Articles

The preparation of functionalized amino acids from inexpensive aldehydes is challenging. This work describes the biocatalytic synthesis of l-methionine by applying gaseous CO₂ pressure and a coupled amination step to drive the unfavoured equilibrium of a reverse carboxylation reaction.

Supported metal nanoparticles are indispensable catalysts in industry, yet they are often subjected to severe sintering. Now, a general method based on metal immobilization within zeolite is reported for the preparation of highly sinter-resistant catalysts for a broad range of industrially relevant processes.

The properties of polymers depend on monomer composition and chain length, but regulating these structural features during polymer synthesis is a challenge. Now Hecht and co-workers report a photoswitchable catalyst system that can repeatedly be switched between ON and OFF states, allowing remote control of the polymerization process. Furthermore, copolymerization with control over monomer incorporation is demonstrated.

Predicting metal–support combinations that can afford stable single-atom catalysts remains a complex problem. Now, a computational method is reported that can be used to screen interaction strengths between metals and supports and identify those pairs that generate strongly adsorbed single-atom catalysts.

Organic synthesis relies on the ability to convert simple starting materials into compounds with greater molecular complexity. Here, Trost and co-workers use branched aldehydes as nucleophiles for asymmetric Mannich reactions, and the products of these reactions as electrophiles for the addition of a range of carbon nucleophiles. This provides a simple, stereodivergent route to 1,3-aminoalcohols.

Electrolysis uses clean electricity to form chemical products but typical water electrolysis produces hydrogen which is hard to store oxygen which is a waste gas. Here, paired electrolysis is performed with an palladium membrane reactor to carry out two organic reactions simultaneously. The dense palladium membrane enables the two reactions to proceed in different solvents and the reaction rates and selectivities can be independently controlled.

Cross-coupling of aryl compounds is one of the most powerful carbon–carbon bond forming reactions available, and typically involves the use of expensive and scarce palladium salts. Here Bedford and co-workers show that iron can be an effective catalyst for Suzuki biaryl couplings.

The conversion of carbon dioxide into multi-carbon alcohols would enable the synthesis of sustainable liquid fuels with high energy densities. Now, vacancy-engineered core–shell copper-based catalysts are able to shift the selectivity of electrochemical CO₂ reduction into alcohols instead of alkenes, as obtained with bare-copper catalysts.

The proper verification of the stability of metal oxide catalysts for water electrolysis in acid electrolyte remains unresolved. Here, the ‘stability number’ is introduced to evaluate the dissolution mechanisms of various iridium-based oxides and to facilitate benchmarking of catalysts independent of loading, surface area or involved active sites.

Catalytic arene carboxylation with CO₂ is a challenging reaction, with limited substrate scope and selectivity. Now, a redox neutral method based on a ligand-assisted Rh-catalysed C–H activation is shown, which features broad scope and provides access to important and biologically relevant structural motifs

Alcohols serve as versatile intermediates for the synthesis of pharmaceuticals and other valuable compounds. Here, Contente and Paradisi developed self-sustainable biocatalytic flow systems for the conversion of amines into various non-commercially-available and high-value alcohols.

The Fe protein of nitrogenase contains a redox-active [Fe₄S₄] cluster that plays a key role in electron transfer and substrate reduction. Here, Hu and co-workers show that the Fe protein of Methanosarcina acetivorans can reduce CO₂ and CO to hydrocarbons under ambient conditions.

Dynamic kinetic resolution (DKR) allows the conversion of both enantiomers of a racemic mixture into a single enantiomer of product, and requires both a stereoselective reaction and a means of rapidly racemizing the starting materials. Here, a highly stereoselective iridium-catalysed DKR of secondary allylic alcohols is reported, with mechanistic studies implying that substrate racemization is achieved through carbon–oxygen bond cleavage.

The generation of hydrogen fuel from water and visible light requires photoelectrodes that are inexpensive, stable and highly active. Now, Luo, Grätzel and co-workers report Cu₂O photocathodes that reach these goals. Incorporation into an unassisted solar water splitting device gives ~3% solar-to-hydrogen conversion efficiency.

The structural modification of inactive materials to effectively engineer active catalysts is very attractive. Here, layered crystalline Pd₃P₂S₈ is transformed by electrochemical lithiation into amorphous Li-incorporated nanodots. This process turns the inert parent material into a highly active and stable hydrogen-evolving catalyst.

Catalytic oxybromination is an important strategy for the upgrade of methane. Here, Pérez-Ramírez and co-workers employ operando photoelectron photoion coincidence spectroscopy as well as kinetic analyses and molecular simulations to unravel the complex reaction mechanism.

Methane borylation allows for the functionalization of an otherwise unreactive compound, enabling its use as a one-carbon building block; however, competing diborylation presents a selectivity issue. Now, a metal–organic-framework-based catalyst highly selective for monoborylation is reported. The selectivity is due to the reaction taking place within the catalyst pores, which excludes the formation of the larger diborlyated product.

Reactive metal–support interactions can tune the activity of heterogeneous catalysts, but have mainly been reported for oxide supports. Now, the metal–support interaction of platinum with MXenes at moderate temperature is reported, using the water-gas shift reaction as an example to showcase the properties of a representative catalyst.

Access to renewable hydrogen represents an important target for the success of the hydrogen economy. Now, a one-pot method is presented for the conversion of cellulosic biomass into hydrogen via formic acid as the intermediate, followed by its application to a fuel cell.

Energy-based descriptors have proven very successful in recent years despite their impracticality from an experimental viewpoint. Here, a universal descriptor based only on electronegativities and coordination numbers is put forward to predict the activity of carbon-based single-metal-atom catalysts for three of the most important electrocatalytic reactions. This descriptor can be extended to metal–macrocycle complexes with similar coordination environments.