bluuebunny/crossref_metadata_2025 huggingface dataset:
Coordination of Water Hydrogen-Bonded to Pyridine Derivatives to the (1R,4S,8R,11S)-1,4,8,11-Tetramethyl-1,4,8,11-tetraazacyclotetradecanenickel(II) Cation in Nitrobenzene
Authors: Nishimoto Jun , Hironaka Akira , Iwamoto Etsuro , Kumamaru Takahiro
Published: August 2006

The axial coordination of pyridine, 2-methylpyridine, 4-methylpyridine and water (W) hydrogen-bonded to each donor solvent (S) to the (1R,4S,8R,11S)-1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecanenickel(II) cation ([Ni(tmc)]2+) in nitrobenzene has been investigated spectrophotometrically. Pyridine and its derivatives are hardly coordinated to [Ni(tmc)]2+ owing to steric hindrance, but the water which is hydrogen-bonded to the donor solvent as a 1 : 1 complex (WS) can be easily coordinated to form the five coordinated [Ni(tmc)(WS)]2+ cation with a coordination constant (KMWS in dm3 mol−1) of 6.5 for pyridine, 5.7 for 2-methylpyridine, and 11.5 for 4-methylpyridine. The smaller KMWS value for 2-methylpyridine is due to steric hindrance. It was found that the residual hydrogen atom of the coordinated water in WS can be hydrogen-bonded to further species such as S and WS to form additional kinds of five-coordinated complexes, [Ni(tmc)(WS–S)]2+ and [Ni(tmc)(WS–WS)]2+. Coordination of the doubly hydrogen-bonded water (WS–S) which is induced as a result is stronger for 4-methylpyridine than for pyridine. This reflects the substituent effect of 4-methyl group on the basicity. The basicity of pyridine and its derivatives has been discussed in connection with the electrostatic/charge-transfer balance for hydrogen-bonding, compared with dimethyl sulfoxide.
Crystal Structures of [Co(acac)2{(CH3)2XCH2CH2NH2}]ClO4 (X = N, P, As; acac = 2,4-Pentanedionate Ion)
Authors: Kita Masakazu , Nemoto Kazuhiro , Kashiwabara Kazuo , Fujita Junnosuke , Goto Masafumi , Miyamoto Toshiro , Ohba Shigeru
Published: August 2006

The structures of [Co(acac)2{(CH3)2XCH2CH2NH2}]ClO4 (acac = 2,4–pentanedionate ion, X = N (complex 1), P (complex 2), and As (complex 3)) with a series of group 15 donor atoms were determined by the single-crystal X-ray diffraction method. Crystal data and final R values are: for 1, orthorhombic, Pba2, a = 13.192(2), b = 25.504(5), c = 11.840(2) Å, V = 3984(1) Å3, Dm = 1.47(2), Dx = 1.48 g cm−3 and Z = 8, R = 0.050 for 2684 reflections. For 2, monoclinic, P21/c, a = 13.953(6), b = 25.061(10), c = 12.079(7) Å, β = 92.29(6)°, V = 4220(2) Å3, Dm = 1.45(3), Dx = 1.45 g cm−3, Z = 8, R = 0.084 for 5801 reflections. For 3, monoclinic, C2/c, a = 28.125(9), b = 13.303(1), c = 12.647(4) Å, β = 115.41(4)°, V = 4274(2) Å3, Dm = 1.50(3), Dx = 1.54 g cm−3, Z = 8, R = 0.051 for 3698 reflections. All the complex ions have a similar structure, forming a distorted octahedron with 4O, N, and X donor atoms. The Co–X bond lengths are av. 2.026(8) Å for 1, av. 2.192(3) Å for 2, and 2.302(1) Å for 3. The Co–O bond lengths trans to X are av. 1.886(6) Å for 1, av. 1.950(5) Å for 2, and 1.928(3) Å for 3, which are longer by 0.002(6), 0.065(6) and 0.037(4) Å, respectively, than the average lengths of other three Co–O bonds (1: av. 1.884(6), 2: av. 1.885(6), 3: 1.891(4) Å).
Oxidation of Alcohols to Aldehydes and Ketones over Hydrous Zirconium(IV) Oxide Modified by Trimethylsilyl Chloride
Authors: Kuno Hideyuki , Shibagaki Makoto , Takahashi Kyoko , Matsushita Hajime
Published: August 2006

A modified catalyst was prepared by the reaction of trimethylsilyl chloride and hydrous zirconium(IV) oxide. It was then applied to the oxidation of alcohols by using carbonyl compounds as hydrogen acceptors. In the case of cycloalkanols, the oxidation proceeded efficiently to give the corresponding ketones. Further, primary aliphatic alcohols were converted to the corresponding aldehydes in high yields in a batch reaction system. In addition, it was investigated that the oxidation was influenced by a variety of solvents and hydrogen acceptors.
Measurement and Linear Correlation of the Solvent Polarity Parameters of Supercritical Carbon Dioxide and Its Cosolvent Systems
Authors: Ikushima Yutaka , Saito Norio , Arai Masahiko
Published: August 2006

The solvent polarity parameters, including the dipolarity/polarizability π* parameter, hydrogen-bond donor acidity α parameter, and hydrogen-bond acceptor basicity β parameter, were measured for supercritical carbon dioxide and cosolvent systems with ethanol, 2,2,2-trifluoroethanol, and dimethyl sulfoxide at pressures of 9.81—27.95 MPa and 318 K. A linear correlation was examined for relating those parameters with each other.
Redox Potentials of Cobalt (III/II) Complexes with Sulfonated Heterocyclic Azo Compounds
Authors: Yuchi Akio , Matsui Katsuhito , Ishizuki Tomosuke , Wada Hiroko
Published: August 2006

Cyclic voltammograms of the cobalt(III) complexes with sulfonated azo compounds indicated one quasi-reversible electrode process at the Pt or Au electrode at −0.3—0 V vs. SCE in aqueous solutions, which was assigned to a metal-centered redox reaction. The formal potentials are linearly correlated with the logarithmic protonation constants of the ligands.
Syntheses and Properties of New (Alkyl)dioxo[tris(3,5-dimethyl-1-pyrazolyl)hydroborato]molybdenum(VI) Complexes
Authors: Onishi Masayoshi , Ikemoto Kazuto , Hiraki Katsuma , Koga Ruri
Published: August 2006

