A novel approach to the synthesis of endohedral fullerenes as demonstrated by endohedral barium fullerenes

A new route to endohedral fullerenes involving the evaporation of carbon and a metal at different positions, i.e. at different temperatures, in a radio-frequency furnace is described. For the first time, endohedral barium fullerenes within the composition range Ba@C-74 to Ba@C-136 have been produced in high yields as compared to hollow fullerenes, and have been extracted with CS2. Ba@C-60 and Ba@C-70 are only soluble in CS2 following sublimation. Furthermore, the first non-lanthanoid di-metallo fullerenes ranging in composition from Ba-2@C-88 to Ba-2@C-116 have been obtained. All endohedral barium fullerenes were characterized by mass spectrometry. Properties such as sublimation behaviour, solubility, and sensitivity to air have been studied.