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weatheriscool
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Chemistry news and discussions

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Scientists demonstrate a better, more eco-friendly method to produce hydrogen peroxide
https://phys.org/news/2021-06-scientist ... oxide.html
by University of Illinois at Urbana-Champaign
University of Illinois researchers demonstrate a more efficient and environmentally friendly method to produce hydrogen peroxide with palladium-gold nanoparticles, a catalyst that they found performs better when the palladium particles are surrounded by gold. Credit: Claire Benjamin/University of Illinois Urbana-Champaign

Hydrogen peroxide (H2O2) is used to disinfect minor cuts at home and for oxidative reactions in industrial manufacturing. Now, the pandemic has further fueled demand for this chemical and its antiseptic properties. While affordable at the grocery store, H2O2 is actually difficult and expensive to manufacture at scale.

A team led by the University of Illinois Urbana-Champaign has demonstrated a more efficient and environmentally friendly method to produce H2O2, according to a recent study published in the Journal of the American Chemical Society.
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caltrek
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My Ph.D. Supervisor Just Won the Nobel Prize in Chemistry for Designing a Safer, Cheaper and Faster Way to Build Molecules and Make Medicine
David Nagib
October 6, 2021

https://theconversation.com/my-ph-d-sup ... ine-169427

Introduction:
(The Conversation) The reason that ibuprofen treats headaches and ice cream tastes sweet is that their chemical components fit perfectly into certain receptors in your body. The better a drug or flavor molecule fits with its matching receptor, the more effective the medicine or tastier the treat.

But an interesting quirk of nature is that many molecules can come in two versions – a right–handed version and left–handed version – and receptors in your body must match the handedness of a molecule to fit correctly. A left–handed glove won’t fit on your right hand.

So how do chemists make the correct version of a molecule so that drugs work as intended?

This is a question I as a chemist was deeply fascinated by when I started my Ph.D. studies with Dave MacMillan at Princeton. And he, along with Ben List of the Max Planck Institute, have together won the 2021 Nobel Prize in Chemistry for discovering entirely new ways to make molecules of one orientation or another.

They developed a new simple type of catalyst – called asymmetric organocatalysts. These catalysts are able to efficiently produce molecules with a particular 3-D orientation and have enabled chemists to discover and manufacture safe and effective drugs.

Image
All molecules can come in right–handed or left–handed versions that are mirror opposites of each other but not identical.
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weatheriscool
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Weak bonds are a strength in making borophene
https://phys.org/news/2021-11-weak-bond ... phene.html
by Rice University

Borophene may be done tantalizing materials scientists and start serving their ambitions, if a new approach by Rice University researchers can be turned into practice.

Materials theorist Boris Yakobson of Rice's George R. Brown School of Engineering and his group suggest a method to synthesize borophene, the 2D version of boron, in a way that could make it easier to free up or manipulate.

According to the group's paper in the American Chemical Society journal ACS Nano, that would involve growing the exotic material on hexagonal boron nitride (hBN), an insulator, rather than the more traditional metallic surfaces typically used in molecular beam epitaxy (MBE).

The weaker van der Waals forces between the growing borophene and relatively chemically inert hBN would make it easier to remove the material from the substrate to use in applications. It would also allow for simpler direct evaluation of borophene (without lifting it from the substrate) for its plasmonic and photonic—that is, light-handling—properties because there would be no metallic substrate to interfere. That would also aid experimentation on its electronic properties, which could be of interest to those who study superconductivity.
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A way to conduct Birch reductions that does not involve ammonia
https://phys.org/news/2021-11-birch-red ... monia.html
by Bob Yirka , Phys.org
A team of chemists at the University of Pittsburgh has developed a new way to conduct Birch reductions that does not require the use of ammonia, thus avoiding a dangerous procedure. In their paper published in the journal Science, the group describes the new method and the ways it can be used.

In chemistry, Birch reductions are organic reactions that convert arenes (aromatic hydrocarbons) to cyclohexadienes (six-carbon alicyclic hydrocarbons). They are typically used to build other complex molecules. The traditional method involves dissolving alkali metals in liquid ammonia—doing so produces the solvated electrons that drive the reaction. Importantly, such chemicals are hazardous, as is combining them. Chemists have been looking for a better alternative for many years. To date, most such efforts have resulted in processes deemed too hard to control, too expensive, or that require cryogenic conditions. The researchers note that some have suggested the Benkeser reduction can be used as a suitable replacement, but not for producing 1,4-cyclohexadienes. In this new effort, the team has found a new way to conduct Birch reductions without using ammonia. The process does not suffer from the drawbacks of the other modified procedures.
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Catalyst material exhibits baffling surface state
https://phys.org/news/2021-11-catalyst- ... state.html
by Vienna University of Technology

Sometimes chemical reactions in the lab work the way you imagine them to, and sometimes they don't. Neither is unusual. What is highly unusual, however, is what a research team at TU Wien has now observed when studying hydrogen oxidation on a rhodium catalyst: The surface of a rhodium foil can be highly chemically active in some surface regions, while in others, only a few micrometers away, it is completely inactive, and still in others oscillations between the active and inactive state occur. Such behavior was previously thought to be almost inconceivable. The results, which have now been published in the scientific journal Nature Communications, show that catalysis is more complicated than previously thought.

