused considerable interest in the field of coordination chemistry, and have been extensively studied. A literature survey reveals that no work has been done on Dy(III) and Ho(III) complexes of heterocyclic Schiff base, N-(2-pyridyl)salicylideneamine. However, complexes of this Schiff base with d-transition elements have been reported. The present paper deals with the synthesis of Dy(III) and Ho(III) complexes of N-(2-pyridyl)salicylideneamine and their characterization by infrared spectra.
Time-resolved Emission Spectra of 2-Acetylanthracene/Methanol/Hexane System. Evidence for the Photoassociation of a 1:2 Hydrogen Bonded Complex
Authors: Tamaki Takashi
Published: July 2006

The deconvolved time-resolved emission spectra of 2-acetylanthracene in hexane containing 0.1 mol dm−3 of methanol revealed a considerable time-dependent spectral shift associated with the photoassociation of the hydrogen-bonded complex which includes two methanol molecules.
Effect of Temperature and Solvent on the 1,3-Dipolar Cycloaddition of Diazodiphenylmethane with Several Dipolarophiles
Authors: Yoshimura Yosuke , Osugi Jiro , Nakahara Masaru
Published: July 2006

The title reaction is studied with a series of CN- or COOCH3-substituted dipolarophiles. All the reactions obey the second-order rate law. The activation enthalpies and entropies are 44–52 kJ mol−1 and −(129–166) J K−1 mol−1, respectively. The rate constants are insensitive to solvent. The reactivity and product of dimethyl maleate are anomalous.
The Reaction of 2-Benzylidenetetralin-1-thione S-oxide with Acrylonitrile or Styrene
Authors: Ohmura Haruo , Karakasa Takayuki , Satsumabayashi Sadayoshi , Motoki Shinichi
Published: July 2006

The cycloaddition reaction of 2-benzylidenetetralin-1-thione S-oxide with acrylonitrile (or styrene) gave a mixture of 2- and 3-cyano(or phenyl)-4-phenyl-3,4,5,6-tetrahydro-2H-naphtho[1,2-b]thiopyran S-oxide. Pummerer reaction of these S-oxides resulted to afford the corresponding acetates.
Chemical Reaction Following Electroreduction of Benzophenones. 2. Relationship between the Rate Constant of Disproportionation and Spin Density
Authors: Egashira Naoyoshi , Takita Yusaku , Hori Fumiaki
Published: July 2006

Electroreduction of benzophenones in DMF in the presence of Li+ was investigated by cyclic voltammetry. Most of these radical anions underwent disproportionation reactions. The relationship between the logarithm of the rate constant of the reaction and the spin density of the carbon atom at the carbonyl group was found to be linear.
Redox Reaction of the Central Metal Ions Coordinated to Tetra(p-sulfophenyl)porphine (TPPS). II. Photoreduction of [Fe(III)TPPS]2O by Ethanol
Authors: Hatano Keiichiro , Ishida Yoshitaka
Published: July 2006

Iron(III) ion coordinated to TPPS was reduced to the divalent ion by ethanol on illumination of light. The reaction rates appear to obey the half-order kinetic of the metalloporphyrin in the buffered solutions of pH 7 to 11. A possible reaction mechanism is discussed.
α-Pentafluoropropionylation of Ketones and Aldehydes Using Hexafluoropropene Oxide. A Facile Synthesis of Fluorinated 1,3-Diketones
Authors: Ishihara Takashi , Seki Toshio , Ando Teiichi
Published: July 2006

Hexafluoropropene oxide reacts smoothly with morpholine enamines from ketones and aldehydes at 0 °C to room temperature in anhydrous THF to give pentafluorinated 1,3-diketones in good yields. The keto-enol equilibrium in the products is generally in favor of their enol form.
Electrooxidative Conversion of Aldehydes into Methyl Carboxylates
Authors: Chiba Toshiro , Okimoto Mitsuhiro , Nagai Hiroshi , Takata Yoshiyuki
Published: July 2006

The electrolytic oxidation of methanolic solutions of aldehydes in the presence of sodium cyanide at a platinum anode was found to produce corresponding methyl carboxylates.
Resonance Raman Spectra and Inter-radical Vibrations of Chloranil Anion Radical Dimers
Authors: Matsuzaki Susumu , Mitsuishi Tetsuya , Toyoda Koichi
Published: July 2006

Resonance Raman spectra of chloranil anion radical dimers were measured in ethanol at 140 K by an exciting radiation within the CT band, and all the Raman lines observed were shown to be totally symmetric. Two strong Raman lines at 114 cm−1 and 168 cm−1 have been assigned to inter-radical stretching vibrations of the dimer. The relative intensity of these lines changed depending on the counter ion species. Formation of two dimers has been supposed to explain the spectral behavior. Influence of 18-crown-6 on the spectra was investigated. The result strongly suggests that one dimer gives two inter-radical Raman lines. Two interpretations are proposed for the simultaneous resonance enhancement of these Raman lines: mechanical coupling of the inter- and intra-radical vibrations or distorsion of the D2h eclipsed dimer structure. Other five lines at higher frequencies have been assigned to intra-radical vibrations of the dimer.
The Reactions of the 1,2-Ethanediylbis(trithiocarbonic acid) Dianion with Several Electrophilic Reagents
Authors: Tanimoto Shigeo , Oida Tatsuo , Kokubo Toshio , Okano Masaya
Published: July 2006

