To understand why the committee’s citation matters, it helps to begin with chirality, the phenomenon at the heart of the award. Many molecules exist in two forms that are mirror images of one another, much like a pair of hands: they share the same atoms and the same connections, yet they cannot be superimposed on one another. Chemists call these two forms enantiomers. In a flask of ordinary reagents, a reaction that creates a new chiral center typically produces both forms in equal amounts, yielding a racemic mixture with no net handedness. Living systems, however, are strikingly selective. The amino acids that build proteins, the sugars that carry genetic information, and the receptors that drugs must engage are all handed, and a molecule of the wrong handedness can be inert at best and harmful at worst.

Asymmetric synthesis is the branch of chemistry devoted to this selectivity problem: how to persuade a reaction to form one enantiomer preferentially over the other. For decades, chemists achieved this with chiral catalysts and auxiliaries, molecular scaffolds that bias the transition state of a reaction toward one geometry. The efficiency of such processes is usually described by enantiomeric excess, a measure of how much one mirror-image form dominates the mixture. What Kagan recognized, and what the Nobel committee’s phrase non-linear effects captures, is that the relationship between the purity of a chiral catalyst and the purity of the product it delivers is not always the straightforward, proportional one that simple models predict.

In a linear world, a catalyst that is eighty percent enantiopure would be expected to give a product whose enantiomeric excess scales in a simple, predictable way with that purity. Kagan’s work revealed that in many asymmetric reactions the outcome depends on the catalyst’s handedness in a decidedly non-linear fashion. Small differences in catalyst purity can be magnified into large differences in product selectivity, or in some regimes, damped. This insight forced a rethinking of how chiral catalysts operate at the mechanistic level. It showed that aggregates of catalyst molecules, dimers and higher assemblies, can act in concert, and that the details of how catalyst molecules pair up can dominate the stereochemical outcome of a reaction. For chemists designing syntheses of complex, handed molecules, this was a practical warning and an opportunity at once: the enantiomeric purity of a catalyst is not just a starting condition but an active variable that can be exploited.

Soai’s contribution, honored under the second half of the citation, pushed these ideas into even more remarkable territory. Autocatalysis refers to a process in which a reaction’s product acts as a catalyst for its own formation, so that the product accelerates the very chemistry that produces it. Soai demonstrated that in certain asymmetric reactions, molecules of one handedness can amplify their own dominance: a tiny initial imbalance between the two enantiomers, far too small to measure by ordinary means, can grow through successive catalytic cycles into a mixture that is overwhelmingly one handed. The phenomenon, known as asymmetric autocatalysis with amplification of enantiomeric excess, provides a chemical route by which near-perfect molecular handedness can emerge from essentially symmetric beginnings.

The implications of that finding extend well beyond the synthetic laboratory. One of the enduring puzzles in the origin of life is homochirality, the question of why biology uses almost exclusively left-handed amino acids and right-handed sugars when both mirror-image forms are chemically plausible. A mechanism by which a vanishingly small initial bias, perhaps imparted by circularly polarized light or some other subtle physical influence, could be amplified to biological levels of purity has long been sought. Soai’s autocatalytic systems offered chemists a concrete, reproducible model of how such amplification might operate, turning a philosophical puzzle into an experimental science. The same chemistry also serves as an exquisitely sensitive probe, capable of revealing chiral influences so weak that conventional instruments cannot detect them directly.

Hernandez, in his statement on behalf of the American Chemical Society, framed the laureates’ achievement in vivid terms. Kagan and Soai led the way in dreaming and making new ways to control molecular handedness with remarkable precision, he said. Kagan helped establish the principles for producing one molecular form with extraordinary selectivity, while Soai revealed the remarkable phenomenon that such molecules can amplify their own handedness. Just like dancing partners must match, chemistry depends on molecules coming together in the right way. Their discoveries gave chemists unprecedented control over that process, enabling advances in medicines, materials, and so much more. The metaphor of dancing partners captures a deep truth about molecular recognition: biological and synthetic systems alike depend on shapes fitting together in specific three-dimensional arrangements, and control over handedness is control over that fitting.

