The photoelectrochemical synthesis of valuable multicarbon products from carbon dioxide, sunlight and water is a promising pathway for clean energy generation and carbon neutrality. However, it is challenging to create and stabilize efficient C–C coupling sites to achieve multicarbon products with high selectivity, yield and stability. Here we designed a low-coordinated copper-cluster catalyst interfacially coupled in situ with a GaN nanowire photocathode, achieving a high ethylene Faradaic efficiency of ∼61% and a partial current density of 14.2 mA cm−2, with a robust stability of ∼116 h. The in situ self-optimized Ga–N–O interface was confirmed to facilitate and stabilize the interfacially oxidized copper species of copper clusters, which function as efficient C–C coupling sites for ethylene production. Furthermore, the hydrogen-feeding effect of GaN for promoting CO hydrogenation also guides the facile CHO-involved C–C coupling pathway. This work sheds light on the interface design and understanding of efficient and stable (photo)electrosynthesis of highly valuable fuels from CO2.
The development of the sulfur(VI)–fluoride exchange (SuFEx) and modular diazotransfer (MoDAT) reactions represent important milestones in the evolution of click chemistry. However, their reactivity profiles, chemoselectivity origins and underlying mechanisms remain unclear. Here we report a computational study of the MoDAT and SuFEx pathways, focusing on the reaction between the diazotransfer reagent fluorosulfuryl azide and primary amines. Our calculations reveal that the MoDAT reaction possesses a small kinetic barrier and a strong driving force, making it kinetically and thermodynamically more favourable than the SuFEx reaction. Through mechanistic scrutiny and structure–activity relationship studies, we have formulated predictive models for the reactivity and selectivity of the MoDAT reaction. Leveraging these insights, an easy-to-prepare and easily handled diazotransfer reagent with excellent reactivity has been developed, which holds broad promise for applications in chemistry and biology.
The design of supramolecular hydrogels comprising aligned domains is important for the fabrication of biomimetic materials and applications in optoelectronics. One way to access such materials is by the self-assembly of small molecules into long fibres, which can be aligned using an external stimulus. Out-of-equilibrium supramolecular gels can also be designed, where pre-programmed changes of state can be induced by the addition of chemical fuels. Here we exploit these dynamic properties to form materials with aligned domains through a ‘forging’ approach: an external force is used to rearrange the underlying network from random to aligned fibres as the system undergoes a pre-programmed gel-to-sol-to-gel transition. We show that we can predictably organize the supramolecular fibres, leading to controllable formation of materials with aligned domains through a high degree of temporal control.
Controlled synthesis of metastable materials away from equilibrium is of interest in materials chemistry. Thin-film deposition methods with rapid condensation of vapour precursors can readily synthesize metastable phases but often struggle to yield the thermodynamic ground state. Growing thermodynamically stable structures using kinetically limited synthesis methods is important for practical applications in electronics and energy conversion. Here we reveal a synthesis pathway to thermodynamically stable, ordered layered ternary nitride materials, and discuss why disordered metastable intermediate phases tend to form. We show that starting from elemental vapour precursors leads to a 3D long-range-disordered MgMoN2 thin-film metastable intermediate structure, with a layered short-range order that has a low-energy transformation barrier to the layered 2D-like stable structure. This synthesis approach is extended to ScTaN2, MgWN2 and MgTa2N3, and may lead to the synthesis of other layered nitride thin films with unique semiconducting and quantum properties.
Sulfation, a ubiquitous post-translational modification in biomolecules, primarily targets substrates containing OH groups through O-sulfonation (O–SO3). A method for sulfation via the formation of C–O bonds has the potential to access organic sulfates from a broad substrate scope and in a stereoselective manner but remains elusive. Stereospecific C–O bond formation via 1,2-metallate migration in peroxide oxidation has not been deployed to create any other valuable C–O bonds apart from C–OH. Here we describe a fundamentally unique reactivity of persulfate salts for stereospecific C–O sulfation via 1,4-metallate migration. With the aid of readily accessible, stereodefined organic boron compounds derived from native functionalities and a tandem borylation–sulfation approach, our study thus expands to include hydrosulfation of alkenes, C–H sulfation, decarboxylative sulfation, dehalogenative sulfation and deaminative sulfation, which are not otherwise readily accessible.
Natural proteins must fold into complex three-dimensional structures to achieve excellent mechanical properties vital for biological functions, but this has proven to be exceptionally difficult to control in synthetic systems. As such, the long-standing issue of low mechanical rigidity and stability induced by misfolding constrains the physical and chemical properties of self-assembling peptide materials. Here we introduce a mixed-chirality strategy that enhances folding efficiency in topologically interlocked metallopeptide nanostructures. The orderly entanglement of heterochiral peptide-derived linkers can fold into a compact three-dimensional catenane. These folding-mediated secondary structural changes not only generate biomimetic binding pockets derived from individual peptide strands but also result in strong chiral amplification by the tight interlocking manner. Notably, this strategic ‘chirality mutation’ alters their arrangement into tertiary structures and is pivotal in achieving exceptional mechanical rigidity observed in the metallopeptide crystals, which exhibit a Young’s modulus of 157.6 GPa, approximately tenfold higher than the most rigid proteinaceous materials in nature. This unusual nature is reflected in enhanced peptide-binding properties and heightened antimicrobial activities relative to its unfolded counterpart.
In 2012, bicyclo[1.1.1]pentanes were demonstrated to be bioisosteres of the benzene ring. Here, we report a general scalable reaction between alkyl iodides and propellane that provides bicyclo[1.1.1]pentane iodides in milligram, gram and even kilogram quantities. The reaction is performed in flow and requires just light; no catalysts, initiators or additives are needed. The reaction is clean enough that, in many cases, evaporation of the reaction mixture provides products in around 90% purity that can be directly used in further transformations without any purification. Combined with the subsequent functionalization, >300 bicyclo[1.1.1]pentanes for medicinal chemistry have been prepared. So far, this is the most general and scalable approach towards functionalized bicyclo[1.1.1]pentanes.