bluuebunny/crossref_metadata_2025 huggingface dataset:
Syntheses of 3-Deoxy-3-C-methyl-3-nitro-d- and l-glucosides and Their Denitrohydrogenation with Tributyltin Hydride
Authors: Otani Sinichi , Hashimoto Shiro
Published: July 2006

Cyclization, with nitroethane in the presence of sodium methoxide, of the dialdehyde produced by periodate oxidation of methyl β-d-glucopyranoside and acetylation led to methyl 2,4,6-tri-O-acetyl-3-C-methyl-3-nitro-β-d- and -α-l-glucopyranoside (1, 12% and 2, 8.8%). In the case of methyl α-d-glucopyranoside, products 3 (8.6%) and 4 (8.0%) were antipodes of 1 and 2, respectively. Denitrohydrogenation of 1 or 3 with tributyltin hydride in toluene led to 3-deoxy-3-C-methyl-β-d-pyranosides (gluco, 5, 61% and allo, 6, 22%) or l-pyranosides (gluco, 9, 65% and allo, 10, 19%), respectively. This sequence of the reaction was a novel method for the syntheses of 3-deoxy-3-C-methyl-l-glucose and -l-allose. Denitrohydrogenation of 2 or 4 led to a mixture of 3-deoxy-3-C-methyl-α-l-pyranosides (allo, 7, 39% and gluco, 8, 41%) or mixture of 3-deoxy-3-C-methyl-α-d-pyranosides (allo, 11, 38% and gluco, 12, 41%), respectively. Methyl 2-O-acetyl-4,6-O-benzylidene-3-deoxy-3-nitro-β-d-glucopyranoside was denitrohydrogenated to the corresponding 3-deoxy sugar (14) in 68% yield.
Activation of Glassy Carbon Electrodes by Polishing with Ceramics Particles
Authors: Aihara Makoto , Komatsu Masahiro
Published: July 2006

Glassy carbon electrode polished with ceramics particles (TiB2, SiC, and TiC) showed higher oxidation rate of ascorbic acid. The activation seems to depend on hardness of glassy carbon and ceramics particles and to be influenced by fresh edges formed on glassy carbon surface.
Structure of Protonated Products of Potassium 1-(Dimethylamino)naphthylide
Authors: Oku Akira , Homoto Yukio
Published: July 2006

Potassium 1-(dimethylamino)naphthylide (K+DMAN\ewdot) was protonated by aqueous THF and the structures of protonated products (overall yield of three isomeric products was almost quantitative) were analyzed by 1H NMR and their 2D-NOE correlation. Products were 1-(dimethylamino)-5,8-dihydronaphthalene (major product, 88%), 7,8-dihydro- (9%), and 5,6-dihydro-isomer (3%). Deducing from the structures, the protonation pathway as well as the spin distribution in K+DMAN\ewdot is discussed.
Synthesis, Properties, and Crystal and Molecular Structure of Diaquatetrakis(thiocyanato)cobalt(II)mercury(II)-2-pyrrolidone (1/2), [CoHg(SCN)4(H2O)2]·2C4H7NO
Authors: Kinoshita Hisashi , Ouchi Akira
Published: July 2006

The title inclusion compound, which has a new-type “double decker” host skeleton, has been obtained, and its crystal and molecular structure has been determined by the X-ray diffraction technique using its single crystal. 2-Pyrrolidone molecules are not directly coordinated to any metal atoms, but are hydrogen-bonded with coordinated water-oxygen atoms in the two-dimensional polymer planes of [CoHg(SCN)4(H2O)2]n. In the complex polymer, each pair of adjacent Hg(4S(SCN) four-coordinated in a tetrahedral geometry) and Co(4N(SCN), 2O(water, trans) six-coordinated in an octahedral geometry) atoms are bridged with a thiocyanate (SCN) ion. Such two types of networks are spread approximately parallel to the (010) plane at 1/4 and 3/4 heights, and the included Lewis base molecule layers are also doubled. Compared with the previously reported single-layer host skeleton of [CoHg(SCN)4(H2O)2]·2L (L=Lewis base), the present one is short in its inter-complex layer distance, in spite of the analogous size of the included molecule. The crystallographic data are: orthorhombic, space group P21nb, a=12.004(4), b=15.330(5), c=11.985(4) Å, and Z=4. The final R value was 0.054.
The Relationships between the Formation Constants of 2,2′-Bipyridine Metal(II) Complexes and the Donor Numbers of Solvents
Authors: Abe Yuriko , Wada Goro
Published: July 2006

The complex formation constants of cobalt(II) or zinc(II) with 2,2′-bipyridine (bpy) were determined spectrophotometrically in various solvents. The values of logK1, logK2, and logK3 for the Co(II) complexes obtained were 4.06±0.06, 3.09±0.04, and 1.15±0.02 respectively in dimethyl sulfoxide, while those of logK1 for the Zn(II)–bpy complexes were 6.27±0.10, 4.14±0.01, 4.71±0.03, and 3.44±0.12 in trimethyl phosphate, N,N-dimethylformamide, N,N-dimethylacetamide, and dimethyl sulfoxide respectively. It was found that the linear relationships hold between logarithms of the formation constants of the bpy complexes and the donor numbers of the solvents when both the solvated metal ions and the bpy complexes are octahedral in the solvents.
Preparation and Structure of {Bis(3-aminopropyl)amine}(r-1, c-3, c-5-cyclohexanetriamine)cobalt(III) Complex
Authors: Ishii Minoru , Umehara Michiko , Nakahara Masayoshi
Published: July 2006

{Bis(3-aminopropyl)amine}(r-1 ,c-3,c-5-cyclohexanetriamine)cobalt(III) complex was prepared and the crystal structure of its iodide has been analyzed by X-ray diffraction. The complex cation has a facial configuration and an exo-type of N(secondary)–H bond orientation in bis(3-aminopropyl)amine. There is only a little distortion in the octahedron of this complex cation.
Favorskii-Type Rearrangement of α,α′-Dihalo Ketones Induced by Enolates of (Diethoxyphosphinyl)acetic Esters and Its Application to the Synthesis of α,α′-Divinyl Ketones
Authors: Sakai Takashi , Amano Eiichiro , Miyata Kazuyoshi , Utaka Masanori , Takeda Akira
Published: July 2006