New (alkyl)dioxo[tris(3,5-dimethyl-1-pyrazolyl)hydroborato]molybdenum(VI) complexes, where “alkyl” refers to methyl and trimethylsilylmethyl groups, were prepared as white microcrystals, and were characterized by NMR and IR spectroscopic techniques.
Mechanism for Isomerization of cis-Stilbene via Its Radical Cation as Investigated by Pulse Radiolysis. A Possible Role of a Dimeric Radical Cation as an Intermediate
Authors: Kuriyama Yasunao , Sakuragi Hirochika , Tokumaru Katsumi , Yoshida Yoichi , Tagawa Seiichi
Published: August 2006

Pulse radiolysis of cis-stilbene was carried out and transient absorption spectra were measured in varying concentrations in dichloromethane under air at room temperature. Concentration dependence of the spectral change indicates that cis-stilbene radical cations isomerize to trans-stilbene radical cations through interaction with a neutral cis-stilbene molecule, probably by way of a σ-type dimeric radical cation.
The Pictet-Spengler Reaction on L-Histidine. Preparation of Conformationally Restricted (+)-Pilocarpine Analogs
Authors: Sánchez-Sánchez M del Mar , Tel-Alberdi L M , Rioseras M Jesus , Rico-Ferreira M del Rosario , Bermejo-González F
Published: August 2006

The total regioselective synthesis of the rigid (+)-pilocarpine analogs 4—6 starting from L-histidine is described. The Pictet-Spengler condensation is used to prepare the tetrahydroimidazopyridine moiety present in the structure of these tricyclic derivatives.
Interaction of Methyl Orange with Submicellar Cationic Surfactants
Authors: Dutta Robin K , Bhat Subray N
Published: August 2006

The interaction of aqueous Methyl Orange (MO), an azo dye, with alkyltrimethylammonium and N-hexadecylpyridinium halide surfactants in submicellar concentration ranges has been investigated. The interaction gives rise to a new absorption band of MO with a maximum at ca. 370 nm, and the appearance of the new band has been attributed to change in the chromophore microenvironment in water structure enforced closely packed ion pairs of the dye with submicellar cationic surfactant. The strength of the interaction depends on the alkyl chain length of the surfactant, the surfactant head group and the counter ions.
Semiconductor Photocatalysis: Reaction Mechanisms for the Photoreductive cis–trans Isomerization of Electron-Deficient Alkenes Catalyzed by CdS Powder
Authors: Shiragami Tsutomu , Fukami Shinako , Pac Chyongjin , Wada Yuji , Yanagida Shozo
Published: August 2006

Highly pure commercially available CdS powder (99.999%) catalyzes the effective cis–trans photoisomerization of electron-deficient alkenes under visible light irradiation using triethylamine (TEA) as an electron donor, accompanying the formation of the dihydro compound as a two-electron reduction product. The photoisomerization does not occur at all in the absence of TEA. Donor effect, solvent effect, deuterium incorporation experiments for photocatalysis, and MOPAC molecular orbital calculation (MNDO/PM3) of the intermediary radical anions from the alkenes were investigated in order to elucidate the mechanism of this photoisomerization. These results reveal that the CdS-catalyzed cis–trans photoisomerization should proceed through two pathways involving the photoreduction of alkenes: one through the back electron transfer from the radical anion of the alkene (alkene−•) towards the radical cation of TEA (TEA+•), both formed by photoexcited conduction band electrons and holes of CdS, respectively. The other is the reoxidation of a radical intermediate (alkyl•), formed by protonation of alkene−•, by TEA+•.
Adsorbed Oxygen Species Formed by the Decomposition of N2O on Li/MgO Catalysts
Authors: Nakamura Masato , Yanagibashi Hiroshi , Mitsuhashi Hiroyuki , Takezawa Nobutsune
Published: August 2006

A considerable amount of adsorbed oxygen species were produced by the decomposition of N2O on Li/MgO. The amount of the oxygen species greatly increases by Li(I)-doping on MgO. Over 0.7 wt% Li/MgO, the amount of the oxygen species formed was 10.67 μmol m−2. The temperature-programmed desorption of the oxygen species revealed that two types of adsorbed oxygen species were present on Li/MgO; one (α-oxygen species) desorbed in proportion to the second order in the amount of the adsorbed species with an activation energy of 141 kJ mol−1, giving a peak (α-oxygen peak) at 673—693 K; the other (β-oxygen species) desorbed in proportion to the first order in the amount of the adsorbed species with an activation energy of 219 kJ mol−1, giving a peak (β-oxygen peak) at 753—768 K. A weak α-oxygen peak occurred on MgO and no β-oxygen peak was discerned. On Li/MgO, a β-oxygen peak appeared along with an α-oxygen peak. At higher Li-loadings the β-oxygen peak was more intense than the α-oxygen peak. The sites for these oxygen species were suggested to be derived by the addition of Li(I) on MgO. It was suggested that the α-oxygen species were present at the surface sites on higher index faces of MgO, whereas the β-oxygen species were present at oxygen vacancies in the vicinity of Li(I) substituting for Mg(II). The hydrolysis of these adsorbed oxygen species yielded an appreciable amount of H2O2, suggesting that these species were primarily present as surface peroxide on MgO and Li/MgO.
Influence of Surface Treatment of the p-GaP Photocathode on the Photoelectrochemical Reduction of Carbon Dioxide
Authors: Ikeda Shoichiro , Yamamoto Akio , Noda Hidetomo , Maeda Masunobu , Ito Kaname
Published: August 2006

Effects of the surface treatments of p-GaP electrodes with various etchants on the photoelectroreduction of CO2 were investigated in 0.1 mol dm−3 KHCO3 aqueous solution. The catalytic activities for CO2 photoelectroreduction of p-GaP electrodes depended on the etchants and also their crystallographic orientations, (100) or (111) faces. The reduction products were only HCOO− and CO from CO2, and H2 as a by-product. Aqua regia was prefer to produce HCOO− on both faces. Conc. HCl was effective for HCOO− formation on the (111) face. Although the alkaline potassium hexacyanoferrate(III) solution was effective for reducing the overpotential and increase the photocurrent, the main product was H2. Conc. HNO3 was not effective.
Molecular Dynamics Simulation of Aqueous MNO3 (M = Li, Na, K, Rb, and Cs) Solutions
Authors: Kataoka Yosuke
Published: August 2006

