bluuebunny/crossref_metadata_2025 huggingface dataset:
Magnetic Circular Dichroism Spectra of Cobalt(III) Complexes in the Second d–d Absorption Band Region
Authors: Matsuoka Nobuko
Published: July 2006

The MCD spectra of seventeen cobalt(III) complexes were measured in the visible and near-ultraviolet regions. Their behavior in the second d–d absorption band region were compared with those of the [Co(ox)x(gly)y(en)z] series comprising sixteen complexes (x, y, z=0, 1, 2, 3; and x+y+z=3), in which a positive band had been observed on the lower-energy side of the main negative band in this region. For the present work, the positive band was found in [Co(tn)3]3+, cis-[Co(ox)2(NH3)2]−, cis-[Co(OH2)2(en)2]+, trans-[Co(β-ala)2(en)]+, mer- and fac-[Co(picol)3] (picol=picolinate(1–)), and [Co(acac)3]. It is pointed out that all the complexes exhibiting a positive band were the tris(chelate) or cis-bis(chelate) types. Therefore the origin of this band is discussed in terms of the arrangement of two or three chelate rings. A positive band was not observed for complexes containing a CO32− ligand, even if they were a tris(chelate) or cis-bis(chelate) type. This is explained from a structural basis. The two complexes which had a split second d–d absorption band, mer-trans(NH3)-[CoCO3(gly)(NH3)2] and [CoCO3(picol)(NH3)2], showed two negative bands in the corresponding regions to both component absorption bands, in each complex.
Spectroscopic and MO Study of Peptide Models for the M412 Intermediate of Bacteriorhodopsin. Nε-Retinylidenelysyl Peptides Containing Aromatic Amino Acids
Authors: Sakurai Minoru , Tomomasa Satoshi , Seiya Yûji , Inoue Yoshio , Chûjô Riichirô
Published: July 2006

N ε-Retinylidenelysyl peptides containing Tyr and Phe were prepared in order to investigate the effect of the surrounding microenvironment on the absorption maximum of the chromophore of bacteriorhodopsin. The absorption maximum of the retinylidene Schiff base of the lysyl peptide, Boc–Lys–Phe(or –Gly)–Tyr–OMe, was shifted to the red relative to the peptides lacking Tyr, Boc–Lys–Phe–Phe–OMe and Boc–Lys–Phe–OMe. UV and 13C NMR studies on the Tyr-containing lysyl-peptide have confirmed an intramolecular interaction between Tyr and the retinylidene portion in low dielectric media. A hydrogen-bond formation of the Schiff base with a Tyr side chain is supported by a theoretical estimation of the transition energy and the shielding constants for some models of Tyr-Schiff base complexes. The side-chain conformation of the Tyr-contaning lysyl-peptide is discussed in terms of the 1H NMR data. The hydrogen-bonding shift induced by Tyr was estimated as being no less than 10 nm.
Synthesis of Amides and Amidines by Reaction of Carboxylic Acids and Amines in the Presence of Polyphophoric Acid Trimethylsilyl Ester (PPSE)
Authors: Ogata Shin-ichi , Mochizuki Amane , Kakimoto Masa-aki , Imai Yoshio
Published: July 2006

The reaction between amines and carboxylic aicds in the presence of polyphosphoric acid trimethylsilyl ester (PPSE) has been investigated from the view point of the synthesis of amides and amidines. Benzanilide was selectively prepared from benzoic acid and aniline in the presence of PPSE and pyridine at 100 °C, whereas a mixture of benzanilide and N,N′-diphenylbenzamidine was obtained without the use of pyridine. The reaction at 160 °C almost exclusively gave N,N′-diphenylbenzamidine. Various symmetrical amidines were obtained from combinations of carboxylic acids and aromatic amines in high yields by simply heating at 160 °C with four molar amounts of PPSE. The reactions of aliphatic and aromatic amines with N-monosubstituted and N,N-disubstituted amides also afforded corresponding unsymmetrical amidines under the same conditions. The reaction mechanism is discussed in some detail.
Photochemical Reaction of 2-Aryl-1,2-benzisoselenazol-3(2H)-ones
Authors: Kamigata Nobumasa , Iizuka Hirokazu , Izuoka Akira , Kobayashi Michio
Published: July 2006

The photochemical reaction of 2-aryl-1,2-benzisoselenazol-3(2H)-ones (1) in benzene was found to give dibenzo[b,f][1,4]selenazepin-11(10H)-ones (2). On the other hand, the photochemical reaction of 1 in t-butyl alcohol afforded 2-(2-hydroxy-2-methylpropylseleno)benzanilide, 2-(methylseleno)benzanilide, and 2-aryl-1,2-benzisoselenazol-3(2H)-one 1-oxides together with the photoisomer 2. Mechanisms for these reactions are proposed.
Synthesis and Conformation of Aromatic Cyclic Dipeptides. Cyclo(phenylalanyl)2, Cyclo(1-naphthylalanyl)2, and Cyclo(2-naphthylalanyl)2
Authors: Egusa Syun , Takagi Jun , Sisido Masahiko , Imanishi Yukio
Published: July 2006

Cyclic dipeptides of aromatic amino acids, cyclo(l-phenylalanyl)2, cyclo(l-1-naphthylalanyl)2, and cyclo(l-2-naphthylalanyl)2 were synthesized and subjected to spectroscopic analyses using 1H NMR, absorption, circular dichroism (CD), fluorescence, and fluorescence-detected circular dichroism (FDCD). The 1H NMR data suggested that the 2,5-piperazinedione rings of the three cyclic dipeptides are in planar or nearly planar bowsplit boat-type conformation. The aromatic side groups of cyclo(1- and 2-naphthylalanyl)2’s were found to take asymmetric configurations, one naphthyl group being folded onto the 2,5-piperazinedione ring, the other being unfolded. Strong exciton couplet was observed in CD spectra of the three compounds. The signs of the exciton splitting were opposite in the two naphthyl cyclic dipeptides. Fluorescence spectra of the two naphthyl cyclic dipeptides showed no excimer emission. The absence of strong interchromophoric interaction in the lowest excited state was also suggested by the virtual coincidence of CD spectrum with FDCD spectrum. From the above spectroscopic data, probable conformations were proposed for the naphthyl cyclic dipeptides.
Stereochemistry of Hydroxymethylations of N-Salicylideneglycyl Dipeptide Copper(II) Complexes. A Kinetically and Also Thermodynamically Controlled Reaction
Authors: Harada Kaoru , Suzuki Shinnichiro , Narita Hideyuki , Watanabe Hiroshi
Published: July 2006