It has been found that the reaction of the 1,2-ethanediylbis(trithiocarbonic acid) dianion with haloacetic esters, chloromethyl ethers, and chlororhethyl sulfides in tetrahydrofuran proceeds smoothly to afford 1,2-ethanediylbis(alkoxycarbonylmethyl trithiocarbonates), 1,2-ethanediylbis(alkoxymethyl trithiocarbonates) and bis(alkylthiomethyl) trithiocarbonates plus ethylene trithiocarbonate respectively.
Further Studies of Electroluminescence Spectra of the n-GaP Semiconductor Electrode in Relation with the Surface-trapped Holes
Authors: Nakato Yoshihiro , Tsumura Akira , Tsubomura Hiroshi
Published: July 2006

Electroluminescence spectra of an n-type gallium phosphide (n-GaP) electrode caused in the presence of oxidants such as [Fe(CN)6]3− and S2O82− were measured as functions of the electrode potential, the solution pH, and the kind of crystal faces. The electroluminescence spectra consisted of two bands; one was assigned to arise from electronic transitions in the bulk and the other from those at the surface. It was found that the position and the spectral shape of the luminescence band arising from the surface were quite independent of various experimental conditions, while its intensity was strongly dependent on them. These results were explained well by the view that the luminescence band is caused by “surface-trapped holes” acting as a precursor of anodic dissolution reaction of the electrode, as proposed previously. The physicochemical model of the surface-trapped hole was discussed on the basis of the above results.
The Crystal and Molecular Structure of 7,8-Epoxyhalochamigrene
Authors: Furusaki Akio , Katayama Chuji , Matsumoto Takeshi , Suzuki Minoru , Suzuki Teruaki , Kikuchi Hajime , Kurosawa Etsuro
Published: July 2006

The molecular structure of 7,8-epoxyhalochamigrene, C15H23OBr2Cl, has been confirmed by means of X-ray crystallographic analysis. The crystals are orthorhombic, with sixteen molecules in a unit cell with dimensions of a=10.303, b=71.31, and c=9.061 Å; the space group is P212121. 4241 independent intensity data were collected on a four-circle diffractometer with graphite-monochromated Cu Kα radiation. The structure was solved by the Monte Carlo direct method, using 20 reflections as a starting set, and was refined by the block-diagonal least-squares method. The final R value was 0.072. The molecular structure thus obtained corresponds to that proposed by Howard and Fenical on the basis of chemical and spectroscopic evidence. The four crystallographically-independent molecules have almost the same geometries. Of the two spiro-linked six-membered rings, the one having the epoxy group takes a half-chair conformation, while the other adopts a chair conformation. The crystal consists of alternating single and triple molecular layers parallel to the (010) plane; the latter layer has a molecular arrangement approximately of P212121 symmetry.
The Solvent Extraction of Silver and Thallium(I) Picrates by Crown Ethers
Authors: Takeda Yasuyuki , Nemoto Masashi , Fujiwara Shizuo
Published: July 2006

Extraction constants of silver and thallium(I) picrates and those of 12-crown-4 (12C4) and benzo-15-crown-5(B15C5) with silver and thallium(I) picrates have been determined between benzene and water at 25 °C. Ionpair complex-formation constants (KMLA,o) of 12C4 and B15C5 with silver and thallium picrates in the benzene solution have been calculated and compared with those of 15-crown-5 (15C5), 18-crown-6 (18C6), dibenzo-18-crown-6 (DB18C6), and dibenzo-24-crown-8 (DB24C8). The KMLA,o sequences of the crown ethers with Ag+ and Tl+ are 15C5, 18C6>DB18C6>B15C5>DB24C8>>12C4 and 18C6>>DB18C6>DB24C8>15C5>B15C5>>12C4, respectively. For both Ag+ and Tl+ systems, the relative sizes of the cation and the crown ether cavity, the number of donor oxygen atoms in the crown ether ring, the basicity of donor oxygen atom, and the flexibility of the crown ether are important factors in determining stabilities of the complexes with these crown ethers in the benzene solution.
Cyclization of Isomeric 2-Hydrazino-4-methylbenzo[h]quinoline and 3-Hydrazino-1-methylbenzo[f]quinoline. A Reinterpretation
Authors: Kocevar Marjan , Polanc Slovenko , Stanovnik Branko , Škerjanc Franc , Tišler Miha
Published: July 2006

Cyclization of 2-hydrazino-4-methylbenzo[h]quinoline and 3-hydrazino-1-methylbenzo[f]quinoline with formic acid occurs on nitrogen rather than carbon to give 5-methylbenzo[h][1,2,4]triazolo[4,3-a]quinoline and 11-methylbenzo[f][1,2,4]triazolo[4,3-a]quinoline and not 7-methyl-10H-benzo[h]pyrazolo[3,4-b]quinoline and 11-methyl-8H-benzo[f]pyrazolo[3,4-b]quinoline, respectively, as it has been claimed before.
Solvent Extraction of Alkali Metal Picrates with Poly- and Bis(benzo-12-crown-4)s
Authors: Maeda Takumi , Kimura Keiichi , Shono Toshiyuki
Published: July 2006

