Research articles

The fabrication of single-metal-atom chains in an atomically precise way is challenging. Now, a chemical vapour co-deposition method is reported for the synthesis of highly ordered single-atom chains of platinum with lengths of up to 20 nm on a wafer-scale. The metallic behaviour of the single-metal-atom chain is revealed by electronic measurements, first-principle calculations and complex network modelling.

The synthesis of α,α-disubstituted α-amino acids and peptides is often limited by the need to couple sterically hindered substrates. Now, copper-catalysed dehydrogenative coupling of α-amino acid Schiff bases and hydrocarbon feedstocks has been developed. Application of this method to peptides enables the incorporation of sterically hindered α-amino acid motifs, which impart a stabilizing helical effect on the peptide structure.

The pulp and paper industry produces approximately 50 million metric tons of lignin per year as a waste product. Here, lignin is shown to act as a photocatalyst for the solar-driven synthesis of hydrogen peroxide from H₂O and O₂ under visible light. Coupling this photocatalytic process with unspecific peroxygenases enables the enantioselective oxyfunctionalization of C–H bonds.

C-glycosides form the basis of numerous therapeutic compounds, but their synthesis using sustainable catalysts is a challenge. Here, an iron-catalysed reductive cross-coupling method is developed that couples glycosyl radicals, generated in situ from glycosyl chlorides, with unsaturated electrophiles. Mechanistic experiments indicate that the active catalytic species is a low-valent iron complex.

Derivatives of fluorinated alkenes are commonly found in biologically active molecules, but their synthesis remains challenging. Towards this goal, a rhodium-catalysed method for the selective β- or γ-addition of nucleophiles to gem-difluoroallenes has now been developed. Catalysts with N- or P-based ligands result in the β- or γ-selective addition, respectively, of amines and thiols to gem-difluoroallenes.

High-entropy materials are used in a range of applications but their synthesis at the nanoscale remains challenging. Now, a robust and general strategy to prepare high-entropy alloy and ceramic nanoparticles has been developed using laser scanning ablation. This approach takes only five nanoseconds per pulse to ablate precursors at atmospheric temperature and pressure.

The solidification of liquid metal alloys drives phase separation and pattern formation. Now, it emerges that the solidification of liquid metal alloys on a surface follows unique solidification patterns that reveal alternating convergent and divergent growth habits, leading to oscillatory bifurcation patterns.

Mild and metal-free direct α-arylation of ketones has long been a challenging transformation. Now, a metal-free photoredox approach has been developed using electron-rich acridinium ions to photoactivate C(sp²)–X bonds under low-energy green light and to catalyse the α-arylation of cyclic ketones. This approach is a multigram and sustainable methodology for the synthesis of pharmaceutical synthons.

Taking inspiration from palladium–norbornene cooperative catalysis, Catellani-type reactions are now performed using a hybrid olefin ligand with a P or S coordination site. This olefin ligand enables efficient ipso,ortho-difunctionalization of iodoarenes. Mechanistic studies show the formation of organopalladium intermediates that comprise both the substrate and the hybrid olefin ligand.

Sulfoximines and sulfonimidoyl groups have recently emerged as powerful pharmacophores, however, their synthesis and incorporation into complex molecules is typically limited by long synthetic routes and the need to control stereogenic S-centres. Now, a stereospecific S_NAr approach has been developed for the synthesis of α-(hetero)arylation of sulfonimidoyl motifs.

Iterative sequences of organic reactions can be automated but are rare and challenging to identify. Now, a computer-driven strategy is reported for the systematic discovery and evaluation of such sequences. Several of the iterative sequences are validated experimentally and enable the syntheses of useful motifs in natural product targets.

A ternary catalytic method combining organic photoredox, hydrogen atom transfer and nickel catalysis is reported. This combination can directly arylate the allylic C(sp³)–H bonds of a broad range of readily available olefins. Mechanistic experiments, coupled with density functional theory calculations aid the elucidation of the ternary catalytic cycle and the origin of regioselectivity.

A sonochemical route rapidly synthesizes covalent organic frameworks (COFs) in aqueous solutions of acetic acid. This method has operational advantages compared with conventional solvothermal routes and yields COFs of higher crystallinity and porosity, and hence improved materials properties.

In photoelectrochemical (PEC) cells, water oxidation to O₂, when coupled to CO₂ reduction, typically requires a pair of light absorbers or an applied bias voltage. Now, a bias-free PEC cell with a single sunlight absorber drives simultaneous CO₂ reduction to give formate, and the oxidation of an organic substrate in aqueous conditions.

Large single crystals of charged 2D polymers are synthesized on a water surface, under kinetic control, by the irreversible Katritzky reaction. The crystals can act as an anion-selective membrane for osmotic energy generation.