(N-Salicylideneglycyl-l-valinato)copper(II) or (N-salicylideneglycyl-l-isoleucinato)copper(II) was treated with formaldehyde in an aqueous solution under relatively mild conditions. It was found that the resulting seryl residue was d-configuration in the early stage of the reaction. However, the configuration was inverted from d- to l-form after prolonged reaction. The epimerization reactions of authentic (N-salicylideneglycyl-d- or l-seryl-l-isoleucinato)copper(II) were carried out under similar conditions. These results indicate that the reaction as a whole is controlled kinetically as well as thermodynamically.
Recovery of Highly-Purified Rare Earth Elements Using Newly-Synthesized Chelating Resins
Authors: Takeda Kunihiko , Akiyama Minoru , Kawakami Fumiaki , Sasaki Mitsunaga
Published: July 2006

The chromatographic separation of rare earth elements was studied using newly-synthesized chelating resins which have EDTA (ethylenediaminetetraacetic acid) and DTTA (diethylenetriaminetetraacetic acid) pendant groups. The chromatography using EDTA- and DTTA-chelating resins gave excellent separation results, while the IDA-chelating resin was not satisfactory. The DTTA-type resin was especially effective, allowing highly purified rare earth elements to be recovered. The separation efficiency of each resin was attributed mainly to the difference in its complexing capability among rare earth ions. Prior to experimentation, the chromatographic conditions were assessed and optimized by computer simulation based on newly introduced equations. The simulation results were effective in the case of Pr3+/Nd3+ for determining the experimental conditions. An analysis of the experimental results helped to elucidate the mechanism of the chromatographic separation while using the simulation results.
Conformation of Condensed Polycyclic Aromatic Hydrocarbons. II. The Molecular and Crystal Structure of Violanthrene B (Dibenzo[a, rst]naphtho[8,1,2-cde]pentaphene)
Authors: Oonishi Isao , Fujisawa Shoji , Aoki Junji , Ohashi Yuji , Sasada Yoshio
Published: July 2006

The title compound, C34H18, has been obtained by reducing violanthrone B, a byproduct in the synthesis of violanthrone. Its structure has been determined by on X-ray analysis. The space group is P21/c, with unit-cell dimensions a=25.78(1), b=3.807(5), c=19.975(8) Å, β=96.55(3)°, and Z=4. The structure was solved by the direct method and refined by a block-diagonal least-squares method to an R value of 0.076 on the basis of 1242 independent reflections. The molecules are largely distorted from a planar structure owing to a steric repulsion between the intramolecular overcrowded hydrogen atoms. Also, they are stacked face-to-face to form a column structure along the b-axis.
Infrared Multiple-Photon Decomposition of β-Propiolactone
Authors: Yamamoto Shunzo , Ishikawa Yo-ichi , Arai Shigeyoshi
Published: July 2006

The infrared multiple-photon decomposition of β-propiolactone was found to give only ethylene and carbon dioxide with the same yield as the products, where the material balance was above 90%. This result suggests that the unimolecular decomposition into ethylene and carbon dioxide is a unique reaction channel of the compound at highly vibrationally excited states. It was shown that the decomposition probability was strongly dependent on the fluence but slightly dependent on the pressure.
Ion/Molecule Reactions in Gaseous Acetone
Authors: Hiraoka Kenzo , Takimoto Hajime , Morise Kazuya , Shoda Takashi , Nakamura Shizuo
Published: July 2006

The ion/molecule reactions in acetone were investigated which were induced by the electron impact. It was found that the protonated acetone reacts with an acetone molecule to produce the protonated diacetone alcohol (4-hydroxy-4-methyl-2-pentanone) and the protonated mesityl oxide (4-methyl-3-penten-2-one) through the aldol condensation reaction. It was also found that the acetone molecule isomerizes from keto to enol form in the interaction with the chloride ion. The thermochemical data for the higher-order clustering reactions of the proton and chloride ion with acetone molecules were obtained.
An Important Metal Complex in the Asymmetric Synthesis of α-Amino Acids. The Crystal and Molecular Structure of (−)546-((R)-Alaninato)((6R,8R)-6,8-dimethyl-2,5,9,12-tetraazatridecane)cobalt(III) Bromide Trihydrate, (−)546-[Co(R-ala)(1,5R,7R,11-Me4-2,3,2-tet)]Br2·3H2O
Authors: Yashiro Morio , Ajioka Masanobu , Yano Shigenobu , Toriumi Koshiro , Ito Tasuku , Yoshikawa Sadao
Published: July 2006

The crystal and molecular structures of (−)546-((R)-alaninato)((6R,8R)-6,8-dimethyl-2,5,9,12-tetraazatridecane)cobalt(III) bromide trihydrate ((−)546-[Co(R-ala)(1,5R,7R,11-Me4-2,3,2-tet)]Br2·3H2O) (1), derived from (−)546-[Co(AMM)(1,5R,7R,11-Me4-2,3,2-tet)]+ on decarboxylation, have been determined from three-dimensional X-ray counter data. In the above, AMM is an α-amino-α-methylmalonate ion. The compound crystallizes in an orthorhombic space group P212121 with a=11.713 (1) Å, b=20.301 (2) Å, c=10.113 (2) Å, and Z=4. The structure was solved by the heavy-atom method followed by full-matrix least-squares and Fourier techniques. A refinement using 2168 reflections with |Fo|>3[σ(Fo)] gave R=0.052. The absolute configuration of the complex cation is Λ in the β2 form. The gauche conformations of two five-membered chelate rings for the tetramine are both δ, and the central six-membered chelate ring adopts a chair conformation with one methyl group axial and the other equatorial. All the secondary nitrogen atoms have S configurations except one of the terminal nitrogen atoms whose absolute configuration is R. The N-methyl group in an “out-of-plane” five-membered chelate ring is equatorial; however, the other in an “in-plane” five-membered chelate ring has an axial disposition. The alaninate ion coordinates to the cobalt via N and O atoms. The absolute configuration around the carbon center of the alanine was found to be R.
Measurements of Association Constants of Iodine with Cyclodextrins and with Iodide or Bromide Ion in Aqueous Medium, Based on Volatilization Rate of Iodine from Aqueous into Gaseous Phase
Authors: Sanemasa Isao , Nishimoto Yuko , Tanaka Akira , Deguchi Toshio
Published: July 2006