Solvent extractions of alkali metal picrates were carried out using newly synthesized poly- and bis(crown ether)s containing benzo-12-crown-4 moieties in a water-chloroform system. The extraction equilibrium constants(Ke) and the complexation constants (Kc) in the chloroform phase were determined at 25 °C. The Ke values for the alkali metal cations decreases as follows: Na+>K+>Rb+≥Cs+ with the poly(benzo-12-crown-4) and K+, Rb+, Cs+>Na+ with the bis(benzo-12-crown-4). The poly(benzo-12-crown-4) improved the sodium-ion selectivity of the corresponding monocyclic analog because of the easy formation of 2:1 crown ether unit-cation complexes assisted by the cooperative action of two adjacent crown ether units, while the bis(benzo-12-crown-4) did not. A separate extraction experiment was also undertaken in a water-dichloromethane system in order to compare the extractability of these benzo-12-crown-4 derivatives with that of 12-crown-4.
The Spectrofluorometric Determination of 9,10-Phenanthrenequinone
Authors: Tachibana Masaki , Hayakawa Makoto , Furusawa Motohisa
Published: July 2006

9,10-Phenanthrenequinone (9,10-PQ) reacts with guanidine in an alkaline medium to form 2-amino-1H-phenanthro[9,10-d]imidazole. The reaction can be used for the fluorometric determination of 9,10-PQ, since the reaction product is fluorescent in an acidic solution. A dimethyl sulfoxide-methanol mixture is suitable as the solvent. A sample solution was allowed to stand for 15 min at room temperature after the additions of guanidine hydrochloride and sodium methoxide solutions, followed by the addition of hydrochloric acid. After the solution had been allowed to stand for 20 min, the fluorescence intensity of the solution was measured at 403 nm with excitation at 363 nm. The fluorescence intensity was stable for at least 8 h. The determination limit of 9,10-PQ was 50 ng.
The Stereochemistry of the Photochemical Rearrangement of 1-Substituted 1a,7b-Dihydro-1H-cyclopropa[a]naphthalenes under Sensitized Conditions
Authors: Kato Masahiko , Kobayashi Hisako , Yamamoto Hiroyuki , Seto Koji , Ito Satoru , Miwa Toshio
Published: July 2006

The photolysis of 1-substituted 1a,7b-dihydro-1H-cyclopropa[a] naphthalenes in the presence of Michler’s ketone leads principally to 5-substituted 5H-benzocycloheptenes as primary products via a stepwise mechanism. The reaction proceeds smoothly with inversion of the migrating carbon if there is no steric hindrance, but it proceeds predominantly with retention if the inversion course is severely suppressed by steric hindrance. The marked difference in the exo-endo ratio of the secondary photocyclization products depending on the irradiation conditions was also recognized for 1-methoxycarbonylmethyl derivative.
Formation of Intramolecular Hydrogen Bond in Hydroxy-substituted Nitroxide Radicals as Evidenced by Electron Spin Resonance
Authors: Kotake Yashige , Kuwata Keiji
Published: July 2006

The nature of the intramolecular hydrogen bond in hydroxysubstituted nitroxide radicals was examined. The hydroxysubstituted radical was produced by the spin trapping reaction of hydroxyalkyl radicals with α-phenyl-N-t-butylnitrone. The magnitude of the hyperfine splitting caused by β-hydrogen of the radical is strongly dependent on the composition of the solvent, which is attributed to the formation of the intramolecular hydrogen bond. The equilibrium constant of the intramolecular hydrogen bond in an aprotic solvent was determined by observing the magnitude of the hyperfine splitting of β-hydrogen as a function of the amount of added methanol. Based on the temperature dependence of the equilibrium constant, the standard entropy and the standard enthalpy of the formation of the hydrogen-bonded chelate ring was estimated. The same method of analysis was applied to the system of diastereomeric nitroxide and the difference of the internal energy of the chelate ring in the isomers was detected. Moreover, the difference was utilized to separate the ESR spectra of the diastereomers.
Synthesis, Electrical Resistivities, and Electronic Reflection Spectra of Alkaline-earth Metal Cation–TCNQ–Crown Ether Complexes
Authors: Matsumoto Tsuruyoshi , Nogami Takashi , Tanaka Hidekazu , Mikawa Hiroshi
Published: July 2006

Two types of alkaline-earth metal cation–TCNQ–crown ether complexes were synthesized: one is the simple salt, expressed as [M2+(TCNQ−)2]m(crown ether)n and the other is the complex salt expressed as [M2+(TCNQ−)2]m(TCNQ)n(crown ether)i. The electrical resistivities of the complexes were measured for compacted samples and single crystals. The resistivities of the simple salts were greater than 105 Ω cm, so they are much less conductive than the original TCNQ salts, M2+(TCNQ−)2. Most of the complex salts were more conductive than the original TCNQ salts, with the resistivities of 4–103 Ω cm.
Conformational Characteristics of Poly(vinylnaphthalene)s from Energy Contour Map
Authors: Seki Kazuhiko , Imamura Yoshio
Published: July 2006

