Synthesis of optically active 2-ethyl-1,6-dioxaspiro[4.4]nonane (chalcogran), the principal aggregation pheromone of pityogenes chalcographus (l.)1

((2R, 5RS)- and (2S, 5RS)-2-Ethyl-1,6-dioxaspiro[4.4]nonanes (chalcograns) were synthesized in a simple manner by applying the recent technique of dianion chemistry.     

Fully automated micro- and nanoscale one- or two-dimensional high-performance liquid chromatography system for liquid chromatography-mass spectrometry compatible with non-volatile salts for ion exchange chromatography

A one- or two-dimensional high performance liquid chromatography system for electrospray ionization mass spectrometers has been developed that is optimized for ion exchange and reversed phase separations. A unique and simple valve configuration permits the use of a variety of non-volatile salts; ammonium sulfate was used in an example of strong cation exchange separations. The system was designed and evaluated for both micro- and nanoflow chromatography. The peptide detection limit was approximately 100 fmol for micro- and 20 fmol for nanoflow, demonstrating the concentration and mass sensitivity improvements expected with nanoelectrospray ionization. The 1D/2D-HPLC MS system is fully automated for routine peptide analyses, compatible with direct injection of proteolytic digests, and exhibits chromatographic reproducibility and sensitivity. Software permits operator selection of either a 1D or 2D configuration with corresponding system parameters as required for individual samples. The hardware elements and resulting performance are described in this paper.     

Self-assembly patterning of colloidal crystals constructed from opal structure or NaCl structure

We developed a novel self-assembly process to fabricate an orderly array of particle wires constructed from a close-packed colloidal crystal without preparation of patterned templates. A substrate was immersed vertically into a SiO2 colloidal solution, and the liquid surface moved downward upon evaporation of solution. Particles formed a mono-/multiparticle layer, which was cut by the periodic drop-off of solution. The orderly array of particle wires was successfully fabricated, showing the suitability of the self-assembly process for the fabrication of nano-/microstructures constructed from nano-/microparticles or blocks. The mechanism of the assembly process and control of thickness, width, and interval of particle wires were further discussed. Moreover, an array of particle wires constructed not from close-packed face-centered cubic (or hexagonal close packed) structure but from two kinds of particles was realized to fabricate an array of particle wires with NaCl structure by this self-assembly process.     

Organoaluminum–cyclic ether-cyclic imide catalysts for the polymerization of epoxides

A catalyst for the polymerization of epoxides consisting of trialkylaluminums, cyclic ethers, and cyclic imides has been investigated. Various catalyst components were examined to reveal that the combination of triisobutylaluminum, dioxane, and succinimide gives the most active catalyst. The catalytic activity is greatly enhanced with aging in which the change in color from pale yellow to dark red takes place. The polymerization data show that the dioxane provides a pathway for the catalyst components to form an active species. The dioxane-containing catalyst is likely to be different in structure from that of the dioxane-free catalyst. It was shown that the catalyst solution is electrically conductive. A parallel correlation seems to exist between the electrical conductivity and the catalytic activity, suggesting that the catalytic species may be of an ionic character.     

Synergic solvent extraction studies of gadolinium using a combination of the di(2-ethylhexyl)phosphoric acid and three adductants into kerosine/chloroform

The equilibrium extraction behaviour of Gd(III) using a chloroform/kerosine solution containing di(2-ethylhexyl)phosphoric acid (HDEHP), either alone or combined with one of three adductants, 1,10-phenanthroline monohydrate (phen), alpha,alpha'-dipyridyl(2,2'-bipyridine) (bipy) or trioctylphosphine oxide (TOPO) is described. The enhancement of the extraction by addition of such neutral adductants is explained in terms of adduct formation of the metal chelate in the organic phase. Among the three synergistic mixtures, 1,10-phenanthroline is the most promising for the extraction of the last member of light lanthanoids, gadolinium. Gadolinium ions are found to be extracted in the absence of phen, bipy or TOPO; the species was M(HA(2))(3) but M(HA(2))(3))(phen)(2) was found when phen was added and M(HA(2))(3)(bipy), M(HA(2))(3)(bipy)(2) was found when bipy was added and M(HA(2))(3)(TOPO) was found when TOPO was added. The compositions of the extracted species are obtained from the slope analysis method. pH (1 2 ) values were also obtained. The stoichiometry, extraction constants and stability constants of these systems were determined. Synergistic extraction can be carried out at lower pH.     

Synthesis and properties of a poly(diphenylacetylene) containing carbazolyl groups

1-(p-N-Carbazolylphenyl)-2-phenylacetylene (p-CzDPA) was polymerized by TaCl₅–co-catalyst systems (cocatalysts: n-Bu₁Sn, Et₃SiH, and 9BBN) to produce acetone-insoluble polymers in about 60-70% yields. Poly(p-CzDPA) was a yellowish-orange solid, most part of which was soluble in toluene, chloroform, etc., and its weight-average molecular weights were around 4×10⁵. This polymer formed a tough film by solution casting, and was thermally very stable (the onset temperature of weight loss in TGA in air 470°C). The oxygen per-meability coefficient of the polymer at 25°C was lower than two barrers. The present polymer showed photoconductivity and redox activity. © 1995 John Wiley & Sons, Inc.     

Diffusion Mechanisms of Zeolite Catalysts

The diffusion mechanisms within zeolite catalysts, such as resistance to diffusion at pore mouths, configurational diffusion, adsorption-controlled diffusion, influence of co-existing molecules and pore blocking, were overviewed. Two kinds of diffusivities, the intracrystalline diffusivity and the effective diffusivity, were discussed separately to clarify the diffusion mechanism.     

The nature of europium ion in carbonate solution and polarographic determination of micro amounts of europium

The nature of the complex europium carbonate ion in concentrated carbonate solution was studied polarographically. A polarographic method for the determination of micro amounts of europium ion in the presence of diverse ions (and especially lanthanides) was developed.     

A thermal and structural study on Lanthanum Hexacyanocobaltate(III) pentahydrate,La[Co(CN)6]·5H2O. Part III

On dehydration of La[Co(CN)₆]·5H₂O, the color of the complex, changes from white to pale blue at around 230°C. Heating the pale blue specimen, the color changes to deep blue at around 290°C. This deep blue specimen is easily rehydrated to a pink one. As reported previously, in the pale blue specimen, Co³⁺ ions are situated in the center of the D_4h crystal field formed by six CN^- ions. The deep blue specimen is due to the presence of [Co(CN)₄]^2- ions in which Co²⁺ was situated in a T_d coordination field formed by four CN^- ions and the Co-C bond length is 1.67 Ĺ. The pink species corresponded to trans-[Co(CN)₄(H₂O)₂]^2- and the bond lengths of Co-C and Co-O are 1.89 and 1.85 Ĺ, respectively. The Raman spectra of the complex observed at 25°C displays two bands at 2157 and 2176 cm^-1 associated with the vibration of C-N bond, and the band of 2157 cm^-1 was split into two bands, 2150 and 2156 cm^-1, at around 100°C. When the complex was heated to around 230°C, three new bands were observed at 2103, 2116 and 2141 cm-1. The bands of 2103 and 2116 cm^-1 were assigned to the stretching vibration of C=N bonding to Co²⁺. The band of 2141 cm^-1 was assigned to the stretching vibration of the inverted CN^- as follows: Co-C=N-La→Co-N=C-La. The activation energy for the inversion of CN^- was estimated as 67 kJ mol^-1. This revised version was published online in August 2006 with corrections to the Cover Date.