Iodine molecules, which are volatile, are expelled from an aqueous medium into the gaseous phase by introducing an inert gas at a constant flow rate into the aqueous phase, and the amount of the released iodine is measured as a function of aeration time. In the presence of a nonvolatile solute which associates with molecular iodine, the releasing rate of the volatile solute is reduced with increasing degree of the association between both the solutes in the aqueous medium. The method was applied to the case of association of iodine with α-, β-, or γ-cyclodextrin; the formation constants of the three 1:1 complexes are (1.5±0.1)×104, (1.5±0.2)×102, and 24±3 dm3 mol−1, respectively, at 25.0 °C and low ionic strengths. The complexation of iodine with iodide or bromide ion was also studied; the I3− and I2Br− formation constants are (6.5±0.1)×102 and 16±1 dm3 mol−1, respectively, at 25.0 °C and I=0.1(NaClO4).
The Effect of Tetraalkylammonium Ions on the Distribution of the Silicate Anions in Aqueous Solutions
Authors: Hasegawa Isao , Kuroda Kazuyuki , Kato Chuzo
Published: July 2006

The effect of the addition of tetramethylammonium, (2-hydroxyethyl)trimethylammonium and benzyltrimethylammonium ions on the distribution of the silicate anions arising from the hydrolysis of tetraethoxysilane was studied by using the trimethylsilylation method. The selective formation of the octameric silicate anion with a double four-membered cage was confirmed in these solutions. It was found that tetraalkylammonium ions with three methyl groups, whether or not the other group was a methyl group, contributed to the formation of a double four-membered cage octamer.
Kinetics of Ligand-Exchange Reactions in Tetrakis(acetylacetonato)uranium(IV) in Organic Solvents
Authors: Fukutomi Hiroshi , Ohno Hideki , Tomiyasu Hiroshi
Published: July 2006

The kinetics of ligand-exchange reactions between tetrakis(acetylacetonato)uranium(IV) [U(acac)4] (acac=acetylacetonate) and free acetylacetone Hacac in various organic solvents, CDCl3, C6D6, and CD3CN has been studied by 1H NMR. The rate laws were found to change remarkably with these solvents used. The observed first-order rate constant kobsd in CDCl3 depended linearly on the concentration of free Hacac in the enol form as kobsd=ks[Hacac]enol, while the plots of kobsd vs. [Hacac]enol in C6D6 deviated from straight lines in higher concentrations of Hacacenol. The exchange rate was much slower in CD3CN than in CDCl3 and C6D6, and kobsd increased only slightly with [Hacac]enol. Addition of dimethyl sulfoxide (DMSO) in C6D6 yielded the retardation of exchange rate giving a rate law kobsd−1=p+q[DMSO], where p and q are constants. From the results obtained in these solvents, a mechanism passing through nine-coordinate intermediates was proposed.
Preparation and Thermal Square Planar–Octahedral Transformation of Nickel(II) Complexes Containing 1,2-Butanediamine or 3,3-Dimethyl-1,2-butanediamine in Solid Phase
Authors: Ihara Yoshinori , Wada Akiko , Fukuda Yutaka , Sone Kozo
Published: July 2006

Nickel(II) complexes of 1,2-butanediamine(1,2-bn) and 3,3-dimethyl-1,2-butanediamine(dmbn), were prepared, and their thermal behavior was investigated in solid phase. The original complexes were all violet, octahedral diaquabis(diamine) complexes([Ni(H2O)2(1,2-bn/dmbn)2]X2; X=Cl, Br, NO3, or ClO4). The 1,2-bn complexes with Cl− or Br− and the dmbn complex with NO3− showed a two-step thermochromism, violet→yellow→violet blue, upon heating. These steps correspond to structural changes to a square planar anhydride, and then to an octahedral dianiono complex. The complexes of both ligands with ClO4− underwent only thermal deaquation, changing into orange square planar anhydride. Other salts, the 1,2-bn complex with NO3− and the dmbn complexes with Cl− or Br−, were converted into octahedral dianiono complexes by thermal deaquation-anation which occurs in one step. The differences among the thermal reactivities of the complexes with different diamines can be understood on the basis of steric hindrance caused by the substituent groups on the diamine.
Synthesis of the 3H-Azepines Utilizing the Thermolysis of Substituted Aryl Azides
Authors: Ohba Yoshihiro , Kubo Shinji , Nakai Masaaki , Nagai Atsunori , Yoshimoto Masayo
Published: July 2006

Thermolysis of several p-substituted aryl azides (p-R-C6H4N3; R=COCH3, CO2CH3, COPh) in methanol gave 5-substituted 2-methoxy-3H-azepines in moderate yields. Thermolysis of m-substituted aryl azides (m-R-C6H4N3; R=COCH3, CO2CH3, COPh, NO2) gave 4-substituted 2-methoxy-3H-azepines and 6-substituted 2-methoxy-3H-azepines in good yields. In contrast, thermolysis of p-azidoacetophenone in piperidine gave 5-acetyl-2-piperidino-3H-azepine and an unusual product, 6-acetyl-2-piperidino-3H-azepine, and p-aminoacetophenone.
The Synthesis of Dihydro-2(3H)-thiophenone Derivatives
Authors: Taguchi Yoichi , Suhara Yasuo
Published: July 2006

The reaction of 2,2-dimethylthiirane (4) with diethyl malonate (5) in the presence of sodium ethoxide gave 3-ethoxycarbonyl-5,5-dimethyl-dihydro-2(3H)-thiophenone (6) and a polymer. The yield of 6 could be increased to 65%. The reaction of thiirane, 2-methylthiirane, 2-butylthiirane, 2-hexylthiirane, 1,2-epithiocyclohexane, and 2-phenylthiirane with 5 also gave corresponding dihydro-2(3H)-thiophenone derivatives. Although the reaction of an alkyl-substituted thiirane with 5 selectively gave a product formed by an attack of a carbanion at the less-hindered carbon of the thiirane ring, the major product of the reaction of 2-phenylthiirane with 5 was an isomer formed by an attack at the more hindered carbon of the thiirane ring. The reaction of 4 with ethyl acetoacetate gave 3-acetyl-5,5-dimethyl-dihydro-2(3H)-thiophenone selectively. A product 6 was also obtained by a reaction of 4 with 5 by using sodium hydride instead of sodium ethoxide.
A Study of the Color of Coal Liquids. II. Involvement of Light, Oxygen, Phenols, and Aromatic Amines in Formation of Colored Materials from Wandoan-Coal-Derived Liquids
Authors: Futamura Shigeru , Kamiya Yoshio
Published: July 2006

