bluuebunny/crossref_metadata_2025 huggingface dataset:
Conditions of the Formation of Rare Earth Phosphates and the Colors of Their Powders
Authors: Tsuhako Mitsutomo , Ikeuchi Sayuri , Matsuo Tsuneo , Motooka Itaru , Kobayashi Masamitsu
Published: July 2006

Rare earth oxides, such as La2O3, Pr6O11, Nd2O3, and Sm2O3, can react with phosphoric acid to give four kinds of rare earth phosphates (orthophosphates LnPO4·0.5H2O and LnPO4, catena-polyphosphates Ln(PO3)3 and ultraphosphates LnP5O14), while in the reaction of CeO2 with phosphoric acid there are formed five kinds of phosphates (orthophosphate CePO4, pyrophosphate CeP2O7, two types of catena-polyphosphate Ce(PO3)3 and Ce(PO3)4, and ultraphosphate CeP5O14). The formation of these products in the CeO2–H3PO4 system are notably different from these in other systems, showing that cerium(III) phosphates as well as cerium(IV) phosphates can exist stably. It can be seen from the X-ray diffraction patterns that each corresponding phosphate (ortho, catena-Qoly, and ultraphosphates) of lanthanum, cerium(III), praseodymium, neodymium, and samarium is isomorphous. This may be caused by the facts that the valencies of all these metals are +3 and that their ionic radii are almost equal to one another (La(III) 1.06 Å–Sm(III) 0.96 Å). The conditions of the formation of each phosphate were investigated, and the colors of the crystals, the densities, and the infrared absorption spectra of various rare earth phosphates were also examined.
Rate of Ligand Exchange of Tris(acetylacetonato)iron(III) with 2-Thenoyltrifluoroacetone in Organic Solvents
Authors: Sekine Tatsuya , Honda Hiroshi , Kokiso Masakazu , Tosaka Teruyuki
Published: July 2006

The rate of exchange of acetylacetonate ions (acac−) in tris(acetylacetonato)iron(III) with 2-thenoyltrifluoro-acetonate ions (tta−) has been measured in several organic solvents. The rate was independent of the concentration of Hacac and Htta and nearly the same in carbon tetrachloride, benzene, acetone, and 4-methyl-2-pentanone. However, the rate was much greater in ethanol. The rate of exchange in carbon tetrachloride, benzene, and acetone was found to be enhanced by water, ethanol, and several acids. The enhancement was smaller in acetone than in nonpolar solvents and the stronger the acid, the greater the catalytic effect. The rate controlling step of the exchange reaction was the rupture of an acetylacetonate ion from iron(III) in the complex. These observations have been discussed and possible mechanisms proposed.
Differential Pulse Polarographic Determination of Tellurium by Use of Maximum Wave
Authors: Hasebe Kiyoshi
Published: July 2006

A differential pulse polarographic method for the rapid and simple determination of tellurium by use of maximum wave has been studied. Differential pulse polarographic (DP) peak of tellurium(IV) in 1 mol dm−3 phosphoric acid is observed in the potential range −0.7–−1.0 V vs. SCE. The peak current is very large in comparison with that in d.c. mode, or in normal pulse mode, being proportional to the concentration of tellurium(IV) between 10−8 and 10−7 mol dm−3 contents. The relative standard deviation for 3.94×10−8 mol dm−3 tellurium(IV) under representative sets of good conditions was 0.0342. The method has been applied to the determination of tellurium in carbon steel.
Structure of 5-Hydroxy-2-hydroxymethyl-4-pyridones
Authors: Imafuku Kimiaki , Ishizaka Makoto , Matsumura Hisashi
Published: July 2006

5-Hydroxy-2-hydroxymethyl-4-pyridone and its N-methyl, N-ethyl, and N-phenyl derivatives were prepared from kojic acid. The UV spectra in neutral, acid, and alkaline solutions showed that the neutral species and the conjugate acids existed in the pyridone and the pyridine form, respectively. The conjugate bases may exist in both forms. The acid dissociation constants and the halochromism have been measured and discussed.
On the Behavior of Sulfonyl Imide as a Reactive Intermediate. The Reaction with Enamines
Authors: Nagai Toshikazu , Shingaki Tadao , Inagaki Masao , Ohshima Tetsuya
Published: July 2006

The reactions of N-alkylsulfamoyl chloride with enamines in the presence of triethylamine showed the presence of N-alkylsulfonyl imide (RN=SO2) as a reaction intermediate to give either acyclic (sulfonamides) or cyclic products (1,2-thiazetidine 1,1-dioxides), depending upon the enamines used. The enamines leading to the acyclic products possess either a methylene group on the α-carbon or a hydrogen on the β-carbon of the enamine; the enamine leading to the cyclic product has no such available hydrogen atom. It is thought that the products are formed via a zwitter ionic intermediate provided by the electrophilic attack of the sulfonyl imide sulfur atom on the β-carbon atom of the enamine.
The Beckmann Rearrangement in Concentrated Sulfuric Acid. Studies by Means of NMR and Kinetic Isotope Effect
Authors: Kim Seung-Geon , Kawakami Takeo , Ando Takashi , Yukawa Yasuhide
Published: July 2006

The mechanism of the Beckmann rearrangement of acetophenone (a) and 1-phenyl-2-propanone (b) oximes in concd sulfuric acid was elucidated by means of NMR spectroscopy and the carbon-14 kinetic isotope effect. For (a), the postulated reactive species acetophenone oxime hydrogensulfate was detected, the absence of hydrolysis of the oxime during the course of the reaction being verified. Positive carbon-14 kinetic isotope effect at the phenyl-1, k12/k14=1.026 at 40 °C and 1.019±0.005 at 60 °C, confirmed a definite change in bonding of the phenyl-1 carbon in the transition state of the reaction. Concertedness of the rearrangement was thus established. For (b), sulfonation of the benzene ring prior to the rearrangement was observed, kinetic isotope effect study being found to be useless.
An ESR Study of Polysubstituted N-Aryl-N-(arylthio)aminyls
Authors: Miura Yozo , Katsura Yosuke , Kinoshita Masayoshi
Published: July 2006

