bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthetic Studies on the Validamycins. XII. Synthesis of Optically Active Valienamine and Validatol
Authors: Ogawa Seiichiro , Shibata Yasushi , Nose Taisuke , Suami Tetsuo
Published: July 2006

(+)-Valienamine and (+)-validatol have been totally synthesized as the peracetyl derivatives starting from a common synthetic intermediate, (1S)-(1,3/2)-4-methylene-5-cyclohexene-1,2,3-triol.
Chemistry of N-Nitrososulfonamides. Substitution Reaction by the Acetyl Group
Authors: Iwata Masaaki , Kuzuhara Hiroyoshi
Published: July 2006

The N-nitroso group on N-nitrososulfonamides was substituted for the acetyl group in chloroform to give N-acetylsulfonamides in moderate yields.
The 1-Octanol/Water Partition Coefficient of Mercury
Authors: Okouchi Shoichi , Sasaki Sokichi
Published: July 2006

The 1-octanol/water partition coefficient of metallic mercury was measured as a useful parameter for predicting the environmental behavior or fate of mercury. The partition coefficient obtained was 4.15±0.20 at 298 K; it slightly decreased from 4.80 to 3.80 as the temperature rose from 278 to 308 K. The partition coefficient of metallic mercury is very low in comparison with those of such nonpolar organic compounds as benzene and tetrachloromethane. Therefore, it was found that metallic mercury has a tendency to be further concentrated in the atmosphere.
Reaction of Malonaldehyde with Nucleic Acid. II. Formation of Fluorescent Pyrimido[1,2-a]purin-10(3H)-one Mononucleotide
Authors: Seto Hiroshi , Takesue Tomoyuki , Ikemura Tadashi
Published: July 2006

The reaction of malonaldehyde under acidic conditions (pH 4.5) with guanosine 5′-monophosphate resulted in the formation of fluorescent 3-(β-d-ribofuranosyl)pyrimido[1,2-a]purin-10(3H)-one 5′-phosphate (3a). This adduct was also isolated from malonaldehyde-reacted RNA. The amount of 3a in the modified RNA was estimated to be 0.4 per cent by weight. The fluorescence spectrum of 3a (Ex max. 360 nm, Em max. 500 nm) was similar to that of guanine- and guanosine-malonaldehyde adducts which have the same type base structure. On the other hand, another type of fluorophore (Ex max. 390 nm, Em max. 460 nm) was also formed in the reaction of malonaldehyde with a nucleic acid polymer. Thus, at least two different types of fluorophores are present in malonaldehyde-reacted nucleic acid.
Total Synthesis of Antibiotic Althiomycin
Authors: Inami Kaoru , Shiba Tetsuo
Published: July 2006

Total Synthesis of antibiotic althiomycin has been achieved starting from d-cysteine. The imide bond between thiazoline and the pyrrolinone part was constructed by coupling reaction of sodium salt of pyrrolinone with cysteine active ester or by photoreaction with diketene. The hydroxymethyl group attached on the carbon adjacent to C-2 of the thiazoline ring, was introduced by aldol condensation posterior to the thiazoline ring formation. The thiazole part was introduced in a final step in whole process of the total synthesis of the antibiotic. The synthetic althiomycin was identical with the natural antibiotic in all respects.
Preparation of Polyoxa- and Dioxapolythia[n](1,1′)ruthenocenophanes and Their Metal Complexes
Authors: Habata Yoichi , Akabori Sadatoshi , Sato Masaru
Published: July 2006

Polyoxa- and dioxapolythia[n]ruthenocenophanes were prepared by the reaction of 1,1′-diacetoxyruthenocene with α-(2-bromoethyl)-ω-bromopoly(oxyethylene) in the presence of alkali metal hydroxides and by the reaction of 1,1′-bis(2-chloroethoxy)ruthenocene with dithiolate in the presence of sodium hydroxide, respectively. The extraction ability of their compounds was excellent for mercury(II) and thallium(I) ions. The ruthenocenophanes with oxygen atoms attached to the ruthenocene nucleus showed excellent extraction ability for a silver(I) ion, although the corresponding ferrocenophane analogs decomposed in similar reaction conditions. The ruthenocenophanes formed 1 : 1 complexes with mercury(II) and silver(I) ions. 1H-NMR, electronic, and IR spectral data of their complexes showed the presence of direct electronic interaction between the mercury(II) or silver(I) ion and the ruthenium atom of ruthenocenophanes.
Electrodeposition of Catalytically Active Cobalt Powder from Aqueous Sulfate Electrolytes
Authors: Abd El-Halim A M , Khalil Reda Mohamed
Published: July 2006

The electrodeposition of cobalt powder was investigated from aqueous sulfate solutions containing 0.0125–0.0500 CoSO4·7H2O (I), 0.23–1.00 (NH4)2SO4 (II), 0.1 H3BO3 and 0.07 mol dm−3 Na2SO4·10H2O. The effects of the bath composition, the pH, the deposition current density and the duration of electrolysis on the cathodic polarization and the efficiency of cobalt electrodeposition, as well as on the morphology and the catalytic activity (towards the decomposition of 0.4% H2O2 solution) of the as-deposited cobalt powders were discussed. X-Ray diffraction studies proved that cobalt powders were very pure and deposited in the hexagonal close-packed structure with the orientations (100), (002), and (101). Cobalt powder deposited with an efficiency of 32% and had a catalytic activity approaching 100% could be obtained from the above-mentioned bath formula containing 0.05 mol dm−3 (I) and 0.46 mol dm−3(II). The optimum operation conditions to achieve these characteristics were: pH 4.78, j=10A dm−2 and t=15 min.
Laser Photolysis Study on the Duroquinone-photosensitized Isomerization of Stilbenes in Micellar Solution
Authors: Tanimoto Yoshifumi , Takayama Masanari , Shima Sayaka , Itoh Michiya
Published: July 2006

Photoinduced electron-transfer reaction between the excited triplet duroquinone and trans- and cis-stilbenes generates trans-stilbene cation radical in SDS micellar solution, suggesting that the cis-trans isomerization of stilbene occurs via an electron-transfer mechanism.
Ring Transformation of 1,4 (or 1,6)-Disubstituted 3,5-Dinitro-2-pyridones with Sodio β-Keto Esters
Authors: Ariga Masahiro , Tohda Yasuo , Matsumura Eizo
Published: July 2006