Triggering materials responsible for coloring of coal liquids have been searched by comparing the structures of the colored materials derived from the neutrals, acids, and bases of the coal liquid and the nitrogenous model compounds. Basic constituents of the coal liquid are most prone to photooxidation and afford colored materials of higher molecular weight and stronger absorption in the visible region. Model compound studies suggest that they are predominantly formed in the photoinduced oxidative coupling of aromatic amines.
Temperature Effect on the Rhodium-Catalyzed Direct Synthesis of Ethylene Glycol from Carbon Monoxide and Hydrogen in Several Solvents
Authors: Masuda Takashi , Murata Kazuhisa , Kobayashi Toshiaki , Matsuda Akio
Published: July 2006

The Rh4(CO)12/N-methyl-2-pyrrolidone system is featured in that the rate of ethylene glycol (EG) formation is significantly accelerated with increasing reaction temperature. The turnover frequency of EG at 300 °C and 2000 kg/cm2 (H2/CO=1) is about 2000 h−1. The Rh4(CO)12/tributylamine system also has a high catalytic activity at a high temperature.
The Direct Preparation of Flavones from 2′-Hydroxychalcones Using Disulfides
Authors: Hoshino Yukio , Oohinata Toshinori , Takeno Noboru
Published: July 2006

Flavone was obtained by a reaction of 2′-hydroxychalcone with disulfides in good yield. Among several disulfides, diphenyl disulfide gave the best result. Under the same conditions, some flavones were obtained from the corresponding 2′-hydroxychalcones in satisfactory yields.
New Piperidinic Synthons via Ring Contraction. Formal Synthesis of (±)-Perhydrohistrionicotoxin
Authors: Duhamel Pierre , Kotera Mitsuharu , Monteil Thierry
Published: July 2006

The 2,2-bifunctionalized piperidines 6 and 10 were obtained via ring contraction of the seven-membered heterocyclic enamino aldehyde 5 in nearly quantitative yield. The synthesis of 1-benzyl-1-azaspiro[5.5]undec-7-en-9-one 9 (a formal precursor of perhydrohistrionicotoxin 1b) in 3 steps from the piperidinedialdehyde monoacetal 6, is reported.
Electron-Transfer Reactions between Cobalt(III) Complexes and Polymer-Bound Ferrous Chelate
Authors: Kurimura Yoshimi , Takato Kiyomi , Suzuki Norihisa
Published: July 2006

The reductions of some cobalt(III) complexes having overall charges of −1 to +3 by the polymer-bound ferrous chelate, Fe(II)–PBDA (PBDA=vinylbenzylamine-N,N-diacetate-co-4-styrenesulfonate), and the effect of sodium chloride on the reduction rate have been investigated. The specific rate increases sharply with the positive charge on the Co(III) complexes by electrostatic interactions between reactant species.
Photochemical Reaction of Tricarbonyl(η-methylcyclopentadienyl)manganese(I), [Mn(CO)3(MeCp)], with 1,1′-Bis(diphenylphosphino)ferrocene, (dppfe), and X-Ray Molecular Structure Analysis of [Mn(CO)(MeCp)(dppfe)]
Authors: Onaka Satoru
Published: July 2006

Photochemical reaction of MeCpMn(CO)3 with (Ph2PC5H4)2Fe, (dppfe), was conducted in benzene. From the reaction mixture, the title compound [Mn(CO)(MeCp)(dppfe)] was isolated and its molecular structure was solved by X-ray analysis. ν(CO) peak at 1810 cm−1 of the title compound was clarified to be originated from the terminal carbonyl. Temperature-dependent 1H NMR spectra were also measured for the title compound.
NMR Spectra of Dimethyl 1-Acetyl-1,2-dihydro-2-quinolyl-phosphonate and Related Compounds
Authors: Suezawa Hiroko , Hirota Minoru , Shibata Yasuhiro , Takeuchi Isao , Hamada Yoshiki
Published: July 2006

1H, 13C, and 31P NMR spectra of the products from the Reissert type reactions using acyl halides and trimethyl phosphite were measured and correlated with their structures. 31P Chemical shift of dimethoxyphosphinyl group and 13C chemical shift of the α-carbon atom, as well as 1JCP and 2JPH, can be criteria to differentiate the 1,2- and the 1,4-adducts from each other. Thus, there NMR parameters can be a clue to elucidate the regioselectivity of the reactions.
Metal Carbonyl-Induced N–O Bond Cleavage of the Oxime Group
Authors: Nitta Makoto , Iino Yukio
Published: July 2006

The reaction of [Mo(CO)6] or [Fe2(CO)9] with oxime O-acetate of 1,3-diphenyl-2-propen-1-one undergoes a reductive N–O bond cleavage to give an imine which dimerises and/or is hydrolyzed to ketones. The dimer, so formed, undergoes fragmentations to give pyridine and pyrimidine derivatives. Similarly, the reaction of [Mo(CO)6] with several oxime O-acetates, oximes, and an oxime ether were shown to give the corresponding ketones. A reaction of oxime O-acetates with [Cr(CO)6] or with [W(CO)6] to give the corresponding ketones was also shown to proceed very slowly.
A New Phase-Transfer Porphyrin Catalyst for the Olefin Epoxidation
Authors: Takagi Shigeru , Miyamoto T Ken , Sasaki Yukiyoshi
Published: July 2006

A new type of amphiphilic porphyrin has been synthesized and its manganese(III) complex has been used as a catalyst for the epoxidation of olefin. Catalytic oxygenation in a two-phase (CH2Cl2/H2O) system has been undertaken in the absence of a phase-transfer reagent, such as benzyldimethyltetradecylammonium chloride.
Solvent Effects on the nπ* and ππ* Absorption Intensities of Some Organic Molecules
Authors: Abe Takehiro , Iweibo Idowu
Published: July 2006

