Phthalocyanines (Pcs) are planar, two-dimensional aromatic pophyrinoids which possess outstanding structural, optical and electrical properties as well as stability that render them perfect building blocks for the incorporation into multifunctional materials. Similarly, I_h-Sc₃N@C₈₀ fullerene – the most abundant member of the fullerenes family after C₆₀ and C₇₀ – in addition to have excellent electron-accepting properties, provides conditions for an extra stabilization of charge-separated states due to the presence of the internal Sc₃N species. This makes I_h-Sc₃N@C₈₀ an ideal molecular partner for photo- and electroactive molecular systems such as Pcs.

Although several reports have appeared on the preparation of covalent Sc₃N@I_h-C₈₀ ensembles, there is no use of I_h-Sc₃N@C₈₀ for the preparation of non-covalent assemblies. In this context, plenty of supramolecular systems arranged via coordination interactions have been successfully demonstrated for Pc-C₆₀ supramolecular dimers and trimers. Low accessability of non-covalent supramolecular systems with I_h-Sc₃N@C₈₀ is mainly caused by the more sophisticated synthesis and purification of the corresponding fullerene derivatives.

Herein, we report a novel example of donor-acceptor Pc/I_h-Sc₃N@C₈₀ supramolecular dimers assembled via metal-ligand coordination interactions between Zn(II)Pcs and pyridil-substituted I_h-Sc₃N@C₈₀  or C₆₀ fullerene. Photophysical (ground- and excited state) and electrochemical studies on these ensembles showed that depending on the electron-donor or electron-acceptor character of the ZnPcs, a switchable electron transfer reactivity occurs in the case of the I_h-Sc₃N@C₈₀ supramolecular systems, revealing the ability for this endohedral metallofullerene to behave either as electron donor or electron acceptor unit.