Reactivity of aryl chlorides with sodium sulfide in the synthesis of aromatic polyamidethioethers

The synthesis of aromatic copolyamidethioethers by reaction of dichlorobenzanilides with Na₂S has been studied. The reactivity of chlorine atoms is strongly dependent on the nature of the substituent in para position. It is related to the ¹³C NMR shifts of the relative carbons-the more deshielded, the more reactive-and hence to charge densities, agreing with aromatic nucleophilic substitution mechanisms. The results are discussed in relation to the various mechanisms which have been put forward for the reaction of Na₂S with 1, 4-dichlorobenzene (PPS synthesis).     

Enhancing Local CO2 Adsorption by L-histidine Incorporation for Selective Formate Production Over the Wide Potential Window

Electrochemical carbon dioxide reduction reaction (CO₂RR) to produce valuable chemicals is a promising pathway to alleviate the energy crisis and global warming issues. However, simultaneously achieving high Faradaic efficiency (FE) and current densities of CO₂RR in a wide potential range remains as a huge challenge for practical implements. Herein, we demonstrate that incorporating bismuth-based (BH) catalysts with L-histidine, a common amino acid molecule of proteins, is an effective strategy to overcome the inherent trade-off between the activity and selectivity. Benefiting from the significantly enhanced CO₂ adsorption capability and promoted electron-rich nature by L-histidine integrity, the BH catalyst exhibits excellent FE_formate in the unprecedented wide potential windows (>90 % within −0.1–−1.8 V and >95 % within −0.2–−1.6 V versus reversible hydrogen electrode, RHE). Excellent CO₂RR performance can still be achieved under the low-concentration CO₂ feeding (e.g., 20 vol.%). Besides, an extremely low onset potential of −0.05 V_RHE (close to the theoretical thermodynamic potential of −0.02 V_RHE) was detected by in situ ultraviolet-visible (UV-Vis) measurements, together with stable operation over 50 h with preserved FE_formate of ≈95 % and high partial current density of 326.2 mA cm⁻² at −1.0 V_RHE.     

Phosphorylated imidazo[1,2-a]pyridines

The reaction of phosphorus(III) halides with imidazo[1,2-a]pyridines in the presence of bases leads to the formation of 3-phosphorylated imidazo[1,2-a]pyridines. The reaction proceeds in high yield and requires no catalysts. In the compounds obtained, in contrast to phosphorylated indolizines, the phosphorus–heterocycle bond is stable and not cleaved by dry hydrogen chloride, alcohols, or water. Imidazo[1,2-a]pyridines with the phosphinic and phosphinous groups can be alkylated both at the phosphorus and at the nitrogen atom of the heterocycle, the alkylation direction being dependent on the strength of the alkylation reagent used. © 1995 John Wiley & Sons, Inc.