The ring transformation of 1,6-dimethyl-, 1,4-dimethyl- and 4-methoxy-1-methyl-3,5-dinitro-2-pyridones with sodio β-keto esters to nitrosalicylic esters was investigated concerning the electronic effects of 4 and 6-substituents. The results were explained by the HSAB principle.
59Co Quadrupole Effects on the 1H, 31P, and 59Co NMR Spectra of HFeCo3(CO)9[P(OCH3)3]3 and the 1H NMR Spectra of Other Derivatives
Authors: Saito Taro , Sawada Satoshi
Published: July 2006

The 1H NMR spectra of HMCo3(CO)12 (M=Fe or Ru) and HFeCo3(CO)12−x[P(OR)3]x (x=1–3, R=CH3; x=3, R=C2H5 or C6H5) showed very broad signals centered near δ=−21 at 27 °C. The band widths were generally smaller for the compounds of larger molecular volume, at lower temperatures and with higher viscosity of the solvent. These data were interpreted in terms of the quadrupole effects of 59Co nuclei to which the hydride proton was μ3-bonded. Supporting evidence was obtained from the 31P and 59Co NMR spectra and the relaxation time T1 of HFeCo3(CO)9[P(OCH3)3]3.
Synthesis of Hg(II) Complexes of Cysteine-Containing Oligopeptides
Authors: Ueyama Norikazu , Nakata Michio , Nakamura Akira
Published: July 2006

Tetrapeptides, Z–Cys–Ala–Ala–Cys–OMe(Z=benzyloxycarbonyl), Z–Cys–Val–Val–Cys–OMe, and Z–Cys–Gly–Pro–Cys–OMe, having Cys–X–Y–Cys sequences were synthesized by using an acetamidomethyl (Acm) protecting group. The Hg(II) complexes of these peptides, Hg2Cl2(Z–Cys–Ala–Ala–Cys–OMe) 1. Hg(Z–Cys–Ala–Ala–Cys–OMe) 2, Hg2Cl2(Z–Cys–Gly–Pro–Cys–OMe) 3, Hg(Z–Cys–Val–Val–Cys–OMe) 4, and Hg2Cl2(Z–Cys-Ala-Cys–OMe) 5 were synthesized by the reaction of the S(Acm) protecting peptides and HgCl2 in N,N-dimethylformamide. Two Raman bands due to Cl–Hg–S of 1, 3, or 5 were observed at 314, 281, or 276 cm−1 in solid, whereas a single band due to S–Hg–S was found at 326 cm−1 for 2 or 327 cm−1 for 4, in solid.
Selective Hydrogenation of Cyclooctadienes Using Colloidal Palladium in Poly(N-vinyl-2-pyrrolidone)
Authors: Hirai Hidefumi , Chawanya Hitoshi , Toshima Naoki
Published: July 2006

Selective hydrogenation of 1,3-, 1,4-, and 1,5-cyclooctadiene to cyclooctene was carried out at 30 °C under atmospheric hydrogen pressure using colloidal palladium which was prepared by reducing palladium(II) chloride with refluxing methanol in the presence of poly(N-vinyl-2-pyrrolidone). The yields of cyclooctene were 99.9% and 97.8% for hydrogenation of 1,3- and 1,5-cyclooctadiene, respectively at the point that an equimolar hydrogen was uptaken by cyclooctadienes. The hydrogenation rate of 1,3- and 1,4-cyclooctadiene (R1) is expressed as R1=k1[H2][Pd], and that of 1,5-cyclooctadiene (R2) is expressed as R2=k2[H2]0.7[Pd], where k1 and k2 are the rate constants. Alcohols were found to be good solvents for hydrogenation. In particular the fastest rate and the highest selectivity for monoene were observed in methanol among the solvents examined. Effect of bases on the monoene selectivity has also been investigated.
Characterization of 13-Hydroxyneocembrene from Soft Corals
Authors: Aoki Mario , Kato Tadahiro , Uchio Yasuto , Nakayama Mitsuru , Kodama Mitsuaki
Published: July 2006

The isolation and structural elucidation of 13-hydroxyneocembrene from soft corals were carried out.
The Thermal Cis-to-trans Isomerization of N,N′-Diacylindigos. Kinetic Pressure, Solvent, and Substituent Effects
Authors: Sueishi Yoshimi , Ohtani Kazuo , Nishimura Norio
Published: July 2006

The kinetics of the thermal cis-to-trans isomerization of N,N′-diacylindigos(DAI) in various solvents and under high pressures has been studied. N,N′-Dibenzoylindigos(DBI) isomerize about 10 times slower than molecules not having a benzene ring in the acyl groups. The values of the activation volumes were about 8.0 cm3 mol−1 for the former and about 3.0 cm3 mol−1 for the latter. It was suggested that the thermal isomerization proceeds via the biradical mechanism. The positive values of the activation volume have been interpreted in terms of the increase in the intrinsic volume upon activation. The differences in the isomerization rates and the activation parameters between DBI and the others have been ascribed to an additional interaction between the two phenyl rings in the acyl groups in the cis-ground state.
Studies on the G(Fe3+→Fe2+)-value in the Radiolysis Caused by 6Li(n,α)T Reaction in Lithium Tris(oxalato)ferrate(III)
Authors: Akashi Junko , Kojima Tomoko , Uchida Yoshio , Sano Hirotoshi
Published: July 2006

The G-values for the reduction of iron(III) to iron(II) state caused by 6Li(n,α)T reaction in Li3[Fe(C2O4)3]·4.5H2O and in anhydrated Li3[Fe(C2O4)3] were determined by taking into account the saturation of the effect of increasing neutron fluence. The contribution of the fast neutrons and γ-rays in a nuclear reactor to the reduction was estimated by using a cadmium tube, and by using the results estimated in the 60Co γ-ray irradiation, respectively. The G(Fe3+→Fe2+)-value in the radiolysis caused by 6Li(n,α)T reacation in Li3[Fe(C2O4)3]·4.5H2O is larger than that in the γ-ray radiolysis, and is also larger than the G-value for anhydrated Li3[Fe(C2O4)3], suggesting that the radiolysis of the water of crystallization contributes to the reduction of the iron(III) species.
Isomerization of Allylic Alcohols Catalyzed by Vanadium or Molybdenum Complexes
Authors: Matsubara Seijiro , Okazoe Takashi , Oshima Koichiro , Takai Kazuhiko , Nozaki Hitosi
Published: July 2006

