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Hydrogen atom transfer method selectively transforms carboxylic acids using an inexpensive photocatalyst

Carboxylic acids are ubiquitous in bioactive organic molecules and readily available chemical building blocks. Carboxylic acids can be converted into carboxy radicals that can initiate versatile carbon–carbon and carbon–heteroatom bond formations, which are highly desirable for developing materials and pharmaceuticals. Currently, however, there are few applicable methods that use inexpensive catalysts.

To this end, researchers from WPI-ICReDD and University of Shizuoka have developed a facile hydrogen atom transfer (HAT) method that selectively transforms into carboxy radicals using xanthone, an inexpensive commercial organic ketone photocatalyst. This research was published in the Journal of the American Chemical Society.

HAT converts substrates into radical species by removing a hydrogen atom and ketones are highly accessible, inexpensive, and known for HAT photocatalysis. However, selective HAT for carboxylic acids is challenging because the O–H bond is stronger than adjacent C–H bonds. Nonetheless, using the artificial force–induced reaction (AFIR) method, a developed at ICReDD, the authors identified xanthone as a promising ketone photocatalyst for selective O–H bond HAT.

Physicists reveal how a lone spinon emerges in quantum magnetic models

Researchers from the Faculty of Physics at the University of Warsaw and the University of British Columbia have described how a so-called lone spinon—an exotic quantum excitation that is a single unpaired spin—can arise in magnetic models. The discovery deepens our understanding of the nature of magnetism and could have implications for the development of future technologies such as quantum computers and new magnetic materials. The work is published in Physical Review Letters.

Magnetism has been known to humanity since ancient times, when naturally magnetized magnetite was discovered. This finding soon found highly practical applications. The first compasses were created in the in China, and began to be used for navigation.

Today, magnets play an important role in many technologies that surround us, from computer memory and speakers to and medical diagnostics. Interestingly, alongside photography, magnets have also become a common souvenir of travel, occupying a prominent place in our homes.

Detecting Ice Structures from Space

Depending on the temperature and pressure, ice adopts one of 20 different crystalline phases. Researchers can typically tell one ice phase from the other using x rays or neutron beams, but such techniques are impractical for studying ice on distant celestial bodies. Thomas Loerting from the University of Innsbruck in Austria and his colleagues have now shown that infrared spectroscopy can discriminate between two types of high-pressure ice [1]. The results suggest that astronomical observatories in the infrared could probe ice-covered planets or moons, revealing information about their geological evolution and potential habitability.

The ice in your freezer is hexagonal ice, but at lower temperatures, higher pressures, or both, other forms can exist. Ice phases are distinguished by the ordering of oxygen atoms and hydrogen atoms. For example, ice V has oxygens arranged in ring structures, while its hydrogens have random (disordered) positions. This phase, which is stable at pressures of 500 megapascals and temperatures of 253 K, is thought to form in the interior of Jupiter’s moon Ganymede, Saturn’s moon Enceladus, and other icy moons.

In the lab, Loerting’s colleague, Christina Tonauer, created ice V, along with a related, hydrogen-ordered version called ice XIII. The team performed near-infrared spectroscopy on both samples and identified several distinguishing features, including a structure-dependent “shoulder” around 1.6 µm, a wavelength associated with stretching modes. According to the team’s calculations, the features are strong enough that astronomical instruments, such as those on the JWST observatory and the Jupiter-visiting JUICE mission, could potentially observe them on a body like Ganymede. “The detection of high-pressure ice phases at or near the surface could point to internal processes such as tectonic activity, cryovolcanism, or convective transport from deeper layers,” Loerting says.

Rethinking the Anomalous Hall Effect: A Symmetry Revolution

A new symmetry-breaking scenario provides a comprehensive description of magnetic behavior associated with the anomalous Hall effect.

In 1879 Edwin Hall discovered that a flat conductor carrying current, when placed in a magnetic field, will develop a transverse voltage caused by the deflection of charge carriers. Two years later he discovered that the same effect arises in ferromagnets even without an applied magnetic field. Dubbed the anomalous Hall effect (AHE), that phenomenon, alongside the ordinary Hall effect, not only catalyzed the rise of semiconductor physics and solid-state electronics but also laid the groundwork for a revolutionary convergence of topology and condensed-matter physics a century after Hall’s discoveries. Recent experiments, however, have uncovered behavior that cannot be explained with current theories for the AHE.

Cracking the quantum code: Light and glass are set to transform computing

European researchers are developing quantum computers using light and glass, in a collaboration that promises breakthroughs in computing power, battery technology and scientific discovery.

Giulia Acconcia grew up in the picturesque, historic town of Spoleto, nestled in the foothills of Italy’s Apennine Mountains. Already in secondary school, she became fascinated with modern technology—a passion that would shape her future.

Her love of electronics led her to the Polytechnic University of Milan, Italy, where she now finds herself at the forefront of quantum computing research.

Individual defects in superconducting quantum circuits imaged for the first time

Individual defects in superconducting quantum circuits have been imaged for the first time, thanks to research by scientists at the National Physical Laboratory (NPL) in collaboration with Chalmers University of Technology and Royal Holloway University of London.

Light and heavy electrons cooperate in magic-angle superconductors

Electrons play many roles in solid materials. When they are weakly bound and able to travel—i.e., mobile—they can enable electrical conduction. When they are bound, or “heavy,” they can act as insulators. However, in certain solid materials, this behavior can be markedly different, raising questions about how these different types of electrons interact.

In a study just published in Nature Physics, researchers working with Professor of Physics and Applied Physics Amir Yacoby at Harvard examined the interplay between both types of electrons in this material, shedding new on how they may help form novel quantum states.

“Before our work, people could only ask ‘What is the overall ground state?’” said Andrew T. Pierce, one of the paper’s lead authors. Pierce, currently a fellow at Cornell University, was a graduate student in Yacoby’s lab when they began to study this question. What wasn’t clear was the true nature of these different states and how the separate light and heavy electrons joined forces to form them.

Quantum enhancement discovery could improve medical technologies

Technologies such as biomedical imaging and spectroscopy could be enhanced by a discovery in research that involved several institutions, including the University of Glasgow. Scientists have found that two-photon processes, which have applications in the study of Alzheimer’s disease and other nervous system disorders, can be strengthened by quantum light at far higher levels than previously thought possible.

The processes normally require high-intensity light but this can cause samples to be damaged or bleached.

It was suggested many years ago—and has since been demonstrated—that entangled could overcome this limitation. However, it has been widely believed that this quantum enhancement only survives for very faint light, raising doubts about the usefulness of the approach.