Tag: Chemistry

  • this gilded cousin of graphene is also one atom thick

    this gilded cousin of graphene is also one atom thick

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    It is the world’s thinnest gold leaf: a gossamer sheet of gold just one atom thick. Researchers have synthesized1 the long-sought material, known as goldene, which is expected to capture light in ways that could be useful in applications such as sensing and catalysis.

    Goldene is a gilded cousin of graphene, the iconic atom-thin material made of carbon that was discovered in 2004. Since then, scientists have identified hundreds more of these 2D materials. But it has been particularly difficult to produce 2D sheets of metals, because their atoms have always tended to cluster together to make nanoparticles instead.

    Researchers have previously reported single-atom-thick layers of tin2 and lead3 stuck to various substances, and they have produced gold sheets sandwiched between other materials. But “we submit that goldene is the first free-standing 2D metal, to the best of our knowledge”, says materials scientist Lars Hultman at Linköping University in Sweden, who is part of the team behind the new research. Crucially, the simple chemical method used to make goldene should be amenable to larger-scale production, the researchers reported in Nature Synthesis on 16 April1.

    “I’m very excited about it,” says Stephanie Reich, a solid-state physicist and materials scientist at the Free University of Berlin, who was not involved in the work. “People have been thinking for quite some time how to take traditional metals and make them into really well-ordered 2D monolayers.”

    In 2022, researchers at New York University Abu Dhabi (NYUAD) said that they had produced goldene, but the Linköping team contends that the prior material probably contained multiple atomic layers, on the basis of the electron microscopy images and other data that were published in ACS Applied Materials and Interfaces4. Reich agrees that the 2022 study failed to prove that the material was singler-layer goldene. The principal authors of the NYUAD study did not respond to Nature’s questions about their work.

    Golden age

    To prepare goldene, the Linköping researchers started with a material containing atomic monolayers of silicon sandwiched between titanium carbide. When they added gold on top of this sandwich, it diffused into the structure and exchanged places with the silicon to create a trapped atom-thick layer of gold (see ‘Gold mining’). They then etched away the titanium carbide to release free-standing goldene sheets that were up to 100 nanometres wide, and roughly 400 times as thin as the thinnest commercial gold leaf, Hultman estimates.

    GOLD MINING. Graphic shows the method researchers used to create goldene – a single layer of interconnected gold atoms.

    Source: Adapted from Ref. 1.

    That etching process used a solution of alkaline potassium ferricyanide known as Murukami’s reagent. “What’s so fascinating is that it’s a 100-year-old recipe used by Japanese smiths to decorate ironwork,” Hultman says. The researchers also added surfactant molecules — compounds that formed a protective barrier between goldene and the surrounding liquid — to stop the sheets from sticking together.

    The Linköping team suggests that goldene might be useful in applications in which gold nanoparticles already show promise. Light can generate waves in the sea of electrons at a gold nanoparticle’s surface, which can channel and concentrate that energy. This strong response to light has been harnessed in gold photocatalysts to split water to produce hydrogen, for instance. Goldene could open up opportunities in areas such as this, Hultman says, but its properties need to be investigated in more detail first.

    “I think the research is really interesting,” says Graham Hutchings, a chemist at the University of Cardiff, UK, who develops gold catalysts. But he worries that any residual traces of iron from Murukami’s reagent might hamper the development of goldene as a catalyst. “I would think that potential contamination with iron is going to cause a few problems in applications,” he says.

    For now, the Linköping researchers are seeking better ways to sieve goldene from the solution used to make it, and to grow larger flakes of the material. They are also exploring whether their method can be used to make monolayers of other catalytic metals, including iridium, platinum and palladium.

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  • We must protect the global plastics treaty from corporate interference

    We must protect the global plastics treaty from corporate interference

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    The global plastics treaty being negotiated this month in Ottawa epitomizes how people’s relationship with these valuable yet problematic materials is changing for the better. If it can be agreed on this year — as I hope it will — this treaty could end plastic pollution and lead to healthier societies. It could reduce the world’s reliance on fossil fuels and short-lived products. And it could lower people’s and nature’s exposures to hazardous chemicals and nano- and microplastics released by the 460 million tonnes of plastic produced globally each year (see go.nature.com/4auwzap).