A Favorskii-type rearrangement of 1,3-dihalo-3-methyl-2-butanone with enolate of ethyl (diethoxyphosphinyl)acetate or t-butyl (diethoxyphosphinyl)acetate gave ethyl 2-(diethoxyphosphinyl)-5-methyl-3-oxo-4-hexenoate (3a) or its t-butyl ester (3b). Compound 3b was applied to the preparation of (E)-5-methyl-1-(p-tolyl)-1,4-hexadien-3-one and diethyl (4-methyl-2-oxo-3-pentenyl)phosphonate, which are the important intermediates for natural product syntheses.
Useful Synthetic Routes to Pure exo-5-Vinyl-2-norbornene and endo-5-Vinyl-2-norbornene
Authors: Inoue Yoshiharu
Published: July 2006

Hydroboration of 5-vinyl-2-norbornene (1) with 9-BBN mainly affords 5-(2-hydroxyethyl)-2-norbornene (2). The iodo ether cyclization of 2 can convert only endo-5-(2-hydroxyethyl)-2-norbornene (2b) to iodo ether 10, followed by reductive elimination and subsequent dehydration to furnish endo-5-vinyl-2-norbornene (1b) which has not been isolated in pure form. Meanwhile, unreacted exo-5-(2-hydroxyethyl)-2-norbornene (2a) produces exo-5-vinyl-2-norbornene (1a) via dehydration.
Fluorescence Behavior and Energy Transfer of Cyanine Dyes Bound to Bilayer Membranes of Double-Chain Ammonium Amphiphiles
Authors: Nakashima Naotoshi , Ando Reiko , Kunitake Toyoki
Published: July 2006

Negatively-charged cyanine dyes are bound specifically to aqueous bilayer membranes of double-chain ammonium amphiphiles, as reflected in their absorption spectra. The quantum yield of the fluorescence emission of a trimethine-thiacyanine dye is remarkably enhanced (up to 0.64) when the dye is bound to crystalline bilayer membranes of certain double-chain ammonium amphiphiles. The fluorescence intensity diminished drastically with the liquid crystalline bilayers. Efficient energy transfer is noted from an oxacyanine to the thiacyanine dye in the crystalline membrane matrix. The efficiency decreases by the membrane phase transition to the liquid crystalline state. These results are discussed in terms of specific dye binding and concentration of dyes at the membrane surface.
The Molecular Structure of Tricarbonyl(triple-layered [2.2]paracyclophane)chromium at −95°C(Monoclinic Form) and −160°C (Triclinic Form)
Authors: Oike Hitoshi , Kai Yasushi , Miki Kunio , Tanaka Nobuo , Kasai Nobutami
Published: July 2006

The tricarbonylchromium complex of triple-layered [2.2]paracyclophane shows a reversible phase transition in the solid state from the monoclinic to the triclinic form at a temperature between −100 and −110°C. The monoclinic form crystallizes in the space group P21⁄c, with a=15.095(6), b=9.950(3), c=15.641(5) Å, β=103.46(3)° (−95°C), and Z=4: The triclinic form belongs to the space group P\bar1, with a=15.037(5) Å, b=9.913(2), c=15.662(5) Å, α=89.41(3), β=104.51(3), γ=89.39(4)° (−160°C), and Z=4. In the triclinic crystal, two molecules are crystallographically independent. The crystal structures were solved by the direct method and then refined by the block-diagonal least-squares procedure to the R indices of 0.067 for 3530 (monoclinic form) and 0.079 for 6776 (triclinic form) observed reflections. No essential difference is found between the structures of the monoclinic-form molecule and the two triclinic-form molecules. The interlayer distance between the upper-layer benzene ring coordinated to the Cr(CO)3 group and the middle-layer benzene ring is unusually shorter than the corresponding distance between the middle- and lower-layer benzene rings. No bond alternation is found in the upper-layer benzene ring, unlike as in the tricarbonyl(benzene)chromium complex and the (tricarbonyl)chromium complex of double-layered [2.2]paracyclophane. The phase transition of the crystal can be explained by a slight change in the molecular packing.
The Reaction of Dibutyl Disulfide with Hydrogen Atom
Authors: Tang Jie , Kamo Tohru , Yamada Muneyoshi , Ohshima Yozo , Amano Akira
Published: July 2006

The title reaction was investigated at room temperature and under pressures ranging from 133 to 2660 Pa. 1-Butanethiol, butane, and 1-butene were the main products. In the reaction with deuterium atom, dibutyl disulfide and 1-butanethiol were not deuterated, while butane was monodeuterated. The following mechanism was proposed to account for the product composition and its pressure dependency as well as the deuterium labeling of the products. C4H9SSC4H9+D· → n-C4H9SD +n-C4H9S·, n-C4H9S· +D· → n-C4H9SD*, n-C4H9SD*+M → n-C4H9SD, n-C4H9SD* → Δ′-C4H8+HDS, n-C4H9SD* → n-C4H9· +DS·, n-C4H9· +D· → n-C4H9D, n-C4H9· +D· → Δ′-C4H8+HD.
Association of Benzene and Alkylbenzenes with Cyclodextrins in Aqueous Medium
Authors: Sanemasa Isao , Akamine Youko
Published: July 2006

Formation constants of the following aromatic hydrocarbons with α-,β-, and γ-cyclodextrin(CyD) were determined in aqueous medium at 25°C in the presence of excess CyD : benzene, toluene, ethylbenzene, propylbenzene, isopropylbenzene, (o-, m-, and p-)xylene, and (1,2,3-, 1,2,4-, and 1,3,5-)trimethylbenzene. The technique used to study association between host(CyD) and guest (hydrocarbon) is based on the facts that the guest molecules can be driven out to gaseous phase by introducing an inert gas at a constant flow rate into the aqueous solution and that the volatilization rate of guest decreases with increasing association with the host in the aqueous solution. The 1 : 1 and 2 : 1 (host : guest) formation constants were evaluated. As a measure of hydrophobicity of guest molecules, the free energy change of dehydration derived from Henry’s law constant was used. Based on hydrophobicity and a host-guest spatial-fitting model, the formation constants have been discussed.
Topological Ligand Design. III. Parent Ligand Graphs, Simple Cage Graphs, and Donor-Atomic Graphs for the Octahedral Coordination
Authors: Takamoto Susumu , Enkaku Chikako
Published: July 2006

