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Amino acid esters react with C60 both thermally and photochemically to give different products. Refluxing a mixture of C60 and glycine ethyl ester afforded C60(Me2CHNHCHCOOEt) 1, whereas irradiation of the same mixture produced C60(EtOOCCHNHCHCOOEt) 2b as the main product. Photochemical reactions between C60 and sarcosine esters yielded two pyrrolidine derivatives C60(CH2N(Me)CHCOOR) 3 and C60(ROOCCHNHCHCOOR) 2 (R = Me, Et, CH2Ph). Compound 2a is also prepared from the photochemical reaction between C60 and iminodiacetic methyl ester in high yield. These ester derivatives are difficult to hydrolyze in excess mineral acids. The fullerene dicarboxylic acid C60(HOOCCHNHCHCOOH) 5 is synthesized from the tert-butyl derivative C60(tBuOOCCHNHCHCOOtBu) 4. A possible radical reaction mechanism for the photochemical reactions is proposed which involves an unprecedented C−N bond breakage.

Aminopolycarboxylic esters react with C60 under photolysis to produce fullerene multicarboxylates. Irradiation of tetramethyl ethylenediaminetetraacetate (EDTA) with C60 yields the EDTA-containing fullerene monoadduct C60(MeOOCCH)2NCH2CH2N(CH2COOMe)2. In addition, several other C60 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 C60, decarboxylation occurs and organodihydrofullerene derivatives such as C60(H)(CH2N(CH2COOMe)2) are formed. Radical mechanisms are proposed for both types of photoreactions. The fullerene derivatives are characterized by their spectroscopic data. Photoreactions of C60 with other analogous molecules also support the conclusions.

[reaction: see text] tert-Butylperoxy radicals add to [70]fullerene to form a mixture of adducts C(70)(OO(t)()Bu)(n)() (n = 2, 4, 6, 8, 10). Four isomers were isolated for the bis-adduct with the two tert-butylperoxo groups attached at 1,2-, 5,6-, 7,23-, and 2,5-positions, respectively. Two isomers were isolated for the tetrakis-adduct with the tert-butylperoxo groups located along the equator in C(s)() symmetry and on the side in C(1) symmetry, respectively. Similarly, two isomers were isolated for the hexakis-adducts with a structure related to the tetrakis-adducts, one of which has the cyclopentadienyl substructure. No isomer was detected for the octakis- and decakis-adducts. The C(s)()-symmetric octakis- and C(2)-symmetric decakis-adducts have all the tert-butylperoxo groups located along the equator. The decakis-adduct is the major product under optimized conditions. The compounds were characterized by their spectroscopic data. Chemical correlation through further addition of tert-butylperoxy radicals to isolated pure derivatives confirmed the structure assignment. Mechanisms of the tert-butylperoxy radical addition to C(70) follow two pathways: equatorial addition along the belt and cyclopentadienyl addition on the side.