bluuebunny/crossref_metadata_2025 huggingface dataset:
Molecular Magnets Based on Organic Charge Transfer Complexes
Authors: Enoki Toshiaki , Yamaura Jun-Ichi , Miyazaki Akira
Published: June 2006

Organic charge transfer complexes form a large variety of electronic structures from insulating state to metallic state in low-dimensional frameworks, which are governed by the competition between the transfer integral and the on-site Coulomb interaction. In the insulating regime, the generation of localized magnetic moments of π-electron origin provides low-dimensional magnetic systems having the features of quantum spins. The increase in the transfer integral which works to suppress the effect of on-site Coulomb interaction makes π-electrons delocalized, resulting in the appearance of the systems with the coexistence of magnetism and electron transport as materials classified around the Mott–Hubbard boundary. The introduction of localized magnetic moments of d-electrons in the complexes gives rise to the interaction between the π-electrons and the magnetic moments of d-electrons. Localized magnetic moments of d-electrons embedded in insulating complexes are expected to interact with each other through superexchange interaction mediated by the organic π-electron system, while localized d-spins in metallic complexes are coupled to each other via the π–d interaction, leading to the generation of molecule-based metal magnets. The studies of organic complex-based molecular magnets based on TTF-type donor molecules performed in our group are reviewed.
Behavior of Ruthenium Trisbipyridine–Anthraquinone Conjugates Connected with Alkyl Spacers in Homogeneous and Microheterogeneous Media
Authors: Otsuki Joe , Ogawa Hiroyuki , Okuda Naotoshi , Araki Koji , Seno Manabu
Published: June 2006

A series of mononuclear Ru trisbypiridine complexes connected to an anthraquinone unit by a flexible alkyl chain of varying lengths and a bolaamphiphilic dinuclear ruthenium complex bearing an anthraquinone unit in the middle of alkyl chain spacers were synthesized. Their conformational preference in CH3CN and in dihexadecyl phosphate vesicles was probed by utilizing the intramolecular electron-transfer quenching of the metal-to-ligand charge-transfer excited state of the Ru center by the appended quinone moiety. The length of the alkyl chain spacer had little effect on the quenching efficiency in either medium. A marked difference in the quenching behavior was observed only in the case of the dinuclear Ru complex in vesicles. These results indicate that the bolaamphiphilic structure is necessary and effective for the set of immobilized molecules to take a stretched conformation spanning a bilayer membrane.
The First Structurally Characterized Salen–Indium Complexes
Authors: Atwood David A , Jegier Jolin A , Rutherford Drew
Published: June 2006

In this manuscript are reported the synthesis and characterization of the first complexes of indium incorporating the acen and salen classes of ligands. This includes the compounds of formula LInMe (where L = acen (1) (N,N′-ethylenebis(2-hydroxy-α-methylbenzylidenimine)), salen (2) (N,N′-ethylenebis(2-hydroxybenzylideneimine)), salophen (3) (N,N′-(1,2-phenylene)bis(2-hydroxybenzylidenimine)), salomphen (4) (N,N′-(4,5-dimethyl-1,2-phenylene)bis(2-hydroxybenzylidenimine)). Attempts to prepare the derivatives, [In(R)(salpen)] (salpen = N,N′-propylenebis(2-hydroxybenzylidenimine), R = Me, Et) led to the formation of the bimetallic complexes, [(InMe2)2(salpen)] (5) and [In(Et2)2(salpen)] (6). Dissolution of 5 and 6 in MeOH causes the formation of three unusual products. They are the ligand bridged compounds [{In(μ-OMe)(μ-salpen)}2] (7), [{In(salpen)}2(μ-salpen)] (8) and the methoxy-only bridged complex, [{In(salpen)(μ-OMe)}2] (9). Compounds 7—9 are the first structurally characterized indium–salen complexes. For purposes of comparison, the structure of [{Al(salen)(μ-OMe)}2] (10) will also be described.
Successive Potentiometric Titration of Chromium(VI) and Iron(III) with Cobalt(II) in the Presence of 1,10-Phenanthroline
Authors: Katsumata Hideyuki , Teshima Norio , Kawashima Takuji
Published: June 2006

Studies are made on the effect of 1,10-phenanthroline (phen) on the redox reactions such as chromium(VI) and iron(III) with cobalt(II). In the presence of phen, the conditional redox potential of the Co(III)/Co(II) system is lower than that of the Cr(VI)/Cr(III) and the Fe(III)/Fe(II) systems. Two large potential breaks are thus observed at equivalence points when the titration of 5 × 10−4 mol dm−3 chromium(VI) and 1 × 10−3 mol dm−3 iron(III) with cobalt(II) is carried out in the presence of 8 × 10−2 mol dm−3 phen at pH 1, while in the absence of this ligand no potential break can be observed at equivalence points. By using these redox reactions, we propose successive potentiometric titrations of chromium(VI) and iron (III) with cobalt(II) in a single titration. The proposed method is successfully applied to the determination of chromium and iron in high carbon ferrochromium.
Synthesis of Dichloro(phthalocyaninato)antimony(V) Perchlorate, Tetrafluoroborate, and Hexafluorophosphate and Electrochemical Reinvestigation on the New Complex Salts
Authors: Kagaya Yutaka , Isago Hiroaki
Published: June 2006

