Selective formation of a symmetric Sc3N@C78 bisadduct:: Adduct docking controlled by an internal trimetallic nitride cluster

In this paper we reports regioselective Bingel-Hirsch reaction of Sc3N@C-78 yielding a single mono- and a dominate bis-ethyl malonate derivative for the first time. The C-s-symmetric monoadduct 1 and C-2v-symmetric bisadduct 2 were isolated by HPLC and characterized by MS, UV-vis, and NMR spectroscopy. The symmetric bisadduct 2 clearly demonstrate the remarkable regioselectivity control exerted by the encapsulated Sc3N cluster. We have employed a LUMO electron density surface computational approach to predict multiadduct docking sites on the ellipsoidal fullerene cage surface.