bluuebunny/crossref_metadata_2025 huggingface dataset:
The Solubility of Ball-milled Amobarbital and the Stability of Its Amorphous State
Authors: Ikekawa Akiko , Hayakawa Sohachiro
Published: July 2006

Amobarbital was ball-milled with methylcellulose (MC), microcrystalline cellulose, or dextran. The analysis of the IR spectra indicated that hydrogen bonds were formed between the C=O groups of amobarbital and the OH groups of the diluents upon ball-milling. It was also shown that formation of the bonds was more predominant with MC than with dextran. After suspensions of various kinds of samples in distilled water had been set aside for a week after the time of preparation, the solid state of the amobarbital remaining undissolved in the suspension was compared with the state before dissolution. There are three kinds of polymorphs for amobarbital: Crystals I, II, and III. Crystal I is given by heating Crystal II (at 150 °C), which has been recrystallized from a 25 v/v% aqueous ethanol solution. Crystal III is given by freeze-drying an aqueous solution. The above comparison suggests that Crystal III and the amorphous part are transformed into Crystal I in the absence of any diluent. It seems that the presence of dextran ball-milled with amobarbital prevents Crystal III from being transformed into Crystal I. The presence of MC ball-milled with amobarbital also seems to prevent both the amorphous part from crystallization and Crystal III from transformation into Crystal I. The solubility of amobarbital in distilled water increased remarkably upon ball-milling with diluents; this was attributed to the stabilization of the amorphous state by the interaction with diluents.
Thermal Stability Enhancement of Liquid-crystal Phase by Chargetransfer Interaction in Binary Mixtures. Application of Solid-solution Model
Authors: Iida Yôichi
Published: July 2006

Phase transition in liquid crystal of binary mixture consisting of electron donor and acceptor was examined by using modified solid-solution model. The charge-transfer interaction between donor and acceptor is essential for parallel molecular arrangement in liquid crystal, resulting in thermal stability enhancement of mesophase in binary mixture.
Synthesis and Characterization of Substituted Derivatives of (Tetraazacycloalkadienato)nickel(II) Complexes with Uninegative Ligands, and Crystal Structure of Parent Complex [Ni(Me2[14]dienatoN4)]Br·H2
Authors: Matsumoto Naohide , Wakizaka Kenichiro , Ohyoshi Akira
Published: July 2006

The (tetraazacycloalkadienato)nickel(II) complexes [Ni(Me2[Z]dienatoN4)]+ (Z=13, 14), which have an unsaturated chelate ring containing nucleophilic center, react with electrophilic reagents such as benzoyl chloride. p-methylbenzoyl chloride, and p-nitrobenzoyl chloride to give the substituted derivatives [Ni(Me2E[Z]dienatiN4)PF6. These complexes have been characterized by elemental analyses, 1H NMR, infrared, and electronic spectra. One of the parent complexes [Ni(Me2[14]dienatoN4)]Br·H2O has been subjected to the single-crystal X-ray diffraction technique and its structural data indicated that the average Ni–N bond distance is longer than that of the corresponding thirteen membered complex.
Preparation of Poly(dicarbon monofluoride) from Petroleum Coke
Authors: Watanabe Nobuatsu , Ashida Yoshinori , Nakajima Tsuyoshi
Published: July 2006

Graphite fluoride containing more than 60% poly(dicarbon monofluoride) (C2F)n was prepared from petroleum coke heat-treated at 2700 °C at a temperature between 337 and 460 °C. The interlayer spacings and F/C ratios of these graphite fluorides were in the ranges of 0.8–0.74 nm and 0.58–0.68, respectively. The (C2F)n content in graphite fluoride also increased with increasing fluorine pressure.
Bromination of Methoxybiphenylenes
Authors: Kidokoro Hiroto , Sato Masaru , Ebine Seiji
Published: July 2006

Bromination of 2-methoxybiphenylene derivatives did not give biphenyl derivatives but benzocyclooctene derivatives. 1-Methoxybiphenylene, on the other hand, was brominated to give the benzobicyclo[4.2.0]octadienone derivatives.
Michael Additions Catalyzed by Metal(II) Complexes
Authors: Watanabe Ken-ichi , Miyazu Ken-ichi , Irie Kazuo
Published: July 2006

Michael-addition reactions have been found to proceed in the presence of the Ni(OAc)2 or Co(OAc)2-2,2′-bipyridine complex in DMF under neutral conditions at room temperature without any by-product. The reactions of chalcone and its derivatives with nitromethane generally gave good results. The effects of metal(II) ions, ligands, counter ions, and solvents on the catalysis were examined, and the features of the metal-complex-catalyzed Michael reactions were studied, with some considerations also being given to the catalysis mechanism.
Confirmation of the Sector Rule of the Benzenoid Chromophore
Authors: Hagishita Sanji , Kuriyama Kaoru
Published: July 2006

1,2,3,4,4a,9,9a,10-Octahydroanthracene and tetralin derivatives with known absolute configurations were synthesized to estimate the contribution of a methyl substituent at the third sphere to the Cotton effect induced in the benzenoid transitions. The contributions were estimated from the CD spectra obtained based on the conformation of the skeleton deduced by Force Field Theory and the assumption that the contributions are additive. A large contribution was observed for the 1-quasiequatorial-methyl group in the 1Lb benzenoid transition and for the 2-axial-methyl group in the 1La benzenoid transition. The sign agreed well with the rule proposed by Snatzke except for the contribution of ring B in the 1La benzenoid transition.
Kinetics of Gas Phase Addition Reactions of Trichlorosilyl Radicals. IV. Relative Rates of Additions to 1-Alkenes
Authors: Dohmaru Takaaki , Nagata Yoshio
Published: July 2006

Trichlorosilyl radical additions to a mixture of ethene, propene, 1-butene, and 1-pentene and to a mixture of propene and 2-methylpropene have been investigated. The rate of adduct formation from each olefin was obtained relative to that from propene between 403 K and 548 K. These relative rates are in good agreement with those calculated from the rate parameters obtained previously in this laboratory.
Studies on 2-Aziridinecarboxylic Acid. VIII. Total Synthesis of Actinomycin D and Its Serine Analogue via Ring-opening Reaction of 1-Benzyloxycarbonyl-2-aziridinecarboxylic Acid Moiety
Authors: Nakajima Kiichiro , Tanaka Takumi , Neya Masahiro , Okawa Kenji
Published: July 2006