The titled new salts were synthesized by exchanging the unknown counter anion of [Sb(pc)Cl2]+ salt (pc2− = phthalocyaninate, C32H16N82−), which was the first product of the reaction of phthalonitrile with antimony(III) trichloride, with perchlorate, tetrafluoroborate, and hexafluorophosphate. Elemental analytical data and infrared spectra of the new salts confirmed that these complexes are composed of one [Sb(pc)Cl2]+ cation and one mononegative counter ion. The introduction of electrochemically inactive counter-anions exerted little effect on the electronic spectrum and the first and second pc-ring reduction potentials of the complex in dichloromethane, but has made it possible to observe the third and fourth reduction processes, which were not observed for the initial salt. Up to four successive reduction processes of a pc-ring were observed for the first time in a noncoordinating solvent. Although the 1Δ2E1/2 (half-wave potential interval between the first and second reduction processes; 0.45 V), and 3Δ4E1/2 (0.58 V) values for [Sb(pc)Cl2]+ were typical of those for the known phthalocyanines, the 2Δ3E1/2 value (0.31 V) was much smaller. The anomaly in the spacing of the reduction processes for [Sb(pc)Cl2]+ is discussed in terms of the lack of a significant Jahn–Teller distortion of the pc-ring upon reduction.
Acid-Catalyzed [4+2] Cycloaddition Reaction of 2-(Alk-2-enyl)amino-3-(N-arylimino)methyl-4-oxo-4H-pyrido[1,2-a]pyrimidines
Authors: Noguchi Michihiko , Mizukoshi Takashi , Nishimura Shigeki
Published: June 2006

The N-arylimines of 2-(alk-2-enyl)amino-4-oxo-4H-pyrido[1,2-a]pyrimidine-3-carbaldehyde undergo the intramolecular [4+2] cycloaddition reaction under Lewis acid-catalyzed conditions to afford diastereomeric tetraazapentaphene derivatives. The diastereoselectivity as well as the scope and limitations of the cycloaddition reactions is discussed.
Linear and Stack Oligostreptocyanines. Effects of Relative Orientation of Chromophores on Redox Potentials of Dye Aggregates
Authors: Katoh Takashi , Inagaki Yoshio , Okazaki Renji
Published: June 2006

Linear and stack pentamethinestreptocyanine oligomers were prepared in which streptocyanines are covalently connected to each other. The absorption bands of the linear oligomers showed bathochromic shifts compared to that of the corresponding monomer, while the absorption band of the stack dimer was hypsochromically shifted. These spectral shifts were reproduced by a calculation with the INDO/S-CI method and are in agreement with those based upon a molecular exciton theory. The redox potentials of the linear oligomers underwent a positive shift due to the Coulombic interaction compared to those of the streptocyanine monomer. The positive shift of the reduction potential and the negative shift of the oxidation potential of the stack dimer are explained in terms of the Coulombic and orbital interactions.
Selectivity in Organic Group Transfer in Reactions of Mixed Diorganomanganese(II) and Triorganomanganate(II) with 2-Cyclohexen-1-one or Cyclohexanecarbaldehyde
Authors: Yorimitsu Hideki , Hayashi Yasuhiro , Tang Jun , Shinokubo Hiroshi , Oshima Koichiro
Published: June 2006

The unsymmetrical diorganomanganeses(II) (R1R2Mn) and magnesium triorganomanganates(II) (R12R2MnMgX) reacted with 2-cyclohexen-1-one to produce the 1,4-addition products in moderate to good yields. The approximate reactivity order obtained from the product distribution was CH2=CHCH2 > PhS > n-Bu > Ph > Me, Me3SiCH2, n-C6H13–C≡C. In contrast, the reactivity order for the addition of these reagents to cyclohexanecarbaldehyde was CH2=CHCH2 > Ph > Me > n-Bu > n-C6H13C≡C > Me3SiCH2.
Molecular Probing for the Microenvironment of Photonics Materials Prepared by the Sol–Gel Process
Authors: Matsui Kazunori , Nozawa Kazuhiro
Published: June 2006

The absorption and fluorescence spectra of the solvatochromic dye 9-diethylamino-5H-benzo[a]phenoxazin-5-one (Nile Red) were studied in modified SiO2 gels prepared from tetramethoxysilane (TMOS), tetraethoxysilane (TEOS), triethoxysilane (HTES), and triethoxymethylsilane (MTES). Nile Red showed a remarkable spectral shift during the sol–gel process, the direction and extent of which depended on the gel properties. ENT, empirical parameters of the solvent polarity, were determined based on the spectral shifts. As the precursors for the xerogels changed, ENT of the xerogels decreased in the order TEOS ≈ TMOS > MTES > HTES. ENT of the xerogels were 0.88—0.99 for TMOS and TEOS; this result showed the polarity of the xerogels form TMOS and TEOS to be almost the same as that of water (1.000). On the contrary, the polarity of the xerogels from HTES and MTES were as hydrophobic as haloalkane (0.1—0.3).
Zeolitic Membranes: Synthesis, Properties, and Prospects
Authors: Matsukata Masahiko , Kikuchi Eiichi
Published: June 2006

This article is intended to describe recent progress in the synthesis of zeolitic membranes and their permeation properties. While hydrothermal synthesis has been widely employed for zeolitic-membrane synthesis, the development of a new technique for zeolite synthesis, vapor-phase transport (VPT), has enabled us to prepare pinhole-free, zeolite-porous support composite membranes. This article consists of three sections that describe: a survey of the hydrothermal synthesis of zeolitic membranes, our synthesis results and the formation mechanism of zeolitic membranes by the VPT method as well as some permeation results to show the prospects of zeolitic membranes.
Hydrophobic Hydration Structures of Tris(1,10-phenanthroline)metal and Tris(2,2′-bipyridine)metal Complex Ions and Effect of the Ionic Charge. X-Ray Diffraction Study with Isomorphous Substitution
Authors: Yokoyama Haruhiko , Shinozaki Kazuteru , Hattori Shin , Miyazaki Fumiyo
Published: June 2006

