In this issue we feature several articles that explore advances in the study of phase separation. They highlight some recently reported mechanistic features and progress in the methodology used to study it within cells, and they delve into the implications that phase separation has for select cellular functions.

Liquid droplets form in cells to concentrate specific biomolecules (while excluding others) in order to perform specific functions. The molecular mechanisms that determine whether different macromolecules undergo co-partitioning or exclusion has so far remained elusive. Now, two studies uncover key principles underlying this selectivity.

Tanja Mittag talks to Nature Chemistry about how her path in research led to her work in phase separation and her thoughts about the future of the field.

A. Ken Inge pores over the history and applications of bismuth subsalicylate, from dispelling digestive distress to breaching bacterial biodefences.

The ligandability of the human proteome can be expanded using covalent chemistry. A multi-tiered chemical proteomic strategy now provides in-depth maps of tryptoline acrylamide–protein interactions in cancer cells. This platform afforded the discovery of stereoselective covalent ligands for hundreds of human proteins, including compounds that disrupt protein–protein interactions regulating the cell cycle.

Solar water splitting holds great promise for hydrogen production but is significantly hindered by rapid recombination of photogenerated charges. Now a metal–organic framework photocatalyst has been shown to undergo, upon photoexcitation, a dynamic excited-state structural twist that greatly suppresses charge recombination to enable efficient photocatalytic overall water splitting.

The scalable, energy-efficient and environmentally friendly production of solid-state materials is crucial for next-generation material synthesis. Now an efficient and gram-scale synthesis of transition metal dichalcogenides, group XIV dichalcogenides and non-transition metal dichalcogenides has been achieved using the flash-within-flash heating technique, a non-equilibrium, ultrafast heat conduction method.

Although strategies to stabilize the singlet state of carbenes are known, obtaining stable triplet electromers remains a challenge. Now it has been shown that transition-metal substitution enables the generation of triplet metallocarbenes stabilized by spin-polarized push–pull interactions; these compounds exhibit appreciable lifetimes beyond cryogenic temperatures.

Cross-coupling reactions are among the most important carbon–carbon bond-forming reactions. Now the nickel-catalysed cross-coupling of chiral sulfones with Grignard reagents has been achieved with up to 99% retention of chirality. The speed of the cross-coupling relative to sulfone deprotonation and racemization is critical to enabling this enantiospecific process.

Tryptophan plays important biological roles in aromatic cages, such as methyllysine recognition, but the development of site-selective crosslinking to tryptophan is challenging. Now sulfonium can be used as a methyllysine mimic that binds to reader proteins and crosslinks tryptophan inside a pocket through single-electron transfer. This strategy enables the identification of methyllysine readers from the proteome.

Nitric oxide is at the heart of myriad environmental and biological processes. Pokhraj Ghosh and Timothy Warren explore the molecular interconnections and wide-ranging impacts of this molecule which is critical for the health of our planet.

In his previous Thesis, Bruce Gibb introduced us to the chemistry of Jupiter’s moons. Now, he takes us on a tour of NASA’s Europa Clipper, the spacefaring chemistry lab set to revolutionize our understanding of Jupiter’s most intriguing satellite.

In this issue we feature several articles that explore advances in the study of phase separation. They highlight some recently reported mechanistic features and progress in the methodology used to study it within cells, and they delve into the implications that phase separation has for select cellular functions.

A. Ken Inge pores over the history and applications of bismuth subsalicylate, from dispelling digestive distress to breaching bacterial biodefences.

Tanja Mittag talks to Nature Chemistry about how her path in research led to her work in phase separation and her thoughts about the future of the field.

In molecular biology, few molecules have had as profound an impact as Cas9. Madeleine King, Kayla Perry, Mitchell McAndrew and Audrone Lapinaite discuss how this multifunctional molecular tool of genetic engineering is revolutionizing multiple fields.