To understand the anisotropy, cation dependence, and concentration dependence of the orientational relaxation time of the nitrate ion, the structure and molecular motion were studied by molecular dynamics simulation of MNO3 (M = Li, Na, K, Rb, and Cs) solutions. The interaction parameters determined for the molten salt were used between the ions. The Carravetta–Clementi potential was assumed for the water–water pair. An empirical combination rule was adopted in the water-ion interactions. Simulations were done at several volumes corresponding to the normal density and low pressures. The temperature was 300 K and the concentrations was 1 or 2 mol kg−1. The distribution of water molecule is almost isotropic around the nitrate ion. No water molecules are found which move in strong correlation with the rotation of the nitrate ion. The calculated orientational relaxation time of the nitrate ion is in agreement with the experimental results qualitatively with respect to its anisotropy, cation dependence, and concentration dependence. These were analyzed by the potential energy of the species around the nitrate ion. The anisotropy of the relaxation time was due to the anisotropic charge distribution in the nitrate ion, as demonstrated by several models.
Liquid Phase Reaction of Acetaldehyde over Various ZSM-5 Zeolites
Authors: Mori Hidemitsu , Yamazaki Tatsuya , Ozawa Sentaro , Ogino Yoshisada
Published: August 2006

Acetaldehyde reacted over various ion-exchanged ZSM-5 zeolites at 15 ± 0.5 °C under a nitrogen pressure of 1 × 105 Pa. The main products of the reaction were 2α,4α,6α-trimethyl-1,3,5-trioxane (cis-paraldehyde) and its isomer, 2α,4α,6β-trimethyl-1,3,5-trioxane (trans-paraldehyde). Several rare earth ZSM-5 (REZSM-5) and M/HZSM-5 (partially proton exchanged ZSM-5) catalysts exhibited high activities for trans-paraldehyde formation. The reaction appeared to proceed by the following scheme: cis-paraldehyde ← acetaldehyde → trans-paraldehyde. A comparison of the catalytic activity with the IR intensity of acidic OH groups over the catalyst suggested that the active site for cis-paraldehyde formation was the Brönsted acidic site, while the active site for trans-paraldehyde formation was a Brönsted acid site in the neighborhood of an Mn+ site in the ZSM-5 zeolite pore.
Photochemistry of Diphenyl Sulfide/Halogen and Mesitylene/Halogen Complexes in Liquid Halocarbons
Authors: Sumiyoshi Takashi , Kawasaki Masahiro , Katayama Meiseki
Published: August 2006

The photochemical reactions of the diphenyl sulfide/X (X = Cl, Br) and mesitylene/X complexes have been studied by the combined pulse radiolysis–laser flash photolysis method. While no photochemistry is observed from the excited state of diphenyl sulfide/Cl complexes in CCl4, permanent photobleaching induced by intermolecular hydrogen abstraction is observed in 1,2-dichloroethane (Φ = 0.05) and in CCl4 which contains an additive such as dichloromethane, cyclohexane, and 2-methyl-2-propanol. The excited state of mesitylene/Cl complexes undergoes solvent independent intramolecular hydrogen abstraction with a quantum yield of 0.10. No photochemistry is observed from the excited states of diphenyl sulfide/Br and mesitylene/Br complexes in CBrCl3 with and without containing cyclohexane. The difference in the bond dissociation energy of H–Cl, H–Br, and C–H explains the dependence of the photochemical reaction modes on both solvents and halogens.
Construction of Defect-Diminished Lithium 10,12-Heptacosadiynoate Monolayer by Means of Crystallization on the Water Surface
Authors: Kuriyama Keisuke , Kajiyama Tisato
Published: August 2006

The melting temperature, Tm of lithium 10,12-heptacosadiynoate monolayer on the water surface was evaluated by a combination of two kinds of measurements, the subphase temperature, Tsp dependence of modulus of the monolayer based on a π–A isotherm and also, the Tsp dependence of the electron diffraction, ED patterns of the monolayer. Tm of the monolayer was evaluated to be 300 K from the results of both an apparent decrease in the Tsp vs. modulus curve and the change of the ED pattern from a crystalline triclinic spot to an amorphous halo. The aggregation structure of the monolayer during a compressing process at Tsp below and above Tm was investigated on the basis of the bright field electron micrograph and the ED pattern. The monolayer on the water surface was classified into a crystalline monolayer and an amorphous one depending on the Tsp below and above Tm of the monolayer, respectively. However, the formation of the crystalline and amorphous monolayers is irrespective of the surface pressure. Furthermore, the defect-diminished crystallized monolayer was prepared by cooling the amorphous monolayer down to a temperature range below Tm.
Spectrophotometric Determination of Palladium(II) Using 4-(Dimethylamino)benzaldehyde Thiosemicarbazone
Authors: Shetty A Nityananda , Gadag Rudrayya V
Published: August 2006

A simple, rapid, and selective spectrophotometric method is proposed for the determination of palladium(II), using 4-(dimethylamino)benzaldehyde thiosemicarbazone (DMABT) as a spectrophotometric reagent. The reagent forms a 1 : 2 complex (Pd : Reagent) with Pd(II) in the pH range 2.2—3.6. The complex is soluble in aqueous solution containing 20% acetone and 30% ethanol by volume. Beer’s law is valid upto 2.3 ppm of palladium. The molar absorptivity is 4.59 × 104 dm3 mol−1 cm−1 and Sandell’s sensitivity 2.33 × 10−3 μg cm−2. The method tolerates large number of cations and anions.
Kjeldahl Digestion Method Formulated by a Criterion Related to the Oxidation Number of Nitrogen
Authors: Shirai Michiko , Kawashima Takeshi
Published: August 2006

A comprehensive Kjeldahl digestion method was formulated based on the criteria that 1) compounds having only nitrogens of oxidation number −III are digested by using H2SO4 with increased K2SO4 without the presence of any other oxidizing agent, and that 2) alternative compounds having nitrogens of oxidation number greater than −III are digested by using H2SO4 with K2SO4 and the reducing agent Zn. This formulation resulted in a satisfactory nitrogen determination of almost all types of organic nitrogen compounds, including those compounds for which it is known to be difficult to analyze using the conventional Kjeldahl method, for example pyridines, pyrazolones, 1,2-diazines, and 1,2,3-triazoles.
Synergic Extraction of Rare Earths(III) with 4,4,4-Trifluoro-1-(2-thienyl)-1,3-butanedione and Nitrogen-Involving Polydentate Ligands as Diethylenetriamine and Triethylenetetramine
Authors: Satake Saeko , Tsukahara Satoshi , Suzuki Nobuo
Published: August 2006