X-Ray diffraction measurements have been made for aqueous solutions of sulfates or chlorides of [Ru(phen)3]2+, [Ni(phen)3]2+, [Ru(bpy)3]2+, [Ni(bpy)3]2+, [Rh(bpy)3]3+, and [Cr(bpy)3]3+ (phen = 1,10-phenanthroline, bpy = 2,2′-bipyridine). Radial distribution functions for the metal interactions were obtained by the isomorphous substitution between ruthenium(II) and nickel(II) complexes or between rhodium(III) and chromium(III) complexes. Metal–nitrogen and metal–carbon distances within the complex ions in solution were essentially in agreement with those in the crystals. Regarding the divalent metal complexes, about two water molecules seemed to exist at a distance of 3.5—3.6 Å (1 Å = 10−10 m) from the central metal atom and 10—11 water molecules existed in the region of 5.3 to 6.3 Å, probably in the vicinity of peripheral hollows along the C3 axis of the complex. Further, large broad peaks with high electron density were observed around 7.7 and 11.2 Å for the [Ru(bpy)3]2+ ion and around 8.0 and 11.5 Å for the [Ru(phen)3]2+ ion, almost independent of salt concentration and kinds of counter ions. These were attributed to the hydrophobic hydration shells having the hydrogen-bonded network structure. The hydration structure of the trivalent metal complexes was significantly different from that observed for the divalent ones: 14—15 water molecules existed in the range of 4.7 to 6.0 Å, a part of them presumably in the hollows along the C2 axes of the complex, and only a single broad peak was observed around 7.7 Å as the hydrophobic hydration shell. These results indicated that the hydrophobic hydration structure was reduced by the increase of the ionic charge, as predicted from a comparison of temperature coefficients of the Walden product obtained by the conductivity measurements of dilute solutions.
Charge-Transfer Complexes of Benzo[b]thiophene with σ- and π-Electron Acceptors
Authors: Ayad Mohamad M
Published: June 2006

The spectrophotometric properties of the charge-transfer (CT) complexes of benzo[b]thiophene with iodine at 24 °C in different solvents such as cychlohexane, carbon tetrachloride, chloroform, dichloromethane, and 1,2-dichloroethane are studied. In addition the spectrophotometric and thermodynamic properties of the CT complexes of benzo[b]thiophene with tetracyanoethylene, chloranil, 2,3-dichloro-5,6-dicyano-p-benzoquinone and 7,7,8,8,-tetracyanoquinodimethane are studied. The results show that the equilibrium and the thermodynamic parameters and the wavelengths of the maximum absorption bands (λmax) of the complexes vary markedly with the solvent. The ionization potential and the donor sites of benzo[b]thiophene are also determined and discussed.
Electrochemical Reduction Behavior of Alizarin Red S at HMDE in Aqueous Solutions
Authors: Abdel-Hamid Refat , Rabia Mostafa K , El-Sagher Hussein M
Published: June 2006

At hanging mercury-drop electrode (HMDE) Alizarin Red S (ARS) is electrochemically reduced in aqueous buffer solutions, giving rise to a prominent wave and a pre-wave. The prominent wave is diffusion-controlled and involves two electrons and two protons. The pre-wave is attributed to a strong reversible adsorption of the reduction product at the electrode. The reduction mechanism was proposed and discussed on the basis of the cyclic voltammetric and double potential-step chrono-amperometric & coulometric results. It was concluded that the reduction pathway is an ECEC mechanism in which the chemical reactions (C) are a dimerization of the formed radical anion and protonation of the dianion dimer, respectively. The rate-determining step is the protonation reaction. The adsorption process obeys a Langmuir isotherm with maximum surface excess of 1.4 × 10−10 mol cm−2 at a bulk concentration ≥4.6 × 10−5 mol dm−3, corresponding to 1.18 nm2/molecule. This indicates that ARS is horizontally oriented and resists reorientation upon increasing its bulk concentration.
π-Conjugation in Y-Shaped Configuration. Does a Special Stability Exist?
Authors: Ohwada Tomohiko , Kagawa Hirotaka , Ichikawa Hiroshi
Published: June 2006

The constrained HF method was applied to the estimation of conjugation of Y-shaped molecules. This method does not include the effect of the geometrical change, and gives a direct measurement of π-conjugation energy. We conclude that the magnitude of conjugation in a trimethylen–methane dianion is around that of a hexadienediide dianion, far less than that of a neutral cyclic aromatic compound (typically that of benzene). This is consistent with the previous conclusions obtained with the different energetic criteria. The physical meaning of Y-conjugation was interpreted in terms of relaxation of the kinetic-energy pressure of the π electrons.
Syntheses, Structures, and Properties of the Dinuclear Copper(II) and Nickel(II) Complexes Bridged by an Alkoxide and a Pyridazine or a Phthalazine
Authors: Li Chunmin , Kanehisa Nobuko , Miyagi Yoshie , Nakao Yasuo , Takamizawa Satoshi , Mori Wasuke , Kai Yasushi
Published: June 2006

In this paper we report our recent research on the dinuclear copper(II) and nickel(II) complexes 1—10 (Chart 1) containing Schiff bases, derived from acetylacetone, benzoylacetone, or trifluoroacetylacetone, and 1,3-diaminopropane-2-ol. These complexes are bridged by an alkoxide and a pyridazine (pyd) or phthalazine (phta). The magnetic susceptibilities, visible absorption spectra, conductivities, and redox properties of the complexes were investigated and the molecular structures of 2, 4, and 5 are described. The Cu–O–Cu angles found in these complexes indicate a role of the alkoxo-bridge as one of the principal antiferromagnetic exchange pathways. At the same time, the coplanarity of two coordination planes of copper(II) ions is also shown to relate to the exchange process.
Adsorption of Lead(II) Ion on Complexane Types of Chemically Modified Chitosan
Authors: Inoue Katsutoshi , Ohto Keisuke , Yoshizuka Kazuharu , Yamaguchi Tomoo , Tanaka Takeshi
Published: June 2006

