This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: In a study published in Nature Chemistry, an international team of researchers from Germany and the U.K., including chemists from The University of Manchester, has synthesized and characterized what they describe as the first isolable uranium Fischer-type carbyne, a compound in which carbon forms an unusual triple-bond interaction with uranium. The findings give researchers a clearer example of how uranium can form multiple bonds with carbon, providing a new reference point for comparing the chemistry of actinides with more familiar transition metals.
The discovery also demonstrates a new way of building previously inaccessible uranium compounds, expanding the toolkit for studying heavy-element chemistry. Metal-carbon triple bonds are well established in transition-metal chemistry, but creating an equivalent uranium compound stable enough to isolate and study has proved much more challenging. Until now, related uranium examples had only been observed under highly specialized conditions, such as at extremely low temperatures or when trapped inside hollow carbon molecules known as fullerene cages.
The team, including professor Stephen Liddle, John Seed, Ashley Wooles, Floriana Tuna and Adam Brookfield, used a new synthetic strategy combining a uranium precursor with a recently developed carbon-atom transfer reagent, enabling them to create the compound and study it in detail. To confirm the discovery, the researchers used single-crystal X-ray diffraction, spectroscopy, magnetometry and advanced computational analysis. Together, these methods showed that the new compound has the key features expected for a Fischer-type carbyne.
"This work addresses a longstanding challenge in f-element chemistry. By isolating and studying this compound in detail, we have been able to show that uranium can support a Fischer-type carbyne interaction that is related to, but distinct from, those previously established for transition metals. "The result expands our understanding of how uranium engages in multiple bonding with carbon and provides a foundation for exploring new areas of actinide chemistry," said Liddle, professor of inorganic chemistry and co-director of the Centre for Radiochemistry Research.
The team's measurements showed that the uranium and carbon atoms sit 2.379(15) Å apart. In chemical structures, multiple bonding usually requires shorter distances, but in this case quantum crystallography was used to visualize and confirm the uranium–carbon triple-bond interaction. Further analysis showed that this bond is formed through two-way electron sharing: carbon donates two electrons to uranium, while uranium also donates electrons back to carbon, in this case through two orthogonal one-electron bonds, a rare arrangement.
The compound was also found to be relatively unreactive, which is what chemists would expect for this type of Fischer carbyne. Additional experiments showed that the bonding could be changed through chemical reduction, giving the team further evidence for how the compound's electrons are arranged. The findings are primarily important for fundamental chemistry.
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