Tin sulfide nanoparticles supported on activated carbon as an efficient and reusable Lewis acid catalyst for three-component one-pot synthesis of 4H-pyrano[2,3-c]pyrazole derivatives

Tin sulfide nanoparticles (SnS‐NPs) were prepared in aqueous solution at room temperature on the surface of activated carbon (AC) and were investigated using field‐emission scanning electron mi‐croscop...     

Ion-pair immobilization of l-prolinate anion onto cationic polymer support and a study of its catalytic activity as an efficient heterogeneous catalyst for the synthesis of 2-amino-4H-chromene derivatives

Research on Chemical Intermediates - A novel clean and simple technique for the heterogenization of l-proline organocatalyst has been introduced. This procedure is based on non-covalent...     

Electronic Raman scattering in double semi-parabolic quantum wells

The differential cross-section for electronic Raman scattering in double semi-parabolic quantum wells of typical GaAs/AlxGa1-x As is investigated numerically with the effective-mass approximation. The dependence of the differential cross-section on structural parameters such as the barrier width and the well widths is studied. Our results indicate that the electronic Raman scattering is affected by the geometrical size and can be negligible in the symmetric double-well case.     

Generation of stable complex gradients across two-dimensional surfaces and three-dimensional gels

Many chemical and biological processes are dependent on molecular gradients. We describe a new microfluidic approach that can be used to produce spatiotemporal gradients across two-dimensional surfaces and three-dimensional gels under flow-free conditions. Free diffusion between dynamically replenished flow channels acting as a sink and source is utilized to give rise to stable steady-state gradient profiles. The gradient profile is dictated by the engineered design of the device's gradient-generating region. Different designs can yield both linear and non-linear gradients of varying profiles. More complex gradients can be made by juxtaposing different designs within a single gradient-generating region. By fabricating an array of designs along the gradient-generating region, different gradient profiles can be generated simultaneously, allowing for parallel analysis. Additionally, simple methods of localizing gels into microdevices are demonstrated. The device was characterized by experimentally obtained gradient profiles of fluorescent molecules that corroborated closely with a simulated finite element model.     

Diatomic dications and dianions

Diatomic dications and dianions are attractive species for quantum chemists and spectroscopists. In comparison with neutral diatomics, these species show a wealth of potential behaviors arising mainly from the presence of residual Coulomb repulsion at the separated ions limit. Due to the stability of dications, numerous reports have been published on their potential curves, vibrational states, stability, and spectroscopic properties. In contrast, there are only a few reports on the stability and potential curves of dianions, since the strong correlation effects in dianions introduce some difficulties in the calculations of their potentials and properties, and perhaps, because they have not been observed in the laboratory due to their short lifetimes. In this review article, interesting subjects related to dications and dianions, the methods used to study their characteristics, and the achievements of these studies are described. Furthermore, the present research topics open on dications and dianions are reviewed. This report would thus serve researchers interested in the examination of quantum dynamical treatment on reactive scattering of ions and the laser–matter interactions and their subsequent phenomena such as vibrational wavepacket evolution, tunneling dissociation, vibronic coupling, and tunneling ionization for which dianions and dications can be regarded as prototypical species.     

Assessment of the effect of N-oxide group in a new high-performance energetic tetrazine derivative on its physicochemical and thermodynamic properties,sensitivity, and combustion and detonation performance

Chemistry of Heterocyclic Compounds - This work uses density functional theory and suitable predictive methods to assess the effect of N-oxide group in 1,2-bis(6-nitro-1,2,4,5-tetrazin-3-yl)diazene...     

The Importance of Precursors and Modification Groups of Aerogels in CO2 Capture

The rapid growth of CO₂ emissions in the atmosphere has attracted great attention due to the influence of the greenhouse effect. Aerogels’ application for capturing CO₂ is quite promising owing to their numerous advantages, such as high porosity (~95%); these are predominantly mesoporous (20–50 nm) materials with very high surface area (>800 m²∙g⁻¹). To increase the CO₂ level of aerogels’ uptake capacity and selectivity, active materials have been investigated, such as potassium carbonate, K₂CO₃, amines, and ionic-liquid amino-acid moieties loaded onto the surface of aerogels. The flexibility of the composition and surface chemistry of aerogels can be modified intentionally—indeed, manipulated—for CO₂ capture. Up to now, most research has focused mainly on the synthesis of amine-modified silica aerogels and the evaluation of their CO₂-sorption properties. However, there is no comprehensive study focusing on the effect of different types of aerogels and modification groups on the adsorption of CO₂. In this review, we present, in broad terms, the use of different precursors, as well as modification of synthesis parameters. The present review aims to consider which kind of precursors and modification groups can serve as potentially attractive molecular-design characteristics in promising materials for capturing CO₂.     

Correlation between Shock Sensitivity of Nitramine Energetic Compounds based on Small‐scale Gap Test and Their Electric Spark Sensitivity

Electric spark sensitivity and shock sensitivity based small‐scale gap test for nitramine energetic compounds are two important sensitivity parameters, which are needed for assessment of their safety in working places. A novel method is introduced for reliable prediction of electric spark or shock sensitivity of a desired nitramine energetic compound when reliable data for one of the sensitivity is available. A novel correlation with a high value of correlation coefficient (R² = 0.998) is derived between electric spark and shock sensitivities of 20 cyclic and acyclic nitramines. For these nitramines, the predicted results of electric spark sensitivities of the novel model are compared with two of the best available models. The root‐mean‐square (rms) and maximum deviations of the new model are 0.20 and 0.51 J, respectively, which are much less than two comparative methods. The reliability of the new method for prediction of electric spark sensitivity of further 14 nitramines is also compared with one of the best available methods, where the measured electric spark or shock sensitivities were not available in literature.