Two kinds of complexane-type of chitosan chemically modified with EDTA and DTPA were synthesized and examined concerning the adsorption behavior for iron(III), copper(II), nickel(II), zinc(II), aluminium(III), and lead(II) from a dilute hydrochloric acid solution. Both of these adsorbents were found to adsorb lead(II) at low pH in a similar highly selective manner over zinc regardless of the kind of acid, whether it be hydrochloric acid or nitric acid, and to have a much stronger adsorption power compared with a commercial phosphonamidic acid-type chelating resin. The maximum adsorption capacities of lead were 1.8 and 1.5 mol/kg-dry gel for DTPA- and EDTA-chitosan. The breakthrough followed by elution tests demonstrated that it is achievable to concentrate a small amount of lead(II) which has been very selectively separated from a large excess of zinc by using an adsorption column packed with these adsorbents.
The Response Behavior of a Polyacrylamide–Benzo-15-C-5 Electrode to Sodium and Calcium Ions in Acetonitrile and Its Application to the Study of Their Complexing with Other Basic Aprotic Solvent Molecules
Authors: Nakamura Toshio , Mongi Hideyuki
Published: June 2006

The response behaviors of an ionophore-conjugated polymer-based ion sensor, which consists of a polyacrylamide (PAA) coupled to benzo-15-crown-5 (B15C5), for Na+ and Ca2+ in acetonitrile (AN) and N-methylpyrrolidinone (NMP) were studied. The PAA–B15C5 electrode showed a Nerstian response to Na+ in AN and Ca2+ in AN and NMP. The electrode was then applied to investigate the complexation of Na+ in AN with such other solvent molecules (D) as N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO); the successive complex formation constants and Gibbs energies of transfer of Na+ in AN to DMF or DMSO and AN to AN–D mixtures were obtained. Reasonable responses of the electrode to an activity change of Na+ due to the solvation of the basic solvent molecules could be certified. The complex formation constant of Ca2+ in AN with such D as DMF, NMP, N,N-dimethylacetamide (DMA), DMSO and hexamethylphosphoric triamide could be obtained by the electrode. The association constants of Ca2+ with CF3SO3− in AN, propylene carbonate, DMF, and DMSO were determined conductometrically and the constant in AN (K1AN = 1.02 × 104 dm3 mol−1) was used for correcting the variation of calcium ion-activity due to a concentration change of Ca(CF3SO3)2 in AN.
Growth of Chlorapatite Crystals from a Sodium Chloride Flux
Authors: Oishi Shuji , Sugiura Isao
Published: June 2006

Well-formed crystals of chlorapatite [Ca5Cl(PO4)3] were first grown from a sodium chloride flux. The solubility of Ca5Cl(PO4)3 in NaCl increased with increasing temperature. At 1100 °C, Ca5Cl(PO4)3 had a solubility of about 0.15 mol%. The crystal growth of Ca5Cl(PO4)3 was conducted by heating a mixture of solute and flux at 1100 °C for 10 h, followed by cooling to 500 °C at a rate of 5 °C h−1. Colorless and transparent crystals having lengths up to 4.0 mm and widths of 1.2 mm were grown from high-temperature solutions containing small amounts of solute (0.05—0.5 mol%). The obtained crystals were divided into two distinct morphological types: prisms and needles. The most suitable solute contents for the growth of prismatic and needle crystals were 0.15 and 0.1 mol%, respectively. The crystal forms were also dependent on the solute content. The prismatic crystals were bounded by the {} and {} faces. The needle crystals elongated in the <0001> directions. Calcium, chlorine, phosphorus, and oxygen were almost homogeneously distributed in the crystals.
Synthesis and Structural Characterization of Manganese(II) Complexes with N,N′-Bis(2-pyridylmethylene)-1,3-diaminopropan-2-ol or N,N′-Bis(2-pyridylmethylene)-1,3-propanediamine
Authors: Mikuriya Masahiro , Hatano Yasushi , Asato Eiji
Published: June 2006

Manganese(II) complexes with N,N′-bis(2-pyridylmethylene)-1,3-diaminopropan-2-ol (HL1) or N,N′-bis(2-pyridylmethylene)-1,3-propanediamine (L2), [Mn(HL1)(NO3)2] (1) and [Mn(HL1)(NCS)2] (2), [Mn(HL1)(phen)](ClO4)2 (3), [Mn2(L1)(CH3COO)(phen)2](ClO4)2 (4), [Mn(L2)(NO3)2] (5), [Mn(L2)(bpy)(CH3OH)](ClO4)2 (6), [Mn(L2)(NCS)2] (7), [Mn(L2)(phen)](ClO4)2 (8), have been synthesized and characterized by measurements of the infrared, electronic, and ESR spectra, and magnetic susceptibilities. The molecular structures of these complexes were determined by the single-crystal X-ray structure analysis. The complexes 1·C2H5OH and 5 have an eight-coordinated manganese atom with a square antiprism geometry. The complex 6 is seven-coordinated in a monocapped trigonal prism. The manganese atoms of 2, 7, and 8 are six-coordinated in a trigonal prism environment. The coordination environment of 3 is disordered between the seven- and six-coordinate geometries. The complex 4·H2O is a dinuclear molecule comprising two octahedral Mn(II) atoms.
Synthesis of Macrocyclic Bis(dithiocarbonic ester)s and Bis(thiocarbamate)s from Diethylene, Triethylene, and Tetraethylene Glycols
Authors: Fukada Naoaki , Tanaka Takashi , Fukuya Tetsuo , Takeda Yasuyuki
Published: June 2006

The reaction of dipotassium bis(dithiocarbonate)s from diethylene, triethylene, and tetraethylene glycols with dibromoalkanes or ethereal oxygen-containing diiodides under high-dilution conditions gave 1 : 1 reaction products, 14—25-membered macrocyclic bis(dithiocarbonic ester)s. From dimethyl esters of the bis(dithiocarbonic acid)s and diaminoalkanes or ethereal oxygen-containing diamines, macrocyclic bis(thiocarbamate)s were obtained.
Novel Water-Soluble Organosilane Compounds as a Radical Reducing Agent in Aqueous Media
Authors: Yamazaki Osamu , Togo Hideo , Nogami Genki , Yokoyama Masataka
Published: June 2006