The synergic extraction of rare earths(III), i.e. La, Sm, Tb, and Lu, using 4,4,4-trifluoro-1-(2-thienyl)-1,3-butanedione (Htta) and a nitrogen-involving neutral polydentate ligand, such as diethylenetriamine (dien) or triethylenetetramine (trien), was studied between benzene and aqueous phases. The synergic enhancement of this extraction system was attributed to the formation of an adduct, RE(tta)3dien or RE(tta)3trien. The adduct formation constants (βS,1) were determined. Although βS,1 decreases with the atomic number of RE(III), the detailed tendency of βS,1 depends on the number of nitrogen atoms of the polydentate ligands.
Solvent Extraction of Alkaline Earth Ions with Benzoyltrifluoroacetone into Carbon Tetrachloride in the Absence and Presence of Tetrabutylammonium Ion or Trioctylphosphine Oxide
Authors: Sekine Tatsuya , Takagi Kunihiro , Nguyen Thi Kim Dung
Published: August 2006

The solvent extraction of Mg2+, Ca2+, Sr2+, and Ba2+ (M2+) in aqueous 0.1 mol dm−3 sodium nitrate solutions with benzoyltrifluoroacetone (Hbfa) in carbon tetrachloride was studied in both the absence and presence of tetrabutylammonium ion (tba+) or trioctylphosphine oxide (TOPO). It was found that not only the M(bfa)2 species, but also the tba+M(bfa)3− or the M(bfa)2(TOPO)n species (n is 1 to 3), were extracted by the addition of tba+ or TOPO, and that the extraction was very much enhanced. The equilibria for the extractions were treated as the over-all equilibrium of (i) extraction of the M(bfa)2 chelate and (ii) the association of the ion-pair of the reagents, tba+bfa−, or the TOPO molecules with the chelate in the organic phase. The separation of these four metal ions was improved by the addition of tba+. This was due to the fact that the chelates of smaller M2+ associated with the tba+bfa− better than those of larger M2+ in the organic phase.
Solvent Extraction of Lanthanum(III), Europium(III), and Lutetium(III) with 5,7-Dichloro-8-quinolinol into Chloroform in the Absence and Presence of Tetrabutylammonium Ions or Trioctylphosphine Oxide
Authors: Noro Junji , Sekine Tatsuya
Published: August 2006

The solvent extractions of lanthanum(III), europium(III), and lutetium(III) (M3+) in 0.1 mol dm−3 sodium nitrate solutions with 5,7-dichloro-8-quinolinol(HA) into chloroform were studied in both the absence and presence of tetrabutylammonium ions (tba+) or trioctylphosphine oxide (TOPO). In the absence of tba+ or TOPO, the extracted species were the MA3 and MA3HA (self-adduct), though MA4−tba+ was found when tba+ was added; MA3TOPO and MA3(TOPO)2 were found when TOPO was added in addition to the above mentioned two species. The anionic complex or TOPO adducts greatly enhanced the extraction. The data were statistically analyzed and the equilibrium constants for the extraction of these species, as well as the constants for the association of the HA, the A−tba+, or the TOPO on the MA3 in the organic phase, were determined. The extraction of the MA3 is better in the order LaA3 < EuA3 < LuA3. Although the values of the association constant of the HA or the TOPO on the MA3 are rather similar for the three metal chelates, the constants for A−tba+ are larger in the same order as mentioned above. Thus, the separation of these three metal ions by solvent extraction with this chelating extractant is not much affected by the addition of TOPO, but is greatly improved by the addition of tba+.
Characterization of Calcium-Deficient Hydroxyapatite after a Catalytic Reaction with Trichloroethylene Vapor
Authors: Nishikawa Harumitsu , Ikeda Shigero , Monma Hideki
Published: August 2006

Calcium-deficient hydroxyapatite (DAp) was characterized both before and after an oxidative catalytic reaction with trichloroethylene (TCE) vapor at 450 °C. Most of the Cl in the TCE which decomposed by the reaction was captured as Cl− in DAp. This result supports the assumption reported in a previous paper. On the basis of infrared spectroscopic and X-ray photoelectron spectroscopic results, the captured Cl species was assumed to replace OH− in DAp and to form chloroapatite.
Preparation and Structures of K3[VIII(ox)2(μ-SO4)] and K5[VIII(ox)2(SO4)2]
Authors: Kanamori Kan , Kunita Noriko , Okamoto Ken-ichi , Hidaka Jinsai
Published: August 2006

Two sulfatovanadium(III) complexes, trans-K3[VIII(ox)2(μ-SO4)] (1) and trans-K5[VIII(ox)2(SO4)2] (2), were prepared. The X-ray crystallography of complex 1 showed that the complex consists of a one-dimensional polymer chain with a bridging sulfate ion. In aqueous solution, however, the sulfate bridge is cleaved and the sulfate ion coordinates to vanadium(III) unidentately. Complex 2 has been characterized by elemental analysis, and Raman and infrared spectra.
A Phosphate Staining Reagent Revisited
Authors: Sankar N , Sahal Dinkar
Published: August 2006

A phosphate staining reagent [S. K. Goswami and C. F. Frey, J. Liquid Res., 12, 509 (1971)] was found to show differential staining of phosphate esters. Thus, the staining reaction mixtures in cases of molecules like dodecyl dihydrogenphosphate [DDP], phosvitin and phosphocellulose showed intense blue colors which on standing precipitated down leaving a colorless supernatant. However, at equimolar phosphate concentrations molecules like inorganic phosphate/diphosphate, ATP, and phosphoserine stained poorly. It was apparent that (a) the staining does not involve hydrolysis of phosphate esters and (b) the proximity between phosphate esters determines the staining intensity of different molecular systems. In order to confirm the proximity model, constant amounts of DDP were incubated with the staining reagent in the presence of increasing concentrations of sodium dodecyl sulfate [SDS]. A decrease in staining of phosphate was seen with progressive increase in the concentration of SDS. The slope of this inhibition curve was enhanced when the concentration of DDP was clamped at 300 μM (1 M = 1 mol dm−3) than was the case at 450 μM. The results of these experiments are suggestive of competitive binding of SDS to aggregates of DDP, a phenomenon which decreases the proximity relationship between phosphate head groups of DDP. This has provided us a new method for the estimation of SDS and amphiphiles of similar kind which have the ability to alter proximity relations in DDP aggregates. Phosvitin, a phosphoprotein rich in clusters of intramolecular phosphate esters was only marginally sensitive to the presence of SDS for its staining by this reagent.
Enkephalin Alkylamides As Dimeric Probes for Bivalent Interaction with δ Opioid Receptors
Authors: Shimohigashi Yasuyuki , Tani Ayako , Ohno Motonori , Costa Tommaso
Published: August 2006