Various computer processes to determine all parent ligand graphs, simple cage graphs, and donor-atomic graphs for the octahedral coordination are described in order to design new sexidentate ligands. A complex ligand graph is represented by a numeral comprising of 12 figures, each of which indicates the code of a unit graph of six kinds placed on 12 edges of an octahedron. Then, 1055 parent ligand graphs, excluding chiral isomers, are selected from 612 permutations of the complex ligand graphs. A simple cage graph is produced by fusing a pair of adjacent lines around every point of an octahedral graph; 102 kinds of simple cage graphs, excluding chiral isomers, have been obtained. Another more practical method for ligand design has been proposed by starting from 62 donor-atomic graphs.
Synthesis on 1,4-Diaminocyclitol Antibiotics. IV. Synthesis of 7′-Phenylfortimicin A and 7′-Phenyl-6′-epifortimicin A
Authors: Kanai Kazuaki , Ogawa Seiichiro , Suami Tetsuo
Published: July 2006

7′-Phenylfortimicin A and 7′-phenyl-6′-epifortimicin A have been synthesized by condensation of newly prepared 1-O-acetyl-2,6-bis(2,4-dinitrophenylamino)-2,3,4,6,7-pentadeoxy-7-phenyl-l-lyxo-heptopyranose and -d-ribo-heptopyranose, respectively, with 2,5-di-O-benzoyl-1,4-bis[N-(methoxycarbonyl)]fortamine B, followed by deprotection.
Total Synthesis of 6-Hydroxy-epi-PS 5 and 6-Methoxy-epi-PS 5
Authors: Watanabe Azuma , Fukagawa Yasuo , Ishikura Tomoyuki , Yoshioka Takeo
Published: July 2006

The stabilizing effect of the 6-methoxyl or 6-hydroxyl substituent on dehydropeptidase I sensitivity of PS 5 was examined by a new total synthesis of 6-methoxy-epi-PS 5 and 6-hydroxy-epi-PS 5 from dimethyl benzyloxycarbonylaminomalonate. The Wittig reaction of α-(t-butoxycarbonyl)propylidenetriphenylphosphorane with a pyrrolidine derivative predominantly afforded a trans-α,β unsaturated ester, which was epoxidated, N-deprotected and cyclized to give a bicyclic carbapenam with a C-6 hydroxyl group. After the 6-hydroxyl group was methylated, the 2-(acetamido)ethylthio side chain was introduced at C-3 of the carbapenam by benzeneselenenylation of the geminal diester, followed by elimination of the seleninyl group. The resulting carbapenam was converted to 6-methoxy-epi-PS 5. Furthermore, 6-hydroxy-epi-PS 5 was synthesized by the use of tetrahydropyranyl and trimethylsilyl ethers for protection of the 6-hydroxyl group in a process similar to that for synthesis of 6-methoxy-epi-PS 5.
Crystal Structure of TTF·BTDA–TCNQ Complex. A New Type of CT Complex with an Inclusion Behavior and a Multi-Dimensional Structure
Authors: Suzuki Takanori , Kabuto Chizuko , Yamashita Yoshiro , Mukai Toshio
Published: July 2006

The crystal structure of TTF·BTDA–TCNQ complex was determined by an X-ray diffraction method. The crystals are monoclinic, space group P21⁄n with a=9.660(1), b=7.231(1), c=14.628(2) Å, β=91.31(1)°, and Z=2. The structure was solved by the direct method and refined by the block-diagonal least-squares method to give an R value of 0.040 for non-zero 2620 reflections. The complex is nonionic and the molecules form equally spaced mixed stacks along the b axis. These stacks are connected by strong transverse interactions resulting in a three-dimensional structure. BTDA–TCNQ molecules make cavities by S–N≡C interactions in which TTF molecules are included. This complex is not a simple CT complex with mixed stacks but rather the one with some inclusion behavior.
Halogenation Using Quaternary Ammonium Polyhalides. IV. Selective Bromination of Phenols by Use of Tetraalkylammonium Tribromides
Authors: Kajigaeshi Shoji , Kakinami Takaaki , Okamoto Tsuyoshi , Nakamura Hiroko , Fujikawa Masahiro
Published: July 2006

Reaction of phenols with calculated amounts of benzyltrimethylammonium tribromide or tetrabutylammonium tribromide in dichloromethane–methanol for 0.5–1 h under mild conditions gave, selectively, the objective mono-, di-, or tribromophenols in good yields.
Preparation of Nickel(II)–Hydroxide–(Sodium Fluoride Tetrasilicic Mica) Intercalation Complexes and Formation of Ultra Fine Nickel Particles by H2 Reduction
Authors: Ohtsuka Kunio , Suda Mitsuru , Ono Mikiya , Takahashi Minoru , Sato Minoru , Ishio Shunji
Published: July 2006

Nickel(II)–hydroxide–(sodium fluoride tetrasilicic mica) intercalation complexes were prepared by titrating nickel(II) nitrate solutions in the presence of mica with sodium hydroxide. As the degree of interlayering increased, the I(002)⁄I(001) intensity ratio increased and the specific surface areas decreased. The composition of fully developed nickel(II) hydroxide interlayer, to be exact, hydroxonickel(II) complex was [Ni3(OH)5(H2O)]+ per formula unit. Nickel(II) hydroxide within the interlayers of the silicate was reduced at about 500 °C in H2 flow and then 5–10 nm ultra fine nickel particles were distributed over the whole surface of mica. With an increase of reducing temperature, the amount of reduced nickel increased and sintering of nickel particles on the surface of mica proceeded.
Structure of Aquachloro(4-hydroxy-l-prolinato)copper(II)
Authors: Itoh Shiroo , Yukawa Yasuhiko , Inomata Yoshie , Takeuchi Toshio
Published: July 2006

An X-ray diffraction study of the title complex has been carried out. The crystal is monoclinic, with the space group P21; Z=2, a=8.712(1), b=6.055(1), c=8.187(1) Å, β=109.83(1)°. Block-diagonal least-squares refinements have led to the final R value of 0.052. The structure consists of a one-dimensional polymer chain bridged by only one carboxylato group of a 4-hydroxy-l-prolinato ligand. The chains are parallel to the b axis; each is connected with the neighboring one by hydrogen bonds between water oxygen atoms and chlorine atoms. Thus a sheet forms parallel to the (0 0 1) plane. One carboxylato oxygen atom of the 4-hydroxy-l-prolinato ligand is coordinated to two copper atoms, and the other is coordinated to one of these two copper atoms. The copper atom is surrounded by three carboxylato oxygen atoms, one water oxygen atom, one nitrogen atom in a pyrrolidine ring, and one chlorine atom. Therefore the copper atom has distorted octahedral coordination.
Mössbauer and DTA Studies of Semiconducting Potassium Vanadate Glasses Containing Iron
Authors: Nishida Tetsuaki , Takashima Yoshimasa
Published: July 2006

