Elusive carbon ring finally tamed for room-temperature research

Chemists at the University of Oxford have successfully synthesized a cyclocarbon molecule—specifically cyclo[48]carbon—as a [4]catenane that remains stable in solution at room temperature for up to 92 hours. This achievement marks a significant breakthrough in molecular science, as cyclocarbons were previously only observable fleetingly under extreme conditions such as in the gas phase or at cryogenic temperatures. The team’s innovative approach involved threading the C48 ring through three protective macrocycles, which shield the reactive carbon ring from degradation, and using a larger cyclocarbon to reduce molecular strain. The mild conditions employed during the final unmasking step further preserved the molecule’s integrity. The structure and stability of the cyclocarbon catenane were confirmed through various spectroscopic techniques, including mass spectrometry, NMR, UV-visible, and Raman spectroscopy. Notably, a single intense ^13C NMR resonance indicated a symmetrical environment for all 48 sp^1 carbon atoms,