Resonance and Strain Energies in Non-planar Cyclic Conjugate Molecules

How they control the thermodynamic stability

Abstract

This paper deals with resonance and strain energies in non-planar cyclic conjugate molecules, such as C₆₀ and corannulene 1, including quantitative discussions based on combustion calorimetry. Before the evaluation of those energies, energetics of planar aromatic molecules is reasoned in order to provide reference energies. The energetics is extended to the non-planar sp² carbon networks. The formation enthalpies of graphite fragments, hollow fullerenes and fullerene onions are predicted as functions of the number of carbon atoms. Fullerenes are predicted to be less stable than infinite size of graphite, but to be more stable than finite size of graphite fragments. Among aggregates of around 1000 carbon atoms, fullerene onions are found to be more stable than hollow fullerened and graphite fragments.