The development of novel water-soluble organosilane compounds and their application to radical reactions in water medium have been studied. A series of novel organosilane compounds having hydrophilic groups, such as an ether group and a hydroxy group in the side chain to bear hydrophilicity, were synthesized by the reaction of trichlorosilane or tetrachlorosilane and Grignard reagents. The reactivities of these organosilane compounds were studied in the radical reduction of 2-bromoethyl phenyl ether in ethanol in the presence of triethylborane under aerobic conditions. The results showed that diarylsilane was the most effective among them. The radical reduction of alkyl and aryl halides with diarylsilane was applied to a reaction in aqueous media, which gave the corresponding reduction product in good yields. Thus, the present organosilanes are very useful for the reduction of water-soluble substrates, such as halo sugars in water.
Oxidation of Diols and Ethers by NaBrO3/NaHSO3 Reagent
Authors: Sakaguchi Satoshi , Kikuchi Daisuke , Ishii Yasutaka
Published: June 2006

NaBrO3 combined with NaHSO3 was found to be an excellent oxidizing reagent of alcohols, diols, and ethers under mild conditions. A variety of aliphatic and cyclic diols were selectively oxidized with satisfactory yields to the corresponding hydroxy ketones and/or diketones, which are difficult to selectively prepare due to a concomitant formation of cleaved products. For example, 2-hydroxycyclohexanone and 1,2-cyclohexanedione were selectively formed by allowing 1,2-cyclohexanediol to react with NaBrO3/NaHSO3 reagent in a selected solvent. On the other hand, an alkyl ether, such as dioctyl ether, reacted with NaBrO3/NaHSO3 in water at room temperature to give octyl octanoate in 82% yield. The same oxidation at higher temperature (60 °C) produced the α-brominated ester, octyl 2-bromooctanoate, which is considered to be formed through an alkenyl alkyl ether as the intermediate. The treatment of 1-ethoxy-1-heptene with NaBrO3/NaHSO3 afforded ethyl 2-bromoheptanoate and 2-bromoheptanoic acid as the major products.
Preparation of Inorganic–Organic Nanocomposites through Intercalation of Organoammonium Ions into Layered Silicates
Authors: Ogawa Makoto , Kuroda Kazuyuki
Published: June 2006

Recent developments in the study of the intercalation of organoammonium ions into layered silicates are reviewed. The new developments of the applications of the organoammonium-exchanged layered silicates include the selective adsorption of toxic compounds from water, the immobilization of photo and electroactive species to construct novel photo and electrofunctional materials, and the complexation with organic polymers for the enhancement of the mechanical properties. The conversion of the layered solids to three dimensional nanoporous solids with novel microstructures and adsorptive properties has also been successfully done. The novel controlled properties achieved by the modification with the adsorption of organoammonium ions open new opportunities to tailor the properties of the inorganic-organic nanostructured materials.
Study on the Photolysis Quantum Yield of Diphenyl Disulfide by the Transient Grating Method
Authors: Kimura Yoshifumi , Sugihara Kohei , Terazima Masahide , Hirota Noboru
Published: June 2006

Transient grating (TG) spectroscopy, photoaccoustic spectroscopy, and transient adsorption spectroscopy have been applied to studying the nongeminate recombination of photodissociated diphenyl disulfide (DPDS) in liquids. The photolysis quantum yield can be easily determined by an analysis of the time profile of the thermal grating signal, if the contribution of the population grating can be neglected. The quantum yield of the photodissociation for DPDS in isooctane has been determined to be 0.43 ± 0.02, which coincides with the values evaluated from the acoustic strength in the TG signal and the acoustic intensity in an ordinary photoacoustic measurement. This result is compared with a pico-second transient absorption measurement (T. W. Scott and S. N. Liu, J. Phys. Chem., 93, 1393 (1989)).
Charge Recombination via Electron Tunneling after Two-Photon Ionization of Dopant Chromophore in Poly(butyl methacrylate) Film at 20 K
Authors: Ohkita Hideo , Sakai Wataru , Tsuchida Akira , Yamamoto Masahide
Published: June 2006

The charge recombination of electron–cation pairs produced in a poly(butyl methacrylate) film through two-photon ionization was examined at 20 K by emission spectroscopy and absorption spectroscopy. Both the isothermal luminescence (ITL) decay and the absorbance decay of the radical cation obeyed the same kinetics at 20 K: the t−m law, I(t) ∝ t−m with m ≈ 1. The temperature dependence of the ITL decay kinetics remained the same from 20 to 200 K far below the glass-transition temperature (293 K). These findings show that the ITL decay at low temperatures can be explained in terms of a long-range electron transfer by electron tunneling. Multi-shot photoirradiation was found to cause a deviation of the ITL decay from the t−m law. Multi-shot photoirradiation probably induces a larger separation of a photoejected electron from the parent cation and/or a deepening of the trap depth.
Synthesis of 2,3-Dimethylbutenes by Dimerization of Propene Using Highly Active Nickel-Phosphine Catalysts in the Presence of Sulfonic Acids and/or Dialkyl Sulfates
Authors: Nomura Kotohiro , Ishino Masaru , Suzukamo Gohfu
Published: June 2006

A nickel-phosphine catalyst system consisting of nickel naphthenate, P(cyclo-C6H11)3, AlEt3, and 2,4,6-trichlorophenol (TCP) in the presence of sulfonic acids (CF3SO3H and MeSO3H) or dialkyl sulfates (Me2SO4 and Et2SO4) exhibits remarkable catalytic activity for the dimerization of propene. The catalytic activity (turnover number (TON) for the formation of C6 olefins or 2,3-dimethylbutenes) was enhanced when the catalyst was combined with effective additives, such as Et2SO4 and MeSO3H. The reaction products consisted of 2,3-dimethyl-1-butene (DMB-1) and/or 2,3-dimethyl-2-butene (DMB-2) in high yields (selectivity of dimers based on the reacted propene = 70—80%: selectivity of 2,3-dimethylbutenes in C6 olefins = 78—80%). The ratio of DMB-1/DMB-2 could be controlled by varying the molar ratios of the catalyst ingredients without decreasing in the turnover numbers. Although CF3SO3H was found to be the best additive as far as the catalytic activity and the selectivity of dimers (94—99%) are concerned, the selectivity of 2,3-dimethylbutenes in C6 olefins decreased. The addition of a small amount of water was also effective to enhance the catalytic activity: The turnover number for the formation of 2,3-dimethylbutenes was raised from 7050 to 30360.
A Novel Reaction of HCrO4− with PH2O2−, Induced by Molecular Oxygen, Forming Peroxodiphosphate Ions in an Aqueous Solution
Authors: Kimura Masaru , Takahashi Aki , Kayanoki Hiroko , Sakata Tomomi , Tsukahara Keiichi
Published: June 2006