A Mössbauer spectrum of a series of potassium vanadate glasses containing 10 mol% Fe2O3 shows a paramagnetic quadrupole doublet, of which isomer shift proves to be smaller than 0.4 mm s−1 with respect to metallic iron. This indicates that the individual Fe3+ ion is present at the substitutional site of the V5+ (and probably V4+) ion constituting a VO4 tetrahedral unit. An increase in the K2O content of the potassium vanadate glasses results in a continuous decrease in the glass transition temperature (Tg), ranging from 239 to 200 °C, when the K2O content is changed from 5 to 30 mol%. This suggests a decrease in the coordination number of the V5+ (and V4+) ion from 5 to 4 and a formation of nonbridging oxygen atoms in the VO4 and FeO4 tetrahedral units. The formation of nonbridging oxygen atoms in the VO4 and FeO4 units is also estimated from a continuous decrease in the quadrupole splitting, suggesting a decrease in the electric field gradient at the iron nucleus and an increase in the symmetry around the Fe3+ ion. These results lead to the conclusion that the introduction of the alkali oxide (K2O) into the V2O5 results in a structural change of the V5+ (and V4+) ions from VO5 tetragonal pyramid (or trigonal bipyramid) to VO4 tetrahedral units.
13C NMR Spectra of Substituted 2-Thiophenecarboxylic Acid Methyl Esters and MNDO Calculations
Authors: Satonaka Hajime , Abe Kazuhisa , Hirota Minoru
Published: July 2006

The 13C NMR spectra have been reported on substituted 2-thiophenecarboxylic acid methyl esters. The chemical shift of ring carbons in methyl (4- and 5-substituted 2-thiophenecarboxylate)s was correlated linearly with that of the corresponding carbons in substituted thiophenes. Plots of the 13C–H coupling constants of methyl (substituted 2-thiophenecarboxylate)s against those of substituted thiophenes showed a good linear relation. The 13C NMR data were interpreted by the stable conformation and percent s character of C–H bonds obtained by MNDO calculation.
High-Pressure Kinetics of the (6+4)π Cycloaddition of Tropone with 2,3-Dimethyl-1,3-butadiene, an Acyclic Diene. The Temperature and Solvent Effects
Authors: Sugiyama Shigeru , Takeshita Hitoshi
Published: July 2006

By a high-pressure kinetic analysis in isopropylbenzene, 1,4-dioxane and N,N-dimethylformamide, the activation parameters for the (6+4)π cycloaddition reaction of tropone with 2,3-dimethyl-1,3-butadiene were determined. The findings support the concerted nature for the Woodward–Hoffmann rule-allowed thermal addition reaction of tropone. A secondary orbital interaction, which was used to predict the correct stereochemistry of the adducts, exerted no effect on the volume profile.
Solvent- and Wavelength-Dependence of the Photocleavage of the Cyclobutane Ring in N,N′-Dibutyl-c-3,c-4-bis(2-hydroxyphenyl)-r-1,c-2-cyclobutanedicarboxamide
Authors: Yonezawa Noriyuki , Kubo Masataka , Saigo Kazuhiko , Hasegawa Masaki
Published: July 2006

The ratio between two photocleavage directions of the cyclobutane ring in the title compound varies with the solvent polarity and the irradiation wavelength, and the effect of the solvent polarity appears much larger in protic solvents than aprotic ones.
Ab Initio Calculation for Interaction Potential of He–He
Authors: Ichihara Akira , Sasagane Kohtoku , Izaki Tohru , Miyazaki Tomoo , Itoh Reikichi
Published: July 2006

Using the help of an ab initio calculation with a configuration interaction (CI) treatment, the potential energy of a He dimer system could be calculated in due consideration of a correction for the basis set superposition error. In evaluating CI matrix elements, the graphical unitary group approach was adopted.
Photoacoustic in Situ Measurement of Quantum Efficiencies for Photoanodic Reactions at n-Type Semiconductor Electrodes
Authors: Yoshihara Sachio , Aruchamy Ayyasamy , Fujishima Akira
Published: July 2006

The time required for the in situ measurement of quantum efficiencies during photoelectrochemical reactions is qreatly reduced by the photoacoustic spectroscopy (PAS) employing a piezoelectric transducer (PZT). PAS has been successfully applied for several reactions at TiO2, ZnO, and CdS photoelectrodes and compared with previous studies by the photothermal spectroscopy (PTS).
Electrochemical Studies on Metal–Metal Interactions in Bismacrocyclic Ni(II) Complexes
Authors: Mochizuki Katsura
Published: July 2006

Studies on five Ni(II) complexes, i.e., 7,7′-polymethylenebis[2,12-dimethyl-3,7,11,17-tetraazabicyclo[11.3.1]heptadeca-1(17),2,11,13,15-pentaene]dinickel(II) per-chlorates with polymethylene bridges of 2–6-C length, by cyclic voltammetry and differential pulse polarography, have revealed that the half-wave potentials of the [NiIINiII]/[NiIINiIII] and [NiIINiIII]/[NiIIINiIII] couples are not changed among the hexa- to tetramethylene derivatives but shifted toward the positive side in the following order: tetramethylene<trimethylene<ethylene derivative. These results are explainable in terms of the electrostatic repulsion due to these two metal ions.
The Cyclic Voltammetry of p-Tropoquinone Acetals
Authors: Mori Akira , Hirayama Shun-ichi , Goto Yasutomo , Takeshita Hitoshi
Published: July 2006

The cyclic voltammetry of p-tropoquinone mono- and bisacetals was analyzed. Monoacetals showed an irreversible redox couple and an oxidation wave around +0.16 to −0.1 V vs. Ag/AgCl, the latter of which was due to a dianion species.
The Selective Liquid-Phase Oxidation of 3,4,5-Trimethoxytoluene to 3,4,5-Trimethoxybenzaldehyde
Authors: Kitajima Nobumasa , Takemura Kazuya , Moro-oka Yoshihiko , Yoshikuni Tadatsugu , Akada Mitsuo , Tomotaki Yoshihisa , Taniguchi Masatoshi
Published: July 2006

The selective liquid-phase oxidation of 3,4,5-trimethoxytoluene to 3,4,5-trimethoxybenzaldehyde, an important chemical intermediate for medicine production, was developed; when 2.0 mmol of the reactant was heated at 110°C for 2 h in an autoclave under 3 atm O2 with 10 ml of acetic acid in the presence of 0.75 mmol of Co(OAc)2–Mn(OAc)2 (3:1 mole ratio), a 92% yield of the aldehyde was obtained.
Solution Structure and Preferred Orientation of 3,7-Dichloro-10H-phenothiazine Dissolved in Nematic Liquid Crystal
Authors: Fujiwara Hideaki , Watanabe Masayuki , Sasaki Yoshio
Published: July 2006

