Chemistry news and discussions

[wjfox]

Tiny ‘quantum dot’ particles win chemistry Nobel

04 October 2023

Three chemists who predicted and were first to make quantum dots — nanoscale crystals that interact with light in unusual ways — have been awarded the Nobel Prize in Chemistry.

Moungi Bawendi at the Massachusetts Institute of Technology in Cambridge, Louis Brus at Columbia University in New York City and Alexei Ekimov at New York City-based company Nanocrystals Technology will each receive one-third of the 11-million-Swedish-krona (US$1-million) prize.

“It’s an amazing result for the quantum-dot community,” says Mark Green, a physicist at King’s College London. “The theoretical frameworks provided by Brus and Ekimov were made into a reality with Bawendi’s seminal paper in 1993, from which this now-mature science sprung.”

Quantum dots are semiconductor crystals consisting of just a few thousand atoms, which have some properties of single atoms. This allows them to be tuned so they can emit specific wavelengths of light. Very small quantum dots of cadmium selenide, for example, can emit blue light, but bigger crystals of the same compound emit red light. Quantum dots are used in applications that need specific wavelengths of light, from bright television displays to biological imaging.

https://www.nature.com/articles/d41586-023-03048-9

[weatheriscool]

Water can evaporate with just light, no heat, says surprising study
By Michael Irving
October 31, 2023

Contrary to what we all learned in elementary school science class, it turns out that heat may not be necessary to make water evaporate. Scientists at MIT have made the surprising discovery that light alone can evaporate water, and is even more efficient at it than heat. The finding could improve our understanding of natural phenomena or boost desalination systems.

Evaporation occurs when water molecules near the surface of the liquid absorb enough energy to escape into the air above as a gas – water vapor. Generally, heat is the energy source, and in the case of Earth’s water cycle, that heat comes primarily from sunlight.

https://newatlas.com/science/water-evap ... t-no-heat/

[weatheriscool]

Chemists make breakthrough in drug discovery chemistry: Two methods to replace carbon with a nitrogen atom in a molecule
https://phys.org/news/2023-11-chemists- ... istry.html
by Louise Lerner, University of Chicago

For years, if you asked the people working to create new pharmaceutical drugs what they wished for, at the top of their lists would be a way to easily replace a carbon atom with a nitrogen atom in a molecule.

But two studies from chemists at the University of Chicago, published in Science and Nature, offer two new methods to address this wish. The findings could make it easier to develop new drugs.

"This is the grand-challenge problem that I started my lab to try to solve," said Mark Levin, an associate professor of chemistry and the senior author on both papers. "We haven't totally solved it, but we've taken two really big bites out of the problem, and these findings lay a clear foundation for the future."

[weatheriscool]

Deep learning model can detect a previously unknown quasicrystalline phase
https://phys.org/news/2023-11-deep-prev ... phase.html
by Tokyo University of Science

Crystalline materials are made up of atoms, ions, or molecules arranged in an ordered, three-dimensional structure. They are widely used for the development of semiconductors, pharmaceuticals, photovoltaics, and catalysts.

The type of structures that fall into the category of crystalline materials continues to expand as scientists design novel materials to address emerging challenges pertaining to energy storage, carbon capture, and advanced electronics.

[weatheriscool]

New AI model identifies new pharmaceutical ingredients and improves existing ones
https://phys.org/news/2023-11-ai-pharma ... ients.html
by Daniel Meierhans, ETH Zurich

New active pharmaceutical ingredients lay the foundations for innovative and better medical treatments. However, identifying them and, above all, producing them through chemical synthesis in the laboratory is no mean feat. To home in on the optimum production process, chemists normally use a trial-and-error approach: they derive possible methods for laboratory synthesis from known chemical reactions and then test each one with experiments, a time-consuming approach that is littered with dead ends.

Now, scientists at ETH Zurich, together with researchers from Roche Pharma Research and Early Development, have come up with an approach based on artificial intelligence that helps to determine the best synthesis method, including its probability of success. Their paper is published in the journal Nature Chemistry.

[weatheriscool]

Researchers develop biodegradable polymers that are traceable without toxic contrast agents
https://phys.org/news/2023-11-biodegrad ... trast.html
by J. G. M. Van Den Elshout, University of Twente

Polyphosphoesters, molecules containing phosphorus as the central element, are easily traceable without the need for contrast agents, thanks to developments by researchers from the University of Twente (UT). Normally, these molecules display a similar molecular composition to our DNA, leading to considerable "noise" in the image.

