Volume 6 Issue 4, April 2023

The discovery of the Tetrahymena group I intron’s self-splicing defined RNAs as capable catalysts. Now, cryogenic electron microscopy structures of this ribozyme have revealed large conformational changes and mechanistic details of its two-step mode of action.

In a standard electrochemistry experiment, the electrochemical signal reports on all electron transfer, chemical, and diffusion steps between the anode and cathode. Now, a membrane reactor decouples each of these steps to enable direct measurement of elementary reaction steps in ways that are otherwise not possible.

Electrochemical hydride (H^–) transfer has been an elusive process. Now, using well-designed model systems, the phenomenon has been isolated and further demonstrated as a practical synthetic method with H₂ gas as the hydrogen source.

Although the Tetrahymena group I intron was the first RNA catalyst discovered, important mechanistic details remain ambiguous. Now six different conformational states of Tetrahymena group I intron self-splicing and an unexpected pseudoknotted structure are resolved by cryogenic electron microscopy.

Electrosynthesis of higher carbon products (C₄₊) in a high selectivity has not been achieved by the direct reduction of CO₂ or CO. Here, the authors use a cascade electrocatalysis–thermocatalysis approach to produce butane from CO with an overall selectivity of 43%.

Direct CO₂ electroreduction on Cu-based catalysts has been used to produce C₂ products but yields of C₃ products have remained low. Here a CO₂ supersaturation strategy is used to promote electrodeposition of a highly alloyed CuAg electrode and its subsequent selectivity towards 2-propanol.

Conjugate cyanation of linear α,β-unsaturated aldehydes has remained an unsolved synthetic challenge. Now a method based on organocatalysis and photoredox catalysis is developed that facilitates this process asymmetrically, leading to an exclusive 1,4-chemoselectivity.

Charge transfer and chemical kinetics both contribute to the overall overpotential that is observed in a typical electrocatalytic experiment, but it remains difficult to resolve the individual contributions. Here a Pd membrane double cell is used to separate the charge transfer and chemical steps in the hydrogen evolution reaction to evaluate how experimental conditions affect the individual steps.

Although homogeneous hydride transfer reactivity is well understood, the heterogeneous counterpart at metal surfaces remains rather unexplored. This work introduces the electrocatalytic hydrogen reduction reaction, which in net reduces H₂ to reactive hydrides via the intermediacy of surface M−H species. The study reveals that hydride transfer from surface M−H species can be driven by electrical polarization.

The Lebedev process is an established approach to convert ethanol into butadiene catalysed by silica–magnesia prepared by the so-called wet-kneading method. However, the role and impact of this wet-kneading approach have not been fully uncovered. Here the authors reveal important aspects of this process and elucidate the role of the different active sites it generates within silica–magnesia.