The practical consequences of this control are visible throughout modern chemistry and medicine. Pharmaceutical molecules frequently contain one or more chiral centers, and regulatory science has long recognized that the two enantiomers of a drug can differ in potency, metabolism, and safety. Synthetic routes informed by the principles Kagan established allow manufacturers to produce the desired single enantiomer with high efficiency, reducing waste and improving the therapeutic profile of medicines. In materials science, chiral molecules underpin technologies from liquid crystal displays to optical devices that interact differently with left- and right-circularly polarized light. The non-linear effects that Kagan characterized inform how chemists choose, prepare, and deploy their catalysts, while autocatalytic amplification offers strategies for achieving extreme enantiopurity from modest starting materials.

The laureates’ connection to the American Chemical Society runs deep, and the society’s statement emphasized that history. Kagan has been an ACS member for sixty years, and Soai was an ACS member for twenty-six years and remains part of the ACS member community. The seminal papers recognized by the Nobel committee were published in the Journal of the American Chemical Society and in ACS’ Accounts of Chemical Research, two of the most widely read journals in the field. Kagan and Soai have published additional work on homochirality across ACS’ portfolio of more than ninety peer-reviewed journals, and both have been featured in Chemical & Engineering News, the society’s news outlet. Articles from that body of work are available to journalists upon request, a resource likely to see heavy use as the chemistry community digests the award.

For the broader public, the prize is an invitation to appreciate a kind of chemistry that operates at a scale far below the reach of the eye but with consequences that reach every medicine cabinet and every living cell. The ability to make a molecule in one handed form rather than a fifty-fifty mixture is the difference between a precise tool and a blunt instrument, and the discoveries honored this year explain both how to achieve that precision and how nature might have achieved it first. The ACS will post a special Headline Science short video about the Nobel Prize in Chemistry, and news media can arrange interviews with Hernandez or other experts in the field through the ACS Newsroom. As the celebrations begin in Orsay and Tokyo, the award stands as a reminder that some of the most consequential questions in science, including why life chose one hand over the other, can be answered molecule by molecule, in flasks and catalysts, by chemists patient enough to ask them.

Subject of Research: Non-linear effects and autocatalysis in asymmetric organic synthesis, recognized by the 2026 Nobel Prize in Chemistry

Article Title: ACS president comments on award of 2026 Nobel Prize in Chemistry

Article References: ACS president comments on award of 2026 Nobel Prize in Chemistry. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: Nobel Prize in Chemistry, asymmetric synthesis, chirality, autocatalysis, non-linear effects, enantiomeric excess, homochirality, Henri Kagan, Kensō Soai, American Chemical Society, molecular handedness, chiral catalysis

The scientific logic behind the technique rests on one of the strangest asymmetries in biology. Amino acids, the building blocks of proteins, come in two mirror-image forms, conventionally labeled L and D. Chemically, the two forms are nearly identical: they share the same molecular formula, the same mass, and the same bonds, differing only in the way they rotate polarized light and in the three-dimensional arrangement of their atoms. Yet life on Earth is strikingly selective. Nearly every amino acid incorporated into proteins is the L-form, while the sugars that make up DNA and RNA are almost exclusively the D-form. Nonliving chemistry, by contrast, whether in a laboratory flask or in the deep interior of an asteroid, produces L- and D-forms in equal quantities. This imbalance, quantified as the L/D ratio, is therefore considered one of the most robust potential biosignatures available to astrobiologists, because it is difficult to imagine a purely abiotic process that would generate it on a planetary scale.

Traditional methods for measuring that ratio, such as chromatographic separation followed by mass spectrometry, work by sorting large ensembles of molecules and inferring composition from bulk behavior. These techniques are exquisitely sensitive, but they demand substantial laboratory infrastructure: gas or liquid chromatography systems, high vacuum chambers, and quantities of chemical reagents that must be carried aboard any spacecraft. Each of these requirements adds mass, complexity, and failure modes to a mission payload. The Osaka team, led by first author Takahito Oshiro and senior author Masateru Taniguchi, pursued an alternative vision in which detection would be electrical, compact, and reagent-free, relying instead on the quantum mechanical phenomenon of electron tunneling.

