A strategy to avoid solid formation within the reactor during magnesium and calcium electrolytic removal from lithium-rich brines

Journal of Solid State Electrochemistry - It is expected that lithium sourcing from aqueous sources in the medium term will account for over half of worldwide production, since reserves in brines...     

Control of electron excitation and localization in the dissociation of H2(+) and its isotopes using two sequential ultrashort laser pulses

We study the control of dissociation of the hydrogen molecular ion and its isotopes exposed to two ultrashort laser pulses by solving the time-dependent Schr?dinger equation. While the first ultraviolet pulse is used to excite the electron wave packet on the dissociative 2psigma{u} state, a second time-delayed near-infrared pulse steers the electron between the nuclei. Our results show that by adjusting the time delay between the pulses and the carrier-envelope phase of the near-infrared pulse, a high degree of control over the electron localization on one of the dissociating nuclei can be achieved (in about 85% of all fragmentation events). The results demonstrate that current (sub-)femtosecond technology can provide a control over both electron excitation and localization in the fragmentation of molecules.     

Towards Bioprospection of Commercial Materials of Mentha spicata L. Using a Combined Strategy of Metabolomics and Biological Activity Analyses

Spearmint (Mentha spicata L.) has been widely studied for its diversity of compounds for product generation. However, studies describing the chemical and biological characteristics of commercial spearmint materials from different origins are scarce. For this reason, this research aimed to bioprospecting spearmint from three origins: Colombia (Col), Mexico (Mex), and Egypt (Eg). We performed a biological activity analysis, such as FRAP, DPPH, and ABTS, inhibition potential of S. pyogenes, K. pneumoniae, E. coli, P. aeuroginosa, S. aureus, S aureus Methicillin-Resistant, and E. faecalis. Furthermore, we performed chemical assays, such as total polyphenol and rosmarinic acid, and untargeted metabolomics via HPLC-MS/MS. Finally, we developed a causality analysis to integrate biological activities with chemical analyses. We found significant differences between the samples for the total polyphenol and rosmarinic acid contents, FRAP, and inhibition analyses for Methicillin-Resistant S. aureus and E. faecalis. Also, clear metabolic differentiation was observed among the three commercial materials evaluated. These results allow us to propose data-driven uses for the three spearmint materials available in current markets.     

Electrophilic Chlorine from Chlorosulfonium Salts: A Highly Chemoselective Reduction of Sulfoxides

Herein, we describe a selective late-stage deoxygenation of sulfoxides based on a novel application of chlorosulfonium salts and demonstrate a new process using these species generated in situ from sulfoxides as the source of electrophilic chlorine. The use of highly nucleophilic 1,3,5-trimethoxybenzene (TMB) as the reducing agent is described for the first time and applied in the deoxygenation of simple and functionalized sulfoxides. The method is easy to handle, economic, suitable for gram-scale operations, and readily applied for poly-functionalized molecules, as demonstrated with more than 45 examples, including commercial medicines and analogues. We also report the results of competition experiments that define the more reactive sulfoxide and we present a mechanistic proposal based on substrate and product observations.     

Crystal and Molecular Structures of Two Triazole Derivatives: 4-Cyclopropyl-4,5-dihydro-1H-1,2,3-triazole and Methyl 1-benzyl-1H-1,2,3-triazole-4-carboxylate

Abstract  

The molecule in 4-cyclopropyl-4,5-dihydro-1H-1,2,3-triazole (I) is disposed about a mirror plane with the triazole ring lying in the plane and being orthogonal to the cyclopropyl ring. Considerable delocalization of π-electron density within the triazole ring is indicated by the pattern of bond distances in (I). The molecule of methyl 1-benzyl-1H-1,2,3-triazole-4-carboxylate (II) adopts a curved shape with the dihedral angle formed between the triazole and benzene rings being 63.23(8)°. By contrast to (I), localization of π-electron density within the triazole ring in (II) is indicated. Both (I), via N–H···N hydrogen bonding, and (II), via C–H···O and C–H···N interactions, associate in the solid state to form supramolecular chains. In (I), the chain is a zigzag with a flat topology, whereas in (II) the linear chain has a curved topology. Compound (I) crystallizes in the orthorhombic space group Pnma with a = 5.6470(2) ?, b = 7.3359(4) ?, c = 13.4404(7) ?, and Z = 4. Compound (II) crystallizes in the monoclinic space group P2₁/c with a = 12.1314(5) ?, b = 5.5951(2) ?, c = 16.4339(7) ?, β = 111.269(2)°, and Z = 4.     

Combined bactericidal activity of silver nanoparticles and hexadecylpyridinium salicylate ionic liquid

Recently, ionic liquids have been used as dispersing agents for silver nanoparticle (AgNP) preparation. In this paper, we have shown a simple method to prepare AgNP in aqueous media using an ionic liquid called hexadecylpyridinium salicylate (HDPSal) as dispersing agent. The dispersions were produced by the chemical reduction of silver ions in aqueous media with different concentrations of HDPSal and tetrabutylammonium borohydride as reducing agent. The UV–Visible electronic spectra showed the characteristic plasmonic resonance band around 420 nm, confirming the formation of AgNPs. The TEM images confirmed the formation of spherical particles with diameters lower than 10 nm. The charge of these particles was determined by Zeta potential and they were around +50 mV, indicating that the HDP cations are surrounding the AgNPs, avoiding their agglomeration. Most of the dispersions remained stable for at least 1 month. Microbiological assays showed that the combination of AgNP with HDPSal results in wider range of antimicrobial effect.