Recently proposed experimental and theoretical expressions for the molecular electronic oscillator strength in a solution (J. Chem. Phys., 83, 1546 (1985)) have been succesfully applied to the spectral data of some nonpolar and polar organic molecules (benzoquinones, ketones, nitroalkanes, β-carotene, and substituted benzenes). In an application of the theoretical expression, the transition moment of a nonpolar solute molecule in various solvents was assumed to be approximately constant, while that of a polar solute molecule was developed on the assumptions of a first-order perturbation of the wave function and a Block–Walker reaction field. The ratio of the oscillator strength in a solution to that either in a vapor or a specified solvent was computed from both experimental data and theoretically from the transition moments. The results of the two computational modes are, generally, in good agreement for the range of compounds studied.
Photochemical Reactions of Pentakis(N,N-dimethylformamide)dioxouranium(VI) Ions in Nonaqueous Solutions
Authors: Fukutomi Hiroshi , Harazono Toshie , Kojima Takashi
Published: July 2006

Photochemical reactions of [UO2(dmf)5]2+ (dmf=N,N-dimethylformamide) ions were investigated in DMF and acetone solutions. The photolysis product of [UO2(dmf)5]2+ at the initial stage was U(V), which was so stable in acid-free organic solvents in the dark that the absorption spectrum of U(V) was easily obtained in DMF. The molar extinction coefficient of U(V) was determined to be 45.5±1.5 M−1 cm−1 (M=mol dm−3) at 755 nm. The formation of U(V) seems to proceed through the intramolecular reaction (ki) and the lower limit of ki was determined to be about 107 s−1 from the lifetime of excited uranyl ions by using a laser flash photolysis.
The Crystal and Molecular Structure of 12-Bromo[2.2][2.2]triple-Layered Paracyclophane
Authors: Koizumi Yosuke , Toyoda Toshihiro , Miki Kunio , Kasai Nobutami , Misumi Soichi
Published: July 2006

The molecular structure of 12-bromo[2.2][2.2]paracyclophane has been determined by means of X-ray diffraction. The crystal is orthorhombic, space group Pbcn, a=12.768(1), b=11.515(1), c=13.074(1) Å, Z=4. The structure was solved by the heavy-atom method, and refined anisotropically by the block-diagonal leastsquares procedure; R=0.062. The Br–C···C–H axis of the central benzene ring lies on a crystallographic two-fold axis. The outer benzene rings take a boat form, and the central benzene ring is twisted.
Raman Spectral Characteristics of [Co(ida)n(dien)2−n]-Type and Related Complexes
Authors: Kawamoto Tatsuya , Maruyama Toshihide F , Yasui Takaji , Okamoto Ken-ichi , Hidaka Jinsai , Einaga Hisahiko
Published: July 2006

The Raman spectra of [Co(ida)n(dien)2−n](3−2n)+(n=0, 1, and 2), where ida and dien denote iminodiacetate and diethylenetriamine respectively, and related complexes in the skeletal vibration region were measured in order to deduce the relation between their spectra and their geometrical structures. The Raman bands could be classified into five vibration modes: Totally symmetric stretching vibration modes (polarized bands in the 510–625 cm−1 region); Co–O and Co–N stretching vibration modes (depolarized bands in the 430–525 cm−1 region); metal-ligand skeletal breathing vibration modes (polarized bands in the 360–480 cm−1 region); skeletal bending deformation modes (depolarized bands in the 290–405 cm−1 region), and chelate ring deformation modes (polarized bands in the 220–260 cm−1 region). The polarized bands around 400 cm−1 were regarded as characteristic of the mono and bis(terdentate)cobalt(III) complexes. The mer isomers of each complex gave Raman spectra clearly different from those of the fac isomers in the stretching vibration region.
Crystal Structure and Molecular Motion of Tetramethylammonium Hexaiodotellurate(IV–Iodine (1/1) Compound
Authors: Kiriyama Hideko , Nishizaki Kyoko
Published: July 2006

The crystal structure of the title compound was determined by means of X-ray diffraction. The crystal data and the final R value are: [(CH3)4N]2TeI6·I2, tetragonal I41/acd, a=20.356(3) and c=27.571(5) Å, V=11,424(3) Å3, Z=16, R=0.082 for 1562 observed unique reflections. The structure consists of discrete [TeI6]2− anions and Me4N+ cations in an arrangement analogous to the K2PtCl6 structure and of additional I2 molecules bridging adjacent complex anions. The TeI6 octahedron is considerably distorted with Te-I distances of 2.933 (2), 3.017 (2), and 2.857 (2) Å, owing to different interaction with the surrounding I2 molecules. Two of three independent Me4N+ cations are orientationally disordered and distributed over each two positions. A phase transition was found at 234 K from DTA and its molar enthalpy was estimated to be approximately 2.4 kJ mol−1 from DSC. Proton NMR studies offered direct evidences for threefold reorientation of CH3 groups and overall rotation of Me4N+ cations taking place consecutively far below room temperatures. At 234 K the spin-lattice relaxation time T1 changes discontinuously by about one order of magnitude, suggesting the first order of transition. The activation energies of such composite reorientation in the fast regions (ωτc<<1) are 5.4 and 14.2 kJ mol−1 in the high- and low-temperature phases, respectively.
N-Hydroxy Amides. IV. Synthesis and Properties of a Trihydroxamic Acid Anilide as a Model for Ferrioxamines
Authors: Shimizu Kazuyuki , Nakayama Kazuyuki , Akiyama Masayasu
Published: July 2006

A trihydroxamic acid having a 6-aminohexanoyl–3-(hydroxyamino)propanoyl sequence has been synthesized in a stepwise manner, starting with glycinanilide. The trihydroxamic acid anilide bears a good structural resemblance with N-benzoyl-deferriferrioxamine B (Benzoyl-DFB). A plot of the absorbance vs. the molar ratio of iron(III) to the hydroxamate group indicates the formation of a 1:1 intramolecular iron(III) complex for the trihydroxamic acid anilide and Benzoyl-DFB. Cyclic voltammetry also shows that the iron complexes of both compounds have similar electrochemical properties. A solid iron(III) complex was obtained when the trihydroxamic acid anilide was mixed with tris(2,4-pentanedionato)iron(III) in methanol.
Effect of Pressure on the Pre-Steady-State Kinetics of the Hydrolysis of p-Nitrophenyl Pivalate Catalyzed by α-Chymotrypsin
Authors: Makimoto Syoichi , Suzuki Keizo , Taniguchi Yoshihiro
Published: July 2006