The core of the device is a pair of gold nanowires separated by a gap so small that only a single molecule can bridge it at a time. When an amino acid molecule enters the gap, electrons can tunnel quantum-mechanically from one wire to the other through the molecule, producing a measurable electrical current. Crucially, that current is not a constant value but a fluctuating waveform whose shape depends on the molecule’s structure, orientation, and electronic properties as it interacts with the electrodes. Because the L- and D-forms of an amino acid present mirror-image geometries to the nanogap, their tunneling waveforms differ in ways that are subtle but consistent. By recording thousands of these single-molecule events and training machine-learning algorithms on the resulting data, the researchers could classify each transient event as belonging to one handedness or the other, effectively counting molecules of each form one by one.

According to the team, this is the first time amino acid chirality has been discriminated at the single-molecule level, a milestone Oshiro describes as a fundamental advance in chemical sensing. The claim matters because single-molecule detection carries advantages that bulk measurements cannot match. It requires no labels, no derivatizing agents, and no prior separation of the sample into its components. It is also, as the researchers note, less sensitive to mechanical vibration than many optical or chromatographic approaches, an important consideration for instruments that must survive launch stresses and operate on the surface of another world. The electronics involved are, in principle, miniaturizable to chip scale, opening a path toward compact astrobiology payloads that could fly on landers, rovers, or even small probes.

A single-molecule sensor, however, is only useful for astrobiology if it can cope with the messy reality of extraterrestrial samples. Real planetary materials do not arrive as purified solutions of one amino acid; they contain complex mixtures of organic compounds, salts, and minerals, many of which could generate tunneling signals of their own. To test the technique against this complexity, the team analyzed natural samples from two of the most celebrated sources in astrobiology: the Murchison meteorite, a carbon-rich meteorite that fell in Australia in 1969 and is famous for containing a rich inventory of prebiotic organic molecules, and soil collected from the hyperarid core of the Atacama Desert in Chile, one of the driest environments on Earth and a standard Mars-analog site used to test life-detection instruments under conditions of extreme desiccation and intense ultraviolet radiation.

The results were encouraging. When the nanogap measurements were compared with conventional analytical methods applied to the same extracts, the two approaches captured the major features of the amino acid composition in agreement. In other words, the electrical technique did not merely detect that amino acids were present; it recovered a recognizable profile of which amino acids were there and in what relative abundances, despite the chemical complexity of the starting material. Taniguchi emphasizes that this comparability with established methods is what elevates the work from a laboratory curiosity to a candidate technology for real missions, since any new instrument must ultimately reproduce the findings of the mature techniques it hopes to complement or replace.

The implications extend across several domains of planetary science. For Mars, where rovers have already found organic molecules in ancient rocks but cannot yet determine whether those organics carry biological or abiotic origins, a compact chirality sensor could provide a decisive second opinion. A clear enantiomeric excess of L-amino acids in a Martian sample would be far harder to explain through known nonbiological chemistry than the mere presence of organics. For the icy moons of the outer solar system, such as Europa and Enceladus, where plumes of subsurface ocean material could be sampled by flyby spacecraft, mass and power budgets are even tighter, making reagent-free electrical detection especially attractive. The same technology could also benefit terrestrial applications, from contamination monitoring in cleanrooms used to handle planetary protection samples to rapid analysis in environmental and biomedical laboratories.

Significant engineering hurdles remain before such an instrument flies. The published accuracy of over 80 percent for chirality discrimination, while a proof of principle, would need to improve for quantitative L/D measurements on mission-critical decisions, and the machine-learning classifiers must generalize to amino acids and mixtures not represented in their training data. Nanogap electrodes must also maintain their atomic-scale spacing through temperature swings, radiation exposure, and years of dormancy during interplanetary cruise. The Osaka team’s demonstration, however, establishes that the physics works on real, complex, natural samples rather than idealized laboratory solutions. By showing that a molecule’s handedness can be read out as an electrical waveform, one molecule at a time, the researchers have added a promising new tool to the astrobiology toolkit, one that brings the dream of a shoebox-sized life detector a measurable step closer to reality.

