Materials Literature
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Self-aggregation of water-soluble pyridinium-substituted porphyrins with functionalized calixarenes leads to well-defined pH-tunable stoichiometries. Two assemblies with different porphyrin:calixarene ratios that crystallized at pH 2 and 6 have been structurally characterized. The Job plots of Soret band broadenings i…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTFirst Unequivocal Observation of the Whole Bell-Shaped Energy Gap Law in Intramolecular Charge Separation from S2 Excited State of Directly Linked Porphyrin−Imide Dyads and Its Solvent-Polarity DependenciesNoboru Mataga, Haik Chosrowjan, Yutaka Shibata, Naoya Yoshida,…
complex of an N-alkyloxysalicylidenyl-N'-ethyl-N-ethylenediamine ligand, shown as a computer model in the picture, is the first compound in which spin-crossover (SC) and liquid-crystalline (LC) properties coexist. This synergy should allow the magnetic and optical properties of SC compounds to be combined with the sen…
ADVERTISEMENT RETURN TO ISSUEPREVNoteNEXTSelective Aerobic Oxidation of Alcohols with a Combination of a Polyoxometalate and Nitroxyl Radical as CatalystsRevital Ben-Daniel, Paul Alsters, and Ronny NeumannView Author Information Department of Organic Chemistry, Weizmann Institute of Science, Israel, 76100, and DSM Res…
The transparent, double bridged-(R)-spiral three-dimensional polymeric complex K0.4[Cr(CN)6][Mn(S)-pn](S)-pnH0.6 ((S)-pn=(S)-1,2-diaminopropane) has been synthesized and characterized (see X-ray structure; Cr: brown, Mn: red, C: gray, N: blue, K: green). Magnetic measurements on the complex show that the MnII and CrII…
This paper reports the application of ligand-field electronic absorption spectroscopy to probe Co(2+) dopant ions in diluted magnetic semiconductor quantum dots. It is found that standard inverted micelle coprecipitation methods for preparing Co(2+)-doped CdS (Co(2+):CdS) quantum dots yield dopant ions predominantly b…
Enforced ligand dissociation as a result of steric interactions between ZnII porphyrin units and the N atoms of pyridylphosphane ligands determines the catalytic properties of the encapsulated transition metal complexes (see picture). These assemblies show increased catalytic activity in the palladium-catalyzed Heck r…
Lanthanide complexes of europium and terbium ions with hydrogen phthalate [Eu(Hphth) 3 and Tb(Hphth) 3, respectively, Hphth = hydrogen phthalate] were incorporated into poly(vinyl pyrrolidone) (PVP) matrix. Transmission electron microscopy (TEM) results showed that the lanthanide complexes, with a mean diameter about…
The phase behavior of a set of high hard block content (50% to 100% hard segment by weight) linear thermoplastic polyurethanes has been investigated mainly via differential scanning calorimetry (DSC). The soft segment was based on a polypropylene oxide polyol end-capped with ethylene oxide and the hard segment on a 4,…
The uniaxial elastic-plastic deformation process is considered. Mathematical model of this process was built. According to this model all stable static states form the lattice, which is called the delta-lattice.
The kp method is used to analyze the problem of intervalley Γ-X_z interaction of conduction band states in the (001) lattice-matched III-V semiconductor heterostructures. A convenient basis for expansion of the wave function is systematically selected and a multiband system of equations is derived for the envelope fun…
In this review article we briefly summarize the main experimental properties of (III,Mn)V ferromagnets and outline several different but related approaches that have been explored in an effort to gain insight into these materials. The main body of the paper deals with the development of the semi-phenomenological model…
In this paper we review the latest achievements of density functional theory in understanding the physics of diluted magnetic semiconductors. We focus on transition metal doped III-V semiconductors, which show spontaneous ferromagnetic order at relatively high temperature and good structural compatibility with existin…
Mixed-valence perovskite manganites (Re 1- x A x MnO 3 where Re = rare earth, A = alkaline earth) provide a unique opportunity to study the relationships between the structure and the magnetotransport properties due to an interplay among charge carriers, magnetic coupling, orbital ordering and structural distortion. T…
Supramolecular complex formation imparts stability and substrate selectivity to a simple manganese-porphyrin-based epoxidation catalyst. Lewis acid/Lewis base directed assembly was used to encapsulate the epoxidation catalyst within a supramolecular square structure to form an enzyme-like catalyst system. The "molecul…
Insight into the location, state, and function of a promoter in heterogeneous catalysis was obtained through atomic-resolution in situ transmission electron microscopy. In the most active ruthenium catalyst for ammonia synthesis known so far, the barium promoter is shown to be located in two different phases in the ca…
We describe preparation and magnetic properties of an organic pi-conjugated polymer with very large magnetic moment and magnetic order at low temperatures. The polymer is designed with a large density of cross-links and alternating connectivity of radical modules with unequal spin quantum numbers (S), macrocyclic S =…
ADVERTISEMENT RETURN TO ISSUEPREVNoteNEXTModeling the Barrier Properties of Polymer-Layered Silicate NanocompositesR. K. BharadwajView Author Information Avery Research Center, 2900 Bradley Street, Pasadena, California 91107 Cite this: Macromolecules 2001, 34, 26, 9189–9192Publication Date (Web):November 16, 2001Publi…
Femtosecond x-ray and visible pulses were used to probe structural and electronic dynamics during an optically driven, solid-solid phase transition in VO(2). For high interband electronic excitation (approximately 5 x 10(21) cm(-3)), a subpicosecond transformation into the high-T, rutile phase of the material is obser…
Thin films of composite germanium/silicon (Ge/Si) were prepared by pulsed laser ablation alternately on Ge and Si materials on a rotary target, followed by vacuum deposition of the ablated materials on an ultraclean glass substrate. X-ray diffraction and atomic force microscopy phase analysis confirmed that the film s…