1H NMR spectrum of the title compound was measured in a nematic liquid crystal ZLI1167 and analyzed utilizing modified versions of the LAOCN program. Direct couplings obtained were interpreted on the basis of a folded structure of tricyclic framework. The results show that the dihedral angle between the two benzene rings is 153.1±2.0° and the angle of S···N–H is 170.9±6.7°. Hence a “H-intra” conformation is dominant in a mobile state dissolved in the nematic liquid crystal. The preferred orientation of this molecule in ZLI1167 is discussed by comparing the results with those of the dibromo analogue reported previously and by comparing the principal axes of the order tensor with those of the moment of inertia. The chlorine and bromine atoms are supposed to exert a special steric effect on the ordering of these molecules.
Effects of Supporting Electrolyte and pH on Charge Transport within Electropolymerized Poly(o-phenylenediamine) Films Deposited on Graphite Electrodes
Authors: Oyama Noboru , Ohsaka Takeo , Chiba Kazuyuki , Takahashi Katsuhiko
Published: July 2006

The homogeneous charge-transport process within electropolymerized electroactive poly(o-phenylenediamine) (PPD) films on graphite electrodes in various supporting electrolytic solutions (i.e., NaCl, NaClO4, Na2SO4, LiCl, CF3COONa, tetraethylammonium chloride (TEACl) and sodium p-toluenesulfonate (NaPTS)) at various pH’s was examined by potential-step chronoamperometry and chronocoulometry. The overall charge-transport process was found to obey Fick’s diffusion laws and thus the apparent diffusion coefficients (Dapp) for the diffusion-like charge-transport process were estimated. The Dapp values for the oxidation and reduction processes (i.e., Dappa and Dappc) were almost the same at pH 1.0 irrespective of the thickness of PPD films and were actually independent of the supporting electrolytes except for NaPTS. As pH was increased from 1 to 7, the Dappa values decreased slightly from ca. 5.6×10−8 to 1.6×10−8 cm2 s−1 and the Dappc values did more largely from ca. 5.6×10−8 to 2.2×10−9 cm2 s−1. This behavior was essentially common to all the supporting electrolytes examined. Such pH dependences of Dappa and Dappc are discussed on the basis of the fact that the charge-transport process within PPD films involves the intrinsic electron-transfer process between adjacent electroactive sites as well as the proton addition–elimination process, the charge-compensating counterion motion, the motion of solvent and the segmental motion of the polymeric chain. Especially, it is demonstrated that in this system the proton addition–elimination process must necessarily occur in order for the charge-transport process to proceed.
Equations-of-Motion Method for the Electronic Transitions to Compound (1p-1h)+(2p-2h) States
Authors: Shibuya Tai-ichi , Funada Tadashi , Gotoh Haruo
Published: July 2006

The equations-of-motion (EOM) method proposed by Shibuya and McKoy (Phys. Rev., A2, 2208 (1970); J. Chem. Phys.  58, 500 (1973)) has been extended to include (2p-2h)-state creation and annihilation operators in the excitation operator Oλ†.
Precise Measurement of Helium Isotopes in Terrestrial Gases
Authors: Sano Yuji , Wakita Hiroshi
Published: July 2006

Helium isotope ratios of terrestrial natural gas samples were measured using a high-precision mass spectrometer and an ultrahigh-vacuum purification line. The line is equipped with a charcoal trap held at 40 K using a helium expansion refrigerating machine. To avoid interference, Ne was completely separated from He by the trap before the gas was admitted to the mass spectrometer. Ion beams of 3He and 4He were measured at the same time by a double collector system. A resolving power of about 550 at the 5% level of the peak height was attained for the complete separation of 3He ions from those of HD and H3. Precision and reproducibility of the helium isotope ratio were less than 1%, examined by repeated measurements of an air standard. Accuracy of the ratio was checked by comparing observed data with reports in the literature.
Crystal and Molecular Structure of Cobalt(II)mercury(II) Thiocyanate Adducts Having a New Layer Structure
Authors: Kinoshita Hisashi , Ouchi Akira
Published: July 2006

N-Methyl-2-piperidone adduct and dimethyl sulfoxide adduct of cobalt(II)mercury(II) thiocyanate were synthesized and their crystal and molecular structures were determined by the single-crystal X-ray diffraction technique. The former adduct is triclinic with a space group P\bar1, a=8.488(3), b=17.206(7), c=8.466(3) Å, α=103.72(1)°, β=90.00(1)°, γ=100.85(1)°, Z=2, while the latter adduct is orthorhombic with a space group P212121, a=8.418(3), b=27.389(10), c=8.407(3) Å, Z=4, and the final R values obtained were 0.059 and 0.066, respectively. In these adducts each mercury atom is in the tetrahedral geometry, coordinated with four sulfur atoms of the thiocyanate (SCN) ions, and each cobalt atom is in the octahedral geometry, coordinated with four nitrogen atoms of SCN ions and two oxygen atoms of the Lewis-base molecules which occupy the trans-positions. Each pair of different kinds of metal atoms are bridged by an SCN ion forming a 16-membered ring of Co2Hg2(SCN)4; these are linked, forming a two-dimensional network. The Lewis-base ligands are extended perpendicular to the plane on both sides. The complex layers are piled up in parallel, and there are no chemical or hydrogen bondings between the layers. This is a new type of the structure for CoHg(SCN)4L2 (L=Lewis base) type adducts.
Rotational Isomerism in Fluorene Derivatives. X. The Conformational Equilibria of 9-Substituted 9-(2-Methylthiophenyl)- and 9-Substituted 9-(2-Methylsulfinylphenyl)fluorene Derivatives
Authors: Nishida Akiko , Takamuku Michinao , Fujisaki Shizuo , Kajigaeshi Shoji
Published: July 2006

Several 9-substituted 9-(2-methylthiophenyl)fluorene derivatives and their oxidation products, 9-substituted 9-(2-methylsulfinylphenyl)fluorene derivatives were prepared. Each equilibrium constant was investigated and the conformational equilibria ap\ightleftarrowssp of these compounds were discussed on the basis of nonbonding intramolecular interactions (attraction or repulsion) between 2-substituents in phenyl moieties (methylthio or methylsulfinyl) and fluorene ring or 9-substituents. It was found that the conformational equilibria were effected by the electronic properties of methylthio and methylsulfinyl groups. Kinetic data for internal rotation of a few compounds were shown.
Synthesis of Substituted 1,3-Dienes by the Reaction of Alkenesulfonyl Chlorides with Olefins Catalyzed by a Ruthenium(II) Complex
Authors: Kameyama Masayuki , Shimezawa Hiroshi , Satoh Takeshi , Kamigata Nobumasa
Published: July 2006

