Materials Literature
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Mesoporous materials get wired: Micelles of the thienyl-substituted ammonium ion 1 in aqueous ammonia solution are applied as matrices for the formation of mesoporous silicate particles from tetraethylorthosilicate. After oxidation with FeCl3 and treatment with HF, polymeric wires with a bimolecular diameter of 3 nm a…
There is much debate about the photoluminescence (PL) mechanisms of the nanoscale Si/Si oxide systems containing oxidized porous silicon and a nanoscale-Si-particle (NSP)---embedded Si oxide deposited by chemical vapor deposition, sputtering, or Si-ion implanting into Si oxide. In this paper, we suggest that two compe…
We present calculations of the optical absorption spectra of clusters ${\mathrm{SiH}}_{4},$ ${\mathrm{Si}}_{10}{\mathrm{H}}_{16},$ ${\mathrm{Si}}_{17}{\mathrm{H}}_{36},$ ${\mathrm{Si}}_{29}{\mathrm{H}}_{24},$ and ${\mathrm{Si}}_{35}{\mathrm{H}}_{36},$ as determined from two different methods: the Bethe-Salpeter equati…
We describe fluorescence visualization of highly stable worm micelle superpolymers. The worm micelles are self-assembled in water from nonionic, block copolymer amphiphiles. By blending and polymerizing inert and cross-linkable copolymers, we form micelles up to tens of microns long with persistence lengths that conti…
Democratic behavior: A strong bias for the amplification of assemblies, the composition of which reflects the overall composition of the library, can be observed in selection processes with dynamic combinatorial libraries. As a consequence, it is not necessarily the assembly with the highest affinity to a given target…
Solvothermal techniques allow the crystallization of high nuclearity products that are otherwise inaccessible by conventional techniques, directly from the reaction mixture. By this method, the reaction of the triangular species [Fe3O(OAc)6(H2O)3]Cl with benzotriazole (BtaH) produces an [Fe14] cluster (depicted) with…
Crypt analysis: The reaction of manganese(II) chloride with sodium hydroxide, di-(2-pyridyl)-ketonoxime, and sodium azide yields a metallacryptate consisting of 26 manganese centers, namely, four MnII (see picture; gold spheres) and 22 MnIII ions (green, aqua, and blue spheres). Results obtained from ac SQUID magnetic…
Composite ab initio CBS-Q and G3 methods were used to calculate the bond dissociation energies (BDEs) of over 200 compounds listed in CRC Handbook of Chemistry and Physics (2002 ed.). It was found that these two methods agree with each other excellently in the calculation of BDEs, and they can predict BDEs within 10 k…
[Tetrakis ( N -methylpyridyl) porphyrinato] cobalt (CoTMPyP) and 1:12 silicotungstic acid (SiW 12 ) were alternately deposited on a 4-aminobenzoic acid (4-ABA) -modified glassy carbon electrode through a layer-by-layer method. The resulting organic−inorganic hybrid films were characterized by cyclic voltammetry (CV) a…
We have grown high-quality single crystals of the colossal-magnetoresistance (CMR) material La0.7Ca0.3MnO3 by using the laser heated pedestal growth (LHPG) method. Samples were grown as fibers of different diameters, and with lengths of the order of centimeters. Their composition and structure were verified through X-…
Novel photochromic single crystals composed of three different kinds of diarylethenes, 1,2-bis(3,5-dimethyl-2-thienyl)perfluorocyclopentene (1a), 1,2-bis(2,5-dimethyl-3-thienyl)perfluorocyclopentene (2a), and 1,2-bis(2-methyl-5-p-methoxyphenyl-3-thienyl)perfluorocyclopentene (3a), have been prepared. The three-compone…
A new dual-function hybrid molecular material has been obtained from the organic donor bis(ethylenedithio)tetraselenafulvalene and the honeycomb oxalate-based bimetallic network [MnCr(ox)3]-. This multilayer material consists of layers of the inorganic anionic 2D network, responsible for the appearance of ferromagneti…
We show that in YVO3 new hard phonons gradually become zone center active below ~210 K verifying that a lattice phase transition takes place at about that temperature. The Debye-Waller factor found from EXAFS measurements show an additional disorder below 150K seen as a departure from the thermal behavior. We bring up…
This paper reports on the synthesis and characterization of oversized titania nanosheets derived from single crystals of a potassium lithium titanate, K 0.8 Ti 1.73 Li 0.27 O 4 . The single crystals with a lateral size of over 1 mm were obtained via a melt and recrystallization process in a flux melt. The crystals wer…
From disorder to order and back: Contrary to all earlier studies on [Fe(2-pic)3]Cl2⋅EtOH (pic=picolylamine), an ordered phase (IP) with two crystallographically different iron sites was found between disordered high-spin (HS) and low-spin (LS) phases. The picture shows the average FeN distances of all three phases.
A net change: A fully reversible ligand substitution involving coordination/uncoordination of gaseous water and pyrimidine induces the repetitive allosteric transformation of three interpenetrated nets into a single three-dimensional net. The transformation does not affect the crystallinity of the sample but alters si…
The focus of this review is on host-guest composites with photonic antenna properties. The material generally consists of cylindrical zeolite L crystals the channels of which are filled with dye molecules. The synthesis is based on the fact that molecules can diffuse into individual channels. This means that, under th…
We report on the synthesis of semiconductor nanocrystals of PbS, ZnS, CdS, and MnS through a facile and inexpensive synthetic process. Metal-oleylamine complexes, which were obtained from the reaction of metal chloride and oleylamine, were mixed with sulfur. The reaction mixture was heated under appropriate experiment…
Abstract The effects of short‐chain branch (SCB) length on the calibration of temperature rising elution fractionation (TREF) were examined. Samples of ethylene–hexene, ethylene–octene, and a novel polyolefin produced using Eastman Chemical Company's Gavilan catalyst technology were used to prepare TREF calibration cu…
Effect of the magnetic field on the martensitic transformation of Co-Ni-Al single-crystal was investigated by differential thermal analysis (DTA) and the in-situ microstructure observation under magnetic field. The martensitic transformation temperatures Ms and Mf of the Co<sub>34.5</sub>Ni<sub>35.5</sub>Al<sub>30</su…