Materials Literature
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Compositional variation of magnetoresistance (MR) ratio with silver excess stoichiometry in ${\mathrm{Ag}}_{2+\ensuremath{\delta}}\mathrm{Se}$ samples has been studied employing a synthetic approach to prepare instantly a series of bulk silver selenide compounds using microwave energy. Bulk density >99% is achieved…
We have previously reported the use of titanium alkoxide complexes as initiators for the living polymerization of isocyanates. In this paper, we present the synthesis of a trimetallic initiator, 2, comprised of three titanium alkoxides connected to a central organic core and the use of this catalyst to form three-arm…
Toughness enhancement of brittle amorphous polymers can be obtained via microstructural adjustments, resulting effectively in a removal of intrinsic strain softening on the mesoscale via a decrease in yield stress and an increase in strain hardening. Generally the introduction of a dispersed soft phase is required wit…
Oligomeric peptides can be designed which undergo one-dimensional self-assembly in solution to form beta-sheet tapes a single molecule in thickness and micrometers in length.(1) In this paper, we present the first systematic investigation of the size, shape, dynamics, and interactions of beta-sheet tapes formed by a s…
In this paper, we report differential scanning calorimetry studies of the temperature and molar mass dependences for the primary and secondary crystallization behavior of bisphenol A polycarbonate (BAPC). The molar mass dependence of the crystallization rate is found to be much stronger during primary than during seco…
We have investigated electrochemical switching of excited-state electronic energy migration in two optoelectronic gates with different architectures. Each gate consists of diarylethyne-linked subunits: a boron-dipyrrin (BDPY) input unit, a Zn-porphyrin transmission unit, a free-base-porphyrin (Fb-porphyrin) output uni…
Extremely large carbon tubes, some exceeding 5 microm in diameter, were produced with both laser and electric arc techniques using graphite, a transition metal catalyst, and a reactive third-body gas. We have named these structures carbon megatubes. They are the first carbonaceous tubes large enough to observe using o…
Direct self-polycondensation of an AB 2 type monomer ( 1 ) followed by chemical modification with a branched reagent ( 2 ) afforded a precursor. Chemical imidization of the precursor gave a hyperbranched aromatic polyimide ( 12 ) with a weight-average molecular weight of 98 000 and an inherent viscosity of 0.13 dL/g.…
The complex [Fe[HC(3,5-Me(2)pz)(3)](2)](BF(4))(2) (pz = pyrazolyl ring) undergoes a phase transition that occurs concomitantly with a thermally induced spin conversion between the high-spin (HS, S = 2) and low-spin (LS, S = 0) states. Above 204 K the compound is completely HS with the structure in the C2/c space group…
Colloidal gold particles synthesized in water have been capped with octadecanethiol (ODT) molecules rendered water-soluble by threading with α-cyclodextrin (α-CD) molecules. Thereafter, the gold nanoparticles could be transferred into an organic solvent such as chloroform by vigorous shaking of a biphasic mixture of t…
As postulated by Fowler and Ugalde [ J. Phys. Chem. A 2000, 104, 397], the lowest-energy B 13 + isomer proved to be highly aromatic. The topological resonance energy of this cationic boron cluster is positive in sign and very large in magnitude. This constitutes the definitive reason B 13 + is kinetically stable and p…
The network structure of UV-cured acrylates was analyzed by dynamic mechanical experiments, 1 H T 2 NMR relaxation, and 13 C NMR spectroscopy. Photocured mixtures of difunctional (poly(ethylene glycol) diacrylate) and monofunctional (2-ethylhexyl acrylate) were studied. The mean cross-link density and fraction of dang…
In the field of inherently conducting polymers, polyaniline (Pani) has elicited tremendous interest due to its promising electrical properties and unique redox tunability. Synthetic routes involving the use of polyelectrolytes have significantly improved the processability of polyaniline. Recently, a template guided s…
Tetranuclear lanthanide-hydroxo complexes of the general formula [Ln(4)(mu(3)-OH)(4)(AA)(x)(H(2)O)(y)](8+) (1, Ln = Sm, AA = Gly, x = 5, y = 11; 2, Ln = Nd, AA = Ala, x = 6, y = 10; 3, Ln = Er, AA = Val, x = 5, y = 10) have been prepared by alpha-amino acid controlled hydrolysis of lanthanide ions under near physiolog…
We have developed a new methodology that affords regioisomerically pure trans-A2B-corroles. The corrole formation reaction involves the acid-catalyzed condensation of a dipyrromethane and an aldehyde followed by oxidation with DDQ. Optimal conditions for the condensation were identified after examining various reactio…
We report the self-assembly of single crystals of single-walled carbon nanotubes (SWCNTs) using thermolysis of nano-patterned precursors. The synthesis of these perfectly ordered, single crystals of SWCNTs results in extended structures with dimension on the micrometer scale. Each crystal is composed of an ordered arr…
The effect of cation size on the rate and energy of electron transfer to [(M(+))(acceptor)] ion pairs is addressed by assigning key physicochemical properties (reactivity, relative energy, structure, and size) to an isoelectronic series of well-defined M(+)-acceptor pairs, M(+) = Li(+), Na(+), K(+). A 1e(-) acceptor a…
Electronic and lattice properties of MgB{$_2$} under uniaxial and hydrostatic compression are calculated. Lattice properties are optimized automatically by using the first-principles molecular dynamics (FPMD) method. Features of the electronic band structures under uniaxial and hydrostatic compression are quite differ…
Density Functional Theory (DFT) calculations show that the reversible Sn/Ge(111) $\sqrt{3}\times\sqrt{3} \leftrightarrow 3\times3$ phase transition can be described in terms of a surface soft phonon. The isovalent Sn/Si(111) case does not display this transition since the $\sqrt{3}\times\sqrt{3}$ phase is the stable s…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTHigh Dissolution and Strong Light Emission of Carbon Nanotubes in Aromatic Amine SolventsYi Sun, Stephen R. Wilson, and David I. SchusterView Author Information Department of Chemistry and Center for Advanced Materials and Nanotechnology New York University, New York,…