The chromate (VI) ion HCrO4− at pH 2—4 was not appreciablly reduced by the phosphinate ion PH2O2− in the absence of molecular oxygen (O2), but was reduced in the presence of O2, forming peroxodiphosphate ions (denoted by PDP and meaning all forms of P2O84−, HP2O83− etc.) in much higher concentrations than those of the added chromate(VI). Both the rates of the chromate decay and the PDP formation increased with decreasing pH. When the chromate(VI) ion disappeared completely, PDP formation stopped and its concentration remained constant. However, such PDP once formed in the presence of O2 began to decompose after the solution was saturated with N2 gas; its decomposition ceased again when the solution was again saturated with air. Such behaviors are discussed while presenting the reaction mechanisms.
Mixed-Valence Ruthenium Diphosphates with a Tunnel Structure: ARu2(P2O7)2 (A = Li, Na, Ag, and Cu) and Ru2(P2O7)2
Authors: Fukuoka Hiroshi , Imoto Hideo
Published: June 2006

Mixed-valence ruthenium diphosphates with a tunnel structure, ARu2(P2O7)2 (A = Li, Na, Ag, and Cu), were prepared by the reaction of an amorphous ruthenium phosphate, H2RuP3O10, with Li2CO3, NaNO3, AgNO3, and Cu3(PO4)2·3H2O, respectively. The structure has a three-dimensional network constructed with RuO6 and P2O7 groups, and has large tunnels where A cations reside. In the sodium system, two isotypic compounds were obtained. One was obtained as single crystals and the X-ray structure analysis showed ruthenium and sodium vacancies. Another was obtained as powder and Rietveld analysis did not indicate ruthenium vacancies. It is paramagnetic and shows an antiferromagnetic transition at around 5.5 K. The phosphate with no cation in the tunnel, Ru2(P2O7)2, was obtained as a powder upon heating amorphous ruthenium phosphate (atomic ratio P/Ru is 4).
Roles of 2′-Hydroxyls of Leadzyme on an RNA Cleavage
Authors: Ohmichi Tatsuo , Sugimoto Naoki
Published: June 2006

The roles of two different 2′-hydroxyls near to a catalytic site of a leadzyme (Pb2+ ribozyme), CUGGGAGUCC, have been investigated kinetically. These roles of two different 2′-hydroxyls were clearly distinguished upon a cleavage reaction of an RNA substrate. One 2′-hydroxyl of G of the leadzyme in an asymmetry internal loop contributed to only the binding constant for the leadzyme with the substrates. The other 2′-hydroxyl of A in the asymmetry loop contributed to only the cleavage rate constant. On the basis of the results, we propose the possibility of the formation of a hydrogen bond between the 2′-hydroxyl of G of the leadzyme and the substrate and the binding between Pb2+ ion and the 2′-hydroxyl of A.
13C NMR and Electronic Absorption Spectroscopic Studies on the Equilibrium between the Colorless Lactone and the Colored Zwitterion Forms of a Fluoran-Based Black Color Former
Authors: Yanagita Mitsuhiro , Aoki Izuo , Tokita Sumio
Published: June 2006

The equilibrium between the colorless lactone (L) and the colored zwitterion (Z) forms of the fluoran compound 1, which has been widely used as a typical black color former in data-recording systems, has been studied by 13C NMR and electronic absorption spectroscopies. Fluoran 1 showed no visible absorption in aprotic solvents, while a black color appeared in phenolic solvents. The 13C NMR and signal of the spiro carbon of 1 in CDCl3 appeared at 84.2 ppm, indicating that 1 exists substantially as L in aprotic solvents. In phenol d6 at 50 °C, the signal of the spiro carbon in 1 shifted to a lower magnetic field and appeared in the sp2-hybridization region (δ = 162.7), suggesting that in phenol-d6 a cleavage of the C(spiro)–O bond in the lactone ring occurs and that the ring-opened Z form is produced. The equilibrium between L and Z depended strongly on the temperature and solvents. The high temperature and inhibition of the solute (1)–solvent interaction by steric hindrance, self-association and intramolecular chelation of the solvent shifted the L–Z equilibrium toward L. The thermodynamic parameters for the equilibrium reaction in phenolic solvents were also estimated.
Ring Expansion and Ring Contraction Observed in Isopropenyldihydrofuran Derivatives
Authors: Yamaguchi Seiji , Sugioka Yoshihiko , Kitagawa Yuzoh , Matsumoto Yoshinori , Yokoyama Hajime , Hirai Yoshiro
Published: June 2006

An intramolecular anhydride formation in 5-isopropenyl-4,5-dihydrofuran-2,3-dicarboxylic acid caused a new ring expansion to give 4,7-dihydro-6-methyloxepin-2,3-dicarboxylic anhydride (2b). An aminolysis of 2b with benzylamine gave a mixture of two isomeric carboxamides, N-benzyl-4,7-dihydro-6-methyloxepin-2-carboxamide and trans-1-(benzyloxamoyl)-2-isopropenylcyclopropane. Also, the ring expansion and ring contraction are discussed.
Effects of Solvent Molecular Size on Rates of Topomerization in Organolithium Compounds
Authors: Oki Michinori , Ikeda Hiroshi , Kodama Kazuya , Toyota Shinji
Published: June 2006

