Electrosynthesis of 1,4-bis(diphenylphosphanyl) tetrasulfide via sulfur radical addition as cathode material for rechargeable lithium battery

Organic electrodes are promising as next generation energy storage materials originating from their enormous chemical diversity and electrochemical specificity. Although organic synthesis methods have been extended to a broad range, facile and selective methods are still needed to expose the corners of chemical space. Herein, we report the organopolysulfide, 1,4-bis(diphenylphosphanyl)tetrasulfide, which is synthesized by electrochemical oxidation of diphenyl dithiophosphinic acid featuring the cleavage of a P–S single bond and a sulfur radical addition reaction. Density functional theory proves that the external electric field triggers the intramolecular rearrangement of diphenyl dithiophosphinic acid through dehydrogenation and sulfur migration along the P–S bond axis. Impressively, the Li/bis(diphenylphosphanyl)tetrasulfide cell exhibits the high discharge voltage of 2.9 V and stable cycling performance of 500 cycles with the capacity retention of 74.8%. Detailed characterizations confirm the reversible lithiation/delithiation process. This work demonstrates that electrochemical synthesis offers the approach for the preparation of advanced functional materials.

Vanadium, Niobium and Tantalum Complexes with Terminal Sulfur Radical Ligands

The sulfur radical terminally bound to the metal center can be considered as a one-electron reduction product of the complex with terminal sulfido ligand which serves as the reactive sites...

SARS-CoV-2 ARDS by NLRP3 & ICU Treatment

4,4′-Diaminodiphenyl sulfone (Dapsone, DDS) targets COVID-19 as a key to ending the current ARDS by SARS-CoV-2. Dapsone is an inflammasome competitor commonly used in combination with clofazimine-rifampicin for the treatment of leprosy. Dapsone binds to myeloperoxidase and regulates hypochlorite production, thereby reducing the inflammatory response of cells and has a structure that can reduce the sulfur radical production rate by electron charge transfer because they are structurally similar to methionine sulfoxide. Nucleophilic properties of dapsone compete with ubiquitin by attacking a ubiquitin (Ub)-conjugating enzyme (E2)–Ub thioester linkage. The best-described sites are the amine-containing internal lysine residues and the free amine of the polypeptide backbone’s N-terminus. ORF8b activates NLRP3 through direct interaction of the AT-rich repeat domain of NLRP3. Nucleophilic properties of DDS compete with NLRP3. Dapsone’s four mechanisms have treated ARDS and prevented SARS-CoV-2 infection.

Photocatalytic Oxidative C–H Thiolation: Synthesis of Benzothiazoles and Sulfenylated Indoles

We report studies on the photocatalytic formation of C–S bonds to form benzothiazoles via an intramolecular cyclization and sulfenylated indoles via an intermolecular reaction. Cyclic voltammetry (CV) and density functional theory studies suggest that benzothiazole formation proceeds via a mechanism that involves an electrophilic sulfur radical, while the indole sulfenylation likely proceeds via a nucleophilic sulfur radical adding into a radical cationic indole. These conditions were successfully extended to several thiobenzamides and indole substrates.

Sulfur radical species form gold deposits on Earth

Current models of the formation and distribution of gold deposits on Earth are based on the long-standing paradigm that hydrogen sulfide and chloride are the ligands responsible for gold mobilization and precipitation by fluids across the lithosphere. Here we challenge this view by demonstrating, using in situ X-ray absorption spectroscopy and solubility measurements, coupled with molecular dynamics and thermodynamic simulations, that sulfur radical species, such as the trisulfur ion S3−, form very stable and soluble complexes with Au+ in aqueous solution at elevated temperatures (>250 °C) and pressures (>100 bar). These species enable extraction, transport, and focused precipitation of gold by sulfur-rich fluids 10–100 times more efficiently than sulfide and chloride only. As a result, S3− exerts an important control on the source, concentration, and distribution of gold in its major economic deposits from magmatic, hydrothermal, and metamorphic settings. The growth and decay of S3− during the fluid generation and evolution is one of the key factors that determine the fate of gold in the lithosphere.