In poly(1-vinylnaphthalene)(P1VN) and poly(2-vinylnaphthalene)(P2VN), conformational energies of meso and racemic dyads were computed as functions of skeletal bond and side group rotations (0°(o) or 180°(π)). The calculation was carried out according to the truncation procedure proposed by D.Y.Yoon. The backbones in P1VN and P2VN were limited to just two rotational states, trans (t) and gauche (g) conformation. The steric interactions involving the bulky naphthyl group precluded \barg conformation; a similar situation occurs in polystyrene. Numerical results suggested these conclusions: the excimer forming site conformations for P1VN were meso : tt(ππ) and racemic : tt(ππ) states, and for P2VN were meso : tt(ππ), tt(oo), tt(oπ), and tt(πo) states. These conformations could also be correlated to the dual emissions observed in P1VN and P2VN.
Kinetic Isotope Effects in the H+C3H6→C3H7 Reaction
Authors: Watanabe Toshifumi , Kyogoku Takeshi , Tsunashima Shigeru , Sato Shin , Nagase Shigeru
Published: July 2006

The absolute rate constants of the addition of H and D atoms to propylene-d0 and -d6 have been measured by means of the pulse radiolysis-resonance absorption technique over the temperature range of 200–500 K. The rate constants obtained were well expressed by these Arrhenius equations: k(H+C3H6)=(3.00±0.38)exp[−(1612±66)⁄RT], k(H+C3D6)=(2.55±0.57)exp[−(1509±128)⁄RT], k(D+C3H6)=(1.99±0.05)exp[−(1550±15)⁄RT], and k(D+C3D6)=(2.20±0.27)exp[−(1587±67)⁄RT] in units of 10−11 cm3 molecule−1 s−1. The unit of activation energy is cal mol−1. Practically no isotope effects attributable to the difference between C3H6 and C3D6 could be observed. This is similar to the kinetic isotope effects previously observed in the rate constants of the addition of H and D atoms to isotopic ethylenes. The theoretical rate constants of the above reactions have been calculated by the conventional activated complex theory using the potential energy surface drawn by the ab initio method; however, no agreement with regard to the isotope effects could be obtained between experiment and theory because of the difference between C3H6 and C3D6. This also is similar to the isotope effects found in the H+C2H4→C2H5 reaction.
Studies on Mixed Chelates. XIII. Formation and Electronic Spectra of 5-Coordinated Mixed Copper(II) Chelates Containing N-Alkylated Ethylenediamine, Acetylacetonate, and Halide Anions
Authors: Fukuda Yutaka , Kimura Hiroko , Sone Kozo
Published: July 2006

The visible absorption spectra of three new mixed chelates of copper(II), Cu(acac)(tmen)X (acac=acetylacetonate ion, tmen=N,N,N′,N′-tetramethylethylenediamine, and X−=Cl−, Br−, or I−) were studied in various organic solvents. The \ ildeνmax values of their d-d bands depend strongly on the nature of the solvent, similarly to the pseudohalide complexes reported in the preceding paper. These data show the existence of the equilibrium:

[Cu(acac)(tmen)X]\ightleftharpoons[Cu(acac)(tmen)]++X−

 (5-coordinated) (4-coordinated, with axial solvation)

in such solutions, which is shifted to the right hand side with increase of the solvent polarity and with decrease of the coordination ability of the X− anion, i.e., in the order Cl−→Br−→I−.
The Mechanism of the Hydrolysis of Polyphosphates. VI. The Effect of Cations on the Hydrolysis of cyclo-Tri-and cyclo-Tetraphosphates
Authors: Watanabe Makoto
Published: July 2006

The effect of cations on the rate of the hydrolysis of cyclo-tri- and cyclo-tetraphosphates was studied by adding metal chlorides to aqueous solutions of the ring phosphates. The concentrations of the phosphates and metal chlorides were 0.025 mol dm−3 and 0.1 mol dm−3 respectively. Alkali-metal cations retarded the hydrolysis of both the cyclo-phosphates in acidic media and accelerated it in basic media. The following sequence of efficiency resulted:

Li+>Na+>K+.

Magnesium, calcium, and nickel(II) cations retarded the hydrolysis of the cyclo-phosphates in the pH range of 1.0–2.0 or 1.0–2.7, while they accelerated it in the pH regions higher than 2.7 or 3.5. A copper(II) ion retarded the hydrolysis at pH 1.0, and accelerated it in the pH ranges higher than 2.0. An aluminium ion highly accelerated the hydrolysis of both the ring phosphates at pH 1.0 and 2.0.
Kinetics of the Ligand Substitution Reactions of Tetrahedral Complexes [Co(NN)(hmpa)2]2+(NN=2,2′-Bipyridine, 4,4′-Dimethyl-2,2′-bipyridine, or 1,10-Phenanthroline) in Hexamethylphosphoric Triamide, Nitrobenzene, Acetone, 1,2-Dichloroethane, and Nitromethane
Authors: Abe Yuriko , Wada Goro
Published: July 2006