Alkenesulfonyl chlorides reacted with vinylarenes in the presence of a catalytic amount of dichlorotris(triphenylphosphine)ruthenium(II) to give substituted 1:1 adducts, which were dehydrochlorinated and desulfonylated successively to form substituted (E,E)-1,3-dienes in good yield.
Studies on Lignan Lactone Antitumor Agents. IV. Synthesis of Glycosidic Lignan Variants Related to α-Peltatin
Authors: Saito Hitoshi , Nishimura Yoshio , Kondo Shinichi , Takeuchi Tomio , Umezawa Hamao
Published: July 2006

Glycosidic variants of 1-β-hydroxy-α-peltatin and 1-β-hydroxy-8-O-methyl-α-peltatin were synthesized by glycosidation of 4′,8-di-O-benzyloxycarbonyl-1-β-hydroxy-α-peltatin or 4′-O-benzyloxycarbonyl-1-β-hydroxy-8-O-methyl-α-peltatin with the corresponding glucopyranose or 2-amino-2-deoxyglucopyranose derivatives. Among synthesized compounds, cyclic acetal of 1-O-β-(β-d-glucopyranosyl)-8-O-methyl-α-peltatin showed antitumor activity in mice with leukemia L-1210.
A General Method for the Synthesis of Both Enantiomers of Optically Pure β-Hydroxy Esters from (S)-(p-Chlorophenylsulfinyl)acetone Easily Obtainable by Kinetic Resolution with Bakers’ Yeast
Authors: Fujisawa Tamotsu , Fujimura Atsushi , Sato Toshio
Published: July 2006

Both enantiomers of various optically pure (R)- and (S)-β-hydroxy esters were generally synthesized from (S)-(p-chlorophenylsulfinyl)acetone obtained by kinetic resolution with bakers’ yeast, followed by γ-alkylation, diastereoselective reduction, subsequent introduction of ester group and reductive elimination of the sulfinyl group. The key step of the diastereoselective reduction of (S)-β-keto sulfoxides was performed with diisobutylaluminum hydride to give (R)c-(S)s-β-hydroxy sulfoxides or after complexation with zinc chloride followed by addition of diisobutylaluminum hydride to give (S)c-(S)s-β-hydroxy sulfoxides which were easily separated in an optically pure form by easy crystallization or separation by silica-gel chromatography due to the p-chlorophenyl moiety in the β-hydroxy sulfoxides. The utility of the present method could be successfully demonstrated in the synthesis of both (+)- and (−)-corynomycolic acids from optically pure methyl esters of (R)- and (S)-3-hydroxyoctadecanoic acid by alkylation with tetradecyl iodide at α-position and hydrolysis.
Electron Coupled Proton Transport Mediated by [Fe4S4(SC6H4-p-n-C8H17)4]2− in Liquid Membrane
Authors: Tanaka Koji , Masanaga Mari , Tanaka Toshio
Published: July 2006

Electrochemical reduction of [Fe4S4(SC6H4-p-n-C8H17)4]2− ([4-Fe]2−) dissolved in a CH2Cl2 phase of the CH2Cl2/H2O two phase system is followed by protonation to give [4-Fe]3−–H+ when the pH of the H2O phase is lower than 7.0, and protonated and deprotonated [4-Fe]3− exist as an equilibrium mixture in the CH2Cl2 phase. On the other hand, no protonation takes place upon the reduction of [4-Fe]2− in the CH2Cl2 phase contacting with the H2O phase with the pH higher than 7.0. The electron transport conducted in a liquid membrane composed of the H2O (W1), CH2Cl2, and H2O (W2) phases containing sodium dithionite as an electron donor, (n-Bu4N)2[4-Fe] as a mediator, and disodium anthraquinone-1,5-disulfonate (Na2AQS) as an electron acceptor, respectively, revealed that protonated [4-Fe]3−–H+ mediates electron coupled proton transport in the liquid membrane, while the deprotonated cluster has no ability of electron transport in the same system.
Enhancement of Sulfation of CaO by Fe2O3 in the Oxidative-Sorption Process for SO2 Removal Using Fe2O3/CaO Binary Sorbents
Authors: Dairaku Yukinori , Sato Satoshi , Sodesawa Toshiaki , Nozaki Fumio
Published: July 2006

For the oxidative sorption of SO2 using Fe2O3/CaO binary sorbents prepared by the usual impregnation method, reactivities and capacities for SO2 removal have been investigated with TG measurements at temperatures near 500 °C in a stream of air containing SO2 in concentration from 2 to 11%. Both the reactivities and the capacities of the sorbents were exceedingly enhanced by addition of Fe2O3 into CaO such small amounts as 0.1–0.8wt%, and further Fe2O3-loading over 1.0wt% resulted in a lowering in promoting effects. The changes in surface area and pore-size distribution with a variation of Fe2O3 content were also measured in order to discuss the correlation between chemical reactivity for SO2 removal and physical property of the Fe2O3/CaO sorbents. In addition, Fe2O3–CaO mechanically mixed sorbents and the other binary sorbents such as Fe2O3/MgO or V2O5/CaO were tested to compare with the Fe2O3/CaO sorbents.
The Oxidative Polymerization of 2-Methyl-6-(3,7-dimethyl-2,6-octadienyl)phenol
Authors: Hyun Sang-Heon , Nishide Hiroyuki , Tsuchida Eishun , Yamada Shigetoshi
Published: July 2006

2-Methyl-6-(3,7-dimethyl-2,6-octadienyl)phenol (MGP) was prepared by the reaction of o-cresol and 1-chloro-3,7-dimethyl-2,6-octadiene in the presence of sodium. This MGP was then oxidatively polymerized with a copper-pyridine catalyst to yield poly[oxy[3-methyl-5-(3,7-dimethyl-2,6-octadienyl)-1,4-phenylene]]. The MGP and 2,6-dimethylphenol (DMP) copolymerized with a similar reactivity to form copolymer. The properties of the polymers were also studied.
Gamma-Irradiation Effect on the Catalytic Behavior of Binary Oxide Catalysts
Authors: Hassan E A , Abd El-Salaam K M , Said A A
Published: July 2006

