Articles in 2022

His-C2-directed modification is chemically challenging and rarely occurs in nature due to the low reactivity of this position. Now, the prenlytransferase LimF has been discovered and applied for geranylation of histidine-containing peptides and imidazole-containing small molecules, showcasing the versatility of this biocatalyst.

Enzymes for poly(ethylene terephthalate) (PET) deconstruction are of interest for plastics recycling, but reports on their directed evolution are missing. Now, an automated, high-throughput directed evolution platform is described, affording HotPETase that effectively achieves depolymerization above the glass transition temperature of PET.

Eukaryotic cytochrome P450s (P450s) are often required for the biosynthesis of natural products, but their performance in bacteria is usually reduced. Now, scaffold enzymes bring eukaryotic P450s and a reductase in close proximity for efficient electron channelling, increasing the production of natural products in Escherichia coli.

Allylic amination of unactivated alkenes with aliphatic amines is a long-standing synthetic challenge in organic chemistry. This is now accomplished in an oxidant-free, site-selective process by using a combination of a photocatalyst and cobalt complex for the coupling of olefins and alkyl amines with hydrogen evolution.

Conversion of CO₂ to fuels or chemicals via artificial photosynthesis usually requires the assistance of organic additives or electricity. Now, a biohybrid system is reported consisting of a photocatalyst sheet and bacteria producing acetate and O₂ from CO₂ and H₂O using sunlight as the sole energy input.

Alkali metal cations influence electrocatalytic reactions, but their specific role remains elusive. Now, methyl₄N⁺ is established as a vibrational probe for surface-enhanced infrared absorption spectroscopy, revealing that alkali metal cations specifically adsorb on Au during CO₂ electroreduction and that their surface coverage depends on their free energy of hydration.

The deployment of fuel cells demands more efficient electrode–electrolyte interfaces to catalyse the oxygen reduction reaction (ORR). A kinetic ORR descriptor is put forward, which is related to the rate of the *O ↔ *OH transition and includes electrolyte effects via the role of non-specifically adsorbed anions.

The conversions of methanol or methyl chloride over zeolite catalysts are promising processes to produce valuable hydrocarbons, but their mechanisms are still not fully understood. Now these are evaluated using operando photoelectron photoion coincidence spectroscopy, which enables the direct observation of elusive intermediates such as methyl radicals or ketene.

Although pyrene-containing molecules have been studied for their optical properties, the outcome of their incorporation into mechanically interlocked structures remains underexplored. Here, the authors install pyrene units into homo[2]catenanes and investigate the formation of long-lived triplet states, which can be exploited for photocatalysis.

Syngas conversion to hydrocarbons on oxide–zeolite bifunctional catalysts is a promising process, yet a complete mechanistic understanding is still lacking. Now the reaction network has been comprehensively evaluated on ZnAlO_x/H-ZSM-5 using a combination of NMR- and gas chromatography-based techniques.

Cu-based catalysts have dominated CO₂ electroreduction as a result of their unique ability to produce C₂ or C₃ products, while Ni has largely been excluded due to poisoning by intermediate CO. Here, inorganic Ni oxygenate-derived electrocatalysts with polarized Ni^𝛿+ sites can produce multicarbon products, including C₃ to C₆ hydrocarbons.

Flavin-dependent halogenases catalyse the challenging regioselective halogenation of aromatic compounds, but display low efficiency. Now, a tryptophan-halogenase with multiple catalytic improvements is obtained by engineering the intermediate transfer tunnel connecting the enzyme´s two active sites.

Catalysis is a crucial strategy for improving the performance of sulfur cathodes in Li–S batteries, yet few strategies have been established to design effective catalysts. Here, by uncovering a volcano-shaped trend between polysulfide adsorption and catalytic rate in transition-metal-doped ZnS, a highly efficient ternary sulfide is developed.

Comprehensive information on enzyme catalytic rates is essential to understand the metabolism of cells, but only a small fraction has been determined experimentally. Now, a deep learning model is developed to predict k_cat values of metabolic enzymes on a large scale using substrate SMILES and protein sequence information.

The widespread adoption of fuel cells requires exhaustive screening for highly active and durable Pt-based catalysts for the oxygen reduction reaction. Now a binary descriptor based on experimental parameters extracted from X-ray absorption spectroscopy is used to predict the catalytic activity and stability of a wide range of Pt-alloy catalysts.

Acidic conditions present a solution to carbonate formation in CO₂ electrolysis but create a selectivity issue through competing H₂ evolution. Here, theoretical methods are used to optimize acidity and select Pd–Cu as a selective electrocatalyst for acidic CO₂ reduction with negligible carbonate crossover and high single-pass carbon efficiency.

The high cost of Pt severely limits fuel cell deployment, but alternative Pt-free catalysts suffer from a low activity and, especially, durability. Now, a low-Pt-content catalyst consisting of Pt and Fe single atoms, dispersed on a nitrogen-doped carbon matrix, and Pt–Fe nanoparticles is shown to exhibit excellent activity and durability in fuel cells.

Olefin metathesis is a powerful synthetic method that largely rests on the reactivity of molybdenum- and ruthenium-based catalysts, as alternative metals have not yet been successfully substituted. Here the authors engineer an iron catalyst to effectively perform the stereoselective ring-opening metathesis polymerization of norbornene.

Hybrid 2D/3D ring systems have emerged as important scaffolds in medicinal chemistry, but efficient protocols for their synthesis are scarce. Now, energy-transfer-mediated cascade dearomative [2 + 2] cycloaddition/rearrangement reactions are developed to provide facile access to pyridine-fused 2D/3D ring systems.

Heterogenized molecular catalysts are often assumed to operate via analogous mechanisms to their homogeneous counterparts. Here, the authors demonstrate that a tethered cobalt porphyrin exhibits either molecule-like or metal-like behaviour depending on the strength of adsorption between the molecule and the electrode surface.