    These negotiations also mark a shift in public attitudes towards plastics — from enabling modernity to being a hallmark of the Anthropocene. These materials contribute to the triple planetary crisis of climate change, biodiversity loss and pollution. And research — including my own — shows that plastics damage the health of both ecosystems and humans, by disrupting hormones, for example (see go.nature.com/4cqt8pj).

    The widespread support for the treaty is also striking. It comes from not only researchers, but also the public, civil society and businesses — “all the stars are aligned”, as one of my colleagues says. Swayed by scientists’ warnings and emboldened by public opinion, policymakers are willing to embark on this journey to end plastic pollution.

    In reality, however, not all stars are in alignment. Just as in global climate negotiations, countries and companies with vested interests are putting the treaty’s success at risk. The many nations striving for an ambitious treaty are being held hostage by those few that are locked politically and economically in a harmful plastics past. Reining in these vested interests is the key to unlocking a brighter plastics future.

    Resistance is coming from countries, such as Saudi Arabia and Russia, that depend on keeping fossil fuels flowing. They have obstructed constructive dialogue and are using delay tactics, such as lengthy discussions about procedural matters. One such debate revolves around whether the plastics treaty should be agreed on by consensus or through a majority vote. If consensus will be required, a single country could veto the treaty and prevent all the others from jointly addressing the problem.

    Corporations and representatives of fossil-fuel, chemical and plastics industries have similar vested interests. For instance, four times as many industry lobbyists as independent scientists had registered to attend last November’s round of negotiations in Nairobi. But such lobbyists operate more clandestinely than do researchers, through strategies decided in private boardrooms.

    On past form, it seems likely that some lobbyists will try to cast doubt on plastics research to slow down the negotiations. Artificially increasing the scientific uncertainty around tobacco’s adverse impacts on the climate has proved highly effective in delaying policy actions against such products, for example. Doubt, disguised as scientific critique, is cast by discrediting scientists and their research. Meanwhile, companies promote their own studies, which demonstrate a lack of harmful effects.

    In my opinion, the problem runs deeper still. I’m concerned that corporations are trying to control the scientific narrative by ‘domesticating’ the community. They create and support meetings, research projects and learned societies to ostensibly ‘support science’, while redefining it.

    For instance, in many industries, companies have long promoted the idea that polluting nature is acceptable until risk assessments show otherwise. Although this is an ethical rather than a scientific question, such reasoning allows potentially harmful products to remain on the market. In the treaty discussions, lobbyists will demand risk assessments to demonstrate plastics’ impacts on human health before taking action, work that would take decades to do.

    Bringing round fossil-fuel-dependent countries is a challenge for international diplomacy. But it is also crucial that nations take steps to limit corporate influences on the plastics treaty, particularly around the science. Here’s how.

    Strong competing-interest rules should be applied to all scientific matters. Participants in the treaty’s negotiation and implementation should be required to report any links to the fossil-fuel, chemical or plastics industries. Making such declarations public would enable scrutiny and accountability. The United Nations could support a mechanism to verify declarations, for instance.

    Policymakers should also insulate scientific bodies from corporate interference. Business views should pertain to developing solutions, not debating the science. And the two discussion streams should be kept separate. There is a precedent: the World Health Organization’s Framework Convention on Tobacco Control excludes from its work all experts with links to the tobacco industry. Such a rule does not prevent dialogues between science and stakeholders.

    I acknowledge that the private sector is not monolithic and comprises actors who want to contribute to a better plastics future, by supporting the Business Coalition for a Global Plastics Treaty, for instance. But the private sector must build trust by ceasing activities that intend to manufacture doubt. Resources would be better spent on innovating sustainable plastic materials and products.

    Thus, state and corporate interests must be reined in for the plastics treaty to be successful, benefiting nature, human health and businesses alike.

    Competing Interests

    M.W. is an unremunerated member of the Scientific Advisory Board of the Food Packaging Forum (FPF), a charitable foundation under Swiss law. The FPF does not advocate or lobby, but disseminates scientific information on food packaging to stakeholders and the public.

