Fullerene based endohedral metallocenes

► Metal ion interacts less with curved five membered ring than that of planar. ► Formation of (η5-Cp)Fe+@C60 complex is energetically not feasible (steric effect). ► The incarceration of (η5-Cp)Fe+ inside C80 and C180 is energetically possible. ► Endohedral sandwich complexes can act as good oxidizing agents.