New metallofullerenes in the size gap of C-70 to C-82: From La-2@C-72 to Sc3N@C-80

The yield and stability of fullerenes with carbon cages in the size gap bet ween C-70 and C-84 is strongly dependent on the metals included. It is show n for C-72 and C-74 cages that they can be stabilised by metal ion inclusio n. A review is given for new fullerene structures. A number of new endohedr al fullerenes were isolated and described in their optical and redox proper ties. New fullerene structures presented are: La-2@C-72, Ce-2@C-72, Eu@C-74 , Tm@C-78, and Sc3N@C-80. The existence of a selected cage size and isomeri c cage is discussed with respect to the metal and its redox state.