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  • Nanoparticle fix opens up tricky technique to forensic applications

    Nanoparticle fix opens up tricky technique to forensic applications

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    Nature, Published online: 17 April 2024; doi:10.1038/d41586-024-01015-6

    A technique called surface-enhanced Raman spectroscopy can detect tiny quantities of compounds in solution, but has been difficult to use for quantitative analysis. A digital approach involving nanoparticles suggests a way forward.

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  • Groundbreaking ruthenium catalyst developed for scientific discovery

    Groundbreaking ruthenium catalyst developed for scientific discovery

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    Researchers at The University of Manchester have developed a ruthenium catalyst with a wide range of uses.

    The new ruthenium catalyst is a groundbreaking advancement and has the potential to streamline the optimisation process in the industry.

    Scientists at The University of Manchester, in collaboration with AstraZeneca, developed the catalyst, which has proven to remain stable in the air for the long term while maintaining the high reactivity required to facilitate transformative chemical processes.

    The work has been published in Nature Chemistry.

    The importance of catalysts in the chemical industry

    Chemists often consider catalysts as the unsung heroes of chemistry. They are crucial in accelerating chemical reactions and play an instrumental role in the creation of manufactured products.

    For example, catalysts play an important role in the production of polyethylene – a common plastic used in various everyday items.

    Previous problems with ruthenium catalysts

    Ruthenium is a platinum group metal that has emerged as an important and commonly used catalyst.

    However, despite being a cost-effective material, highly reactive ruthenium catalysts have faced hindrances due to their sensitivity to air. This poses significant challenges in their application.

    Because of this, their use so far has been confined to highly trained experts with specialised equipment – limiting the full adoption of ruthenium catalysis across industries.

    Ruthenium’s new potential as a catalyst

    The new catalyst developed by the team overcomes this issue with its unparalleled reactivity and stability in the air.

    Lead author Gillian McArthur, PhD student at The University of Manchester, said: “As well as eliminating the need for specialised equipment or handling procedures, it also enables the user to run simultaneous reactions, facilitating rapid screening and streamlining optimisation procedures.

    “This means procedures are quicker, more environmentally friendly, and the accumulation of large amounts of waste is prevented.”

    The new catalyst will enable sustainable drug discovery

    The discovery allows for simple handling and implementation processes and has shown versatility across a wide array of chemical transformations. This makes it accessible for non-specialist users to exploit ruthenium catalysis.

    AstraZeneca has demonstrated the new catalyst’s applicability to the industry, showing its potential in developing efficient drug discovery and manufacturing processes.

    The new approach has resulted in discovering new reactions never before reported with ruthenium.

    Considering its enhanced versatility and accessibility, the team anticipate further advancements for the new catalyst.

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  • Life’s vital chemistry may have begun in hot, cracked rock

    Life’s vital chemistry may have begun in hot, cracked rock

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    3d rendered medically accurate illustration of amino acids

    Some amino acids can become concentrated as they travel through cracks in hot rock

    Sebastian Kaulitzki / Alamy

    Chemical reactions key to the origin of life on Earth could have occurred as molecules moved along thermal gradients within networks of thin rock fractures deep underground.

    Such networks, which would have been common on the early Earth, could have provided a kind of natural laboratory in which many of life’s building blocks were concentrated and separated from other organic molecules.

    “It’s very difficult to get a more general environment where you could have these purifications and intermediate steps,” says Christof Mast at the Ludwig Maximilian University of Munich in Germany.

    He and his colleagues created a heat flow chamber about the size of a playing card to model how a mix of organic molecules might behave in such rock fractures.

    They heated one side of the 170-micrometre-thick chamber to 25°C (77°F) and the other to 40°C (104°F), creating a temperature gradient along which molecules would move in a process called thermophoresis. How sensitive a molecule is to this process depends on its size and electrical charge and how it interacts with the fluid in which it is dissolved.

    In an 18-hour experiment in the heat flow chamber, they found a variety of molecules were concentrated at different parts of the chamber according to their sensitivity to thermophoresis. Among these molecules were many amino acids and the A, T, G and C nucleobases, which are a key component of DNA. This effect was magnified further when they created a network of three interconnected chambers, again with one side of the chamber network at 25°C and the other side at 40°C. The additional chambers further enriched compounds concentrated by the first.

