Materials Literature
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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…
A series of three perylene tetracarboxylic acid bisimide dyes 3a-c bearing phenoxy substituents at the four bay positions of the perylene core were synthesized and their complexation behavior to complementary ditopic dialkyl melamines 8a-c was investigated. Binding constants and Gibbs binding energies for the hydrogen…
π delocalization throughout the extended layers of two-dimensional network polymers of the type [{M2(O2CCF3)4}2(TCNQ)⋅3 (C7H8)]∞, which consist of RuII,RuII and RhII,RhII complexes coordinated to TCNQ molecules, is evident from the available structural (see picture for Ru analogue) and spectroscopic data. TCNQ=7,7,8,8…
Crystal-engineering strategies have been systematically developed for the rational design by self-assembly of diverse metalloporphyrin molecular-sieve materials. Cooperative coordination and hydrogen bonding algorithms of molecular recognition proved particularly useful for this aim. The supramolecular concepts used i…
A new formalism to calculate the transmission coefficient t of electrons from a material L into the same material L through a barrier B is presented. The barrier B is arbitrary and can be metallic, semiconducting or insulating. The important feature of this formalism is that it starts from the electronic structure of…
We introduce an electrostatic model including charge transfer, which is shown to account for the observed B-site ordering in Pb-based perovskite alloys. The model allows charge transfer between A-sites and is a generalization of Bellaiche and Vanderbilt's purely electrostatic model. The large covalency of Pb^{2+} comp…
Based on spin-density functional theory we calculate the electronic structure of a tunnel junction consisting of two magnetic Fe layers separated by an insulating vacuum barrier selfconsistently. For the conductance the Landauer formula is evaluated in the ballistic limit as function of the magnetic configuration. Bas…
We formulate and prove a variational principle (in the sense of thermodynamics) for random domino tilings, or equivalently for the dimer model on a square grid. This principle states that a typical tiling of an arbitrary finite region can be described by a function that maximizes an entropy integral. We associate an e…
Determination of the tendencies of amino acids to form alpha-helical and beta-sheet structures has been important in clarifying stabilizing interactions, protein design, and the protein folding problem. In this study, we have determined for the first time a complete scale of amino acid propensities for another importa…
Titania- and zirconia-supported gold particles of 1−5 nm size, prepared by various routes of synthesis, were employed in the partial hydrogenation of acrolein. In-depth characterization of their structural and electronic properties by electron microscopy, electron paramagnetic resonance, and optical absorption spectro…
At least in principle, a very large number of rubber-plastic blends are possible (Corish and Powell, 1974; Dunn, 1976). However, in this chapter we will be concerned with those compositions, which are soft or flexible and which have rubber-like elasticity, in that they retract forcibly from large deformations. Such co…