Isomerization of primary allylic alcohols proceeds in dichloromethane at 25 °C in the presence of the catalyst prepared in situ from VO(acac)2 or MoO2(acac)2, and Me3SiOOSiMe3 to give tertiary isomers in good yields. The catalysts are also effective for the rearrangements of sec.→tert. allylic alcohols. The isomerization of an allenyl allylic alcohol, 6-methyl-1,2,5-heptatrien-4-ol, gives either (E)-2-methyl-3,5,6-heptatrien-2-ol or (E)-6-methyl-3,5-heptadien-2-one selectively depending on the reaction conditions.
Structural, Magnetic and IR Spectroscopic Characterization of Dimeric Copper(II) Trichloroacetate Adduct with Benzonitrile. Nature of the Copper(II)–Bezonitrile Bond
Authors: Nakashima Michio , Mikuriya Masahiro , Muto Yoneichiro
Published: July 2006

The benzonitrile adduct of copper(II) trichloroacetate, [Cu(Cl3CCOO)2(PhCN)]2, was prepared and characterized. The dimeric structure was confirmed by an X-ray structural determination. This compound crystallizes in the triclinic space group P\bar1 with a=12.780(1), b=16.064(1), c=10.130(1) Å; α=108.39(1), β=113.34(1), γ=81.07(1)°. The crystal consists of two crystallographically independent dimeric units. Both units have the familiar dimeric copper(II) acetate monohydrate structure with Cu–Cu distances of 2.731(1) and 2.732(1) Å. Magnetic susceptibility data in the range of 80–300 K are well represented by the usual dimer equation with a singlet-triplet energy separation of −2J=224 cm−1. The C≡N stretching frequency of benzonitrile in the compound shows an increase by 31 cm−1 from the free ligand value. On the basis of the X-ray crystallographic and IR spectroscopic results, the nature of the copper(II)–benzonitrile bond is discussed. For discussion magnetic and spectroscopic properties of some analogous nitrile adducts of copper(II) chloroacetates were also studied.
Synthetic Inorganic Ion-exchange Materials. XXXVII. Ion-exchange Behaviors of Alkylammonium Ions on Hydrous Titanium Dioxide
Authors: Tsuji Masamichi , Abe Mitsuo , Orimo Minoru
Published: July 2006

Ion-exchange behavior of alkali hydroxide and alkylamines having different sizes and forms on hydrous titanium dioxide ion exchanger (HTDO) were studied. The uptakes of all the cations by HTDO indicated the ion-exchange stoichiometry at a pH range studied. The pH titration curves vary, depending on the cation species and the strength of the bases used: amorphous HTDO(Am-HTDO) behaves as a bifunctional acid towards strong bases and as a monofunctional acid towards weak bases. Am-HTDO shows an affinity series in the increasing order: large ions((C2H5)3NH+, (CH3)4N+, and (n-C4H9)4N+)<ions in medium size (CH3NH+, n-C3H7NH3+, n-C4H9NH3+  etc.)<small ions(Na+, K+, and NH4+). The large ions suffer from a strong steric effect, because of the limited space of the ion-exchange site available. The results correlate with the pore size distribution: the pore radius ranged from 4 to 7 Å in Am-HTDO degassed at 40 °C by a rotary pump. The maximum volume occupied by the alkylammonium ions exchanged (0.2–0.3 cm3/g), calculated by assuming cations to be unhydrated, is in good agreement with the value determined by N2 gas adsorption (0.16 cm3/g). An anatase-type HTDO showed a larger steric effect for uptake of the alkylammonium ions than that by the Am-HTDO, due to a decrease in the ion-exchange cavity.
The Syntheses of the Corticoid Side Chain. I. An Improved Method for the Preparation of 17α-Hydroxyprogesterone from Androst-4-ene-3,17-dione
Authors: Nitta Issei , Fujimori Shinichiro , Ueno Hiroaki
Published: July 2006

The 17β-cyano-17α-hydroxyandrost-4-en-3-one can be prepared from androst-4-ene-3,17-dione in an excellent yield. This derivative can be converted into 17α-hydroxyprogesterone, an intermediate of corticosteroids.
The Syntheses of the Corticoid Side Chain. III. A New Synthesis of 17α,21-Dihydroxypregna-1,4-diene-3,20-dione 17,21-Diacetate from Androsta-1,4-diene-3,17-dione
Authors: Nitta Issei , Fujimori Shinichiro , Haruyama Toshio , Inoue Shinya , Ueno Hiroaki
Published: July 2006

An efficient synthesis of 17α,21-dihydroxypregna-1,4-diene-3,20-dione 17,21-diacetate (10) from androsta-1,4-diene-3,17-dione (1), a biodegradation product of cholesterol, is described, which involves the ethynylation of the 17-ketone, the epimerization of the 17α-ethynyl group and conversion of the ethynyl group to the 20-keto pregnane. Overall yield is relatively high (about 54%) and 10 will be a potential intermediate for prednisolone.
An X-Ray Diffraction Investigation of the Coordination Structure of Mn(II) Ions in Highly Concentrated Aqueous MnBr2 and MnCl2 Solutions
Authors: Tajiri Yoshichika , Ichihashi Mitsuyoshi , Mibuchi Takeharu , Wakita Hisanobu
Published: July 2006

The solute structures of highly concentrated aqueous 5.087 and 2.744 mol dm−3 MnBr2, and 4.744 and 2.732 mol dm−3 MnCl2 solutions were determined by the analysis of the radial-distribution function curves of X-ray diffraction experiments. Mixed-ligand aquahalogenomanganese(II) complexes were found to be present in these solutions, holding a distorted octahedral geometry. The interatomic distances of the aquabromo complex are 2.178–2.184 Å for Mn–OH2 and 2.596–2.643 Å for Mn–Br; those of the aquachloro complex are 2.183–2.185 Å for Mn–OH2 and 2.492–2.496 Å for Mn–Cl. The interatomic distances of Mn–OH2 are shorter than those of the MnBr2·4H2O and MnCl2·4H2O crystals and are consistent with those of the Mn(OH2)6(NO3)2 crystal. The length of the Mn–Cl bond here determined is practically the same as that within the MnCl2·4H2O crystal, but the Mn–Br bond found is shorter than that within the MnBr2·4H2O crystal. The average coordination number of the Mn–Br contact per Mn(II) increased from 1.104 to 1.212 with an increase in the Br/Mn ratio from 2.076 to 3.269, while the number of the Mn–Cl contact per Mn(II) increased from 1.259 to 1.501 with an increase in the Cl/Mn ratio from 2.000 to 3.352. In all solutions, the aquamonohalogeno and aquadihalogeno complexes exist as the main species, but the aquadihalogeno complex is more dominant in the MnCl2 solution than in the MnBr2 solution.
Reciprocal Space Expansion in the Analysis of X-Ray Scattering Intensities from Liquid Carbon Tetrachloride
Authors: Nishikawa Keiko , Iijima Takao
Published: July 2006