The pre-steady-state of the hydrolysis of p-nitrophenyl pivalate (pNPT) catalyzed by α-chymotrypsin (α-CHT) in Tris buffer solutions was measured up to 2.4 k bar at 25 °C. The reaction was initiated by substrate binding, and followed by acylation and deacylation processes. From the pressure dependence on the dissociation constants (Ks), the volume change ΔVKs was −14±1 cm3 mol−1. From the pressure dependence on the rate constants (kacyl and kdeacyl) of the acylation and deacylation processes, the activation volumes ΔVacyl\eweq and ΔVdeacyl\eweq were −24±1 and −2±1 cm3 mol−1, respectively. The reaction mechanisms of α-CHT are discussed in terms of the reaction and activation volumes.
Regioselective Carboxylation of Silicon-Stabilized Allylic Carbanions and the Synthetic Utility of 2-Silyl-3-butenoates
Authors: Uno Hidemitsu
Published: July 2006

Carbanions of allylic dimethylphenylsilanes show remarkable regioselectivity toward both carboxylation with carbon dioxide and methylation with methyl iodide. Methylation of these compounds occurred preferentialy at α position, although allyltrimethylsilane and allyltriphenylsilane are known to give γ selectivity toward the same electrophiles. Moreover, their aluminum “ate” complexes react with carbon dioxide regioselectively at the a position irrespective of methyl substitution pattern of the allylic moieties. The α-carboxylated allylic silanes proved to be useful synthons of 3-(methoxycarbonyl)allyl anions after esterification.
Methylation of Alcohols, Phenols, and Carboxylic Acids, and Selective Monomethylation of Diols and Dicarboxylic Acids with Dimethyl Sulfate by Use of Alumina
Authors: Ogawa Haruo , Ichimura Youko , Chihara Teiji , Teratani Shousuke , Taya Kazuo
Published: July 2006

Alcohols in cyclohexane give their methyl ethers in high yields by the use of a combination of dimethyl sulfate and alumina. Some diols and dicarboxylic acids adsorbed on alumina react with dimethyl sulfate and produce the corresponding monomethyl ethers and esters in high selectivities.
The Regulation of Emulsion Polymerization with Fluorocarbon–Hydrocarbon Emulsifiers Mixture
Authors: Kato Kazufumi , Esumi Kunio , Meguro Kenjiro
Published: July 2006

The emulsion polymerization of styrene using a mixture of sodium dodecyl sulfate (SDS) and lithium fluorooctane sulfonate (LiFOS) has been studied. The polymerization rate decreased upon increasing the mole fraction of LiFOS, and was dependent on the solubilized amount of styrene in mixed surfactant solutions of SDS and LiFOS. The particle size increased upon increasing the mole fraction of LiFOS on the whole, and the molecular weight of the polymer formed in latices decreased upon increasing the mole fraction of LiFOS. Furthermore, the molecular-weight distribution of the latex polymer formed in mixed emulsifier solutions was considerably wider than that of the latex polymer formed in a single-emulsifier solution. It was confirmed from the above results that LiFOS had a repressive effect on the polymerization rate, and that it affected the number of particles and the molecular weight in the emulsion-polymerization process.
Stability Constants and Some Other Properties of the Lanthanoid Nitrate Complexes with Tri-, Tetra-, and Pentaethylene Glycols
Authors: Hirashima Yoshiyuki , Kanetsuki Koji , Yonezu Ikuo , Isobe Noriyuki , Shiokawa Jiro
Published: July 2006

The lanthanoid nitrate complexes of tri-, tetra-, and pentaethylene glycols (EO3, EO4, and EO5) exhibited anomalous stability trends attributed to structures similar to those of crown complexes. The stability constants of the EO4 and the EO5 complexes decreased with an increase in the atomic number of the lanthanoid in contrast to the lanthanoid complexes with most other ligands. A maximum stability was found at europium for EO3 complexes. The decomposition temperatures of EO3 complexes were higher than those of the corresponding EO4 and EO5 complexes. The yields of the solid complexes in reactions of the lanthanoids with EO5 decreased with an increase in the atomic number of the lanthanoid (with some exceptions). The separation factors observed for fractional precipitation using EO5 as the separating reagents were comparable to those reported regarding reagents practically used for lanthanoid separation.
Rearrangement Approaches to Cyclic Skeletons. IV. The Total Synthesis of (±)-Pinguisone and (±)-Deoxopinguisone Based on Photochemical [1,3] Acyl Migration of a Bicyclo[3.2.2]non-6-en-2-one
Authors: Uyehara Tadao , Kabasawa Yasuhiro , Kato Tadahiro
Published: July 2006

The total synthesis of (±)-Pinguisone (2) and (±)-deoxopinguisone (3), [5–6] fused-ring sesquiterpenes, has been achieved starting from 1-methoxy-3,4,5-trimethylbenzene. 1-Methoxy-4,5,endo-8-trimethylbicyclo[2.2.2]non-5-en-2-one (9) was prepared selectively via facial selective Diels–Alder reaction of the diene derived from the benzene and 2-chloroacrylonitrile. Ring enlargement of 9 using (CH3)3SiCHN2 and BF3 etherate gave the corresponding bicyclo[3.2.2]oct-6-en-2-one (8). The photochemical [1,3] acyl migration of 8 gave the [5–6] fused-ring compound (7). The fourth methyl was introduced selectively by the conjugate addition of (CH3)2CuLi to the spiro[bicyclo[4.3.0]non-8-ene-3,2′-[1,3]dioxolan]-7-one prepared from 7. Each furan ring of 2 and 3 was constructed via the corresponding butenolide derived from the γ-keto acid by acid-catalyzed dehydration.
Reactions of 2,4,6-Tri-t-butylphenyllithium with O-Alkyl Selenoformates: Intermediate Formation of 2,4,6-Tri-t-butylselenobenzaldehyde
Authors: Ishii Akihiko , Okazaki Renji , Inamoto Naoki
Published: July 2006

