Developing green-safe, efficient and recyclable catalysts is crucial for the chemical industry. So far, organic photocatalysis has been proved to be an environmentally friendly and energy-efficient synthetic technology compared with traditional metal catalysis. As a versatile catalytic platform, hyper-crosslinked polymers (HCPs) with large surface area and high stability are easily prepared. In this report, we successfully constructed two porous HCP photocatalysts (TZ-HCPs) featuring s-tetrazine units and surface areas larger than 700 m² g⁻¹ through Friedel–Crafts alkylation reactions. The rational energy-band structures and coexisting micro- and mesopores endow TZ-HCPs with excellent activities to realize the green synthesis of benzimidazoles (28 examples, up to 99% yield, 0.5–4.0 h) in ethanol. Furthermore, at least 21 iterative catalytic runs mediated by TZ-HCP1D were performed efficiently, with 96–99% yield. This study of TZ-HCPs sheds light on the wide-ranging prospects of application of HCPs as metal-free and green photocatalysts for the preparation of fine chemicals.

The utilization of readily available and non-toxic water by photocatalytic water splitting is highly attractive in green chemistry. Herein we report that light-induced oxidative half-reaction of water splitting is effectively coupled with reduction of organic compounds, which provides a light-induced avenue to use water as an electron donor to enable reductive transformations of organic substances. The present strategy allows various aryl bromides to undergo smoothly the reductive coupling with Pd/g-C₃N₄* as the photocatalyst, giving a pollutive reductant-free method for synthesizing biaryl skeletons. Moreover, the use of green visible-light energy endows this process with more advantages including mild conditions and good functional group tolerance. Although this method has some disadvantages such as a use of environmentally unfriendly 1,2-dioxane, an addition of Na₂CO₃ and so on, it can guide chemists to use water as a reducing agent to develop clean procedures for various organic reactions.

It is fascinating to use water as a hydrogen source to enable the hydrogenation of organic molecules in green chemistry. Nevertheless, current light-driven strategies suffer from an expense of reductants for proton reduction due to a high difficulty in overall water splitting. Herein, we have overcome this challenge and report that light-induced overall water splitting is coupled with hydrogenation of aryl bromides by cooperative catalysis between recyclable Pd/g-C₃N₄ and Fe species, which opens up a photocatalytic avenue to use water as both an electron donor and a hydrogen source to enable hydrogenation of aryl bromides, avoiding the use of additional reductants. Moreover, mild conditions, recyclable catalyst systems and the use of visible-light as the energy source make this process greener. The present method also allowed various high value-added deuterated arenes to be effectively synthesized. This work will guide chemists to use water as both an electron donor and a hydrogen source to develop green procedures for the hydrogenation of various organic compounds.

A new and effective method was developed for the synthesis of aromatic nitriles from arylacetic acids by using NaNO₂ as the nitrogen source and Fe(OTf)₃ as the promoter at 50 °C. A series of arylacetic acids underwent this transformation to give the targeted products in yields of 51–90%. Because of the mild conditions, the reaction is compatible with a broad range of functional groups, including ester, carboxy, hydroxy, acetamido, halo, nitro, cyano, methoxy, and even highly reactive formyl groups. Received: 02 July 2020 Accepted after revision: 31 August 2020 Publication Date: 28 September 2020 (online) © 2020. Thieme. All rights reserved Georg Thieme Verlag KG Rüdigerstraße 14, 70469 Stuttgart, Germany

A direct method was developed for the conversion of benzyl ethers into aryl nitriles by using NH₄OAc as the nitrogen source and ­oxygen as the terminal oxidant with catalysis by TEMPO/HNO₃; the method is valuable for both the synthesis of aromatic nitriles and for the deprotection of ether-protected hydroxy groups to form nitrile groups in multistep organic syntheses.

Ultrathin BiOX/rGO (X = F, Cl, Br, and I) nanosheets serve as novel sulfur hosts in Li–S batteries. The influence of X on the electrochemical performance and redox mechanism is elucidated through in situ Raman/XRD characterization and DFT analysis.