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Category: chemistry – Page 5

Chemists solve century-old mechanistic puzzle of copper catalyst

The Ullmann reaction is one of the oldest reactions in organometallic chemistry. It is one of the most widely used copper-mediated coupling reactions, widely applied in the construction of carbon-carbon and carbon-heteroatom bonds due to its excellent substrate generality.

There has been considerable controversy regarding the redox mechanism of copper in this reaction for a long time. The widely accepted mechanistic hypothesis involves a Cu(I/III) cycle. However, copper(III) species are extremely difficult to observe in real reaction systems, and whether other interactions exist between copper species remains unknown.

In a study published in Nature on September 22, Shen Qilong’s lab from the Shanghai Institute of Organic Chemistry of the Chinese Academy of Sciences, along with Professor K. N. Houk from the University of California, Los Angeles, provided solid evidence that the Ullmann-type reaction might proceed via a Cu(I)/Cu(III)/Cu(II)/Cu(III)/Cu(I) catalytic cycle.

Energy-efficient catalyst converts water pollutants into useful ammonia

When the current method for producing something is estimated to consume a staggering 1–2% of the annual global energy supply, it means we need to make a change. The Haber-Bosch process produces ample amounts of ammonia (NH3)—a valuable chemical compound that has a wide array of uses in fields such as agriculture, technology, and pharmaceuticals—while consuming a lot of energy.

A research team at Tohoku University has made a significant contribution to an alternate method for converting harmful nitrate pollutants in water into ammonia, addressing both environmental and energy challenges.

Their findings are published in Advanced Functional Materials.

Physicists set record with 6,100-qubit array

Quantum computers will need large numbers of qubits to tackle challenging problems in physics, chemistry, and beyond. Unlike classical bits, qubits can exist in two states at once—a phenomenon called superposition. This quirk of quantum physics gives quantum computers the potential to perform certain complex calculations better than their classical counterparts, but it also means the qubits are fragile. To compensate, researchers are building quantum computers with extra, redundant qubits to correct any errors. That is why robust quantum computers will require hundreds of thousands of qubits.

Now, in a step toward this vision, Caltech physicists have created the largest array ever assembled: 6,100 neutral-atom qubits trapped in a grid by lasers. Previous arrays of this kind contained only hundreds of qubits.

This milestone comes amid a rapidly growing race to scale up quantum computers. There are several approaches in development, including those based on superconducting circuits, trapped ions, and neutral atoms, as used in the new study.

Broadband photodetector material senses visible light to long-wave infrared, simplifying device design

A research team in South Korea has developed a next-generation sensor material capable of integrating the detection of multiple light wavelengths.

A joint research team led by Dr. Wooseok Song at the Korea Research Institute of Chemical Technology (KRICT) and Professor Dae Ho Yoon at Sungkyunkwan University successfully developed a new photodetector material that can sense a wider range of wavelengths compared to existing commercial materials, and achieved cost-effective synthesis on a 6-inch wafer-scale substrate.

This research is published in ACS Nano.

Key enzyme for high-value natural sweetener production identified and characterized

Steviol glycosides, natural sweeteners extracted from Stevia rebaudiana, are widely used as sucrose substitutes due to their high sweetness and low caloric value. Among them, Rebaudioside M (Reb M) is regarded as a next-generation, high-value steviol glycoside product because of its intense sweetness and superior taste profile. However, the natural abundance of Reb M in Stevia is extremely low.

Efficient biosynthetic methods are needed to meet market demand. Until now, the key enzyme catalyzing the conversion of Rebaudioside D (Reb D) to Reb M in the has not been identified, and it is generally assumed to be UGT76G1. However, UGT76G1 exhibits strict regioselectivity for the C13 position of steviol glycosides, while its at the C19 position is very weak.

In a study published in the Proceedings of the National Academy of Sciences on September 17, a team led by Prof. Yin Heng from the Dalian Institute of Chemical Physics of the Chinese Academy of Sciences identified the key glycosyltransferase that catalyzes the conversion of Reb D to Reb M, and revealed the underlying its substrate regioselectivity.

