As simple as bonding gets?
In all the Nobel prize excitement last week, you might have missed the news that researchers in Japan have isolated a compound featuring a one-electron σ-bond between two carbon atoms.
This is by no means the first instance of a one-electron bond. They mainly exist in radical ions, making them difficult to isolate and characterize. In January, a team in China reported a compound with a one-electron tin–tin bond, which they described as the first example of a heavier main-group metal–metal complex featuring a two Centre–one electron bond. You can also find examples of phosphorus–phosphorus, copper–boron, copper–aluminum, copper–gallium and beryllium–beryllium one-electron bonds in the literature. Carbon’s ubiquity and versatility, however, makes creating a one-electron bond with it just that little bit more exciting.
In 2022, David de Sousa and Marco Nascimento, from the Federal University of Rio de Janeiro in Brazil, asked whether one-electron bonds are any different from standard two-electron covalent bonds. Energy analysis led them to conclude that both bonds result from quantum interference among the atomic orbitals, so the nature of both bonds is the same. They’re also clear that one-electron bonds should not be described as half-bonds.
And while it will be worth seeing if this carbon–carbon one-electron bond brings anything new to debates surrounding the nature of chemical bonds, I’m far more interested in the design strategy the team employed to create the bond and what other structures might follow.
The scale of the problem of replacing PFAS
The extreme persistence of per- and polyfluoroalkyl substances (PFAS) and their associated risks mean many countries are looking to phase out these chemicals. In this article, Rebecca Trager explores how different classes of consumer goods might adapt to these impending regulations, as well as growing public awareness. When it comes to frying pans, for example, PFAS-free versions made from cast iron, ceramic or stainless steel already exist – although they’re typically more expensive and harder to clean. Avoiding PFAS in healthcare, however, is going to be more difficult; catheters, stents and surgical meshes all contain PFAS to make them hydrophobic to prevent infections and clots. Without PFAS, such devices may need replacing more often, meaning higher costs and more discomfort for patients.
Emerging solid-state cycloaddition chemistry for molecular solar thermal energy storage
Last week we reported on research that showed how incorporating a layer of photoswitching molecules into a solar cell helped the device perform more efficiently in the heat. The photoswitching layer represents a molecular solar thermal energy storage system, which stores sunlight within chemical bonds by switching into a different metastable isomer, and here it comprises a solution of organic molecules. This Chemical Science perspective, however, explores how recent discoveries surrounding [2+2] and [4+4] photocycloaddition reactions involving structures including styryldipyryliums and anthracenes, respectively, means research into solid-state molecular solar thermal energy storage systems is gathering steam. Solid-state materials are of interest because they’re easier to incorporate into garments, windows and other products for various self-charging and heating applications. They also tend to have higher overall energy densities than those of solution-state systems. To move the field forward, researchers must better understand the effect of variables such as intermolecular interactions in close-packed crystals.
The food of space travel could be based on rocks
Space explorers of the future could be eating rocks, or at least the bacterial products of their breakdown. The need to either carry massive amounts of food or periodically rendezvous with Earth for supplies, limits how long any space mission can be. Now, inspired by research done by the US Department of Defense into repurposing plastic food packaging, scientists from Western University in Canada have investigated using asteroids as a food source.
Carbonaceous chondrite asteroids are the most abundant type in our solar system, and, like plastic packaging, are carbon rich. By chemically and physically breaking the asteroids down, and feeding the resulting hydrocarbons to colonies of bacteria, they can be transformed into biomass that could sustain interstellar travellers on long voyages. The idea is purely hypothetical for the moment, but previous research has shown that bacteria can grow when fed only meteorite material. According to the team’s calculations, an asteroid like Bennu, which has a mass of 85.5 million tons, could provide enough calories to sustain one human for 600 to 17,000 years, depending on the efficiency of biomass extraction and conversion. It wouldn’t exactly be astronaut ice cream, but bacterial biomass could be one of the keys to unlocking interstellar exploration.
How taking part in extracurricular activities during your PhD can help you build your CV
During a PhD, it’s not only in the lab or in the office where learning can take place. Extracurricular activities also allow researchers to gain skills and experiences that will be useful for their future careers, as Victoria Atkinson explores in the latest Chemistry World careers article. Whether it’s building leadership skills through teaching, developing communication skills through outreach or learning how to organise departmental events, there’s a rich source of opportunities for PhD researchers to take advantage of. While most of these activities are advertised within universities, members of the Royal Society of Chemistry can also find other opportunities through the volunteering opportunities board.
As men dominate Nobels again, one selector sees slow progress toward greater diversity
Women were relatively well represented among the 2023 science Nobel prizes but 2024 reverted to a clean sweep of all-male laureates. In 2018, the organisations that award these prizes began adjusting their nomination and selection processes in an attempt to address gender and ethnicity imbalances. This included inviting nominations from more female professors, as well as professors in all parts of the world. Nomination instructions also now emphasise that just a name is enough – there is no expectation for nominators to pull together a justification because each committee performs its own investigation. However, Pernilla Wittung-Stafshede, a biophysical chemist on the chemistry Nobel committee, describes the response rate from nominators outside of Europe and the US as ‘generally poor’. She suggests that maybe the committee should be looking into topics without nominations. Nevertheless, Wittung-Stafshede reports several new nominations for names that haven’t come up before: ‘I see that as really positive, because those new areas that we go into are more diverse in terms of the scientists that come on the table.’
Even a single bacterial cell can sense the seasons changing
‘Very nonsensical’ – that’s how Luísa Jabbur, a researcher now at the John Innes Center in Norwich, UK, described finding that a species of cyanobacteria anticipates the arrival of winter by adjusting its membrane lipids and gene expression to accommodate cold conditions. Photoperiodism, or daylength sensing, is easily observed in deciduous trees, for example, which ditch their leaves in autumn. Given cyanobacteria divide after five or six hours, it has come as a surprise to many that such a short-lived organism would develop a mechanism to track the seasons – it must therefore mean that this trait has evolved to benefit the population rather than the individual.