Materials Literature
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Electronic conductivity, σ EL, in solid-state films of alkanethiolate monolayer protected Au clusters (Au MPCs) occurs by a bimolecular, electron self-exchange reaction, whose rate constant is controlled by (a) the core-to-core tunneling of electronic charge along alkanethiolate chains and (b) the mixed valency of the…
The preparation of nanoscale lead sulfide (PbS) particles using a supercritical fluid processing technique is reported. The method is based on two simultaneous modifications to the conventional RESS (rapid expansion of supercritical solution) process. The first is to expand the supercritical solution into a liquid sol…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTA Novel Chiral Lead(II) Catalyst for Enantioselective Aldol Reactions in Aqueous MediaSatoshi Nagayama and Shū KobayashiView Author Information Graduate School of Pharmaceutical Sciences The University of Tokyo, CREST Japan Science and Technology Corporation (JST) Hong…
Die Elektrospray-Massenspektrometrie wurde erstmals benutzt, um anorganische oligomere Spezies in wässriger Lösung zu untersuchen. Unterschiedliche Doppelvier- und Doppeldreiringe konnten in Silicatlösungen verlässlich analysiert werden, wie mit der 29Si-NMR-Spektroskopie als unabhängiger Referenzmethode nachgewiesen…
Direct halogenations of polyoxometalates [NaPW11O39]6− and [PW9O34]9− led to [PW9O28Br6]3−, a molecular metal oxide with a fully brominated face (see picture). This methodology creates new opportunities for systematic chemistry at polyoxometalate surfaces.
A central Ag12 cluster core (see picture) that contains four more electrons than expected for a pure silver(I) compound is found in the title compound. This is confirmed by quantum chemical calculations at the DFT and MP2 level, which also show that d10–d10 interactions are not relevant for the cluster geometry.
A novel 5,10,15,20-tetraaryl-21-selenaporphyrin isomer with an inverted pyrrole ring, i.e., 5,10,15, 20-tetraaryl-2-aza-21-carba-22-selenaporphyrin (SeC-TArPH) has been produced by a [3 + 1] condensation of 2, 5-bis(phenylhydroxymethyl)selenophene and 5,10-ditolyltripyrrin. The reaction yielded 5,20-diphenyl-10,15-bis…
The relative viscosity of non-Newtonian concentrated emulsions of nearly spherical, non-Brownian droplets, in the absence of Coulombic and van der Waals interactions, is a function of four variables: the viscosity ratio ( K ), the volume fraction of dispersed phase (φ), the particle Reynolds number ( N Re,p ), and the…
Halogen-capped aniline trimers represent an important class of molecules that are no longer appropriate models for polyaniline, but they can nevertheless be expected to demonstrate useful properties in their own right. Such molecules are herein investigated by DFT (density functional theory) calculations of important…
π-Delokalisierung durch ausgedehnte Schichten hindurch besteht bei zweidimensionalen Netzwerkpolymeren der Formel [{M2(O2CCF3)4}2(TCNQ)(C7H8)3]∞ – dies geht sowohl aus den Strukturdaten als auch aus den spektroskopischen Daten hervor. Die Polymere setzen sich zusammen aus RuII,RuII- und RhII,RhII-Komplexen, die an TCN…
Hydroxyl radicals, generated by ionizing radiation in N2O saturated aqueous solutions, abstract H atoms from poly(methacrylic acid) at the methyl and methylene groups, and radicals 1 and 2 are formed, respectively. The reactions of the poly(methacrylic acid) radicals were investigated by pulse radiolysis (using optica…
The structure, packing, and charge distribution in molecules of nonlinear optical materials have been analysed with reference to their counterparts in centrosymmetric structures based on low temperature X-ray measurements. The systems studied are the centric and noncentric polymorphs of 5-nitrouracil as well as the di…
4-Bromo- and 4,5-dibromo-3,6-dibutoxyphthalonitrile have been prepared and treated with 3,6-didecylphthalonitrile in cross tetramerisation reactions in the presence of nickel acetate to afford monobromo- and dibromo-dibutoxyhexadecylphthalocyaninato nickel(II) complexes. Sonogashira and Stille coupling reactions on th…
Respiratory protection and industrial air purification are only two of the important applications of catalytic oxidation of CO at room temperature in undried air. This reaction proceeds with hydrous ruthenium(IV) oxide as the heterogeneous catalyst. In the example shown in the diagram (XCO=CO conversion) the CO concen…
We study the plasmon resonances for small two-dimensional silver particles (nanowires) with elliptical or triangular shapes in the 20 nm size range. While the elliptical particle has only two resonances, a well known fact, we demonstrate that the triangular particle displays a much more complex behaviour with several…
Electrospray mass spectrometry has been used for the first time to analyze inorganic oligomeric species in aqueous solutions. Different double-four rings and double-three rings could be reliably analyzed in silicate solutions, as proven by independent 29Si NMR spectroscopy. This technique might prove valuable in the a…
Photosensitizer/electron acceptor molecular cross-linked Au-nanoparticle arrays are assembled on indium-doped tin oxide (ITO) electrodes by a layer-by-layer deposition process. A Ru(II)−tris-(2,2‘-bipyridine)-cyclobis(paraquat- p -phenylene) catenane ( 1 ) or Zn(II)-protoporphyrin IX−bis( N -methyl- N ‘-undecanoate-4,…
The layered polysilicate kanemite can be used to synthesize the novel mesoporous silica KSW-2 (see picture), which contains square channels. The individual silicate sheets of kanemite are bent during the gradual leaching of hexadecyltrimethylammonium (C16TMA) surfactants from a layered C16TMA–kanemite complex.
The supramolecular dynamics of triplet excited states of the 2-naphthol@dendrimer (2-NpOH@ n -SBD) noncovalently bound complex have been studied by fluorescence spectroscopy and laser flash photolysis. By varying the acidity and dendrimer size, polyamidoamine dendrimers are shown to possess both nonspecific and specif…
The oxygen atom donor ability of the oxomanganese(V) porphyrin species 1 is comparable to that of myeloperoxidase compound I. This is one of the key findings of the reversible oxygen atom transfer reaction between 1 and bromide ion [Eq. (1)]. The well-behaved equilibrium 1⇌2 allows definition of the free energy of the…