Search results for " Alloys"
showing 10 items of 1469 documents
Mixed polymeric monolayers and Langmuir-Blodgett multilayers with functional low molecular weight guest compounds
2008
Abstract Mixed monolayers and Langmuir-Blodgett multilayers of functional low molecular weight guest compounds, especially nonlinear optical (NLO) dyes, within the matrix of an amphotropic spacer polymer have been prepared. The polymer matrix enabled the transfer of guest compounds not capable of self-organizing at the air-water interface by themselves. The structure of the LB multilayers and the transfer process were studied by small angle X-ray scattering and UV-visible spectroscopy. Good NLO coefficients were found in the mixed films.
Supramolecular isomerism in spin crossover networks with aurophilic interactions
2004
Assembly of FeII, 3-cyanopyridine and [Au(CN)2]– affords, in one-pot reaction, three coordination polymers that represent a genuine example of supramolecular isomerism with strong influence in the spin crossover regime of the FeII ions. Real Cabezos, Jose Antonio, Jose.A.Real@uv.es
Efficient photovoltaic and electroluminescent perovskite devices.
2015
Planar diode structures employing hybrid organic–inorganic methylammonium lead iodide perovskites lead to multifunctional devices exhibiting both a high photovoltaic efficiency and good electroluminescence. The electroluminescence strongly improves at higher current density applied using a pulsed driving method.
Thermo- and light responsive micellation of azobenzene containing block copolymers
2010
In this communication, the synthesis and characterization of thermo- and light responsive block copolymers is reported. PEO-b-PNIPAM polymers with azobenzene moieties were prepared and analyzed by turbidimetry, fluorescence, NMR and DLS measurements. A temperature controlled reversible formation as well as a light induced disruption and reformation of micellar structures in water was found.
Superexchange pathways in oxovanadium(IV) phosphates
1992
Abstract Oxovanadium(IV) phosphates show a diversity of magnetic behaviours that cannot be deduced from their respective structural features only. In part, this is due to the involvement of phosphate bridges in the spin transfer between V(IV) centres, and 31P solid state nuclear magnetic resonance becomes a key tool in determining the exchange mechanisms. The magnetic properties of a wide set of vanadium(IV) containing derivatives can be explained by realizing that a good overlap of the magnetic orbits may be achieved through paths involving phosphorus d orbitals.
P-chirogenic organocatalysts: application to the aza-Morita–Baylis–Hillman (aza-MBH) reaction of ketimines
2013
The P-chirogenic organocatalysts were found to promote the enantioselective aza-Morita-Baylis-Hillman reaction of ketimines derived from acyclic α-keto esters. In the P-chirogenic organocatalyzed aza-MBH reactions, α,α-disubstituted α-amino acid derivatives were obtained in high yields with high enantioselectivities (up to 97% ee).
Oxamato-based coordination polymers: recent advances in multifunctional magnetic materials
2014
The design and synthesis of novel examples of multifunctional magnetic materials based on the so-called coordination polymers (CPs) have become very attractive for chemists and physicists due to their potential applications in nanoscience and nanotechnology. However, their preparation is still an experimental challenge, which requires a deep knowledge of coordination chemistry and large skills in organic chemistry. The recent advances in this field using a molecular-programmed approach based on rational self-assembly methods which fully exploit the versatility of the coordination chemistry of the barely explored and evergreen family of N-substituted aromatic oligo(oxamato) ligands are prese…
1,3-Dimethylimidazolium-2-carboxylate: the unexpected synthesis of an ionic liquid precursor and carbene-CO2 adductElectronic supplementary informati…
2002
1,3-Dimethylimidazolium-2-carboxylate is formed in good yield, rather than the anticipated organic salt, 1,3-dimethylimidazolium methyl carbonate, as the reaction product resulting from both N-alkylation and C-carboxylation of 1-methylimidazole with dimethyl carbonate; the crystal structure of the zwitterion exhibits π-stacked rings and two-dimensional sheets constructed by hydrogen-bonds from imidazolium-ring hydrogens to the carboxylate group.
Polymeric gegenions induced variability and mobility of amphiphilic supramolecular structures on solid substrates
1992
Abstract The micromorphological variations of amphiphilic L -glutamate derivatives at air-substrate interfaces due to an adjacent mobile polymer matrix have been investigated via fluorescence microscopy. Adjusted monolayers of the L -glutamate derivatives have been transferred by LB technique out of different aggregation states onto various substrates. The substrates have been prepared by successive polymer preadsorption to the solid support. The influence of the adjacent polymer layers on the domain morphology as a function of water content and temperature has been examined intensively. Moreover, reversible domain changes induced by temperature variation of the transferred films have been …
Biosilica-based immobilization strategy for label-free OWLS sensors
2013
Abstract In the last years, a new group of enzymes, so-called silicateins, have been identified and characterized, which form the axial filaments of the spicules of the siliceous sponges, consisting of amorphous silica. Silicateins are able to catalyze the polycondensation and deposition of silica at mild conditions (low temperature and physiological pH). By means of these enzymes it is possible for the first time to produce silica nanostructures biocatalytically, which opens new ways for construction of biosensors. The cDNAs encoding the responsible enzymes have been isolated and the proteins can be produced in a recombinant way. Here we demonstrate the silicatein-mediated biosilica format…