The bifunctional interaction of dimeric enkephalins with δ opioid receptors was evidenced by comparing activities between dimers and their monomeric alkylamide analogs having alkyl groups corresponding to the crosslinking spacer. When the tetrapeptide enkephalin amide H–Tyr–d-Ala–Gly–Phe–NH2 was alkylated by a dodecyl group, the resulting enkephalin dodecylamide exhibited only 7—15% activities of those of the nonalkylated amide in the μ assays (muscle assay in guinea pig ileum and rat brain binding assays using [3H]naloxone or [3H]–[d-Ala2,MePhe4,Gly-ol5]enkephalin) and 6—48% activities in the δ assays (muscle assay in mouse vas deferens and binding assays using [3H]–[d-Ala2,d-Leu5]enkephalin or [3H]–[d-Ser2,Leu5]enkephalyl-Thr6). DTE12, a dimer of the structure (H–Tyr–d-Ala–Gly–Phe–NH–(CH2)6–)2 which is created structurally by linking the second tetrapeptide enkephalin molecule to the dodecyl group of enkephalin dodecylamide, was almost as active as enkephalin dodecylamide in the μ assays. However, its δ activities were drastically enhanced, showing 57-fold increase in activity in the muscle assay and 33-fold increase in the brain binding assays when compared with the dodecylamide monomer. Similar results were also obtained for a set of pentapeptide enkephalins; i.e., enkephalin amide H–Tyr–d-Ala–Gly–Phe–Leu–NH2, its ethylamide analog and crosslinked dimer DPE2. The results indicated that the presence of the second peptide in the dimeric enkephalin molecule is responsible for most of increase in biological activities and receptor selection, and that the dimeric enkephalin functions as bivalent ligands for δ receptors.
Preparation and Some Properties of Linear-Type S-Bridged IrIIICoIIIIrIII Trinuclear Complexes with 2-Aminoethanethiolate (aet) or l-Cysteinate (l-cys). Crystal Structure of ΔΛ-[Co{Ir(aet)3}2](NO3)3
Authors: Konno Takumi , Nakamura Kenji , Okamoto Ken-ichi , Hidaka Jinsai
Published: August 2006

The reactions of newly prepared fac(S)-[IrIII(aet)3] or ΔLLL-fac(S)-[IrIII(l-cys-N,S)3]3− with Co2+, followed by the air or H2O2 oxidation, gave linear-type S-bridged trinuclear complexes, [CoIII{IrIII(aet)3}2]3+ and ΔLLLΔLLL-[CoIII{IrIII(l-cys-N,S)3}2]3−. The aet trinuclear complex was separated and optically resolved into the ΔΛ, ΔΔ, and ΛΛ isomers and the crystal structure of the ΔΛ isomer was determined by X-ray diffraction. [Co{Ir(aet)3}2](NO3)3·2H2O, chemical formula C12H40N9S6O11CoIr2, crystallizes in the triclinic, space group with a = 8.945(2), b = 12.073(3), c = 8.849(3) Å, α = 110.36(2), β = 102.55(2), γ = 70.88(2)°, U = 841(2) Å3, Z = 1, and R = 0.059. The central Co(III) has a trigonally distorted octahedral geometry, coordinated by six thiolato sulfur atoms from the octahedral Δ- and Λ-fac(S)-[Ir(aet)3] terminals. The other trinuclear complexes were characterized by their absorption, CD, and 13C NMR spectra. The meso–racemic isomerization, which results from the cleavage of the Co–S bonds, was recognized for [Co{Ir(aet)3}2]3+ in D2O, methanol–H2O, and ethanol–H2O. The cyclic voltammogram of rac-[Co{Ir(aet)3}2]3+ in water showed two almost reversible redox couples at −0.23 V and +0.73 V (vs. Ag/AgCl). The chemical properties of the present IrIIICoIIIIrIII complexes are discussed in comparison with those of the corresponding RhIIICoIIIRhIII and CoIIICoIIICoIII complexes.
Diastereoselectivity in the Preparation of 4-Phenylthio-4-butanolide Derivatives by the Use of the Pummerer Rearrangement
Authors: Su Huiwen , Hiwatari Yuichi , Soenosawa Masanobu , Sasuga Kenji , Shirai Kozo , Kumamoto Takanobu
Published: August 2006

Diastereoselectivity in the preparation of 4-phenylthio-4-butanolide derivatives by the Pummerer rearrangement of 4-phenylsulfinylbutanoic acid derivatives was clarified. The reaction of 3-alkyl-4-phenylsulfinylbutanoic acid with acetic anhydride resulted in the predominant formation of trans-3-alkyl-4-phenylthio-4-butanolide. Lactonization of 2,3-dialkyl-4-phenylsulfinylbutanoic acid gave (2RS,3RS, 4SR)-2,3-dialkyl-4-phenylthio-4-butanolide predominantly.
Chemical Interactions between 1,2,4-Triazole-3-thiols and π-Acceptors
Authors: Hassan Alaa A , Mohamed Nasr K , Ibrahim Yusria R , Sadek Kamal U , Mourad Aboul-Fetouh E
Published: August 2006

4-Amino-5-mercapto-5-substituted 4-amino-1,2,4-triazole-3-thiols 1a, b reacted with tetrachloro-, tetrafluoro-p-benzoquinone and 2,3-dichloro-1,4-naphthoquinone as well as 2-(dicyanomethylene)-1,3-indandione via charge-transfer (CT) complex formation giving naphthotriazolothiadiazinone 2a—d, bistriazolobenzobisthiadiazine 3a—d, triazolobenzothiadiazinone 4a, b, bistriazolonaphthobisthiadiazine 5a, b, and indenatriazolothiadiazepine 7a, b derivatives.
New Synthetic Methods and Reagents for Complex Carbohydrates. VII. Syntheses and Glycosylation Reactions of Glycopyranosyl Dimethylphosphinothioate Series Having a Nonparticipating Group at the C-2 Position
Authors: Yamanoi Takashi , Nakamura Kazumi , Sada Shuji , Goto Masahiro , Furusawa Yoji , Takano Masaaki , Fujioka Ayumi , Yanagihara Kenji , Satoh Yuzuru , Hosokawa Hideaki , Inazu Toshiyuki
Published: August 2006