The concept of “reciprocal space expansion” has been applied in the analysis of the X-ray scattering intensity from liquid carbon tetrachloride. The results obtained by using the bcc local lattice structure model show very good agreement with the experimental intensity in the small-s region, where ghost peaks are inevitably introduced by the “real space expansion” usually adopted.
The Studies on the Hydration Energy and Water Structures in Dilute Aqueous Solution
Authors: Moon Myung Jun , Jhon Mu Shik
Published: July 2006

Thermodynamic properties of dilute aqueous solutions are influenced by the interactions between ions and water molecules as well as the change of the water structure around the ion. To obtain hydration energies of monoatomic ions and local water structures around the ions, we make use of the discrete-continuum method. The calculated values for the hydration energies of ions are in good agreement with experimental values. The hydration energies of monoatomic cations can be qualitatively correlated with the sum of the successive ionization potentials from its atomic state to the ionic state. From their correlations, we can classify various ions as three groups. It is also found that the main factors which determine the stability of water structures around the ions are the charges and dimensions of ions.
Chemical Synthesis and Biological Activities of Two Disaccharide Dipeptides Corresponding to the Repeating Units of Bacterial Peptidoglycan
Authors: Kusumoto Shoichi , Yamamoto Koji , Imoto Masahiro , Inage Masaru , Tsujimoto Masachika , Kotani Shozo , Shiba Tetsuo
Published: July 2006

Two disaccharide dipeptides, i.e., O-(N-acetyl-β-d-glucosaminyl)-(1→4)-N-acetylmuramyl-l-alanyl-d-isoglutamine (2) and O-(N-acetyl-β-muramyl-l-alanyl-d-isoglutamine)-(1→4)-N-acetyl-d-glucosamine (3), which correspond to partial structures of cell wall peptidoglycan were synthesized via the same glucosamine disaccharide as a common intermediate. Thus, selective introduction of lactic acid moiety on either one of the sugar moieties of the intermediate gave two disaccharides respectively which contain muramic acid on either reducing or nonreducing side. Coupling of the peptide moiety followed by deprotection afforded 2 and 3. The results of biological tests showed that both 2 and 3 have the same magnitude of immunostimulating activities as those of N-acetylmuramyl-l-alanyl-d-isoglutamine which is the minimum structure required for expression of the activities.
Acid-Dissociation Behavior of para-Hydroxyl Group in the N,N,O-Terdentate Ligand, 4-(4-Methyl-2-pyridylazo)resorcinol, Coordinated to a Transition Metal Ion
Authors: Kudo Yoshihiro , Yoshida Noboru , Fujimoto Masatoshi , Tanaka Katsumi , Toyoshima Isamu
Published: July 2006

The acid-dissociation behavior of 1:1 and 1:2 complexes of transition metals with an N,N,O-terdentate ligand, 4-(4-methyl-2-pyridylazo)resorcinol (4-Me PAR), is spectrophotometrically studied in ethanol at 25 °C. The values of apparent pKa of the p-hydroxyl group of the ligand in the metal complexes are found to be in the order, Pd(II)<Co(III)<Ni(II)<Mn(II). The electronic structures of the p-hydroxyl oxygen atoms in the solid complexes of Mn(II), Ni(II), Pd(II), and Co(III) are examined on the basis of the data of X-ray photoelectron spectroscopy (XPS). The decrease in the electron density on the p-hydroxyl oxygen atom caused by the inductive effect through the azo nitrogen and the benzene ring of the coordination of the ligand to the central metal atom is larger in the Pd(II) and Co(III) complexes compared with that in the Ni(II) and Mn(II) complexes.
The Synthesis, Magnetic, and Spectroscopic Properties of Binuclear Iron(III) Complexes Bridged by Pyrazine, 1,1′-Tetramethylenebis(imidazol), or Bis(pyridine) Compounds Exhibiting a Spin-Equilibrium Behavior
Authors: Ohta Shoichi , Yoshimura Chikako , Matsumoto Naohide , Okawa Hisashi , Ohyoshi Akira
Published: July 2006

Five binuclear iron(III) complexes bridged by pyrazine, 1,1′-tetramethylenebis(imidazol), or bis(pyridine) compounds with the formula of [LFe(Bge)FeL](BPh4)2 have been prepared, and their spin-equilibrium behavior between high-spin(S=5/2) and low-spin(S=1/2) states has been investigated by means of the temperature dependences of the magnetic susceptibilities and the electronic spectra, where Bge denotes pyrazine, 1,1′-tetramethylenebis(imidazol), 4,4′-bipyridine, 4,4′-ethylenebis(pyridine), or 4,4′-vinylenebis(pyridine), L=bis(3-salicylideneaminopropyl)amine, and BPh4−=tetraphenylborate. The pyrazine complex is low-spin, while the bis(imidazole) and the bis(pyridine) complexes snowed a spin-equilibrium between high-spin and low-spin states, accompanied by a striking thermochromism in both the solids and solutions.
Structure Determination of Shinjulactones M and N, New Bitter Principles from Ailanthus altissima SWINGLE
Authors: Niimi Yoshio , Tsuyuki Takahiko , Takahashi Takeyoshi , Matsushita Kazuhiro
Published: July 2006

Two new quassinoids, shinjulactones M and N were isolated from root bark of Ailanthus altissima SWingle. The structures of these compounds were determined to be 11β,20-epoxy-1β,11α,12α,13β,21-pentahydroxypicras-3-ene-2,16-dione and 11β,20-epoxy-1β,2α,11α,12α,15β-pentahydroxypicrasa-3,13(21)-dien-16-one, respectively, by spectral and chemical means.
Photochemical Reaction of 2,3-Dichloro-1,4-naphthoquinone with Enol Silyl Ethers
Authors: Maruyama Kazuhiro , Tai Seiji , Imahori Hiroshi
Published: July 2006

2-Oxoalkylated 1,4-naphthoquinones were obtained in the photochemical reactions of 2,3-dichloro-1,4-naphthoquinone with 2-trimethylsiloxy-1-alkenes. Application of this method afforded a wide variety of functionalized 2-oxoalkylated 1,4-naphthoquinones. The photochemical reactions of 2,3-dichloro-1,4-naphthoquinone with 1-alkyl-2-(trimethylsiloxy)ethylenes gave naphthol derivatives. However, 1,1-dialkyl-2-(trimethylsiloxy)ethylenes gave none of products.
Reactions of α-Polyhalo Ketone Tosylhydrazones with Sulfide Ion and Primary Amines. Cyclization to 1,2,3-Thiadiazoles and 1,2,3-Triazoles
Authors: Sakai Kunikazu , Hida Nobuko , Kondo Kiyosi
Published: July 2006