Direct synthesis of peptides containing 1-benzyloxycarbonyl-2-aziridinecarboxylic acid were carried out by the reaction of β-hydroxy-α-amino acid peptides with DEAD–TPP reagents, and key O-peptide intermediates of actinomycin D synthesis were prepared via a ring-opening reaction of the aziridine with N-protected dipeptide. Peptide lactone was prepared by the DCC–HOBt method, and the subsequent debenzyl procedure and oxydation procedure gave the title compounds in good yields.
Synthesis and Oxidative Cyclization of 3-(1-Cycloalkenyl)tropolones
Authors: Imafuku Kimiaki , Inoue Kyoko
Published: July 2006

3-(1-Cyclopentenyl)-, 3-(1-cyclohexenyl)-, and 3-(1-cycloheptenyl)tropolones (3a, 3b, and 3c) were prepared by the hydrolysis of cycloadducts of dichloroketene to cyclopentylidene-, cyclohexylidene-, and cycloheptylidenecyclopentadiene, respectively. Compound 3a was oxidized with performic acid to give 1,2,3,5-tetrahydrocyclohepta[b]cyclopenta[d]furan-5-one and 3-(2-oxocyclopentyl)tropolone. Oxidation of 3b and 3c gave 1,2,3,4-tetrahydro-6H-cyclohepta[b]benzofuran-6-one (4b) and 5,7,8,9,10,11-hexahydrodicyclohepta[b,d]furan-5-one, respectively. Dehydrogenation of 4b with palladium catalyst gave 6H-cyclohepta[b]benzofuran-6-one.
A Novel Synthesis of a Branched-chain Amino Sugar, Methyl 2-Amino-2,3-dideoxy-3-C-formyl-α-d-xylofuranoside-3′R,5-hemiacetal
Authors: Tatsuta Kuniaki , Miyashita Satoru , Akimoto Kohji , Kinoshita Mitsuhiro
Published: July 2006

Methyl 2-amino-2N,3O-(o-benzenedisulfonyl)-2-deoxy-α-d-glucopyranoside, which was prepared from methyl 2-amino-2-deoxy-α-d-glucopyranoside and o-benzenedisulfonyl dichloride, was treated with sodium methoxide to afford exclusively a branched-chain amino sugar, methyl 2,3-dideoxy-3-C-formyl-2-(o-sulfobenzenesulfonyl)amino-α-d-xylofuranoside-3′R,5-hemiacetal sodium salt (6). Some derivatives were synthesized from 6.
The Photoreduction and Photosensitized Reduction of Dyes Bound to a Surfactant Micellar Surface
Authors: Usui Yoshiharu , Saga Kazuhiko
Published: July 2006

The photochemical reduction of thionine(Th) and Methylene Blue(MB) bound to anionic sodium dodecyl sulfate(SDS) micelles in an aqueous solution was inhibited at the lower concentration range of a reductant anion, EDTA, because of the electrostatic repulsion between the micelles and the reductant. The concentration dependence of EDTA on the quantum yield of photoreduction has shown to be, anomalously a sigmoidal type: this is explained by mechanistic interpretation based on the cooperative effects of the ionic strength and the essential concentration of EDTA. The enhancement effect for the quantum yield of the photoreduction of eosine bound to a cationic micelle by the EDTA anion was conversely observed, because of the electrostatic attraction. When 10-dodecyl) (Acridine Orange) was incorporated into SDS micelles in water containing EDTA and ascorbic acid, and the mixture was excited, the photosensitized reduction of MB bound to the micelles occurred. It was found that the quantum yield of the sensitized reduction depended on the concentration of MB and was larger than the yield on the direct excitation of MB.
Preparation and Electrical Properties of Eu(II)xNb(IV)O2+x
Authors: Ishikawa Kenji , Adachi Gin-ya , Shiokawa Jiro
Published: July 2006

Nonstoichiometric compounds, EuxNbO2+x, were prepared. A cubic tungsten bronze type structure was found in the single phase region of EuxNbO2+x (0.5≤x≤1.0). Magnetic susceptibility measurements showed that the oxidation state of europium in the bronzes was bivalent. The EuxNbO2+x was a metallic conductor in the temperature range 4.2–300 K. Thermoelectromotive force measurements (100–350 K) indicated that the charge carriers were electrons and that the effective mass of the electrons increased with decreasing x in EuxNbO2+x.
Comment on Momentum Distributions of Valence Electrons of Atoms and Simple Molecules
Authors: Suzuki Isao H , Brion C E
Published: July 2006

The relationship between vertical ionization potentials and experimental electron momentum distributions of individual valence orbitals has been examined in some series of orbitals with the same characteristics of atoms and simple molecules. It has been found that effectively pure s- and p-orbitals show trends consistent with the predicitions of the virial theorem.
Standard Enthalpies of Combustion and Vaporization of N,N-Dimethylaniline
Authors: Furukawa Jun-ichi , Sakiyama Minoru , Seki Syûzô , Saito Yoshihiro , Kusano Kazuhito
Published: July 2006

Standard energy of combustion and standard enthalpy of vaporization of N,N-dimethylaniline have been determined by oxygen bomb combustion calorimetry and vaporization calorimetry, respectively. Derived standard enthalpies at 298.15 K are as follows: ΔHc°(1)=−(4767.8±3.2), ΔHf°(1)=(47.7±3.4), ΔHv°=(52.83±0.03), and ΔHf°(g)=(100.5±3.4) kJ mol−1, respectively.
Synthesis of Polymethyl Crown Ethers. A New Class of Lipophilic Crown Ethers
Authors: Ikeda Isao , Yamamura Shingo , Okahara Mitsuo
Published: July 2006

A new class of lipophilic polymethyl crown ethers were synthesized from oligopropylene glycols via the intramolecular cyclization, and the stability constants of some complexes in methanol were determined.
Reaction between Enamines and Schiff Basess. Evidence for the Thermal [2+2] Cycloaddition Reaction
Authors: Nomura Yujiro , Kimura Muneaki , Shibata Tomoyuki , Takeuchi Yoshito , Tomoda Shuji
Published: July 2006

Reaction between 4-(1-phenyl-1-propenyl)morpholine and N-benzylideneanilines provided N-(3-aryl-2-methyl-1-phenylallylidene)anilines in 60–65% yields, which unequivocally established the initial [2+2] cycloaddition reaction between enamines and Schiff bases.
Photochemical Reactions in Polyethylene Glycol. 2. Photo-induced Nucleophilic Substitution of Dimethoxybenzenes in the Presence of Polyethylene Glycol
Authors: Suzuki Nobutaka , Ayaguchi Yasuo , Izawa Yasuji
Published: July 2006

