Materials Literature
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The first application of variable-temperature 27 Al MAS NMR spectroscopy to the satellite transitions in the characterization of a structural phase transition is presented by an investigation of Friedels salt (Ca 2 Al(OH) 6 Cl·2H 2 O) over the temperature range from −121 to 109 °C. Accurate values for the 27 Al quadru…
We present a theoretical framework for the viscosity of bimodal and polydisperse colloidal suspensions. For colloidal dispersions both interparticle forces between pairs of particles and many-particle effects such as depletion forces can have a significant effect on rheology. As hydrodynamic interactions are also impo…
A 3 wt % Mo zeolite-supported oxidic precursor prepared from ammonium heptamolybdate by incipient wetness impregnation was studied using Raman and 27 Al NMR spectroscopies, at the various steps of its preparation. The formation of an Anderson type aluminomolybdate anion, which was preserved during drying, was observed…
Two new compounds containing the title diphosphono-polyoxometalate anion and diprotonated ethylenediamine (enH(2)) or piperazine (ppzH(2)) countercations have been hydrothermally synthesized and structurally characterized ((enH(2))(4)[Mo(7)O(16)(O(3)PCH(2)PO(3))(3)].7H(2)O, triclinic, P(-)1, Z = 2, a = 10.3455(7) A, b…
The preparation of first-row transition-metal complexes of texaphyrin, a porphyrin-like, monoanionic penta-aza macrocyclic ligand, is reported. Specifically, the synthesis of organic-soluble Mn(II) (1), Co(II) (2), Ni(II) (3), Zn(II) (4), and Fe(III) (5) texaphyrin derivatives and their water-soluble counterparts (6-1…
The electron-transfer (ET) dynamics of a series of unusually rigid pi-stacked porphyrin-quinone (P-Q) systems, in which sub-van der Waals interplanar distances separate juxtaposed porphyryl, aromatic bridge, and quinonyl components of these assemblies, are reported. The photoinduced charge separation (CS) and thermal…
The sensitive detection and characterization of carbohydrates by means of a strategy based on surface-enhanced Raman spectroscopy is demonstrated. Spectra are obtained after injecting a small amount of saccharide solution onto a roughened silver substrate, with subsequent deposition of silver colloid. The sensitivity…
The adsorption behavior of 4-biphenylisocyanide (BPNC) has been studied by means of surface-enhanced Raman scattering (SERS). BPNC has been found to adsorb on silver and gold via the carbon lone pair electrons assuming a standing geometry with respect to the surfaces. The presence of the ν(CH) band in the SERS spectra…
An unusual composite hybrid material [Co4(phen)8(H2O)2(HPO3)2](H3O)3[PMoVI8VIV4O40(VIVO)2] 1 (phen = 1,10-phenanthroline) has been hydrothermally synthesized from a mixture of NH4VO3, Na2MoO4·2H2O, CoCl2·6H2O, phen, H3PO3 and water. It was characterized by elemental analysis, IR, UV-vis, XPS, EPR, TG and single crysta…
A sterically hindered biphenol 2,2‘-(2-methoxybenzylidene)bis(4-methyl-6- tert -butylphenol) (MEBBP-H 2 ) ( 1 ) has been prepared by the reaction of o -anisaldehyde with 2- tert -butyl-4-methylphenol in the presence of a catalytic amount of benzenesulfonic acid. Further reaction of compound 1 with a stoichiometric amo…
Standard enthalpies of formation, ionization potentials, electron affinities, and band gaps of finite-length [5,5] armchair and [9,0] zigzag single-walled carbon nanotubes (SWNTs) capped with C(30) hemispheres obtained by halving the C(60) fullerene have been computed at the B3LYP/6-311G* level of theory. Properties o…
We present the result of a systematic study of the tribological properties of industrial Polytetrafluorethylene (PTFE)-based coatings carried out with an atomic force microscope. A new characterization protocol allowed the reliable and quantitative assessment of the friction coefficient and adhesion forces at the sub-…
We present a new method for constant-pressure molecular dynamics simulation which is parameter free. This method is especially appropriate for finite systems in which a periodic boundary condition does not apply. Simulations on carbon nanotubes and Ni nanoparticles clearly demonstrate the validity of the method, from…
Several aspects of the theory of epitaxial crystal growth from atomic or molecular beams are developed from the perspective of statistical physics. Lectures are devoted to the rate equation theory of two-dimensional nucleation and its limitations; the growth of multilayer wedding cakes in the presence of strong step e…
Gold nanowires generated by mechanical stretching have been shown to adopt only three kinds of configurations where their atomic arrangements adjust such that either the [100], [111] or [110] zone axes lie parallel to the elongation direction. We have analyzed the relationship between structural rearrangements and ele…
A structural model of hydrogenated amorphous silicon containing an isolated dangling bond is used to investigate the effects of electron interactions on the electronic level splittings, localization of charge and spin, and fluctuations in charge and spin. These properties are calculated with a recently developed densi…
A molecular precursor approach involving simple grafting procedures was used to produce site-isolated titanium-supported epoxidation catalysts of high activity and selectivity. The tris(tert-butoxy)siloxy titanium complexes Ti[OSi(O(t)Bu)(3)](4) (TiSi4), ((i)PrO)Ti[OSi(O(t)Bu)(3)](3) (TiSi3), and ((t)BuO)(3)TiOSi(O(t)…
The deposition of a thin, metal film onto an array of spherical silica colloids, followed by dissolution of the colloidal template, produces metallic half-shells with nanometer-scale dimensions. Half-shells of gold, platinum, and palladium were fabricated, with diameters of the particles ranging from 100 to 500 nm, an…
Abstract A brief historical perspective relating the discovery of dendrimers and other dendritic polymers is presented. Dendritic polymers are recognized as the fourth major class of macromolecular architecture consisting of four sub‐ classes, namely, (1) random hyperbranched, (2) dendrigrafts, (3) dendrons, and (4) d…
New approaches to synthesize photostable thiol-capped CdTe nanocrystals are reported. Post-preparative size-selective precipitation and selective photochemical etching have been developed as methods providing an increase of photoluminescence quantum efficiency of the nanocrystals of up to 40%. Some advantages of thiol…