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Category: chemistry

Titanium complexes cleanly edit the core skeleton of highly stable organic compounds

Multi-titanium hydrides can selectively snip the strong structural bonds of stable organic molecules called pyridines, RIKEN researchers have shown. This discovery could guide designing catalysts for applications in multiple branches of industrial chemistry, from oil refining to the synthesis of functional organic molecules. The findings are published in the Journal of the American Chemical Society.

Pyridines are stable aromatic molecules characterized by a ring consisting of one nitrogen atom and five carbon atoms. They are a common structural motif in complex organic molecules such as pharmaceuticals. They are also a component of crude oil that needs to be removed during refining.

“The removal of nitrogen-containing impurities such as pyridines from crude oil is an important industrial process in petroleum refining,” notes Zhaomin Hou of the RIKEN Organometallic Chemistry Laboratory and the RIKEN Advanced Catalysis Research Group.

Twisted bilayer photonic crystals dynamically tune light’s handedness

Researchers at the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) have created a chip-scale device that can dynamically control the “handedness” of light as it passes through—also known as its optical chirality—with a simple twist of two specially designed photonic crystals. The study is published in the journal Optica.

The work, led by graduate student Fan Du in the lab of Eric Mazur, the Balkanski Professor of Physics and Applied Physics, describes a reconfigurable twisted bilayer photonic crystal that can be tuned in real time using an integrated micro-electromechanical system (MEMS). The breakthrough opens new possibilities for advanced chiral sensing, optical communication, and quantum photonics.

“Chirality is very important in many fields of science—from pharma to chemistry, biology, and of course, physics and photonics,” Mazur said. “By integrating twisted photonic crystals with MEMS, we have a platform that is not only powerful from a physics standpoint, but also compatible with the way modern photonics are manufactured.”

Researchers mix X-rays and optical light to track speedy electrons in materials

To unlock materials of the future, including better photocatalysts or light-switchable superconductors, researchers need to understand how the valence electrons within materials respond to light at the atomic scale. Materials are made of atoms, and an atom’s outer electrons, or valence electrons, are responsible for chemical bonding as well as a material’s thermal, magnetic, and electronic properties.

But imaging valence electrons in bulk materials is extremely difficult because valence electrons are only a small subset of a typically large pool of electrons.

Now, researchers at the Department of Energy’s SLAC National Accelerator Laboratory have refined a way to track valence electrons using a unique method that shines both X-rays and lasers onto a material, then tracks the frequency generated by both sources. The method allows the researchers to understand more about extremely fast-moving valence electrons, including the symmetry of their local environment.

Tubulin prevents toxic protein clump formation

“This led us to the following idea: what if instead of preventing the formation of droplets, we created conditions that would drive Tau and alpha synuclein inside the droplets toward their healthy path, discouraging them from taking the disease path?” said a co-corresponding author of the work.

The team worked with biochemical and biophysical techniques, high-resolution microscopy and neuronal-based assays to investigate tubulin’s role in modulating and preventing the formation of toxic aggregates in droplets.

The researchers show that Tubulin modulates Tau:αSyn condensates by promoting microtubule interactions and inhibiting homotypic and heterotypic pathological oligomers. Tubulin partitioning into condensates promotes microtubule polymerization and prevents Tau and αSyn oligomerization.

In the absence of Tubulin, Tau-driven condensation accelerates formation of pathogenic Tau:αSyn heterodimers and amyloid fibrils. The authors also identify distinct Tau and αSyn structural states in pathological Tubulin-absent versus physiological Tubulin-rich condensates.

“When tubulin levels are low, as it has been found in Alzheimer’s disease, microtubules are less abundant and Tau and alpha synuclein can form toxic aggregates,” the author said. “But when tubulin is present, Tau and alpha‑synuclein shift away from harmful aggregates and instead promote the assembly of healthy microtubules,” the author said. “Tubulin redirects the activity of these proteins by giving them something productive to do.” ScienceMission sciencenewshighlights.

Researchers have discovered a potential new strategy to fight back against Alzheimer’s and Parkinson’s diseases, conditions that are linked to the toxic accumulation of Tau and alpha synuclein protein clumps in the brain. The team reports in Nature Communications that tubulin, the building block of microtubules, the cell’s internal ‘railway tracks,’ can stop Tau and alpha synuclein from forming toxic clumps and instead steer them into their normal, healthy roles.