Rates of topomerization of substituted 9-fluorenyllithiums and α-(benzylthio)benzyllithium were determined in various ether-type solvents by the dynamic NMR technique. The rates are small in solvents of bulky molecules in comparison with those of less-bulky molecules. UV-vis spectra of these compounds in the solvents indicate that the compounds tend to exist as solvent-separated ion pairs in solvents of small molecular size, whereas they exist as contact ion pairs in solvents of bulky molecules. 1H NMR spectra did not show signals attributable to two species at the lowest temperature of study. From these results, it is concluded that the observed process is the tumbling of the anion in solvent-separated ion pairs with a rapid pre-equilibrium between contact ion pairs and solvent-separated ion pairs, further intervention of solvent molecule(s) into the observed solvent-separated ion pairs being the rate-limiting step. A term, dimensiosolvatic effect, is proposed for the effects where the solvent molecular size plays important roles in determining rates of reaction or equilibria.
Trans-Chelating Chiral Peralkyldiphosphine Ligands (R,R)-(S,S)-2,2″-Bis[1-(dialkylphosphino)ethyl]-1,1″-biferrocenes (AlkylTRAPs) and Their Transition Metal Complexes
Authors: Kuwano Ryoichi , Sawamura Masaya , Okuda Satoshi , Asai Tomohito , Ito Yoshihiko , Redon Martine , Krief Alain
Published: June 2006

New chiral peralkyldiphosphines (S,S)-2,2″-bis[(R)-1-(dialkylphosphino)ethyl]-1,1″-biferrocenes ((R,R)-(S,S)-alkylTRAPs) were synthesized from (R)-N,N-dimethyl-1-ferrocenylethylamine in four steps in 38—68% overall yields (MeTRAP: 38%, EtTRAP: 68%, PrTRAP: 53%, BuTRAP: 56%, i-BuTRAP: 51%, i-PrTRAP: 42%). The reactions of alkylTRAP (Et-, Bu-, i-Bu, and i-PrTRAP) with 1 molar amount of PdBr2 gave trans-[PdBr2(alkylTRAP)] in good yields. The X-ray crystal structures of these palladium complexes revealed that alkylTRAPs coordinated to a palladium atom in a trans-chelating manner regardless of the P-alkyl substituents. The structures of palladium complexes of Et-, Bu-, and i-PrTRAP had nearly C2-symmetry, but that of i-BuTRAP was deviated from C2-symmetry significantly. AlkylTRAPs also reacted with [PtCl2(MeCN)2] and [RhCl(CO)2]2, giving the corresponding trans-chelate platinum and rhodium complexes. The crystal structure of trans-[RhCl(CO)(BuTRAP)] revealed that the conformation of the BuTRAP ligand in the complex was almost the same as that in the palladium complex trans-[PdBr2(BuTRAP)].
Gelation of Fluoroalkylated End-Capped Oligomers Containing Triol Segments under Non-Crosslinked Conditions, and Binding or Releasing of Metal Ions by These Oligomers
Authors: Sawada Hideo , Nakamura Yutaka , Katayama Shinsuke , Kawase Tokuzo
Published: June 2006

New fluoroalkylated end-capped oligomers containing triol segments were prepared by the reactions of N-tris(hydroxymethyl)methylacrylamide and fluoroalkanoyl peroxides. Under the non-crosslinked conditions, these fluoroalkylated oligomers were found to cause a gelation, where the aggregations of fluoroalkyl segments and the hydrogen-bonding interaction are involved in establishing a physical gel network not only in water, but also in organic solvents. Therefore, it was demonstrated that the aggregation of the end-capped fluoroalkyl segments in water and/or in organic media become a new driving factor for gelation as well as such well-known interactions as the hydrogen bond and ionic interaction. These thus-obtained fluorinated oligomer hydrogels had a high Cr3+ or Co2+ binding power, and the metal ions were easily released from the metal ions-bound oligomers into water.
Ribosomal protein S1 promotes transcriptional cycling
Authors: Sukhodolets Maxim V. , Garges Susan , Adhya Sankar
Published: June 2006

Prokaryotic RNA polymerases are capable of efficient, continuous synthesis of RNA in vivo, yet purified polymerase-DNA model systems for RNA synthesis typically produce only a limited number of catalytic turnovers. Here, we report that the ribosomal protein S1—which plays critical roles in translation initiation and elongation in Escherichia coli and is believed to stabilize mRNA on the ribosome—is a potent activator of transcriptional cycling in vitro. Deletion of the two C-terminal RNA-binding modules—out of a total of six loosely homologous RNA-binding modules present in S1—resulted in a near-loss of the ability of S1 to enhance transcription, whereas disruption of the very last C-terminal RNA-binding module had only a mild effect. We propose that, in vivo, cooperative interaction of multiple RNA-binding modules in S1 may enhance the transcript release from RNA polymerase, alleviating its inhibitory effect and enabling the core enzyme for continuous reinitiation of transcription.
Development and Performance Evaluation of a Tandem Mass Spectrometry Assay for 4 Adrenal Steroids
Authors: Kushnir Mark M , Rockwood Alan L , Roberts William L , Pattison Elizabeth G , Owen William E , Bunker Ashley M , Meikle A Wayne
Published: June 2006

Background: Congenital adrenal hyperplasia is a group of autosomal recessive disorders caused by a deficiency of 1 of 4 enzymes required for the synthesis of glucocorticoids, mineralocorticoids, and sex hormones. Analysis of 11-deoxycortisol (11DC), 17-hydroxyprogesterone (17OHP), 17-hydroxypregnenolone (17OHPr), and pregnenolone (Pr) in blood allows detection of these enzyme defects.

Methods: The steroids were extracted from 200 μL of serum or plasma by solid-phase extraction, derivatized to form oximes, and extracted again with methyl t-butyl ether. Instrumental analysis was performed on an API 4000 tandem mass spectrometer with electrospray ionization in positive mode and multiple reaction-monitoring acquisition.