Polyethylene glycol can replace crown ether as co-solvent for photochemical substitution reactions of dimethoxybenzenes with KCN in CH2Cl2 in either the presence or the absence of terephthalonitrile.
A Method for the Determination of Mutual Diffusion Coefficients of Electrolytes in Water by Means of Conductivity Measurements
Authors: Kamakura Katsuyoshi
Published: July 2006

A method for determining diffusion coefficients of electrolytes was studied by the use of a conductance cell made of a Pyrex glass tube (4–7 cm in diameter and 6.5 cm in length). A pair of platinized platinum electrodes are sealed into the tube at a position 10 mm below the top of the glass tube. The diffusion was carried out from solution in the cell to an outer solvent, and the rate was measured from the decrease in conductance at a fixed position in the cell. In the graphical relation between the measured diffusion coefficient and the time, the differential diffusion coefficient at the initial concentration of the diffusing solution was estimated by extrapolation of the linear portion of the plot to time→0. The differential diffusion coefficients obtained in 0.1 mol dm−3 solutions at 25 °C were as follows: HCl, (3.12±0.08)×10−5; KI, (1.909±0.020)×10−5; NaCl, (1.520±0.016)×10−5; 1/2Na2SO4, (1.059±0.028)×10−5; CuSO4, (0.610±0.033)×10−5 cm2 s−1.
An Evaluation of the Effective HLB of Surface-active Crown Compounds
Authors: Kuo Ping-Lin , Ikeda Isao , Okahara Mitsuo
Published: July 2006

The hydrophilicity of surface-active crown compounds and their change upon the addition of electrolytes were investigated by measuring the phase-inversion temperature (PIT), the phenol index, and the cloud point. Sodium chloride and potassium chloride were observed to raise the hydrophilicity of 15-crowns and 18-crowns respectively, in contrast with their lowering effect on the hydrophilicity of usual poly(oxyethylene)-type nonionics. The effective HLBs of dodecyl crown ethers, estimated from both the PIT and the phenol index, were compared with those of poly(oxyethylene) dodecyl ethers, and the hydrophilicity of the crown rings were discussed in conjunction with that of the poly(oxyethylene) chain.
Effect of Adsorption by Cellulose Acetate Membrane on Reverse Osmosis of Some Monoamino Monocarboxylic and Monoamino Dicarboxylic Acids in Aqueous Solutions
Authors: Tozawa Osami , Nomura Danji
Published: July 2006

Taft’s polar and steric parameters, Σσ*, ΣEs, and nonpolar parameter, ΣS* governing the reverse osmosis of nonionized polar aliphatic and alicyclic organic compounds using a cellulose acetate membrane were also applicable to aliphatic monoamino monocarboxylic acids having zwitter ion structure. These three parameters were further extended so as to include the cases of sulfur-containing amino acids, hydroxy-substituted, and aromatic type amino acids. Reverse osmosis of monoamino monocarboxylic acids in binary aqueous solution systems containing l-alanine was carried out. As a result, added amino acids were adsorbed by the membrane when added in low concentration (<0.001 mol dm−3), and the permeation of l-alanine was governed by the difference of Taft’s polar parameter between l-alanine and the added amino acid. Reverse osmosis of monoamino dicarboxylic acids indicated that hydrogen ions were adsorbed by the membrane, and the adsorption isotherms of hydrogen ions were approximately represented by the Langmuir formula for each amino acid. The electrostatic repulsion between R− ionic species in monoamino dicarboxylic acid and the negatively dissociated groups of the membrane was weakened by neutralization of the membrane by hydrogen ion adsorption, resulting in decreased amino acid rejection. It was noted that the ultraviolet spectrum and the titration curve of permeate of amino acids were different from those of the feed solution; relationship between this phenomenon and adsorption of hydrogen ions was investigated.
Estimation of Parameters, G11, G22, and G12 in the Kirkwood-Buff Solution Theory on the Basis of the Concentration Fluctuation Data Obtained from Rayleigh Scattering
Authors: Kato Tadashi , Fujiyama Tsunetake , Nomura Hiroyasu
Published: July 2006

A concentration fluctuation value obtained from Rayleigh scattering intensity was confirmed to give a thermodynamic quantity of an equilibrium system. An observation of concentration fluctuation by a light scattering method was found to be the most direct and useful way of determining a concentration derivative of a chemical potential. For methanol, ethanol, and 1-propanol–carbon tetrachloride systems, the Kirkwood-Buff parameters, G11, G22, and G12, were determined by the use of concentration fluctuation data. The structure of these systems was discussed on the basis of the calculated Kirkwood-Buff parameters.
ortho-Disubstituted F-Benzenes. IV. The Formation of 2-Acyl-F-phenyl Carboxylates from (F-Benzo)furans by the Oxidative Cleavage of the Furan-ring
Authors: Inukai Yoshinari , Sonoda Takaaki , Kobayashi Hiroshi
Published: July 2006

2,3-Diphenyl-, 2-phenyl-3-methyl-, and 2-methyl-3-phenyl(F-benzo)furans were oxidized with chromium trioxide in acetic acid to yield 2-benzoyl-F-phenyl benzoate, 2-acetyl-F-phenyl benzoate, and 2-benzoyl-F-phenyl acetate respectively, while 2-phenyl(F-benzo)furan was least susceptible to the same reagent, affording 1-(2-hydroxy-F-phenyl)-2-phenylethanedione in a poor yield. The spectral data of the products were compatible with the structure of ortho-disubstituted F-benzene.
Asymmetric Adsorption of Alanine by Quartz Powder from Ethanol Solution
Authors: Furuyama Shozo , Sawada Michio , Hachiya Kinji , Morimoto Tetsuo
Published: July 2006

The asymmetric adsorption of the racemic alanine by the optically active quartz from ethanol solution at 8 °C was studied by the 14C-tracer method and the newly developed 14C-tracer·ninhydrin-colorimetry combination method. The preferential adsorption of l-alanine by levorotatory quartz (l-quartz) and d-alanine by dextrorotatory quartz (d-quartz) was confirmed. The asymmetric adsorptivity (As) falls in the range of 1.1–1.3, which is comparable with the value determined at −80 °C in the previous paper. The effects of water content in the ethanol solution and of the adsorption temperature upon the adsorption affinity of alanine to quartz were also measured. The cause for the asymmetric adsorption is discussed from the crystallographic point of view.
Studies of Unusual Amino Acids and Their Peptides. XIV. The Asymmetric Hydrogenation of the Phenylhydrazone of Methyl N-(3,3-Dimethyl-2-oxobutanoyl)-l-valinate
Authors: Miyazawa Toshifumi , Takashima Katsumi , Yamada Takashi , Kuwata Shigeru , Watanabe Hiroshi
Published: July 2006