An ESR spectroscopic investigation of N-(2,4,6-trimethyl-, trimethoxy-, triisopropyl-, and tri-t-butylphenyl)N-(aiylthio)aminyls (2), Ar\dotNSAr′, is described. The aminyls are generated from the corresponding N-arylarenesulfenamides, ArNHSAr′, by hydrogen-abstraction, the aN values of which are 9.10–12.30 G and the g-values 2.0056–2.0067. On the basis of the ESR parameters the conformations for 2 have been discussed. Decay kinetic studies on 2 were conducted in benzene, and 2 were found to be persistent aminyls—particularly the t-butylsubstituted aminyl, N-(2,4,6-tri-t-butylphenyl)-N-(4-nitrophenylthio)aminyl.
Reactions of 2-Chlorothiophene with Cation Exchange Resin and 100% Orthophosphoric Acid. Formation of the Dimer Type Products Containing a Tetrahydro-2-thiophenone Moiety
Authors: Sone Tyo , Shiromaru Osamu , Igarashi Shin-ichi , Kato Eiichi , Sawara Mutsuo
Published: July 2006

It has been found that 2-chlorothiophene is converted into the dimer type products by Amberlyst 15 or 100% orthophosphoric acid, the reaction yielding 4- and 5-(5-chloro-2-thienyl)tetrahydro-2-thiophenones and 4-(2-thienyl)-2(5H)-thiophenone together with 5-chloro-2,2′-bithienyl. The distribution of the products is considerably affected by the acid used and in the presence of phenol or anisole the reaction affords additionally 4-[5-(p-hydroxyphenyl)-2-thienyl] tetrahydro-2-thiophenone or 4-[5-(p-methoxyphenyl)-2-thienyl] tetrahydro-2-thiophenone, respectively.
An Improved Synthesis of 3′,4′-Dideoxykanamycin B
Authors: Yoneta Toshio , Shibahara Seiji , Matsuno Tomio , Tohma Susumu , Fukatsu Shuzo , Seki Shigeo , Umezawa Hamao
Published: July 2006

A new synthetic route has been exploited for the large scale production of 3′,4′-dideoxykanamycin B starting with kanamycin B. The key stage in the synthesis involves the formation in excellent yield of the 3′,4′-anhydro-4′-epi derivative (5) followed by convertion to the 3′-ene derivative through the iodohydrin. Compound 5 was prepared by the treatment of 3′,2″-di-O-benzoyl-4″,6″-O-cyclohexylidene-4′-O-methylsulfonyl-penta-N-t-butoxycarbonyl-kanamycin B with sodium methoxide.
Odor and Volatile Compounds in Liquid Swine Manure. III. Volatile and Odorous Components in Anaerobically or Aerobically Digested Liquid Swine Manure
Authors: Yasuhara Akio , Fuwa Keiichiro
Published: July 2006

Volatile and odorous components were isolated from anaerobically or aerobically digested liquid swine manure by direct solvent-extraction and flash-distillation under reduced pressure. The concentrations of indole, oxindole, dimethylsulfoxide, phenol, and a few carboxylic acids increased, and o-aminoacetophenone decreased during digestion. Alkaline components were not so important for the odor. Offensive odor was formed by mixing phenols and carboxylic acids. Complete aeration resulted in a remarkable decrease of lower carboxylic acids.
New C31 Secodammarane-type Triterpenoids, Alnuseric Acid and Alniselide, in the Male Flowers of Alnus serrulatoides
Authors: Suga Takayuki , Hirata Toshifumi
Published: July 2006

Two novel C31 3,4-secodammarane-type triterpenoids, alnuseric acid and alnuselide, were isolated from the male flowers of Alnus serrulatoides Call. (Betulaceae); their structures were elucidated to be (20S,24R)-20,24-epoxy-24-methyl-3,4-secodammar-4(28)-en-3-oic acid and (11R,2OS,24R)-20,24-epoxy-24-methyl-3,4-secodammar-4(28)-en-3,11α-olactone, respectively, by a combination of chemical and spectroscopic methods.
Pseudo-sugars. 3. Alternative Synthesis of Penta-N,O-acetyl-Dl-validamine and Its Analogs
Authors: Ogawa Seiichiro , Kasahara Isamu , Suami Tetsuo
Published: July 2006

Dl-Validamine and its amino deoxy and deoxy analogs were synthesized as the acetyl derivatives from endo-7-oxabicyclo[2.2.1]hept-5-ene-2-carboxylic acid, the Diels-Alder adduct of acrylic acid and furan.
14N Nuclear Quadrupole Relaxation Near the Plastic Transition Point in the Low-temperature Phase of 1,4-Diazabicyclo[2.2.2]octane
Authors: Negita Hisao , Maekawa Michio , Kubo Tsuneo , Okuda Tsutomu
Published: July 2006

The relaxation mechanism near the plastic transition in the low-temperature phase of 1,4-diazabicyclo[2.2.2]octane is attributed to the overall molecular tumbling. The activation energy is 23.0 kJ mol−1, which is nearly equal to the value of 22.2 kJ mol−1 in the proton NMR in the plastic phase.
The Dimorphism and Spectral Properties of 4-Anilino-1,2-naphthoquinones
Authors: Matsunaga Yoshio , Miyajima Nobuhiko
Published: July 2006

On the basis of vibrational spectra, especially in the region from 3050 to 3350 cm−1, solid 4-anilino-1,2-naphthoquinones carrying substituents on the phenyl ring are classified into two groups. The p-methyl and p-ethyl derivatives are dimorphic and can be members of both the groups.
Formation of Vaterite by the Reaction of Calcium Methoxide with Aqueous Sodium Carbonate Solution
Authors: Yamaguchi Osamu , Takashita Noriyuki , Shimizu Kiyoshi
Published: July 2006

A mixture of vaterite and calcite was formed by the reaction of calcium methoxide with aqueous sodium carbonate solutions. The reaction temperature was found to be a dominant factor for the formation of vaterite. The kinetics of the transformation of vaterite into calcite was studied.
Studies on 1,2,4-Thiadiazolidine Derivatives. IV. The Isomers of 2,4-Disubstituted 3,5-(Disubstituted imino)1,2,4-thiadiazolidines
Authors: Kinoshita Takeshi , Sato Sadao , Tamura Chihiro
Published: July 2006

Several 2-alkyl-5-alkylimino-4-aryl-3-arylimino-1,2,4-thiadiazolidines and 4-alkyl-5-alkylimino-2-aryl-3-arylimino-1,2,4-thiadiazolidines were synthesized by the oxidation of 1-alkyl-3-arylthioureas with benzoyl peroxide along with 2,4-dialkyl-3,5-bis(arylimino)-1,2,4-thiadiazolidines.
Liquid Phase Peptide Synthesis by the Fragment Condensation on Soluble Polymer Support. II. The Azide Method
Authors: Narita Mitsuaki
Published: July 2006

