Materials Literature
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Vernetzte Poren: Bei der Templatsynthese von Metalloxiden mit nichtionischen Alkyl-PEO-Tensiden bilden sich mesoporöse Strukturen (siehe Bild). Ihre einheitlichen Makroporen verlaufen parallel zueinander senkrecht zur Oberfläche und verjüngen sich im Inneren des Festkörpers trichterförmig. Die einzelnen Poren sind dur…
Abstract Various natural and modified polysaccharides ( i.e. arabic gum, tragacanth gum, xanthan gum, sodium alginate, chitosan, sodium carboxymethyl cellulose, hydroxyethyl cellulose, methyl cellulose) were modified using ceric‐initiated graft polymerization of acrylonitrile under inert atmosphere. Grafting was confi…
An experimental study of the high-temperature polymerization of styrene in a CSTR, investigating the effect of reaction temperature (260−343 °C), and residence time (5−90 min) on monomer conversion and average molecular weight and distribution is reported. A kinetic analysis of these experimental data demonstrates tha…
Abstract An interesting ferromagnetic linear trinuclear copper( II ) compound containing an in‐situ synthesised functional ligand has been rationally obtained and crystallographically characterised, confirming a new route to magnetic polynuclear clusters. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, German…
We report on the introduction of small organic hydrophilic molecules (fluorescein, rhodamine B, and two coumarin-based dyes) in multilayers of strong polyelectrolytes, studied by X-ray reflectometry, UV/visible spectroscopy, and fluorescence measurements. Very low diffusion coefficients (about 10 - 17 cm 2 ·s - 1 ) we…
We report the results of atomic force microscopy (AFM) based nanoscale probing of thermal and nanomechanical properties of relatively thick (50−90 nm) polymer brush layers from poly(styrene- co -2,3,4,5,6-pentafluorostyrene) (PSF) and polymethylacrylate (PMA). These layers, with a high density of grafting, are synthes…
Double K-shell photoionization of Ne at 5000 eV was observed by recording the KK-KLL Auger-electron hypersatellite spectrum. The measured Auger spectrum is compared with the results of multiconfiguration Dirac-Fock calculations. Shake calculations are used to identify likely multivacancy states produced by photoexcita…
Isothermal dielectric relaxation measurements were carried out on xylitol and threitol. These, together with existing data on sorbitol and glycerol, enabled us to identify the general features in the frequency dispersion and the changes when increasing the number of carbon atoms in the molecule in these polyalcohols.…
Abstract Metal‐driven self‐assembly has emerged as a viable alternative to covalent synthesis in the construction of large and sophisticated multi‐porphyrin architectures, whose complexity and function begin to approach the properties of naturally occurring systems. The design and preparation of robust and shape‐persi…
Figures of eight correlate with corrolates: The surprising formation of the spirodicorrole dinickel complex 1, the first spirodiporphyrin as a metal complex, is the result of the varied chemistry of the “figure-eight” cyclooctapyrrole octaphyrin-(1.1.1.0.1.1.1.0). The conversion of the cyclooctapyrrole into 1 is broug…
Abstract Oxygen‐excessive LaMnO 3+ y samples with 0.02 ⩽ y ⩽ 0.26 have been prepared by thermal decomposition in air at 450 °C of a precursor obtained from an aqueous solution of lanthanum nitrate and manganese acetate (atomic ratio La/Mn = 1). The obtained solid is annealed at different temperatures from 700 to 1000…
Abstract Polylactide (PLA)‐grafted dextran was synthesized with a trimethylsilyl protection method to produce novel biodegradable, biomedical materials. PLA‐grafted dextrans with various lengths and numbers of graft chains were synthesized. The properties of solution‐cast films prepared from PLA‐grafted dextrans were…
This paper discusses the synthesis of linear polyolefin elastomers containing divinylbenzene (DVB) units, including poly(ethylene- ter -propylene- ter -divinylbenzene) (EP-DVB) and poly(ethylene- ter -1-octene- ter -divinylbenzene) (EO-VDB). Several metallocene catalysts were evaluated to identify a system that can ca…
[reaction: see text] Polymer-supported bisBINOL ligands were successfully utilized for the immobilization of multicomponent asymmetric catalysts. The polymer-supported Al-Li-bis(binaphthoxide) (ALB) catalyst was more effective than the dendrimer-supported ALB in the Michael reaction of 2-cyclohexen-1-one with dibenzyl…
Abstract An ion‐pair complex [FBzPyNH 2 ][Ni(mnt) 2 ] {[FBzPyNH 2 ] + = [1‐(4′‐fluorobenzyl)‐4‐amino]pyridinium and mnt 2− = maleonitriledithiolate} has been obtained by I 2 oxidation of the corresponding dianion complex. It forms a wellsegregated stacking column structure in the solid state, and exhibits antiferromag…
Pyridoxine 5'-phosphate oxidase catalyzes the terminal step in the synthesis of pyridoxal 5'-phosphate. The cDNA for the human enzyme has been cloned and expressed in Escherichia coli. The purified human enzyme is a homodimer that exhibits a low catalytic rate constant of approximately 0.2 sec(-1) and K(m) values in t…
First principles density functional theory is used to study the compositional dependence of the structural, elastic, electronic, and bonding properties of newly prepared Sn x Ge 1 - x alloys and compounds. The calculated variation of lattice constant a ( x ) with composition for tin content (% Sn, x < 0.20) exhibits a…
Making 13 from 55: Au55 nanoclusters that interact with the major groove of B-DNA (see energy-minimized structure), are broken down into Au13 clusters by the transformation of B-DNA into A-DNA, during which the major groove shrinks dramatically. This transformation, which results in the formation of Au13 wires, is ini…
Breaking the law: Whereas antiferromagnetic interactions in crystalline carboxylates of lanthanides are often observed, ferromagnetism is unknown. The first example of a ferromagnetic interaction is observed for a crystalline sample of the gadolinium compound [{Gd(OAc)3(H2O)2}2]⋅4 H2O (see picture Gd: gray, O: red).
A self-inducing template-growth approach to the production of nanofibers of 1,3-diphenyl-2-pyrazoline (DP) in the presence of cetyltrimethylammonium bromide (CTAB) in an aqueous phase is discussed (see picture). Not only the surfactant CTAB molecules assume the role of surface-active colloidal stabilizers; but also th…