Several glycopyranosyl dimethylphosphinothioates having a nonparticipating group at the C-2 position could be easily prepared by reactions of the corresponding glycopyranose and dimethylphosphinothioyl chloride using butyllithium as a base in tetrahydrofuran. These dimethylphosphinothioates are stable at room temperature and gave the corresponding α-glycosides, predominantly in good yields, by reactions with alcohols using silver perchlorate as an activator in the presence of molecular seives 4A in benzene at room temperature. Also, the combined use of iodine and a catalytic amount of triphenylmethyl perchlorate was effective for this glycosidation as a new activating system instead of silver perchlorate. Further, the synthetic intermediates of H-disaccharide and the Lewis X antigen were prepared using the present method.
Optical Resolution of 2- and 3-Hydroxyalkyltriphenylphosphonium Salts. Stereoselective Synthesis of Enantiomerically Pure (E)- and (Z)-Homoallylic Alcohols
Authors: Okuma Kentaro , Tanaka Yuichiro , Ohta Hiroshi , Matsuyama Haruo
Published: August 2006

Optically active 2- and 3-hydroxyalkyltriphenylphosphonium salts were prepared by the optical resolution of their 2,3-di-O-benzoyltartrates. The reaction of these salts with butyllithium afforded the corresponding ylides, which reacted with aldehydes to give optically active (E)-homoallylic alcohols in good yields. 3-Hydroxyalkyltriphenylphosphonium salts were converted into the corresponding diphenylphosphine oxides by the reaction with aq NaOH, which reacted with sodium hydride followed by the addition of benzaldehyde to afford optically active (Z)-homoallylic alcohols.
Intramolecular Interaction of Porphyrin Moieties in 2,5-Piperazinedione-Bridged Porphyrin Dimers
Authors: Tamiaki Hitoshi , Suzuki Shinji , Maruyama Kazuhiro
Published: August 2006

Diastereomerically pure 2,5-piperazinedione-bridged meso-tetraarylporphyrin dimers were synthesized with easy procedures. 1H NMR, UV-vis, and CD spectra showed that porphyrin moieties in the l,l-molecule interacted more strongly than those in the d,l-isomer and this interaction decreased with substitution by 3,5-di-t-butyl groups on the meso-phenyl substituents.
Synthesis of Asperuloside Aglucon Silyl Ether and Garjasmine from (+)-Genipin via Gardenoside Aglucon Bis(silyl ether) as a Common Intermediate
Authors: Nakatani Kazuhiko , Shimano Kazunori , Hiraishi Atsushi , Han Qingjun , Isoe Sachihiko
Published: August 2006

Syntheses of C6-functionalized iridoids represented by asperuloside aglucon silyl ether (4) and garjasmine were accomplished from (+)-genipin by utilizing the gardenoside aglucon bis(silyl ether) (3) as a common intermediate. During the transformation of 3 into 4, the acid-catalyzed transposition reaction of the tertiary hydroxyl group was found to proceed from more hindered concave side to give C6-hydroxylated compound having the same stereochemistry as that of C6 in 4. This observed hydroxyl group transposition reaction was interesting since such migration of hydroxyl group in the proposed biosynthetic pathway of gardenoside from geniposide proceeded to the opposite direction.
A Sensitive Fluorometric Assay for Activity of Pepsin
Authors: Yonezawa Hiroo , Yamada Kazuhiko , Uchikoba Tetsuya , Kaneda Makoto
Published: August 2006

Fluorogenic substrates of pepsin; Dns–Ala–Ala–Phe–Trp–Val–Leu–OCH2Py (I), Ala–Ala–Trp–Phe–Leu–NHNHDns (II), and Ala–Ala–Trp–Phe–NHNHDns (III) were synthesized by a solution method and their properties were compared with Dns–Ala–Phe–Trp–Val–Leu–OCH2Py (IV). The synthetic substrates I and II were cleaved specifically between Phe and Trp residues by pepsin and increased the fluorescence, although, the substrate III was not hydrolyzed by pepsin. The hydrolysis rates of the substrates by pepsin were measured by the increase in fluorescence.

The substrate I was hydrolyzed with pepsin by hundreds times faster than the substrates II and IV. The minimal detectable pepsin concentration of the substrate I was 0.5 nM and those of the substrates II and IV were 20 nM and 50 nM (M = mol dm−3). The substrates were sufficiently soluble in acidic buffers at their optimum pH. The inhibition rates of pepstatin and diazoacetyl-phenylalanine methyl ester for the activity of pepsin were measured by the use of the substrates IV and II. The activity of pepsin was inhibited by pepstatin within 15 s after mixing and by diazoacetyl-phenylalanine methyl ester within 120 s.

The resultant assay for pepsin is very sensitive and convenient and it is possible to determine rate of hydrolysis continuously.
Novel Adsorption and Desorption Chemiluminescence of 10,10′-Disubstituted 9,9′(10H,10′H)-Biacridinylidenes in Alumina Slurries
Authors: Yamada Sachiko , Maeda Koko
Published: August 2006

10,10′-Disubstituted 9,9′(10H,10′H)-biacridinylidene (1) has a novel chemiluminescence (CL) in an alumina slurry. The CL is yellowish green emissions I and II from the excited singlet state of adsorbed 1 onto alumina, 11*(ads), and blue emission III from the excited singlet state of 10-substituted 9(10H)-acridinone (2), 12*. In this study the effects of alumina activity and solvent polarity on the generation of those emitters were investigated and the mechanism was clarified: 1) 11*(ads) is generated by two-step electron transfers, the first electron transfer from 1 to O2 gives 1+•(ads) accompanied by adsorption of 1 and the following electron transfer from –OH and/or –O− on alumina to 1+•(ads) gives 11*(ads), and 2) 12* is generated from the reaction of 12+ and O2−•, both of which are formed during the reaction of emissions I and II. The two key compounds, 12+ and O2−•, were detected spectroscopically. O2−• in a slurry of 1, benzene, and highly activated alumina was found to be extremely stable and to generate 12* upon the addition of alcohol to the slurry. Then terms “adsorption chemiluminescence” for emissions I and II, and “desorption chemiluminescence” for emission III are proposed.
Studies of the Selective O-Alkylation and Dealkylation of Flavonoids. XV. A Convenient Synthesis of 3,5,6-Trihydroxy-7-methoxyflavones and Revised Structures of Two Natural Flavones
Authors: Tominaga Hideaki , Horie Tokunaru
Published: August 2006

