Structural phase transitions in Zn(CN)2 under high pressures

High pressure behavior of zinc cyanide (Zn(CN)₂) has been investigated with the help of synchrotron-based X-ray diffraction measurements. Our studies reveal that under pressure this compound undergoes phase transformations and the structures of the new phases depend on whether the pressure is hydrostatic or not. Under hydrostatic conditions, Zn(CN)₂ transforms from cubic to orthorhombic to cubic-II to amorphous phases. In contrast, the non-hydrostatic pressure conditions drive the ambient cubic phase to a partially disordered crystalline phase, which eventually evolves to a substantially disordered phase. The final disordered phase in the latter case is distinct from the amorphous phase observed under the hydrostatic pressures.     

Synthesis, spectra, and theoretical investigations of the triarylamines based on 6H-indolo[2,3-b]quinoxaline

Triarylamines containing a 6H-indolo[2,3-b]quinoxaline core and aromatic units such as phenyl, naphthyl, pyrene, anthracene, or fluorene have been synthesized by employing palladium-catalyzed C-N and C-C coupling reactions and characterized by optical absorption and emission spectra, electrochemical behavior, and thermal studies. Even though the electronic absorption spectra of the compounds were influenced by the nature of the peripheral amines, the emission spectra indicated close similarity for the excited states in these compounds. For the derivatives in which the amines were directly anchored on the 6H-indolo[2,3-b]quinoxaline nucleus, the emission appeared to be dominated by the state localized on the 6H-indolo[2,3-b]quinoxaline chromophore, while in the compounds containing the extended conjugation the fluorescence originated from the polyaromatic linker. The compounds displayed green or yellow emission depending on the nature of the amine segment. All of the dyes displayed one-electron quasi-reversible oxidation couple in the cyclic voltammograms, which is attributable to the oxidation of the peripheral amines at the 6H-indolo[2,3-b]quinoxaline core. An additional one-electron oxidation process observable at the high positive potentials for the compounds 7 and 8 probably arises from the oxidation of the arylthiophene segment. The enhanced thermal stability and relatively higher glass transition temperatures observed for these compounds were attributed to the presence of dipolar 6H-indolo[2,3-b]quinoxaline segment. The origin of the optical spectra and the trends observed therein were rationalized using TDDFT simulations.     

Template-based fabrication of Ag–ZnO core–shell nanorod arrays

We report a simple, versatile, two-step fabrication technique for synthesizing a core–shell nanorod array whose architecture is specifically suited for use as an electrode in a dye sensitized solar cell (DSSC). The particular structure fabricated by us consists of a parallel array of 5 μm long and 150–200 nm wide Ag nanorod cores, each coated with a 15–20 nm thick ZnO shell. Importantly, the shell thickness is roughly uniform throughout the length of the rods, which are free standing but distinctly separated from each other. This would allow the dye to penetrate freely and cover the ZnO surface completely in a DSSC.     

Monosaccharide-Directed Selective Internalization of Gold and Silver Nanoparticles in Hepatic Cancer Cells

The therapeutic success of nanomedicines requires nanomaterials to either adhere to the surface or internalize within the cytoplasm. The endocytosis phenomenon is controlled by the nanomaterial's shape, size, composition, charge, and capping molecules. The membrane potential-based non-specific internalization of therapeutic nanomedicines offers limited benefits than receptor-based specific delivery. Glut receptor-based internalization of glucose molecules is a well-known process in cancerous cells, which is one of the most exploited strategies to target cancer cells using nanoparticles. However, the internalization process of other structurally similar monosaccharides (D-Galactose, Mannose, and D-Fructose) conjugated nanoparticles remains to be unexplored. Herein, D-Glucose, D-Galactose, Mannose, and D-Fructose-coated AuNPs and AgNPs have been synthesized and studied the role of Glut receptors in their internalization in liver cancer cells, and compared them with non-cancerous cells. Results revealed that almost all monosaccharide-coated NPs exhibited high uptake in liver cancer cells than non-cancerous cells. Glut-1 receptor is observed to play a key role in the uptake and inhibition of Glut-1 receptors by genistein lead to a significant decrease in nanoparticle uptake. In conclusion, monosaccharide-conjugated nanoparticles can be used to direct the selective internalization of AuNPs and AgNPs in hepatic cancer cells to realize therapeutic and imaging applications.     

Solution combustion synthesis,energy and environment: Best parameters for better materials

Solution combustion synthesis (SCS) is a worldwide used methodology for the preparation of inorganic ceramic and composite materials with controlled properties for a wide number of applications, from catalysis to photocatalysis and electrocatalysis, from heavy metal removal to sensoristics and electronics. The high versatility and efficiency of this technique have led to the introduction of many variants, which allowed important optimization to the prepared materials. Moreover, its ecofriendly nature encouraged further studies about the use of sustainable precursors for the preparation of nanomaterials for energy and environment, according to the concept of circular economy. On the other hand, the large variety of expressions to define SCS and the often-contradictory definitions of the SCS parameters witnessed a scarce consciousness of the potentiality of this methodology. In this review article, the most important findings about SCS and the selection criteria for its main parameters are critically reviewed, in order to give useful guidelines to those scientists who want to use this methodology for preparing materials with improved or new functional properties. This review aims as well (i) to bring more clarity in the SCS terminology (ii) to increase the awareness of the SCS as a convenient tool for the synthesis of materials and (iii) to propose a new perspective in the SCS, with special attention to the use of ecofriendly procedures. Part of the review is also dedicated to precautions and limitations of this powerful methodology.     

A cylindrically symmetric inhomogeneous cosmological model with electromagnetic field

A cylindrically symmetric inhomogeneous cosmological model with electromagnetic field for perfect fluid distributions is obtained. To get a determinate solution, a supplementary conditionA=(BC) ⁿ between metric potentials is used whereA, B, andC are functions of bothx andt andn is a constant. Some physical and geometrical properties of the model and behavior of electromagnetic field tensors are also discussed.     

DABCO: an efficient promoter for the acetylation of carbohydrates and other substances under solvent-free conditions

A simple, mild and efficient solvent-free method for the acetylation of carbohydrates, and their partially protected derivatives, as well as non-carbohydrate substances in excellent yields in the presence of 1,4-diazabicyclo[2.2.2]octane (DABCO) is described with the advantage of tolerance to various functional groups, short reaction time and ease of product isolation.