The asymmetric hydrogenation of the phenylhydrazone of methyl N-(3,3-dimethyl-2-oxobutanoyl)-l-valinate was investigated using palladium catalysts. The configuration of the newly formed t-leucine moiety was found to be l.
Selective Hydrogenation of Cyclic Diolefins to Monoolefins Catalyzed by a Nickel Complex
Authors: Sakai Mutsuji , Harada Fumiya , Sakakibara Yasumasa , Uchino Norito
Published: July 2006

Cyclic diolefins were hydrogenated selectively to monoolefins with a nickel catalyst prepared from bis(acetylacetonato)nickel(II), triethyldialuminium trichloride, and triphenylphosphine at 40 °C under an atmospheric hydrogen pressure.
Kinetic Studies of the Electron Transfer Reactions in Iron(II) and Iron(III) Systems. XII. The Ratios of the Reaction Rates of the Outer-sphere vs. Inner-sphere Electron Transfer Mechanisms in the Presence of X− (X−=Cl−, SCN−, and N3−) in Aqueous Solutions, as Judged from the Kinetics of the Dissociation Reactions of FeX2+
Authors: Wada Goro , Inatani Tomiko , Ichimura Sachiko
Published: July 2006

The electron transfer reactions between Fe2+ and FeX2+ (X−=Cl−, SCN−, or N3−) may take place through the inner- or outer-sphere mechanism or through both in parallel. The process of the outer-sphere mechanism is just equivalent to the process of dissociation of FeX2+ catalyzed by Fe2+ in appearance. When the overall rate constant of the electron transfer reaction and the rate constant of Fe2+-assisted dissociation reaction of FeX2+ are denoted by kE and ko respectively, the fraction r of the outer-sphere mechanism to the total is given in terms of r=2ko⁄kE. Thus, the r values were determined with the results that r(Cl−)=44% at I=1.5 M (1 M=1 mol dm−3) and 25 °C, r(SCN−)=100% at I=0.5 M and 25 °C, and r(N3−)=0% at I=0.55 M and 10 °C. These facts suggest that r depends considerably upon the bridging ability of X−; formation of binuclear intermediate may be favored by the symmetrical structure and the size of X−, which make the inner-sphere mechanism easier with the stronger coordinate bond and the weaker electric repulsion between the two reactants beyond the bridging ligand.
Pyrolytic Sulfurization Gas Chromatography. XII. The Simultaneous Determination of the Atomic Ratio between C, H, O, and N in an Organic Compound at the Centimilligram Level
Authors: Hara Tadashi , Okui Fujio
Published: July 2006

The atomic ratio between C, H, O, and N in an ordinary organic compound and a metal organic chelate compound could be simultaneously and satisfactorily determined by the use of 30–130 μg of a sample which cannot be accurately weighed by a microbalance or an ultramicrobalance. This was done by adopting the following modifications: 1) The amount of S was reduced to 0.5 mg from the 5 mg used in the previous studies; 2) the stainless steel column in the gas chromatograph was replaced by a Teflon column; 3) the poly(vinyl chloride) and silicone rubber tubes were replaced by stainless steel and copper tubes; and 4) a correction procedure was established for the analysis of a small amount of a sample.
Characterization of Cobalt(III) Complexes with l-Penicillaminate. Crystal Structure of (Diethylenetriamine)(l-penicillaminato)cobalt(III) Chloride Monohydrate
Authors: Okamoto Ken-ichi , Wakayama Katsuhiko , Einaga Hisahiko , Ohmasa Masaaki , Hidaka Jinsai
Published: July 2006

The crystal structure of the title complex, which was chromatographically obtained as the first eluted isomer, has been determined by the X-ray diffraction method. The dark-brown needle crystal was hexagonal, space group P61, a=21.035(5), c=6.459(3) Å, Z=6, and the final R value was 0.076 for 1504 non-zero reflections. Of three possible isomers for the (diethylenetriamine)(l-penicillaminato)cobalt(III) complex, the complex isolated has trans(N1N) configuration. The average Co–N distance for the nitrogen atoms bonded cis to the sulfur atom is 1.961 Å, whereas the trans Co–N length is 2.007 Å.
Spectroscopic Studies of Copper(I) Complexes of 1,8-Di(2-pyridyl)-3,6-dithiaoctane in a Nonaqueous Solvent. The Halide-ion Effect on Their Structure
Authors: Kitagawa Susumu , Munakata Megumu , Okada Shoji
Published: July 2006

The complexes of 1,8-di(2-pyridyl)-3,6-dithiaoctane(pdto) with CuX(X=Cl and Br) and [Cu(CH3CN)4]ClO4 have been synthesized in chloroform, methanol, ethanol, and acetone. Their absorption spectra show an intense metal-to-ligand charge-transfer band at 307 nm: This band is assigned to pyridyl nitrogen←Cu. [Cu(pdto)]+ (1) has been prepared from [Cu(CH3CN)4]ClO4, its pdto acting as a four-coordinate ligand. CuX reacts with pdto to yield two complexes: One is 1, and the other is [CuX(pdto)] (2). Both complexes are four-coordinate, but in the 2 one of the two pyridyl groups is dissociated. The complex 2 is unstable and is oxidized by oxygen. Neither complex reacts with CO, indicating the tight binding of pdto with Cu(I). The 1 and 2 are equilibrated in solution. The 1H NMR spectra well demonstrate that 2 is dominant in chloroform and that 1 is the principal form in alcohol, while the 1/2 ratio is 3/7. This solvent-dependence is ascribed to the coordination ability and/or polarity of the solvent.
Graphite Furnace Atomic Absorption Spectrometry with a Tantalum Boat for the Determination of Yttrium, Samarium, and Dysprodium in a Mish Metal
Authors: Daidoji Hidehiro , Tamura Shohei
Published: July 2006