Subject of Research: Single-molecule electrical detection of amino acid chirality as a biosignature technique for astrobiology

Article Title: An electrical technique for identifying signs of life in space

Article References: An electrical technique for identifying signs of life in space. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: astrobiology, biosignatures, amino acids, chirality, nanogap tunneling, single-molecule detection, Murchison meteorite, Atacama Desert, artificial intelligence, nanotechnology, Nature Communications, space instrumentation

The researchers show that when an oddly shaped cavity is carved out of a hyperbolic metamaterial, the chaotic dynamics that would normally dominate its wave motion are suppressed and replaced by something far more orderly: robust, geometrically organized wave patterns the team calls hyperbolic wave attractors. These states are chiral, meaning they carry a handedness, and they are broadband and scale-invariant, properties that set them apart from both the resonant modes of conventional cavities and the erratic eigenmodes of chaotic ones. In the language of nonlinear dynamics, they organize wave motion in a manner analogous to limit cycles, the stable closed trajectories toward which dissipative systems evolve regardless of where they start. Remarkably, the entire phenomenon unfolds in a fully linear system, with no nonlinear feedback required to stabilize the motion.

To understand why hyperbolic media can impose this order, it helps to consider how waves behave inside them. In an ordinary isotropic material, the relationship between frequency and wave vector, the dispersion relation, forms a closed spherical or circular surface, and waves of essentially all propagation directions carry energy outward from a source. In a hyperbolic metamaterial, by contrast, the principal components of the material tensor have opposite signs, so the isofrequency surface opens up into a hyperboloid. Waves propagating in such a medium obey a fixed geometric rule: the group velocity, which determines the direction of energy flow, is constrained to a narrow cone of angles relative to the material’s principal axis, no matter how the wave is launched. This rigidity of propagation angle is the crucial ingredient, because it makes reflections behave in a fundamentally different way than they do in isotropic media.

The concept of wave attractors is not entirely new to physics. Oceanographers studying internal waves, the slow oscillations that travel through the stably stratified depths of the sea, discovered decades ago that these waves also propagate at fixed angles set by the stratification and the tidal forcing frequency. When such waves slosh inside a closed basin with sloping walls, their ray trajectories are funneled, bounce after bounce, onto a single closed path that the entire wave field concentrates upon, an attractor in the strict dynamical sense. Leo Maas and colleagues observed one of these attractors experimentally in a confined stratified fluid in 1997, and subsequent theoretical work established the mathematical framework for attractors of waves with homogeneous dispersion relations. What the new study demonstrates is that artificial hyperbolic media reproduce precisely this geometry-controlled physics in an engineered, solid-state platform, where it can be exploited rather than merely observed.

The experimental realization relied on elastodynamic waves, mechanical vibrations traveling through a solid hyperbolic metamaterial. The team constructed a metasurface, an engineered structure whose architecture endows it with the anisotropic, opposite-sign tensor properties required for hyperbolic propagation, and shaped it into irregular, oddly outlined cavities that would have produced thoroughly chaotic dynamics in any conventional material. When waves were launched inside, the expected chaos never materialized. Instead, the wave energy converged onto stable attractor patterns, tracing closed chiral loops through the cavity that remained consistent across repeated trials and across a broad band of excitation frequencies. Because the attractors organize ray motion geometrically rather than through wavelength-scale interference, they persist across scales, a scale invariance that conventional resonant cavities, whose modes are locked to specific dimensions and frequencies, cannot match.

The researchers mapped the phenomenon in detail, revealing features that connect it to the broader taxonomy of dynamical systems. Their bifurcation analysis shows that hyperbolic wave attractors undergo phase transitions as the cavity geometry or excitation conditions are varied: the attractor paths reorganize abruptly, switching between distinct topological configurations in much the same way that nonlinear oscillators pass through bifurcations. The team also identified symmetry-driven features in the attractor patterns, showing how the simultaneous breaking of symmetry in both the material response and the cavity boundary cooperates to select the handedness of the emerging chiral states. Because two rays traveling in opposite directions along an attractor trace mirror-image loops, the cavity naturally supports waves of definite chirality, a property usually associated with sophisticated chiral resonators or systems operating near exceptional points.

Perhaps the most practically significant finding is robustness. Chaotic cavities are notoriously sensitive: a small defect in the boundary, a slight perturbation in the medium, or a tiny shift in frequency scrambles the entire field pattern. The hyperbolic wave attractors proved strikingly resistant to such perturbations. The team demonstrated experimentally that even in the presence of defects, the wave field continued to organize itself onto the attractor, converging back onto the same geometric paths. This stability, inherited from the attractor’s role as a dynamical fixed point rather than a delicate interference condition, is precisely what makes the concept attractive for real-world devices, where fabrication tolerances and environmental drift inevitably spoil idealized designs.