Trichloroacetaldehyde tosylhydrazone acts as an excellent precursor of diazodithioacetate which is generated by treatment of the hydrazone with sulfide ion. This spontaneously cyclizes it to 5-mercapto-1,2,3-thiadiazole. The precursor also gives a 5-amino-1,2,3-triazole on reaction with an amine. α,α-Dichloro ketone tosylhydrazones similarly cyclize to give 1,2,3-thiadiazoles and 1,2,3-triazoles.
A High-Resolution Solid-State 23Na NMR Study of Sodium Complexes with Solvents, Small Ligand Molecules, and Ionophores. 23Na Chemical Shifts as Means for Identification and Characterization of Ion–Ion, Ion–Solvent, and Ion–Ligand Interactions
Authors: Tabeta Ryoko , Aida Misako , Saitô Hazime
Published: July 2006

We have recorded static and magic angle spinning (MAS) 23Na NMR spectra of a variety of inorganic salts, solvent complexes, and complexes with small ligand molecules and ionophores in the solid state, in order to obtain the 23Na chemical shifts of the ion–ion, ion–solvent, and ion–ligand interactions, respectively. In all cases, MAS resulted in considerable reduction of the linewidths. The observed 23Na chemical shifts were corrected by subtracting the displacements by the quadrupole interaction when the quadrupole coupling constants cannot be ignored. We found that the range of the 23Na chemical shifts found in the solid state is about 60 ppm and the 23Na chemical shift of NaBPh4 appears at the highermost region (−52 ppm). The 23Na NMR chemical shifts of these complexes exhibited their characteristic peak positions, depending on variety of ligand molecules (H2O, ether, or carbonyl) and Na–O interatomic distances but independent of the type of counterion. Finally, an attempt was made to relate the 23Na chemical shifts to the magnitude of electron transfer from the ligand molecules to 3p orbital of Na+ ion, by means of an ab initio molecular orbital method.
Syntheses of Althiomycin Analogs in Relation to Antibacterial Activities
Authors: Inami Kaoru , Shiba Tetsuo
Published: July 2006

Four analogs of an antibiotic althiomycin were synthesized in order to clarify the structure-activity relationships, especially with regard to two asymmetric centers and the aldoxime configuration. The antibiotic activity of de(hydroxymethyl) analog is comparable to that of the original antibiotic for Gram-positive bacteria.
Determination of the Equilibrium and Kinetic Parameters for the Surface-Redox Reaction of Hydroquinone Moiety of Adsorbed Adriamycin by Means of Numerical Simulation of d.c. Voltammogram
Authors: Konse Tomonori , Kano Kenji , Kubota Tanekazu
Published: July 2006

Electrochemical equilibrium and kinetic parameters for a redox reaction caused by the hydroquinone moiety of adriamycin adsorbed on a pyrolytic graphite electrode have been determined by means of a numerical simulation of the quasi-reversible d.c. voltammograms using a theory regarding a two-step one-electron surfaceredox reaction, since the electron-transfer rate constant is so small that the reversible d.c. wave can not be obtained and an analysis by a.c. voltammetry is difficult. The voltammogram was also analyzed from the viewpoint of a one-step two-electron surface-redox reaction mechanism taking into account the interaction parameters between adsorbed molecules. The analyses in terms of both mechanisms mentioned above reveal that the redox system considered here occurs through a two-step process.
Proton Inventory of Carboxypeptidase Y-Catalyzed Reactions
Authors: Kunugi Shigeru , Tanabe Kazuo , Fukuda Mitsuhiro
Published: July 2006

The partial solvent isotope effect of D2O on the carboxypeptidase Y-catalyzed hydrolysis of a peptide (3-(2-furyl)acryloyl-l-phenylalanyl-l-phenylalanine) and an ester (3-(2-furyl)acryloyl-l-phenylalanine ethyl ester) was investigated. The peptide hydrolysis showed a smaller kinetic isotope effect regarding the catalytic rate constant (kcat) and the second-order rate constant (kcat⁄Km). kcat Varied linearly on the heavy-water content, indicating that one proton is essentially transferred during the rate-determining step. On the other hand, an ester hydrolysis showed a larger, nonlinear effect, indicating the possibility of a transfer of two or more protons in the rate-determining step of the ester hydrolysis, possibly the deacylation step.
A Convenient Preparative Method of Nitrile Oxides by the Dehydration of Primary Nitro Compounds with Ethyl Chloroformate or Benzenesulfonyl Chloride in the Presence of Triethylamine
Authors: Shimizu Tomio , Hayashi Yoshiyuki , Shibafuchi Hiroshi , Teramura Kazuhiro
Published: July 2006

Three nitrile oxides (MeOCOC≡N→O, PhC≡N→O, and EtC≡N→O) were effectively generated in situ by dehydration of the corresponding primary nitro compounds (RCH2NO2) with PhSO2Cl or ClCOOEt in the presence of triethylamine. Various cycloadducts were prepared by the reaction of them with dipolarophiles. Some advantages of these methods are described in comparison with other known methods.
Pseudo-Sugars. XVI. Facile Synthesis of Pseudo-α-d and l-Glucopyranoses
Authors: Ogawa Seiichiro , Nakamura Kazufumi , Takagaki Tohei
Published: July 2006

Optically active pseudo-α-glucopyranoses have been synthesized from enantiomeric (1,3,5/2,4)-2,3-diacetoxy-4,5-dibromo-1-cyclohexanecarboxylic acids, obtained by optical resolution of the racemic modification using (+)-and (−)-α-methylbenzylamines.
Preparation of 2-Azido-2-deoxypentose Derivatives
Authors: Hashimoto Hironobu , Araki Koichi , Saito Yoshihiro , Kawa Manabu , Yoshimura Juji
Published: July 2006

2-Azido-2-deoxypentose derivatives having d-xylo and l-arabino configurations were prepared via azidonitration of 1,5-anhydro-2-deoxypent-1-enitols, that is, xylal and arabinal derivatives, respectively. The l-ribo isomer was prepared by substitution of 2-trifluoromethylsulfonyloxy and 2-(1-imidazolylsulfonyloxy) group with azide. The d-xylo isomer was converted into the corresponding d-ribo and d-lyxo isomers.
Reaction of Olefins with Malonic Acid Derivatives in the Presence of Manganese(III) Acetate
Authors: Fujimoto Noriyuki , Nishino Hiroshi , Kurosawa Kazu
Published: July 2006

