Sulfur 8% / Resorcinol 2% cream

Lithium-sulfur batteries (LSBs), possessing excellent theoretical capacities, advanced theoretical energy densities, low cost, and nontoxicity, are one of the most promising energy storage battery systems. However, some issues, including poor conductivity of elemental S, the "shuttle effect" of high-order lithium polysulfides (LiPSs), and sluggish reaction kinetics, hinder the commercialization of LSBs. To solve these problems, various carbon-based aerogels with developed surface morphology, tunable pores, and electrical conductivity have been examined for immobilizing sulfur, mitigating its volume variation and enhancing its electrochemical kinetics. In this paper, an extensive generalization about the effective preparation methods of carbon-based aerogels comprising the combined method of carbonization with the gelation of precursors and drying processes (ambient pressure drying, freeze-drying, and supercritical drying) is proposed. And we summarize various carbon carbon-based aerogels, mainly including graphene aerogels (Gas) and carbon nanofiber (CNF) and carbon nanotube (CNT) aerogels as cathodes, separators, and interlayers in LSBs. In addition, the mechanism of action of carbon-based aerogels in LSBs is described. Finally, we conclude with an outlook section to provide some insights into the application of carbon-based aerogels in electrochemical energy storage devices. Based on the discussion and proposed recommendations, we provide more approaches on nanomaterials in high-performance liquid or state LSBs with high electrochemical performance in the future.

Abstract licence: CC BY

Tyrosinases (TYRs) are copper-containing metalloenzymes present in a large diversity of species. In human, hTYR is responsible for pivotal steps in melanogenesis, catalysing the oxidation of l-tyrosine to l-DOPA and further to dopaquinone. While numerous TYR inhibitors have been reported, polyphenolic compounds tend to dominate the literature. However, many of these compounds, particularly monophenols and catechols, have been identified as alternative substrates rather than true inhibitors, given their structural similarity to natural substrates. Resorcinol-containing compounds have emerged as promising candidates to address this challenge, as the meta-dihydroxy moiety in resorcinol demonstrates resistance to TYR-mediated oxidation, while retaining the favourable interactions with copper ions provided by the hydroxy groups. Although their precise mechanism of action remains debated, resorcinol derivatives have yielded some of the most active compounds against isolated mushroom and human TYRs, as well as clinically used dermocosmetic agents like rucinol and thiamidol, which exhibited very promising effects in patients with facial melasma. This review outlines the development of resorcinol-containing TYR inhibitors, categorized by scaffold type, ranging from simple alkyl analogues to intricate synthetic derivatives. Mechanistic insights about the resorcinol-TYR interaction are also presented and debated.

Abstract licence: CC BY

This research presents an innovative approach for synthesizing 2-amino-4H-chromene derivatives, utilizing 30 mg of NS-doped graphene oxide quantum dots (GOQDs) as a catalyst in a one-pot, three-component reaction conducted in ethanol. The NS-doped GOQDs were synthesized using a cost-effective bottom-up method through the condensation of citric acid (CA) with thiourea and the reaction was carried out at 185 $$^{\circ }$$ C, resulting in the elimination of water. The catalytic performance of the synthesized NS-doped GOQDs resulted in high product yields, achieving up to 98% for the 2-amino-4H-chromene derivatives from aromatic aldehydes, malononitrile, resorcinol, $$\beta$$ -naphthol, and dimedone. The reaction showcased rapid completion time (typically < 2 h), low-cost reagents, and easy work-up procedures. In addition, the study integrates experimental and theoretical analyses, including density functional theory (DFT) calculations, to investigate the electronic properties of the synthesized compounds. Calculated HOMO and LUMO energies indicate efficient charge transfer within the molecular structure. The FT-IR spectra of compound 4c were recorded in the range of 4000–500 cm $${^{-1}}$$ , and vibrational frequencies were computed at the B3LYP/6-311+G(d,p) level, correlating well with experimental data. Detailed analyses, including Mep surfaces, Mulliken population analysis, and Natural Bond Orbital (NBO) analysis, provide further insights into the electronic distribution and reactivity of the compounds. Furthermore, comparative $${^1}$$ H and $${^{13}}$$ C NMR analyses of compound 4c reveal strong agreement between computational and experimental findings. This research not only validates the synthetic method but also emphasizes the dual experimental and computational approach in understanding the structural and electronic characteristics of the 4c compound.

Abstract licence: CC BY-NC-ND