The applications the authors envision follow directly from merging two capabilities that normally require very different structures. The attractor states combine functionalities traditionally associated with large, wavelength-scale structures with those of deeply subwavelength cavities, opening possibilities for compact, multifunctional components in wave-based signal processing and sensing. As a proof of concept, the team demonstrated an attractor metasurface capable of frequency sorting, routing different frequency components of a broadband signal to different spatial locations on the basis of the attractor dynamics. Because the effect is broadband and scale-invariant, such components could in principle be made far more compact than conventional wavelength demultiplexers, which typically rely on extended interferometric or resonant structures. The same robustness that protects the attractor against defects also suggests uses in sensing, where a stable reference pattern that responds reproducibly to perturbations is a valuable asset.

The work also resonates with a wider scientific conversation about order emerging from wave chaos. In quantum and optical systems, researchers have long studied scars, the curious tendency of chaotic wavefunctions to concentrate along unstable periodic orbits of the underlying classical dynamics, a phenomenon first predicted by Eric Heller in 1984 and recently visualized directly in graphene quantum dots. Hyperbolic wave attractors occupy a distinct and arguably more useful niche: where scars are fragile remnants of unstable orbits, attractors are stable sinks toward which all trajectories converge, and where scars inherit their geometry from the cavity alone, hyperbolic attractors draw it from the interplay of cavity and medium. Because the same attractor physics extends across natural and artificial hyperbolic media, from stratified fluids to engineered metamaterials and van der Waals crystals supporting hyperbolic polaritons, the framework the New York team has established could guide wave control in platforms ranging from acoustic devices to nanoscale optical circuits, all without a single nonlinear element.

Subject of Research: Taming wave chaos in irregular cavities using hyperbolic metamaterials that produce stable chiral wave attractors

Article Title: Hyperbolic wave attractors

Article References: Yves, S., Renzi, E. M., Mann, S. A., & Alù, A. (2026). Hyperbolic wave attractors. Nature Physics. https://doi.org/10.1038/s41567-026-03453-7

Image Credits: AI Generated

DOI: 10.1038/s41567-026-03453-7

Keywords: hyperbolic metamaterials, wave chaos, wave attractors, cavity physics, metasurfaces, elastodynamic waves, chirality, bifurcation, scale invariance, signal processing, sensing, Nature Physics

Chirality, the property of an object that cannot be superimposed on its mirror image, is usually associated with the handedness of molecules such as amino acids or DNA. Pasteur famously separated the left- and right-handed crystals of tartaric acid in 1848, and chemists have long known that achiral molecules can occasionally crystallize into chiral forms. But deliberate, controllable twisting in inorganic crystals remains rare, and in layered materials it is rarer still. Previous examples have relied on screw dislocations, which impose an Eshelby twist on growing whiskers, or on growth on curved, non-Euclidean surfaces that force layered crystals into supertwisted spirals. The new work demonstrates a different mechanism altogether, one rooted in the internal architecture of the crystal lattice itself.

The materials at the heart of the study are two-dimensional organic-inorganic hybrid perovskites of the general form (organic)2PbBr4, in which sheets of corner-sharing lead-bromide octahedra are separated by layers of organic cations. These cations are not passive spacers. In the compound (FCA3)2PbBr4, where FCA3 is a fluorinated aromatic cation, the organic layers form hydrogen-bonded networks that the authors describe as hydrogen-bonded organic frameworks embedded within the inorganic lattice. Using single-crystal X-ray diffraction, the team determined the structures at 150 K and 294 K, with crystallographic data deposited at the Cambridge Crystallographic Data Centre under deposition numbers 2485415, 2485416 and 2485417. The structures revealed that the hydrogen-bonded organic networks and the inorganic lead-bromide sheets want to deform in incompatible ways when the crystal grows.

