Synthesis of new proton-ionizable and neutral macrocyclic,macrobicyclic and macrotricyclic crown compounds containing dibenzo-16-crown-5 units

Fifteen new macrocyclic, macrobicyclic and macrotricyclic crown ether compounds with sym-dibenzo-16-crown-5 units have been prepared. The series includes macrocyclic polyether and bis(crown ether) compounds with proton-ionizable carboxylic or phosphonic acid monoethyl ester groups and bis(crown ether) and macrotricyclic polyether compounds with two sym-dibenzo-16-crown-5 units linked by amide, diamide, or diester functions.     

Nanostructured polyamic acid membranes as novel electrode materials

This paper describes a new approach for the preparation of polyamic acid (PAA) composites containing Ag and Au nanoparticles. The composite film of PAA and metal particles were obtained upon electrodeposition of a PAA solution containing gold or silver salts with subsequent thermal treatment, while imidization to polyimide is prevented. The structural characterization of the films is provided by 1H NMR and Fourier transform infrared spectroscopy (FTIR), while the presence of metallic nanoparticles within the polymeric matrix was confirmed by scanning electron microscopy (SEM), cyclic voltammetry (CV), energy-dispersive X-ray analysis (EDX), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). This approach utilizes the unique reactivity of PAA by preventing the cyclization of the reactive soluble intermediate into polyimides at low temperature to design polymer-assisted nanostructured materials. The ability to prevent the cyclization process should enable the design of a new class of electrode materials by use of thermal reduction and/or electrodeposition.     

Highly selective Ba2+ separations with acyclic, lipophilic di-[N-(X)sulfonyl carbamoyl] polyethers

New lipophilic acyclic polyethers with two N-(X)sulfonyl carbamoyl groups of "tunable" acidity exhibit remarkable selectivity for Ba2+ over other alkaline earth metal ions in competitive solvent extraction and transport across polymer inclusion membranes.     

Monitoring the specific adsorption of proteins using the electrochemical quartz crystal microbalance electrodes

This work describes the results of a mechanistic investigation of antibody-antigen binding using electrochemical quartz crystal microbalance (EQCM). The aim was to verify the contribution of electrolytes to conducting polypyrrole electrodes that have been modified with proteins. The behavior of an EQCM film containing various counterions was studied (chloride, dodecylsulphate and proteins) and mass changes recorded in a series of anions, cations and proteins. Results obtained indicate that the interaction of different proteins at quartz crystal electrode surface is dependent on the applied potential, the nature of the cations and anions, and the specificity of the immobilized antibody. The resonant frequency of the anti-HSA-coated quartz abruptly decreased upon contact with the antigen and this stabilized within 5 min in the concentration range between 1 and 100 ppm. The injection of other proteins such as bovine serum albumin and chymotrypsin, yielded responses that were significantly lower in magnitude than those obtained for the corresponding HSA.     

Lariat ether alcohols based on dibenzo‐16‐crown‐5

Synthetic routes to forty‐four dibenzocrown ether alcohols are reported. The new crown ether com pounds are based on a sym‐dibenzo‐16‐crown‐5 platform. Most have a hydroxy group and an alkyl, aryl, aralkyl, alkenyl, alkynyl, or perfluoroalkyl group on the central carbon of the three‐carbon bridge. Others have substituted benzene rings and either a hydroxy or ‐O(CH₂)_nOH group attached to the central carbon of the three‐carbon bridge.     

Structural and electronic properties of InNxP1-x alloy in full range (0 ≤ x ≤1)

We have performed first-principles method to investigate structural and electronic properties of InN_xP_1?x ternary semiconductor alloy in full range (0 ≤ x ≤ 1) using density functional theory. We have used modified Becke–Johnson potential to obtain accurate band gap results. From the electronic band structure calculation we have found that InN_xP_1?x become metal between 47 and 80% of nitrogen concentration. Additional to our band gap calculations, we have also used the band anticrossing model. The band anticrossing model supplies a simple, analytical expression to calculate the physical properties, such as the electronic and optical properties, of III-N_xV_1?x alloys. The knowledge of the electron density of states is required to understand and clarify some properties of materials such as the band structures, bonding character and dielectric function. In order to have a deeper understanding of these properties of the studied materials, the total and partial density of states has been calculated. Finally, we have calculated the total bowing parameter b of studied alloys, together with three contributions b_VD, b_CE, and b_SR due to volume deformation, different atomic electron negativities and structural relaxation, respectively.     

A Geometric Theory of Nonlinear Morphoelastic Shells

Many thin three-dimensional elastic bodies can be reduced to elastic shells: two-dimensional elastic bodies whose reference shape is not necessarily flat. More generally, morphoelastic shells are elastic shells that can remodel and grow in time. These idealized objects are suitable models for many physical, engineering, and biological systems. Here, we formulate a general geometric theory of nonlinear morphoelastic shells that describes both the evolution of the body shape, viewed as an orientable surface, as well as its intrinsic material properties such as its reference curvatures. In this geometric theory, bulk growth is modeled using an evolving referential configuration for the shell, the so-called material manifold. Geometric quantities attached to the surface, such as the first and second fundamental forms, are obtained from the metric of the three-dimensional body and its evolution. The governing dynamical equations for the body are obtained from variational consideration by assuming that both fundamental forms on the material manifold are dynamical variables in a Lagrangian field theory. In the case where growth can be modeled by a Rayleigh potential, we also obtain the governing equations for growth in the form of kinetic equations coupling the evolution of the first and the second fundamental forms with the state of stress of the shell. We apply these ideas to obtain stress-free growth fields of a planar sheet, the time evolution of a morphoelastic circular cylindrical shell subject to time-dependent internal pressure, and the residual stress of a morphoelastic planar circular shell.     

1,1‐Ethylboration of alkyn‐1‐yl‐chloro(methyl)silanes: alkenes with chloro(methyl)silyl and diethylboryl groups in cis positions

The 1,1‐ethylboration of alkyn‐1‐yl‐chloro(methyl)silanes, Me₂Si(Cl)? C?C? R ( 1 ) and Me(H)Si(Cl)? C?C? R ( 2 ) [R = Bu ( 2a ), CH₂NMe₂ ( 2b )] requires harsh reaction conditions (up to 20 days in boiling triethylborane), and leads to alkenes in which the boryl and silyl groups occupy cis ((E)‐isomers: 3a , 3b , 5a , 5b ) or trans positions ((Z)‐isomers in smaller quantities: 4b and 6b ). The alkenes are destabilized in the presence of SiH(Cl) and CH₂NMe₂ units ( 5b , 6b ). NMR data indicate hyper‐coordinated silicon by intramolecular N? Si coordination in 3b and 5b , by which, at the same time, weak Si? Cl? B bridges are favoured. Copyright © 2005 John Wiley & Sons, Ltd.