The substitution reaction rates of hexamethylphosphoric triamide (HMPA) for NN (NN=2,2′-bipyridine (bpy), 4,4′-dimethyl-2,2′-bipyridine (dmbpy), or 1,10-phenanthroline (phen)) on tetrahedral complexes [Co(NN)(hmpa)2]2+ were determined spectrophotometrically in pure HMPA or in nitrobenzene, acetone, 1,2-dichloroethane, and nitromethane at various concentrations of HMPA, for the purpose of clarifying the reaction mechanism and the effect of the bulkiness of HMPA. The ligand substitution reaction on bpy and dmbpy complexes proceeds simply via a dissociative mechanism in nitrobenzene. In inert solvents other than nitrobenzene, it proceeds in parallel via two simultaneous paths of both dissociative and associative mechanisms. In the case of the phen complex, the reaction proceeds only by a dissociative mechanism in pure HMPA and in all the inert solvents used. The activation enthalpies and the activation entropies of the dissociative mechanism of bpy and dmbpy complexes were (80–90) kJ mol−1 and approximately zero J K−1 mol−1, respectively, in all the solvents used. Those for the phen complex were (86–101) kJ mol−1 and (−16–+36) J K−1 mol−1, respectively, while those of the associative mechanism for bpy and dmbpy complexes in all the solvents used except nitrobenzene were (50–65) kJ mol−1 and large negative values, respectively. Whether the substitution proceeds by the dissociative mechanism or by the associative one, both the steric and the solvent effects appear seriously, because HMPA is a bulky ligand and had a large dipole moment.
Pyrolytic Sulfurization Gas Chromatography. XIII. Simultaneous Determination of the Atomic Ratio between C, H, O, and N in a Metal Organic Chelate Compound
Authors: Hara Tadashi , Fujinaga Kaoru , Okui Fujio
Published: July 2006

In order to clarify the effect of the coexistent elements on the determination of the atomic ratio between C, H, O, and N by the pyrolytic sulfurization gas chromatography (PSGC), compounds containing 25 kinds of elements were investigated. Only 7 of these interfered the determination of the atomic ratio. Several organophosphorus, lithium-, and boron-containing compounds were also analyzed. The results obtained by the present work are summarized in the periodic table together with those from previous work.
Multiple Conformations and Conformational Change in the Acetonitrile of Cation-binding Cyclic Tetrapeptide, Cyclo[Gly–l-Cys(Bzl(OMe))–Sar–l-Pro]
Authors: Shimizu Toshimi , Tanaka Yoshio , Tsuda Keishiro
Published: July 2006

The conformations of the cyclic tetrapeptide, cyclo[Gly–l-Cys(Bzl(OMe))–Sar–l-Pro] (CGCSP), in solution, were studied by means of 1H-, 13C-nuclear magnetic resonance (NMR), and circular dichroism (CD). The CGCSP equilibrates among three conformers, M, m, and n, in acetonitrile, providing three sets of resonances for each proton in the 1H-NMR spectrum. An inspection of a CPK model indicated that the three structures were sterically allowed to occur by the cis-trans isomerism around the Cys-Sar and Sar-Pro peptide bond. The temperature dependence of the amide proton resonances in 1H-NMR suggested that one γ-turn (1←3 hydrogen bond from the Cys to the Pro) is present in the two conformers, M and m. Thus, the three conformations in acetonitrile were deduced from all of the spectral data. This cyclic tetrapeptide is capable of binding a monovalent cation, Li+, and divalent cations, Mg2+, Ca2+, and Ba2+. Its CD titration curves demonstrated that at least three types of complexes with Ca2+ and Ba2+ were formed. In contrast, Li+ and Mg2+ were shown to form the 1 : 1 complex with this pep tide. The NMR data suggest that the conformational change of the cyclic backbone takes place by changing the geometry of the peptide bonds around the Cys–Sar–Pro sequence on the addition of a metal cation.
The Photochemistry of the Host-Guest Complex. VII. The Photoreaction of Dicyanopyrazine Derivatives Having a Crown Ether Moiety
Authors: Tada Masaru , Hamazaki Hirohide , Hirano Hideki
Published: July 2006

The irradiation of 4′-(5,6-dicyano-2-pyrazinyl)benzo-15-crown-5 and 5,6-dicyano-2-(3,4-dimethoxyphenyl)pyrazine in the presence of a tertiary or secondary amine caused reductive decyanation to give 5-decyano derivatives, which in turn gave bis(decyano) derivatives on further irradiation. Free-energy changes upon single-electron transter from the amine to the excited state of dicyanopyrazine derivatives are exothermic for triethylamine and diethylamine, but endothermic for butylamine. The single-electron transfer was evidenced by the effect of the sodium ion on the quantum yields of the reaction products and the fluorescence quenching.
Synthesis of threo-3-Methylcysteine from Threonine
Authors: Wakamiya Tateaki , Shimbo Kuniaki , Shiba Tetsuo , Nakajima Kiichiro , Neya Masahiro , Okawa Kenji
Published: July 2006

threo-3-Methyl-d-cysteine as a moiety of β-methyllanthionine in the peptide antibiotic nisin was synthesized stereospecifically. The reaction of (2R,3R)-3-methyl-2-aziridinecarboxylic acid derivative prepared from d-threonine with thiobenzoic acid gave the β-mercapto α-amino acid derivative of the same configuration as the starting material. A stereochemistry of the product was retained as a result of double inversion mechanism through the reactions. Thus, we could prepare threo-3-methyl-d-cysteine, i.e., (2S,3S)-2-amino-3-mercaptobutanoic acid which is required for the synthetic study of nisin.
Brillouin Scattering and Ultrasonic Absorption Measurements of Chloroform–Eicosane Mixtures
Authors: Nomura Hiroyasu , Shimizu Hayao , Tanaka Yasuharu , Koda Shinobu , Okunishi Toshio , Kato Shigeo , Miyahara Yutaka
Published: July 2006

