Ferric nitrate in the presence of catalytic amounts of KBr or NaBr: an efficient and homoselective catalytic media for the selective oxidation of sulfides to sulfoxides

Catalytic Application of Biochar Functionalized Copper-l-histidine for the Chemo and Homoselective Conversion of Cyanides to Amides and Reduction of Nitroarenes to anilines

In our study, we aimed to use olive pomace, food industry waste, as biomass to produce biochar nanoparticles. The surface of the biochar was functionalized with the l-histidine ligand, and then cupric acetate was added to prepare Cu-l-histidine@biochar as a final catalyst for the chemo- and homoselective synthesis of amide and aniline derivatives. To characterize the novel catalyst, we employed various techniques. Another notable feature of this catalyst is its reusability, which maintained significant efficiency even after multiple uses in reactions.

The Properties, Synthesis, and Materials Applications of 1,4-Dithiins and Thianthrenes

1,4-Dithiin and its dibenzo-analogue, thianthrene, represent a class of non-aromatic, sulfur-rich heterocycles. Their unique properties, stemming from both their non-planar structures and reversible one- and two-electron oxidations, serve as primary motivators for their use in the development of new materials. The applications of 1,4-dithiins and thianthrenes are rich and diverse, having been used for energy storage and harvesting, and the synthesis of phosphorescent compounds and porous polymers, among other uses. This review offers first an overview of the properties of 1,4-dithiin and thianthrene. Next, we describe enabling synthetic methodology to access 1,4-dithiins and thianthrenes with various substitution patterns. Lastly, the utility of 1,4-dithiin and thianthrene in the construction and design of new materials is detailed using select literature examples.

1 Introduction

2 Properties of 1,4-Dithiins and Thianthrenes

3 Synthesis of 1,4-Dithiins and Thianthrenes

3.1 Synthesis of 1,4-Dithiins

3.2 Synthesis of Thianthrenes

4 Application of 1,4-Dithiins and Thianthrenes in Materials

4.1 Thianthrene-Containing Polymers

4.2 Thianthrene in Redox-Active Materials

4.3 Thianthrenes and 1,4-Dithiins in Supramolecular Chemistry and Self-Assembly

4.4 Thianthrenes in Phosphorescent Materials

4.5 Thianthrenes with Other Interesting Photophysical Properties

4.6 Thianthrenes in the Synthesis of Non-natural Products

5 Conclusion

Catalytic reaction system for rapid selective oxidation of alkyl sulphide

Highly efficient catalytic reaction systems are developed to rapidly and selectively oxidize 2-chloroethyl ethyl sulfide (CEES). In the systems, precursors containing bromide(s) and nitrate anions are chosen for the development of cyclic catalytic loop and the effect of acids on the selective oxidation of CEES are investigated by the addition of several homogeneous acid catalysts. The experimental results reveal that addition of acid results in a higher concentration of tribromide, which is reported as a key component for the observed activity in the catalytic solution. As a consequence, a dramatic improvement in catalytic activity is observed, especially when the molar amount of acid is controlled to be more than twice the initial concentration of tribromide. For the efficient design of a catalytic system, heterogeneous acid catalysts possessing different ratios of Brønsted to Lewis acid sites are also considered. Compared to reaction systems catalysed by homogeneous acids, similar reaction behaviour is observed for the reaction with Amerlyst-15, while those with other heterogeneous catalysts, containing Lewis or mixed acid sites in their structure, exhibits an adverse effect of selective sulfoxidation, mainly due to the adsorption of anions onto Lewis sites and consequential deconstruction of the catalytic loop.

Mechanistic reaction model for oxidation of sulfur mustard simulant by a catalytic system of nitrate and tribromide

A new metal-free catalytic reaction system is developed to selectively oxidize 2-chloroethyl ethyl sulfide (CEES), a surrogate of sulfur mustard. The combination of two catalytic precursors, tribromide and nitrate, allows a rapid sulfoxidation of CEES even at ambient conditions. The kinetic behaviours at various reaction conditions are investigated to identify the most probable reaction pathways of the development of catalytic loop and the overall reaction steps of CEES sulfoxidation. The mechanistic study demonstrates that the catalytic loop does not require an addition of mineral acid or water, which is common in most other reaction systems. Incomplete catalytic systems with one precursor are also examined to uncover the complex network of sulfoxidation in the catalytic reaction system. The results reveal that the complex between CEES and bromine is a reactive intermediate, bromosulfonium, which can be further catalysed and converted into sulfoxide by nitrate. Based on the proposed reaction mechanism, a predictive kinetic model fully describing most reaction behaviours is developed.