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.     

Automatische Wirkstoff bestimmungen in Arzneimittelzubereitungen

Zusammenfassung Es wird eine automatische Lipasebestimmung in Festal^® mit dem AutoAnalyzer^® angegeben. Eine in einem Emulsionsrührer in Gegenwart von Aktivatoren und einem Emulgator hergestellte Triolein/ Wasseremulsion wird mit einem Dragee-Extrakt der zu bestimmenden Probe inkubiert. Das bei der enzymatischen Spaltung unter anderem entstehende Glycerin wird mit Perjodat zu Formaldehyd oxydiert, der sich mit zugegebenem Ammoniak und Acetylaceton in einer Hantzsch-Kondensation zum 3,5-Diacetyl-1,4-dihydrolutidinumsetzt. Das Reaktionsprodukt wird fluorimetrisch ausgemessen. Die relative Standardabweichung der Methode beträgt ±3,5%, die Analysenfrequenz 20 Einzelbestimmungen/h.

---

Automatic determination of active agents in drug preparations2. Determination of lipase in Festal^®

An automatic determination of lipase in Festal^® by aid of the AutoAnalyzer^® is described. A triolein/water emulsion made by aid of a special emulsifier, is incubated with a sample of the drug to be determined. Glycerol, one of the products gained by the enzymic reaction, is oxidized by periodate into formaldehyde; the addition of ammonia and acetylacetone to the formaldehyde produces in a Hantzsch condensation 3,5-diacetyl-1,4-dihydrolutidine, which is measured fluorimetrically. The relative deviation of this method is ±3.5%, the frequency of analysis is 20 determinations/h.

---

---

1. Mitteilung: H. J. Böhme u. H. Dost [2].     

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.     

Incorporation of surface tension to interface energy balance in crystal growth

Effect of surface tension across a growth interface is known as the Gibbs‐Thomson effect, and the associated energy balance is widely referred to as the Stefan condition in the literature, which is derived from thermodynamics. In this article, the interface energy balance that accounts for the effect of surface tension is derived by writing the jump condition for the energy balance on a surface of discontinuity which represents in crystal growth the evolving growth interface (solidification front) between the liquid and solid phases. To the best of our knowledge, the derivation of energy balance by writing jump conditions on a surface of discontinuity (interface) is new. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

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.     

Less Is More: Three‐Coordinate C,N‐Chelated Distannynes and Digermynes

We report here the synthesis of new C,N‐chelated chlorostannylenes and germylenes L³MCl (M=Sn( 1 ), Ge ( 2 )) and L⁴MCl (M=Sn( 3 ), Ge ( 4 )) containing sterically demanding C,N‐chelating ligands L^{3, 4} (L³=[2,4‐di‐tBu‐6‐(Et₂NCH₂)C₆H₂]^?_; L⁴=[2,4‐di‐tBu‐6‐{(C₆H₃‐2′,6′‐iPr₂)N=CH}C₆H₂]^?). Reductions of 1 – 4 yielded three‐coordinate C,N‐chelated distannynes and digermynes [L^{3, 4}M ]₂ for the first time ( 5 : L³, M=Sn, 6 : L³, M=Ge, 7 : L⁴, M=Sn, 8 : L⁴, M=Ge). For comparison, the four‐coordinate distannyne [L⁵Sn]₂ ( 10 ) stabilized by N,C,N‐chelate L⁵ (L⁵=[2,6‐{(C₆H₃‐2′,6′‐Me₂)N?CH}₂C₆H₃]^?) was prepared by the reduction of chlorostannylene L⁵SnCl ( 9 ). Hence, we highlight the role of donor‐driven stabilization of tetrynes. Compounds 1 – 10 were characterized by means of elemental analysis, NMR spectroscopy, and in the case of 1 , 2 , 5 – 7 , and 10 , also by single‐crystal X‐ray diffraction analysis. The bonding situation in either three‐ or four‐coordinate distannynes 5 , 7 , and 10 was evaluated by DFT calculations. DFT calculations were also used to compare the nature of the metal–metal bond in three‐coordinate C,N‐chelating distannyne [L³Sn]₂ ( 5 ) and related digermyme [L³Ge]₂ ( 6 ).     

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.     

From a 2,1-Benzazaarsole to Elusive 1-Arsanaphthalenes in One Step

The 2,1-benzazaarsole ( 1 ) showed a diene-like reactivity towards selected alkynes RC≡CR (R=CO₂Me, C₅F₄N) thus forming 1-arsa-1,4-dihydro-iminonaphthalenes 2 a and 3 a as hardly isolable intermediates, that underwent facile CH→NH proton migration leading to before elusive substituted 1-arsanaphthalenes 2 b and 3 b that could be completely structurally characterized.