Plate Nº 80 · recorded November 13, 2026
PhysicsReported finding
Porous Crystals Lay Groundwork for Quantum Chemical Sensing
An international team created polarized radical pairs in porous metal–organic frameworks and showed that their electron spins respond to some chemicals, a step toward quantum sensors.
By Elena Vasquez3 min read680 words
In brief
- 2026: The results appeared in Nature Communications.
- An international team led by Nobuhiro Yanai and Michael R. Wasielewski built an ordered array of polarized radical pairs in a metal–organic framework.
- Three analytical methods evaluated molecular variations: ultrafast spectroscopy, electron paramagnetic resonance spectroscopy and quantum chemical theory calculations.
- The team demonstrated that spin properties responded to some chemical substances.
- Next step: explore more spin systems in MOFs and test their responses to chemical stimuli.
By Elena Vasquez
A 2026 study reports that an international team created polarized radical pairs inside porous crystals, a possible foundation for more sensitive chemical sensors.
Polarized radical pairs contain unpaired electrons whose spins align. The researchers placed these pairs inside metal–organic frameworks, or MOFs, which are highly porous materials made of metal ions linked by organic molecules.
The team published the work in Nature Communications. The controlled spin alignment could support future quantum chemical sensing and might eventually improve the sensitivity of existing techniques such as magnetic resonance imaging, or MRI.
For now, the MRI benefit is prospective. The reported result concerns a material that responds to selected chemicals, not a demonstrated MRI enhancement or a finished chemical-sensing device.
What did the team achieve?
Researchers at the University of Tokyo and Northwestern University, led by Nobuhiro Yanai and Michael R. Wasielewski, carried out the international effort. Their goal was to arrange radical pairs in a predictable, repeated structure inside a solid.
Yanai, the principal investigator, said: “We are interested in making a quantum nose, so to speak. Although quantum sensing has been a very hot topic in the past decades, leveraging it for chemical sensing has been lagging. Our goal is to make chemical quantum sensing a reality.”
Wasielewski said: “Thus far, research into radical pairs has been limited to isolated molecules in the solid state. So, we set out to develop a method to make an ordered array of radical pairs in a crystalline solid.”
That ordered array was the technical target. It was the key step.
Takeaway: The team built a material whose electron spins respond to selected chemicals, but not yet a finished detector.
How could the material become a quantum sensor?
Sensing starts with detecting a change caused by a specific trigger. The team used smell as an illustration: nerve cells tuned to certain chemicals activate when those chemicals enter the air, then send signals the brain interprets as fruity or floral.
The researchers’ broader premise is that scientific understanding both demands and enables greater sensitivity, resolution and variety in sensing, potentially down to the quantum level. A quantum sensor would exploit quantum properties to register chemical changes.
MOFs are useful because their many pores make them containers. Radical pairs offer the quantum properties needed for a possible sensor. The researchers combined two ingredients that were already fairly well understood but had not yet been assembled in the required ordered array.
Takeaway: In principle, the proposed sensor would use changes in electron spin to detect chemicals.
How did they build and test the radical pairs?
The researchers first designed and synthesized molecules that could transfer electrons after light excited them. They then made variations of those molecules and evaluated each one with three kinds of analysis:
- Ultrafast spectroscopy follows changes over very short timescales.
- Electron paramagnetic resonance spectroscopy measures the behavior of electron spins.
- Quantum chemical theory calculations model how the molecular system should behave.
Using several teams across borders made it possible to carry out the complex project.
Yanai credited the collaboration for creating a pair of radicals and demonstrating how their spin properties responded to some chemical substances.
More spin systems are next. The researchers hope to explore a variety of spin systems in MOFs and their responses to chemical stimuli.
Takeaway: Light activated the molecules, and their aligned spins responded to selected chemicals.
What remains before a practical sensor?
The result remains a material-and-response demonstration. The team showed a spin response to some chemicals, while a finished detector and any MRI improvement remain future steps.
Broader chemical testing comes next. The researchers hope to explore a variety of spin systems in MOFs and their responses to chemical stimuli.
The final paper, “Sublevel-Selective Electron Spin Hyperpolarization of Triplet Radical Pairs in Metal–Organic Frameworks,” appeared in Nature Communications in 2026. Here, “hyperpolarization” refers to enhanced alignment of electron spins.
Its digital object identifier is 10.1038/s41467-026-79262-6.
Takeaway: The material is a starting point; broader chemical sensing and possible MRI gains still require further work.
via phys.org/rss-feed/ (Source)
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Correspondent covering money, funding and market shifts around general science news at SciBeat.
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