Fragment condensation on a soluble polymer support by the azide method gave rise to the efficient coupling (94–99% yield) of an N-protected tetrapeptide azide with the amino acid anchored to the soluble polymer support. Bulkiness of amino acid residues on the polymer support did not affect the reactivity toward the peptide azide.
Photolyses of Azidotriazines in Organic Nitro Compounds
Authors: Goka Tsuruji , Hashida Yoji , Matsui Kohji
Published: July 2006

Triazinylnitrenes were found to be inert towards nitro compounds. They afforded the products derived from the combination of two molecules of the starting materials.
ESR Spectrum of Bis(dibenzoylmethanato)oxovanadium(IV) Dissolved in Molten and Crystalline Charge Transfer Complexes
Authors: Araya Kotaro , Matsunaga Yoshio , Ochi Eiji
Published: July 2006

The ESR spectrum of bis(dibenzoylmethanato)oxovanadium(IV) dissolved in a number of pyrene and fluoranthene complexes with aromatic polynitro compounds just above their melting points indicates that the motion of the spin probe is more or less restricted. In some favorable cases, the high effective viscosity of the melts can be partially attributed to the association of the electron donor and acceptor molecules. No abrupt change in the ESR spectral pattern is noted upon solidification and the motion of the probe gradually ceases upon lowering the temperature. Therefore, the lattice appears to be not rigid in these crystalline complexes. On the other hand, the ESR spectrum observed in the molten naphthalene-dinitrophenol complex is not far from isotropic at the melting point. Because of the segregation of the probe upon solidification, the measurements on this solid complex could not be made.
Nuclear Magnetic Resonance Studies of the Cu-chlorophyllin Complex with Flavine Mononucleotide
Authors: Enmanji Koe
Published: July 2006

The NMR relaxation time of the Cu-chlorophyllin (Cu-chln)–flavine mononucleotide (FMN) complex was measured, and its geometrical structure was proposed. The complex has an absorption band at 700 nm which is attributed to complex formation by analogy with the chlorophyll a–FMN complex. Its binding constant is 330 l/mol at 25 °C; this value is larger than those of other Cu-chln complexes. From the analysis of its ESR data, it is clear that the greater part of the electron spin in Cu-chln is distributed on the Gu2+ ion. The distance between the nuclear and electron spins was calculated by measuring the spin-lattice relaxation times. From these results, the distance between the porphyrin ring and the isoalloxazine ring in the Cu-chln-FMN complex molecule is found to be 4.2 Å if the two rings are parallel to each other. The chlorophyll a-FMN complex is assumed to have a similar geometrical structure.
Disintegration of Sulfonated Poly(1,4-piperazinediylterephthaloyl)Microcapsules by Poly(diallyldimethylammonium chloride)
Authors: Suzuki Shiro , Kondo Tamotsu
Published: July 2006

Partially sulfonated poly(1,4-piperazinediylterephthaloyl) microcapsules were found to undergo disintegration by the action of poly(diallyldimethylammonium) ions if the polycation concentration exceeded a certain value. The polycation concentration at which disintegration started was dependent on the degree of sulfonation of the microcapsules and pH of the medium. Exact electrical equivalence of the polyions involved was shown to be a necessary condition for disintegration of the microcapsules to take place. Disintegration of the microcapsules resulted in a formation of coacervate-like liquid drops. This formation of coacervate-like liquid was accelerated by mechanical and thermal agitation. Crosslinking among the polymers constituting the microcapsules prevented disintegration from occurring.
Studies of Inorganic Ion Exchangers. III. Ion Exchange Properties of Ti(HPO4)2·0–1/2H2O to Alkali Metal and Ammonium Ions
Authors: Kobayashi Etsuro
Published: July 2006

In order to develop an inorganic ion exchanger for industrial use, the ion exchange behaviour of Ti(HPO4)2·0–1/2H2O with alkali metal and ammonium ions has been investigated. The ion exchange capacities of Ti(HPO4)2·1/2H2O (hemihydrate) have been determined by forward and backward titration. The saturation ion exchange capacities (QA) of the hemihydrate to Li, Na, K, Cs, and NH4 (M) ions by the forward titration method were 1.9, 3.2, 4.1, 2.5, and 3.7 meq/g at pH 4.5, respectively. The ion exchange capacities (Q°) of the hemihydrate from 0.1 M MCl were 0.31, 1.84, 2.31, 0.21, and 1.01 meq/g to each of the ions. The selectivity quotients (KHM) estimated from the QA and Q° were 0.028, 3.77, 15.7 0.008, and 0.255 to each of the ions, and the selectivities of the hemihydrate increased in the order Cs+<Li+<NH4+<Na+<K+. The empirical formula of the 50% ion exchange products derived from the hemihydrate may be represented by TiMH(PO4)2·0–1/2H2O, (where, M=Na, K, and NH4). The ion exchange of Li and Cs ions did not take place completely however to give a 50% ion exchanger, and the hemihydrate was then converted into a non-stoichiometric compound.
Kinetic Studies of the Electron Transfer Reaction in Iron(II) and Iron(III) Systems. VIII. The Effect of Hexamethylphosphoric Triamide on the Electron Transfer Reaction in Aqueous Solution
Authors: Wada Goro , Nakago Sayuri , Abe Yuriko
Published: July 2006

The kinetics and mechanism of the electron transfer reaction between Fe(II) and Fe(III) in mixed solvents of water and hexamethylphosphoric triamide (HMPA) were studied. The apparent rate constant k varies depending upon [HMPA] and [H+]; k exhibits a minimum value at [HMPA]=1.5 M at constant [H+] and increases linearly with respect to [H+]−1 at constant [HMPA]. Judging from the basicity constant of HMPA, the complex formation constant of Fe(hmpa)3+, and the absorption spectra of aqueous solutions containing Fe(II), Fe(III), HMPA, and HClO4, the existing species in the reaction systems are mostly Fe2+aq, Fe3+aq, Fe(OH)2+, Fe(hmpa)3+, and Fe(hmpa)(OH)2+ at low concentrations of HMPA. Therefore, the probable reaction paths are Fe2+–Fe3+, (k0); Fe2+–Fe(OH)2+, (kH); Fe2+–Fe(hmpa)3+, (kL); and Fe2+–Fe(hmpa)(OH)2+, (kHL) at the concentration range of [HMPA]=0–1 M and [HClO4]=0.03–0.2 M. The occurrence of a minimum value of kvs. [HMPA] is reasonably understood by taking the complex formation between Fe(III) and HMPA into account in reaction rate equation. If the hydrolysis constants of both Fe(OH)2+ and Fe(hmpa)(OH)2+ are considered to be nearly of the same order, the value of kH are approximately ten times larger than that of kHL. At higher concentrations of HMPA, the higher Fe(III)-complexes with HMPA might take part in the electron transfer reaction.
Synthetic Inorganic Ion-exchange Materials. XX. Ion-exchange Properties of Crystalline Antimonic(V) Acid with Alkaline Earth Metal Ions
Authors: Abe Mitsuo
Published: July 2006