An apparatus for the accurate measurement of Brillouin scattering of liquids and solutions was constructed using a multi-pass Fabry-Perot interferometer. The Brillouin scattering spectra of chloroform–eicosane mixtures were obtained at various concentrations. The sound velocity dispersion curves of this system could be expressed by a single relaxation equation. With increasing concentration of eicosane, the relaxation frequency shifted to the higher frequency side, but the relaxation strength was independent of concentration. It is concluded that this relaxation was due to the vibrational-translational energy transfers of chloroform molecules due to the collisions between chloroform and eicosane molecules.
Structure of Tetra-μ-formatodiruthenium Bromide
Authors: Kimura Takashi , Sakurai Tosio , Shima Makoto , Togano Tadashi , Mukaida Masao , Nomura Terunosuke
Published: July 2006

X-Ray structural determination of Ru2(HCOO)4Br showed that the unit cell contains two crystallo-graphically independent formato bridged dinuclear units, Ru2(HCOO)4+, each of which is centrosymmetric. Two adjacent units are bridged by bromide ion to make infinity zigzag chains.
Homologation of Methyl Esters Catalyzed by Ruthenium–Cobalt Bimetallic Systems
Authors: Hidai Masanobu , Koyasu Yukio , Yokota Makoto , Orisaku Masami , Uchida Yasuzo
Published: July 2006

Reactions of methyl esters such as methyl acetate with synthesis gas have been investigated by use of the mixed clusters such as [Et4N][RuCo3(CO)12] and [Et4N][Ru3Co(CO)13] or a combination of Ru(acac)3 and Co2(CO)8 as catalyst and methyl iodide as promoter. In the homologation of methyl acetate, the catalytic activity for formation of ethyl acetate was much improved when both ruthenium and cobalt existed in the reaction system.
Algorithm of Data Processing in Correlation NMR Spectroscopy
Authors: Ozawa Hiroshi , Arata Yoji
Published: July 2006

The algorithm for data processing in correlation NMR spectroscopy has been closely checked. Procedures have been proposed by which one can obtain the spectrum free from artifacts and can carry out phase correction of the spectrum easily.
Chemical Systems Exhibiting Complicated Temporal Oscillations
Authors: Iwamoto Kazutoshi , Kawauchi Susumu , Sawada Kiyoshi , Sen\={o} Manabu
Published: July 2006

Two model systems exhibiting complicated oscillations were proposed and analyzed. One of them is a double oscillation system, which shows alternating oscillations of large and small amplitudes and the mechanism for appearance of the double oscillations is clarified. In the other system, either large or small amplitude oscillation appears depending on the parameter values, and the transition between the large and the small amplitude oscillation is very abrupt and sensitive to the change in external constraints.
A Potentiometric Study on Mixed Ligand Cadmium(II) Complexes with 2-Amino Carboxylic Acids
Authors: Matsui Haruo , Ohtaki Hitoshi
Published: July 2006

Formation constants of mixed ligand cadmium(II) complexes, CdLL′, were determined in aqueous solutions containing 3 mol dm−3 LiClO4 as a constant ionic medium at 25 °C by potentiometric titration, where the ligands HL and HL′ are 2-amino carboxylic acids such as glycine, α-alanine, 2-aminobutanoic acid, 2-aminopentanoic acid, and 2-aminohexanoic acid. Ten kinds of the mixed ligand cadmium(II) complexes were examined with the combination of five 2-amino carboxylic acids. The formation constant, βprs=[CdpLrLs′(2p−r−s)+]⁄([Cd2+]p×[L−]r[L′−]s), of the mixed ligand cadmium(II) complexes containing glycine as one of the ligands lie between those of the parent complexes, while the formation constants of the other complexes are larger than those of the parent complexes. No protonated mixed ligand complex has been observed. The small values of β111 of the Cd(gly)L complexes are due to the considerably small values of the first stepwise formation constants of the CdL+ complexes. On the other hand, the stepwise formation constants of the CdL+ complexes with glycinate ion are larger than the stepwise formation constants with 2-amino carboxylate ions and the second stepwise constant of the bis(glycinato)cadmium(II) complex. Interactions between the ligands through the central cadmium(II) ion are discussed. The b-values (b=log {(K110·K101)⁄(K120·K102)}, where K1rs denotes the stepwise formation constant of the complex CdLrL′s) of the mixed ligand cadmium(II) complexes containing glycinate ion as one of the components lie between 0.93 and 0.98, and are larger than those of the other complexes (b=0.83–0.90), the fact indicating that the mixed ligand glycinato complexes have larger inter-ligand interactions within the complexes than those within complexes containing other 2-amino carboxylate ions. The inter-ligand interaction may occur through the central cadmium ion within the complex.
NMR and CD Spectral Features of Thiaheterohelicenes. Effect of Intramolecular Overlap of Aromatic Rings
Authors: Yamada Koh-ichi , Tanaka Hisao , Nakagawa Hiroko , Ogashiwa Susumu , Kawazura Hiroshi
Published: July 2006

