Articles

Atomically precise metal nanoclusters can serve a variety of purposes, yet their high reactivity also makes them difficult to synthesize. Now, well-defined {Ag₃₀} nanoclusters have been prepared within ring-shaped polyoxometalates. These nanoclusters show good stability in solution and the solid state, can undergo redox-induced structural transformation, and possess exposed surfaces that can serve as catalytically active sites.

Generating aptamers for use as affinity reagents in analytical applications is important, but SELEX, the standard method for aptamer generation, is unable to select for pre-defined binding affinities. Now, by combining efficient particle display, high-performance microfluidic sorting and high-content bioinformatics, the method ‘Pro-SELEX’ can afford the quantitative generation of aptamers with programmable binding affinities.

The ortho-substituted phenyl ring is a basic structural element in chemistry. Now, 2-oxabicyclo[2.1.1]hexanes have been developed as saturated bioisosteres of the ortho-substituted phenyl ring with improved physicochemical properties. Replacement of the phenyl ring with 2-oxabicyclo[2.1.1]hexanes in marketed agrochemicals fluxapyroxad and boscalid improved water solubility, reduced lipophilicity and retained bioactivity.

The use of main-group elements in radical cross-coupling reactions has been little explored. Now, a low-valency bismuth complex has been shown to emulate the behaviour of first-row transition metals and undergo single-electron-transfer oxidative addition to redox-active electrophiles, leading to the development of a bismuth-catalysed C–N coupling reaction between amines and carboxylic acids.

Trihydrogen cations are abundant in interstellar space and play a vital role in both star and organic molecule formation. Now it has been shown that D₃⁺ cations can be directly produced through photoionization of molecular D₂–D₂ dimers.

Supramolecular structures are typically formed by the one-step self-assembly of building blocks. Now, a greater level of control has been achieved using stepwise non-covalent reactions under kinetic control. Two-dimensional block supramolecular polymers with tailored compositions and sequences were synthesized, and a site selectivity that is reminiscent of regioselectivity in covalent synthesis was observed.

Ribosomal incorporation of non-α-amino acid monomers into proteins is largely restricted to in vitro translation. Now, pyrrolysyl-transfer RNA synthetase variants have been shown to acylate tRNAs with α-thio acids, malonic acids, and N-formyl amino acids. This work represents a key step towards the programmed ribosomal synthesis of sequence-defined non-protein polymers in cellulo.

Ultra-high-capacity Li–air batteries have low Coulombic efficiency and degrade during re-charging, resulting in a poor cycle life. Redox mediators enable improvements but only at undesirably high potentials. The origin of this high potential and the impact of purported reactive intermediates has now been elucidated by resolving the charging mechanism using Marcus theory.

H₃⁺ and D₃⁺ serve as initiators of many chemical reactions in interstellar clouds. Now the ultrafast formation dynamics of D₃⁺ from a light-driven bimolecular reaction starting from D₂–D₂ dimers have been measured. It has also been shown that the emission direction of D₃⁺ can be controlled by driving the reaction with a more complex two-colour laser pulse.

The biosynthesis of the methylated sesquiterpene sodorifen, which features a cryptic methylation pattern, has now been studied through extensive labelling experiments and computational chemistry. The methyl group formation is now understood to come from methylene carbons of the substrate farnesyl diphosphate and the absolute configuration of the biosynthetic intermediate presodorifen diphosphate has been revised.

Protein solutions can undergo liquid–liquid phase separation, by condensing into a dense phase that often resembles liquid droplets, which coexist with a dilute phase. Now it is shown that hydrophobic interactions, specifically at interfaces, can trigger a liquid–solid phase separation of a protein solution.

Clathrates—open crystals with a hierarchy of polyhedral cages—are mostly found in atomic and molecular systems. Now, it has been shown through Monte Carlo simulations that the formation of colloidal host–guest clathrates can be driven by entropy alone, through entropy compartmentalization.

A trivalent 4f cationic complex bearing two bis-silylamide ligands has been prepared that displays slow magnetic relaxation. The bulky ligands and weakly coordinating anion stabilize the pseudotrigonal geometry necessary to elicit strong ground-state magnetic anisotropy in this axially coordinated Yb(III) complex with well-localized charges.

1,3-Dipolar cycloadditions are well-known transformations in organic synthesis. However, the reactivity of benzene rings in these processes is underexplored. In situ-generated diazoalkenes have now been shown to undergo intramolecular 1,3-dipolar cycloadditions with aromatic rings. The transformation results in an unaromatized benzene ring that enables the synthesis of functionalized heterocycles.

Cellular membranes contain numerous lipids, and efforts to understand the biological functions of individual lipids demand approaches for controlled modulation of membrane composition in situ. Now, click chemistry-based directed evolution of a microbial phospholipase within mammalian cells affords an editor for optogenetic, targeted modification of phospholipids in cell membranes.

In vitro screening of a ribosomally synthesized macrocyclic peptide library containing cyclic γ^2,4-amino acids (cγAA) afforded the discovery of potent inhibitors of the SARS-CoV-2 main protease (M^pro). A co-crystal structure revealed the contribution of this cγAA to M^pro binding and the proteolytic stability of these macrocycles.

Electronic spin influences chemistry profoundly, but its role in surface chemistry is poorly established. Now the spin-dependent reaction probabilities of oxygen atoms with a graphite surface have been studied. Molecular dynamics simulations help elucidate the mechanism for spin-flipping, which is observed to occur with low probability in surface scattering experiments.

The diverse site-selective functionalization, including multi-functionalization, of C=C double bonds and C(sp³)–H bonds remains a largely unmet challenge. Now, a palladium-catalysed aerobic oxidative method has been developed for the multi-site programmable functionalization of terminal olefins via a strategy that controls the reaction sequence between alkene isomerization and oxidative functionalization.

In situ chirality identification for single-molecule systems is not a straightforward task. Now, real-time chirality identification during a Michael addition reaction has been realized by continuous measurements of spin-polarized currents through a single-molecule junction, providing a promising method for studying symmetry-breaking reactions.

Catenanes are topologically non-trivial and, perhaps for this reason, molecules composed of two oriented rings have always simply been referred to as ‘topologically chiral’. Now it has been shown that the same stereogenic unit can arise in systems whose stereochemistry is Euclidean, suggesting a need to rethink this fundamental form of mechanical chirality.