The reaction of methylmalonic acid with mono- and disubstituted olefins in the presence of manganese(III) acetate yielded 2-carboxy-2-methyl-4-butanolides in moderate to good yields. The reactions of bromomalonic acid and chloromalonic acid with a variety of olefins gave 2-halo-4-butanolides and/or 2-buten-4-olides. The reaction of ethyl hydrogen malonate with olefins in the presence of manganese(III) acetate yielded 2-ethoxycarbonyl-2-buten-4-olides, 2-ethoxycarbonyl-2-ethenyl-4-butanolide, 2,7-dioxaspiro[4.4]nonane-1,6-diones, 2-ethoxycarbonyl-4-butanolide, and ethyl 3-butenoate. These reactions can be accounted for in terms of a free-radical mechanism involving substituted dicarboxymethyl radicals.
Photochemical Addition of Benzyltriethylgermane and Dibenzyldiethylgermane to Olefins
Authors: Kobayashi Masanori , Yoshida Masato , Kobayashi Michio
Published: July 2006

A novel photochemical addition of a germyl radical to the olefinic double bond was discovered when benzyltriethylgermane or dibenzyldiethylgermane was irradiated with a medium-pressure mercury lamp in the presence of olefins.
The Preparation of Polythia[n](1,1′)ruthenocenophanes. Their Platinum Group Metals Complexes and Their X-Ray Crystal Structures
Authors: Akabori Sadatoshi , Sato Sadao , Tokuda Takehiko , Habata Yoichi , Kawazoe Kayoko , Tamura Chihiro , Sato Masaru
Published: July 2006

Polythia[n](1,1′)ruthenocenophanes were prepared by reaction of 1,1′-bis(2-chloroethylthio)ruthenocene with disodium alkanedithiolates in tetrahydrofuran/ethanol. The ruthenocenophanes efficiently formed 1 : 1 complexes with platinum and palladium dichlorides. X-Ray crystallography of complexes of the 1,4,7,10-tetrathia[n](1,1′)ruthenocenophane with PtCl2 and PdCl2 revealed that the Pt (or Pd) atom bonded selectively to the two sulfur atoms at the 4,7-positions among the four sulfur atoms in the bridge of the ligand with a slightly distorted cis square-planar configuration. The conformation of the organic moiety in the 1 : 1 complex is greatly changed from that of the metal-free ligand. Also, the 1 : 1 palladium complex is isomorphous with the 1 : 1 platinum complex.
Reactions of Schiff Bases with Superoxide Ion in Acetonitrile
Authors: Shibata Katsuyoshi , Saito Yoshiyuki , Urano Katsuyoshi , Matsui Masaki
Published: July 2006

The reactions of Schiff bases such as N-benzylideneanilines with superoxide ion in acetonitrile under mild conditions gave the cyanomethyl adducts, 3-arylamino-3-arylpropionitriles, as the main products in relatively good yields. In the case of N-(4-nitrobenzylidene)aniline, the adduct was further oxidized to β-anilino-4-nitrocinnamonitrile. No oxidative products such as amides were obtained except in the reactions of N-(4-chloro- and 4-nitrobenzylidene)aniline.
Equilibrium and Kinetic Studies of the Dimerization of Acridine Orange and Its 10-Alkyl Derivatives
Authors: Murakami Kiyofumi , Mizuguchi Katsumi , Kubota Yukio , Fujisaki Yasuo
Published: July 2006

The thermodynamics and kinetics of the dimerization of Acridine Orange (AO, 3,6-bis(dimethylamino)acridinium chloride) and its 10-alkyl derivatives in 0.1 M NaCl solution have been studied by spectrophotometry and temperature-jump method. Dimerization constants, which were determined spectrophotometrically, become large with an increase in the length of the introduced alkyl chain; this behavior is the same as that in water and a dilute HCl solution. The association and dissociation rate constants determined from the temperature-jump measurements also depend on the length of the alkyl chain. Especially, the rate constants for methyl–AO are unexpectedly small. Both the effect of added salt on the thermodynamic parameters and the kinetic results are discussed in view of the structure of hydration water surrounding dye molecules. 1H NMR data for AO and methyl–AO suggest that the planes of two component molecules in a dimer are parallel to each other. This result is consistent with the spectrophotometric and kinetic data.
Exciplexes in Perfluorohydrocarbon. Charge-Transfer Interaction between Exciplexes and Perfluorohexane
Authors: Kano Koji , Yanagimoto Masaru , Hashimoto Shizunobu
Published: July 2006

The rate constants for photochemical processes of pyrene in perfluorohexane (PFH) and hexane containing N,N-dimethylaniline (DMA) have been determined by analyzing the rise and decay curves of the pyrene–DMA exciplex to study the interaction between electronically polar exciplex and an extremely nonpolar solvent, PFH. In PFH, the dissociation of the exciplex to the original pyrene in the excited singlet state and DMA was decelerated and the radiationless deactivation of the exciplex to the ground states was accelerated. In the case of the naphthalene–triethylamine exciplex system, the radiationless deactivation of the exciplex was also much faster in PFH than in hexane. These results suggest charge-transfer interactions between the polar exciplexes and PFH. The negative charges of the exciplexes may transfer to the strongly electronegative fluorine atom(s) of PFH. The deceleration of the back reaction and the acceleration of the radiationless deactivation seem to lead the efficient fluorescence quenching of pyrene and naphthalene by amines in PFH.
Magnetic Properties of Dimeric Copper(II) 2,2-Dimethylpropanoate Complexes
Authors: Muto Yoneichiro , Hirashima Nobuchika , Tokii Tadashi , Kato Michinobu , Suzuki Ikuo
Published: July 2006

Dimeric copper(II) 2,2-dimethylpropanoate complexes, [Cu(Me3CCOO)2·L]2, where L is pyridine, acridine, quinaldine, 2-picoline, 4-picoline, and 2,6-lutidine, have been prepared. Magnetic data show that the singlet–triplet separation (−2J) ranges from 319 to 397 cm−1. Strong antiferromagnetic interaction observed for the acridine adduct (−2J=397 cm−1) is discussed on the basis of weak Cu–N(acridine) bond. The magnetic behavior of the non-adduct compound [Cu(Me3CCOO)2]2 (−2J=403 cm−1) is explained with respect to its non-polymeric structure.
Reactions of Alkyl Isothiocyanates with Dianions of Cyclic Thioureas
Authors: Matsumura Noboru , Tomura Masaaki , Mando Ritsuo , Tsuchiya Yuko , Yoneda Shigeo
Published: July 2006

