Materials Literature
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Unique temperature-dependent syn-anti conformational switching in bis- and monozinc ethane-bridged porphyrin dimers takes place in nonpolar solvents containing a small amount of alcohol (1−5%). These dimers adopt a syn conformation at any studied temperatures in the absence of alcohol added, while, in the presence of…
The formation of a molecular assembly composed of a naturally occurring peptide with a helical structure was investigated. Gramicidin A, a 15-mer peptide antibiotic, was conjugated with poly(ethylene glycol) (PEG, average molecular weight 600). This peptide conjugate formed vesicles with an unilamellar membrane in wat…
The nature of the structural ordering within semicrystalline poly(3-dodecylthiophene) films has been analyzed using a Warren−Averbach line-shape analysis which includes up to five orders of the ( h 00) lattice reflections. This analysis yields a semiquantitative measure of the volume averaged crystallite sizes, the la…
Nonlinear optical (NLO) properties of two series of octupolar molecules are investigated to establish the structure−NLO-property relationships by carrying out the ab initio (HF/6-31G) calculations of the molecular polarizability (α), the first hyperpolarizability (β), and the second hyperpolarizability (γ). It is foun…
Non-heme Fe(II) proteins form stable nitrosyl adducts. However, there are few synthetic examples of structurally characterized non-heme iron nitrosyl complexes, especially those that are coordinatively unsaturated. Presented herein is a series of non-heme {Fe−NO} 7 complexes with trigonal bipyramidal coordination geom…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTAntiferromagnetic Organic Metal Exhibiting Superconducting Transition, κ-(BETS)2FeBr4 [BETS = Bis(ethylenedithio)tetraselenafulvalene]Emiko Ojima, Hideki Fujiwara, Kiyonori Kato, Hayao Kobayashi, Hisashi Tanaka, Akiko Kobayashi, Madoka Tokumoto, and Patrick CassouxView…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTA New Approach for the Design of Supramolecular Recognition Units: Hydrogen-Bonded Molecular DuplexesBing Gong, Yinfa Yan, Huaqiang Zeng, Ewa Skrzypczak-Jankunn, Yong Wah Kim, Jin Zhu, and Harold IckesView Author Information Department of Chemistry The University of To…
We study a two-dimensional honeycomb lattice gas model with both nearest- and next-nearest-neighbor interactions in a staggered field, which describes the surface of stoichiometrically binary crystal. We calculate anisotropic step tension, step stiffness, and equilibrium island shape, by an extended random walk method…
A Monte-carlo (MC) simulation procedure has been developed where the pair bond energies are allowed to take into account the various coordination numbers of surface atoms and the presence of adsorbates. The pair bond energies are calculated from partial bond energies of atoms which, in turn, are calculated from modifi…
We present a multigrid algorithm for self consistent solution of the Kohn-Sham equations in real space. The entire problem is discretized on a real space mesh with a high order finite difference representation. The resulting self consistent equations are solved on a heirarchy of grids of increasing resolution with a n…
We apply first principles calculations to study the opening of single-wall carbon nanotubes (SWNT's) by oxidation. We show that an oxygen rim can stabilize the edge of the open tube. The sublimation of CO$_2$ molecules from the rim with the subsequent closing of the tube changes from endothermic to exothermic as the t…
Open-system density functional theory may be formulated in terms of ensemble averages arising from interaction with a bath. The system is allowed to exchange particles with the bath and the states in the ensemble average are those corresponding to integer numbers of particles. The weights in the ensemble average are t…
Proximity-induced superconductivity in single-walled carbon nanotubes below 1 kelvin, both in a single tube 1 nanometer in diameter and in crystalline ropes containing about 100 nanotubes, was observed. The samples were suspended between two superconducting electrodes, permitting structural study in a transmission ele…
The microphase morphology of a polystyrene- block -polybutadiene- block -poly(ε-caprolactone) SBC triblock copolymer is studied through transmission electron microscopy. Even though crystallization of the PCL block takes place well below the PS glass transition, lamellar microphases and the formation of well-defined s…
Photodegradation of solvent-cast collagen type I films and photostabilization of collagen by vitamin E were studied. These films were exposed to polychromatic radiation from a medium-pressure mercury lamp or monochromatic radiation from the Okazaki Large Spectrograph (OLS). Changes in the molecular structure of collag…
We described in this work new glucose-persubstituted poly(amidoamine) dendrimers. The physicochemical properties of these new amphiphilic dendrimers were investigated in water, showing that these new amphiphilic dendrimers were able to solubilizate increasing quantities of hydrophobic compounds (pyrene or aromatic ket…
Reactions of HO(O)P(O t Bu) 2 with Al 2 Me 6 and [Al(O i Pr) 3 ] 4 gave the new molecular aluminum phosphate complexes [Me 2 AlO 2 P(O t Bu) 2 ] 2 ( 1 ) and [Al(O i Pr) 2 O 2 P(O t Bu) 2 ] 4 ( 2 ), respectively. In the solid state, 1 exists as a centrosymmetric dimer consisting of two four-coordinate Al centers bridge…
Poly(dl-lactide) (PLA) homopolymers and poly(dl-lactide-co-glycolide) (PLGA) copolymers were synthesized from their cyclic dimers, i.e. dl-lactide and glycolide, by ring-opening polymerization in the presence of catalyst stannous octoate and chain control agent lauryl alcohol. The effects of catalyst and chain control…
A series of nonionic sugar-based bolaamphiphiles having n -alkylene chain length of 9, 10, 11, 12, 13, 14, 16, or 18 carbon atoms, N,N ‘ -bis(2-deoxy- d -glucopyranosid-2-yl)alkane-1, n -dicarboxamide, 1( n ), have been synthesized in one step from commercially available glucosamine hydrochloride. Their self-assemblin…
Reaction of R 2 dbmH (R = H, Me, Et; dbmH is dibenzoylmethane) with MnCl 3 (generated in situ from MnCl 2 and MnO 4 - ) in MeCN yields the five-coordinate, square-pyramidal complexes [MnCl(R 2 dbm) 2 ] (R = H, 1; Me, 4; Et, 7 ). The same reaction with MnBr 2 yields [MnBr(R 2 dbm) 2 ] (R = H, 2; Me, 5; Et, 8 ). Slow hy…