That incompatibility is the essence of geometric frustration. As a ribbon grows from a supersaturated solution, mismatched strains accumulate between the organic and inorganic sublattices. When the strain is released, the ribbon relieves it by bending and twisting, exactly as a seed pod, made of two layers with different shrinkage directions, coils as it dries. The researchers combined brightfield and cross-polarized optical microscopy, scanning electron microscopy, transmission electron microscopy with selected-area electron diffraction, and molecular dynamics simulations to connect the atomic-scale mismatch to the macroscopic shape. The simulations, carried out by Zhichen Nian under the supervision of Brett M. Savoie, reproduced the spontaneous deformation of the ribbons and confirmed that incompatible elasticity within the lattice, rather than any external influence, drives the twisting.

The scale of the phenomenon is remarkable. The team documented ribbons roughly one micrometer wide and about a millimeter long carrying as many as 86 complete twists along their length, grown simply by cooling a supersaturated solution at 2.5 degrees Celsius per minute from 75 to 55 degrees Celsius. Crucially, microscopy under brightfield, photoluminescence and cross-polarized modes showed that the twisted microribbons are free of internal boundaries, meaning each ribbon is a single crystal that has deformed elastically rather than a composite of misoriented domains. Statistical and mechanical analyses of hundreds of ribbons showed that the shape is governed by intrinsic elastic strain and geometric constraints, and that tuning those parameters allows a continuous transition from twisted ribbons to fully helical ones.

Perhaps the most consequential discovery concerns handedness. Because the underlying molecules are achiral, one might expect equal numbers of left- and right-handed ribbons, yielding no net optical signature. Instead, the researchers found that the direction of twisting is controlled by crystal symmetry and by growth kinetics. By adjusting the cooling rate, for example to a slow 0.044 degrees Celsius per minute, they could bias nearly all ribbons in a bulk sample to twist in the same direction, producing centimeter-sized forests of ribbons with a single handedness. Ensemble-averaged circular dichroism measurements on these chirality-pure samples showed genuine chiroptical activity. The team took particular care to isolate the true signal: by rotating the sample about the light axis and flipping it, they removed artifacts arising from linear birefringence and linear dichroism, leaving the circular dichroism that arises from the coupling between electronic and magnetic transition dipoles.

The symmetry analysis explains why the effect appears in some compositions and not others. The inorganic [PbBr4]2- lattices contain specific symmetry elements, such as 21 screw axes or inversion centers, positioned at precise crystallographic sites, and the morphology of the growing crystal reflects these elements. When the team doped a second cation, BrCA3, into the (FCA3)2PbBr4 lattice, the doped crystals adopted the triclinic space group P-1 and their hydrogen-bonded organic networks aligned in a configuration resembling that of the pure (BrCA3)2PbBr4 compound. Partial occupancy refinement, made possible by the strong scattering contrast between fluorine and bromine, established a doping level of about 18 percent in one crystal, corresponding to the composition (FCA3)1.821(BrCA3)0.179PbBr4. The doped crystals showed markedly different twisting behavior, demonstrating that molecular doping offers a practical handle for tuning the frustration and hence the final morphology.

The work situates layered perovskites within a broader family of twisting crystals that includes benzamide, hippuric acid, aspirin and cholesterol monohydrate, all of which form helicoidal or twisted habits through growth-actuated bending. It also echoes recent advances in van der Waals materials, where chiral twisted nanowires and helical crystals with discretized Eshelby twist have been reported, and in nanoplatelet systems where ligand-induced curvature mismatches control polymorphism and chirality. What distinguishes the new result is the mechanism: rather than dislocations, external templates or curved substrates, the twist emerges from the interplay of two chemically distinct, hydrogen-bonded and ionic sublattices within a single crystal. The authors suggest this provides a general strategy for programming chiral shapes into layered two-dimensional materials through molecular design.

The practical implications could extend well beyond crystallography. Chiral perovskites are already of intense interest for spintronics, where chiral-induced spin selectivity has enabled room-temperature spin light-emitting diodes, and for photovoltaics, where chiral-structured heterointerfaces have been shown to improve the durability of solar cells. A material that can be grown in bulk with controlled handedness, using nothing more than cooling rate and molecular doping, would be an attractive platform for such technologies, as well as for circularly polarized light detection and chiral optoelectronics. Because the twisting is an elastic response baked into the lattice, it also raises the possibility of dynamic behavior, analogous to the reversible twisting motions observed in other molecular crystals and to light-powered flagella-like motion in photomechanical microwires.

