Materials Literature
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The structures and energies of B+13, observed experimentally to be an unusually abundant species among cationic boron clusters, have been studied systematically with B3LYP/6–31G* density functional theory. The most thermodynamically stable B+12 and B+13 clusters are confirmed to have planar or quasiplanar rather than…
Two series of segmented polyurethanes, one containing 50% soft segments and the other with 70% soft segments were synthesized. Chemical crosslinks were introduced through the hard segment in a controlled way. Chemical polyurethane networks were characterized by swelling. The effect of the degree of crosslinking on pro…
Curvilinear coordinates, first introduced by F. Gygi for valence-only electronic systems within the local-density functional theory, can be used to describe both core and valence electrons in electronic-structure calculations. A simple and quite general coordinate transformation results in a large, yet affordable plan…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTLewis Acid Mediated Functionalization of Porous Silicon with Substituted Alkenes and AlkynesJillian M. Buriak and Matthew J. AllenView Author Information Department of Chemistry, 1393 Brown Laboratories Purdue University, West Lafayette, Indiana 47907-1393 Cite this: J…
A limited mobility nonequilibrium solid-on-solid dynamical model for kinetic surface growth is introduced as a simple description for the morphological evolution of a growing interface under random vapor deposition and surface diffusion bias conditions. Large scale stochastic Monte Carlo simulations using a local coor…
Preparation and properties of poly(arylamine)s prepared by organometallic polycondensation are described. Dehalogenative polycondensation of 4,4‘-dibromodiphenylamine, Br−PhNHPh−Br, with a zerovalent nickel complex affords soluble poly(diphenylamine-4,4‘-diyl), P(DPA) ( n Br−PhNHPh−Br + n Ni (0) Lm → P(DPA)), with M n…
A series of high-temperature and chemically stable chromophores were covalently attached onto the polyquinoline backbones. These NLO side-chain polyquinolines possess high glass transition temperature (Tg > 200 °C), excellent processibility, thermal stability, and electrooptical properties. Poling results of these pol…
A variety of Pd and Pt complexes of the type [(P−P)M(μ-OH)] 2 2+ (M = Pd, Pt; P−P = a series of tetraphenyldiphosphines) were tested in the Baeyer−Villiger oxidation of ketones with hydrogen peroxide. The effect of the diphosphine−metal ring size on the catalytic activity indicates that the larger the ring, the better…
A hybrid dendrimer with alternating Si and Ge atoms in the chains has been synthesized by the divergent growth method using Me(PhMe 2 Ge) 2 SiLi as a branching reagent. The structure of the first generation of the hybrid permethylated dendrimer 1G has been established by X-ray crystallography.
The intercalation of a cubic octamer derived from the controlled hydrolysis of (3-aminopropyl)triethoxysilane with smectite clays has been studied. The organosilicon cubanes are adsorbed in amounts exceeding the cation exchange capacity of the mineral. The excess quantity is incorporated in the form of physically adso…
In this Letter, we consider a neutral system of mobile positive and negative charges confined on the surface of curved films. This may be an appropriate model for: i) a highly charged membrane whose counterions are confined to a sheath near its surface; ii) a membrane composed of an equimolar mixture of anionic and ca…
The thermal stability of a series of cobalt and nickel molybdates (AMoO 4 · n H 2 O, α-AMoO 4, and β-AMoO 4; A = Co or Ni) was examined using synchrotron-based time-resolved X-ray powder diffraction (XRD). The results of X-ray absorption near-edge spectroscopy (XANES) indicate that the Co and Ni atoms are in octahedra…
The weighted density approximation, its implementation and its application to ferroelectric materials is discussed. Calculations are presented for several perovskite oxides and related materials. In general the weighted density approximation is found to be superior to either the local density or generalized gradient a…
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” opt…
We have studied the size effect of the homologues of the α,ω-diphenylpolyenes series, with two, three and four double bonds, on the formation of nanotubes with γ-cyclodextrin. The data show that only the two longest polyenes facilitate the formation of tubular structures when mixed with the γ-cyclodextrin in the appro…
By using small-angle X-ray scattering (SAXS) and differential scanning calorimetry (DSC) we studied the thermal structural transition of lysozyme in the temperature range from 20 to 85 °C at pH 1.2, 3.9, and 7.0. α-Lactalbumin was used as a control. We found that the onset temperature determined from the DSC thermogra…
Isotopic labeling of Bombyx mori silk fibroin was achieved biosynthetically using two approaches. First, labeled fibroin was achieved by feeding silk worms [ 13 C 1 ]Gly and [ 13 C 1 ]Ala along with an artificial diet. Second, in vitro production of [ 15 N]Gly and [ 15 N]Ala labeled B. mori silk fibroin was accomplish…
Excited states of free base chlorin (FBC), free base Bacteriochlorin (FBBC), pheophytin a (Pheo a ), and chlorophyll a (Chlo a ), which are derivatives of free base porphine (FBP), were calculated by the SAC (symmetry adapted cluster)/SAC−CI (configuration interaction) method. The results reproduced well the experimen…
4,4‘‘-Diamino-5‘-phenyl- or 4-alkoxyphenyl- m -terphenyl and 4,4‘‘-dicarboxy-5‘-phenyl- m -terphenyl were synthesized through pyrylium salts and used for the preparation of rigid-rod polyamides and polyimides. The polymers were characterized by inherent viscosity, elemental analysis, FT-IR, UV−vis, 1 H NMR, 13 C NMR,…
Novel optically active aromatic isocyanates, 3-(( S )-(α-methylbenzyl)carbamoyl)phenyl isocyanate (( S )-3MBCPI) ([α] 365 25 +63°) and 4-(( S )-(α-methylbenzyl)carbamoyl)phenyl isocyanate (( S )-4MBCPI) ([α] 365 25 +181°), were synthesized and homopolymerized or copolymerized with m -methoxyphenyl isocyanate ( m MeOPI…