Synthesis and Properties of a Buckybowl/Buckyball Dyad

In this work, we describe the synthesis of a molecule in which fullerene C₆₀ is covalently attached to a bowl-shaped polycyclic aromatic hydrocarbon, corannulene. The developed synthetic route is comprised of four linear steps with isolated yields ranging from 41-91%. The first three steps relate to the preparation of a hydrazone derivative of corannulene carrying a butyric acid methyl ester group. This key compound generates a reactive diazo moiety under base-induced decomposition process. The generated diazoalkane then adds to the C₆₀ molecule to furnish the targeted corannulene-C₆₁-butyric acid methyl ester (CCBM) molecule. This compound is structurally characterized by NMR spectroscopy and mass spectrometry, whereas material properties are determined with the help of optical absorption spectroscopy and cyclic voltammetry. Finally, some preliminary aspects on its application are examined in a poly(3-hexyl thiophene)-based photovoltaic device.