Volume 16 Issue 1, January 2024

As the need for specific fluorescent probes that enable high sensitivity and super-resolution imaging experiments continues to grow, it is imperative to develop new, well-characterized methods to modulate the emission of fluorophores. Now, a general platform affords visible-to-NIR fluorogenic fluorophores by engineering a simple cyclization event into cyanine dyes.

The study of disordered materials poses numerous challenges, and computational approaches have proved useful to supplement and support structural experiments. Now, an abstract computational model has been used to study the structure of amorphous calcium carbonate, providing mechanistic insights into the emergence of the disordered phase as well as its atomic-level configurations.

Tetracoordinate boron molecules are the key intermediates in many organoboron-related chemical transformations. Now, using alkynyl tetracoordinate boron species, a nickel-catalysed asymmetric 1,3-metallate shift towards axial chirality has been developed, giving access to various axially chiral alkenes in high efficiency.

Liquid–liquid phase separation (LLPS) within cells is a captivating phenomenon known to aid the organization of cellular components; however, its complex kinetics have remained a puzzle. Now, a new study elucidates the crosstalk between the phase state of an encapsulating membrane and LLPS dynamics.

The self-assembly of stimuli-responsive building blocks yields functional nano-systems and smart materials. This Perspective discusses how the integration of photoswitches into discrete coordination cages enables control over their assembly, guest binding and systems behaviour. Four scenarios are drawn to highlight the relationship between the photoswitching and dynamic assembly equilibria.

The prototypical trans–cis photoisomerization of stilbenes is thought to occur via a transient intermediate with a perpendicular conformation—often called ‘the phantom state’—but its unambiguous identification has thus far proved difficult. Now, using ultrafast ultraviolet Raman spectroscopy and ab initio molecular dynamics simulation, evidence for its existence and its perpendicular conformation has been obtained.

Polymethine dyes are bright and red-shifted fluorophores that lack an intrinsic turn-on mechanism, which leads to non-specific staining when applied to biological samples. Now the fluorescence of polymethine dyes was masked through an intracellular cyclization strategy that gets reversed upon binding an intended macromolecular target, providing specificity for live-cell imaging.

Although amorphous calcium carbonate represents an important biomineralization precursor, its structure has been difficult to understand. Now, amorphous calcium carbonate’s structure is shown to arise from the different bridging modes available to the calcium ions. This effective multi-well potential that drives calcium arrangements creates a geometric incompatibility between preferred Ca–Ca distances and frustrates crystallization.

Enantioselective transformations based on tetracoordinate borons are elusive. Now, an enantioselective nickel-catalysed strategy for the construction of axially chiral alkenes has been reported, via a 1,3-metallate shift of alkynyl tetracoordinate boron species. The reaction uses readily accessible starting materials and a cheap transition-metal catalyst, and the chemoselectivity, regioselectivity and atroposelectivity could be well controlled.

The kinetics of liquid–liquid phase separation (LLPS) in cell-like confinements remains poorly understood. Now it has been shown that it involves complex interplay between the incipient phases and the membrane boundary, which arrests phase coarsening, deforms the membrane and couples LLPS with lipid phase separation.

The reversible N–H activation and catalytic transformations of ammonia are a challenge. Now, a hidden frustrated Lewis pair is shown to activate non-aqueous ammonia thermoneutrally and split the N–H bond reversibly at ambient temperature. The N–H-activated ammonia was also utilized as an atom-economical nitrogen source for catalytic NH₃ transfer reactions.

The coupling of autocatalysis to compartment growth and division is a key step in the origin of life. Now it has been shown that compartmentalizing the formose reaction in emulsion droplets leads to several crucial properties of living and evolving systems (growth, division, variation, competition, rudimentary heredity and selection).

The onset of eco-evolutionary dynamics marks a stepping stone in the transition from chemistry to biology. Now a minimal replicator system showing such dynamics has been developed. The replicators adapt to changes in their environment that they themselves induced through photoredox catalysis.

Phase separation is being revealed as important in many biological processes. Most attempts to mimic and deconstruct this use engineered natural proteins. Now it is shown that de novo proteins can be designed from first principles to undergo liquid–liquid phase separation in cells, with the potential to organize multi-enzyme pathways.

Although exciplex-forming systems are widely used for fabricating organic light-emitting diodes (OLEDs), their structural and thermodynamic characterization is limited. Now donor/acceptor inclusion complexes that demonstrate thermally activated delayed fluorescence have been generated. Their cocrystal structures have been resolved and the thermodynamics of exciplex formation determined, which has enabled the fabrication of efficient OLEDs.

Merging carbonyls to form an alkene by removing their oxygens is rare, yet synthetically useful, and the selective combination of two different carbonyls is especially challenging. Now, two strategies for cross-metathesis of unbiased carbonyls have been developed. An Fe-catalysed carbene/ylide strategy affords Z-alkenes, while Cr-catalysed gem-di-metals yield E-alkenes.

Covalent organic frameworks offer a highly tunable class of materials for a range of applications, although their dynamic structural transformations are challenging to analyse. Now single-crystal X-ray diffraction is shown to demonstrate single-crystal-to-single-crystal transformations of the imine linkages, showing a well-defined interpenetrating topology and affording structures that have high positive thermal expansion and anhydrous proton-conduction properties.

The discovery of biomarkers remains challenging owing to a lack of methods sensitive enough to identify such rare molecules. Now, by simultaneously exploiting the catalysis and affinity of a DNAzyme, candidate biomarkers with low abundance in cancers can be pulled down for identification and validation.

The synthesis of optically enriched atropisomers has so far been limited to molecules containing aryl groups. Now a variant of non-aryl atropisomerism has been identified in vinyl sulfoxonium ylides, and an organocatalytic method has been developed to produce these molecules. This type of axial chirality is characterized by restricted rotation of the central C(sp²)–C(sp²) bond.

Dewran Kocak and Bryan Roth discuss a psychedelic — 5-MeO-DMT — and what we might learn from its properties.