Decomposition of hydrogen peroxide in aqueous solution was used for testing the effect of gamma radiation on the catalytic activity of CoxFe3−xO4, with O≤x≤3.0. The activity variation was interpreted in terms of the catalysts electronic structure. The presence of Co2+ on octahedral sites is superior to Fe2+ in the catalytic process. However, γ-irradiation can produce a considerable effect on the catalytic activity due to its influence on the active site concentration and cation distribution.
Charge-Transfer Complexes of Nitrones. VI. Molecular Complexes of Nitrones with Iodine
Authors: El-Din Ahmed M Nour , Tawfik Abdel-Razak
Published: July 2006

Charge-transfer (CT) complexes between some α-aryl and α-(heterocyclic substituted)nitrones and iodine as σ-acceptor in dichloromethane have been investigated spectrophotometrically. From the energies of the charge-transfer transitions, the ionization potentials of the nitrones have been obtained. The stoichiometry of the complexes has been determined. All the results are in agreement with the n–σ* nature of these complexes with some involvement of the π-orbital of the donor.
Peroxy Acid Oxidations. II. A Kinetic and Mechanistic Study of Oxidation of α-Diketones
Authors: Panda Radhasyam , Panigrahi Akhil Krishna , Patnaik Chakrapani , Sahu Sabita Kumari , Mahapatra Sabita Kumari
Published: July 2006

The kinetics of Baeyer-Villiger oxidation of biacetyl and benzil by peroxomonophosphoric acid and peroxomonosulfuric acid have been studied in different pH ranges at 308 K. The reactions are second order; first order each in peroxy acid and in diketone concentrations at constant pH. The oxidation rate is strongly pH-dependent; the rate increases with increase in pH. From the pH-rate data the reactivity of different peroxo species, in the oxidation, has been determined. A mechanism consistent with rate-determining nucleophilic attack of peroxo species on carbonyl carbon of the diketone molecule has been proposed. Acetic acid and benzoic acid are respectively found to be the products of oxidation of biacetyl and benzil.
Nitriles in Organic Synthesis. The Chemical Behavior of [1-(2-Furyl)-ethylidene]- and [1-(2-Thienyl)ethylidene]malononitriles
Authors: El-Maghraby Mohamed Abdallah , Sadek Kamal Usef , Selim Maghraby Ali , Elnagdi Mohamed Hilmy
Published: July 2006

The chemical behavior of [1-(2-furyl)ethylidene]- and [1-(2-thienyl)ethylidene]malononitriles 1a and b toward electrophilic reagents, active methylene reagents and (arylmethylene)malononitriles is described.
Reaction Network for Selective Oxidation of Propene on a (Mo–Pr–Bi)O/SiO2 Catalyst
Authors: López Nieto J M , Tascón J M D , Kremenic G
Published: July 2006

Oxidation of propene on a Mo4Pr0.5Bi0.5Ox/SiO2 catalyst was studied in order to establish the reaction network. In the temperature range 598–653 K the primary reaction products were propenal (main product), acetone, acetaldehyde, and carbon dioxide. Other products (mainly aldehydes and acids) could be classified as secondary reaction products. From studies of oxidation of the primary unstable products and the kinetics of formation of minor primary products it is concluded that both, acetaldehyde and carbon dioxide, are formed through parallel and consecutive reactions. Acetone formation is strongly influenced by reaction temperature, probably due to changes in the active centers of the catalyst.
35Cl NQR Study and Addition Reactions to Cyclohexene of Cyclic N-Chloro Amides (Imides)
Authors: Nagao Yoshitaka , Katagiri Shigeyoshi
Published: July 2006

35Cl NQR frequencies were measured for N-chloro-2-pyrrolidinone, N-chloro-4,4-dimethyl-2-oxazolidinone, N-chloro-2-oxazolidinone, N-chloroglutarimide, and N-chlorosuccinimide. The ionicities of the N–Cl bonds were estimated on the basis of those measurements. These ionicities were related to the total yields of the 1,2-addition in the photochemical reaction with cyclohexene. When the value of the ionicity neared zero, the total yield increased.
Optical Resolution of α-Ethylbenzylamine and Its Application as a Resolving Agent
Authors: Nohira Hiroyuki , Nohira Misako , Yoshida Shin-ichi , Osada Ayako , Terunuma Daiyo
Published: July 2006

(±)-α-Ethylbenzylamine ((±)-1) was efficiently resolved into a pair of enantiomers by fractional crystallization as its cis-2-benzamidocyclohexanecarboxylic acid (2) salt. Moreover, it was found that each of both enantiomers was obtained by mutual resolution between (±)-1 and (±)-2. The optically active amine (1) was substantially capable of resolving a variety of chiral carboxylic acids.
Polarographic and Cyclic Voltammetric Reduction of p-Chlorobenzaldehyde Isonicotinoylhydrazone
Authors: Reddy Papammagari Raveendra , Rao Sukuru Brahmaji
Published: July 2006

p-Chlorobenzaldehyde isonicotinoylhydrazone (p-Cl-BAINH) exibits a single wave in acid buffered solutions (pH 2–6) and two waves in alkaline buffered solutions (pH 7–9). However, the compound exhibits three cathodic peaks in acid solution and two cathodic peaks in alkaline solutions. The electrode reactions are attributed to the reductive cleavage of =N–N– linkage and the reduction of the amide formed in the cleavage.
Temperaturabhängigkeit der Fluoreszenz von Gd3+ in Wässriger Lösung
Authors: Baumann Markus
Published: July 2006

The effects of pressure and temperature on the fluorescence of aqueous Gd3+ solution have been studied, the following results being obtained: (a) The pressure up to 100 MPa gives no influence on emission, (b) The fluorescence diminishes with temperature rise, nearly disappearing at 200 °C.
Ring Size Effect on [2+2] Photochemical Cycloaddition of Enones with Cyclic Olefins
Authors: Tada Masahiro , Nieda Yuuki
Published: July 2006

Photochemical reaction of 3-substituted 2-cyclohexen-1-ones with methyl 1-cyclohexene-1-carboxylate gave only head-to-tail, cis-transoid-cis photoadduct. The photoadducts of 3-methyl-2-cyclohexen-1-one with methyl 1-cyclopentene-1-carboxylate and with methyl 1-cyclobutene-1-carboxylate had head-to-head, cis-transoid-cis ring systems.
The Structure of Galantinamic Acid, a New Amino Acid in a Peptide Antibiotic Galantin I
Authors: Wakamiya Tateaki , Terashima Shin-ichi , Kawata Mitsuyasu , Teshima Tadashi , Shiba Tetsuo
Published: July 2006

