Research Briefing in 2024

Simultaneous application of mechanical and chemical effects during materials synthesis can increase control of crystallization, but use of this strategy in preparing halide perovskite films is underexplored. Now, a method that integrates rapid chemical crystallization with mechanical shearing enables the fabrication of perovskite films with long-range crystalline order and enhanced optoelectronic properties.

Site-selective C–H bond functionalization of silanes is challenging because of the presence of multiple C–H bonds. Now, a photocatalytic method for the radical β-C(sp³)–H functionalization of silanes using the β-silicon effect is developed, enabling the aminoalkylation, alkylation and arylation of simple silanes to prepare more complex organosilicon compounds.

Simultaneously achieving high energy and carbon efficiency in ethanol electrosynthesis is challenging. Now, an interfacial cation matrix (ICM) is developed that modifies the catalyst microenvironment to increase these performance metrics towards multicarbon products in the acidic CO₂ reduction reaction. Furthermore, combining a tailored Cu–Ag catalyst with the ICM facilitates selective ethanol electrosynthesis.

Singly bonded, low-valent group 13 compounds are rare, and their reactions are typically limited to oxidative additions. Now, a compound with a singly bonded gallium(i) centre has been prepared using a sterically hindered ligand. This compound exhibits varied reactivity, undergoing both oxidative addition and redox-invariant carbometallation reactions.

Sulfur(vi) fluoride exchange and modular diazotransfer reactions have advanced click chemistry, but their mechanisms and reactivity profiles are not well understood. Now, a computational study of these reactions provides mechanistic insights and predictive reactivity models for modular diazotransfer, facilitating the development of an easy-to-prepare and -handle diazotransfer reagent with excellent reactivity.

A strategy is demonstrated for the hierarchical assembly of highly crystalline supramolecular nanotubes and tubular covalent organic frameworks (COFs), driven by cooperative dynamic covalent and coordination bonding. The pore size of the tubular COFs can be precisely controlled, and their reversible demetallation and remetallation could enable further tuning of the properties.

The stereoselectivity of S_N1-type glycosylation reactions involving 4,6-O-benzylidene-protected sugars is determined by a glycosyl cation intermediate. However, these species are usually too unstable to be characterized directly in solution. Now, mass spectrometry is used to capture these ions in a vacuum and to analyse their structure using cryogenic infrared spectroscopy, in conjunction with computational calculations.

A strategy for the cobalt-hydride-catalysed enantioselective hydroalkylation of 1,1-disubstituted styrenes is demonstrated, enabling the efficient construction of chiral tertiary carbon centres at the benzyl position. This method overcomes the requirement for a heteroatom-containing substrate, with enantiocontrol instead achieved through C–H···π interactions between the substrate and catalyst.

Owing to its structural complexity, the total synthesis of alchivemycin A has proved challenging. Now, the total synthesis of alchivemycin A is achieved using a chemoenzymatic approach that combines de novo skeleton construction with a late-stage enzymatic oxidation cascade. Following rational protein engineering of a key enzyme, the final product is obtained in high yield.

Methods for the asymmetric functionalization of unstrained C(sp³)–C(sp³) bonds are rare. Now, strategies are developed for the enantioselective functionalization of allylic C(sp³)–C(sp³) bonds with a palladium catalyst through either kinetic resolution or dynamic kinetic asymmetric transformation.

Carbon capture and utilization offers a solution to reducing CO₂ emissions, but economic feasibility presents a barrier to adoption. Now, an electrochemical reaction is introduced that integrates H₂ production with CO₂ capture and utilization to produce ethylene carbonate with a high yield in aqueous solution. A techno-economic analysis indicates the economic viability of this strategy.

Photocatalysts are crucial to diverse applications, but a challenge is the simultaneous and efficient delivery of photogenerated charges and mass to the catalytic sites. Now, through the systematic design of the skeleton and pores, a covalent organic framework is developed for the efficient photosynthesis of hydrogen peroxide using only water, air and light.

Palladium can be stabilized in the zero-oxidation state with one, two or three anionic aluminium ligands to produce mono-, di- or trianionic complexes, respectively. The palladium centres in the resulting complexes are highly negatively charged, and this electron richness enables the trianionic complex to undergo a hitherto hypothetical oxidative addition reaction with a diboron species.

An artificial metalloenzyme based on streptavidin with a biotinylated Rh(III) cofactor provides enantioselective access to various isoindolones with different functional groups. Rational engineering of the streptavidin scaffold reverses the stereoselectivity, offering an enantiodivergent method for the synthesis of isoindolones.

Monolayer gold could exhibit properties of benefit to various applications, but has been challenging to synthesize. Now, the exfoliation of two-dimensional single-atom-thick gold layers — termed goldene — is achieved through wet-chemically etching away Ti₃C₂ from Ti₃AuC₂, a nanolaminated MAX-phase. Goldene shows lattice contraction and an increase in the gold 4f binding energy compared with the bulk.

A strategy for the precise and scalable synthesis of a series of M₁M₂ (where M is a metal ion) heteronuclear dual-atom catalysts (DACs) is proposed. Photoinduced electron accumulation at the M₁ sites results in the capture and reduction of M₂ cations close to the M₁ sites to generate DACs with high purity.

The enantioselective synthesis of an inherently chiral molecular nanographene is demonstrated by precisely controlling the sequential generation of chiral elements in its structure. The final stereocontrolled graphitization step allows for the separate synthesis of both enantiomers, thus paving the way towards chirality controlled all-carbon nanographenes.

A general strategy for synthesizing high-nuclearity Cu(i) alkynide nanoclusters is developed, involving a tripodal polydentate phosphoramide ligand to stabilize the nanoclusters and an alkynol ligand for the facile in situ generation of the ethynediide (C₂^2–) dianion to template nanocluster formation. The Cu(i) alkynide nanocluster Cu62 exhibits good stability and activity as a catalyst for photobleaching.

The direct carbonylation of alkanes with CO suffers from low conversion owing to equilibrium constraints. Now, a strategy is presented that combines reversible alkane carbonylation with an asymmetric transformation to overcome the equilibrium limitations, enabling the synthesis of chiral β- and α-amino ketones from alkanes, CO and anilines.

The visible-light-driven thiolate-catalysed carboxylation of C(sp²)–H bonds in azines using CO₂ is demonstrated. This procedure can be applied to various azine substrates to obtain a range of N-heteroaromatic carboxylic acids with different functionalities, including bioactive molecules and carboxylated N-ligands.