Production and isolation of endohedral strontium- and barium-based mono-metallofullerenes: Sr/Ba@C82 and Sr/Ba@C84

We report the first isolation of strontium- and barium-based metallofullerenes and their characterisation by UV-vis-NIR absorption spectroscopy. The absorption spectra of the present samples (Sr/Ba@C82 and Sr/Ba@C84) show some similarity to their calcium-based analogues and are very different from those of yttrium- and lanthanum-based metallofullerenes. Assuming the barium atom to be in the 2+ state, which has an ionic radius of 1.34إ, the Ba-containing species represent the largest ionic radii-containing metallofullerenes so far isolated.