The determination of yttrium, samarium, and dysprodium by means of graphite-furnace atomic absorption spectrometry (AAS) was studied by a tantalum boat inserted into a graphite tube atomizer. These elements could not be determined by the use of a commercial graphite tube. In the atomization from a tantalum boat, better analytical sensitivities and negligible memory effects for these rare earths are obtained. The analytical sensitivities of yttrium, samarium, and dysprodium with the tantalum boat were 0.60 ng, 0.86 ng, and 0.17 ng respectively. This method was applied for the determination of yttrium, samarium, and dysprodium in a mish metal. The measurements were performed with slightly acidified solutions (0.01 mol dm−3 HCl or HNO3). The sensitivities and the precisions for these elements decreased with increasing acid concentration. An enhancement in the sensitivities of yttrium and dysprodium upon the addition of a large excess of lanthanum, neodymium, and praseodymium salts were observed. The yttrium, samarium, and dysprodium in a mish metal were determined with both analytical curves of standard solutions containing an excess of lanthanum, cerium, and neodymium ions and of the standard addition. The precisions for this work were in the 3–9.3% range.
Spectrophotometric and Electrochemical Investigations of [Tetrakis(1-methylpyridinium-4-yl)porphine]iron(III) Ion in Aqueous Solution
Authors: Kurihara Hirondo , Arifuku Fumihiro , Ando Isao , Saita Minoru , Nishino Rika , Ujimoto Kikujiro
Published: July 2006

The equilibria among the species of [tetrakis(1-methylpyridinium-4-yl)porphine]iron(III) ion (Fe(III)–TMPyP) in aqueous solution and the redox reactions of their central metals were investigated by means of spectrophotometric, electrochemical and spectroelectrochemical methods. Two acid-dissociation equilibria involving three monomeric species of Fe(III)–TMPyP were found: one with a pKa of 5.5 and the other with a pKa of ca. 12. After electrochemical reduction, an equilibrium between two monomeric species of Fe(II)–TMPyP with a pKa of 11 was observed. In the Fe(III)–TMPyP solution at relatively high concentration, two additional different species, probably dimeric, were found in the pH regions of 5–8 and 9–13, respectively. The consistency of specification of the species with the scheme of redox reactions is discussed.
Photochemical Reaction of 4-Hydroxy-diphenylamine with Polychloromethane
Authors: Hinohara Tadao , Amano Kazuo
Published: July 2006

The main photochemical reaction of 4-hydroxy-diphenylamine (R) in the aerated cyclohexane wa photocyclization. In the presence of polychloromethane (Q), however, photooxidation to N-phenyl-p-benzoquinone monoimine (PBQI) took place instead of the photocyclization. The formation of PBQI was in parallel with the quenching of fluofescehce by Q, and it was proposed that both PBQI formation and fluorescence quenching by Q proceed via exciplex, (R+Q−)*, which is nonfluorescent. The kinetic analysis based on this reaction mechanism gives the fluorescence quenching constant, which is in good agreement with the value obtained directly from the fluorescence quenching study. This agreement strongly supports the validity of the proposed reaction mechanism.
Studies on Catalytic Activity of Chelating Resins. I. The Catalytic Activity of Resin–Metal Chelates for the Oxidation of 2,6-Dihydroxyphenylacetic Acid and Hydroquinone
Authors: Egawa Hiroaki , Nonaka Takamasa , Kozakura Noboru
Published: July 2006

Some crosslinked chelating resins were prepared and the catalytic activity of the resin-rnetal chelates for the oxidation; of 2,6-dihydroxyphenylacetic acid(homogentisic acid) and hydroquinone was investigated. The resin–Cu(II), resin–Au(III), and resin–Ag(I) chelates had a high catalytic activity. Especially resin–Cu(II) chelate had the highest catalytic activity for these oxidation reactions, and its activity did not decrease even after repeated use. The chelating resins having hydrazide or polyethylenepolyamine side chains had a high catalytic activity. In order to have a high catalytic activity, the resin–metal chelates must leave coordination places open for the substrate to coordinate to metal in the chelates. In the oxidation of homogentisic acid, the catalytic activity of gel type resin increased with the increase of crosslinking degree in the range from 0.5% to 7.5%. However, the catalytic activity of the macroreticular chelating reins was scarcely affected by the degree of crosslinking. The oxidation reaction of homogentisic acid showed a kinetic behavior of a typical Michaelis-Menten type.
The Fusion Synthesis of Aryl 1-Thioglycosides
Authors: Shimadate Toshisada , Chiba Sachiyo , Inouye Kazuko , Iino Teruhiko , Hosoyama Yoshiyuki
Published: July 2006

A simple method for the preparation of aryl 1-thioglycosides is described. The reaction of d-glucose pentaacetate or 2-acetamido-2-deoxy-d-glucose tetraacetate with arenethiols in the presence of zinc chloride under fusion conditions formed their 1-thioglycosides in good yields. Some Lewis acids in addition to zinc chloride were studied as catalysts in the reaction.
Reaction of Diketene with Grignard Reagents in the Presence of Cobalt Catalyst. A Convenient Method for the Synthesis of 3-Methylenealkanoic Acids Leading to Terpenoids
Authors: Fujisawa Tamotsu , Sato Toshio , Gotoh Yoshihiko , Kawashima Masatoshi , Kawara Tatsuo
Published: July 2006

Primary alkyl Grignard reagents react regioselectively with diketene in the presence of cobalt(II) iodide to afford 3-methylenealkanoic acids in good yields. The synthetic utility of this reaction is demonstrated in the syntheses of terpenoids by two methods. Utilizing the isomerization of double bond of 3-methylenealkanoic acids, geranic acid and farnesic acid were obtained in two steps. Another method, the tandem [3,3] sigmatropic rearrangement of the corresponding allylic esters was used for the synthesis of C18-Cecropia juvenile hormone.
Implications of X-Ray Crystallographic Results of 1,2,3,4-Tetrachloro-9-(2-oxopropyl)triptycene Rotamers
Authors: Nogami Norimasa , Oki Michinori , Sato Shoichi , Saito Yoshihiko
Published: July 2006