A stoichiometrical ion-exchange was observed for all the systems of Mg2+, Ca2+, Sr2+, and Ba2+ with H+ in the crystalline antimonic(V) acid as a cation exchanger. The selectivity sequence, Mg2+<Ba2+<Sr2+<Ca2+, has been found for the ion-exchange reactions in 0.1 M nitrate salt solutions of different alkaline earth metals. Breakthrough and further elution studies were carried out in order to test the reversibility of the ion-exchange reactions. X-Ray analysis indicates that a solid solution forms for the ion-exchange system of the alkaline earth metal ions in the crystalline antimonic(V) acid.
Synthesis, Absorption and CD Spectra of [Co(amino alcohol)(N)2(O)2]-type Complexes
Authors: Okazaki Kenichi , Shibata Muraji
Published: July 2006

Complexes of the [Co(amOH)(N)2(O)2]-type, where amOH represents 2-aminoethanol or (S)-2-amino-1-propanol and (N)2(O)2 represents (gly)2, (β-ala)2, (ox)(en) or (ox)(NH3)2, have been prepared and characterized on the basis of absorption and PMR spectra. Splitting of the T2g band has been observed in the solution spectra of certain isomers of the [Co(gly)2(eta)], [Co(gly)2(S-pra)], or [Co(β-ala)2(eta)] complex. Using the crystal spectral data of the isomers of [Co(gly)2(eta)], the σ- and π-antibonding parameters for the ligating alcoholate O atom have been estimated and it has been found that each parameter shows a higher value than the corresponding parameters for the other ligating N and O atoms. The CD spectrum, in the T2g region, of fac-[Co(gly)2(eta)] has shown an intense peak at ca. 25000 cm−1, and the vicinal effect curve of each isomer of the [Co(gly)2(S-pra)] complex has shown an intense peak at the same frequency.
Preparation and Stereochemistry of Optical Isomers of the Tris-(3,3′-dimethyl-2,2′-bipyridyl N,N′-dioxide)chromium(III) Complex
Authors: Kanno Hideaki , Kashiwabara Kazuo , Fujita Junnosuke
Published: July 2006

A new ligand, (R)- and (S)-3,3′-dimethyl-2,2′-bipyridyl N,N-dioxide(mbdo) forms three diastereomers(I, II, and III) of [Cr(mbdo)3]3+ by the reaction with [Cr(H2O)6]3+ in water. (I) was assigned to a pair of enantiomers, Δ(RRR) and Λ(SSS), and (II) and (III) to either a diastereomeric pair of Δ(RRS) and Λ(SSR) or Δ(SSR) and Λ(RRS). While the racemic (I) was resolved by SP-Sephadex column chromatography, (II) and (III) isomerized in water to each other (II\ightleftarrowsIII) by exposure to ultraviolet light, were resolved by the reaction of [Cr(H2O)4(R or S)-mbdo]3+ with a stoichiometric amount of (S or R)-mbdo. The circular dichroism spectra of these optically active isomers were measured in aqueous solutions and compared with those of complexes of the [CrO6]-type of known absolute configuration. The optically active free (+)589- and (−)589-mbdo were isolated by decomposing Λ(SSS)- and Λ(RRR)-[Cr(mbdo)3]3+, respectively, with edta4−. The active mbdo is optically stable even in boiling water.
Prefered Orientation and π-Bonding of the Hydroxyl Group in 1,2-Benzocycloalken-3-ols
Authors: Mori Nobuo , Kasuya Shin-ichi , Miyazaki Hitoshi , Takezawa Toshiyuki
Published: July 2006

The various values vOH of 1,2-benzocycloalken-3-ols observed in dilute CCl4 solutions have been explained in terms of the inclination angle of the C–O bond to the plane of the benzene ring (θ) and the conformational isomerism of the OH group with respect to the C–O bond. The vOH shift caused by OH…π bonding is angle-dependent, i.e., 9 cm−1 if θ=50–90°, or 17 cm−1 if θ=38–45°.
S
N2 Reactions in Dipolar Aprotic Solvents. VIII. Chlorine Isotopic Exchange Reaction of (Arylsulfonyl)chloromethanes, (Arylsulfinyl)chloromethanes, and 2-Chloro-1-arylethanones in Acetonitrile. A Role of the Nucleophile-substrate Interaction in the Finkelstein Reaction
Authors: Hayami Jun-ichi , Koyanagi Tohru , Kaji Aritsune
Published: July 2006

Chlorine isotopic exchange reactions of substituted chloromethanes [(arylsulfonyl)chloromethanes (1), (arylsulfinyl)chloromethanes (2), and 2-chloro-1-arylethanones (4)] with tetraethylammonium chloride-36Cl were studied in acetonitrile. This study enabled, for the first time, the accurate rate study of the former two classes of compounds (1 and 2) of extremely low reactivity. Both the large enthalpies of activation and the positive entropies of activation were the characteristics for these two substrates (1-p-NO2 and 2-p-NO2). High reactivity of 2-chloro-1-phenylethanone was substantiated, and was not associated with the significant secondary kinetic deuterium isotope effect. A nucleophile-substrate association that proceeds the reaction was suggested and the possible role of such an interaction was examined in the light of the intermediary of the nucleophile-substrate complex in the Finkelstein reaction.
Trans-esterification Reaction Catalyzed by Alkoxo(triphenylphosphine)copper(I) Complexes
Authors: Kubota Minoru , Yamamoto Takakazu , Yamamoto Akio
Published: July 2006