A new amino acid named galantinamic acid was found as one of the constituent amino acids in a peptide antibiotic galantin I. The primary structure of galantinamic acid was determined chemically and spectrometrically to be 6,10-diamino-2,3,5-trihydroxydecanoic acid.
Asymmetric Catalytic Hydrogenations of Oximes and Benzylimino Derivatives of Chiral Pyruvamides
Authors: Munegumi Toratane , Harada Kaoru
Published: July 2006

Oximes and benzylimino derivatives of chiral pyruvamides were hydrogenated over palladium hydroxide on charcoal in several solvents. Oximes of pyruvamides containing (R)-α-ethylbenzylamine as a chiral source gave (S)-alanine in excess (up to 70% e.e.) through the hydrolyses of the hydrogenated products.
The Photocyclization of N,N-Dialkyl β-Oxo Amides on Silica Gel
Authors: Hasegawa Tadashi , Moribe Jun-ichi , Yoshioka Michikazu
Published: July 2006

β-Oxo amides 1 adsorbed on silica gel underwent photocyclization via δ-hydrogen abstraction to give the five-membered lactams 2. No severe restrictions on the molecular motion could be observed in the photoreaction on the silica-gel surface. However, the relative photoreactivity of N,N-dibenzyl-2-benzoylacetamide (1a) to N,N-dibenzyl-2-benzoylpropionamide (1b) increased greatly on the silica-gel surface compared to that in solution, probably because of the greater keto content on the surface.
NQR of 35Cl, 127I, and 121Sb in I3Cl2SbCl6 and ICl2SbCl6
Authors: Mishima Mitsuo , Okuda Tsutomu
Published: July 2006

NQR spectra due to 35Cl, 127I, and 121Sb in I3Cl2SbCl6 and ICl2SbCl6 have been observed in the temperature range 77 K to melting point. The Zeeman effect on the single crystals of these complexes has been examined. In I3Cl2SbCl6 the η-values for the I atoms contributing to the higher and the lower NQR frequencies are 0.73 to 0.09, respectively, whereas in ICl2SbCl6 the η-value for the I atom is 0.15. In these complexes the 35Cl NQR lines which yield large η-values (0.42 to 0.56) are assigned to the bridging Cl atoms. The η-values for the other Cl atoms, except the Cl atoms in the ICl2+ ion which have η-values of 0.13 to 0.15, are negligibly small. The Sb atoms in both complexes have considerably large η-values (0.39). The orbital populations have been calculated from the NQR parameters. The bonding in the cations is explained on the basis of an approximation using only p orbitals of the I atom.
Hydrodynamic Characterization of Amylose–SDS Complex by Viscosity Measurement
Authors: Yamamoto Masako , Harada Shoji , Nakatsuka Thoru , Sano Takayuki
Published: July 2006

The hydrodynamic behavior of amylose with and without sodium dodecyl sulfate (SDS) has been examined by viscosity measurements. Two distinct viscosity phenomena have been observed by complexation; one is the increase at the first stage of binding of SDS, which disappears by an addition of salt, and the other is the subsequent decrease in the region of further binding of SDS. These results are interpreted by an idea that the expansion of the complex occurs by an electrostatic repulsion of the bound SDS molecules and the contraction of the complex by a hydrophobic interaction of cooperatively bound SDS molecules. This idea was confirmed further by experiments using amyloses of different length and homologous surfactants of SDS.
Preparation of SnO2 and Nb2O5 Supported Vanadium Oxide Catalysts by a Column-Exchange Adsorption Method and Dispersed States of Vanadia Species
Authors: Kera Yoshiya , Kawashima Takahiro
Published: July 2006

SnO2 and Nb2O5-supported monolayer or sub monolayer vanadium oxide catalysts were prepared by an impregnation method such as the column-exchange adsorption of oxovanadium ion at various pH(=2, 4, and 7). The deposited states of the vanadia species on SnO2 and Nb2O5 surfaces were examined by ESR spectrometry using V4+ ion as a probe. The catalytic features were studied by measuring the 2-propanol decomposition rate as a test reaction. The deposited states of the vanadia species differed to a small extent between SnO2 and Nb2O5 carriers depending upon the difference in the symmetry of the surface field. The deposited states, however, did not vary with pH upon impregnation, although the amounts of vanadium oxide deposited (coverage, θ) were much affected by the pH. The activation energy (Ea) for the dehydration of 2-propanol over these catalysts was linearly related to the reciprocal of the coverage (1⁄θ). When both curves were extended to 1⁄θ=0, they crossed at around 5–6 kcal·mol−1 which was the minimum value, although the inclination differed largely between the carriers. This low activation energy was regarded as an intrinsic value that was caused by the multi-layered vanadium oxide deposited on the carriers. Through the discussion it is clearly shown that the most effective catalyst, a monolayer catalyst, was prepared on impregnation at pH=2 and the vanadia species were dispersed widely, keeping a weak interaction with the SnO2 and Nb2O5 surfaces.
The 1H and 13C NMR of 9,10-Bis(phenylethynyl)anthracene Dianion
Authors: Hirayama Masatoshi , Kobayashi Masaaki , Yamamoto Hiroshi
Published: July 2006

The formation of 9,10-bis(phenylethynyl)anthracene dianion by contact of tetrahydrofuran-d8 solution of its precursor with sodium in vacuo, is confirmed by the 1H and 13C NMR spectra and its reactivity. The excess π-charge-density distribution estimated by the CNDO/2 calculation for the dianion, is consistent with the observed 1H and 13C chemical shift values.
Adsorbing-Particle Flotation of Hg2+ by Combined Use of Charcoal, Polyacrylamide, and Cationic Surfactant
Authors: Kidokoro Tadahiko , Matsui Kotaro , Ishiwata Satoshi , Sasaki Toshiyuki , Sasaki Tsunetaka
Published: July 2006

Adsorbing-particle flotation of Hg2+ ions by using active charcoal as an adsorbent, Polyacrylamide (PAA) as a coagulant, and hexadecyltrimethylammonium chloride (HTAC) as a frother was carried out. The floatability exceeded 90% in a wide range of pH and nearly 98% of Hg2+ ions was floated from 2.1×10−4 mol dm−3 solution by adding 2500 ppm of active charcoal, 24 ppm of PAA, 81 ppm of HTAC and with shaking. Stepwise and double flotations were further attempted which proved to distinctly increase the floatability, while sodium sulfide treatment of active charcoal showed only a slight increase and the coexistence of chloride ions showed no effect. The mechanism of adsorbing-particle flotation was discussed.