A mixture of 6-hydroxy-3,4′,5,7-tetramethoxy- and 5,6-dihydroxy-3,4′,7-trimethoxyflavone was converted into 6-acetoxy-5-hydroxy-3,4′,7-trimethoxyflavone by acetylation and following dealkylation. The 3-methoxyl group in the tosylate of the 5-hydroxyflavone was selectively cleaved with anhydrous aluminum bromide in acetonitrile to give 6-acetoxy-3-hydroxy-4′,7-dimethoxy-5-(tosyloxy)flavone. 3,6-Dihydroxy-4′,7-dimethoxy-5-(tosyloxy)flavone, a deacetylated product of the flavone, was easily hydrolyzed to the desired 3,5,6-trihydroxy-4′,7-dimethoxyflavone in high yield via the corresponding 6-methoxymethyl ether. Eight 3,5,6-trihydroxy-7-methoxyflavones were synthesized by this method and their properties were clarified. Additionally, two 3,5,8-trihydroxy-7-methoxyflavones were synthesized by a similar method and the structures of two natural flavones which were proposed as 3,5,6-trihydroxy-7-methoxyflavone derivatives were revised to be 4′,7-dimethoxy- and 3′,4′,7-trimethoxy-3,5,8-trihydroxyflavones.
Preparation of Silole Derivatives and Their Reactions with Dimethyl Acetylenedicarboxylate
Authors: Terunuma Daiyo , Hirose Masashi , Motoyama Yuki , Kumano Kayo
Published: August 2006

Reaction of silole derivatives such as 1,1,3,4-tetramethylsilole (1)1) and 2,3-dimethyl-5-silaspiro[4.4]nona-1,3-diene (2) with dimethyl acetylenedicarboxylate (DMADC) were investigated. It was found that the reactions of 1 and 2 with DMADC in toluene gave 7-membered ring compounds; trimethyl 7-methoxy-3,3,3′,4′-tetramethyl-6-oxa-3-sila-1,2-benzocyclohepta-1,4-diene-4,5,6′-tricarboxylate and trimethyl 5-methoxy- 8,9-dimethylspiro[5H-4,1-benzoxasilepin-1,1′-silacyclopentane]-2,3,6-tricarboxylate, respectively.
Synthetic Photochemistry. LXI. A Total Synthesis of (±)-Valeranone, a cis-Decalone Sesquiterpenoid from Valeriana officinalis, via an Intramolecular Photocycloaddition
Authors: Takeshita Hitoshi , Cui Ying-She , Kato Nobuo , Mori Akira
Published: August 2006

Starting from the intramolecular [2+2] cycloaddition of 2,6-dimethyl-2-(3,4-dimethyl-3-cyclohexenyl)-4H-1,3-dioxin-4-one, (±)-valeranone, a cis-decalone sesquiterpenoid from Valeriana officinalis, was totally synthesized in stereoselective fashion.
Development of a Linker with an Enhanced Stability for the Preparation of Peptide Thioesters and Its Application to the Synthesis of a Stable-Isotope-Labelled HU-Type DNA-Binding Protein
Authors: Hojo Hironobu , Kwon Yeondae , Kakuta Yoshimitsu , Tsuda Sakae , Tanaka Isao , Hikichi Kunio , Aimoto Saburo
Published: August 2006

An S-alkyl-thioester-moiety-containing linker with an enhanced stability on a resin has been developed. A linker containing S-alkyl thioester with a spacer group, –CO–SC(CH3)2CH2CO–Nle–, was stable during the peptide chain elongation cycle. This thioester was stable under HF treatment conditions, and was rapidly activated by silver ions in the presence of N-hydroxysuccinimde (HONSu) to form a peptide bond. Using this linker, peptide segments covering the HU-type DNA-binding protein of Bacillus stearothermophilus (HBs), which was site-specifically labelled with 2H, 13C, and 15N, were prepared. Using these peptide segments, multi-labelled HBs was synthesized. Distinct signals of 2H, 13C, and 15N in HBs were detected by NMR spectrometry.
Syntheses and Spectral Properties of Norbornadiene-Fused Heterocycles: 1,3-Diphenyl-4,7-dihydro-4,7-methanobenzo[c]thiophene, -4,7-methano-2H-isoindole, and -4,7-methanoisobenzofuran
Authors: Kobayashi Tomoshige , Ono Katsuhiko , Suda Hirokazu , Yamashita Yoshiro , Kato Hiroshi
Published: August 2006

The syntheses of a novel diphenyl-substituted thiophene, pyrrole, and furan fused at the 3- and 4-positions with norbornadiene are described. Structures of these molecules are discussed on the basis of spectral properties by comparison with those of cyclohexene-fused derivatives. Single crystal X-ray structural analysis of the norbornadiene-fused thiophene as well as the PM3 calculations of the related compounds revealed that the bond angles of carbon atoms at the ring-junction of norbornadiene-fused heterocycles are distorted.
Synthesis of Optically Active Ferrocene Analogues of Salicylic Acid Derivatives and Rhodium(II)-Catalyzed Asymmetric Intramolecular C–H Insertion of α-Diazo β-Keto Esters Using New Chiral Carboxylato Ligands
Authors: Sawamura Masaya , Sasaki Hiroshi , Nakata Toshiki , Ito Yoshihiko
Published: August 2006

The ferrocene analogue of salicylic acid, 2-hydroxyferrocenecarboxylic acid was synthesized via monolithiation of ferrocene with t-butyllithium, and resolved to optically active forms. Optically active 2-hydroxyferrocenecarboxylic acid was converted to 1-hydroxyferrocenecarbaldehyde, ferrocene analogue of salicylaldehyde, and 2-alkoxyferrocenecarboxylic acids. The later compounds were used as chiral carboxylato ligands for the rhodium(II)-catalyzed asymmetric intramolecular C–H insertion of α-diazo β-keto esters (up to 42% ee).
Reaction of 2-Isoxazolines with Organolithiums in the Presence of Boron Trifluoride
Authors: Uno Hidemitsu , Terakawa Tetsuya , Suzuki Hitomi
Published: August 2006

In the presence of boron trifluoride, 3,4,5-tri-, 3,5,5-tri and 3,5-disubstituted 2-isoxazolines underwent nucleophilic addition of alkyl- and aryllithiums to give 3,3,4,5-, 3,3,5,5-, and 3,3,5-substituted isoxazolidines in moderate to good yields. On the other hand, in the case of 3,4,5,5-tetrasubstituted isoxazolines, the addition did not proceed at all but proton abstraction took place to afford a “ate” complex of isoxazoline anions, formation of which was confirmed by deuteration and the aldol reaction with benzaldehyde.
Stereochemical Control in Microbial Reduction. XXI. Effect of Organic Solvents on Reduction of α-Keto Esters Mediated by Bakers’ Yeast
Authors: Nakamura Kaoru , Kondo Shin-ichi , Kawai Yasushi , Ohno Atsuyoshi
Published: August 2006