Johns Hopkins Unlocks New Chemistry for Faster, Smaller Microchips

“By playing with the two components (metal and imidazole), you can change the efficiency of absorbing the light and the chemistry of the following reactions. And that opens us up to creating new metal-organic pairings,” Tsapatsis said. “The exciting thing is there are at least 10 different metals that can be used for this chemistry, and hundreds of organics.”

Looking Ahead to Next-Gen Manufacturing

The researchers have started experimenting with different combinations to create pairings specifically for B-EUV radiation, which they say will likely be used in manufacturing in the next 10 years.

Mars Perseverance rover data suggests presence of past microbial life

A new study co-authored by Texas A&M University geologist Dr. Michael Tice has revealed potential chemical signatures of ancient Martian microbial life in rocks examined by NASA’s Perseverance rover.

The findings, published by a large international team of scientists, focus on a region of Jezero Crater known as the Bright Angel formation—a name chosen from locations in Grand Canyon National Park because of the light-colored Martian rocks. This area in Mars’s Neretva Vallis channel contains fine-grained mudstones rich in oxidized iron (rust), phosphorus, sulfur and—most notably—organic carbon. Although organic carbon, potentially from non-living sources like meteorites, has been found on Mars before, this combination of materials could have been a rich source of energy for early microorganisms.

“When the rover entered Bright Angel and started measuring the compositions of the local rocks, the team was immediately struck by how different they were from what we had seen before,” said Tice, a geobiologist and astrobiologist in the Department of Geology and Geophysics.

Novel gene therapy for hereditary hearing loss developed at Tel Aviv University

Scientists from the Gray Faculty of Medical & Health Sciences at Tel Aviv University introduced an innovative gene therapy method to treat impairments in hearing and balance caused by inner ear dysfunction. According to the researchers, “This treatment constitutes an improvement over existing strategies, demonstrating enhanced efficiency and holds promise for treating a wide range of mutations that cause hearing loss.”

The study was led by Prof. Karen Avraham, Dean of the Gray Faculty of Medical & Health Sciences, and Roni Hahn, a PhD student from the Department of Human Molecular Genetics and Biochemistry. The study was conducted in collaboration with Prof. Jeffrey Holt and Dr. Gwenaëlle Géléoc from Boston Children’s Hospital and Harvard Medical School and was supported by the US-Israel Binational Science Foundation (BSF), the National Institutes of Health/NIDCD and the Israel Science Foundation Breakthrough Research Program. The study was featured on the cover of the journal EMBO Molecular Medicine.

Prof. Avraham explains: “The inner ear consists of two highly coordinated systems: the auditory system, which detects, processes, and transmits sound signals to the brain, and the vestibular system, which enables spatial orientation and balance. A wide range of genetic variants in DNA can affect the function of these systems, leading to sensorineural hearing loss and balance problems. Indeed, hearing loss is the most common sensory impairment worldwide, with over half of congenital cases caused by genetic factors. In this study, we aimed to investigate an effective gene therapy for these cases using an approach that has not been applied in this context before.”

Researchers develop the first room temperature all-solid-state hydride ion battery

Hydride ion (H-), with their low mass and high redox potential, are considered promising charge carriers for next-generation electrochemical devices. However, the lack of an efficient electrolyte with fast hydride ion conductivity, thermal stability, and electrode compatibility has hindered their practical applications.

In a study published in Nature, Prof. Chen Ping’s group from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences (CAS) developed a novel core–shell ion electrolyte, and constructed the first room temperature all-solid-state rechargeable hydride ion battery.

Using a heterojunction-inspired design, researchers synthesized a novel core–shell composite hydride, 3CeH3@BaH2, where a thin BaH2 shell encapsulates CeH3. This structure leverages the high hydride ion conductivity of CeH3 and the stability of BaH2, enabling fast hydride ion conduction at room temperature along with high thermal and electrochemical stability.

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