The UT researchers provided a solution and developed unique polymers that are traceable with magnetic resonance imaging (MRI). Dr. Olga Koshkina, Project Leader in the Sustainable Polymer Chemistry Group, published this new concept of traceable polymers in Communications Chemistry.

The researchers adjusted the properties of polyphosphoesters (special polymers with a molecular structure inspired by DNA and RNA). As a result, the polymers acquired a different "MRI color," making them more distinguishable from the natural background. Additionally, they exhibit other physical MRI characteristics suitable for imaging.

[weatheriscool]

]Neutron scattering study points the way to electrochemical for carbon-neutral ammonia
https://phys.org/news/2023-12-neutron-e ... monia.html
by Sumner Brown Gibbs, Oak Ridge National Laboratory

Scientists from Stanford University and the Department of Energy's Oak Ridge National Laboratory are turning air into fertilizer without leaving a carbon footprint. Their discovery could deliver a much-needed solution to help meet worldwide carbon-neutral goals by 2050.

Published in the journal Energy & Environmental Science, the study describes a sustainable electrochemical—rather than chemical—process for producing ammonia, a key ingredient for nitrogen fertilizer.

In essence, the researchers used neutron scattering to understand how cycling an electric current during the conversion of nitrogen to ammonia, also known as the nitrogen reduction reaction, increases the amount of ammonia produced. This process has the potential to enable farmers to convert nitrogen, the most abundant element in our atmosphere, into ammonia-based fertilizers without emit

ting carbon dioxide.

[Tadasuke]

I've always considered chemistry (and basically all science, even if I studied it) as awful. I literally hate, hate, hate how all of it works. It doesn't seem appealing or fun in the slightest, no matter how many years pass and the more I know, the more I hate it.

However, my view is, that we unfortunately really need to study all of it, in order to learn how to create virtual realities, where everything works totally differently, how we like, not how we are forced. But first we have to understand, learn and teach, how this awful universe works. Then, we may be able to make a fundamentally different one, and perhaps even erase our memories from this one (at least for some time).

On the one hand I understood pupils at school who didn't want to learn, but at the same time I explained that we need to learn in order to escape this f***ed up reality by building a different one. Of course I was usually laughed at, but whatever. Not everyone fits to a group well. Chemistry is certainly important and essential.

[weatheriscool]

A 3D magnesiophilic substrate enables planar electroplating/stripping of magnesium metal anode

by Zhang Nannan, Chinese Academy of Sciences

As a promising candidate to current lithium-ion batteries, rechargeable magnesium batteries have attracted extensive attention due to the superior properties of magnesium (Mg) metal anodes, such as high volumetric capacity (3,833 mAh/cm3), abundant resources, environmental friendliness, and difficult to grow dendrites.

Although some studies have reported that the morphology of Mg dendrites can be observed under extreme electroplating conditions, such as using the limited Mg electrolytes with low Mg-ion conductivity and applying ultra-high current density (10 mAh/cm2), these test conditions are clearly different from practical requirements.

Researchers from the Qingdao Institute of Bioenergy and Bioprocess Technology of the Chinese Academy of Sciences (CAS) have discovered that the use of the practical polyolefin separator indeed causes the short-circuit of coin cell even at the low current density. They have established a layer-by-layer planar growth model for short-circuit suppression, and proposed the design strategy of a 3D magnesiophilic substrate to achieve planar Mg electroplating/stripping behavior.

The study was published in ACS Energy Letters on Dec. 4.

Ample evidence has shown that Mg growth is uniform and dense when the current density is below 5 mAh/cm2. However, using practical polyolefin separators with the thin thickness, low-current charging and discharging can cause internal short-circuiting in coin cells.

The researchers have proposed the island-growth model for Mg deposits based on electrochemical tests and microscopic morphology observation, which reasonably explains the abnormal short-circuit behavior.

https://phys.org/news/2023-12-3d-magnes ... lanar.html

[weatheriscool]

New catalytic technique creates key component of incontinence drug in less time
https://phys.org/news/2024-01-catalytic ... nence.html
by Nagoya University

A research group at Nagoya University in Japan has developed a new catalyst that promises to revolutionize the asymmetric synthesis of pharmaceuticals called chiral macrocyclic dilithium(I) salt. It overcomes the lack of reactivity of ketones and the difficulty inducing them to arrange atoms, which are common challenges in drug-making.

The researchers used their technique to synthesize a key intermediate of the incontinence drug oxybutynin. Their catalyst promises to contribute to future drug discovery and development. They published their results in the Journal of the American Chemical Society.