The reactions of methyl (or ethyl) isothiocyanate with dianions (4, 5, and 6), which are readily derived from available cyclic thioureas (1, 2, and 3) with butyllithium, gave ring fused 1,3-disubstituted 1,3,5-triazine-2,4(1H,3H)-dithiones (7) and/or thiocarbamoyl derivative (8) as major products.
Cobalt(III)-Peroxo Complexes Containing 1,2-Bis(dimethylphosphino)ethane (dmpe) or 1,3-Bis(dimethylphosphino)propane (dmpp). Molecular Structures of [Co(O2)(dmpe)2]B(C6H5)4 and [Co(O2)(dmpp)2]BF4·H2O
Authors: Ohishi Tomoji , Kashiwabara Kazuo , Fujita Junnosuke , Ohba Shigeru , Ishii Toshio , Saito Yoshihiko
Published: July 2006

Monomeric (yellow) and dimeric (red) cobalt(III)–dioxygen complexes containing 1,2-bis(dimethylphosphino)ethane (dmpe) have been prepared from [Co(dmpe)2]+ and [Co(dmpe)2]2+, respectively, by air oxidation. The 1,3-bis(dimethylphosphino)propane (dmpp) complex afforded only the monomeric dioxygen complex by either preparative method. The crystal structures of [Co(O2)(dmpe)2]B(C6H5)4 (1) and [Co(O2)(dmpp)2]BF4·H2O (2) have been determined by X-ray analysis. Crystal data for 1; monoclinic, P21⁄a, a=18.011(12), b=18.761(10), c=11.455(6) Å, β=107.78(4)°, V=3686(4) Å3, Z=4, and R=0.064. Crystal data for 2; orthorhombic, Pbcn, a=14.540(5), b=13.123(4), c=13.138(2) Å, V=2507(1) Å3, Z=4, and R=0.076. The complex ions in both 1 and 2 have a trigonal-bipyramidal coordination geometry when the O2 group bonded to the Co atom in the side-on form at a coordination site of the trigonal plane is assumed to be a unidentate ligand. Bond lengths. Co–O (1.858(7)–1.881(4) Å) and O–O (1.414(12) and 1.425(6) Å), and O–O stretching frequencies (877 and 862 cm−1) indicate that both 1 and 2 are the peroxo complexes. The monomeric dioxygen complexes react immediately with SO2 and with concd HCl to afford [Co(SO4)(dmpe or dmpp)2]+ and cis-[CoCl2(dmpe or dmpp)2]+, respectively. The red dimeric trans-[(dmso)(dmpe)2Co(μ-O2)Co(dmpe)2(dmso)](BF4)4 (dmso=dimethyl sulfoxide) complex was isolated and characterized.
Convenient Synthesis of 3-Aminocoumarin Derivatives by the Condensation of 1,4-Diacetyl- or 3-Substituent-2,5-piperazinediones with Various Salicylaldehyde Derivatives
Authors: Shin Chung-gi , Nakajima Yoshiharu , Haga Toshiya , Sato Yoshiaki
Published: July 2006

The condensation of 1,4-diacetyl- or 3-substituted 2,5-piperazinediones (PDO) with various salicylaldehyde derivatives in the presence of a base, such as potassium t-butoxide or triethylamine, was found to give two extremely different kinds of products: 1-acetyl-3-arylmethylene-PDO and 3-(acylamino)coumarin derivatives. The former, which has a (Z)-geometric structure, was readily converted to the latter by irradiation. Furthermore, the conversion mechanism and the structural confirmation are discussed.
Paramagnetic Cobalt(III) Complexes with Organic Ligands. IX. The Preparation and Properties of Paramagnetic Tetraammine(5-nitrosalicylideneaminato)cobalt(III) Complexes
Authors: Yamamoto Yoshihisa , Toyota Eiko
Published: July 2006

The title paramagnetic cobalt(III) complexes, (Remark: Graphics omitted.),(X3: Cl2·NO3, (NO3)3), both green color, have been isolated and characterized by analytical, spectroscopic and magnetic methods. The effective magnetic moments are 1.7 BM, suggesting an unpaired spin. The 1H NMR spectra indicate that the unpaired spin on the complexes is localized over the π-orbitals of the chelated ligand. In the XPS, the high binding energy area at 286–289 eV of the C ls peak of both the complexe is larger than that for the corresponding diamagnetic cobalt(III) complex. The cobalt 2p peaks do not have satellites in the same manner as the usual diamagnetic cobalt(III) complexes. It can be concluded that an unpaired spin on complexes is not located on the cobalt atom, but is located over the π-orbitals of the chelated ligand of complexes.
1H NMR Studies on the Reorientational Motions of Cations in Four Solid Phases of Methylammonium Iodide and the Self-Diffusion of Ions in Its Highest-Temperature Solid Phase
Authors: Ishida Hiroyuki , Ikeda Ryuichi , Nakamura Daiyu
Published: July 2006

Four solid phases of CH3NH3I named as α′, β′, δ, and ε were studied by the temperature dependence of 1H spin-lattice relaxation time T1 and 1H spin–spin relaxation time T2 (for ε) at several NMR frequencies, and of 1H NMR second moment. Phase transitions were studied by means of differential thermal analysis and 1H T1. The X-ray powder patterns of the highest-temperature ε phase taken at ca. 440 K revealed that the crystal forms a CsCl-type cubic lattice. The measurements of differential scanning calorimetry gave unusually small entropy of melting indicating that the cations of the ε phase are in a state having the most part of their motional freedom. From 1H NMR T1 experiments, it was found that the transformation of the room-temperature α′ phase to the low-temperature stable β′ phase needed longer time than three months at Dry Ice temperature for samples carefully purified and dried for a long time under vacuum whereas it was completed within two weeks for roughly dried samples. The NMR results indicated that the cations are bound tightly in the β′ phase whereas they are fairly free to reorient in the low-temperature substable δ phase. In the α′ phase, the cations perform C3 reorientations very rapidly about their C–N bond axis. The cations of the ε phase undergo overall rotation as well as self-diffusion which was confirmed by electrical conductivity measurements. The mechanism of the self-diffusion of the cations is discussed.
Glycinoeclepins, Natural Hatching Stimuli for the Soybean Cyst Nematode, Heterodera Glycines. II. Structural Elucidation
Authors: Masamune Tadashi , Fukuzawa Akio , Furusaki Akio , Ikura Mitsuhiko , Matsue Hideki , Kaneko Tatsuya , Abiko Atsushi , Sakamoto Noriyasu , Tanimoto Norihiko , Murai Akio
Published: July 2006

