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Synthesis of organochalcogen-modified silver nanoparticles (A1-7), their cytotoxic potentials against glioma cells (C6) & their interaction with DNA.

Selenylated indoles increased the motion rate of the polar region of lipids and ordered the non-polar region, presenting DNA cleavage ability.

We report an efficient and practical procedure for the synthesis of cholesterol containing unsymmetrical liquid crystals dimers. Liquid crystalline and thermal properties were studied by POM, TGA, DSC, and SAXS analysis. All final products (3a-d) presented liquid crystal properties. The presence of smectic (compounds 3a, 3b, and 3d) and chiral nematic (3 c) mesophases evidenced by polarised optical microscopy (POM) and further confirmed by small-angle X-ray scattering (SAXS) analyses. The compound 3 c remains supercooled until room temperature and presented enantiotropic mesomorphism at a low temperature. This characteristic of organisation and mesomorphism at room temperature makes compound 3 c an ideal candidate for technological applications. The SAXS analyses further suggest possibly the presence of smectic clusters within the nematic liquid crystalline phase. All compounds presented high thermal stability at around 300°C when tested for their thermal properties. The highest occupied molecular orbital (HOMO) energies were estimated from cyclic voltammetry (CV) and used together with the optical absorption measurements to determine the band gap and lowest unoccupied molecular orbital (LUMO) energies. The values obtained were: HOMO (–5.81 to – 6.03 eV), LUMO (–1.53 to – 2.12 eV), and band gap (3.88 to 4.28 eV).

This study includes a new protocol for the synthesis of primary and secondary β-chalcogen amines (Se, Te and S) from the ring-opening reaction of non-activated 2-oxazolidinones with chalcogenolate anions.

Pyrite (FeS2) is one of the main tailings derived from coal mining. When processed, pyrite has several applications with high value-added, in contrast, if improperly discarded, it causes major environmental impacts, like the acid mine drainage. For those reasons, the seeking for beneficiation techniques of Pyrite has been the target of numerous studies. One of the most employed techniques is the separation by density using heavy liquids, like bromoform, as a separation medium. In the present work, we propose the use of lithium heteropolytungstate (LST), a non-halogenated and non-toxic solution, as an alternative in the separation by density method. For the experiments, raw pyrite samples were collected from the tailings of coal extraction from a mining company in Santa Catarina, Brazil. After the separation process, the samples before and after the beneficiation were characterized by XRD, FTIR, and XRF techniques. The results revealed that the separation technique used in this work led to a significant increase in the concentration of pyrite, going from less than 10% in the raw sample and reaching almost 80% after processing. This impressive result reveals that LST represents a promising alternative for separating pyrite by density techniques, showing much greater effectiveness than other heavy liquids used in the literature, in addition to being environmentally friendly.