Chemicals can change their identity, thanks to the liquids where they reside

February 11, 2019, US Department of Energy
A “snapshot” reveals that the surrounding tetrahydrofuran solvent deforms the bonding electron density around a sodium solute. The sodium cores are blue spheres; the valence electrons' density is represented as a transparent white surface with a white wire mesh enclosing most of the charge density. The bonds between sodium and nearby solvent’s oxygen sites are thin yellow lines. Credit: Devon Widmer, University of California, Los Angeles

Toss a few whole almonds in a jar full of hazelnuts. Shake. The nuts bounce against each other, but they don't react. That's how some people think of reactions happening inside liquids. The solutes (almonds) react with each other in a sea of solvent (hazelnuts). But a new study shows that this is not always the case for real chemical reactions. Under the right conditions, the solvent can change the chemical identity of the solute.

Many , particularly those relevant to keeping people and plants alive, happen in solution. This research shows that in many such reactions, the solvent is not a mere spectator. That means retooling expectations and computational models. Because the same rules could apply in chemistry labs, researchers may need to select their solvents with more care. The solvents could be controlling or changing the identity of the solute.

Although solvents are carefully selected in some cases, the liquids are often simply considered a medium to allow the reactants to encounter each other. However, the solvent may play a larger role. Here, researchers found that when the solvent and solute interact (energetically on the same order as a hydrogen bond), the solvent can control the bond dynamics and the chemical identity of simple solutes. The researchers came to this conclusion studying a sodium dimer in the weakly polar solvent tetrahydrofuran. Bonding interactions between the solvent and sodium atoms led to unique coordination states. These states had to cross a free energy barrier, essentially undergoing a chemical reaction, to interconvert. Further, each coordination state had its own dynamics and spectroscopic signatures. Although chemists have long been aware of the influence of solvents in certain cases, this research highlights the value of carefully selecting the to create a specific environment in certain condensed-phase chemical systems.

Explore further: Boosting solid state chemical reactions

More information: Devon. R. Widmer et al. Solvents can control solute molecular identity, Nature Chemistry (2018). DOI: 10.1038/s41557-018-0066-z

Related Stories

Boosting solid state chemical reactions

February 8, 2019

A cross-coupling reaction is typically performed in an organic solvent and leads to the production of a large amount of solvent waste, which is often harmful to the environment. A new strategy developed by Hokkaido University ...

How solvent molecules cooperate in reactions

October 6, 2016

Molecules from the solvent environment that at first glance seem to be uninvolved can be essential for chemical reactions. This has been shown by researchers studying the formation of an ether in pure solvents and in their ...

Better biomass conversion for biofuels and bioproducts

March 14, 2018

Behind the successful conversion of biomass to a better biofuel or a new green chemical, there is a carefully chosen solvent. The right solvent not only dissolves biomass but also drives the efficiency of the entire conversion ...

Chemistry in a trillionth of a second

January 30, 2015

Chemists at the University of Bristol, in collaboration with colleagues at the Central Laser Facility at the Rutherford Appleton Laboratory (RAL) and Heriot-Watt University (HWU), can now follow chemical reactions in liquids ...

Nanoparticle colloid systems in molten inorganic salts

March 6, 2017

(—Colloidal systems are important in nanoscience and materials. A colloidal system involves the dispersion of particles within a solvent. A stable colloid has evenly dispersed solute particles while unstable colloids ...

Recommended for you

Where is the universe hiding its missing mass?

February 15, 2019

Astronomers have spent decades looking for something that sounds like it would be hard to miss: about a third of the "normal" matter in the Universe. New results from NASA's Chandra X-ray Observatory may have helped them ...

What rising seas mean for local economies

February 15, 2019

Impacts from climate change are not always easy to see. But for many local businesses in coastal communities across the United States, the evidence is right outside their doors—or in their parking lots.


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.