Reduction of α-keto esters mediated by bakers’ yeast takes place in an organic solvent without immobilization of the microbe. Several factors such as water content, pH of the solution, amount of bakers’ yeast, and the property of the organic solvent affect to enantioselectivity of the reduction. In benzene, stereochemistry of the reduction shifts markedly toward preferential production of the (R)-α-hydroxy ester. The stereochemical consequence of the present reaction is accounted for by two factors; 1) the inhibition of enzymatic decomposition of the produced (R)-α-hydroxy ester in benzene and 2) the enhancement of relative activities of dehydrogenases or reductases in producing the (R)-α-hydroxy ester under dilute concentrations of the substrate at the vicinity of enzymes.
A Consideration of the Indirect Electrooxidation of Alkylbenzenes by Metal-Ion Mediators
Authors: Morita Masayuki , Masatani Tadahisa , Matsuda Yoshiharu
Published: August 2006

Selective oxidation of substituted alkylbenzenes to the corresponding aromatic aldehydes by metal-ion redox mediators has been investigated. The apparent oxidation potential of the substrate alkylbenzene (Es,ox) measured by voltammetry in an organic medium was used as a measure of the substrate reactivity. The oxidizing power of the mediator was also evaluated based on the apparent reduction potential in the voltammogram (Ered). The yields of the experimentally determined reaction products were explained by the mutual relation between Es,ox of the substrate and Ered of the mediator.
Ab Initio Triplet Potential Energy Curves of Methyl-Substituted Arylethylenes along the Double Bond Twisting
Authors: Segawa Katsunori , Takahashi Ohgi , Kikuchi Osamu , Arai Tatsuo , Tokumaru Katsumi
Published: August 2006

The potential energy curves of triplet states of β-methylstyrene (3) and 2-(1-propenyl)anthracene (4) were obtained by ab initio restricted open-shell Hartree–Fock (ROHF) calculations as a function of the twisted angle of the external double bond. The relative energies of trans, perpendicular, and cis forms of 4, t < p, c, support that the one-way isomerization occurs from cis to trans forms of 4.
Studies on Mixed Chelates. XXI. Synthesis and Crystal Structure of the Binuclear Nickel(II) Complex, μ-(Oxalato)bis[(acetylacetonato)(N,N,N′,N′-tetramethylethylenediamine)nickel(II)]
Authors: Yamada Kasumi , Fukuda Yutaka , Kawamoto Tatsuya , Kushi Yoshihiko , Mori Wasuke , Unoura Kei
Published: August 2006

A new binuclear nickel(II) complex having the formula [Ni2(acac)2(tmen)2ox] (acac = acetylacetonate, tmen = N,N,N′,N′-tetramethylethylenediamine, ox = oxalate) has been characterized, and its crystal structure has been determined at room temperature. This crystal was obtained in its solvated form, [Ni2(acac)2(tmen)2ox]·2TCE (where TCE = 1,1,2,2-tetrachroloethane); orthorhombic system, space group Pcab (No. 61), with a = 20.172(4), b = 17.180(5), c = 13.132(3) Å, Z = 4, R = 0.044. The oxalate ligand acts as a bridging group between the two Ni(II) moieties.
Novel Preparation of Disodium Amidophosphate Hexahydrate, Na2PO3NH2·6H2O, by the Reaction of Sodium cyclo-Triphosphate with Ammonia
Authors: Takenaka Atsushi , Yamanaka Shoji , Hattori Makoto
Published: August 2006

A reaction of sodium cyclo-triphosphate with ammonia at elevated temperatures gave water-insoluble sodium hydrogenamidophosphate, NaHPO3NH2. By treating the NaHPO3NH2 with a sodium hydroxide aqueous solution, disodium amidophosphate hexahydrate (Na2PO3NH2·6H2O) was obtained.
Optical Resolution of Amino Acids and Mandelic Acid by Complex Formation with Copper(II) Ion
Authors: Yamashita Hiroshi , Kayada Shin , Maekawa Takashi
Published: August 2006

The optical resolutions of amino acids and mandelic acid (MA) are done by complexation with copper(II). The optical purity of MA is the best when phenylalanine is used, i.e. 81%, and phenylglycine (PG) is well resolved by using l-MA with the optical purity of 74%. These results are interpreted in terms of the optical absorption energies of the copper(II) complexes in aqueous solution.
Anodic Oxidation of Active Methylene Groups in the Presence of Excess Carboxylic Acid
Authors: Koketsu Jugo , Kurita Masasi , Tamano Michiko , Fujimura Yoshikazu , Ando Fumio
Published: August 2006

The anodic oxidation of anthrone, (9,(10H)-anthracenone), 9,10-dihydroanthracene and 1-tetralone in acetonitrile was studied under the presence of excess carboxylic acids. The oxidation of anthrone with acetic acid gave anthraquinone, 10-acetoxyanthrone and 10-methyl-10-acetoxyanthrone. A similar reaction of anthrone with propionic acid yielded 10-propionyloxyanthrone. The electronic oxidation of 9,10-dihydroanthracene yielded anthraquinone, anthrone, and 9-acetoxyanthrone under the same conditions. Also, 1-tetralone reacted with acetic acid and propionic acid at the 4 position of the carbonyl group, giving 4-acetoxy- and 4-propionyloxy-1-tetralone, respectively.
Synthesis of New Unsymmetrical Multi-Sulfur TTF Derivatives
Authors: Ikegawa Shunjiro , Miyawaki Kenji , Nogami Takashi , Shirota Yasuhiko
Published: August 2006

Multi-sulfur TTF derivatives with eight or nine sulfur atoms were synthesized for the development of new conducting organic salts. Their oxidation potentials were measured, and compared with those of the related donor molecules. The electrical conductivities of some of the ion radical salts were measured.
Crystal and Molecular Structures of Octaisopropylcyclotetragermane, [(i-Pr)2Ge]4
Authors: Mochida Kunio , Kawajiri Yuko , Goto Midori
Published: August 2006

The crystal and molecular structures of octaisopropylcyclotetragermane, [(i-Pr)2Ge]4 have been determined by X-ray diffraction at room temperature. The triclinic structure was refined by the full matrix least-squares method to a final R = 0.049 for 5091 reflections. The Ge–Ge distances are in the range 2.47—2.48 Å. The Ge4 ring is nonplanar with a dihedral angle of ca. 17°. The Ge–Ge–C and C–Ge–C bond angles appear to bend away due to the steric repulsion of the isopropyl group.