Alkoxocopper and phenoxocopper complexes ROCu (PPh3)n (PPh3=triphenylphosphine; n=1 for R=n-C3H7 or i-C3H7; n=2 for R=CH3, C2H5, CH2=CHCH2, C6H5CH2, or C6H5) react with esters undergoing exchange of the RO group with carboxylic esters. The alkoxocopper and phenoxocopper complexes are found to be excellent catalysts for the trans-esterification of carboxylic esters, dimethyl carbonate, and trimethyl phosphite with alcohols and phenols. A comparison of the ability of the isopropoxocopper complex as trans-esterification catalyst with that of aluminum isopropoxide and titanium isopropoxide shows the superiority of the isopropoxocopper complex. The rate of trans-esterification between p-nitrophenyl acetate and phenol follows the second-order rate law R=k[p-nitrophenyl acetate][phenol], the activation energy of the reaction being estimated to be 12.4 kcal/mol. A mechanism comprising a nucleophilic attack on the copper-bound carbonyl group of the ester by alcohol is proposed.
A Simple MO Treatment on the Nucleophilic Substitution Reactions of Six-membered Aza-aromatic Compounds
Authors: Hirota Minoru , Masuda Hideyuki , Hamada Yoshiki , Takeuchi Isao
Published: July 2006

Nucleophilic substitution reactions of monoaza- and diaza-naphthalenes and -phenanthrenes were discussed on the basis of an HMO calculation taking the nature of the reagent into consideration. Results were compared with the orientation of some nucleophilic substitution reactions, i.e. Chichibabin amination, phenylation by phenyllithium, and methylation by methylsulfinylmethanide ion. The nature of the reagent was explicitly taken into account as the difference in the coulomb integrals and the reagent-dependent orientation of these reactions were explained theoretically.
Reactions of Spiro[2.6]nona-4,6,8-triene Derivatives with Acids and Bases. Rearrangement to a Heptafulvene Derivative and Formation of Ether Linkage Compounds
Authors: Toda Takashi , Saito Katsuhiro , Mukai Toshio
Published: July 2006

Reaction of dimethyl trans-spiro[2.6]nona-4,6,8-trien-1,2-dicarboxylate with phenyllithium afforded trans-1,2-bis(hydroxydiphenylmethyl)spiro[2.6]nona-4,6,8-triene (2) in a good yield. Spirotriene 2 is very sensitive to acids and gave 8-(2,2-diphenylvinyl) heptafulvene accompanied with a quantitative amount of benzophenone by acid treatments. Although 2 is stable to basic reagents, upon treating with sodium hydride, 2 afforded 11-hydroxydiphenylmethyl-8-oxa-9-diphenyltricyclo[5.4.0.01,10]undeca-2,4-diene, and its double bond isomers. Mechanisms of the above reactions are discussed.
Optical and Magnetic Properties of Solid Cation Radical Salts Derived from Some Aromatic Hydrocarbons
Authors: Iida Yôichi
Published: July 2006

The optical and magnetic properties of solid cation radical salts derived from 9,10-dimethylanthracene and 9,10-dichloroanthracene were explained in terms of one-dimensional Hubbard model composed of equivalent sites of the cation radicals, while those of perylene cation radical salt, in terms of Hubbard model of cation radical dimer.
An INDO-MO Study of Peroxyacetyl Nitrate Formation
Authors: Ohkubo Katsutoshi , Sato Hiroyuki
Published: July 2006

The process of peroxyacetyl nitrate (PAN) formation has been disscussed on the basis of INDO calculations. The acetylperoxy radical (APR) has been found to be more reactive towards nitrogen monoxide than towards nitrogen dioxide. The bond strength of the O–O linkage in CH3C(=O)OONO, however, is weaker than that of PAN or H2O2.
Lifetime Measurement of HO2 Radical
Authors: Tsuchiya Soji , Nakamura Tomiji
Published: July 2006

The formation and dissipation kinetics of HO2 radical was investigated by means of UV absorption measurement in a gas mixture, H2+ca. 1% O2+a trace of Hg vapor which was irradiated by a 253.7 nm light pulse. The rate constant of the reaction 2HO2→H2O2+O2 was determined to be (2.8±0.3)×1012 cm3 mol−1 s−1.
Kinetics of the Substitution of Acetonitrile in (Acetonitrile)chlorobis(triphenylphosphine)rhodium(I) by Triphenylphosphine
Authors: Ohtani Yoshimi , Yamagishi Akihiko , Fujimoto Masatoshi
Published: July 2006

The substitution of coordinated acetonitrile in (acetonitrile)chlorobis(triphenylphosphine)rhodium(I) by triphenylphosphine was studied in benzene by the stopped-flow method under anaerobic conditions. The reaction was found to proceed through both an associative and a dissociative path to yield chlorotris(triphenylphosphine)rhodium(I).
Preparation and Reaction of N-Imidoyliminotriphenylphosphoranes
Authors: Yoshida Hiroshi , Ogata Tsuyoshi , Inokawa Saburo
Published: July 2006

N-Imidoyliminotriphenylphosphoranes 2 have been prepared by the reaction of triphenylphosphine with N-chloroamidines followed by treatment with base. 2 can react readily with hydrochloric acid or methyl iodide to give the corresponding salts. Treatment of 2 with carbon disulfide gave N-(thioacyl)iminotriphenylphosphoranes together with isothiocyanates.
The Formation of 3,4,5-Tris(substituted phenyl)-4,5-dihydro-1,2-oxazole N-Oxides in the Oxidations of (Substituted phenyl)nitromethanide Anions with Silver Nitrate or Peroxodisulfate
Authors: Fukunaga Kimitoshi , Hamanaka Kenji , Kimura Makoto
Published: July 2006

The reaction of an alkali metal salt of (substituted phenyl)nitromethane (1) with silver nitrate or peroxodisulfates in dimethyl sulfoxide (DMSO) gives 3,4,5-tris(substituted phenyl)-4,5-dihydro-1,2-oxazole N-oxides (2) in a good yield.
The Glow-discharge Reactions of Amines
Authors: Asada Hideki , Nomura Masakatsu , Kikkawa Sh\={o}ichi
Published: July 2006

The glow-discharge reactions of propylamine, dipropylamine, and N,N-dimethyl-2-methyl-1-propenylamine were studied. The results show that the primary amines yield RN=CHR′ and RNHCH2CN, and that the secondary amines produce R(R′)NCH(R″)CN. N,N-Dimethyl-2-methyl-1-propenylamine produces a series of imine and nitrile.
New Azulene Derivatives Obtained by the Sulfur Dehydrogenation of Guaiene : 3,6,9-Trimethylazuleno[4,5-b]thiophene and 2-Methylthioguaiazulene
Authors: Kohara Kazuko , Tachibana Hojun , Masuyama Yukio , Otani Yasushi
Published: July 2006

Two new azulene derivatives, 2-methylthioguaiazulene and 3,6,9-trimethylazuleno[4,5-b]thiophene, have been obtained and characterized, along with known 3,5,8-trimethylazuleno[6,5-b]thiophene and 2,2′-biguaiazulenyl, by the sulfur dehydrogenation of guaiene.
The Reaction of Methylferrocene with Manganese(III) Acetate
Authors: Izumi Taeko , Satou Yoshibumi , Yoshida Yoshio , Kasahara Akira
Published: July 2006

