The key role of aromaticity in the structure and reactivity of C60 and endohedral metallofullerenes

Abstract

In this review, we show that the local aromaticity of C60 and endohedral metallofullerenes (EMFs) is a key factor to understand and predict their structure and reactivity. We report recent examples provided by our group that highlight the importance of aromaticity in C60 and EMFs. First example discusses the regioselectivity of Diels-Alder reactions in reduced C60; the second one analyzes how aromaticity stabilizes the most suitable hosting cages in EMFs; the third one determines the effect of aromaticity in the relative abundances of EMFs; the fourth one shows a relationship between aromaticity and the stability of EMF adducts formed in Bingel-Hirsch (BH) reactions; and the last one proposes structural criteria to predict the regioselectivity in BH reactions based on the local aromaticity of EMFs.

Theoretical Insights into Monometallofullerene Th@C76: Strong Covalent Interaction between Thorium and the Carbon Cage

“…Entrapping metal atoms or metal-containing clusters in fullerene cages results in the formation of endohedral metallofullerenes (EMFs). , The encapsulated species significantly influence the electronic and magnetic properties of these hybrid molecules. , Recently, maximum pentagon separation and aromaticity rules were proposed to interpret the preferred encapsulation cage for EMF formation. − The former pointed out that the negative charge in the EMFs mainly accumulated in the pentagons and preferred the cages with the largest separation among the 12 pentagons. The latter indicates that maximizing the total aromaticity is the main stabilizing force for highly charged fullerenes or EMFs.…”