Crystals of 1,2,3,4-tetrachloro-9-(2-oxopropyl)triptycene grown from tetrahydrofuran-hexane were found to contain 1:1 ap and ±sc rotational isomers about the C9–CPr bond by the X-ray diffraction method. The molecular structures had the following features. The acetyl group in the 9-substituent takes an O-inside, relative to the triptycene skeleton, conformation in both forms. The benzene rings are deformed by the steric effect to form boats. The 2-oxopropyl groups in both forms were planar within the experimental error but the C2–C1 bond in the 2-oxopropyl group was appreciably shorter in the ±sc conformation than that in the ap. The results are discussed on the ground of steric repulsion and the existence of the interaction between the C=O and the Cl groups which are located only 3.035 Å apart in the ±sc form.
Reactions of 4,5-Dicyanoimidazoles with Isocyanates. Novel Formation of the Condensed Tricyclic Imidazoles
Authors: Mitsuhashi Keiryo , Takahashi Kazuyuki , Kawahara Takeo , Ikeru Yoshimitsu , Tanaka Kiyoshi
Published: July 2006

The reactions of 4,5-dicyanoimidazoles with methyl isocyanate gave 7-cyano-1-imino-2-methyl-2,3-dihydro-1H-imidazo[3,4-c]imidazol-3-ones (2), while the similar reactions with phenyl isocyanate resulted in the formation of the tricyclic imidazoles, 1 1-imino-6,10-diphenyl-2,4,6,8,10-pentaazatricyclo[5.4.1.04,12]dodeca-1(12),2,7-triene-5,9-diones (3) and the same type of the tricyclic imidazoles 4 were obtained by carbamoylation of 2 with phenyl isocyanate. The reactions of 2, 3, and 4 with amines were further investigated.
Application of On-line Impedance Measurement Using Fast Fourier Transform to Electrochemical Systems
Authors: Osaka Tetsuya , Naoi Katsuhiko
Published: July 2006

An on-line impedance measuring system based on the fast Fourier transform algorithm was constructed by application of only commercially available interfaces and the FORTRAN language available for an OKITAC System 50/10. A modification of the sampling system is effective for reducing two kinds of errors: the aliasing effect is greatly reduced because of the Nyquist frequency being doubled; the leakage effect is diminished because of the truncation interval being adjusted properly. The above modification enables us to acquire high-accuracy data with quite a small number of averagings processed during one measurement, that is, errors may greatly be reduced and the measurement time to get frequency spectra may be made extremely shorter. The modified impedance measurement using the FFT algorithm is applicable to electrochemical systems proceeding not only at a mercury electrode–solution interface but also at a solid electrode–solution interface.
Studies on Salt Hydrate for Latent Heat Storage. I. Crystal Nucleation of Sodium Acetate Trihydrate Catalyzed by Tetrasodium Pyrophosphate Decahydrate
Authors: Wada Takahiro , Yamamoto Ryoichi
Published: July 2006

The effect of tetrasodium pyrophosphate decahydrate (Na4P2O7·10H2O) as a nucleation catalyst for sodium acetate trihydrate (CH3CO2Na·3H2O) is shown. The supercooled melt of 10 g of CH3CO2Na·3H2O recrystallized at about 5 degrees below the melting point only when 0.1 g of Na4P2O7·10H2O was added to it. More than a thousand cycles of alternate heating and cooling through the melting point were carried out in this work. Some observations on nucleation are given and the results are discussed on the basis of crystallographic data.
Some Observations on the Structural Aspects of o-Hydroxythiobenzamide and Its Complexes with Pt(II), Pt(IV), and Au(III)
Authors: Banerjee Karunamay , Raychaudhury Shyamal
Published: July 2006

1H NMR, electronic spectra, electrical conductivity studies in solution and IR study in solid phase have been done on o-hydroxythiobenzamide and its complexes with Pt(II), Pt(IV), and Au(III). The results indicate presence of the thioamide-thioimidic acid equilibrium in o-hydroxythiobenzamide, the thioamide form in the Pt(II) and Pt(IV) complexes, the thioimidate form in the Au(III) complex and free phenolic OH group in the Pt(IV) and Au(III) complexes.
Volume Profile for the Aquation Reactions of trans- and cis-[Co(en)2NO2Cl]+, cis-[Co(bpy)2NO2Cl]+, cis-[Co(bpy)2NO2Br]+, and cis-[Co(phen)2NO2Br]+
Authors: Kitamura Yoichi
Published: July 2006

The activation volume at normal pressure (ΔV\eweq) and the reaction volume (ΔV) are obtained for five aquation reactions of the Co(III) complex ion. The results are [given as the complex ion, ΔV\eweq/cm3 mol−1 (t/°C), ΔV/cm3 mol−1 (t/°C)]: trans-[Co(en)2NO2Cl]+, 0.1 (15), −10.4(15); cis-[Co(en)2NO2Cl]+, 0.9 (30), −9.3 (25); cis-[Co(bpy)2NO2Cl]+, 2.9 (30), −9.1 (25); cis-[Co(bpy)2NO2Br]+, 11.3 (30), −6.7 (25); cis-[Co(phen)2NO2Br]+, 3.3 (35), −12.5 (30). These magnitudes of ΔV\eweq are interpreted as resulting from the counterbalance of the volume increase attributable to the dissociation of the leaving ligand and the volume decrease due to the partial incorporation of one water molecule in the activated complex.
Conformational Analysis of Intramolecular Excimer Formation in Dinaphthylalkanes
Authors: Ito Shinzaburo , Yamamoto Masahide , Nishijima Yasunori
Published: July 2006

Intramolecular excimer formation processes were explained by the conformational energy calculated by an empirical method. Observed rate constants of excimer formation processes are closely correlated to the fraction of tg conformation. This indicates that intramolecular excimers are mainly formed by the internal rotation, trans→gauche, with reference to the naphthalene unit. The fraction of the tg conformation, which is an adjacent conformation to the excimer conformation on the conformational energy map, serves as an effective concentration of the intramolecular reaction. The small formation rate for rac-2,4-di(2-naphthyl)pentane is due to the unfavorable rotational mode (g+\ightleftarrowsg−) required to take the excimer conformation.
The CNDO/S-CI Calculations of the Singlet nπ* and ππ* Levels of Quinones
Authors: Kuboyama Akira , Kozima Yoshikuni , Maeda Junzo
Published: July 2006

The calculations proved to reproduce well the observed S1 nπ* levels of quinones, the numbers of the singly excited configurations contained in CI being twice those of the basis AO’s. The calculations taking 0.500 as the κ value reproduce well the observed singlet ππ* levels also. The unknown S1 nπ* levels of some quinones were predicted on the basis of the calculated results.
The Photoreduction of Viologen Dyes with Palladium meso-Tetraphenylporphyrintrisulfonate
Authors: Okura Ichiro , Aono Shigetoshi , Takeuchi Makoto , Kusunoki Shin
Published: July 2006

