Synthesis of Pyrrolidine Ring-Fused Fullerene Multicarboxylates by Photoreaction

Aminopolycarboxylic esters react with C 60 under photolysis to produce fullerene multicarboxylates. Irradiation of tetramethyl ethylenediaminetetraacetate (EDTA) with C 60 yields the EDTA-containing fullerene monoadduct C 60 (MeOOC C H) 2 NCH 2 CH 2 N(CH 2 COOMe) 2 . In addition, several other C 60 monoadducts are also isolated and characterized, including compounds due to EDTA fragmentation. Similar results are observed with pentamethyldimethylenetriaminepentaacetate (DTPA). When partially methylated nitrilotriacetic acid is irradiated with C 60, decarboxylation occurs and organodihydrofullerene derivatives such as C 60 (H)(CH 2 N(CH 2 COOMe) 2 ) are formed. Radical mechanisms are proposed for both types of photoreactions. The fullerene derivatives are characterized by their spectroscopic data. Photoreactions of C 60 with other analogous molecules also support the conclusions.