Lanthanum endohedral metallofulleropyrrolidines: Synthesis, isolation, and EPR characterization

Lanthanum endohedral metallofulleropyrrolidines nave been synthesized for the first time through addition of an azomethine ylide to La@ C-82-A in toluene. It was found that the addition reaction is very efficient and, to some extent, regioselective. Two major endohedral metallofulleropyrrolidines, a monoadduct and a bisadduct of La@C-82-A with abundance ratio of similar to1:0.4, have been isolated by HPLC chromatography and characterized by mass spectrometry, UV/Vis-NIR absorption, and EPR spectroscopy. The electronic structure of La@C-82-A has been modified slightly upon monoaddition and significantly upon bisaddition of the pyrrolidines.