Search

Herein, we report a mild dearomative [5+2]/[2+2] cycloaddition of 1H-indoles with ortho-(trimethylsilyl)aryl triflates. The unique [5+2] cycloaddition enables the synthesis of a series of dibenzo[b,e]azepine derivatives in moderate to good yields. Increasing the steric hindrance at the C2-position of 1H-indoles leads to the [2+2] cycloaddition. Mechanistic investigations support that the reaction of 1H-indoles with arynes undergoes a [2+2] cycloaddition step, followed by a ring expansion to the [5+2] cycloaddition product. [ABSTRACT FROM AUTHOR]

The electrochemical nitrogen reduction reaction (NRR) is a promising but extremely challenging approach for ammonia synthesis under ambient conditions. Herein, we report the excellent NRR performance of gold nanoparticles (AuNPs) with multiple high-index facets, prepared by a modified seed-mediated method. At −0.3 V vs. RHE and in 0.1 M Li2SO4 aqueous solution, the AuNPs afford the highest faradaic efficiency (FE) of 73.32% reported so far, with a remarkable ammonia generation rate of 9.22 μg h−1 cm−2. Density functional theory (DFT) calculations reveal that the high-index faceted surfaces of the AuNPs have greater preference for the adsorption of NRR intermediates (*NNH) and significantly hinder the adsorption of competing hydrogen evolution intermediates (*H). [ABSTRACT FROM AUTHOR]

Chiral Ni(ii)-complexes of N,N′-dioxides show high catalytic activity and enantioselectivity in catalysing the asymmetric Friedel–Crafts C3-alkylation of 2,5-dimethyl pyrrole to β,γ-unsaturated α-ketoesters. A dramatic reversal of enantioselectivity is realized with ligands derived from the same type of chiral source of l-ramipril, by slightly tuning the amide units. [ABSTRACT FROM AUTHOR]

A simple, yet efficient synthetic approach for the construction of vinylene-linked conjugated porous networks was developed. Based on the Horner–Wadsworth–Emmons reaction, the condensation polymerization for the formation of an sp2 carbon-linkage can be achieved at room temperature. The resulting vinylene-linked frameworks exhibit a promising porous nature with the best surface area of up to 1373 m2 g−1. Their intrinsic conjugated architectures and semiconducting properties lead to photocatalytic evolution of hydrogen from water under visible light irradiation. This new synthesis method provides a facile means to prepare attractive sp2 carbon linked porous organic frameworks. [ABSTRACT FROM AUTHOR]

As a kind of metal-free material, graphitic carbon nitride (g-C3N4) is widely used in catalytic materials, energy storage materials and other fields. However, the limited light absorption, low conductivity and high recombination rate of the photogenerated electron–hole pairs limit its further application. Constructing g-C3N4 based composite materials by integrating it with carbon materials is an effective and common way to overcome the above shortcomings of g-C3N4. In this paper, carbon materials, such as carbon dots, carbon nanotubes, graphene, and carbon spheres, are integrated with g-C3N4 to construct carbon/g-C3N4 composite materials (CCNCS) and their photoelectrocatalytic performance is reviewed. The effects of those factors such as the categories of carbon materials, carbon content, nitrogen content, the morphology of g-C3N4, and the interfacial interactions between carbon and g-C3N4 on the photo/electrocatalytic performance of CCNCS are carefully analyzed to help researchers to touch the nature of the synergistic effect of g-C3N4 and the carbon ingredient in CCNCS. [ABSTRACT FROM AUTHOR]

Violet phosphorus, a non-metallic elemental layered structure, has not been reported as a photocatalyst due to the lack of its resources. An excellent photocatalytic H2 evolution rate of 675 ± 109 μmol h−1 g−1 with high stability has been achieved by the violet phosphorus simply dispersed in deionized water with addition of 1.0 wt% of co-catalyst Pt, which is much higher than that obtained from black phosphorus. The H2 evolution rate was observed to reach values as high as 553 μmol h−1 g−1 with addition of 0.5 wt% co-catalyst Pt. [ABSTRACT FROM AUTHOR]