Nature chemistry最新文献

The storage of hydrogen is key to its applications. Developing adsorbent materials with high volumetric and gravimetric storage capacities, both of which are essential for the efficient use of hydrogen as a fuel, is challenging. Here we report a controlled catenation strategy in hydrogen-bonded organic frameworks (RP-H100 and RP-H101) that depends on multiple hydrogen bonds to guide catenation in a point-contact manner, resulting in high volumetric and gravimetric surface areas, robustness and ideal pore diameters (~1.2–1.9 nm) for hydrogen storage. This approach involves assembling nine imidazole-annulated triptycene hexaacids into a secondary hexagonal superstructure containing three open channels through which seven of the hexagons interpenetrate to form a seven-fold catenated superstructure. RP-H101 exhibits high deliverable volumetric (53.7 g l⁻¹) and gravimetric (9.3 wt%) capacities for hydrogen under a combined temperature and pressure swing (77 K/100 bar → 160 K/5 bar). This work illustrates the virtues of supramolecular crystals as promising candidates for hydrogen storage.

Triplex DNA structures, formed when a third DNA strand wraps around the major groove of DNA, are key molecular regulators and genomic threats. However, the regulatory network governing triplex DNA dynamics remains poorly understood. Here we reveal the binding and functional repertoire of proteins that interact with triplex DNA through chemoproteomic profiling in living cells. We develop a chemical probe that exhibits exceptional specificity towards triplex DNA. By employing a co-binding-mediated proximity capture strategy, we enrich triplex DNA interactome for quantitative proteomics analysis. This enables the identification of a comprehensive list of proteins that interact with triplex DNA, characterized by diverse binding properties and regulatory mechanisms in their native chromatin context. As a demonstration, we validate DDX3X as an ATP-independent triplex DNA helicase to unwind substrates with a 5′ overhang to prevent DNA damage. Overall, our study provides a valuable resource for exploring the biology and translational potential of triplex DNA.

Catalytic asymmetric dearomatization represents a powerful means to convert flat aromatic compounds into stereochemically well-defined three-dimensional molecular scaffolds. Using new-to-nature metalloredox biocatalysis, we describe an enzymatic strategy for catalytic asymmetric dearomatization via a challenging radical mechanism that has eluded small-molecule catalysts. Enabled by directed evolution, new-to-nature radical dearomatases P450_rad1–P450_rad5 facilitated asymmetric dearomatization of a broad spectrum of aromatic substrates, including indoles, pyrroles and phenols, allowing both enantioconvergent and enantiodivergent radical dearomatization reactions to be accomplished with excellent enzymatic control. Computational studies revealed the importance of additional hydrogen bonding interactions between the engineered metalloenzyme and the reactive intermediate in enhancing enzymatic activity and enantiocontrol. Furthermore, designer non-ionic surfactants were found to significantly accelerate this biotransformation, providing an alternative means to promote otherwise sluggish new-to-nature biotransformations. Together, this evolvable metalloenzyme platform opens up new avenues to advance challenging catalytic asymmetric dearomatization processes involving free radical intermediates.

Infinite-layer transition metal oxides with two-dimensional oxygen coordination exhibit intriguing electronic and magnetic properties due to strong in-plane orbital hybridization. The synthesis of this distinctive structure has primarily relied on kinetically controlled reduction of oxygen-rich phases featuring three-dimensional polyhedral oxygen coordination. Here, using in situ atomic-resolution electron microscopy, we scrutinize the intricate atomic-scale mechanisms of oxygen conduction leading to the transformation of SrFeO_2.5 to infinite-layer SrFeO₂. The oxygen release is highly anisotropic and governed by the lattice reorientation aligning the fast diffusion channels towards the outlet, which is facilitated by cooperative yet shuffle displacements of iron and oxygen ions. Accompanied with the oxygen release, the three-dimensional to two-dimensional reconfiguration of oxygen is facilitated by the lattice flexibility of FeO_x polyhedral layers, adopting multiple discrete transient states following the sequence determined by the least energy-costing pathways. Similar transformation mechanism may operate in cuprate and nickelate superconductors, which are isostructural with SrFeO₂.

Molecular electronic devices require precise control over the flow of current in single molecules. However, the electron transport properties of single molecules critically depend on dynamic molecular conformations in nanoscale junctions. Here we report a unique strategy for controlling molecular conductance using shape-persistent molecules. Chemically diverse, charged ladder molecules, synthesized via a one-pot multicomponent ladderization strategy, show a molecular conductance (d[log(G/G₀)]/dx ≈ -0.1 nm^-1) that is nearly independent of junction displacement, in stark contrast to the nanogap-dependent conductance (d[log(G/G₀)]/dx ≈ -7 nm^-1) observed for non-ladder analogues. Ladder molecules show an unusually narrow distribution of molecular conductance during dynamic junction displacement, which is attributed to the shape-persistent backbone and restricted rotation of terminal anchor groups. These principles are further extended to a butterfly-like molecule, thereby demonstrating the strategy's generality for achieving gap-independent conductance. Overall, our work provides important avenues for controlling molecular conductance using shape-persistent molecules.