For now, the study stands as an elegant demonstration that macroscopic chirality can be encoded in the geometry of interactions at the molecular scale. A crystal built from mirror-symmetric parts, given the right internal mismatch and the right growth conditions, will coil itself into a helix with a preferred hand, and that hand can be read out optically from an ensemble of thousands of ribbons. The researchers, whose work was supported by the US Department of Energy Office of Basic Energy Sciences and the US National Science Foundation, describe their results as a route to controlling chiral morphologies in layered two-dimensional materials. If the principle generalizes across the rich family of hybrid perovskites and related layered compounds, the humble twisted ribbon may become a standard building block in the designer materials of the coming decade.

Subject of Research: Geometric frustration driving spontaneous chiral twisting in layered halide perovskite nanoribbons

Article Title: Geometric frustration in morphologically chiral nanoribbons of layered perovskites

Article References: Shao, W., Nian, Z., Lu, Y., Yang, H., Yu, Y., Savoie, B. M., & Dou, L. (2026). Geometric frustration in morphologically chiral nanoribbons of layered perovskites. Nature Synthesis. https://doi.org/10.1038/s44160-026-01167-5

Image Credits: AI Generated

DOI: 10.1038/s44160-026-01167-5

Keywords: layered perovskites, geometric frustration, chirality, nanoribbons, two-dimensional materials, hydrogen-bonded organic frameworks, circular dichroism, molecular doping, crystal growth, elastic strain, chiroptical activity, metal-halide perovskites

Helicenes are ortho-fused polycyclic aromatic compounds that adopt a non-planar, screw-shaped geometry. Because the two possible screw senses, designated P for right-handed and M for left-handed, are mirror images of one another, individual helicenes are inherently chiral even though they contain no classical stereogenic center. When several helicene units are woven into a single nanographene scaffold, the relative arrangement of their screw senses matters enormously. An arrangement in which all helices turn the same way produces a molecule with strong chiroptical activity, while a mixed arrangement can partially or fully cancel the chiral response. Until now, preparing these multi-helical architectures with complete stereochemical control has been a formidable synthetic challenge, because forming each helical rim typically generates a mixture of stereoisomers that are difficult to separate.

The new strategy addresses this problem through a modular design in which stereodefined building blocks are assembled stepwise around a central carbon-rich core. By carefully orchestrating the sequence of cyclization reactions, the chemists can dictate whether each helicene adopts the P or M configuration as it forms, rather than relying on statistical mixtures. This converts what was previously an uncontrolled combinatorial problem into a rational synthesis. The approach proved general enough to furnish hexabenzocoronene derivatives, a class of compact disk-like nanographenes, as well as extended graphene nanoribbon segments decorated with up to eight helicene units all twisting in the same direction.

The significance of achieving uniform helix alignment extends well beyond synthetic elegance. Chiral nanographenes interact differently with left- and right-circularly polarized light, producing large circular dichroism signals and, in some cases, circularly polarized luminescence. Materials that emit or absorb circularly polarized light efficiently are of intense interest for next-generation display technologies, optical data storage, spin-selective electronics, and chiral photonics. The intensity of these effects generally scales with the degree of chiral order in the molecule, so a nanographene bearing eight cooperatively aligned helices can display chiroptical responses far stronger than those of a molecule containing a single helicene.

A particularly striking feature of the reported materials is their near-infrared emissive behavior. Near-infrared emission, roughly in the 700 to 1700 nanometer window, is valuable for biological imaging, telecommunications, and optical sensing, yet most organic molecules emit at shorter wavelengths. Rigid, planarized nanocarbon frameworks tend to reduce the energy gap between their ground and excited states, pushing emission toward longer wavelengths, and the appended helicenes in this work appear to contribute both to the red shift and to the chiral character of the emitted light. Because the synthetic strategy is modular, the researchers can adjust the number, position, and handedness of the helicene units and thereby tune the photophysical and chiroptical properties in a predictable manner rather than by trial and error.

