Materials Literature
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Hydroxy-terminated poly(2,2-substituted-1,3-propylene oxide) telechelics and co-telechelics bearing semifluorinated (R = -CH(2)OCH(2)(CF(2))(n)CF(3), n = 0, 1) and/or bromomethyl pendant groups were synthesized from the corresponding 3,3-substituted oxetanes. The new telechelics were incorporated in polyurethanes (PUs…
In recent work, it was shown that V-containing polyoxometalates such as (n-Bu4N)7SiW9V3O40 or (n-Bu4N)9P2W15V3O62, as well as eight other V-containing precatalysts tested, evolve to a high activity, long catalytic lifetime (> or = 30,000-100,000 total turnovers) 3,5-di-tert-butylcatechol dioxygenase, in which Pierpont…
[reaction: see text] Bimetallic alkylzinc calixarene inclusion complexes were prepared and used in the ring-opening polymerization of L-lactide. Polymers with high molecular weight and a low degree of polydispersity were obtained. 1H NMR and diffusion NMR experiments suggest that a single-site mechanism is operative.
Abstract We found that the cationic polysaccharide chitosan is an efficient dispersion agent for single-walled carbon nanotubes (SWNTs). The spectroscopic properties of chitosan–SWNTs dispersion are different from sodium dodecyl sulfate (SDS)–SWNTs dispersion in acidic conditions. It has been revealed that chitosan is…
The one-electron reduction of [alpha(2)-Fe(III)(OH(2))P(2)W(17)O(61)](7-) at a glassy carbon electrode was investigated using cyclic and rotating-disk-electrode voltammetry in buffered and unbuffered aqueous solutions over the pH range 3.45-7.50 with an ionic strength of approximately 0.6 M maintained. The behavior is…
The preparation of 2,6-azulenedicarboxylic acid (I) from its diester, 2-CO(2)(t)Bu-6-CO(2)-C(10)H(6) (II), is reported together with the crystal and molecular structure of the ester, II. From the reactions between the dicarboxylic acid I and the MM quadruply bonded complexes M(2)(O(2)C(t)Bu)(4), where M = Mo or W, the…
[Reaction: see text]. Sodium chlorite has been demonstrated to be capable of epoxidizing a variety of olefins at 55-65 degrees C (oil bath). Chlorine dioxide is believed to be the pivotal epoxidizing agent in the reaction on the basis of the mechanistic studies.
Core−shell nanoparticles with a polystyrene core and a hybrid copolymer shell are synthesized via emulsion polymerization of styrene and subsequent addition of γ-methacryloyloxypropyltrimethoxysilane (MPS) to produce the shell by copolymerization reaction of MPS with the residual amount of styrene. The kinetics of cop…
We present a unified model for complete crystal-growth inhibition based on the thermodynamics of interfaces. The premise for our model is that the adsorption of inhibitor leads to a reduction in interfacial tension or edge energy for the crystal surface or step, respectively. In our formulation, the work to add a laye…
We present the first implementation of the quadratic response function for multiconfigurational self-consistent-field wave functions of solvated molecules described by a polarizable continuum model employing a molecule-shaped cavity. We apply the methodology to the first hyperpolarizability beta and, in particular, th…
A simple method for growing polymer brushes by atom transfer radical polymerization (ATRP) off solid surfaces has been devised. This entails pulsed plasmachemical deposition of a halogen-containing initiator layer, followed by either organic or aqueous phase controlled surface polymerization. The wide-scale applicabil…
Surface-enhanced Raman scattering or SERS, discovered some 20 years ago, has recently become a promising tool for routine biofluid assays in a clinical setting. Many attempts have been made to produce cheap and reproducible SERS-active substrates. In this study, we report on the fabrication of SERS-active substrates t…
Isochorismate pyruvate lyase (IPL) catalyzes the cleavage of isochorismate to give salicylate and pyruvate, a key step in bacterial siderophore biosynthesis. We investigated the enzyme from Pseudomonas aeruginosa using isochorismate selectively deuterated at C2 as a substrate. Monitoring the reaction by 2H NMR spectro…
Surface-enhanced Raman spectroscopy (SERS) substrates have been prepared by depositing Au or Ag on porous GaN (PGaN). The PGaN used as the template for the metal deposition in these studies was generated by a Pt-assisted electroless etching technique. PGaN was chosen as a potential SERS template due to its nanostructu…
Highly isotactic polypropylene samples, containing a very low amount of rr stereodefects (0.1−0.2%) and slightly higher concentration of defects of regioregularity (0.8−0.9% of 2,1 erythro units), with different molecular masses have been prepared with an isospecific but not fully regioselective metallocene catalyst.…
A joint theoretical and experimental study of the electronic and structural properties of liquid crystalline metal-free phthalocyanines bearing a strong potential for charge and exciton transport has been performed. The synthesis of such compounds has been triggered by quantum chemical calculations showing that: (i) h…
Major ampullate silk, also known as dragline silk, is one of the strongest biomaterials known. This silk is composed of two proteins, major ampullate spidroin 1 (MaSp1) and major ampullate spidroin 2 (MaSp2). Only partial cDNA sequences have been obtained for these proteins, and these sequences are toward the C-termin…
The coupling between electrons and phonons plays important roles in physics, chemistry and biology. However, the accurate calculation of the electron-phonon coupling constants is computationally expensive as it involves solving the Schrodinger equation for O(N) nuclear configurations, where N is the number of nuclei.…
Reversible addition−fragmentation chain transfer polymerization was applied to the synthesis of well-defined diblock glycopolymers carrying different cyclic carbohydrates on the two blocks. The macroRAFT agents poly(methyl 6- O -methacryloyl-α- d -glucoside) dithiobenzoate and poly(2-methacryloxyethyl glucoside) dithi…
Pyrochlore-type yttrium stannate (Y 2 Sn 2 O 7 ) doped with trivalent europium ions (Eu 3+ ) was synthesized as thin films by the sol−gel method. X-ray diffractometry, high-resolution transmission electron microscopy, and X-ray photoelectron spectroscopy were used to evaluate the crystallinity and purity of the films,…