Continue reading “Tubulin prevents toxic protein clump formation” | >

Quantum materials could enable the solar-powered production of hydrogen from water

Hydrogen fuel is a promising alternative to fossil fuels that only emits water vapor when used and could thus help to lower greenhouse gas emissions on Earth. In the future, it could potentially be used to fuel heavy-duty transport vehicles, such as trucks, trains, and ships, as well as industrial heating and decentralized power generation systems.

Unfortunately, most current methods to produce hydrogen rely on the burning of fossil fuels, which limits its environmental advantages. Given its potential, many energy engineers worldwide have been trying to devise more sustainable strategies to produce hydrogen on a large scale.

One proposed method for the clean production of hydrogen is known as photocatalytic water splitting. This approach entails splitting water molecules into hydrogen and oxygen, using photocatalysts (i.e., materials that respond to sunlight and prompt desired chemical reactions).

Hybrid synthetic strategy unlocks previously unattainable molecular architectures

The molecular-scale design of materials is one of the major frontiers in modern science. Flat, highly conjugated organic molecules are already used in advanced technologies such as chemical sensors, optoelectronic devices, and energy conversion systems. One of the most promising strategies to enhance their performance involves “linking” multiple units together, extending their electronic structure and thereby modifying their properties.

However, as these architectures grow in complexity, their synthesis becomes extremely challenging. In many cases, the molecules lose solubility and become nearly inaccessible through traditional solution-based methods. This limitation has hindered the construction of increasingly large and functional molecular structures for years.

Research led by Luis M. Mateo and Diego Peña at the Center for Research in Biological Chemistry and Molecular Materials (CiQUS) has overcome this barrier using a hybrid strategy. First, they synthesize carefully designed phthalocyanine units in solution. These units are then deposited onto a metal surface, where they react with each other to form a new extended structure composed of five cross-shaped, fused phthalocyanines. This approach combines the precision of classical solution chemistry with the possibilities offered by on-surface synthesis under controlled conditions.

Chemical shifts help track molecules breaking apart in real time

When molecules fall apart, their electric charge doesn’t stay put—it rearranges as bonds stretch and break. An international team of scientists has now tracked these ultrafast changes in the small molecule fluoromethane (CH₃F). It was the first time that the Small Quantum Systems (SQS) instrument at European XFEL could deliver detailed insights into transient states during chemical reactions. The research is published in the journal Physical Review X.

These intermediate states, that only exist temporarily while the reaction is ongoing, are often the key drivers of chemistry and therefore crucial to understand. Over the long term, that kind of insight can support progress in areas such as atmospheric science (where sunlight-driven reactions and fragmentation pathways shape air chemistry), as well as the study of complex molecular systems including biomolecules and proteins, where local excitation and charge transfer can trigger structural change.

In the experiment, the researchers first triggered the reaction with an optical laser pulse. Next, they used the X-ray laser pulses that the European XFEL produces, to eject an electron from the core of either the fluorine or the carbon atom in the molecule. They measured the electron’s kinetic energy, which reveals how strongly it was bound inside the atom. That binding energy is extremely sensitive to the local electrical environment, producing so-called “chemical shifts” that act like a fingerprint of the charge distribution surrounding the atom from which the electron has been ejected.

Electron microscopy maps protein landscapes that drive photosynthesis

Research led by scientists at Washington State University has revealed insights on how plants form a microscopic landscape of proteins crucial to photosynthesis, the basis of Earth’s food and energy chain. The discovery provides a new view of the molecular engine that converts sunlight into bioenergy and could enable future fine-tuning of crops for higher yields and other useful traits.

Colleagues at WSU, the University of Texas at Austin, and the Weizmann Institute of Science in Israel used a novel, technology-powered approach to peer inside plant leaf cells and visualize the landscape of the photosynthetic membrane—the ribbon-like structure where plants harvest sunlight. The findings were recently published in the journal Science Advances.

“These membranes are highly efficient biological solar cells,” said the study’s principal investigator and corresponding author, Helmut Kirchhoff. “They convert sunlight energy into chemical energy that fuels not only the plant’s metabolism but that of most life on Earth.”

JWST Detects Evidence of “Monster Stars” That May Have Created the Universe’s First Giant Black Holes

Using the James Webb Space Telescope, an international team of researchers has discovered chemical fingerprints from enormous primordial stars that were among the first to form after the Big Bang.

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