In 1931, Erich Hückel published a landmark paper — the seed of the now famous 4n + 2 rule for aromaticity in annulenes that bears his name. Electron counting has since been extended to other classes of compounds, resulting in a multitude of rules aiming to capture the concept of aromaticity and its impact in chemistry.

In early 2020, Shira Joudan was in the final stages of her PhD when the COVID-19 pandemic hit. Despite the challenging circumstances, she graduated, found a postdoc position and will begin her independent academic career in early 2023.

The emerging field of dissipative DNA nanotechnology aims at developing synthetic devices and nanomaterials with life-like properties such as directional motion, transport, communication or adaptation. This Review surveys how dissipative DNA systems combine the programmability of nucleic-acid reactions with the consumption of energy stored in chemical fuel molecules to perform work and cyclical tasks.

The tris(2,2′-bipyridine)ruthenium(II) cation, or ‘rubipy’ to its friends, has had a significant influence on our understanding of the photophysics of transition metal complexes, and has also helped revolutionize organic photochemistry, explains Daniela M. Arias-Rotondo.

Nucleotides are essential to the origins of life, and their synthesis is a key challenge for prebiotic chemistry. Contrary to prior expectation, non-canonical 3′-amino-TNA nucleosides are shown to be synthesized diastereoselectively and regiospecifically under prebiotically plausible conditions. The enhanced reactivity of 3′-amino-TNAs also promotes their selective non-enzymatic triphosphorylation in water.

The biochemical roles and mechanisms of multiphase membraneless organelles are not yet well understood. Now, multiphase peptide droplets have been shown to sort RNA based on whether it is single- or double-stranded, as well as impact RNA duplexation through in-droplet thermodynamic equilibria. This work provides insight into possible primitive mechanisms for multicompartment intracellular condensates and can aid in the design of functional artificial membraneless organelles.

Ions in salt solutions perturb the hydrogen bonding between the surrounding water molecules, altering the properties of water, but how ion polarity affects this is not fully understood. By monitoring the dissipation of terahertz energy in salt solutions, it has now been shown that intermolecular rotational-to-translational energy transfer is enhanced by highly charged cations and reduced by highly charged anions.

Despite mechanically axially chiral (MAC) catenanes being recognized in 1961, their stereoselective synthesis had not been disclosed until now. Closer inspection of the MAC stereogenic unit has also led to the identification of an analogous, but unremarked upon, form of rotaxane stereochemistry and the conceptualization of a general approach to prepare MAC molecules stereoselectively.

The strained topology of [n]paracyclophenylenes ([n]CPPs) typically prevents their π sysytem from being extended, but now the formation of a planar π-extended CPP has been achieved through a bottom-up on-surface synthesis approach. The planar π-extended [12]CPP produced by this method is a nanographene featuring an all-armchair edge, which leads to delocalized electronic states around the entire ring.

The direct copolymerization of carbon dioxide and commodity olefins has been a long-standing challenge in polymer science. Now, an indirect approach has been developed in which hydrogenated disubstituted valerolactones derived from telomerization of CO₂ and butadiene can undergo ring-opening polymerization, yielding chemically recyclable and degradable aliphatic polyesters with high CO₂ content.

Choline 2-hexenoate is an ionic compound that is a liquid at room temperature, and is just one of a class of compounds that have huge potential in biomedical research and clinical applications, explains Eden E. L. Tanner.

Michelle Francl explores how glass revolutionized chemistry.

The tris(2,2′-bipyridine)ruthenium(II) cation, or ‘rubipy’ to its friends, has had a significant influence on our understanding of the photophysics of transition metal complexes, and has also helped revolutionize organic photochemistry, explains Daniela M. Arias-Rotondo.

In early 2020, Shira Joudan was in the final stages of her PhD when the COVID-19 pandemic hit. Despite the challenging circumstances, she graduated, found a postdoc position and will begin her independent academic career in early 2023.

In 1931, Erich Hückel published a landmark paper — the seed of the now famous 4n + 2 rule for aromaticity in annulenes that bears his name. Electron counting has since been extended to other classes of compounds, resulting in a multitude of rules aiming to capture the concept of aromaticity and its impact in chemistry.

In 2017 Professor Frances S. Ligler was inducted into the National Inventors Hall of Fame for her inventions in portable optical biosensors. Professor Ligler now talks to Nature Chemistry about the challenge of developing new sensor designs into reliable products, and some of the pitfalls to avoid in the development process.