Counter-Rotating Ring Currents in Coronene and Corannulene.

Area of Science:

• Organic Chemistry
• Theoretical Chemistry
• Computational Chemistry

Background:

• The annulene-within-an-annulene model is a proposed electronic structure for [n]circulenes.
• Understanding aromaticity and electronic currents in polycyclic aromatic hydrocarbons is crucial.

Purpose of the Study:

• To investigate the electronic current distribution in [n]circulenes using ab initio methods.
• To test the validity of the annulene-within-an-annulene model for coronene and corannulene.

Main Methods:

• Calculation of explicit ab initio current-density maps.
• Analysis of electronic current flow in coronene and corannulene molecules.

Main Results:

• Current-density maps reveal a central paramagnetic ring current in both coronene and corannulene.
• This central paramagnetic current opposes the expected diamagnetic current on the perimeter.
• The findings contradict the predictions of the annulene-within-an-annulene model.

Conclusions:

• The annulene-within-an-annulene model is not an accurate representation of the electronic structure of coronene and corannulene.
• Ab initio current-density mapping provides a more accurate picture of aromaticity and electronic currents in these systems.