2,4,6-Tri-t-butylphenyllithium reacts with O-alkyl selenoformates (1) at three different sites (i. e., the selenoformyl carbon, the selenoformyl hydrogen, and the selenium) to give 1,3,5-tri-t-butylbenzene, 2,4,6-tri-t-butylbenzaldehyde, 6,8-di-t-butyl-3,4-dihydro-4,4-dimethyl-1H-2-benzoselenin(11), bis(2,4,6-tri-t-butylphenylmethyl) di(and tri) selenides, bis(2,4,6-tri-t-butylphenyl) diselenide, and dibutyl diselenide depending on the reaction conditions and the alkyl group in 1. The formation of 11 is explained in terms of the intermediacy of 2,4,6-tri-t-butylselenobenzaldehyde, which is trapped by condensation reaction with butylamine leading to N-(2,4,6-tri-t-butylbenzylidene)butylamine. Mechanism for the formation of these products is also discussed.
Mercury- and Cadmium-Photosensitized Reactions of β-Propiolactone
Authors: Yamamoto Shunzo , Gohda Rinko , Morikawa Rie , Takahoso Hiroshi , Sueishi Yoshimi , Nishimura Norio
Published: July 2006

The mercury- and cadmium-photosensitized reactions of β-propiolactone (PL) have been investigated. The gaseous products from the mercury-photosensitized reaction were carbon dioxide, ethylene, carbon monoxide, ethylene oxide, acetaldehyde, and methane, while the products obtained in the cadmium-photosensitized reaction were carbon monoxide, ethylene oxide, and acetaldehyde. In the mercury-photosensitized reaction, the quantum yields of the products were independent of the lactone pressure at pressures higher than 1500 Pa, while in the cadmium-photosensitized reaction, the quantum yields of the products decreased with the increase in the lactone pressure. Several possible reaction schemes have been proposed to explain the above kinetic behavior. The mercury- and cadmium-photosensitized reactions proceed through different intermediates, that is, a triplet lactone in the former and an excited complex between an excited cadmium atom and a lactone molecule in the latter.
Selective Formation of 2-Phenylethanol in the Homologation of Benzyl Alcohol
Authors: Watanabe Kazuhiro , Kudo Kiyoshi , Mori Sadayuki , Sugita Nobuyuki
Published: July 2006

High selectivity of 2-phenylethanol (87%) in the homologation of benzyl alcohol was obtained with cobalt–ruthenium mixed catalyst. The formation of toluene as the major by-product was suppressed by adding water at low reaction temperature. Bromide as promoter was more effective for the homologation than chloride or iodide. From in situ IR observation, [Co(CO)4]−, which was active species for the homologation, was found to be produced by the dissociation of [CoH(CO)4] but not by the disproportionation of [Co2(CO)8] under the reaction temperature employed (120 °C). It was also revealed that ruthenium chloride as precatalyst was converted into a bromocarbonyl complex of ruthenium under the homologation conditions.
Relationship between Donor and Acceptor Numbers and Intrinsic Molecular Properties from Gas-Phase Ion Equilibria
Authors: Hiraoka Kenzo
Published: July 2006

Molecular and bulk solvent properties of protic and aprotic solvent molecules were discussed in the respects of donor numbers (DN) and acceptor numbers (AN) proposed recently by Gutmann, and the intrinsic molecular properties obtained from gas-phase ion equilibria measurements. For aprotic solvent molecules, good correlations are generally found between the gas-phase thermochemical data and both of DN and AN. This indicates that DN and AN for aprotic solvents well reflect the intrinsic molecular properties. On the other hand, the correlations for H2O and lower alcohols are not good. This is due to the more effective enhancement effect in the intermolecular interactions for protic solvents than for aprotic solvents.
Production of Cyclohexene and Reactive Sulfur Species in Vapor-Phase Catalytic Oxidative Dehydrogenation of Cyclohexane with Carbonyl Sulfide
Authors: Akimoto Masamichi , Kashita Yoshinori , Niiyama Hiroo
Published: July 2006

The vapor-phase catalytic oxidative dehydrogenation of cyclohexane with COS over SiO2 and Al2O3 catalysts (e.g., C6H12+COS→C6H10+CO+H2S) has been investigated with respect to the production of cyclohexene and cyclohexadiene as well as the mechanism of the dehydrogenation reaction. The representative value of the combined yield of cyclohexene+cyclohexadiene is 8.0% and the combined selectivity to these two products at this yield obtained is 34.0%. These values are comparable to the values 8.0 and 30.8% reported in a recent Japanese patent. The comparison of the catalytic performance between two types of flow fixed-bed reactors demonstrates that the role of solid catalysts is to decompose COS into CO and sulfur, which then dehydrogenates hydrocarbons through a homogeneous mechanism. The results of the kinetic analysis of these reactions, together with the simulation of the overall catalytic reaction system, suggest a contribution of atomic sulfur to the oxidative dehydrogenation of cyclohexane in a conventional flow fixed-bed reactor.
Spectrophotometric Determination of Gentamicin by Using a Membrane Filter Preconcentration Technique with o-Hydroxyhydroquinonephthalein and Uranium(VI)
Authors: Mori Itsuo , Fujita Yoshikazu , Fujita Kinuko , Tanaka Takeshi , Kawabe Hiroshi , Koshiyama Yozo
Published: July 2006

Color reactions among amino glycoside antibiotics such as gentamicin (GM), a metal ion such as uranium(VI), and o-hydroxyhydroquinonephthalein (Qnph) as a xanthene dye were studied by using a preconcentration technique based on membrane filtration. A simple, new, and highly sensitive spectrophotometric determination of GM has been established by using a preconcentration to collect Qnph-uranium(VI)-GM ternary complex. Beer’s law is obeyed over the range 0–5.4 μg of GM in 5 cm3 of dimethyl sulfoxide at 565 nm, and the apparent molar absorptivity for GM is 4.2×105 dm3 cm−1 mol−1 with a Sandell sensitivity of 0.0013 μg cm−2 GM at 565 nm. The procedure is about 2.5-fold as sensitive as the method employing aqueous medium, and is applicable to determination of GM in calf serum.
Comparison of ESR Signal Intensities of Some Binuclear Copper Complexes
Authors: Nakano Kunio , Tadano Hiroshi , Oshige So , Wada Nobuaki , Yamaguchi Mari , Ojima Heijiro
Published: July 2006

