Materials Literature
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UV irradiation of ultrathin ${\mathrm{SiO}}_{2}$ on Si can lead to injection of both holes and electrons into the oxide. 4.9-eV photons lead to electron injection while 6.7-eV photons open up the hole injection channel. The holes and electrons can trap, generating electric fields of opposite signs. Second harmonic gen…
We have measured the infrared reflectivity spectra of ${\mathrm{La}}_{1\ensuremath{-}y}[\mathrm{Sr}(\mathrm{Ba}){]}_{y}{\mathrm{Mn}}_{1\ensuremath{-}x}[\mathrm{Cu}(\mathrm{Zn},\mathrm{Sc}){]}_{x}{\mathrm{O}}_{3}$ $(0<y<~0.3,0<~x<~0.10)$ manganites, in a wide frequency $(100--4000{\mathrm{cm}}^{\ensuremath{…
To learn the structural basis for the unusually tight binding of 8-oxo-nucleotides to the MutT pyrophosphohydrolase of Escherichia coli (129 residues), the solution structure of the MutT-Mg(2+)-8-oxo-dGMP product complex (K(D) = 52 nM) was determined by standard 3-D heteronuclear NMR methods. Using 1746 NOEs (13.5 NOE…
Let's twist again: While the photoisomerization of stilbene analogues in fluid solution occurs by a one-bond-flip mechanism and involves only configurational changes, in a solid solution (glass) a Hula-twist mechanism operates and results in conformational as well as configurational changes (see scheme).
We present the results of an x-ray magnetic circular dichroism (XMCD) investigation of the molecular superparamagnet Mn12-ac. Thanks to an approach based on chemical synthesis of model compounds, the contributions of Mn(III) and Mn(IV) ions to the absorption spectrum and the dichroic signal of Mn12-ac have been separa…
Hybrid core–corona nanoassemblies (shown schematically in the picture, middle) can be used as supramolecular precursors for metal hydroxide colloids (right) with long-term stability. Anionic–neutral hydrophilic diblock copolymers allow metal hydrolysis and condensation reactions to occur in suspension. Particle size a…
Abstract Novel diols containing imide groups were prepared via condensation of aromatic dianhydrides with 5‐amino‐1‐naphthol. The diimide–dinaphthols prepared were characterized by conventional methods and used to synthesize new poly(urethane–imide)s (PUIs). All the polymers were characterized and their physical prope…
Hysteresis phenomena are investigated around the temperature-induced neutral-ionic (N-I) phase transition in the prototype compound tetrathiafulvalene-p chloranil (TFF-CA). A multistep transition is evidenced by neutron scattering, with plateau evolution of Bragg peaks characteristic of symmetry breaking, as well as b…
Abstract A synthetic pathway to functionalized six‐membered dilactones structurally analogous to lactide is described. Through the use of orthogonal protecting groups, the synthesis of functionalized dilactones was performed in a straightforward way by cyanuric chloride‐mediated cyclization of the corresponding linear…
The current picture: Electrochromic and uniform films of different conducting polymers on mirror-polished platinum electrodes were electrochemically reduced and compacted to show the formation and growth of colored nuclei under potentiostatic oxidation (see photographs of films). By interruption of the nucleus growth,…
The propagation and refraction of a cylindrical wave created by a line current through a slab of backward-wave medium, also called left-handed medium, is numerically studied with a finite-difference time-domain method. The slab is assumed to be uniaxially anisotropic. Several sets of constitutive parameters are consid…
It has recently been found that Pluronics (block copolymers of ethylene oxide, EO, and propylene oxide, PO) favor the permeability and accumulation of anthracycline antibiotics, for example doxorubicin (Dox), in tumor cells. In an effort to understand these results, the interaction of EO(2)/PO(32)/EO(2) (Pluronic L61)…
The electrical stability of a novel polypyrrole (PPy)/poly(D,L-lactide) (PDLLA) composite was studied in vitro and compared with that of PPy-coated polyester fabrics. Specimens were incubated in Ringer's solution at 37 degrees C for up to 8 weeks with or without the circulation of DC current under a constant 100 mV vo…
It's all in the casting: The pore sizes of nano-structured light-emitting films cast from linear and star-shaped macromolecular architectures can be engineered from the nano- to microrange by simply manipulating the casting conditions. The confocal microscopy image shows highly fluorescent organized porous materials w…
A full-profile refinement of the layered antiferromagnetic ${\mathrm{FeI}}_{2}$ crystallographic structures at pressures up to 70 GPa were performed combined with ab initio calculations to particularly elucidate the structural aspects of the recently observed pressure-induced quenching of the orbital term of the ${\ma…
A novel colloidal system composed of two kinds of inorganic oxide nanosheets dispersed in water was prepared by mixing exfoliated layered niobate K 4 Nb 6 O 17 and montmorillonite clay. According to the observation of the colloids under crossed polarizers, the obtained niobate−clay colloids were liquid crystalline wit…
The synthesis and characterization of phenylethynyl (PE) end-capped polyimides derived from 4,4‘-(2,2,2-trifluoro-1-phenylethylidene) diphthalic anhydride (3FDA), 4,4‘-(hexafluoroisopropylidene) diphthalic anhydride (6FDA), and 3,3‘,4,4‘-biphenylene dianhydride (s-BPDA) are described in this paper, with particular emp…
A cyanide-bridged molecular square of [Ru(II) (2)Fe(II) (2)(mu-CN)(4)(bpy)(8)](PF(6))(4).CHCl(3).H(2)O, abbreviated as [Ru(II) (2)Fe(II) (2)](PF(6))(4), has been synthesised and electrochemically generated mixed-valence states have been studied by spectroelectrochemical methods. The complex cation of [Ru(II) (2)Fe(II)…
Abstract Poröse Materialien und Materialien mit großer Oberfläche sind in vielen wissenschaftlichen Bereichen von Interesse. Templatverfahren können genutzt werden, um solche Materialien unter Steuerung ihrer Struktur‐ und Textureigenschaften zu synthetisieren, wobei molekulare oder supramolekulare Einheiten als Templ…
A novel organic-inorganic hybrid thermotropic liquid crystal (LC) is developed by the hybridization of an organic amine with a mesogenic core and an acicular anisotropic TiO2 particle through the adsorption of the amino group to the surfaces of the TiO2. The hybrid LC shows nematic phases in wide ranges of temperature…