Pd–TPPS3 was found to be an effective photosensitizer for the photoreduction of viologen dyes, such as methyl, ethyl, propyl, butyl, and heptyl viologens. The order of the reduction rate was as follows: Ethyl>Butyl>Methyl>Propyl>Heptyl. The respective complex formation was observed between Pd–TPPS3 and viologen dyes, and electron transfer from photoexcited Pd–TPPS3 to viologen dye was discussed.
Thermal cis-trans Isomerization of (CH)x and (CD)x
Authors: Tanaka Masashi , Yasuda Hajime , Tanaka Jiro
Published: July 2006

Thermal cis-trans isomerization of poly(acetylene), (CH)x, and poly(acetylene-d2), (CD)x, is investigated by visible spectroscopy over the temperature range 90–150 °C. The reaction does not obey simple kinetics. The initial time activation energy for the cis-trans isomerization is 11 kcal/mol for (CH)x and 16 kcal/mol for (CD)x.
Mechanochemical Reactions at High Pressures. IV. Transformation of Lead Monoxide
Authors: Okuri Yasuhiro , Ogo Yoshiaki
Published: July 2006

The mechanochemical phase transformation of lead monoxide has been studied by the X-ray diffraction method. It is established that the transformation of lead monoxide proceeds by a stress-induced martensitic mechanism.
Mass-spectrometric Measurements of Enthalpy and Entropy Changes for the Mixed Dimer Reaction: Na2Cl2(g)+K2Cl2(g)=2NaKCl2(g)
Authors: Sasamoto Tadashi , Itoh Mitsuru , Sata Toshiyuki
Published: July 2006

The enthalpy(ΔHr°) and entropy(ΔSr°) changes for the mixed dimer formation reaction, Na2Cl2+K2Cl2=2NaKCl2, have been measured by mass-spectrometry in the temperature range of 793 to 1083 K. ΔHr°=−1.67 kJ mol−1 and ΔSr°=5.69 J K−1 mol−1 were obtained. These very small values were referred both to the mainly ionicbonding structure in the related dimers and to preserving the isobonding through the reaction.
Kinetics of Structural Rearrangement Accompanying the Substitution Reaction on Complex [Co(terpy)(hmpa)3]2+(terpy=2,2′: 6′,2″-Terpyridine) in Hexamethylphosphoric Triamide
Authors: Abe Yuriko , Wada Goro
Published: July 2006

The reaction of structural rearrangement accompanying the substitution of hexamethylphosphoric triamide (HMPA) for 2,2′: 6′,2″-terpyridine (terpy) from octahedral [Co(terpy)(hmpa)3]2+ to tetrahedral [Co(hmpa)4]2+ proceeds through a five-coordinated intermediate in HMPA. The following values for the first-order rate constant at 25 °C, ΔHd\eweq, and ΔSd\eweq were obtained: kd=3.55×10−5 s−1, ΔHd\eweq=105.4 kJ mol−1 and ΔSd\eweq=+15.9 J K−1 mol−1.
Determination of Titanium(IV) Using o-Hydroxyhydroquinonephthalein and Tween 20
Authors: Mori Itsuo , Fujita Yoshikazu , Sakaguchi Kimiko
Published: July 2006

A new, simple and sensitive spectrophotometric method for the determination of titanium(IV) was studied using o-hydroxyhydroquinonephthalein(Qn.Ph.) and Tween 20. The analytical species of interest have an absorption maximum at 595 nm and obeyed Beer’s law over the range 0.3–2.4 μg of titanium(IV) in final 10 ml solution. This method was highly sensitive in comparison with Sandell sensitivity of 0.00025 μ/cm2 for titanium(IV) at an absorbance of 0.001 at 595 nm against water and the molecular extinction coefficient of the Qn.Ph.–titanium (IV) complex was 1.91×105 l mol−1 cm−1.
Geometrical Isomerization of μ-Peroxo-bis[diethylenetriamine-(R)-propylenediaminecobalt(III)] Ions via Labile Cobalt(II) Species
Authors: Sasaki Yoichi , Tachibana Masahiko , Saito Kazuo
Published: July 2006

The title complex ion undergoes slow geometrical isomerization. A mechanism involving labile cobalt(II) species which is in equilibrium with the title ion, is suggested.
Studies on Some Azine Complexes of Lanthanum(III) and Samarium(III)
Authors: Mital Satya Prakash , Singh Ranvir V , Tandon Jagdish Prasad
Published: July 2006

Pentacoordinated lanthanum(III) and samarium(III) complexes of salicylaldehydeazine and 2-hydroxy-1-naphthaldehydeazine have been synthesized and characterized by elemental analysis, molecular weight determinations, conductance, and magnetic measurements as well as infrared, ultraviolet spectral, and X-ray powder diffraction studies. Their pyrolytic behaviour has also been discussed.
The Favorskii-type Rearrangement of 3-Bromo-β-ionone with Sodium Ethoxide
Authors: Nanasawa Masato , Kamogawa Hiroyoshi
Published: July 2006

The reaction of 3-bromo-β-ionone with sodium ethoxide afforded ethyl 4-(2,6,6-trimethyl-2-cyclohexenylidene)butyrate by a Favorskii-type rearrangement, accompanied by double-bond migration, while with sodium phenoxide or diethyl amine, substitution products were primarily obtained.
A Synthetic Route to (±)-Tetrahydroanhydroaucubigenone
Authors: Kimura Hiroshi , Obara Heitaro , Takahashi Sei
Published: July 2006

(±)-Tetrahydroanhydroaucubigenone was synthesized by partial reduction, followed by acid hydrolysis, of (4aRS,7RS,7aSR)-7-(methoxycarbonyl) octahydrocyclopenta[c]pyran-1,5-dione ethylene acetal, which was prepared from 2,3,4-tris(ethoxycarbonyl)cyclopentanone through 7 steps.
The Revised Structure of Furcation, a Component of Leaves of Viburnum furcatum Blume
Authors: Hase Tsunao , Iwagawa Tetsuo
Published: July 2006

The structure of furcatin, which was proposed to be p-vinylphenyl 6-O-apiosyl-(1→6)-β-d-glucoside, was revised to p-allylphenyl 6-O-[3-C-(hydroxymethyl)-β-d-erythrofuranosyl]-(1→6)-β-d-glucopyranoside by spectral and chemical results.
Stereoselective Synthesis of Mixed Acetal Glycosides by Reaction of Tri-O-acetyl-N-(2,4-dinitrophenyl)-α-d-glucosaminyl Bromide with Alcohol in Acetone1
Authors: Koto Shinkiti , Inada Shigeru , Narita Tomoko , Morishima Naohiko , Zen Shonosuke
Published: July 2006