NMR and CD spectral features of a series of thiaheterohelicenes containing alternant thiophene and benzene rings were examined as associated with their helical structures. The terminal ring protons of the thiaheterohelicenes reflected the characteristics of intramolecular overlap of aromatic rings in 1H NMR spectra. With the progression of the helix a sudden chemical shift of the β proton in the end thiophene ring to the higher field occurred, in contrast to carbohelicenes in which the drift of the upfield shift of the corresponding terminal ring proton was gradually suppressed. The CD spectra of thiaheterohelicenes were quite different from those of carbohelicenes. The intensities of the α and β absorption bands weakened with the progressive annelation, whereas the intensity of the p absorption band gradually increased, accompanied by a successive increase in the anisotropy factor of the band. These facts suggest that the structures of thiaheterohelicenes differ from those of carbohelicenes in having a peculiar distortion of the helix.
Collins Oxidation of Methyl (+)-13β-Abiet-8-en-18-oate and Absolute Configuration of Suaveolic Acid
Authors: Matsumoto Takashi , Imai Sachihiko , Yuki Shuhei , Katayama Arata , Furutani Manabu
Published: July 2006

The oxidation of methyl (+)-13β-abiet-8-en-18-oate with Collins reagent yielded nine oxidation products. Their structures were elucidated on the basis of spectroscopic and chemical data to be methyl (−)-14-hydroxy-7-oxoabieta-8,11,13-trien-18-oate (1% yield), methyl (−)-11,14-dioxoabieta-8,12-dien-18-oate (1%), methyl (+)-11-oxo-13β-abiet-8-en-18-oate (18%), methyl (−)-8α,9α-epoxy-7-oxo-13β-abietan-18-oate (2%), methyl (+)-7-oxoabieta-8,11,13-trien-18-oate (2%), methyl (+)-11,14-dihydroxy-7-oxoabieta-8,11,13-trien-18-oate (2%), methyl (+)-7,11-dioxo-13β-abiet-8-en-18-oate (17%), methyl (+)-14-oxo-13β-abiet-8-en-18-oate (15) (4%), and methyl (+)-7-oxo-13β-abiet-8-en-18-oate (23%) respectively. It is noteworthy that oxygenation occurs not only at the C-7 and C-11 positions but also at the C-14 position. The oxygenated products obtained in this studies could be useful intermediates for the synthesis of the oxidized diterpenoids of abietane skeleton. To exemplify this, 15 was converted to methyl suaveolate and suaveolol. Hydrolysis of the former yielded suaveolic acid, thus confirming its absolute configuration to be 4R, 5R, 10S, 13S, and 14S.
Reaction of Haloazoxybenzenes with Sulfuric Acid
Authors: Shimao Ichiro , Fujimori Ken , Oae Shigeru
Published: July 2006

Treatment of 4,4′-dihaloazoxybenzenes with sulfuric acid afforded 4,4′-dihaloazobenzenes (6) as the major product and 5-halo-2-(p-halophenylazo)phenols, the Wallach rearrangement products as minor products, besides 2-halo-5-(p-halophenylazo)phenols, 2-halo-4-(p-halophenylazo)phenols, and 4-(p-halophenylazo)phenols as abnormal rearrangement products. The reaction of fluoro compound gave the azophenols (3a or 5a) in the best yields. However, the ratio of 3a to 5a was found to vary with the concentration of sulfuric acid. Treatment of 4-haloazoxybenzenes with sulfuric acid gave 4-(p-halophenylazo)phenols and 4-haloazobenzenes (13) as major products together with 2-(p-halophenylazo)phenols and 5-halo-2-(phenylazo)phenols as minor products. Yields of reduction products 6 and 13 increased as the halosubstituent became heavier in the following sequence: F→Cl→Br→I.
The Solvomercuration, Bromination, and Related Reactions of 1,5-Dimethyl-6-methylenetricyclo[3.2.1.02,7]oct-3-en-8-one and Its Related Compounds
Authors: Nitta Makoto , Omata Akihiko , Sugiyama Hiroshi
Published: July 2006

The solvomercuration-demercuration reactions of 1,5-dimethyl-6-methylenetricyclo[3.2.1.02,7]oct-3-en-8-one (1), its corresponding alcohol, and 5,8-dimethyl-9-methylenetricyclo[3.3.1.02,8]non-3-en-7-one (2) were investigated. In all cases, the solvent was stereospecifically incorporated on the exomethylene group, and the original tricyclic skeleton did not undergo rearrangement. Similarly, 1 and 2 underwent a stereospecific bromination on the exomethylene group by means of the reaction with pyridinium tribromide. These results suggest the stabilization of the formal cyclopropylcarbinyl cation intermediates by the adjacent acetoxymercury moiety or the bromine atom. On the other hand, the reaction of NBS–MeOH or NBS–H2O with 1 afforded an addition product on the exomethylene group, and 1,4-addition originated from the cleavage of the cyclopropane ring, while with 2 the reaction afforded only an addition product on the exomethylene group. The difference in this reaction mode is discussed on the basis of the solvent effect and the ring strain of 1.
Preparation and Properties of Dealuminated Y Type Zeolite
Authors: Yoshida Akira , Nakamoto Hiromi , Okanishi Kazuhito , Tsuru Tatsuro , Takahashi Hiroshi
Published: July 2006