The oxidation of methylferrocene with manganese(III) acetate in acetic acid yielded three products which arose from the ferrocenylmethylation of methylferrocene. The reaction of methylferrocene with manganese(III) acetate in presence of styrene was also examined.
A Novel Approach to cis-Jasmone and Dihydrojasmone from 2-(2-Benzothiazolylthio)-2-(3-oxobutyl)oct-5-en(or -an)oic Acid by Electrolytic Procedure
Authors: Torii Sigeru , Tanaka Hideo , Kobayasi Yuichi , Nokami Junzo , Kawata Mikio
Published: July 2006

cis-Jasmone (7a) and dihydrojasmone (7b) have been synthesized by facile five-step processes starting from methyl acetoacetate involving electrolysis procedure. Methyl 2-(2-benzothiazolylthio)oct-5-en(or -an)oate, prepared from methyl 2-acetyloct-5-en(or -an)oate (1) by the reaction with the N-(2-benzothiazolylthio)morpholine, were allowed to react with methyl vinyl ketone, leading to the Michael adducts 4. After hydrolysis of 4, the corresponding acids 5 were electrolyzed to afford the desired 1,4-diketone 6 in 45–48% overall yields (based on 1), whose base-catalyzed cyclization gave 7 smoothly.
The Crystal and Molecular Structure of Perylene–2,5-Dibromo-3,6-dichloro-p-benzoquinone Complex
Authors: Kozawa Kozo , Uchida Tokiko
Published: July 2006

Crystals of the 1 : 1 molecular complex of perylene–2,5-dibromo-3,6-dichloro-p-benzoquinone are triclinic, with a=8.669, b=9.697, c=7.321 Å, α=103.20, β=110.92, γ=64.60°, space group P\bar1, Z=1. The structure has been determined from diffractometer data by the heavy atom method and refined using the full-matrix least-squares method to R 0.069 for 2241 independent reflections. Stacks, with alternating donor and acceptor molecules, extend along the c direction. The acceptor molecule assumes two orientations, with a population ratio 1 : 1. A small degree of correlative change in the C–C bond lengths has been found in the perylene molecule on complex formation. The geometry of the quinonoid skeleton of the acceptor is similar to those of the anils and their complexes.
An Empirical Relation between the Quenching Cross-sections of Metastable Argon and the Molecular Diameter of the Quenchers
Authors: Matsubara Kazuhiro , Oono Yoshitsugu , Kai Shoichi , Nishimura Yukio
Published: July 2006

For polyatomic quenchers there is a fairly accurate linear relation between σQ1⁄2 and r, where σQ is the quenching cross-section of rare gas metastables (especially Ar(3P2)) and r, the effective radius of the quencher.
Thermodynamic Study on the Adsorption of Dioctadecyl Ether at Hexane/Water Interface
Authors: Matubayasi Norihiro , Dohzono Masatake , Aratono Makoto , Motomura Kinsi , Matuura Ryohei
Published: July 2006

The adsorption of dioctadecyl ether was studied at hexane/water interface, as functions of temperature, pressure, and mole fraction of dioctadecyl ether in hexane. The phase transition between expanded and condensed films was observed with decreasing temperature and increasing pressure and concentration. The thermodynamic quantities associated with the adsorption such as entropy, volume, and energy change were evaluated and comparison was made with the adsorbed films of 1-octadecanol at the same interface in which phase transition takes place. It is found that the dioctadecyl ether shows small negative discontinuous changes of the thermodynamic quantities with the transition from the expanded to the condensed films.
Reactions of 4H-1-Benzothiopyran-4-ones and Related Compounds with Dimethyl Sulfate
Authors: Nakazumi Hiroyuki , Kitao Teijiro
Published: July 2006

4H-1-Benzothiopyran-4-ones (thiochromones) and isomeric 2H-1-benzothiopyran-2-ones (thiocoumarins) have been allowed to react with dimethyl sulfate (DMS) to study the differences in reactivity on methylation. Methylation of 2-methyl (thiochromones) with DMS afforded the blue colored dimerization products, 4-(4-methoxy-1-benzothiopyran-2-ylidenemethyl)-2-methyl-1-benzothiopyrylium perchlorates, while that of 7-methoxy-4-methyl(thiocoumarin) gave the O-methylated yellow salt, 2,7-dimethoxy-4-methyl-1-benzothiopyrylium perchlorate. Methylations of oxa analogues (coumarins) and aza analogues (2-quinolones) of thiocoumarins with DMS have also been examined. It has been found that the ease of formation of methylation products is affected by the hetero atom and carbonyl group.
Excited-state Electronic Interaction of m-Aminoacetophenone with Aliphatic Alcohols
Authors: Tanimoto Yoshifumi , Inoue Kenji , Furukawa Yoshihiko , Segawa Yoko , Itoh Michiya
Published: July 2006

The electronic interaction of both ground-state and excited-state m-aminoacetophenone (MAAP) with several aliphatic alcohols in nonpolar viscous solvent was investigated by steady-state and nanosecond fluorescence spectroscopies. Concentration dependence of several alcohols in liquid paraffin-hexane (LPH) mixed solvent upon fluorescence and absorption spectra suggests a complex formation of MAAP with aliphatic alcohols in the ground state. In the typical LPH solution of MAAP containing high concentration of alcohol, the complex fluorescence exhibits two-component decay and a longer wavelength fluorescence than the complex fluorescence exhibits a rise and decay. The results demonstrate that the complex in the excited state further associates with alcohol to make an exciplex including an alcohol molecule.
Wheland Polynomial. I. Graph-theoretical Analysis of the Contribution of the Excited Resonance Structures to the Ground State of Acyclic Polyenes
Authors: Ohkami Noriko , Hosoya Haruo
Published: July 2006

The Wheland polynomials, the set of the numbers, w(G,j), of the j-th excited resonance structures, for a number of acyclic polyenes were calculated. The relations of w(G,j) with the non-adjacent numbers, p(G,k), topological index, ZG, and the total π-electronic energy, Eπ, were analyzed in detail for linear polyenes. For branched polyenes similar results were obtained, and it was found and proved that Eπ is linearly related with the number of Dewar (singly excited)structures. Method for the numbering of atoms to generate the canonical resonance structures was discussed.
X-Ray Molecular Structure of 1-Cyano-7,8-benzo-11-oxatricyclo[4.2.2.12,5]undeca-3,7,9-triene
Authors: Kan Kojiro , Kai Yasushi , Yasuoka Noritake , Kasai Nobutami
Published: July 2006

