Nature chemistry最新文献

Correction to: Nature Chemistry https://doi.org/10.1038/s41557-023-01211-3, published online 1 June 2023.

Correction to: Nature Chemistry https://doi.org/10.1038/s41557-023-01212-2, published online 15 May 2023.

Alkenes are broadly used in synthetic applications, thanks to their abundance and versatility. Ozonolysis is one of the most canonical transformations that converts alkenes into molecules bearing carbon–oxygen motifs via C=C bond cleavage. Despite its extensive use in both industrial and laboratory settings, the aza version—cleavage of alkenes to form carbon–nitrogen bonds—remains elusive. Here we report the conversion of alkenes into valuable amines via complete C=C bond disconnection. This process, which we have termed ‘triazenolysis’, is initiated by a (3 + 2) cycloaddition of triazadienium cation to an alkene. The triazolinium salt formed accepts hydride from borohydride anion and spontaneously decomposes to create new C–N motifs upon further reduction. The developed reaction is applicable to a broad range of cyclic alkenes to produce diamines, while various acyclic C=C bonds may be broken to generate two separate amine units. Computational analysis provides insights into the mechanism, including identification of the key step and elucidating the significance of Lewis acid catalysis.

The photomodulation of the helical pitch of cholesteric liquid crystals results in dynamic and coloured canvases that can potentially be used in applications ranging from energy-efficient displays to colour filters, anti-counterfeiting tags and liquid crystal (LC) lasers. Here we report on the analysis of a series of photoswitchable chiral dopants that combine the large geometrical change and bistability of hydrazone switches with the efficient helical pitch induction of the chiral motif, triptycene. We elucidate the effects that conformational flexibility, dispersion forces and π–π interactions have on the chirality transfer ability of the dopant. We then use the irradiation time with visible light (442 nm) combined with a simple digital light processing microscope projection set-up to draw numerous stable multi-coloured images on an LC canvas, showcasing the fine control this dopant yields over the LC assembly.

Molecular catalysts offer tunable active and peripheral sites, rendering them ideal model systems to explore fundamental concepts in catalysis. However, hydrophobic designs are often regarded as detrimental for dissolution in aqueous electrolytes. Here we show that established cobalt terpyridine catalysts modified with hydrophobic perfluorinated alkyl side chains can assemble at the gas–liquid–solid interfaces on a gas diffusion electrode. We find that the self-assembly of these perfluorinated units on the electrode surface results in a catalytic system selective for electrochemical CO₂ reduction to CH₄, whereas every other cobalt terpyridine catalyst reported previously was only selective for CO or formate. Mechanistic investigations suggest that the pyridine units function as proton shuttles that deliver protons to the dynamic hydrophobic pocket in which CO₂ reduction takes place. Finally, integration with fluorinated carbon nanotubes as a hydrophobic conductive scaffold leads to a Faradaic efficiency for CH₄ production above 80% at rates above 10 mA cm⁻²—impressive activities for a molecular electrocatalytic system.