The structures of three new compounds, glycinoeclepins A, B, and C, isolated from the hatch-stimulating extracts of kidney beans for the soybean cyst nematode, have been determined. The structures were resolved by using spectroscopic methods, especially by the difference NOE techniques, and confirmed by the X-ray diffraction analysis. These structures are characterized by (1) migration of two methyl groups in the C and D rings, (2) oxidative cleavage of the B ring with loss of one carbon atom and (3) presence of the 7-oxabicyclo[2.2.1]heptane system in the A ring, compared with those of cycloartanes, and are regarded as pentanor- (GEA) or nortriterpenes (GEB and GEC).
Quinoxaline Derivatives. XII. The Reactions of Quinoxaline 1,4-Dioxides with Acetic Anhydride
Authors: Ahmed Yusuf , Qureshi M Ikram , Habib M Saleem , Farooqi M Amir
Published: July 2006

Quinoxaline 1,4-dioxide (XIIIa) with acetic anhydride gave 1-acetoxy-2(1H)-quinoxalinone (XIVa) which was prone to facile hydrolysis to yield 1-hydroxy-2(1H)-quinoxalinone (XVa). Both XIVa and XVa were isolated from the reaction mixture. On prolonged heating with acetic anhydride, XIIIa, XIVa, and XVa were converted slowly to the same end product, 2,3(1H,4H)-quinoxalinedione (XXa). 6-Ethoxy- (XIIIb), 6-methoxy- (XIIIc), and 6-methylquinoxaline 1,4-dioxide (XIIId) behaved similarly, except that the attack of the reagent took place exclusively on N-oxide para to the electron-donating substituents, and none of the other expected isomeric compounds XVIIb–d were isolated. Whereas 6-chloroquinoxaline 1,4-dioxide (XIIIe) bearing an electron-attracting chloro substituent on the benzene ring gave exclusively the other isomers XVIIe, XVIIIe, and XXe. A mechanism for this novel rearrangement is proposed and discussed.
Coordination-Site Exchange of Azaheterocyclic Ligands in Five-Coordinate Palladium(II) Complexes. Bis(4,7-dimethyl-1,10-phenanthroline)(triphenylphosphine)palladium(II) Tetrafluoroborate and the 4,7-Diphenyl Derivative
Authors: Yamazaki Shinsaku
Published: July 2006

Variable-Temperature 1H NMR suggests that the fluxional motion of a potentially five-coordinate complex [Pd(PPh3)(4,7-R2-phen)2][BF4]2 (R=Me, Ph) is frozen at lower temperatures, where the complex is in a rigid configuration (an unusual trigonal bipyramid). The fluxional motion is explained by two synchronous rearrangement systems, and an activation parameter, ΔG*, for the site exchange is given.
The Crystal and Molecular Structure of Bis(dibenzylamine)bis(thiocyanato)cadmium(II), Cd(SCN)2{(C6H5CH2)2NH}2
Authors: Taniguchi Masahiro , Ouchi Akira
Published: July 2006

The crystal and molecular structure of the title complex was determined by means of a single-crystal X-ray diffraction technique. A crystal of CdC30H30N4S2, F.W.=623.13, is triclinic, with a space group P\bar1, a=11.284(2), b=11.404(2), c=5.974(1) Å, α=93.31(2), β=98.37(1), γ=71.84(1)°, U=722.6(2) Å3, Z=1, Dm=1.42(3) Dx=1.43 Mg m−3, and μ(Mo Kα)=9.17 cm−1. The cadmium(II) atom is hexa-coordinated, being ligated with two thiocyanato(SCN)sulfur atoms as well as two SCN and two dibenzylamine nitrogen atoms, where the respective pairs of the same kinds of atoms are all in a trans-configuration. All cadmium(II) atoms are lined along the c-axis and the side-by-side metal atoms are doubly bridged by SCN ions.
Molecular-Weight Dependence of the Polymer Adsorption at Solid-Liquid Interfaces as Studied by ESR Spectroscopy
Authors: Sakai Harutoshi , Imamura Yoshio
Published: July 2006

The conformation of poly(methyl methacrylate) adsorbed from dilute solution on nonporous silica was investigated by ESR method using three-component spectrum analysis. The fraction of the polymer segments in train, short loop, and long loop or tail, as well as the rotational correlation time for the segments were examined with regard to molecular weight (M=103–3×106), the degree of adsorption, and the particle size of silica. In CCl4, the saturation adsorption, As, increased from 6 to 16×10−8 g cm−2, the fraction of polymer segments in train, p, decreased from 0.9 to 0.4, and the segment mobility reduced with the increase in molecular weight, respectively. Remarkable changes in As and p were found in a range of molecular weight of 5×104. In benzene, the values of As and p were less dependent on molecular weight than the cases of adsorption in CCl4. Marked effects of intrachain interactions on the conformation were revealed for the adsorption of coiled polymers with high molecular weight from CCl4 solution at low degrees of adsorption, where the loop formation was observed for polymers of M>104. The intrachain force was attributed to overlapping among the segments. The difference in the adsorption behavior between the cases in CCl4 and benzene was interpreted by the difference in the degree of deformation of polymer molecules upon adsorption.
Extraction and Transport of Ions in a Liquid Membrane Containing Crown Ether
Authors: Sakim Maria , Hayashita Takashi , Yamabe Takeo , Igawa Manabu
Published: July 2006

The ion-transport mechanism through a liquid membrane containing dibenzo-18-crown-6 as a carrier was investigated by measuring the salt flux, the distribution coefficient to the membrane phase, and the membrane potential. The salt flux increased to a great extent with the activity of the source phase solution, but the effect of the activity on the distribution coefficient varied with the membrane solvent. The mobility ratio of cations to anions increased with an increase in the hydrophobicity of the membrane solvent. Although the selectivity of the cation transport is controlled mainly by the size of the crown ring, the hydrophobicity of the cation also influenced the salt flux and the flux of a slightly hydrated large cation, such as cesium ion, was high. The hydration degree of anions influenced the salt flux considerably since the stability constants of the crown ether complexes accompanied by a hydrophobic anions were very high. The salt flux correlated well with the lyotropic number of anions.