Materials Literature
按标题、摘要、年份、主题和来源检索公开元数据。结果保留作者、摘要、分类与原始来源链接。
Highly conductive hybrid Langmuir−Blodgett (LB) films of MoS 2 and amphiphilic compounds such as alkylammonium halides and alkylamines were fabricated. The interlayer spacing of the LB films depended on the organic species. The lateral conductivity of 10-layer LB films was in the range of 10 1 to 10 2 S cm - 1 and dec…
Exchange coupling constants for di-μ-oxo-bridged copper(II) dimers with varying Cu−O−Cu bond angles have been calculated by means of density functional, broken symmetry (BS) techniques. The surprinsingly large ferromagnetism recently computed by Ruiz et al. [ Chem. Commun. 1998, 2767] for such model complexes has been…
Chemical transport experiments are a valuable aid of great potential in the synthesis and thermochemical characterization of solids. Compounds of interest can often only be crystallized by this method. The use of a transport balance allows very detailed observations, particularly of the course of the experiment over t…
The transient kinetics of the reaction between NO and CO on clean Rh(111) surfaces have been studied using molecular beams in conjunction with mass spectrometry detection. The changes in the partial pressures of the reactants (CO and NO) and products (N 2 and CO 2 ) as a function of time have been used as a measure of…
The homologous dendrimers G0 to G3, which consist of 3, 9, 21, and 45 viologens, behave as electron sponges and exhibit an electrochemically switchable, generation-dependent, intramolecular charge transfer (CT) complexation (see schematic diagram of G3).
The ring-opening polymerization of ε-caprolactone has been initiated by [tris(hexamethyldisilyl)amide]yttrium in the presence of an excess of 2-propanol. This initiating system is very active even at high alcohol-to-Y molar ratio. Polymers with controlled molecular parameters ( M n, end groups) and low dispersity are…
A self-assembly layer-by-layer (LBL) technique was used for the sequential adsorption of polycation, poly(diallyldimethylammonium chloride) (PDDA) and polyanion, sulfonated polyaniline (SPANI) on glass, indium-tin-oxide (ITO) coated glass plates, polystyrene sulfonate (PSS)/glass and PSS/ITO surfaces, respectively. Th…
A coupling of size exclusion chromatography (SEC) and liquid chromatography at the critical adsorption point (LC CAP) has been applied to simultaneous discrimination of stereoregular poly(ethyl methacrylate)s (PEMAs) according to their molar mass and tacticity. The two-dimensional SEC/LC CAP separations were carried o…
Thin films of solvent-free molecule-based magnets [Cp*2Fe]•+[TCNE]•- and V(TCNE)x are grown by chemical vapor deposition on KBr pellets. [Cp*2Fe]•+[TCNE]•- films are crystalline and magnetically order at 3.7 K. Despite of their faceted grain morphology, V(TCNE)x films are amorphous. They exhibit field-dependent magnet…
Photoelectrochemical cells have been constructed by depositing monolayers of oriented covalently linked zinc/free base porphyrin heterodimers onto ∼30 nm nonporous layers of TiO 2 on ITO, deposited by metal−organic chemical vapor deposition (MO-CVD), and onto ∼100 nm porous, nanostructured TiO 2 layers, spin-coated fr…
The cure reactions of phenylethynyl end-capped polyimides were investigated using solid-state 13 C magic-angle spinning (MAS) nuclear magnetic resonance (NMR). A 13 C-labeled model compound ( 13 C-PEPA-3,4‘-ODA) and an imide oligomer ( 13 C-PETI-5) were synthesized and characterized. The thermal cure process for 13 C-…
The electrochemical and photophysical properties of a variety of neutral pi-associated [2]catenanes have been explored by using cyclic voltammetry, absorption and luminescence spectrophotometry and the measurement of exited-state lifetimes. Several trends that could be correlated with interactions between the mechanic…
Chemical oxidation of the linear tricobalt compound Co 3 (dpa) 4 Cl 2 ( 1 ) with 1 equiv of NOBF 4 yields the one-electron oxidized species [Co 3 (dpa) 4 Cl 2 ] + ( 1 + ), which crystallizes from dichloromethane as a solvate [Co 3 (dpa) 4 Cl 2 ][BF 4 ]·2CH 2 Cl 2 ( 2 ·2CH 2 Cl 2 ). The crystal structure of 2 · x CH 2…
The kinetic stability of the complex [Gd(DTPA)]2- (H5DTPA = diethylenetriamine-N,N,N',N",N"-pentaacetic acid), used as a contrast-enhancing agent in magnetic resonance imaging (MRI), is characterised by the rates of the exchange reactions that take place with the endogenous ions Cu2+ and Zn2+. The reactions predominan…
The rheological properties of different generations of hyperbranched polyesters in 1-methyl-2-pyrrolidinone solvent and their blends with a poly(2-hydroxyethyl methacrylate) are examined in this study. All the hyperbranched polyester solutions exhibit Newtonian behavior, with steady shear viscosities independent of sh…
The molecular arrangements of three different alkyl-substituted oligothiophenes both in two-dimensional adsorbed layers at a substrate interface and in bulk three-dimensional crystals were studied. Scanning tunneling microscopy (STM) was used to investigate the ordering of the conjugated oligomers in two-dimensional l…
Bimetallic gold and platinum particles of the Pt−Au and Au−Pt core−shell type are prepared using hydrogen reduction and radiolysis techniques. The optical absorption spectra are recorded and compared to various Au−Pt particles described in the literature. Au core Pt shell particles catalyze the hydrogen reduction of s…
Control over self-assembling polymers is characterized by size-exclusion chromatography: The polymer, formed from cobalt porphyrins functionalized with two pyridine ligands, organizes to a high molecular mass (>100 kDa) in solution (see scheme). The mean molecular mass can be precisely controlled by adding monofunctio…
Different relaxation rates of water protons are enhanced by a contrast agent for magnetic resonance imaging (MRI). A supramolecular adduct of poly-β-cyclodextrin and [(MnII(tpps)]4− is described. Oxidation of the manganese center to MnIII causes a marked decrease in the observed relaxivity r1p (see scheme), which make…
Isotactic (it-) and syndiotactic (st-) poly(methyl methacrylate)s (PMMAs) were synthesized by anionic polymerization in toluene at −78 °C with t -C 4 H 9 MgBr and t -C 4 H 9 Li/(C 2 H 5 ) 3 Al, respectively, as initiators. Polymers were assembled by the stepwise immersion of a 9-MHz quartz-crystal microbalance (QCM) a…