Accelerating the electron-transfer of nitrogen electro-fixation through assembling Fe nanoparticles into Fe nanochains.

Electrochemically synthesizing NH3 via N2 is a facile and sustainable approach that involves multistep electron and proton transfer processes. Thus, consecutive electron and proton transfer is necessary. Here, a universal method with the assistance of magnetic stirring that can assemble Fe, Co, and Ni nanoparticles into nanochains is developed. Notably, the Fe nanochain, composed of amorphous Fe nanoparticles, facilitates electron and proton transfer, resulting in an enhanced NH3 yield (92.42 µg h-1 mg-1) and faradaic efficiency (20.02%) at -0.4 V vs. RHE during the electrochemical reduction of N2. This work offers new insight into designing tandem electrocatalysts.

Fluoromethoxymethylation of Nitrogen Heterocyclic Compounds with Fluoromethyl Iodide.

The fluoromethoxymethylation of nitrogen heterocyclic compounds with fluoromethyl iodide has been reported for the first time. In this reaction, a number of unexplored fluoromethoxymethylated nitrogen heterocyclic compounds including indoles, carbazoles, and 1H-indazoles were efficiently formed. Mechanistic studies indicated that this transformation consists of electrophilic monofluoromethylation, rapid hydrolysis, and another electrophilic monofluoromethylation. This method makes it possible to synthesize complex bioactive molecules containing a CH2OCH2F group, which have the potential to be a new series of fluorine-containing chemical entities for medicinal chemists.

Trifluoromethanesulfinyl Chloride for Electrophilic Trifluoromethythiolation and Bifunctional Chlorotrifluoromethythiolation.

Trifluoromethanesulfinyl chloride (CF3 SOCl) has been introduced as a new reagent for C-H trifluoromethylthiolation of indoles, thiophenes, and ketones under catalyst-free conditions and in the absence of reductant. The disproportionation of CF3 SOCl to CF3 SO2 Cl and CF3 SCl provides two pathways for the trifluoromethylthiolation. Direct trifluoromethylthiolation with CF3 SCl or trifluoromethylsulfoxidation with CF3 SOCl is followed by reduction with CF3 SOCl. This reagent can be used to functionalize benzothiophenes, benzofurans, and indenes under the promotion of Ag2 CO3 . It can also be used for trifluoromethylthiolation of thiols and benzeneselenols, and 1,2-bifunctional chlorotrifluoromethylthiolation of indoles, styrenes, and alkyenes. The method can also be extended for difluorometylthiolation reactions using CF2 HSOCl.

Metal-Free Electrophilic Trifluoroethylthiolation with NaSO2CH2CF3.

Metal-free trifluoroethylthiolation with fluorinated sulfinate salt NaSO2CH2CF3 under reductive conditions has been developed. The strategy enables the installation of the SCH2CF3 moiety efficiently to form a number of unexplored stable trifluoroethylthiolated heterocycles, arenes, and thiols, which have the potential to be a new series of fluorine-containing chemical entities for medicinal chemists.

Stereoselective Synthesis of Alkenyl Silanes, Sulfones, Phosphine Oxides, and Nitroolefins by Radical C-S Bond Cleavage of Arylalkenyl Sulfides.

A radical-mediated approach has been introduced for the C-S bond activation of arylalkenyl sulfides. The protocol provides an efficient approach for the generation of various alkenes including alkenyl silanes, sulfones, phosphine oxides, and nitroolefins. In most cases, these radical substitutions are performed under metal-free conditions with stereospecificity.

Radical Route to 1,4-Benzothiazine Derivatives from 2-Aminobenzenethiols and Ketones under Transition-Metal-Free Conditions.

Transition-metal-free radical access to 1,4-benzothiazine derivatives from o-aminobenzenethiols is disclosed. This procedure is available for various ketones including α,ß-unsaturated, cyclic, linear, and fluoroalkyl ketones to generate a number of 1,4-benzothiazines, which exist in numerous bioactive and natural molecules, rendering this protocol attractive to both synthetic and medicinal chemistry.

A new receptor model-incremental lifetime cancer risk method to quantify the carcinogenic risks associated with sources of particle-bound polycyclic aromatic hydrocarbons from Chengdu in China.

PM10 and PM2.5 samples were simultaneously collected during a one-year monitoring period in Chengdu. The concentrations of 16 particle-bound polycyclic aromatic hydrocarbons (Σ16PAHs) were measured. Σ16PAHs concentrations varied from 16.85 to 160.24 ng m(-3) and 14.93 to 111.04ngm(-3) for PM10 and PM2.5, respectively. Three receptor models (principal component analysis (PCA), positive matrix factorization (PMF), and Multilinear Engine 2 (ME2)) were applied to investigate the sources and contributions of PAHs. The results obtained from the three receptor models were compared. Diesel emissions, gasoline emissions, and coal and wood combustion were the primary sources. Source apportionment results indicated that these models were able to track the ΣPAHs. For the first time, the cancer risks for each identified source were quantitatively calculated for ingestion and dermal contact routes by combining the incremental lifetime cancer risk (ILCR) values with the estimated source contributions. The results showed that gasoline emissions posed the highest cancer risk, even though it contributed less to Σ16PAHs. The results and method from this work can provide useful information for quantifying the toxicity of source categories and studying human health in the future.