ESR signal intensities of two kinds of binuclear copper complex were measured by the two-step integral method with a multi-mode resonator cavity. The intensities standardized with CuSO4·5H2O are the proper values for these substances, and can be compared with each other. The intensities of oxamide type complexes (A-group) were a few tens of percent of the intensity of CuSO4·5H2O, while the intensities of binuclear complexes having a bridge of two oxygens (B-group) were less than one percent. This suggests that the two coppers in each binuclear molecule interact, and that the magnitude of the interaction of the B-group can be considered to be much greater than that of the A-group.
Thermodynamic Quantities of Transfer of Glycinato and β-Alaninato Complexes of Silver(I) and Related Species from Water to an Aqueous Dioxane Solution
Authors: Ishiguro Shin-ichi , Suzuki Honoh , Zama Masayuki , Basak Arup K , Ohtaki Hitoshi
Published: July 2006

Complexation of silver(I) with glycinate (gly−) and β-alaninate (β-ala−) ions have been studied by potentiometry and calorimetry in 0.2 mole fraction (55.0 %w/w) dioxane–water mixture containing 3 mol dm−3 LiClO4 as a constant ionic medium at 25 °C. Potentiometric titration curves obtained were well-explained in terms of formation of [AgL], [AgL2]−, and [AgHL]+ (L−=gly− or β-ala−) in both systems, together with [Ag(OH)L]− in the Ag(I)–β-alanine system, and their formation constants were determined. Enthalpies of formation of the complexes in the mixed solvent, as well as in water containing the same ionic medium, were calorimetrically determined on the basis of the formation constants potentiometrically determined. Solubilities and enthalpies of solution of the neutral [AgL] (L−=gly− and β-ala−) complexes and some related compounds were determined in water and the mixture, the Gibbs energies of transfer, ΔGt°, of silver(I) ion and proton from water to the mixture being also determined by potentiometry. By combining the thermodynamic quantities thus obtained, thermodynamic quantities of transfer of single species from water to the mixture were evaluated. Compared to the enthalpy, ΔHt°, and entropy, ΔSt°, of transfer of a neutral species, the ΔHt° and ΔSt° values of any charged species were significantly large with the negative sign for cations and positive one for anions. As to neutral species, [HL] and [AgL], the relation, ΔGt°>ΔHt°≅0 and ΔSt°<0, was found, suggesting that the [AgL] complexes have a similar zwitterionic structure to that of glycine and β-alanine zwitterions.
Adsorption of Phosphorus Oxoacid on Hydrous Titanium(IV) Oxide in an Aqueous Solution
Authors: Fujii Satoshi , Sugie Yosohiro , Sakamoto Chiaki
Published: July 2006

The adsorption behavior of phosphorus oxoacid, such as phosphinate, phosphonate, and phosphate, on hydrous titanium(IV) oxide in an aqueous solution was studied in detail. Hydrous titanium(IV) oxide has a pronounced activity for the adsorption of phosphonate and phosphate ions. However, phosphinate ion is little adsorbed on hydrous titanium(IV) oxide. The pH of aqueous solution remarkably affects the adsorption. Amounts of adsorbed phosphonate or phosphate ion from solutions of 500 mg l−1 concentration are about 0.5 mmol g−1 near pH 2. The Langmuir equation, applicable to the adsorption of phosphonate ion, has evaluated the maximum adsorption as being about 0.9 and 0.3 mmol g−1 at pHs 2 and 7, respectively. The heat of adsorption of phosphonate is −5.9 kJ mol −1 at pH 2. The adsorptive activity of hydrous titanium(IV) oxide for phosphonate is suppressed by coexisting ions, such as phosphate and anionic nickel(II) complexes.
Magnetism, Electronic State, and Local Structure of Iron-Containing Organometallic Polymers
Authors: Sugano Tadashi , Nomura Masaharu , Awaga Kunio , Kieng Poh Lee , Ohta Toshiaki , Kinoshita Minoru
Published: July 2006

Schiff-base polymers were synthesized by the reaction of 2,6-pyridinedicarbaldehyde with 1,4-butane-, 1,6-hexane-, 1,8-octane-, and 1,12-dodecanediamine. Each of the polymers, when combined with iron(II) sulfate or iron(II) chloride, exhibited anomalously large magnetization and a nonlinear relation of the magnetization curve at room temperature. These iron-containing solids were found to be amorphous and, hence, the local structures around the iron atoms in the compounds were determined by the measurements of Fe K-edge X-ray absorption spectra. It was found that the iron atoms were each surrounded by six nitrogen atoms with the almost equivalent distance of 1.93±0.02Å. This was consistent with a possible geometry in which the tridentate ligand moieties of the polymers were coordinated with the iron atoms in a ratio 2 : 1. It was also found from the results of X-ray photoelectron and Mössbauer spectroscopies that the iron atoms in the solid obtained from the reaction between poly(2,6-pyridinediylmethylidynenitrilohexamethylenenitrilomethylidyne) and iron(II) sulfate were in two valence states consisted of the high spin (S=5⁄2) irons(III) which were responsible for the observed magnetism and the low-spin (S=0) irons(II) which gave no contribution to the magnetism.
Determination of the Solvation Number of Sodium Anion in Hexamethylphosphoric Triamide
Authors: Saji Tetsuo , Aoki Katsunori , Suga Kosaku , Fujihira Masamichi , Aoyagui Shigeru
Published: July 2006

Electronic absorption spectra for saturated solutions of Na in HMPA–THF mixtures with HMPA mole fractions 0.39–0.061 exhibit only a band for Na−. A log–log plot of maximum absorbance vs. HMPA concentration has led to a numerical value 3 for the number of HMPA molecules solvating a Na− ion.
Synthesis of β-ZrClN by Thermal Decomposition of Zirconium(IV) Amide Trichloride
Authors: Ohashi Masao , Yamanaka Shoji , Hattori Makoto
Published: July 2006

The zirconium amide trichloride ZrCl3(NH2)·7NH3 was prepared by the reaction of ZrCl4 with liquid ammonia. On heating up to 600°C in flowing ammonia gas, the amide was efficiently converted into β-ZrClN, whereas under vacuum it was decomposed to a different product. The decomposition processes were followed by using a quartz spring balance.
Direct Evidence for the Peroxo Substitution of the Oxo Group in the Oxotitanium(IV) Porphyrin Complex in the Aqueous Solution
Authors: Inamo Masahiko , Funahashi Shigenobu , Tanaka Motoharu
Published: July 2006

Labeling experiments for IR and NMR spectra of oxo- and peroxotitanium(IV) complexes show that the oxo group of oxotitanium(IV) porphyrin is fully substituted by a peroxo group in the course of the reaction with hydrogen peroxide in the aqueous solution, i.e. the O–O bond of H2O2 remains intact in the peroxo complex.