Results: The limits of detection were 0.025 μg/L for 11DC, 17OHP, and Pr and 0.10 μg/L for 17OHPr. The method was linear to 100 μg/L for 11DC, 17OHP, and Pr, respectively, and to 40 μg/L for 17OHPr. Within- and between-run (total) imprecision (CVs) were <7.1% and 11%, respectively. Reference intervals for children in Tanner stages 1 through 5 and adult males and females for 17OHP, 11DC, Pr, and 17OHPr were established. Prepared samples were stable for >72 h.

Conclusions: The detection limit and selectivity of this method and its small sample volume requirement allow analysis of endogenous concentrations of adrenal steroids in serum or plasma from children and adults. The method thus has an important potential role in the evaluation of the status of 4 of the enzymes involved in adrenal steroid biosynthesis.
X-ray Microdiffraction for the Analysis of Bearing Operation Conditions
Authors: Vegter RH , Verschoor HA , Girones A
Published: June 2006

The use of residual stress measurements for the analysis of the performance of rolling bearings has become a common tool in the bearing industry. The effects of rolling contact fatigue on the development of residual stresses in the loaded zones of a bearing has been investigated in much detail. In this paper, the developments of the use of X-ray microdiffraction for residual stress measurements in bearings will be described. In microdiffraction, measurements are performed with very small irradiated spots. Advances in X-ray diffraction technology have made it possible to determine the residual stresses in loaded components in small areas with a high level of detail. The method and its consequences for bearing analysis is discussed in this paper. Using the method, much more information on the exact operation conditions of a bearing can be extracted from the components compared to conventional X-ray diffraction methods. Residual stress measurements using microdiffraction have been successfully applied in an application analysis case, where the measurements were used to show the residual stress development in the bearing surface during operation. In such a case, microdiffraction could also be used to investigate local bearing life limiting features, such as surface damages.
If Ethics Committees were Designed for Ethnography
Authors: Tolich Martin , Fitzgerald Maureen H.
Published: June 2006

Where did the ethics review process go wrong for qualitative research, and how can we make it right, or at least better? This paper begins with an excerpt from an ethnography of attempting to attend an ethics review-related workshop, which exemplifies that the ethics-review process is based on epistemological assumptions aligned with positivistic research, and does not fit the qualitative research process. We suggest that a new format for ethics review, based on assumptions associated with qualitative research and ethnography, might be a better fit. In this model the researcher becomes the expert and the committee the learner or ethnographer. In this process the ethics review process is guided by four core open-ended questions that facilitate a fuller and richer exchange of information. The second part of this paper presents strategies that may lessen the risks associated with the unknown or emergent aspects of qualitative research. These strategies include a dual consent process and the co-opting of journal editors or thesis review boards to review ethical considerations prior to publication or sign off, and a renewed focus of ethics training.
Reduced Formalin and Hydrogen Peroxide Treatments during Walleye Egg Incubation
Authors: Soupir Craig A , Barnes Michael E
Published: June 2006

Formalin use was evaluated as part of an investigational new animal drug study to determine its effectiveness in controlling fungus (water molds: Saprolegniaceae) on incubating eggs of the walleye Sander vitreus. Hydrogen peroxide was also evaluated as an egg treatment alternative to formalin. In total, three antifungal chemical treatment regimes (15 min daily) were evaluated during this study. Eggs were treated with 200 mg of hydrogen peroxide/L of water, 834 mg formalin/L, and the industry standard of 1,667 mg formalin/L. Untreated control eggs were severely infested with fungus and experienced survival to hatch that was significantly lower than that of the chemically treated eggs. Formalin and hydrogen peroxide treatments both controlled fungus and produced similar egg survival to initial hatch. However, walleye egg survival was significantly greater in jars treated with 1,667 mg formalin/L than in any other treatment. This study provided important new data on the use of chemical treatment concentrations lower than the standard of 1,667 mg formalin/L or 500 mg hydrogen peroxide/L to control fungus on incubating walleye eggs.
Transport impacts of household waste recycling centres
Authors: Maynard S. J. , Cherrett T.
Published: June 2006

Household waste recycling centres (HWRCs) evolved from civic amenity sites (CAS) introduced by the Civic Amenities Act 1967, and provide householders with an outlet for the disposal of a wide range of materials. Sites are now handling significant volumes of recyclables (66% of total household recyclables), and the transport impacts associated with increasing visitor numbers to HWRCs are of interest to traffic managers and land use planners. The transport logistics associated with servicing sites, including the collection, treatment and disposal of different materials, is complex. The reduction in landfill disposal coupled to more stringent requirements for material recycling and treatment has resulted in short journeys from HWRCs to landfill being replaced by complex road trips to different facilities at various locations. The operational, environmental and social impacts associated with these potential increases in commercial transport activities can be quantified through modelling current and projected fleet operations under various future scenarios. This can be achieved through routing and scheduling applications, which can be used to optimise transportation fleets and identify the optimal locations for waste treatment facilities. This paper provides an overview of the literature, identifying the transport arisings associated with the movement of waste to HWRCs by site users, and from HWRCs to treatment or disposal facilities by service operators. It also discusses the potential impacts on waste transportation from current and impending legislation, and the use of routing and scheduling applications to maximise commercial service vehicle operating efficiency.
Advanced simulation in design
Authors: Weinstock Michael , Stathopoulos Nikolaos
Published: June 2006

Simulations are essential for designing complex material systems, and for analysing their behaviour over extended periods of time. As Michael Weinstock and Nikolaos Stathopoulos explain, working with simulations requires the development of a mathematical model of physical processes, and generative computational design can now inexpensively incorporate the advanced physics of nonlinear behaviour to explore the dynamic changes that structures and materials undergo in response to changing conditions. Copyright © 2006 John Wiley & Sons, Ltd.