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 augmented pentalene structure could be a molecular Schrödinger's cat, aromatic and antiaromatic at the same time.
The discovery was made while studying quantum tunnelling, a phenomenon where particles can pass through a barrier they lack the energy to surmount, which appears in many automerisation reactions.
- Quantum tunnelling allows molecules to rearrange to an equivalent form of themselves.
- The mechanism enables molecules to tunnel from one well in the potential energy landscape to another.
Author's summary: Quantum tunnelling drives flip-flop in molecular structures.