Volume 15 Issue 4, April 2023

Zafra Lerman talks to Nature Chemistry about embedding art in science education, and science in the pursuit of peace on Earth.

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.

Plasmonic heating by nanoparticles has been used to promote a range of chemical reactions. Now, thermoplasmonic activation has been applied to latent ruthenium catalysts, enabling olefin metathesis initiated by visible and infrared light.

Therapies that destroy senescent cells could be used to alleviate age-related disease, yet conventional drugs often suffer from low selectivity and unwanted side effects. Now, a photosensitive agent has been developed that is activated in situ in senescent cells, enabling their selective elimination.

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.

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 advantages and disadvantages of building a nanosystem using one, two or more molecular components are poorly understood. Now, using structural and catalytic DNA-based nanosystems and theoretical simulations, it has been shown that the assembly of trimeric nanosystems displays much higher levels of programmability and functionality than the monomeric or dimeric counterparts.

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.

Current strategies for photoinduced olefin metathesis lack wavelength tunability. Now, plasmonic nanoparticles have been used to activate latent ruthenium catalysts, enabling light-induced olefin metathesis in the infrared range with several advantages when compared with conventional heating. Implementing this approach in ring-opening metathesis polymerization resulted in photoresponsive polymer–nanoparticle composites with enhanced mechanical properties.

X-ray diffraction is crucial for the phase elucidation of polycrystalline materials but remains challenging for complex multiphase systems. Now serial rotation electron diffraction has been shown to enable rapid, reliable and semiquantitative phase analysis of such systems, facilitating high-throughput screening of complex synthesis systems and providing new opportunities for materials development.

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.

Controlling various selectivities in radical reactions presents both formidable challenges and great opportunities. Now, Co(II)-based metalloradical catalysis has enabled the concurrent control of multiple convergences and selectivities in intermolecular radical allylic C−H amination. The reaction provides access to valuable chiral α-tertiary amines directly from an isomeric mixture of alkenes.

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.

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.

A Diels–Alderase that catalyses the inherently disfavoured cycloaddition and forms a bicyclo[2.2.2]diazaoctane scaffold with a strict α-anti-selectivity has now been discovered. This Diels–Alderase, called CtdP, is an NmrA-like protein. Isotopic labelling, structural biology and computational studies reveal that the CtdP-catalysed Diels–Alder reaction involves a NADP⁺/NADPH-dependent redox mechanism.

Substituted bicyclo[2.1.1]hexanes (BCHs) are emerging bicyclic hydrocarbon bioisosteres for ortho- and meta-substituted benzenes, but are difficult to access. Now a SmI₂-catalysed intermolecular coupling of bicyclo[1.1.0]butyl ketones and alkenes provides a general approach to access substituted BCHs, thus promoting their widespread use in medicinal chemistry and crop science.

Sorbent materials that reversibly transform between closed (non-porous) and open (porous) phases on the uptake and release of guests are relevant to gas storage and separation applications. Now, a coordination network has been prepared that exhibits gas-induced transformations between multiple non-porous phases. This phenomenon is attributed to subtle structural rearrangements that enable transient porosity.

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.

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.

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.

A nanopore framework has been developed to reveal the crosstalk effect on the renin–angiotensin system. By reading the single-amino-acid differences in angiotensin peptides with high accuracy and high efficiency, the selective inhibition of angiotensin-converting enzyme by angiotensin-converting enzyme 2 was revealed. This activity was shown to be suppressed by the spike protein of SARS-CoV-2.

Jane Liao and Allie C. Obermeyer explore the discovery, modification and applications of green fluorescent protein, best known for its use as a tool to cast light on cellular processes.