Materials Literature
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Macromolecular crystallization is a complex process, involving a system that typically has five or more components (macromolecule, water, buffer + counterion, and precipitant). Whereas small molecules have only a few contacts in the crystal lattice, macromolecules generally have 10's or even 100's of contacts between…
A novel molecular based proton-electron mixed conductor, (H3BBIM(+))(TCNQ)(Cl(-))(0.5)(H(2)O) (1), where H3BBIM(+) is 2-(2-1H-benzimidazolyl)-1H-benzimidazolium and TCNQ is 7,7,8,8-tetracyano-p-quinodimethane, was synthesized. The salt exhibited peculiar phase transitions as a result of proton-electron coupling phenom…
Single ${\mathrm{Ar}}_{n}$ or $({\mathrm{CO}}_{2}{)}_{n}$ $(n\ensuremath{\simeq}960)$ cluster impacts on a diamond (111) surface are studied by large-scale molecular dynamics simulations in order to investigate highly energetic cluster-surface interactions. For a cluster impact energy ${E}_{a}$ of 100 keV, a hemispher…
The linear correlation between the increase of fluorescence and the extent of photolysis upon flash photolysis of bis(carboxymethoxy)coumarinylmethyl-caged cAMP (1, R=H, R′=NH2) and cGMP (2, R= NH2, R′=OH) allows the visualization and quantification of the release process of the cyclic nucleotides within cells.
Turning off the light. A fluorescence quencher based on azulene was synthesized which absorbs light in the range of 650 to 800 nm. Since protease sensing was possible with the derivative shown (Alexa Fluor 680 is the fluorochrome), applications in vivo for imaging molecular targets can be expected.
Substitutional solid solutions of metal hexacyanometalates in which low-spin iron(III) and cobalt(III) ions populate the carbon-coordinated sites were synthesized and studied by powder diffraction including Rietveld refinement, cyclic voltammetry of immobilized microparticles, diffuse reflection vis-spectrometry, and…
Responsive sensing clusters: By linking {(Mo)Mo5} type building units with different spacers, spherical clusters (nanosponges) having 20 different nanosized and tunable MonOm pores/macrocycles of the type and quality of the classical crown ethers of supramolecular chemistry are formed (see picture of an {Mo9O9}-type h…
The thermal conductivity $\ensuremath{\kappa}$ of the quasi-two-dimensional (Q2D) organic superconductor $\ensuremath{\lambda}\ensuremath{-}(\mathrm{BETS}{)}_{2}{\mathrm{GaCl}}_{4}$ [BETS = bis(ethylenedithio)tetraselenfulvalene] was studied in the magnetic field H applied parallel to the Q2D plane. The phase diagram…
An eosin molecule encapsulated into the dendrimer shown in the picture collects electronic energy from all 64 chromophoric units of the dendrimer, which comprises three different types of chromophore. Efficient intramolecular (within the dendrimer) and intermolecular (dendrimer-host→eosin-guest) energy-transfer proces…
By assembling azulene units (fused pentagon-heptagon pairs) and hexagons, and applying specific wrapping rules to these structures resembling some recently-proposed Haeckelite structures [Terrones et al., Phys. Rev. Lett. 84, 1716 (2000)], a large variety of toroidal, coiled, screwlike, and double-helix structures can…
The polarized Raman spectra of ${\mathrm{CaCu}}_{3}{\mathrm{Ti}}_{4}{\mathrm{O}}_{12}$ (CCTO) single crystals were studied between 10 and 600 K. Five of the eight ${(2A}_{g}{+2E}_{g}{+4F}_{g})$ Raman active modes expected for the $\mathrm{Im}3\ifmmode\bar\else\textasciimacron\fi{}$ structure were observed at $292{(F}_…
We calculate the contribution of the Neel surface anisotropy to the effective anisotropy of magnetic nanoparticles of spherical shape cut out of a simple cubic lattice. The effective anisotropy arises because deviations of atomic magnetizations from collinearity and thus the energy depends on the orientation of the gl…
Chrysotile asbestos is formed by densely packed bundles of multiwall hollow nanotubes. Each wall in the nanotubes is a cylindrically wrapped layer of Mg(3)Si(2)O(5)(OH)(4). We show by experiment and theory that the infrared spectra of chrysotile present multiple ionic-plasmon resonances in the Si-O stretching bands. T…
The phenomenally large enhancement in conductivity observed when Li-doped MgO crystals are oxidized at elevated temperatures was investigated by dc and ac electrical measurements in the temperature interval 250--673 K. The concentration of $[\mathrm{Li}{]}^{0}$ centers (substitutional ${\mathrm{Li}}^{+}$ ions each wit…
In-plane anisotropy of the resistivity and thermopower was measured for single crystal Bi2-xPbxSr2Co2Oy. There is large in-plane anisotropy, which is attributed to the anisotropic pseudogap formation due to the different crystal symmetry between the square Bi2Sr2O4 layer and the triangular CuO2 layer. The magnitude of…
We use synchrotron x-ray and precision electron diffraction techniques to determine accurately the structure factors of selected reflections that are sensitive to the valence electron distribution in the superconductor MgB2. These values deviate significantly from calculated structure factors using the scattering fact…
Controlling growth: Large arrays of oriented conducting polymer nanowires were prepared by controlled nucleation and growth during a stepwise electrochemical deposition process, without the use of porous membrane supports (see scheme and electron micrographs).
Es bien sabido que las interacciones de canje inducidas entre materiales ferromagneticos (FM) y antiferromagneticos (AFM) cuando son enfriados desde una temperatura superior a la temperatura de Neel, TN, del AFM, hacen aumentar la coercividad, HC, del componente FM. Nosotros hemos analizado los efectos de hacer una mo…
Abstract The degradation of polyfuran in a wet acetonitrile solution and in an aqueous solution has been investigated with a cyclic voltammetry technique, along with Fourier transform infrared and Fourier transform Raman spectroscopy techniques. Infrared spectroscopy shows that the main defects that exist in polyfuran…
Luminescence is reported from the ${}^{2}{\mathrm{I}}_{11/2}$ level of ${\mathrm{Er}}^{3+},$ in the cubic elpasolite lattices ${\mathrm{Cs}}_{2}{\mathrm{NaErCl}}_{6}$ and ${\mathrm{Cs}}_{2}{\mathrm{NaYCl}}_{6}.$ Altogether, with the use of ultraviolet laser excitation, 11 transitions from ${}^{2}{\mathrm{I}}_{11/2}$ $…