Some mixed acetal glycosides were stereoselectively synthesized by the reaction of 3,4,6-tri-O-acetyl-2-deoxy-2 -(2,4-dinitroanilino)-α-d-glucopyranosyl bromide with alcohols in acetone containing Hg(CN)2, HgBr2, and tetrabutylammonium bromide at room temperature. When t-butyl alcohol was used, a novel enol glycoside of acetone was formed.
Stereospecific Reductive Desulfinylation of 1-Aryl-2-(methylsulfinyl)-2-(methylthio)ethenes with Grignard Reagents
Authors: Ogura Katsuyuki , Arai Kazutaka , Tsuchihashi Gen-ichi
Published: July 2006

(E)-1-Aryl-2-(methylsulfinyl)-2-(methylthio)ethene, obtained by the Knoevenagel-type condensation of methyl (methylthio) methyl sulfoxide with the corresponding aromatic aldehyde, was found to react with ethylmagnesium chloride to give (Z)-1-aryl-2-(methylthio)ethene predominantly. Since the reaction of (Z)-1-(methylsulfinyl)-1-(methylthio)-2-phenylethene afforded (E)-1-(methylthio)-2-phenylethene, the present reaction appeared to be stereospecific.
CuCl-catalyzed Oxidative Coupling Reaction of Secondary Amines with Molecular Oxygen in Pyridine
Authors: Kajimoto Tsunesuke , Takahashi Hidetaka , Tsuji Jiro
Published: July 2006

Oxidation of diphenylamine with molecular oxygen in the presence of CuCl in pyridine at room temperature to give tetraphenylhydrazine in a high yield was achieved by selecting suitable reaction conditions. N-methylaniline was also oxidized to give N,N′-dimethyl-N,N′-diphenylhydrazine.
Aminolysis of Activated Esters Formed by Reaction of Carboxylate Salts with Strained Phosphonates and Phosphinates
Authors: Acher Francine , Wakselman Michel
Published: July 2006

Nucleophilic attack of a carboxylate salt on a five-membered phosphonic or phosphinic ester followed by an intramolecular acyl transfer reaction gives a substituted aryl ester. Due to the intramolecular base catalysis of a neighbouring P=O group the bimolecular aminolysis of this ester is a fast process.
Liquid Crystal Formation in Binary Systems. VII. Liquid Crystals Induced in N-[4-(Dimethylamino)benzylidene]-4-alkoxyaniline-4,4′-Dinitrobiphenyl and Related Systems
Authors: Fukui Minoru , Matsunaga Yoshio
Published: July 2006

By the addition of 4,4′-dinitrobiphenyl to nonmesogenic 4-(dimethylamino)-4-alkoxy derivatives of N-benzylideneaniline, smectic liquid crystals could be induced. This dinitro compound induces liquid crystals more pronouncedly than N-(4-nitrobenzylidene)-4-nitroaniline and 4,4′-dinitroazoxybenzene do when the alkoxyl group in the donor molecule is methoxyl or ethoxyl, while it induces less pronouncedly when the alkoxyl group is propoxyl. 4,4′-Dicyanobiphenyl gives a metastable nematic liquid crystal when it is mixed with N-[4-(dimethylamino)benzylidene]-4-propoxyaniline and a metastable smectic liquid crystal with N-(4-propoxybenzylidene)-4-(dimethylamino)aniline. Moreover, liquid crystals are formed in the binary systems of N,N,N′,N′-tetramethylbenzidine with 4-nitro-4-alkoxy derivatives of N-benzylideneaniline. They are metastable but cover rather wide composition ranges. The examination of the layer spacing of the smectic A phase revealed that the induced phase is a monolayer liquid crystal.
The Macromolecular Ion Flotation of Fe3+, Cu2+, and Ni2+ by the Use of Charcoal and Cationic Surfactant
Authors: Sasaki Tsunetaka , Mochizuki K\={o}ji , Ishiwata Satoshi
Published: July 2006

The macromolecular ion flotation of Fe3+, Cu2+, and Ni2+ ions by the combined use of charcoal and hexadecyltrimethylammonium chloride (HTAC) was studied. The flotation of powdered active charcoal itself was first studied; a 100% floatability was obtained for the flotation of 2500 ppm charcoal by the addition of 6 ppm of polyacrylamide and 550 ppm of HTAC in the pH range from 4 to 13. For the studies of the flotation of Fe3+, Cu2+, and Ni2+ ions, diagrams of the floatability of the respective ions vs. the composition of charcoal and HTAC, and the floatability of the respective ions vs. the pH at a constant composition of charcoal and HTAC, were constructed. A nearly 100% floatability was obtained for Fe3+, Cu2+, and Ni2+ ions at pH values larger than 4.5, 9.5, and 11 respectively. This order is the same as that of the solubility products of Fe(OH)3, Cu(OH)2, and Ni(OH)2. It was confirmed that Fe3+ ions are adsorbed as hydroxides on charcoal; they are subsequently floated over the whole range of pH values combined with charcoal, while the Cu2+ and Ni2+ ions are adsorbed as simple ions on charcoal and floated in the lower pH region. They are adsorbed as hydroxide on charcoal and floated in a higher pH region.
Dual Fluorescence of Pyrazine Cooled in a Supersonic Free Jet
Authors: Mikami Naohiko , Igarashi Hisao , Kaya Koji , Ito Mitsuo
Published: July 2006

The fluorescence excitation spectrum of the lowest excited 1B3u(n π*) state of pyrazine cooled in a pulsed supersonic free jet was observed. The fluorescence decay of the isolated molecule was also measured in the free jet. The rotationally cooled pyrazine in the collision free condition exhibits extremely large fluorescence quantum yield and dominant slow fluorescence component for low lying vibronic levels. The ratio of the pre-exponential factors of the dual fluorescence decay was examined in terms of the available theory of singlet-triplet mixed state model. It was found that the number of coupled triplet levels obtained from the observed ratio is inconsistent with the calculated excess energy dependence of vibronic density in the triplet state. Remarkable rotational level dependence of the ratio of the pre-exponential factors was observed for the electronic origin, while such a rotational dependence was not found for the lifetime of the slow fluorescence.