The synthetic logic rests on established carbon-carbon bond-forming reactions, notably oxidative cyclodehydrogenation, which fuses adjacent aromatic rings into the extended graphene-like lattice, combined with diastereoselective steps that lock in the helix handedness. In a diastereoselective transformation, the existing stereochemical information within an intermediate biases the formation of a new stereogenic element toward one outcome. In these nanographenes, the first helix to form sets the conformational stage for its neighbors, and subsequent cyclizations follow the templating influence of the pre-existing helical rims. Enantioselective steps, in contrast, distinguish between the two mirror-image pathways from the outset, allowing the chemists to choose globally left-handed or globally right-handed products. Combining both forms of stereocontrol in one sequence is what makes the construction of up to eight aligned helices feasible.

Multi-helical nanographenes of this kind can be described in terms of their diastereomeric relationships: molecules with the same set of helix configurations but different relative arrangements are diastereomers, while a fully right-handed molecule and its fully left-handed counterpart are enantiomers. Distinguishing and characterizing these species requires sophisticated analytical tools. The researchers relied on standard structural confirmation methods common to the field, including nuclear magnetic resonance spectroscopy to probe the aromatic framework, mass spectrometry to confirm molecular formulas, high-performance liquid chromatography on chiral stationary phases to separate and quantify enantiomers, and circular dichroism spectroscopy to measure the chiroptical signatures. Photoluminescence measurements then quantified how efficiently the materials emit light and at which wavelengths.

The broader context of this work is the growing field of chiral nanocarbons, which includes helically twisted graphene nanoribbons, chiral carbon nanotube models, and saddle-shaped or bowl-shaped polycyclic aromatics. These structures bridge molecular chemistry and materials science: they are discrete, well-defined molecules that can be purified and characterized like ordinary compounds, yet their extended pi-conjugated frameworks give rise to the electronic behavior of graphene, one of the most celebrated materials of the past two decades. Introducing controlled chirality into such frameworks adds a functional dimension that achiral nanographenes lack, enabling interactions with polarized light and with chiral biological or chemical environments.

One of the enduring obstacles in this area has been scalability and stereochemical purity. Many beautiful chiral nanocarbon structures have been reported only as racemic mixtures, in which left- and right-handed forms coexist, limiting their usefulness in devices that exploit circularly polarized light. Others required laborious chiral chromatographic resolution that yields only tiny quantities of material. A stereoselective synthesis that directly delivers a single enantiomer or a defined diastereomer, in modular fashion, represents a meaningful step toward practical exploitation. It also allows systematic structure-property studies, since a family of closely related stereoisomers can be compared to isolate the influence of each helical unit on absorption, emission, and chiroptical response.

Looking forward, the modular nature of the strategy suggests extensions in several directions. Varying the substituents on the helicene rims could modulate solubility, packing in the solid state, and supramolecular assembly, all of which are critical for processing these large molecules into thin films for devices. Incorporating heteroatoms such as nitrogen, boron, or oxygen into the nanographene core could further tailor the electronic structure, potentially yielding ambipolar or n-type chiral semiconductors. Longer graphene nanoribbons with patterned helicene arrays might display anisotropic charge transport combined with strong circular dichroism, a combination relevant to chiral spintronics. And because the emission can reach the near-infrared, biomedical applications that demand deep tissue penetration and chiral light-matter interactions become plausible, provided the materials can be made biocompatible. For now, the immediate achievement is conceptual: demonstrating that multiple helical elements in a single nanographene can be installed with deliberate, uniform stereochemistry, converting a class of molecules once accessible only as complicated mixtures into rationally designed, property-tunable materials for advanced optoelectronics.

Subject of Research: Enantio- and diastereoselective synthesis of multi-helical nanographenes

Article Title: Enantio- and diastereoselective synthesis of multi-helical nanographenes

Article References: Shimizu, R., Nogami, J., Kishida, Y., Morita, F., Maeda, C., Uekusa, H., & Tanaka, K. (2026). Enantio- and diastereoselective synthesis of multi-helical nanographenes. Nature Synthesis. https://doi.org/10.1038/s44160-026-01155-9

Image Credits: AI Generated

DOI: 10.1038/s44160-026-01155-9

Keywords: nanographenes, helicenes, stereoselective synthesis, hexabenzocoronenes, graphene nanoribbons, chirality, chiroptical properties, circularly polarized luminescence, near-infrared emission, polycyclic aromatic hydrocarbons, optoelectronic materials, molecular synthesis