    In a mathematical simulation with 20 interconnected chambers, which might better resemble the complexity of a natural system of fractures, they found the enrichment of different molecules could be amplified yet again. In one chamber, the amino acid glycine reached concentrations around 3000 times higher than that of a different amino acid, isoleucine, despite them entering the network at the same concentration.

    The researchers also demonstrated that this process of enrichment could enable a reaction to occur that would otherwise be extremely challenging. They showed that glycine molecules were able to bond to each other as the concentration of a molecule that catalyses the reaction called trimetaphosphate (TMP) increased. TMP is a noteworthy molecule to enrich as it would have been rare on the early Earth, says Mast. “Since [the chambers] are all randomly connected you could implement all sorts of reaction conditions.”

    “It’s extremely interesting to have regions in a crack with different ratios of compounds,” says Evan Spruijt at Radboud University in the Netherlands, who was not involved with the research. “You can create more diversity out of very simple building blocks with this added enrichment.”

    However, he says enrichment in rock fractures is still far from a viable scenario for an origin of life. “In the end, they still need to come together to form anything that resembles a cell or a protocell.”

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  • Trio of radicals choreographed for versatile chemical reaction

    Trio of radicals choreographed for versatile chemical reaction

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  • Flavour-predicting AI can tell brewers how to make beer taste better

    Flavour-predicting AI can tell brewers how to make beer taste better

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    Beer brewers generate a huge variety of flavours from just a handful of ingredients

    Kutredrig/Getty Images

    An artificial intelligence that can predict how a beer will taste from its chemical make-up could help create alcohol-free versions that taste just like regular ones.

    Predicting flavour from chemical compounds is difficult, as complex interactions between ingredients and the psychology of taste can make for surprisingly different perceptions, even between people sampling the same thing.

    To address this, Kevin Verstrepen at KU Leuven in Belgium and his colleagues have developed an AI model that can predict flavour profiles based on a beer’s chemical components and make suggestions for how to improve the flavour.

    The model was trained on beer reviews from a panel of 16 expert tasters, who scored each brew for 50 attributes, as well as 180,000 public ratings from an online beer reviewing website. It compared these subjective descriptions with measurements of 226 chemical compounds in 250 Belgian beers.

    “These hundreds of compounds are received by our nose and mouth, but mostly nose, and then processed in our brain to give what we think of as a flavour,” says Verstrepen. “The fact that now, with machine learning, you can actually accurately predict this is quite amazing.”

    Verstrepen and his team used the model to predict how to improve the flavour of a beer by adding a mixture of certain compounds, such as lactic acid and ethyl acetate. The resulting beer was given a significantly higher rating by the panel of trained tasters.

    In separate work that has yet to be published, non-alcoholic beers became indistinguishable from regular beer after making changes suggested by the model, says Verstrepen.

    The idea is that brewers should aim to implement the AI’s recommendations by tweaking their recipes, rather than simply adding flavours, he says. “In beer brewing, it’s not really acceptable to just add pure aroma compounds. It’s just malt, hops, water and yeast that have to do the trick.”

    “So, I really see it as a tool. It will be used especially to make better alcohol-free beer, but it’s not taking away the art of making good beer in an artisanal way,” says Verstrepen.

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    • chemistry /
    • food and drink

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  • From the archive: constantly quivering eyes, and chemistry troubles

    From the archive: constantly quivering eyes, and chemistry troubles

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    Nature, Published online: 19 March 2024; doi:10.1038/d41586-024-00683-8

    Snippets from Nature’s past.

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  • ‘Bandit’ algorithms help chemists to discover generally applicable conditions for reactions

    ‘Bandit’ algorithms help chemists to discover generally applicable conditions for reactions

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    • RESEARCH BRIEFINGS

    In organic chemistry, finding conditions that enable a broad range of compounds to undergo a particular type of reaction is highly desirable. However, conventional methods for doing so consume a lot of time and reagents. A machine-learning method has been developed that overcomes these problems.

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