Basic principle of the fuel cell

"With the help of catalysts such as metallic rhodium, hydrogen can be oxidized—this is the basic reaction in fuel cells, with only water being produced as "waste gas," says Prof. Yuri Suchorski from the Institute of Materials Chemistry at TU Vienna. Hydrogen molecules are held on the rhodium surface and split into individual atoms, which then combine with oxygen to form water.
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Borophenes made easy
https://phys.org/news/2021-11-borophenes-easy.html
by Thamarasee Jeewandara , Phys.org
Synthetic organic chemists still aim to understand the scalable synthesis of elemental, two-dimensional (2D) materials beyond graphene. In a new report, Marc G. Cuxart and a team of researchers in physics, chemistry and electrical and computer engineering in France and Germany, introduced a versatile method of chemical vapor deposition (CVD) to grow borophenes and borophene heterostructures via the selective use of diborane originating from traceable byproducts of borazine. The team successfully synthesized metallic borophene polymorphs on Iridium (IR) (III) and Copper (Cu) (III) single-crystal substrates alongside insulating hexagonal boron nitride (hBN) to form atomically precise lateral borophene—hBN interfaces also known as vertical van der Waals heterostructures. This structure protected borophene from immediate oxidation due to the presence of a single insulating hBN overlayer. This direct approach and ability to synthesize high-quality borophenes with large single-crystalline domains via chemical vapor deposition can open a range of opportunities to study their fundamental properties. The work is now published in Science Advances.
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Experiment finds evidence for a long-sought particle comprising four neutrons

by Technical University Munich
https://phys.org/news/2021-12-evidence- ... trons.html
While all atomic nuclei except hydrogen are composed of protons and neutrons, physicists have been searching for a particle consisting of two, three or four neutrons for over half a century. Experiments by a team of physicists of the Technical University of Munich (TUM) at the accelerator laboratory on the Garching research campus now indicate that a particle comprising four bound neutrons may well exist.

While nuclear physicists agree that there are no systems in the universe made of only protons, they have been searching for particles comprising two, three or four neutrons for more than 50 years.

Should such a particle exist, parts of the theory of the strong interaction would need to be rethought. In addition, studying these particles in more detail could help us better understand the properties of neutron stars.

"The strong interaction is literally the force that holds the world together at its core. Atoms heavier than hydrogen would be unthinkable without it," says Dr. Thomas Faestermann, who directed the experiments.
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A bonding experience: Study reveals potential new family of compounds
https://phys.org/news/2021-12-bonding-r ... ounds.html
by Kathleen Haughney, Florida State University
On the Periodic Table of Elements, there are elements that most people remember from school—oxygen, hydrogen, gold and silver. But there are also the ones that you might not immediately recognize, such as berkelium and einsteinium. These exotic elements are typically only used in specialized laboratories to understand how chemistry and physics change at the extremes of the table.

Those heavy elements, particularly radioactive ones, are exceptionally difficult to modify and control for specific purposes. But a Florida State University research team has found that they could design a ligand —a functional group of molecules used to build complex compounds—out of molecules typically used in solar cell technologies and create a completely unexpected effect when bonding them with a radioactive element. When they paired that ligand with the element berkelium, it caused a significant shift in the electron density of the compound.
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Research team creates the world's lightest isotope of magnesium to date
https://phys.org/news/2021-12-team-worl ... esium.html
by Michigan State University
In collaboration with an international team of researchers, Michigan State University (MSU) has helped create the world's lightest version—or isotope—of magnesium to date.

Forged at the National Superconducting Cyclotron Laboratory at MSU, or NSCL, this isotope is so unstable that it falls apart before scientists can measure it directly. Yet this isotope that isn't keen on existing can help researchers better understand how the atoms that define our existence are made.

Led by researchers from Peking University in China, the team included scientists from Washington University in St. Louis, MSU, and other institutions.

"One of the big questions I'm interested in is where do the universe's elements come from," said Kyle Brown, an assistant professor of chemistry at the Facility for Rare Isotope Beams, or FRIB. Brown was one of the leaders of the new study, published online Dec. 22 by the journal Physical Review Letters.

"How are these elements made? How do these processes happen?" asked Brown.

The new isotope won't answer those questions by itself, but it can help refine the theories and models scientists develop to account for such mysteries.

Earth is full of natural magnesium, forged long ago in the stars, that has since become a key component of our diets and minerals in the planet's crust. But this magnesium is stable. Its atomic core, or nucleus, doesn't fall apart.
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Elusive atmospheric molecule produced in a lab for the 1st time
https://phys.org/news/2021-12-elusive-a ... b-1st.html
by University of Hawaii

The previously elusive methanediol molecule of importance to the organic, atmospheric science and astrochemistry communities has been synthetically produced for the first time by University of Hawaiʻi at Mānoa researchers. Their discovery and methods were published in Proceedings of the National Academy of Sciences on December 30.

Methanediol is also known as formaldehyde monohydrate or methylene glycol. With the chemical formula CH2(OH)2, it is the simplest geminal diol, a molecule which carries two hydroxyl groups (OH) at a single carbon atom. These organic molecules are suggested as key intermediates in the formation of aerosols and reactions in the ozone layer of the atmosphere.

The research team—consisting of Department of Chemistry Professor Ralf Kaiser, postdoctoral researchers Cheng Zhu, N. Fabian Kleimeier and Santosh Singh, and W.M. Keck Laboratory in Astrochemistry Assistant Director Andrew Turner—prepared methanediol via energetic processing of extremely low temperature ices and observed the molecule through a high-tech mass spectrometry tool exploiting tunable vacuum photoionization (the process in which an ion is formed from the interaction of a photon with an atom or molecule) in the W.M. Keck Laboratory in Astrochemistry. Electronic structure calculations by University of Mississippi Associate Professor Ryan Fortenberry confirmed the gas phase stability of this molecule and demonstrated a pathway via reaction of electronically excited oxygen atoms with methanol.
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