Micelles and reverse micelles in the nickel bis(2-ethylhexyl) sulfosuccinate/water/isooctane microemulsion

The ternary system Ni(2+)(AOT)(2) (nickel 2-bis[2-ethylhexyl] sulfosuccinate)/water/isooctane presents w/o and o/w microemulsions with a Winsor progression (2Phi-3Phi-2Phi), without the addition of salt; the "fish diagram" was obtained for alpha=0.5 and gamma=0.02-0.22. Using static and dynamic light scattering the micellar size, the ratio of water to surfactant, and the density of micelles for this system were estimated. In addition, the mean interfacial curvature as a function of temperature was obtained.     

Fresh Inflation with Nonminimally Coupled Inflaton Field

I study a fresh inflationary model with a scalar field nonminimally coupled to gravity. An example is examined. I find that, as larger is the value of p (a t ^p ), as smaller (but larger in its absolute value) is the necessary value of the coupling to the inflaton field fluctuations can satisfy a scale invariant power spectrum.     

The formation of ReS(2) inorganic fullerene-like structures containing Re(4) parallelogram units and metal-metal bonds

The encapsulation of ReO(x) within ReS(2) inorganic fullerene-like cages is described for the first time. The encapsulate was prepared by the sulfidization of both hand-milled and ball-milled samples of ReO(2); partial conversion of the oxide to the sulfide was achieved with the degree of sulfidization depending on the exposure to the sulfidizing agent, H(2)S.     

LETTER: BTZ Black Hole from (3+1) Gravity

We propose an approach for constructing spatial slices of (3+1) spacetimes with cosmological constant but without a matter content, which yields (2+1) vacuum with solutions. The reduction mechanism from (3+1) to (2+1) gravity is supported on a criterion in which the Weyl tensor components are required to vanish together with a dimensional reduction via an appropriate foliation. By using an adequate reduction mechanism from the Plebaski–Carter[A] solution in (3+1) gravity, the (2+1) BTZ solution can be obtained.     

Warm Inflation and Scalar Perturbations of the Metric

A second-order expansion for the quantum fluctuations of the matter field was considered in the framework of the warm inflation scenario. The friction and Hubble parameters were expanded by means of a semiclassical approach. The fluctuations of the Hubble parameter generates fluctuations of the metric. These metric fluctuations produce an effective term of curvature. The power spectrum for the metric fluctuations can be calculated on the infrared sector.     

Bifurcating reactions: distribution of products from energy distribution in a shared reactive mode

Bifurcating reactions yield two different products emerging from one single transition state and are therefore archetypal examples of reactions that cannot be described within the framework of the traditional Eyring''s transition state theory (TST). With the growing number and importance of these reactions in organic and biosynthetic chemistry, there is also an increasing demand for a theoretical tool that would allow for the accurate quantification of reaction outcome at low cost. Here, we introduce such an approach that fulfils these criteria, by evaluating bifurcation selectivity through the energy distribution within the reactive mode of the key transition state. The presented method yields an excellent agreement with experimentally reported product ratios and predicts the correct selectivity for 89% of nearly 50 various cases, covering pericyclic reactions, rearrangements, fragmentations and metal-catalyzed processes as well as a series of trifurcating reactions. With 71% of product ratios determined within the error of less than 20%, we also found that the methodology outperforms three other tested protocols introduced recently in the literature. Given its predictive power, the procedure makes reaction design feasible even in the presence of complex non-TST chemical steps.

Reactive Mode Composition Factor (RMCF) analysis is a powerful tool to forecast the product distribution of bifurcating reactions through analysis of the kinetic energy distribution within the first transition state traversed by the reacting system.     

Exploring the nitro group reduction in low-solubility oligo-phenylenevinylene systems: Rapid synthesis of amino derivatives

Abstract

A small series of amino oligo-phenylenevinylenes (OPVs) were successfully synthesized from their nitro-analogs in a rapid, simple, and highly efficient fashion employing a sodium sulfide/pyridine system as a reducing agent. In this research, classic and sustainable reduction methodologies including NH₄HCO₂/Zn and a choline chloride/tin (II) chloride deep eutectic solvent (DES) were also evaluated, showing degradation products, incomplete reactivity, and product isolation difficulties in all cases. The straightforward Na₂S/pyridine synthetic protocol proved to maintain the E-E stereochemistry of the OPV backbone that has been previously assembled by the Mizoroki–Heck cross-coupling reaction. Also, the optoelectronic properties were determined and discussed, considering the amino group insertion in these conjugated systems as a contribution for future construction of novel materials with applications in supramolecular electronics, light harvesting, and photocatalysis.     

Synthesis and characterization of materials prepared via the copolymerization of ethylene with 1‐octadecene and norbornene using a [(π‐cyano‐nacnac)Cp] zirconium complex

[3‐Cyano‐2‐(2,6‐diisopropylphenyl)aminopent‐2‐en‐4‐(phenylimine)tris (pentafluorophenyl)borate](η⁵‐C₅H₅)ZrCl₂, [(B(C₆F₅)₃‐ NC‐nacnac)CpZrCl₂], precatalyst ( 2 ) can be treated with low concentrations of methylaluminoxane (MAO) to generate active sites capable of copolymerizing ethylene with 1‐octadecene or norbornene under mild conditions. A series of poly(ethylene‐co‐octadecene) and poly(ethylene‐co‐norbornene) copolymers were prepared, and their properties were characterized by NMR, differential scanning calorimetry, and mechanical analysis. The results show that this system produced poly(ethylene‐co‐octadecene) copolymers with a branching content of about 8 mol %. However, upon increasing the comonomer concentration, a drastic reduction in the M_n of the product is observed concomitant with an increase in comonomer incorporation. This leads to a gradual decrease in Young's modulus and stress at break, indicating an increase in the “softness” of the copolymer. In the case of copolymerizations of ethylene and norbornene, the catalytic system ( 2 /MAO) shows a substantial decrease in reactivity in the presence of norbornene and generates copolymer chains in which 5–10 mol % norbornene is in blocks. We also observe that ethylene norbornene copolymers exhibit a high degree of alternating insertions (close to 50%), as determined by NMR spectroscopy. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011