C15H11ON, M.W. 221.17, monoclinic, space group P21/c, a=9.451(1), b=8.267(1), c=14.336(2) Å, β=94.37(1)°, Dm=1.31, Dc=1.32 g cm−3, Z=4, R=0.088 for 1300 non-zero reflections. The molecule has an endo-configuration, and the furan ring has an envelope form.
Properties and Structure of Alkali Aluminophosphate Glass
Authors: Kishioka Akira
Published: July 2006

Several series of alkali (sodium and potassium) aluminophosphate glasses were prepared with compositions of 32–63 mol % of P2O5 and the properties of these glasses were determined. In the glasses with a higher P2O5 content (P2O5\gtrsim42.5 mol % in the Na2O–Al2O3–P2O5 glass and P2O5\gtrsim45 mol % in the K2O–A12O3–P2O5 glass), the density, refractive index, and chemical resistivity increased with increasing amounts of Al2O3. In the glasses with a lower P2O5 content (P2O5\gtrsim37.5 mol % in the Na2O glass and P2O5≈40 mol % in the K2O glass), however, almost no increase of the density was found by an increase of Al2O3; the increases in the refractive index and chemical resistivity were also smaller than those in the glasses with a higher P2O5 content. The infrared absorption spectra of the glasses varied also with the P2O5 content. These changes in the properties are due to a marked structural difference between the glasses with a higher P2O5 content and those with a lower P2O5 content, and are also associated closely with the structural role of Al3+ ions in the glass.
Phase-transfer Reactions Catalyzed by Phosphoric Triamides Containing Hydrophobic Groups
Authors: Tomoi Masao , Hasegawa Takashi , Ikeda Manabu , Kakiuchi Hiroshi
Published: July 2006

Aqueous organic two-phase reactions (halogen exchange, cyanation, and borohydride reduction) have been catalyzed by phosphoric triamides containing hydrophobic groups. The phosphoric triamides, which have a high cation binding ability, exibited high catalytic activity for the two-phase reactions. The catalytic activity of N-alkylteramethylphosphoric triamides (1) was higher than that of the corresponding pentamethyl derivatives and the difference has been explained in terms of the contribution of the dimeric species of 1 and/or hydrogen bonding between the NH of 1 and the anionic moieties of inorganic reagents.
α,β-Unsaturated Carboxylic Acid Derivatives. XVII. The Facile Synthesis of Ethyl α-Azido-α-alkenoates and Reduction to Ethyl α-Amino-α-alkenoates
Authors: Shin Chung-gi , Yonezawa Yasuchika , Unoki Kazuo , Yoshimura Juji
Published: July 2006

Several pathways leading to ethyl α-azido-α-alkenoates (8) by the β-elimination to ethyl α-azido-β-substituted (hydroxy-, acetoxy-, or mesyloxy)-alkanoates with NaN3 or Et3N have been examined. The optimized procedure, in combination with subsequent reduction provides a general synthetic route to α-amino-α-alkenoic acid esters (9). The configuration of 8 and 9 have been shown to be of (Z)-geometry.
Syntheses of Several Muramyl Peptides in Relation to Chemical Structures of Less Immunoadjuvant Bacterial Cell Walls
Authors: Kusumoto Shoichi , Ikenaka Kazuhiro , Shiba Tetsuo
Published: July 2006

Various structural analogs of N-acetylmuramyl-l-alanyl-d-isoglutamine, which had been shown to be the minimum structure required for the immunoadjuvant activity of bacterial cell walls, were synthesized in order to investigate in more detail the relationship between the activity and chemical structures. Particularly, the compounds of the structures corresponding to the cell walls of special bacteria without immunoadjuvant activity were prepared in this study. Several novel procedures including the preparation of a branched glutamyl peptide were newly exploited to accomplish the syntheses of muramyl peptides with complicated structures. As a result of this synthetic study, new informations were obtained on the structural requirement for the immunoadjucant activity.
Restricted Rotation Involving the Tetrahedral Carbon. XXVI. Certainties and Uncertainties Involved in the Rates of Exchange among Three Sites as Obtained by Total Line Shape Analyses of 1H NMR Spectra: The Case of Methylene Signals
Authors: \={O}ki Michinori , Kono Motomichi , Kihara Hiroshi , Nakamura Nobuo
Published: July 2006

Benzyl methylene signals, which split into an AB quartet and a singlet and show temperature dependence, are obtained at various temperatures and are simulated with the use of two independent rates of rotation. Certain limitations of accuracy are found in this method. The uncertainty becomes less if additional data are provided from other sources, but never becomes negligible. Contribution of the slower process is found difficult to detect especially when the population involved in the process are the less.
Syntheses of Cecropia Juvenile Hormones by Selective Side-chain Methylation of (E,E)-Farnesol
Authors: Yasuda Arata , Tanaka Shin , Yamamoto Hisashi , Nozaki Hitosi
Published: July 2006

The stereoselective route to the title insect hormones (JH-1 & JH-2) depends crucially on the epoxidation of allylic alcohols with t-butyl hydroperoxide in the presence of oxobis(2,4-pentanedionato-O,O′)vanadium(IV). The oxidation of 2-methyl-1-hepten-3-ol exclusively produces the (2R*,3S*) isomerofthe diastereomeric epoxy alcohols. This is converted into (Z)-6-methyl-5-undecene by the sequence involving oxirane reaction with lithium dibutylcuprate(I) and the removal of both hydroxyl groups of the resulting 1,2-diol. Extension of the series of reactions to the mono- and bisoxirane derived from (E,E)-farnesol gives JH-2 and JH-1, respectively.
Synthesis of D:A-Friedo-18β-lupane Derivatives
Authors: Yokoyama Yasushi , Tsuyuki Takahiko , Moriyama Yoshihiko , Murae Tatsushi , Toyoshima Hirokazu , Takahashi Takeyoshi
Published: July 2006

D:A-Friedo-18β-lup-19-ene and D:A-friedo-18β-lup-19-en-3-one with a new migrated lupane framework were synthesized and the former compound was converted into known methyl trinorshionanoate.
The Ullmann Condensation Reaction of Haloanthraquinone Derivatives with Amines in Aprotic Solvents. IV. Kinetic Studies of the Condensation with Ethylenediamine
Authors: Arai Sadao , Tanaka Akira , Hida Mitsuhiko , Yamagishi Takamichi
Published: July 2006

