Quantum Tunnelling Drives Aromaticity Flip-Flop
Researchers in Israel have discovered molecules that can switch between aromatic and antiaromatic structures rapidly, or even adopt both at once.
Aromatic and antiaromatic structures are two distinct personas in cyclic chemistry, with aromatics like benzene being stable and serene, and antiaromatics like pentalene being fractious and flighty.
The researchers at Ben-Gurion University of the Negev and Technion-Israel Institute of Technology made the find while studying quantum tunnelling.
Quantum tunnelling is a phenomenon where particles can pass through a barrier they lack the energy to surmount, appearing in many automerisation reactions.
The researchers found that this mechanism can drive the flip-flop between aromatic and antiaromatic structures, creating a molecular "Schrödinger's cat" that can be both at the same time.
The discovery was made while studying the augmented pentalene structure, which could exhibit this unique property.
Author's summary: Quantum tunnelling enables aromaticity flip-flop in molecules.