3,3-Dimethoxypropylsulfonyl Group: A new versatile protecting and activating group for amine synthesis

3,3-Dimethoxypropylsulfonyl (Dimps) chloride was prepared and used as a new versatile sulfonating agent for ammonia, primary and secondary amines to afford corresponding Dimps-amides in excellent yields. The resulting N-nonsubstituted and N-monosubstituted Dimps-amides, activated amines, were alkylated satisfactorily under new Mitsunobu conditions. The Dimps group was removed by treatment in aqueous solution under acidic followed by basic conditions. Furthermore, epilachnene, the defensive droplets from the Mexican bean beetle, Epilachna varivestis, was synthesized utilizing this Dimps methodology in short steps.     

Nanomechanical properties of reversed surfactant bilayers formed in micrometre-sized holes

Nanomechanical properties of free-standing reversed surfactant bilayers, dried foam films (DFFs), were examined via AFM by fitting local force-indentation curves with a Hertzian model. The Young's moduli of four kinds of bilayers were in a range of 10-30 MPa.     

New layered rare-earth hydroxides with anion-exchange properties

We report the synthesis of a new series of layered hydroxides based on rare-earth elements with a composition of RE(OH)2.5Cl(0.5).0.8 H2O (RE: Eu, Tb, etc.) through the homogeneous precipitation of RECl3.x H2O with hexamethylenetetramine (HMT). Rietveld analysis combined with direct methods revealed an orthorhombic layered structure comprising a positively charged layer of [RE(OH)2.5-(H2O)0.8]0.5+ and interlayer Cl- ions. The Cl- ions were readily exchangeable for various anions (NO3-, SO4(2-), dodecylsulfonate, etc.) at ambient temperature. Photoluminescence studies showed that the compounds display typical RE3+ emission. With rare-earth-based host layers and tunable interlayer guests, the new compounds may be of interest for optoelectronic, magnetic, catalytic, and biomedical materials.     

Structural disorder and diffusional pathway of oxide ions in a doped Pr2NiO4-based mixed conductor

MEM nuclear density analysis from neutron diffraction data measured in situ at 1015.6 degrees C has indicated the two-dimensional network of curved O2-O3-O2 oxide-ion diffusion paths on the (Pr,La)-O layer in a K2NiF4-type structured oxide-ionic and electronic mixed conductor (Pr0.9La0.1)2(Ni0.74Cu0.21Ga0.05)O4+delta.     

General method for ultrathin free-standing films of nanofibrous composite materials

A simple and general method for the preparation of ultrathin, large-area, free-standing films of nanofibrous composite materials was developed. First, positively charged cadmium hydroxide nanostrands of 1.9 nm in diameter and micrometers in length were prepared by mixing dilute aqueous solutions of cadmium chloride and aminoethanol. Negatively charged dye molecules, proteins, nanoparticles, and water-soluble fullerene or carbon nanotubes were mixed with the nanostrands to give a well-dispersed solution of the corresponding nanofibrous composites. After filtration of the dispersions with a polycarbonate membrane filter, uniform films with a thickness of a few tens to hundreds of nanometers and a diameter of a few centimeters were obtained. The films were readily peeled off from the membrane filter by immersion in ethanol. The resultant free-standing films could be further transferred to other substrates, such as quartz plate, gold electrode, and porous alumina membrane, and were characterized by scanning and transmission electron microscopies. We provide herein various nanofibrous free-standing films with optical, biological, metallic, and magnetic properties.     

A Simple Derivation of Josephson's Formulae in Superconductivity

A simple and general derivation of Josephson's formulae for the tunneling currents is presented on the basis of Sewell's general formulation of superconductivity in relation to off-diagonal long-range order (ODLRO).     

Alternative molecularly imprinted polymeric membranes from a tetrapeptide residue consisting of D- or L-amino acids

Alternative molecularly imprinted polymeric membranes were prepared from a polystyrene resin bearing tetrapeptides consisting of D -amino acids or L-amino acids. The membrane prepared from a DLDE derivative (H-Asp(OcHex)-Leu-Asp(OcHex)-Glu(OBzl) CH₂ ) consisting of D -amino acids and imprinted by Boc-D -Trp recognizes the D-isomer in preference to the corresponding L -isomer and vice versa. The amino acid preferentially adsorbed by the membrane was selectively permeated by applying electrodialysis.     

Growth and properties of air-processed GdBa2Cu3O7−δ superconductors with fined Gd2BaCuO5 and Gd2Ba4CuFeOy additions

We have succeeded in synthesizing a powder form of Gd₂Ba₄CuFeO_y (Gd2411) in air. GdBa₂Cu₃O_7−δ (Gd123)/Gd₂BaCuO₅ (Gd211) precursor powders added with different amounts of Gd₂Ba₄CuFeO_y (x = 0, 0.002, 0.004, 0.02) in molar ratio to Gd123 have been fabricated successfully into the form of large, single grains by the top seeded melt growth (TSMG) process. The relation between the additions amounts of Gd2411/Gd211 and critical current density (J_C) was analyzed. We found Gd2411 particles stably exist in the Gd123 matrix without degradation of superconducting properties owing to the existence of the Fe magnetic ion. The trapped field was observed to increase significantly compared with the bulk without Gd2411 additions.     

Adaptive exponential approximation of optical density ratio using third-order regression equations for depth profiling of a blood inclusion in a skin tissue model

We propose the use of the third-order multiple regression equations in approximating an optical density ratio with an adaptive exponential function for measuring depth and thickness of a blood inclusion embedded in a skin tissue model. To ensure accuracy of the exponential approximation, we investigated numerically various relations of optical density ratios versus depth and thickness, on the basis of Monte Carlo simulations for a layered skin tissue model. The third-order multiple regression analysis based on the relations above was used to derive regression equations for the determination of depth and thickness. Experiments with skin tissue phantoms were used to assess this approach.     

Synthesis, cyclic voltammetry, and UV–Vis studies of ferrocene-dithiafulvalenes as anticipated electron-donor materials

Abstract  

New ferrocenyl ketones were obtained as precursors of novel π-conjugated ferrocene-dithiafulvalene (Fc-DTF) and π-extended-ferrocenedithia-fulvalenes (π-exFc-DTF) as electron-donor conducting materials from ferrocene by a direct aroylation process using the Friedel–Crafts reaction. Novel Fc-DTF conjugates were synthesized using the Wittig–Horner reaction and their structures were determined. The redox behavior of the ferrocenyl carbonyl compounds Fc-DTF and Fc-π-exDTF was investigated in comparison to the parent ferrocene by means of cyclic voltammetry. A one-electron redox behavior was observed for carbonylferrocenes as one wave potential, while a two-electron process was observed as two oxidation waves for the conjugates. Introduction of electron-withdrawing groups led to increasing E _pa values and decreasing ΔE _p values. The UV–Vis spectra of some compounds were studied in comparison with ferrocene. The absorption spectra showed a red-shift with a slight increase in the absorption intensities.