In the Ullmann condensation of bromoanthraquinones (AQBr) with ethylenediamine using copper(I) bromide as a catalyst, the reaction rate decreased with time which has been interpreted in terms of the formation of the ineffective copper(II) species. The kinetic investigation showed the reaction rate to be first order both for the copper(I) species and AQBr. After prolonged reaction the copper(I) species was quantitatively converted to the copper(II) species, the copper(II) species appearing to have little catalytic activity due to strong coordination with ethylenediamine. The reactivities of the haloanthraquinones were dependent on the ease of coordination with Cu(I) and the rate of Cu(II) formation. The mechanism, including the reaction between CuI(AQBr) and ethylenediamine, has been proposed and discussed.
Photochemical and Thermal Reactions of Cyclohexadienone Oximes
Authors: Okazaki Renji , Watanabe Masako , Inamoto Naoki
Published: July 2006

Photolysis of (E)-1-hydroxyimino-2,4,5-tri-t-butyl-6-methyl-2,4-cyclohexadiene (1) and the corresponding (Z)-isomer in methanol, benzene, or pentane afford 1,3,5-tri-t-butyl-5-cyano-1,3-cyclohexadiene (3), 5-t-butyl-7-cyano-2,2,3,8,8-pentamethyl-3,4,6-nonatriene (4), 5-t-butyl-3-cyano-2,2,7,8,8-pentamethyl-3,4,6-nonatriene (5), 5-t-butyl-7-cyano-2,3,3,8,8-pentamethyl-1,4,6-nonatriene (6), 5-t-butyl-3-cyano-7-methoxy-2,2,7,8,8-pentamethyl-3,5-nonadiene (7), 5-t-butyl-7-cyano-7-methoxy-2,2,3,8,8-pentamethyl-3,5-nonadiene, and 2,4-di-t-butyl-6-cyano-7,7-dimethyl-1,3,5-octatriene (9). The presence of an oxaziridine in the reaction mixture has been confirmed by iodometry. The photoreaction in the presence of 1,3-pentadiene or oxygen gives essentially the same results, suggesting the involvement of the singlet excited state in these photoreactions. Thermal Beckmann rearrangement of 1 has been conducted for comparison to give only 6, 7, and 9. The photochemical formation of 3–9 has been rationalized in terms of the “free” cyclopentadienyl cation formed by ionic α-cleavage of the oxime. Photoreaction of 1-hydroxyimino-2,4,6-tri-t-butyl-2,4-cyclohexadiene with one alkyl group at 6-position gives 5-t-butyl-7-cyano-2,3,8,8-tetramethyl-1,4,6-nonatriene, 5-t-butyl-3-cyano-8-methoxy-2,2,7,8-tetramethyl-4,6-nonadiene, 5-t-butyl-7-cyano-2-methoxy-2,3,8,8-tetramethyl-3,5-nonadiene, and 1,3-di-t-butyl-5-cyano-3-methoxy-6,6-dimethyl-1,4-heptadiene.
A Stereoselective 1,3-Transposition Reaction of Allylic Alcohols
Authors: Yasuda Arata , Yamamoto Hisashi , Nozaki Hitosi
Published: July 2006

Reduction of glycidyl mesylate with dissolving metal produces allylic alcohol in fair to excellent yield. Combined with the highly stereoselective epoxidation of allylic alcohols with t-butyl hydroperoxide and oxobis(2,4-pentanedionato-O,O′)vanadium(IV) as a catalyst, the sequence provides a new and efficient means for 1,3-trans-position of allylic alcohols, by which geraniol is transformed into linalool, farnesol into nerolidol, and furthermore, (−)-cis-carveol into the (+) antipode and vice versa in a stereospecific way.
A Theoretical Approach to the Possible Hydrogen Migration in Butadiene under Electron Impact
Authors: Takagi Tsutomu , Oiwa Masayoshi
Published: July 2006

The hydrogen migration in butadiene under electron impact was studied by means of the calculated potential energy surfaces. The all-valence electron semi-empirical SCF-MO(MINDO/2-Unrestricted Hartree Fock) theory was employed. The possibility of the migration of hydrogen has been discussed. Moreover, the mechanisms (I–IV) including the hydrogen migration for the formation of the C3H3 ion have been discussed. The hydrogen-migration models are presented based on the variations in the total and the partitioned energies. It is very probable that the hydrogen on C1 in the M\underset.+ ion migrates to the other carbon, C4, via Models 1 and 2 in Mechanism IV. It was predicted that the formation of the C3H3 ion occurs by means of the fragmentation of the migrated M\underset.+ ion, although the other mechanisms can not always be ignored. Finally, for the hydrogen-migration models, the theoretical predictions were found to be in good agreement with the available experimental results.
A Study of the Reduction Mechanism of p-Dimethylaminobenzaldehyde to 1,2-Bis(p-dimethylaminophenyl)-1,2-ethanediol by Rotating Disk Electrode Voltammetry
Authors: Taniguchi Isao , Yasukouchi Kazuo , Yoshiyama Akiko , Sekine Taro
Published: July 2006

Rotating disk electrode voltammetry was applied to study the reduction mechanism of p-dimethylaminobenzaldehyde (1) in water–ethanol alkaline solutions by using a mercury-plated platinum rotating disk electrode. In the logarithmic analysis of the wave, the plots of log [i2⁄3/(id–i)] vs.  E showed good linearity, and the shifts of the half-wave potential with an increase in the rotation speed of the electrode (ω) and in the initial concentration of 1 (C) were ∂E1⁄2⁄∂logω=−22±2 mV and ∂E1⁄2⁄∂logC=19±2 mV, respectively. On the other hand, no appreciable change in E1⁄2 was observed with varying alkalinities of the solutions. These results and the large shift of E1⁄2 with an increase in the concentration of water (∂E1⁄2⁄∂log[H2O]=ca. 50 mV) are explained in terms of the following reactions:

R+e\ightleftarrowsR\ewdot (solvated by water), (1)

2R\ewdot\oversetk→D2− (r.d.s.), (2)

D2−+2H2O→DH2+2OH−, (3)

where R and R\ewdot are the molecule and the radical of 1, respectively, D2− is the dimer of R\ewdot and DH2 is the hydro-dimer (2) of R. The rate of the dimerization reaction (k in Eq. 2) was estimated to be 2.5×104 M−1 s−1 from the shift of E1⁄2 with logω for the 50% water-ethanol solution containing 1 M NaOH, and this rate constant decreased with decreasing water concentration.