The removal of aluminium cations from Y type zeolite, faujasite, was studied by means of three methods of treatment, i.e., acetic acid–sodium acetate buffer treatment, acetate buffer–Na2H2EDTA treatment and H4EDTA treatment. It was confirmed from the results that the reagent for dealumination of faujasite should have two functions, i.e. weakly acidic and chelating ability with aluminium cations. When more than 23 aluminium cations were extracted from 53 aluminium atoms in a unit cell, lattice was seriously destroyed. But the analysis of the adsorption isotherms suggested that more than 66% of α-cages remained even in a nearly amorphous sample obtained after dealumination as far as 75%. The differential heat of immersion of the dealuminated Y type zeolite in water showed that the acid strength of the surface increased slightly by dealumination.
Determination of Thermodynamic Properties of Diaspore from Its Solubility Data in NaOH Solutions
Authors: Chang Byong-Tae
Published: July 2006

Thermodynamic properties of diaspore in the alkaline pH range were determined from its solubility data in NaOH solutions by a method presented earlier by the author. The ionic solubility product, Ks°=aA1aH⁄aw2, of diaspore was found to depend upon temperature between 280 and 325 °C as follows: logKs°=−1367⁄T–8.67.
The Structure of Alnuserrutriol, a New C31 Dammarane-type Triterpenoid from the Male Flowers of Alnus serrulatoides
Authors: Hirata Toshifumi , Ideo Reiko , Aoki Tadashi , Suga Takayuki
Published: July 2006

The structure of a new C31 dammarane-type triterpenoid, alnuserrutriol, isolated from the male flowers of Alnus serrulatoides CAll. (Betulaceae) has been elucidated to be (3S,12R, 20S)-3,12,20-trihydroxy-24-methylenedammarane by a combination of chemical and spectroscopic methods.
Mechanochemical Reactions at High Pressures. II. Reaction of Methacrylamide
Authors: Okuri Yasuhiro , Ogo Yoshiaki
Published: July 2006

The mechanochemical behavior of methacrylamide was investigated at room temperature and at static pressures of up to 15 kbar. The determinations of the IR spectrum, the ESR signal, the X-ray diffraction pattern, and the molecular weight by GPC apparatus confirmed that the reaction products were amorphous polymethacrylamide. The reaction of methacrylamide under conditions of high pressure combined with simultaneous shear deformation(HP+SSD) is a free radical polymerization. The concentration of radicals of polymethacrylamide and the relation between the conversion and the shearing degree suggest that an acrylamide crystal is less stable than one of methacrylamide. Methacrylamide was not reached 100% conversion even at about 2π rad shearing.
Effect of Mixed Surfactant upon Stability and Particle Size of Emulsion
Authors: Ogihara Kimihiko , Ueno Minoru , Meguro Kenjiro
Published: July 2006

An effect of a mixed surfactant of SDS and homogeneous octaethylene glycol dodecyl ether (8ED) upon the stability and particle size of an octane-in-water emulsion was studied. The mixed surfactant solutions were found to exhibit equi-interfacial-tension over a wide concentration region of a mixed 8ED; the SDS concentrations were 6, 8, and 20 mmol dm−3. The emulsion prepared by using mixed surfactant solution in such a concentration region showed a similar mean particle size. When SDS concentration was kept at 8 or 20 mmol dm−3, The emulsions prepared by the mixed surfactant solutions had similar stability, independently of the mixed 8ED concentration. In the presence of 1 mmol dm−3 of SDS, the stability of the emulsions increased with the increasing concentration of mixed 8ED. In the case of SDS concentration of 6 mmol dm−3, the emulsion was most stable at 1×10−3 mol dm−3 of mixed 8ED.
Investigation on the Complex Formation of Some Lanthanoids(III) and Actinoids(III) with Chloride and Bromide
Authors: Fukasawa Tetsuo , Kawasuji Isamu , Mitsugashira Toshiaki , Satô Akiko , Suzuki Shin
Published: July 2006

Stability constants (β1 and β2) of the chloro and bromo complexes of tervalent Sm, Eu, Gd, Tb, Ac, Am, Cm, Bk, and Cf were determined by a solvent extraction method under the conditions of ionic strength and acidity to be 3.0 and 0.15 M (1 M=1 mol/dm3), respectively. Stability constants obtained were discussed with respect to the formation mechanism. A much larger contribution from the inner sphere complex formation was observed in chloro complexes than bromo complexes on tripositive actinoids.
Electrochemical Study of Reaction of Hyperoxide with Tris(1,10-phenanthroline)iron(II) in Dimethyl Sulfoxide
Authors: Umemoto Kisaburo , Saeki Toyohumi , Matsuura Niro , Motegi Katsue
Published: July 2006

Reaction of hyperoxide with Fe(phen)32+ in DMSO was studied by polarography, cyclic voltammetry, and spectroscopy. Voltammetric study of oxygen showed that disproportionation of hyperoxide is promoted by Fe(phen)32+. Controlled potential coulometry exemplified the stoichiometry of the reaction to be 2:1 for hyperoxide to Fe(phen)32+ in support of the proposed disproportionation mechanism of hyperoxide. Analysis of reaction products proved that Fe(phen)32+ decomposes on reaction with hyperoxide in DMSO; the reaction products were iron(III) hydroxide and liberated ligands, neither metal hyperoxide nor oxygen bridged metal complexes being detected.