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Charge-transfer emission of any type is extremely rare for coordination complexes of iron. Now, an Fe(iii) complex has been devised that shows two-colour luminescence arising from dual metal-to-ligand and ligand-to-metal charge-transfer emission.

The structural analysis of small crystals has remained challenging. Now, the structure of a small organic molecule, rhodamine-6G, has been resolved from microcrystals using an X-ray free-electron laser and electron diffraction. The former showed better reliability for atomic coordinates, whereas the latter was more sensitive to charges; both techniques accurately determined the position of hydrogen atoms.

Crystals of hexachlorobenzene have now been shown to support the autonomous motion of water and particulate matter over their surface. Parallel microchannels present at the surface of the crystal gradually widen by sublimation, propelling droplets of condensed ambient water that can also transport microscopic amounts of material such as silver microparticles.

Stereogenic sp³-hybridized carbon centres are the principal building blocks of chiral organic molecules. Usually, these centres are configurationally fixed. Now, low-energy pericyclic rearrangements have been used to create rigid cage molecules with fluxional sp³-stereochemistry, influencing chiral information transfer. The sp³-carbon stereochemistry of the cages is inverted through strain-assisted Cope rearrangements.

The molybdenum nitrogenase catalytic cofactor is composed of seven high-spin Fe sites making it difficult to study spectroscopically. Now it has been shown that ⁵⁷Fe can be incorporated into a single site and that such site-selectively labelled samples provide insights into the cofactor’s electronic structure and the mechanism of biological nitrogen fixation.

Serial rotation electron diffraction (SerialRED) enables rapid and reliable phase analysis and structure determination of complex polycrystalline materials that cannot be routinely characterized using X-ray diffraction. Five zeolite phases were identified in a single synthesis product by automated screening of hundreds of crystals, demonstrating the power of SerialRED for materials development.

The controlled functionalization of multihydrosilanes is challenging. Now, using a hydrogen-atom-transfer photocatalyst based on neutral eosin Y, a method for the diverse functionalization of hydrosilanes has been developed, enabling the stepwise on-demand decoration of silicon atoms. This approach is distinguished by its atom-, step-, redox- and catalyst-economy, metal-free nature, its versatility (>150 examples), modularity, selectivity and scalability.

The alkaloids crocagins are derived from a ribosomal peptide through a series of enzymatic post-translational modifications. A combination of biochemistry and structural biology techniques has now been used to elucidate this biosynthetic pathway, propose a mechanism for the formation of the tetracyclic core structure and enable genome mining for related natural products.

Nanomachines are central to life and are becoming an important part of self-regulated nanotechnologies. Inspired by natural self-assembled nanosystems, it has been shown that artificial nanosystems can evolve and adopt regulatory functions upon fragmentation of their structures into multiple components that reassemble to form the same nanostructure.

Aromatic polynitrogen units can display both high stability and high energy content. A hexazine anion has now been identified in a complex compound, K₉N₅₆, which is formed at high pressures and temperatures under laser-heating in a diamond anvil cell. The [N₆]⁴⁻ ring is planar and proposed to be aromatic.

Stabilization from aromatic electron delocalization is highly favourable so it is typically preserved in even grossly distorted molecules. Now, peripheral overcrowding of an aromatic tropylium has been shown to cause sufficient geometric strain to rupture aromaticity, forming a non-aromatic bicyclic system that is in rapid equilibrium with its aromatic counterpart.

The time between accepting a position as an assistant professor and taking the role is exciting and unique. But how much work is required before you even start? Shira Joudan ponders which tasks are necessary and how many times one should interrupt a very well-deserved break.

The adiabatic approximation is often applied to describe the scattering of molecules or atoms from solid surfaces. Now, unusual energy loss has been observed during the scattering of hyperthermal hydrogen atoms from a single crystalline Ge(111) surface — suggesting the existence of a non-adiabatic mechanism involving electronic interband transitions in the Ge that are induced by the hydrogen atoms.

Direct and stereospecific C(sp³)–C(sp²) cross-coupling reactions are highly desirable for the construction of complex molecular scaffolds. Now, using stable and easily accessible alkyl sulfinates as coupling reagents, a modular and programmable sulfurane-mediated coupling method has been developed for the installation of various hindered alkyl bioisosteres, such as trifluoromethyl cyclopropyl, to (hetero)aromatics.

Extensive crosslinking in thermosetting polymers provides their desirable durability but makes them difficult to recycle. Now acetal-based monomers containing nucleophilic pendant groups have been incorporated into polyurethanes, which are stable in aqueous acid yet degradable at room temperature under organic acidic conditions. The degradation products were upcycled into higher-value, long-lasting materials.

Stereochemistry can affect the reactivity and transport properties of small molecules; however, it is unclear whether the stereochemistry of components in a lipid nanoparticle influences its activity in vivo. Now, it has been shown that lipid nanoparticles made with a stereopure component can increase delivery of mRNA. A biological mechanism driving the effect is also proposed.

Kemi Oloyede reflects on the importance of having LGBTQ+ STEM events, and their role in combatting inertia in the scientific community.

Noble metals dominate the field of photosensitizers and luminophores. Now, an approach incorporating cyclometalating and carbene functions into Fe^III complexes has been shown to enable dual emission from the opposing ligand-to-metal and metal-to-ligand charge-transfer states. The latter shows an exceptionally long lifetime of 4.6 ns and is quenched by oxygen and other quenchers.

Rahul Dev Mukhopadhyay and Kimoon Kim consider how cucurbiturils — pumpkin-shaped macrocycles — went from curiosities to compelling cavitands for a host of applications.

Matthew Horwitz, creator of the Synthesis Workshop video podcast, talks to Nature Chemistry about using podcasting as a driver of professional-level education in the chemistry community.